FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Holmes, TRH Owe, M De Jeu, RAM Kooi, H AF Holmes, T. R. H. Owe, M. De Jeu, R. A. M. Kooi, H. TI Estimating the soil temperature profile from a single depth observation: A simple empirical heatflow solution SO WATER RESOURCES RESEARCH LA English DT Article AB Two field data sets are used to model near-surface soil temperature profiles in a bare soil. It is shown that the commonly used solutions to the heat flow equations by Van Wijk perform well when applied at deeper soil layers, but result in large errors when applied to near surface layers, where more extreme variations in temperature occur. The reason for this is that these approaches do not consider heat sources or sinks below the surface. This paper proposes a new approach for modeling the surface soil temperature profiles from a single observation depth. This approach consists of two parts: 1) modeling an instantaneous ground flux profile based on net radiation and the ground heat flux at 5 cm depth; and 2) use of this ground heat flux profile to extrapolate a single temperature observation to a complete surface temperature profile. The new model is validated under different field and weather conditions showing low RMS errors of 1-3 K for wet to dry conditions. Finally, the proposed model is tested under limitations in input data that are associated with remote sensing applications. It is shown that these limitations result in only small increases in the overall error. This approach may be useful for satellite-based global energy balance applications. C1 [Holmes, T. R. H.; De Jeu, R. A. M.; Kooi, H.] Vrije Univ Amsterdam, Dept Geoenvironm Sci, Amsterdam, Netherlands. [Owe, M.] NASA GSFC, Hydrol Sci Branch, Greenbelt, MD USA. RP Holmes, TRH (reprint author), Vrije Univ Amsterdam, Dept Geoenvironm Sci, Amsterdam, Netherlands. RI Holmes, Thomas/F-4512-2010 OI Holmes, Thomas/0000-0002-4651-0079 NR 15 TC 23 Z9 23 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD FEB 6 PY 2008 VL 44 IS 2 AR W02412 DI 10.1029/2007WR005994 PG 11 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 261HR UT WOS:000253070200004 ER PT J AU El Amraoui, L Semane, N Peuch, VH Santee, ML AF El Amraoui, L. Semane, N. Peuch, V. -H. Santee, M. L. TI Investigation of dynamical processes in the polar stratospheric vortex during the unusually cold winter 2004/2005 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE LOSS; ARCTIC OZONE; ASSIMILATION; TRANSPORT; SATELLITE AB The 2004/2005 Arctic winter was unusually cold with high potential for Polar Stratospheric Clouds formation. We use O(3) and N(2)O assimilated fields from Aura/MLS in order to describe the dynamical processes inside the polar vortex during this winter. The evolution of N(2)O assimilated field shows that subsidence was the dominant dynamical process between early December and late January. The mixing effect between the polar vortex and midlatitudes has been diagnosed using the effective diffusivity parameter. It shows that from early February to the end of March, mixing was dominant compared to diabatic descent. The vortex-averaged ozone loss profile from O(3) assimilated field shows a maximum of similar to 1.5 ppmv at 425 K, which is less pronounced compared to other winters of similar meteorological conditions (e. g., 1999/2000). This is due to the importance of the mixing processes between the polar vortex and midlatitudes which bring in ozone-rich air to the vortex. C1 [El Amraoui, L.; Semane, N.; Peuch, V. -H.] Meteo France, CNRM GMGEC CARMA, CNRM GAME, CNRS,URA 1357, F-31057 Toulouse, France. [El Amraoui, L.] Univ Toulouse 3, CNRS, UMR 5560, Lab Aerol, F-31062 Toulouse, France. [Semane, N.] CNRM DMN, Casablanca, Morocco. [Santee, M. L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP El Amraoui, L (reprint author), Meteo France, CNRM GMGEC CARMA, CNRM GAME, CNRS,URA 1357, 42 Ave G Coriolis, F-31057 Toulouse, France. EM elamraoui@cnrm.meteo.fr RI Peuch, Vincent-Henri/A-7308-2008 NR 23 TC 25 Z9 25 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 5 PY 2008 VL 35 IS 3 AR L03803 DI 10.1029/2007GL031251 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 261FB UT WOS:000253063400001 ER PT J AU Kwok, R AF Kwok, Ron TI Summer sea ice motion from the 18 GHz channel of AMSR-E and the exchange of sea ice between the Pacific and Atlantic sectors SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID IMAGERY AB We demonstrate that sea ice motion in summer can be derived reliably from the 18GHz channel of the AMSR-E instrument on the EOS Aqua platform. The improved spatial resolution of this channel with its lower sensitivity to atmospheric moisture seems to have alleviated various issues that have plagued summer motion retrievals from shorter wavelength observations. Two spatial filters improve retrieval quality: one reduces some of the microwave signatures associated with synoptic-scale weather systems and the other removes outliers. Compared with daily buoy drifts, uncertainties in motion are similar to 3-4 km/day. Using the daily motion fields, we examine five years of summer ice area exchange between the Pacific and Atlantic sectors of the Arctic Ocean. With the sea-level pressure patterns during the summer of 2006 and 2007 favoring the export of sea ice into the Atlantic Sector, the regional outflow is similar to 21% and similar to 15% of the total sea ice retreat in the Pacific sector. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ron.kwok@jpl.nasa.gov RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 6 TC 47 Z9 49 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 5 PY 2008 VL 35 IS 3 AR L03504 DI 10.1029/2007GL032692 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 261FB UT WOS:000253063400007 ER PT J AU Yuan, W Hu, LB Yu, ZB Lam, TL Biggs, J Ha, SM Xi, DJ Chen, B Senesky, MK Gruner, G Pei, QB AF Yuan, Wei Hu, Liangbing Yu, Zhibin Lam, Tuling Biggs, James Ha, Soon M. Xi, Dongjuan Chen, Bin Senesky, Matthew K. Gruner, George Pei, Qibing TI Fault-tolerant dielectric elastomer actuators using single-walled carbon nanotube electrodes SO ADVANCED MATERIALS LA English DT Article ID NETWORKS; EMISSION AB Fault-tolerant actuators. Single-waited carbon nanotubes were studied as new compliant electrodes for dielectric elastomers. The spray-coated SWNT electrodes drive electromechanical strains greater than 200 %. When a fault is present due to pin puncture or internal defect in the elastomer films, dielectric breakdown causes localized self-clearing of the SWNT electrodes and isolation of the fault. The increased fault tolerance may enhance the actuation reliability of dielectric elastomers actuators. C1 [Yuan, Wei; Yu, Zhibin; Lam, Tuling; Ha, Soon M.; Xi, Dongjuan; Pei, Qibing] Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA. [Hu, Liangbing; Gruner, George] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. [Biggs, James; Senesky, Matthew K.] Artificial Muscle Inc, Menlo Pk, CA 94303 USA. [Chen, Bin] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pei, QB (reprint author), Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA. EM qpei@seas.ucla.edu RI Hu, Liangbing/C-5589-2011; Yu, Zhibin/F-6650-2011; Hu, Liangbing/N-6660-2013; Pei, Qibing/N-7497-2015 NR 26 TC 97 Z9 98 U1 5 U2 66 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD FEB 4 PY 2008 VL 20 IS 3 BP 621 EP + DI 10.1002/adma.200701018 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 264YE UT WOS:000253325500045 ER PT J AU Mohageg, M Maleki, L AF Mohageg, Makan Maleki, Lute TI Reconfigurable optical spectra from perturbations on elliptical whispering gallery resonances SO OPTICS EXPRESS LA English DT Article ID MODES AB Elastic strain, electrical bias, and localized geometric deformations were applied to elliptical whispering-gallery-mode resonators fabricated with lithium niobate. The resultant perturbation of the mode spectrum is highly dependant on the modal indices, resulting in a discretely reconfigurable optical spectrum. Breaking of the spatial degeneracy of the whispering-gallery modes due to perturbation is also observed. (C) 2008 Optical Society of America. C1 [Mohageg, Makan; Maleki, Lute] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mohageg, M (reprint author), CALTECH, Dept Appl Phys, Pasadena, CA 91125 USA. EM makan@caltech.edu NR 23 TC 1 Z9 1 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD FEB 4 PY 2008 VL 16 IS 3 BP 2037 EP 2047 DI 10.1364/OE.16.002037 PG 11 WC Optics SC Optics GA 259IH UT WOS:000252932500071 PM 18542283 ER PT J AU Mishchenko, MI AF Mishchenko, Michael I. TI Multiple scattering by particles embedded in an absorbing medium. 1. Foldy-Lax equations, order-of-scattering expansion, and coherent field SO OPTICS EXPRESS LA English DT Article ID EXTINCTION COEFFICIENT; LIGHT-SCATTERING AB This paper presents a systematic analysis of the problem of multiple scattering by a finite group of arbitrarily sized, shaped, and oriented particles embedded in an absorbing, homogeneous, isotropic, and unbounded medium. The volume integral equation is used to derive generalized Foldy-Lax equations and their order-of-scattering form. The far-field version of the Foldy-Lax equations is used to derive the transport equation for the so-called coherent field generated by a large group of sparsely, randomly, and uniformly distributed particles. The differences between the generalized equations and their counterparts describing multiple scattering by particles embedded in a non-absorbing medium are highlighted and discussed. (c) 2008 Optical Society of America. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mmishchenko@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 13 TC 17 Z9 17 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD FEB 4 PY 2008 VL 16 IS 3 BP 2288 EP 2301 DI 10.1364/OE.16.002288 PG 14 WC Optics SC Optics GA 259IH UT WOS:000252932500096 PM 18542308 ER PT J AU Branduardi-Raymont, G Elsner, RF Galand, M Grodent, D Cravens, TE Ford, P Gladstone, GR Waite, JH AF Branduardi-Raymont, G. Elsner, R. F. Galand, M. Grodent, D. Cravens, T. E. Ford, P. Gladstone, G. R. Waite, J. H., Jr. TI Spectral morphology of the X-ray emission from Jupiter's aurorae SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EXTREME ULTRAVIOLET OBSERVATIONS; XMM-NEWTON; ENCOUNTER; OVAL AB Simultaneous Chandra X-ray and Hubble Space Telescope FUV observations of Jupiter's aurorae carried out in February 2003 have been re-examined to investigate the spatial morphology of the X-ray events in different energy bands. The data clearly show that in the Northern auroral region (in the main auroral oval and the polar cap) events with energy > 2 keV are located at the periphery of those with energy < 2 keV and coincide with FUV bright features. In addition, X-ray spectra extracted from the areas where the two event distributions are concentrated possess different shapes. We associate the > 2 keV events (similar to 45 MW emitted power) with the electron bremsstrahlung component recently revealed by XMM-Newton in the spectra of Jupiter's aurorae, and the < 2 keV emission (similar to 230 MW) with the product of ion charge exchange, now established as the likely mechanism responsible for the soft X-ray Jovian aurora. We suggest that the same population of energetic electrons may be responsible for both, the X-ray bremsstrahlung and the FUV emission of Jupiter's aurorae. Comparison of the > 2 keV X-ray and FUV (340 GW) powers measured during the observations shows that they are broadly consistent with the predicted emissions from a population of energetic electrons precipitating in the planet's atmosphere, thus supporting our interpretation. C1 [Branduardi-Raymont, G.] UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. [Cravens, T. E.] Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. [Elsner, R. F.] NASA, George C Marshall Space Flight Ctr, NSSTC XD12, Space Sci Branch, Huntsville, AL 35805 USA. [Ford, P.] Harvard Univ, MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. [Galand, M.] Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Space & Atmospher Phys Grp, London SW7 2BW, England. [Gladstone, G. R.; Waite, J. H., Jr.] SW Res Inst, San Antonio, TX 78228 USA. [Grodent, D.] Univ Liege, Lab Phys Atmospher & Planetaire, Inst Astronphys & Geophys, B-4000 Liege, Belgium. RP Branduardi-Raymont, G (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM gbr@mssl.ucl.ac.uk RI Galand, Marina/C-6804-2009 NR 22 TC 31 Z9 31 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 2 PY 2008 VL 113 IS A2 AR A02202 DI 10.1029/2007JA012600 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258RL UT WOS:000252887100003 ER PT J AU Sudbrack, CK Ziebell, TD Noebe, RD Seidman, DN AF Sudbrack, Chantal K. Ziebell, Tiffany D. Noebe, Ronald D. Seidman, David N. TI Effects of a tungsten addition on the morphological evolution, spatial correlations and temporal evolution of a model Ni-Al-Cr superalloy SO ACTA MATERIALIA LA English DT Article DE nickel alloys; tungsten; nanostructure; coarsening; precipitation ID ELASTIC INTERACTION ENERGY; NICKEL-BASE SUPERALLOYS; ATOMIC-FORCE MICROSCOPY; MICROSTRUCTURAL DEVELOPMENT; ELECTRON-MICROSCOPY; COARSENING BEHAVIOR; RHENIUM ADDITION; MO ALLOYS; GAMMA'; NANOSTRUCTURE AB The effect of adding 2 at.% W to a model Ni-Al-Cr superalloy on the morphological evolution, spatial correlations and temporal evolution of gamma'(L1(2))-precipitates at 1073 K is studied with scanning electron microscopy and atomic force microscopy. Adding W yields a larger microhardness, earlier onset of spheroidal-to-cuboidal precipitate morphological transition, larger volume fraction (from similar to 20% to 30%), reduction in coarsening kinetics by one-third and a larger number density (N-v) of smaller mean radii (< R >) precipitates. The kinetics of (R) and interfacial area per unit volume obey t(1/3) and t-(1/3) relationships, respectively, which is consistent with coarsening driven by interfacial energy reduction. The N-v power-law dependencies deviate, however, from model predictions, indicating that a stationary state is not achieved. Quantitative analyses with precipitate size distributions, pair correlation functions and edge-to-edge interprecipitate distance distributions give insight into two-dimensional microstructural evolution, including the elastically driven transition from a uniform gamma'-distribution to one-dimensional < 001 >-strings to eventually clustered packs Of gamma'-precipitates in the less densely packed Ni-Al-Cr alloy. (c) 2007 Acta Materialia, Inc. Published by Elsevier Ltd. All rights reserved. C1 [Sudbrack, Chantal K.; Ziebell, Tiffany D.; Seidman, David N.] Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. [Sudbrack, Chantal K.] Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. [Ziebell, Tiffany D.] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. [Noebe, Ronald D.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. [Seidman, David N.] Northwestern Univ, Ctr Atom Probe Tomog, Evanston, IL 60208 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, 2220 Campus Dr, Evanston, IL 60208 USA. EM d-seidman@northwestern.edu RI Seidman, David/B-6697-2009 NR 57 TC 28 Z9 28 U1 0 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 2008 VL 56 IS 3 BP 448 EP 463 DI 10.1016/j.actamat.2007.09.042 PG 16 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 260OZ UT WOS:000253020900016 ER PT J AU Hinrichsen, RL Kurtz, AG Wang, JT Belcastro, CM Parks, JL AF Hinrichsen, Ronald L. Kurtz, Alex G. Wang, John T. Belcastro, Christine M. Parks, Jeffrey L. TI Modeling projectile damage in transport aircraft wing structures SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 47th Structures, Structural Dynamics, and Materials Conference CY MAY 01-04, 2006 CL Newport, RI SP AIAA, ASME, ASCE, AHS, ASC AB The objective of this paper is to quantify the damage caused by a missile impacting aircraft structures, using computational simulations. A three-step approach was taken. The first step was to investigate the effects of a simple body-on-body impact on the aircraft's wing structure. The second step was to simulate the hydrodynamic ram effects due to a high-velocity projectile impacting and traveling through a fluid-filled wing box. The third step was to add an explosive to the projectile model to investigate the combined effects of the kinetic energy of the projectile, hydrodynamic ram, and the explosive blast at various locations and incident angles. This paper presents the results of these steps in which the LS-DYNA code was used for each of the simulations. Results are presented in terms of images of damages as well as area removed. C1 [Hinrichsen, Ronald L.] RHAMM Technol LLC, Bellbrook, OH 45305 USA. [Kurtz, Alex G.] Aerosp Survivabil & Safety Flight, Assessment Grp, Wright Patterson AFB, OH 45433 USA. [Wang, John T.; Belcastro, Christine M.] NASA, Langley Res Ctr, Computat Struct & Mat Branch, Hampton, VA 23681 USA. [Parks, Jeffrey L.] IIT, Chicago, IL 60616 USA. NR 5 TC 5 Z9 5 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2008 VL 46 IS 2 BP 328 EP 335 DI 10.2514/1.26374 PG 8 WC Engineering, Aerospace SC Engineering GA 257TZ UT WOS:000252822800005 ER PT J AU Hampton, RD Leamy, MJ Bryan, PJ Quraishi, N AF Hampton, R. David Leamy, Michael J. Bryan, Paul J. Quraishi, Naveed TI Deformation and flexibility equations for curved, end-loaded, planar elastica SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 41st Aerospace Sciences Meeting and Exhibit CY JAN 06-09, 2003 CL RENO, NV SP Amer Inst Aeronaut & Astronaut ID GEOMETRICALLY EXACT; COMPUTATIONAL ASPECTS; FINITE ROTATIONS; DYNAMIC ANALYSIS; FLEXIBLE BEAMS; MOTIONS; RODS; IMPLEMENTATION; FORMULATION; ELEMENTS AB The International Space Station relies on the active rack isolation system as the central component of an integrated, station-wide strategy to isolate microgravity space-science experiments. The isolation system uses electromechanical actuators to isolate an international standard payload rack from disturbances due to the motion of the station. Disturbances to microgravity experiments on isolated racks are transmitted primarily via the isolation-system power and vacuum umbilicals. Experimental tests indicate that these umbilicals resonate at frequencies outside the controller's bandwidth, at levels of potential concern for certain microgravity experiments. Reduction in the umbilical resonant frequencies could help to address this issue. Toward that end, this work documents the development and verification of static equations for the in-plane deflections and flexibilities of an idealized umbilical (thin, flexible, elastic, inextensible, prismatic cantilever beam) under endpoint, in-plane loading (inclined force and moment). Gravity is neglected due to the on-orbit application. The analysis assumes that the umbilical experiences large static deflections from a reference curve describing its relaxed configuration, for which the slope follows a quadratic function of arc length. The treatment is applicable to the power and vacuum umbilicals, under the indicated assumptions. C1 [Hampton, R. David] US Mil Acad, Dept Civil Engn & Mech, West Point, NY 10996 USA. [Leamy, Michael J.] Mitre Corp, Emerging Technol Off, Mclean, VA 22102 USA. [Bryan, Paul J.] United Def, Dept Engn, Louisville, KY 40214 USA. [Quraishi, Naveed] NASA, Lyndon B Johnson Space Ctr, Int Space Stn Payloads Off, Act Rack Isolat Syst Int Space Stn Characterizat, Houston, TX 77058 USA. RP Hampton, RD (reprint author), US Mil Acad, Dept Civil Engn & Mech, West Point, NY 10996 USA. NR 37 TC 0 Z9 0 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2008 VL 46 IS 2 BP 356 EP 363 DI 10.2514/1.18467 PG 8 WC Engineering, Aerospace SC Engineering GA 257TZ UT WOS:000252822800007 ER PT J AU Crespo, LG Giesy, DP Kenny, SP AF Crespo, Luis G. Giesy, Daniel P. Kenny, Sean P. TI Robustness analysis and robust design of uncertain systems SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/ISSMO 11th Multidisciplinary Analysis and Optimization Conference CY SEP 06-08, 2006 CL Portsmouth, VA SP Amer Inst Aeronaut & Astronaut, ISSMO ID RELIABILITY-ANALYSIS; OPTIMIZATION; ALGORITHM AB This paper proposes a methodology for the analysis and design of systems subject to parametric uncertainty in which design requirements are specified via hard inequality constraints. Hard constraints are those that must be satisfied for all parameter realizations within a given uncertainty model. Uncertainty models given by norm-bounded perturbations from a nominal parameter value (i.e., hyperspheres) and by sets of independently bounded uncertain variables (i.e., hyperrectangles) are the focus of this paper. These models, which are also quite practical, allow for a rigorous mathematical treatment within the proposed framework. Hard-constraint feasibility is determined by sizing the largest uncertainty set for which the design requirements are satisfied. Assessments of robustness are attained by comparing this set with the actual uncertainty Model. These assessments do not suffer from the numerical deficiencies of sampling-based methods. Strategies that enable the comparison of the robustness characteristics of competing design alternatives, the approximation of the robust design space, and the systematic search for designs with improved robustness are also proposed. Because the problem formulation is generic and the tools derived only require standard optimization algorithms for their implementation, this methodology is applicable to a broad range of engineering problems. C1 [Crespo, Luis G.] Natl Inst Aerosp, Hampton, VA 23666 USA. [Giesy, Daniel P.; Kenny, Sean P.] NASA, Langley Res Ctr, Dynam Syst & Control Branch, Res & Technol Directorate, Hampton, VA 23681 USA. EM Luis.G.Crespo@nasa.gov; Daniel.P.Giesv@nasa.gov; Sean.P.Kenny@nasa.gov NR 26 TC 16 Z9 16 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2008 VL 46 IS 2 BP 388 EP 396 DI 10.2514/1.28683 PG 9 WC Engineering, Aerospace SC Engineering GA 257TZ UT WOS:000252822800010 ER PT J AU Osman, S Peeters, Z La Duc, MT Mancinelli, R Ehrenfreund, P Venkateswaran, K AF Osman, Shariff Peeters, Zan La Duc, Myron T. Mancinelli, Rocco Ehrenfreund, Pascale Venkateswaran, Kasthuri TI Effect of shadowing on survival of bacteria under conditions simulating the Martian atmosphere and UV radiation SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SPACECRAFT-ASSEMBLY FACILITY; LONG-TERM STARVATION; MICROBIAL DIVERSITY; BACILLUS-SUBTILIS; SPHERICAL CELLS; RIBOSOMAL-RNA; MARS; SPORES; ENVIRONMENTS; MICROORGANISMS AB Spacecraft-associated spores and four non-spore-forming bacterial isolates were prepared in Atacama Desert soil suspensions and tested both in solution and in a desiccated state to elucidate the shadowing effect of soil particulates on bacterial survival under simulated Martian atmospheric and UV irradiation conditions. All non-spore-forming cells that were prepared in nutrient-depleted, 0.2-mu m-filtered desert soil (DSE) microcosms and desiccated for 75 days on aluminum died, whereas cells prepared similarly in 60-mu m-filtered desert soil (DS) microcosms survived such conditions. Among the bacterial cells tested, Microbacterium schleiferi and Arthrobacter sp. exhibited elevated resistance to 254-nm UV irradiation (low-pressure Hg lamp), and their survival indices were comparable to those of DS- and DSE-associated Bacillus pumilus spores. Desiccated DSE-associated spores survived exposure to full Martian UV irradiation (200 to 400 nm) for 5 min and were only slightly affected by Martian atmospheric conditions in the absence of UV irradiation. Although prolonged UV irradiation (5 min to 12 h) killed substantial portions of the spores in DSE microcosms (similar to 5- to 6-log reduction with Martian UV irradiation), dramatic survival of spores was apparent in DS-spore microcosms. The survival of soil-associated wild-type spores under Martian conditions could have repercussions for forward contamination of extraterrestrial environments, especially Mars. C1 [Osman, Shariff; La Duc, Myron T.; Venkateswaran, Kasthuri] CALTECH, Jet Propuls Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. [Peeters, Zan; Ehrenfreund, Pascale] Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. [Mancinelli, Rocco] Carl Sagan Ctr, SETI Inst, Mountain View, CA 94043 USA. RP Venkateswaran, K (reprint author), CALTECH, Jet Propuls Lab, Biotechnol & Planetary Protect Grp, Mail Stop 89,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kjvenkat@jpl.nasa.gov NR 50 TC 45 Z9 45 U1 0 U2 14 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD FEB PY 2008 VL 74 IS 4 BP 959 EP 970 DI 10.1128/AEM.01973-07 PG 12 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 263MP UT WOS:000253221500005 PM 18083857 ER PT J AU Perronnet, M Jullien, M Villieras, F Raynal, J Bonnin, D Bruno, G AF Perronnet, Murielle Jullien, Michel Villieras, Frederic Raynal, Joel Bonnin, Dominique Bruno, Gerard TI Evidence of a critical content in Fe(0) on FoCa7 bentonite reactivity at 80 degrees C SO APPLIED CLAY SCIENCE LA English DT Article DE bentonite; smectite; metallic iron; iron-clay mass ratio; CEC; 7 angstrom Fe-rich clays ID CM CARBONACEOUS CHONDRITES; AQUEOUS ALTERATION; FE; CHLORITE; BERTHIERINE; SMECTITE; IRON; TRANSFORMATION; DISSOLUTION; SANDSTONES AB In order to assess the evolution of the confinement properties of clay engineered barriers (EBS) when in contact with metallic canisters containing radioactive wastes, Fe(0)-bentonite interactions need to be assessed. "45 days-80 degrees C" tests were performed using powdered FoCa7 bentonite and metallic iron. Since one fundamental parameter may be the available quantity of Fe(0), a wide range of Iron/Clay mass ratios (I/C) from 0 to 1/3 is used. The confinement power of clay material results from the swelling properties and the retention capacity. Thus, the major criterion which is chosen to assess the evolution of the confinement properties in this study is the variation of Cation Exchange Capacity (CEC). In parallel, the physico-chemical evolution of bentonite is studied using XRD and EDS-TEM microanalyses. The evolution of the distribution of iron environments is obtained by Fe-57 Mossbauer spectroscopy. This study evidences that both kaolinite and smectite from the bentonite are altered into SiAlFe gels when in contact with Fe(0). These gels maturates into Fe-rich di-trioctahedral phyllosilicates, whose composition is bounded by the one of odinite and greenalite in a Fe-M+-4Si diagram when I/C=1/3. Most of all, it is evidenced that the reaction depends on the available quantity of Fe(0). When the I/C ratio is between 1/30 and 1/7.5, the exchange capacity of FoCa7 bentonite starts decreasing, the consumption of Fe(0) becomes significant, the alteration of smectites occurs and secondary oxides are formed. The crystallization of Fe-rich phyllosilicates is observable when I/C ratio is higher, from a threshold between 1/7.5 and 1/5. Above I/C=1/3.75, initial iron oxides are strongly consumed and participate in the incorporation of Fe2+ and Fe3+ in gels or new phyllosilicates octahedra. These experimental results were used as input data for the prediction of the long-term evolution of the EBS using Crunch reaction-transport model. (C) 2007 Elsevier B.V. All rights reserved. C1 [Perronnet, Murielle] NASA, Lyndon B Johnson Space Ctr, KT, Houston, TX 77058 USA. [Perronnet, Murielle; Villieras, Frederic] Nancy Univ, CNRS, Ecole Natl Super Geol, Lab Environm & Mineralurgie,UMR 7569, F-54501 Vandoeuvre Les Nancy, France. [Perronnet, Murielle; Jullien, Michel; Raynal, Joel] Ctr Cadarache, Lab Modelisat Transferts Environm Commissariat En, F-13108 St Paul Les Durance, France. [Bonnin, Dominique] Ecole Natl Super Phys Chim Ind Paris, Phys Quant Lab, F-75231 Paris 05, France. [Bruno, Gerard] Inst Radioproctect & Surete Nucl, Serv Surete Dechets Radioactifs DSU SSD, F-92262 Fontenay Aux Roses, France. RP Perronnet, M (reprint author), NASA, Lyndon B Johnson Space Ctr, KT, 2101 Nasa Rd 1,Bldg 31 Room 236, Houston, TX 77058 USA. EM murielle.c.perronnet@nasa.gov RI Villieras, Frederic/E-1394-2011 OI Villieras, Frederic/0000-0002-9005-1009 NR 44 TC 23 Z9 23 U1 0 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-1317 J9 APPL CLAY SCI JI Appl. Clay Sci. PD FEB PY 2008 VL 38 IS 3-4 BP 187 EP 202 DI 10.1016/j.clay.2007.03.002 PG 16 WC Chemistry, Physical; Materials Science, Multidisciplinary; Mineralogy SC Chemistry; Materials Science; Mineralogy GA 270SQ UT WOS:000253740900004 ER PT J AU Inada, N Oguri, M Becker, RH Shin, MS Richards, GT Hennawi, JF White, RL Pindor, B Strauss, MA Kochanek, CS Johnston, DE Gregg, MD Kayo, I Eisenstein, D Hall, PB Castander, FJ Clocchiatti, A Anderson, SF Schneider, DP York, DG Lupton, R Chiu, K Kawano, Y Scranton, R Frieman, JA Keeton, CR Morokuma, T Rix, HW Turner, EL Burles, S Brunner, RJ Sheldon, ES Bahcall, NA Masataka, F AF Inada, Naohisa Oguri, Masamune Becker, Robert H. Shin, Min-Su Richards, Gordon T. Hennawi, Joseph F. White, Richard L. Pindor, Bartosz Strauss, Michael A. Kochanek, Christopher S. Johnston, David E. Gregg, Michael D. Kayo, Issha Eisenstein, Daniel Hall, Patrick B. Castander, Francisco J. Clocchiatti, Alejandro Anderson, Scott F. Schneider, Donald P. York, Donald G. Lupton, Robert Chiu, Kuenley Kawano, Yozo Scranton, Ryan Frieman, Joshua A. Keeton, Charles R. Morokuma, Tomoki Rix, Hans-Walter Turner, Edwin L. Burles, Scott Brunner, Robert J. Sheldon, Erin Scott Bahcall, Neta A. Masataka, Fukugita TI The Sloan Digital Sky Survey Quasar Lens Search. II. Statistical lens sample from the third data release SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; gravitational lensing; quasars : general ID 5TH DATA RELEASE; GRAVITATIONAL LENS; IMAGE SEPARATION; CANDIDATE SELECTION; LUMINOSITY FUNCTION; BINARY QUASARS; DARK ENERGY; DISCOVERY; CATALOG; CONSTRAINTS AB We report the first results of our systematic search for strongly lensed quasars using the spectroscopically confirmed quasars in the Sloan Digital Sky Survey (SDSS). Among 46,420 quasars from the SDSS Data Release 3 (similar to 4188 deg(2)), we select a subsample of 22,683 quasars that are located at redshifts between 0.6 and 2.2 and are brighter than the Galactic extinction-corrected i-band magnitude of 19.1. We identify 220 lens candidates from the quasar subsample, for which we conduct extensive and systematic follow-up observations in optical and near-infrared wavebands, in order to construct a complete lensed quasar sample at image separations between 1 '' and 20 '' and flux ratios of faint to bright lensed images larger than 10(-0.5). We construct a statistical sample of 11 lensed quasars. Ten of these are galaxy-scale lenses with small image separations (similar to 1 ''-2 '') and one is a large separation (15 '') system which is produced by a massive cluster of galaxies, representing the first statistical sample of lensed quasars including both galaxy- and cluster-scale lenses. The Data Release 3 spectroscopic quasars contain an additional 11 lensed quasars outside the statistical sample. C1 [Inada, Naohisa] RIKEN, Phys & Chem Res Organ, Cosm Radiat Lab, Wako, Saitama 3510015, Japan. [Inada, Naohisa] Univ Tokyo, Fac Sci, Inst Astron, Tokyo 1810015, Japan. [Oguri, Masamune] Stanford Univ, Kavli Inst Particle Astrophys & Cosmol, Menlo Pk, CA 94025 USA. [Oguri, Masamune; Shin, Min-Su; Strauss, Michael A.; Lupton, Robert; Turner, Edwin L.; Bahcall, Neta A.] Princeton Univ Observ, Princeton, NJ 08544 USA. [Becker, Robert H.; Gregg, Michael D.] IGPP LLNL, Livermore, CA USA. [Becker, Robert H.; Gregg, Michael D.] Univ Calif Davis, Dept Phys, Davis, CA USA. [Richards, Gordon T.] Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA. [Hennawi, Joseph F.] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. [White, Richard L.] Space Telescope Sci Inst, Baltimore, MD 21218 USA. [Pindor, Bartosz] Univ Leicester, Space Res Ctr, Leicester, Leics, England. [Kochanek, Christopher S.] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. [Johnston, David E.] Jet Propuls Lab, Pasadena, CA 91109 USA. [Johnston, David E.] CALTECH, Pasadena, CA 91125 USA. [Kayo, Issha; Kawano, Yozo] Nagoya Univ, Dept Phys & Astron, Chikusa Ku, Nagoya, Aichi 4648062, Japan. [Eisenstein, Daniel] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Hall, Patrick B.] York Univ, Dept Phys & Astron, N York, ON M3J 1P3, Canada. [Castander, Francisco J.] CSIC, Inst Estud Espacials Catalunya, Barcelona 08034, Spain. [Clocchiatti, Alejandro] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. [Anderson, Scott F.] Univ Washington, Dept Astron, Seattle, WA 98195 USA. [Schneider, Donald P.] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. [York, Donald G.] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. [York, Donald G.; Frieman, Joshua A.] Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. [Chiu, Kuenley] Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, England. [Scranton, Ryan] Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. [Frieman, Joshua A.] Ctr Particle Astrophys, Fermilab, Batavia, IL 60510 USA. [Frieman, Joshua A.] Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. [Keeton, Charles R.] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. [Morokuma, Tomoki] Natl Astron Observ, Tokyo 1818588, Japan. [Rix, Hans-Walter] Max Planck Inst Astron, D-69117 Heidelberg, Germany. [Burles, Scott] MIT, Dept Phys, Cambridge, MA 02139 USA. [Burles, Scott] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. [Brunner, Robert J.] Univ Illinois, Dept Astron, Urbana, IL 61801 USA. [Sheldon, Erin Scott] NYU, Dept Phys, Ctr Cosmol & Particle Phys, New York, NY 10003 USA. [Masataka, Fukugita] Univ Tokyo, Inst Cosm Ray Res, Chiba 2778582, Japan. RP Inada, N (reprint author), RIKEN, Phys & Chem Res Organ, Cosm Radiat Lab, 2-1 Hirosawa, Wako, Saitama 3510015, Japan. RI Oguri, Masamune/C-6230-2011; White, Richard/A-8143-2012; Turner, Edwin/A-4295-2011; Kayo, Issha/A-4389-2011 OI PINDOR, BARTOSZ/0000-0003-3240-2437; NR 74 TC 54 Z9 54 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2008 VL 135 IS 2 BP 496 EP 511 DI 10.1088/0004-6256/135/2/496 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 260VY UT WOS:000253039700004 ER PT J AU Oguri, M Inada, N Strauss, MA Kochanek, CS Richards, GT Schneider, DP Becker, RH Fukugita, M Gregg, MD Hall, PB Hennawi, JF Johnston, DE Kayo, I Keeton, CR Pindor, B Shin, MS Turner, EL White, RL York, DG Anderson, SF Bahcall, NA Brunner, RJ Burles, S Castander, FJ Chiu, K Clocchiatti, A Eisenstein, D Frieman, JA Kawano, Y Lupton, R Morokuma, T Rix, HW Scranton, R Sheldon, ES AF Oguri, Masamune Inada, Naohisa Strauss, Michael A. Kochanek, Christopher S. Richards, Gordon T. Schneider, Donald P. Becker, Robert H. Fukugita, Masataka Gregg, Michael D. Hall, Patrick B. Hennawi, Joseph F. Johnston, David E. Kayo, Issha Keeton, Charles R. Pindor, Bartosz Shin, Min-Su Turner, Edwin L. White, Richard L. York, Donald G. Anderson, Scott F. Bahcall, Neta A. Brunner, Robert J. Burles, Scott Castander, Francisco J. Chiu, Kuenley Clocchiatti, Alejandro Eisenstein, Daniel Frieman, Joshua A. Kawano, Yozo Lupton, Robert Morokuma, Tomoki Rix, Hans-Walter Scranton, Ryan Sheldon, Erin Scott TI The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on dark energy from the third data release quasar lens catalog SO ASTRONOMICAL JOURNAL LA English DT Review DE cosmological parameters; cosmology : theory; gravitational lensing ID EARLY-TYPE GALAXIES; MICROWAVE BACKGROUND-RADIATION; IMAGE SEPARATION DISTRIBUTION; VELOCITY DISPERSION FUNCTION; PROBE WMAP OBSERVATIONS; N-BODY SIMULATIONS; GRAVITATIONAL LENS; LUMINOSITY FUNCTION; COSMOLOGICAL CONSTANT; REDSHIFT SURVEY AB We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function, we compute the expected number of quasars lensed by early-type galaxies and their image separation distribution assuming a flat universe, which is then compared with seven lenses found in the SDSS Data Release 3 to derive constraints on dark energy under strictly controlled criteria. For a cosmological constant model (w = - 1) we obtain Omega = 0.74(-0.15)(+0.11) (stat.)(-0.06)(+0.13) (syst.). Allowing w to be a free parameter we find Omega(M) = 0.26(-0.06)(+0.07) (stat.)(-0.05)(+0.03) (syst.) and w = - 1.1 +/- 0.6(stat.)(-0.5)(+0.3) (syst.) when combined with the constraint from the measurement of baryon acoustic oscillations in the SDSS luminous red galaxy sample. Our results are in good agreement with earlier lensing constraints obtained using radio lenses, and provide additional confirmation of the presence of dark energy consistent with a cosmological constant, derived independently of type Ia supernovae. C1 [Oguri, Masamune] Stanford Univ, Kavli Inst Particle Astrophys Cosmol, Menlo Pk, CA 94025 USA. [Oguri, Masamune; Strauss, Michael A.; Shin, Min-Su; Turner, Edwin L.; Bahcall, Neta A.; Lupton, Robert] Princeton Univ Observ, Princeton, NJ 08544 USA. [Inada, Naohisa] Univ Tokyo, Fac Sci, Inst Astron, Tokyo 1810015, Japan. [Inada, Naohisa] RIKEN, Cosm Radiat Lab, Phys & Chem Res Organ, Wako, Saitama 3510198, Japan. [Strauss, Michael A.] Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. [Richards, Gordon T.] Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA. [Schneider, Donald P.] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. [Becker, Robert H.; Gregg, Michael D.] IGPP LLNL, Livermore, CA 94550 USA. [Becker, Robert H.; Gregg, Michael D.] Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. [Fukugita, Masataka] Univ Tokyo, Inst Cosm Ray Res, Chiba 2778582, Japan. [Hall, Patrick B.] York Univ, Dept Phys & Astron, N York, ON M3J 1P3, Canada. [Hennawi, Joseph F.] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. [Johnston, David E.] Jet Propuls Lab, Pasadena, CA 91109 USA. [Johnston, David E.] CALTECH, Pasadena, CA 91125 USA. [Kayo, Issha; Kawano, Yozo] Nagoya Univ, Dept Phys & Astrophys, Nagoya, Aichi 4648602, Japan. [Keeton, Charles R.] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. [Pindor, Bartosz] Univ Leicester, Space Res Ctr, Leicester LE1 7RH, Leics, England. [White, Richard L.] Space Telescope Sci Inst, Baltimore, MD 21218 USA. [York, Donald G.; Frieman, Joshua A.] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. [York, Donald G.; Frieman, Joshua A.] Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. [Anderson, Scott F.] Univ Washington, Dept Astron, Seattle, WA 98195 USA. [Brunner, Robert J.] Univ Illinois, Dept Astron, Urbana, IL 61801 USA. [Burles, Scott] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. [Burles, Scott] MIT, Dept Phys, Cambridge, MA 02139 USA. [Castander, Francisco J.] CSIC, Inst Estud Espacials Catalunya, Barcelona 08034, Spain. [Chiu, Kuenley] Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, England. [Clocchiatti, Alejandro] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. [Eisenstein, Daniel] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Frieman, Joshua A.] Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. [Frieman, Joshua A.] Ctr Partical Astrophys, Fermilab, Batavia, IL 60510 USA. [Morokuma, Tomoki] Natl Astron Observ, Tokyo 1818588, Japan. [Rix, Hans-Walter] Max Planck Inst Astron, D-69117 Heidelberg, Germany. [Scranton, Ryan] Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. [Sheldon, Erin Scott] NYU, Dept Phys, Ctr Cosmol & Particle Phys, New York, NY 10003 USA. RP Oguri, M (reprint author), Stanford Univ, Kavli Inst Particle Astrophys Cosmol, Menlo Pk, CA 94025 USA. RI Oguri, Masamune/C-6230-2011; Turner, Edwin/A-4295-2011; Kayo, Issha/A-4389-2011; White, Richard/A-8143-2012; OI PINDOR, BARTOSZ/0000-0003-3240-2437 NR 119 TC 59 Z9 59 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2008 VL 135 IS 2 BP 512 EP 519 DI 10.1088/0004-6256/135/2/512 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 260VY UT WOS:000253039700005 ER PT J AU De Mello, DF Smith, LJ Sabbi, E Gallagher, JS Mountain, M Harbeck, DR AF De Mello, D. F. Smith, L. J. Sabbi, E. Gallagher, J. S. Mountain, M. Harbeck, D. R. TI Star formation in the HI bridge between M81 and M82 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : general; galaxies : individual (M81, M82); galaxies : interactions ID MAGELLANIC BRIDGE; NEUTRAL-HYDROGEN; INTERACTING GALAXIES; TIDAL TAILS; STELLAR POPULATIONS; EVOLUTIONARY SEQUENCES; RADIATIVE OPACITIES; ADVANCED CAMERA; KINEMATICS; PERFORMANCE AB We present multiwavelength observations of stellar features in the Hi tidal bridge connecting M81 and M82 in the region called Arp's loop. We identify eight young star-forming regions from Galaxy Evolution Explorer ultraviolet ( UV) observations. Four of these objects are also detected at Ha. We determine the basic star-formation history of Arp's loop using F475W and F814W images obtained with the Advanced Camera for Surveys on board the Hubble Space Telescope. We find both a young (< 10 Myr) and an old (> 1 Gyr) stellar population with a similar spatial distribution and a metallicity Z similar to 0.004. We suggest that the old stellar population was formed in the stellar disk of M82 and/or M81 and ejected into the intergalactic medium during a tidal passage (similar to 200-300 Myr ago), whereas the young UV-bright stars have formed in the tidal debris. The UV luminosities of the eight objects are modest and typical of small clusters or OB associations. The tidal bridge between M81 and M82 therefore appears to be intermediate between the very low levels of star formation seen in the Magellanic bridge and actively star-forming tidal tails associated with major galaxy mergers. C1 [De Mello, D. F.] Goddard Space Flight Ctr, Observ Cosmol Lab, Greenbelt, MD 20771 USA. [De Mello, D. F.] Catholic Univ Amer, Washington, DC 20064 USA. [De Mello, D. F.] Johns Hopkins Univ, Baltimore, MD 21218 USA. [Smith, L. J.; Sabbi, E.; Mountain, M.] Space Telescope Sci Inst, Baltimore, MD 21218 USA. [Smith, L. J.] ESA, Space Telescope Operat Div, Baltimore, MD 21218 USA. [Smith, L. J.] UCL, Dept Phys & Astron, London WC1E 6BT, England. [Gallagher, J. S.; Harbeck, D. R.] Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. RP De Mello, DF (reprint author), Goddard Space Flight Ctr, Observ Cosmol Lab, Code 665, Greenbelt, MD 20771 USA. NR 53 TC 46 Z9 46 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2008 VL 135 IS 2 BP 548 EP 554 DI 10.1088/0004-6256/135/2/548 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 260VY UT WOS:000253039700009 ER PT J AU Carvano, JM Barucci, MA Delbo, M Fornasier, S Lowry, S Fitzsimmons, A AF Carvano, J. M. Barucci, M. A. Delbo, M. Fornasier, S. Lowry, S. Fitzsimmons, A. TI Surface properties of Rosetta's targets (21) Lutetia and (2867) Steins from ESO observations SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE minor planets; asteroids; infrared : solar system ID M-CLASS ASTEROIDS; PHYSICAL-PROPERTIES; MAINBELT ASTEROIDS; RADAR OBSERVATIONS; PHOTOMETRIC DATA; MISSION; POLARIZATION; 2867-STEINS; 21-LUTETIA; PLANETS AB Aims. The aim of this work is to constrain the size, composition and surface properties of asteroids (2867) Steins and (21) Lutetia, targets of the Rosetta mission. Rosetta is en route to rendezvous with comet 67P/Churyumov-Gerasimenko. Methods. Thermal-Infrared N-band observations for Lutetia and Steins were obtained using, respectively, TIMMI2 on the ESO 3.6-m telescope at La Silla and VISIR at the UT3 VLT telescope on Cerro Paranal; visible light curves for Steins were obtained using NTT+SUSI2, while R-band photometry for Lutetia was obtained with the 2.0-m Faulkes Telescope North on Haleakala. For Steins, the NEATM model was used to constrain its visible geometric albedo and beaming parameter. A detailed thermophysical model was implemented and used to analyze our set of observations of Lutetia as well as previous reported measurements. Results. The visible photometry of Steins was used along with data from the literature to yield a slope parameter of G=0.32(-0.11)(+0.14). Problems during the observations led to the loss of measurements on two of the three N-band filters requested for Steins. Using the remaining data and the polarimetric albedo recently published, we were able to constrain the thermal beaming parameter as eta > 1.2, which is more similar to near-Earth asteroids and suggests either high thermal inertia or a very rough surface. For Lutetia, the best fit visible geometric albedo obtained with our model and the reported observation is p(nu)=0.129, significantly lower than that obtained if one applies the same model to previously reported measurements. The discrepancy cannot be explained solely by assuming inhomogeneities in the surface properties and we suggest that the most plausible explanation is the presence of one or more large craters on the northern hemisphere. For both sets of measurements, the implied single scattering albedo of Lutetia is compatible with laboratory measurements of carbonaceous chondrite meteorites. C1 [Carvano, J. M.] Observ Nacl COAA, BR-20921400 Rio De Janeiro, Brazil. [Carvano, J. M.; Barucci, M. A.; Fornasier, S.] Observ Paris, LESIA, F-92195 Meudon, France. [Delbo, M.] Observ Cote Azur, Lab Cassiopee, F-06034 Nice, France. [Fornasier, S.] Univ Paris 07, F-75221 Paris 05, France. [Lowry, S.; Fitzsimmons, A.] Queens Univ Belfast, Astrophys Res Ctr, Belfast BT7 1NN, Antrim, North Ireland. [Lowry, S.] NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Carvano, JM (reprint author), Observ Nacl COAA, Rua Gal Jose Cristino 77, BR-20921400 Rio De Janeiro, Brazil. EM carvano@on.br RI Ferreira Carvano, Jorge/I-4039-2016 OI Ferreira Carvano, Jorge/0000-0003-0670-639X NR 32 TC 19 Z9 19 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2008 VL 479 IS 1 BP 241 EP 248 DI 10.1051/0004-6361:20078053 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 259RZ UT WOS:000252958000031 ER PT J AU Murphy, GC Lery, T O'Sullivan, S Spicer, D Bacciotti, F Rosen, A AF Murphy, G. C. Lery, T. O'Sullivan, S. Spicer, D. Bacciotti, F. Rosen, A. TI Interacting jets from binary protostars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : Herbig-Haro objects; ISM : individual objects : LDN 1551 IRS 5; ISM : jets and outflows; stars : formation ID QUADRUPOLAR MOLECULAR OUTFLOW; HERBIG-HARO OBJECTS; HYPERBOLIC CONSERVATION-LAWS; STAR-FORMING REGIONS; BOW SHOCK-MODELS; STELLAR JETS; IMAGING SURVEY; PROTOSTELLAR JETS; L1551 IRS-5; RADIO JET AB Aims. We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. Conclusions. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets. C1 [Murphy, G. C.] Univ Grenoble 1, Astrophys Lab, CNRS, F-38041 Grenoble, France. [Lery, T.] European Sci Fdn, F-67080 Strasbourg, France. [O'Sullivan, S.] Univ Coll Dublin, Sch Math Sci, Dublin 4, Ireland. [Spicer, D.] NASA, Goddard Space Flight Ctr, Lab Solar & Space Phys, Greenbelt, MD 20771 USA. [Bacciotti, F.] INAF, Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. [Rosen, A.] Max Planck Inst Radioastron, D-53121 Bonn, Germany. RP Murphy, GC (reprint author), Univ Grenoble 1, Astrophys Lab, CNRS, BP 53, F-38041 Grenoble, France. EM Gareth.Murphy@obs.ujf-grenoble.fr; tlery@esf.org; stephen.osullivan@ucd.ie; daniel.s.spicer@nasa.gov; fran@arcetri.astro.it; arosen@mpifr-bonn.mpg.de RI O'Sullivan, Stephen/A-4012-2009; Murphy, Gareth/A-4789-2010; Lery, Thibaut/M-3380-2014; Lery, Thibaut/P-5626-2015; OI Murphy, Gareth/0000-0002-2785-3674; Lery, Thibaut/0000-0003-1290-6849; Lery, Thibaut/0000-0003-1290-6849; BACCIOTTI, FRANCESCA/0000-0001-5776-9476 NR 79 TC 11 Z9 11 U1 1 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2008 VL 478 IS 2 BP 453 EP 460 DI 10.1051/0004-6361:20078609 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256FL UT WOS:000252713000018 ER PT J AU Kuntz, KD Snowden, SL AF Kuntz, K. D. Snowden, S. L. TI The EPIC-MOS particle-induced background spectra SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE methods : data analysis; instrumentation : detectors; X-rays : general ID XMM-NEWTON; EMISSION AB Context. To analyze diffuse emission that fills the field of view, one must accurately characterize the instrumental backgrounds. For the XMM-Newton EPIC-MOS instrument these backgrounds include a temporally variable "quiescent" component, as well as the strongly variable soft proton contamination. Aims. We have characterized the spectral and spatial response of the EPIC-MOS detectors to these background components and have developed tools to remove these backgrounds from observations. Methods. The "quiescent" component was characterized using a combination of the filter-wheel-closed data and a database of unexposed-region data. The soft proton contamination was characterized by differencing images and spectra taken during flared and flare-free intervals. Results. After application of our modeled backgrounds, the differences between independent observations of the same region of blank sky are consistent with the statistical uncertainties except when there is clear spectral evidence of solar wind charge exchange emission. Using a large sample of blank sky data, we show that strong magnetospheric SWCX emission requires elevated solar wind fluxes; observations through the densest part of the magnetosheath are not necessarily strongly contaminated with SWCX emission. C1 [Kuntz, K. D.] Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, Baltimore, MD 21218 USA. [Snowden, S. L.] NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. RP Kuntz, KD (reprint author), Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, 3400 Charles St, Baltimore, MD 21218 USA. EM kuntz@pha.jhu.edu RI Snowden, Steven/D-5292-2012 NR 12 TC 111 Z9 111 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2008 VL 478 IS 2 BP 575 EP 596 DI 10.1051/0004-6361:20077912 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256FL UT WOS:000252713000032 ER PT J AU Snowden, SL Mushotzky, RF Kuntz, KD Davis, DS AF Snowden, S. L. Mushotzky, R. F. Kuntz, K. D. Davis, D. S. TI A catalog of galaxy clusters observed by XMM-Newton SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE X-rays : galaxies : clusters; methods : data analysis ID X-RAY-EMISSION; RADIAL TEMPERATURE PROFILES; COOLING FLOW CLUSTERS; M-T RELATION; ENTROPY PROFILES; NEARBY CLUSTERS; BACKGROUND MAPS; LOCAL BUBBLE; ROSAT SURVEY; MASS AB Aim. We present a uniform catalog of the images and radial profiles of the temperature, abundance, and brightness for 70 clusters of galaxies observed by XMM-Newton. Methods. We use a new "first principles" approach to the modeling and removal of the background components; the quiescent particle background, the cosmic diffuse emission, the soft proton contamination, and the solar wind charge exchange emission. Each of the background components demonstrate significant spectral variability, several have spatial distributions that are not described by the photon vignetting function, and all except for the cosmic diffuse emission are temporally variable. Because these backgrounds strongly affect the analysis of low surface brightness objects, we provide a detailed description our methods of identification, characterization, and removal. Results. We have applied these methods to a large collection of XMM-Newton observations of clusters of galaxies and present the resulting catalog. We find significant systematic differences between the Chandra and XMM-Newton temperatures. C1 [Snowden, S. L.; Mushotzky, R. F.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Kuntz, K. D.] Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, Baltimore, MD 21218 USA. [Davis, D. S.] Univ Maryland, Dept Phys, Baltimore, MD 21250 USA. [Davis, D. S.] NASA, Goddard Space Flight Ctr, CRESST, Greenbelt, MD 20771 USA. [Davis, D. S.] NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. RP Snowden, SL (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM steven.l.snowden@nasa.gov; richard.f.mushotzky@nasa.gov; kuntz@pha.jhu.edu; david.s.davis@nasa.gov RI Snowden, Steven/D-5292-2012 NR 62 TC 184 Z9 184 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2008 VL 478 IS 2 BP 615 EP 658 DI 10.1051/0004-6361:20077930 PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256FL UT WOS:000252713000035 ER PT J AU Gliozzi, M Foschini, L Sambruna, RM Tavecchio, F AF Gliozzi, M. Foschini, L. Sambruna, R. M. Tavecchio, F. TI The polyhedral nature of LINERs: an XMM-Newton view of LINERs in radio galaxies SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : nuclei; X-rays : galaxies; radio continuum : galaxies ID ACTIVE GALACTIC NUCLEI; TERM X-RAY; SUPERMASSIVE BLACK-HOLES; BL LACERTAE OBJECTS; FR-I; ENERGY-DISTRIBUTIONS; SPECTRAL VARIABILITY; SEYFERT-1 GALAXIES; OPTICAL NUCLEI; ACCRETION AB Aims. We investigate the origin of X-rays and the nature of accretion flow in 4 low-ionization nuclear emission-line regions (LINERs) hosted by radio galaxies, namely NGC 1692, PKS 0625-35, 3C 88, 3C 444, recently observed with XMM-Newton. Methods. We combine the results from the time-averaged spectral analysis with model-independent information from X-ray temporal and spectral variability analyses, and with additional broadband information (specifically from the UV band, covered by the Optical Monitor aboard XMM-Newton, and from archival radio data). Results. The values of the Eddington ratios L-bol/ L-Edd of our sample span 2 orders of magnitude ranging between similar to 1 x 10(-5) and 1 x 10(-3). The 4 AGN are adequately fitted by the same continuum model that comprises at least one thermal component (kT similar to 0.65-1.45 keV) and a partially absorbed power law, whose relative contribution and photon index vary substantially from source to source. NGC 1692 and PKS 0625-35 have fairly steep power-law components (Gamma similar to 2.5-2.9), perhaps indicative of synchrotron emission from the base of a jet. Conversely, the flat photon index derived for 3C 88 (Gamma similar to 1.1) may be indicative of a heavily absorbed object. Finally, the time-averaged spectral properties of 3C 444 (Gamma similar to 1.9 and an apparent line-like excess around 6.7 keV) are more in line with Seyfert-like objects. The temporal analysis reveals that PKS 0625-35 and 3C 88 are significantly variable in the soft (0.2-1 keV) energy band. PKS 0625-35 also shows suggestive evidence of spectral variability on timescales of months, with a spectral softening associated with the source brightening. NGC 1692 is only marginally variable in the soft band, whereas 3C 444 does not show significant variability on short timescales. The main findings from the broadband analysis can be summarized as follows: 1) 3C 444, PKS 0625-35, and NGC 1692 have alpha(OX) values consistent with the alpha(OX)-l(UV) correlation found by Ste. en et al. (2006, AJ, 131, 2826) for Seyfert-like objects. 2) No positive correlation is found between L-X and the inclination angle, suggesting that the X-ray emission is not beamed. 3) The values of the radio-loudness are inversely proportional to the Eddington ratio and locate our objects in between the "radio-loud" and "radio-quiet" branches in the R-l(UV) plane proposed by Maoz (2007, MNRAS, 377, 1696). C1 [Gliozzi, M.] George Mason Univ, Fairfax, VA 22030 USA. [Foschini, L.] INAF IASF Bologna, I-40129 Bologna, Italy. [Sambruna, R. M.] NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. [Tavecchio, F.] INAF Osservatorio Astro Brera, Milan, Italy. RP Gliozzi, M (reprint author), George Mason Univ, 4400 Univ Dr, Fairfax, VA 22030 USA. EM mario@physics.gmu.edu RI Foschini, Luigi/H-3833-2012 OI Foschini, Luigi/0000-0001-8678-0324 NR 72 TC 12 Z9 12 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2008 VL 478 IS 3 BP 723 EP 737 DI 10.1051/0004-6361:20078414 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256FN UT WOS:000252713200005 ER PT J AU Stecker, FW Hunter, SD Kniffen, DA AF Stecker, F. W. Hunter, S. D. Kniffen, D. A. TI The likely cause of the EGRET GeV anomaly and its implications SO ASTROPARTICLE PHYSICS LA English DT Article DE gamma-rays; background radiation ID GAMMA-RAY EMISSION; COSMIC-RAY; GALACTIC PLANE; DARK-MATTER; MILKY-WAY; DIFFUSE; SPECTRUM; CALIBRATION; RADIATION; PULSAR AB Analysis of data from the EGRET gamma-ray detector on the Compton Gamma Ray Observatory indicated an anomaly in the form of an excess diffuse galactic flux at GeV energies over that which was theoretically predicted. Various explanations for this anomaly have been put forth, including the invocation of supersymmetric dark matter annihilation. We reexamine these explanations here, including a new discussion of the possible systematic errors in the sensitivity determination of the EGRET detector. We conclude that the most likely explanation of the EGRET "GeV anomaly" was an error in the estimation of the EGRET sensitivity at energies above similar to 1 GeV. We give reasons why such a situation could have occured. We find evidence from our new all-sky analysis which is inconsistent with the assumption that the anomaly can be a signal of supersymmetric dark matter annihilation. We also reconfirm the original results of the EGRET team on the extragalactic gamma-ray background spectrum. There are important implications of our analysis for the upcoming gamma ray large area telescope (GLAST) mission. Published by Elsevier B.V. C1 [Stecker, F. W.; Hunter, S. D.; Kniffen, D. A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Kniffen, D. A.] Univ Space Res Assoc, Columbia, MD 21044 USA. RP Stecker, FW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM stecker@lheapop.gsfc.nasa.gov RI Hunter, Stanley/D-2942-2012; Stecker, Floyd/D-3169-2012 NR 31 TC 47 Z9 47 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 J9 ASTROPART PHYS JI Astropart Phys. PD FEB PY 2008 VL 29 IS 1 BP 25 EP 29 DI 10.1016/j.astropartphys.2007.11.002 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 271MS UT WOS:000253793100004 ER PT J AU Gallagher, SC Johnson, KE Hornschemeier, AE Charlton, JC Hibbard, JE AF Gallagher, S. C. Johnson, K. E. Hornschemeier, A. E. Charlton, J. C. Hibbard, J. E. TI The revealing dust: Mid-infrared activity in Hickson compact group galaxy nuclei SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : interactions; galaxies : nuclei; galaxies : starburst; infrared : galaxies ID SPECTRAL ENERGY-DISTRIBUTIONS; SPITZER-SPACE-TELESCOPE; DWARF SEYFERT NUCLEI; GALACTIC NUCLEI; NEARBY GALAXIES; CLUSTERS; POPULATION; EVOLUTION; CHANDRA; ULTRAVIOLET AB We present a sample of 46 galaxy nuclei from 12 nearby (z < 4500 km s(-1)) Hickson Compact Groups (HCGs) with a complete suite of 1-24 mu m 2MASS + Spitzer nuclear photometry. For all objects in the sample, blue emission from stellar photospheres dominates in the near-infrared through the 3.6 mu m IRAC band. Of 46 galaxy nuclei, 25 (54%) show red mid-infrared continua characteristic of hot dust powered by ongoing star formation and/or accretion onto a central black hole. We introduce alpha(IRAC), the spectral index of a power-law fit to the 4.5-8.0 mu m IRAC data, and demonstrate that it cleanly separates the mid-infrared-active and nonactive HCG nuclei. This parameter is more powerful for identifying low-to moderate-luminosity mid-infrared activity than other measures, which include data at rest-frame lambda < 3.6 mu m that may be dominated by stellar photospheric emission. While the HCG galaxies clearly have a bimodal distribution in this parameter space, a comparison sample from the Spitzer Nearby Galaxy Survey (SINGS) matched in J-band total galaxy luminosity is continuously distributed. A second diagnostic, the fraction of 24 mu m emission in excess of that expected from quiescent galaxies, f(24D), reveals an additional three nuclei to be active at 24 mu m. Comparing these two mid-infrared diagnostics of nuclear activity to optical spectroscopic identifications from the literature reveals some discrepancies, and we discuss the challenges of distinguishing the source of ionizing radiation in these and other lower luminosity systems. We find a significant correlation between the fraction of mid-infrared-active galaxies and the total H I mass in a group and investigate possible interpretations of these results in light of galaxy evolution in the highly interactive system of a compact group environment. C1 [Gallagher, S. C.] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90024 USA. [Johnson, K. E.] Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. [Johnson, K. E.; Hibbard, J. E.] Natl Radio Astron Observ, Charlottesville, VA USA. [Hornschemeier, A. E.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Charlton, J. C.] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Gallagher, SC (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90024 USA. EM sgall@astro.ucla.edu NR 40 TC 24 Z9 24 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 730 EP 741 DI 10.1086/524103 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300008 ER PT J AU Yong, D Lambert, DL Paulson, DB Carney, BW AF Yong, David Lambert, David L. Paulson, Diane B. Carney, Bruce W. TI Rubidium and lead abundances in giant stars of the globular clusters M4 and M5 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxy : abundances; globular clusters : individual (M4, M5); stars : abundances ID NEUTRON-CAPTURE ELEMENTS; METAL-POOR STARS; MASSIVE AGB EVOLUTION; CHEMICAL-COMPOSITION; BRIGHT GIANTS; BRANCH STARS; RED GIANTS; CYANOGEN DISTRIBUTION; GALACTIC ENRICHMENT; FULL COMPUTATION AB We present measurements of the neutron-capture elements Rb and Pb for bright giants in the globular clusters M4 and M5. The clusters are of similar metallicity ([Fe/ H] similar or equal to -1.2), but M4 is decidedly s-process enriched relative to M5: [Ba/Fe] = +0.6 for M4 but 0.0 for M5. The Rb and Pb abundances were derived by comparing synthetic spectra with high-resolution, high signal-to-noise ratio spectra obtained with MIKE on the Magellan Telescope. Abundances of Y, Zr, La, and Eu were also obtained. In M4, the mean abundances from 12 giants are [Rb/Fe] = 0.39 +/- 0.02 (sigma = 0.07), [Rb/Zr] = 0.17 +/- 0.03 (sigma = 0.08), and [Pb/Fe] = 0.30 +/- 0.02 (sigma = 0.07). In M5, the mean abundances from two giants are [Rb/Fe] = 0.00 +/- 0.05 (sigma = 0.06), [Rb/Zr] = 0.08 +/- 0: 08 (sigma = 0.11), and [Pb/Fe] = -0.35 +/- 0.02 (sigma = 0.04). Within the measurement uncertainties, the abundance ratios [Rb/Fe], [Pb/Fe], and [Rb/X] for X = Y, Zr, and La are constant from star to star in each cluster, and none of these ratios are correlated with O or Na abundances. While M4 has a higher Rb abundance than M5, the ratios [Rb/X] are similar in both clusters, indicating that the nature of the s-products is very similar for each cluster but the gas from which M4's stars formed had a higher concentration of these products. C1 [Yong, David] Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. [Lambert, David L.] Univ Texas Austin, WJ McDonald Observ, Austin, TX 78712 USA. [Paulson, Diane B.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Carney, Bruce W.] Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. RP Yong, D (reprint author), Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, Cotter Rd, Weston, ACT 2611, Australia. EM yong@mso.anu.edu.au; dll@astro.as.utexas.edu; diane.b.paulson@gsfc.nasa.gov; bruce@physics.unc.edu NR 84 TC 42 Z9 42 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 854 EP 863 DI 10.1086/524376 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300019 ER PT J AU Scargle, JD Norris, JP Bonnell, JT AF Scargle, Jeffrey D. Norris, Jay P. Bonnell, J. T. TI An algorithm for detecting quantum gravity photon dispersion in gamma-ray bursts: DisCan SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; methods : data analysis ID ENERGY; LIMITS; DURATION; EMISSION; SPEED; LIGHT; LAG AB DisCan is a new algorithm implementing photon dispersion cancellation in order to measure energy-dependent delays in variable sources. This method finds the amount of reversed dispersion that optimally cancels any actual dispersion present. It applies to any time- and energy-tagged photon data and avoids binning in both time and energy. The primary motivation here is the search for quantum gravity-based dispersion in future gamma-ray burst data from the Gamma-Ray Large Area Space Telescope ( GLAST). Extrapolation of what is known about bursts at lower energies yields a reasonable prospect that photon dispersion effects consistent with some quantum gravity formalisms may be detected in sufficiently bright bursts. Short bursts have no or very small inherent lags and are therefore better prospects than long ones, but even they suffer a systematic error due to pulse asymmetry that may yield an irreducible uncertainty. We note that observations at TeV energies and higher will be useful for detecting dispersion in GRBs, using this and other algorithms, only if energy resolution can be improved over what is currently achieved. C1 [Scargle, Jeffrey D.] NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. [Norris, Jay P.] NASA, Ames Res Ctr, Div Space Sci, Astrophys Branch, Moffett Field, CA 94035 USA. [Bonnell, J. T.] NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. RP Scargle, JD (reprint author), NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. NR 34 TC 22 Z9 22 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 972 EP 980 DI 10.1086/524396 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300027 ER PT J AU Dib, R Kaspi, VM Gavriil, FP AF Dib, Rim Kaspi, Victoria M. Gavriil, Fotis P. TI Glitches in anomalous X-ray pulsars SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (1E 1841-045, RXS J170849.0-400910); stars : neutron; X-rays : stars ID SOFT GAMMA REPEATERS; 1E 1048.1-5937; NEUTRON-STARS; VELA PULSAR; 1RXS J170849.0-400910; VORTEX CREEP; INTERNAL TEMPERATURE; INFRARED COUNTERPART; TRANSIENT MAGNETAR; XTE J1810-197 AB We report on 8.7 and 7.6 yr of Rossi X-Ray Timing Explorer (RXTE) observations of the anomalous X-ray pulsars (AXPs) RXS J170849.0 - 400910 and 1E 1841 - 045, respectively. These observations have allowed us to study the long-term timing, pulsed flux, and pulse profile evolution of these objects. We report on four new glitches, one from RXS J170849.0 - 400910 and three from 1E 1841 - 045. With nearly all known persistent AXPs now seen to glitch, such behavior is clearly generic to this source class. We show that in terms of fractional frequency change, AXPs are among the most actively glitching neutron stars, with glitch amplitudes in general larger than in radio pulsars. However, in terms of absolute glitch amplitude, AXP glitches are unremarkable. Unlike radio pulsar glitches, AXP glitches can sometimes, though not always, be accompanied by radiative events. We show that the largest observed AXP glitches have recoveries that are unusual among those of radio pulsar glitches, with the combination of recovery time scale and fraction yielding changes in spin-down rates following the glitch similar to, or larger than, the long-term average. We also observed a large long-term fractional increase in the magnitude of the spin-down rate of 1E 1841 - 045, following its largest glitch, with Delta(v)/(v) = 0.1. These observations are challenging to interpret in standard glitch models, as is the frequent occurence of large glitches given AXPs' high measured temperatures. We speculate that the stellar core may be involved in the largest AXP glitches. C1 [Dib, Rim; Kaspi, Victoria M.] McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. [Gavriil, Fotis P.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dib, R (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ H3A 2T8, Canada. NR 65 TC 82 Z9 82 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 1044 EP 1061 DI 10.1086/524653 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300034 ER PT J AU Yashiro, S Michalek, G Akiyama, S Gopalswamy, N Howard, RA AF Yashiro, S. Michalek, G. Akiyama, S. Gopalswamy, N. Howard, R. A. TI Spatial relationship between solar flares and coronal mass ejections SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : coronal mass ejections (CMEs); Sun : flares ID ENERGETIC PARTICLE EVENTS; LARGE-ANGLE; SHOCK; PROMINENCE AB We report on the spatial relationship between solar flares and coronal mass ejections (CMEs) observed during 1996-2005 inclusive. We identified 496 flare-CME pairs considering limb flares ( distance from central meridian >= 45 degrees) with soft X-ray flare size >= C3 level. The CMEs were detected by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO). We investigated the flare positions with respect to the CME span for the events with X-class, M-class, and C-class flares separately. It is found that the most frequent flare site is at the center of the CME span for all the three classes, but that frequency is different for the different classes. Many X-class flares often lie at the center of the associated CME, while C-class flares widely spread to the outside of the CME span. The former is different from previous studies, which concluded that no preferred flare site exists. We compared our result with the previous studies and conclude that the long-term LASCO observation enabled us to obtain the detailed spatial relation between flares and CMEs. Our finding calls for a closer flare-CME relationship and supports eruption models typified by the CSHKP magnetic reconnection model. C1 [Yashiro, S.; Michalek, G.; Akiyama, S.] Catholic Univ Amer, Washington, DC 20064 USA. [Yashiro, S.; Michalek, G.; Akiyama, S.; Gopalswamy, N.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Michalek, G.] Jagiellonian Univ, Astron Observ, PL-30244 Krakow, Poland. [Howard, R. A.] Naval Res Lab, Washington, DC 20375 USA. RP Yashiro, S (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. RI Gopalswamy, Nat/D-3659-2012; OI Gopalswamy, Nat/0000-0001-5894-9954 NR 27 TC 37 Z9 37 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 1174 EP 1180 DI 10.1086/524927 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300047 ER PT J AU Band, DL Grindlay, JE Hong, J Fishman, G Hartmann, DH Garson, A Krawczynski, H Barthelmy, S Gehrels, N Skinner, G AF Band, D. L. Grindlay, J. E. Hong, J. Fishman, G. Hartmann, D. H. Garson, A., III Krawczynski, H. Barthelmy, S. Gehrels, N. Skinner, G. TI Exist's gamma-ray burst sensitivity SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID BATSE OBSERVATIONS; ENERGY; SPECTRA AB We use semianalytic techniques to evaluate the burst sensitivity of designs for the EXIST hard X-ray survey mission. Applying these techniques to the mission design proposed for the Beyond Einstein program, we find that with its very large field of view and faint gamma-ray burst detection threshold, EXIST will detect and localize approximately two bursts per day, a large fraction of which may be at high redshift. We estimate that EXIST's maximum sensitivity will be similar to 4 times greater than that of Swift's Burst Alert Telescope. Bursts will be localized to better than 4000 at threshold, with a burst position as good as a few arcseconds for strong bursts. EXIST's combination of three different detector systems will provide spectra from 3 keV to more than 10MeV. Thus, EXIST will enable a major leap in the understanding of bursts, their evolution, environment, and utility as cosmological probes. C1 [Band, D. L.; Barthelmy, S.; Gehrels, N.; Skinner, G.] NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. [Band, D. L.; Skinner, G.] NASA, Goddard Space Flight Ctr, CRESST, Greenbelt, MD 20771 USA. [Band, D. L.] Univ Maryland, Ctr Space Sci & Technol, Baltimore, MD 21250 USA. [Grindlay, J. E.; Hong, J.] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. [Fishman, G.] NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35805 USA. [Hartmann, D. H.] Clemson Univ, Clemson, SC 29634 USA. [Garson, A., III; Krawczynski, H.] Washington Univ, St Louis, MO 63130 USA. [Skinner, G.] Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Band, DL (reprint author), NASA, Goddard Space Flight Ctr, CRESST, Code 661, Greenbelt, MD 20771 USA. EM david.l.band@nasa.gov RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012 NR 16 TC 10 Z9 10 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2008 VL 673 IS 2 BP 1225 EP 1232 DI 10.1086/524883 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RI UT WOS:000253454300054 ER PT J AU Meyer, MR Carpenter, JM Mamajek, EE Hillenbrand, LA Hollenbach, D Moro-Martin, A Kim, JS Silverstone, MD Najita, J Hines, DC Pascucci, I Stauffer, JR Bouwman, J Backman, DE AF Meyer, M. R. Carpenter, J. M. Mamajek, E. E. Hillenbrand, L. A. Hollenbach, D. Moro-Martin, A. Kim, J. S. Silverstone, M. D. Najita, J. Hines, D. C. Pascucci, I. Stauffer, J. R. Bouwman, J. Backman, D. E. TI Evolution of mid-infrared excess around sun-like stars: constraints on models of terrestrial planet formation SO ASTROPHYSICAL JOURNAL LETTERS LA English DT Article DE circumstellar matter; infrared : stars; planetary systems : formation ID SPITZER-SPACE-TELESCOPE; T-TAURI STARS; INFRARED ARRAY CAMERA; DEBRIS DISKS; SYSTEMS FEPS; DUST DISKS; MYR; DISCOVERY; PLEIADES; NEARBY AB We report observations from the Spitzer Space Telescope regarding the frequency of 24 mm excess emission toward Sun-like stars. Our unbiased sample is composed of 309 stars with masses 0.7-2.2 M-circle dot and ages from, < 3 Myr to > 3 Gyr that lack excess emission at wavelengths <= 8 mu m. We identify 30 stars that exhibit clear evidence of excess emission from the observed 24 mu m/8 mu m flux ratio. The implied 24 mu m excesses of these candidate debris disk systems range from 13% (the minimum detectable) to more than 100% compared to the expected photospheric emission. The frequency of systems with evidence for dust debris emitting at 24 mu m ranges from 8.5%-19% at ages < 300 Myr to < 4% for older stars. The results suggest that many, perhaps most, Sun-like stars might form terrestrial planets. C1 [Meyer, M. R.; Kim, J. S.; Silverstone, M. D.; Pascucci, I.] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Carpenter, J. M.; Hillenbrand, L. A.] CALTECH, Pasadena, CA 91125 USA. [Mamajek, E. E.] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. [Hollenbach, D.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Moro-Martin, A.] Princeton Univ, Princeton, NJ 08544 USA. [Najita, J.] Natl Opt Astron Observ, Tucson, AZ 85726 USA. [Hines, D. C.] Space Sci Inst, Boulder, CO USA. [Stauffer, J. R.] Spitzer Sci Ctr, Pasadena, CA USA. [Bouwman, J.] Max Planck Inst Astron, D-69117 Heidelberg, Germany. [Backman, D. E.] SETI Inst, Mountain View, CA USA. RP Meyer, MR (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM mmeyer@as.arizona.edu; jmc@astro.caltech.edu; emamajek@cfa.harvard.edu; lah@astro.caltech.edu; hollenbach@ism.arc.nasa.gov; amaya@astro.princeton.edu; serena@as.arizona.edu; msilverstone@as.arizona.edu; jnajita@noao.edu; hines@spacescience.org; pascucci@as.arizona.edu; stauffer@ipac.caltech.edu; bouwman@mpia.mpg.de; dbackman@mail.arc.nasa.gov NR 38 TC 73 Z9 73 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 2041-8205 J9 ASTROPHYS J LETT JI Astrophys. J. Lett. PD FEB 1 PY 2008 VL 673 IS 2 BP L181 EP L184 DI 10.1086/527470 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 291YI UT WOS:000255233000019 ER PT J AU Nuth, JA Johnson, NM Manning, S AF Nuth, Joseph A., III Johnson, Natasha M. Manning, Steven TI A self-perpetuating catalyst for the production of complex organic molecules in protostellar nebulae SO ASTROPHYSICAL JOURNAL LETTERS LA English DT Article DE astrobiology; astrochemistry; methods : laboratory; molecular processes; solar system : formation; stars : pre-main-sequence ID SOLAR NEBULA; CHEMISTRY; COMETS; ORIGIN; DUST; CO AB When hydrogen, nitrogen, and CO are exposed to amorphous iron silicate surfaces at temperatures between 500 and 900 K a carbonaceous coating forms via Fischer-Tropsch-type reactions. Under normal circumstances such a coating would impede or stop further reaction. However, we find that this coating is a better catalyst than the amorphous iron silicates that initiate these reactions. Formation of a self-perpetuating catalytic coating on grain surfaces could explain the rich deposits of macromolecular carbon found in primitive meteorites and would imply that protostellar nebulae should be rich in organic material. C1 [Nuth, Joseph A., III; Johnson, Natasha M.; Manning, Steven] NASA, Goddard Space Flight Ctr, Astrochem Lab, Greenbelt, MD 20771 USA. [Johnson, Natasha M.] NASA Headquarters, Washington, DC 20546 USA. [Manning, Steven] Univ Maryland, Goddard Ctr Astrobiol, College Pk, MD 20742 USA. [Manning, Steven] Univ Maryland, Dept Chem, College Pk, MD 20742 USA. RP Nuth, JA (reprint author), NASA, Goddard Space Flight Ctr, Astrochem Lab, Code 691, Greenbelt, MD 20771 USA. RI Johnson, Natasha/E-3093-2012; Nuth, Joseph/E-7085-2012 NR 18 TC 40 Z9 40 U1 1 U2 16 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 2041-8205 J9 ASTROPHYS J LETT JI Astrophys. J. Lett. PD FEB 1 PY 2008 VL 673 IS 2 BP L225 EP L228 DI 10.1086/528741 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 291YI UT WOS:000255233000029 ER PT J AU Mazzuca, LM Knapen, JH Veilleux, S Regan, MW AF Mazzuca, Lisa M. Knapen, Johan H. Veilleux, Sylvain Regan, Michael W. TI A connection between star formation in nuclear rings and their host galaxies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : spiral; galaxies : structure; stars : formation ID BARRED SPIRAL GALAXIES; DISK GALAXIES; MOLECULAR GAS; CENTRAL REGION; SECULAR EVOLUTION; M100; STARBURSTS; KINEMATICS; NGC-7469; CLUSTERS AB We present results from a photometric H alpha survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We find a clear relationship between the position angles and ellipticities of the rings and those of their host galaxies, which indicates the rings are in the same plane as the disk and circular. We use population synthesis models to estimate ages of each H alpha-emitting (H II) region, which range from 1 to 10 Myr throughout the rings. We find that approximately half of the rings contain azimuthal age gradients that encompass at least 25% of the ring, although there is no apparent relationship between the presence or absence of age gradients and the morphology of the rings or their host galaxies. NGC 1343, NGC 1530, and NGC 4321 show clear bipolar age gradients, where the youngest H II regions are located near the two contact points of the bar and ring. We speculate in these cases that the gradients are related to an increased mass inflow rate and/or an overall higher gas density in the ring, which would allow for massive star formation to occur on short timescales, after which the galactic rotation would transport the H II regions around the ring as they age. Two-thirds of the barred galaxies show correlation between the locations of the youngest H II region(s) in the ring and the location of the contact points, which is consistent with predictions from numerical modeling. C1 [Mazzuca, Lisa M.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Knapen, Johan H.] Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. [Knapen, Johan H.] Inst Astrofis Canarias, E-38200 San Cristobal la Laguna, Spain. [Veilleux, Sylvain] Univ Maryland, Dept Astron, College Pk, MD 20742 USA. [Regan, Michael W.] Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Mazzuca, LM (reprint author), NASA, Goddard Space Flight Ctr, Code 441, Greenbelt, MD 20771 USA. NR 62 TC 44 Z9 45 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2008 VL 174 IS 2 BP 337 EP 365 DI 10.1086/522338 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279GO UT WOS:000254343600004 ER PT J AU Plucinsky, PP Williams, B Long, KS Gaetz, TJ Sasaki, M Pietsch, W Tuellmann, R Smith, RK Blair, WP Helfand, D Hughes, JP Winkler, PF De Avillez, M Bianchi, L Breitschwerdt, D Edgar, RJ Ghavamian, P Grindlay, J Haberl, F Kirshner, R Kuntz, K Mazeh, T Pannuti, TG Shporer, A Thilker, DA AF Plucinsky, Paul P. Williams, Benjamin Long, Knox S. Gaetz, Terrance J. Sasaki, Manami Pietsch, Wolfgang Tuellmann, Ralph Smith, Randall K. Blair, William P. Helfand, David Hughes, John P. Winkler, P. Frank De Avillez, Miguel Bianchi, Luciana Breitschwerdt, Dieter Edgar, Richard J. Ghavamian, Parviz Grindlay, Jonathan Haberl, Frank Kirshner, Robert Kuntz, Kip Mazeh, Tsevi Pannuti, Thomas G. Shporer, Avi Thilker, David A. TI Chandra ACIS Survey of M33 (ChASeM33): A first look SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : individual (M33); supernova remnants; X-rays : galaxies ID X-RAY SOURCES; XMM-NEWTON SURVEY; SUPERNOVA REMNANT; GALAXY M33; H-I; SPECTROSCOPY; POPULATION; CANDIDATES; PHOTOMETRY; REGIONS AB We present an overview of the Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy. The 1.4Ms survey covers the galaxy out to R approximate to 180( approximate to 4 kpc). These data provide the most intensive, high spatial resolution assessment of the X-ray source populations available for the confused inner regions of M33. Mosaic images of the ChASeM33 observations show several hundred individual X-ray sources as well as soft diffuse emission from the hot interstellar medium. Bright, extended emission surrounds the nucleus and is also seen from the giant H II regions NGC 604 and IC 131. Fainter extended emission and numerous individual sources appear to trace the inner spiral structure. The initial source catalog, arising from similar to 2/3 of the expected survey data, includes 394 sources significant at the 3 sigma confidence level or greater, down to a limiting luminosity ( absorbed) of similar to 1: 6; 1035 ergs s(-1) (0.35-8.0 keV). The hardness ratios of the sources separate those with soft, thermal spectra such as supernova remnants from those with hard, nonthermal spectra such as X-ray binaries and background active galactic nuclei. Emission extended beyond the Chandra point-spread function is evident in 23 of the 394 sources. Cross-correlation of the ChASeM33 sources against previous catalogs of X-ray sources in M33 results in matches for the vast majority of the brighter sources and shows 28 ChASeM33 sources within 1000 of supernova remnants identified by prior optical and radio searches. This brings the total number of such associations to 31 out of 100 known supernova remnants in M33. C1 [Plucinsky, Paul P.; Gaetz, Terrance J.; Sasaki, Manami; Tuellmann, Ralph; Edgar, Richard J.; Grindlay, Jonathan; Kirshner, Robert] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. [Williams, Benjamin] Univ Washington, Dept Astron, Seattle, WA 98195 USA. [Long, Knox S.] Space Telescope Sci Inst, Baltimore, MD 21218 USA. [Pietsch, Wolfgang; Haberl, Frank] Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. [Smith, Randall K.; Blair, William P.; Ghavamian, Parviz; Kuntz, Kip; Thilker, David A.] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. [Smith, Randall K.; Kuntz, Kip] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Helfand, David] Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. [Hughes, John P.] Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. [Winkler, P. Frank] Middlebury Coll, Dept Phys, Middlebury, VT 05753 USA. [De Avillez, Miguel] Univ Evora, Dept Math, P-7000 Evora, Portugal. [Breitschwerdt, Dieter] Univ Vienna, Inst Astron, A-1180 Vienna, Austria. [Mazeh, Tsevi; Shporer, Avi] Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. [Pannuti, Thomas G.] Morehead State Univ, Ctr Space Sci, Morehead, KY 40351 USA. RP Plucinsky, PP (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM plucinsky@cfa.harvard.edu RI Sasaki, Manami/P-3045-2016; OI Sasaki, Manami/0000-0001-5302-1866; Haberl, Frank/0000-0002-0107-5237 NR 40 TC 28 Z9 28 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2008 VL 174 IS 2 BP 366 EP 378 DI 10.1086/522942 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279GO UT WOS:000254343600005 ER PT J AU Freedman, RS Marley, MS Lodders, K AF Freedman, Richard S. Marley, Mark S. Lodders, Katharina TI Line and mean opacities for ultracool dwarfs and extrasolar planets SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE line : profiles; molecular data; stars : atmospheres; stars : low-mass, brown dwarfs ID COLLISION-INDUCED ABSORPTION; ROBERT-BONAMY FORMALISM; BROWN DWARFS; INFRARED-ABSORPTION; ATMOSPHERIC CHEMISTRY; FUNDAMENTAL-BAND; GIANT PLANETS; MOLECULAR OPACITIES; CARBON-MONOXIDE; PARA-HYDROGEN AB Opacities and chemical abundance data are crucial ingredients of ultracool dwarf and extrasolar giant planet atmosphere models. We report here on the detailed sources of molecular opacity data employed by our group for this application. We also present tables of Rosseland and Planck mean opacities, which are of use in some studies of the atmospheres, interiors, and evolution of planets and brown dwarfs. For the tables presented here we have included the opacities of important atomic and molecular species, including the alkali elements, pressure-induced absorption by hydrogen, and other significant opacity sources, but we neglect opacity from condensates. We report for each species how we have assembled molecular line data from a combination of public databases, laboratory data that is not yet in the public databases, and our own numerical calculations. We combine these opacities with abundances computed from a chemical equilibrium model using recently revised solar abundances to compute mean opacities. The chemical equilibrium calculation accounts for the settling of condensates in a gravitational field and is applicable to ultracool dwarf and extrasolar planetary atmospheres, but not circumstellar disks. We find that the inclusion of alkali atomic opacity substantially increases the mean opacities over those currently in the literature at densities relevant to the atmospheres and interiors of giant planets and brown dwarfs. We provide our opacity tables for public use and discuss their limitations. C1 [Freedman, Richard S.; Marley, Mark S.] NASA, Ames Res Ctr, Moffett Field, CA 94305 USA. [Lodders, Katharina] Washington Univ, Dept Earth & Planetary Sci, Planetary Chem Lab, St Louis, MO 63130 USA. RP Freedman, RS (reprint author), NASA, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94305 USA. EM freedman@darkstar.arc.nasa.gov; lodders@wustl.edu RI Marley, Mark/I-4704-2013 NR 66 TC 182 Z9 182 U1 3 U2 13 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2008 VL 174 IS 2 BP 504 EP 513 DI 10.1086/521793 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 279GO UT WOS:000254343600012 ER PT J AU Stowe, RP Yetman, DL Storm, WF Sams, CF Pierson, DL AF Stowe, Raymond P. Yetman, Deborah L. Storm, William F. Sams, Clarence F. Pierson, Duane L. TI Neuroendocrine and immune responses to 16-day bed rest with realistic launch and landing G profiles SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE stress; microgravity; hypergravity; leukocyte trafficking ID SHORT-TERM SPACEFLIGHT; SPACE-FLIGHT; KAPPA-B; CD4(+) LYMPHOCYTES; PERIPHERAL-BLOOD; MISSION DURATION; IL-12 PRODUCTION; GLUCOCORTICOIDS; REACTIVATION; ASTRONAUTS AB Background: Spaceflight is associated with increased glucocorticoids and catecholamines, both well-known for their immunosuppressive effects. The objective of this study was to develop a model of spaceflight by using a human centrifuge to reproduce launch and landing G forces along with bed rest to simulate microgravity. Hypothesis: Acute changes in G forces are causal factors in neuroendocrine and immune changes. Methods: Ten subjects underwent realistic launch G-force profiles followed by 16 d of 6 degrees head-down tilt bed rest. At the end of the bed rest, subjects were subjected to realistic landing G-force profiles. Stress hormones and changes in leukocyte and lymphocyte subsets were measured in blood and urine samples over the course of the study. Results: Similar to shorter Shuttle missions (i.e., <= 9 d), plasma cortisol was significantly decreased at simulated landing while urinary epinephrine was significantly increased. Urinary cortisol was significantly increased after simulated launch. The pattern of leukocyte and lymphocyte changes also mirrored the changes found in shorter 9-d spaceflights. Conclusions: These data suggest a role for both catecholamines and glucocorticoids in mediating changes in leukocyte and lymphocyte subsets during simulated microgravity coupled with hypergravity. Our results were also strikingly similar to those from actual Shuttle missions and support our conclusion that we have developed a model of spaceflight. C1 [Stowe, Raymond P.; Yetman, Deborah L.] Microgen Labs, La Marque, TX 77568 USA. [Storm, William F.] NTI Inc, San Antonio, TX USA. [Sams, Clarence F.; Pierson, Duane L.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Stowe, RP (reprint author), Microgen Labs, 903 Texas Ave, La Marque, TX 77568 USA. EM rpstowe@microgenlabs.com NR 34 TC 12 Z9 12 U1 0 U2 4 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD FEB PY 2008 VL 79 IS 2 BP 117 EP 122 DI 10.3357/ASEM.2205.2008 PG 6 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 255AD UT WOS:000252628200007 PM 18309909 ER PT J AU Taylor, JP Smith, WL Cuomo, V Larar, AM Zhou, DK Serio, C Maestri, T Rizzi, R Newman, S Antonelli, P Mango, S Di Girolamo, P Esposito, F Grieco, G Summa, D Restieri, R Masiello, G Romano, F Pappalardo, G Pavese, G Mona, L Amodeo, A Pisani, G AF Taylor, J. P. Smith, W. L. Cuomo, V. Larar, A. M. Zhou, D. K. Serio, C. Maestri, T. Rizzi, R. Newman, S. Antonelli, P. Mango, S. Di Girolamo, P. Esposito, F. Grieco, G. Summa, D. Restieri, R. Masiello, G. Romano, F. Pappalardo, G. Pavese, G. Mona, L. Amodeo, A. Pisani, G. TI EAQUATE - An international experiment for hyperspectral atmospheric sounding validation SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID EARLINET PROJECT; RAMAN LIDAR; RETRIEVAL METHODOLOGY; IASI CODE; FRAMEWORK; TEMPERATURE; BACKSCATTER; EXTINCTION; ABSORPTION; RADIANCE AB The international experiment called the European Aqua Thermodynamic Experiment (EAQUATE) was held in September 2004 in Italy and the United Kingdom to validate Aqua satellite Atmospheric Infrared Sounder (AIRS) radiance measurements and derived products with certain ground-based and airborne systems useful for validating hyperspectral satellite sounding observations. A range of flights over land and marine surfaces were conducted to coincide with overpasses of the AIRS instrument on the Earth Observing System Aqua platform. Direct radiance evaluation of AIRS using National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed-Interferometer (NAST-I) and the Scanning High-Resolution Infrared Sounder has shown excellent agreement. Comparisons of level-2 retrievals of temperature and water vapor from AIRS and NAST-I validated against high-quality lidar and dropsonde data show that the 1-K/1-km and 10%/1-km requirements for temperature and water vapor (respectively) are generally being met. The EAQUATE campaign has proven the need for synergistic measurements from a range of observing systems for satellite calibration/validation and has paved the way for future calibration/validation activities in support of the Infrared Atmospheric Sounding Interferometer on the European Meteorological Operational platform and Cross-Track Infrared Sounder on the U.S. NPOESS Prepatory Project platform. C1 [Taylor, J. P.; Newman, S.] Met Off, Exeter EX1 3PB, Devon, England. [Smith, W. L.] Hampton Univ, Hampton, VA 23668 USA. [Smith, W. L.] Univ Wisconsin, Madison, WI USA. [Cuomo, V.; Romano, F.; Pappalardo, G.; Pavese, G.; Mona, L.; Amodeo, A.] CNR, Ist Metodol Anal Ambientale, Tito, Italy. [Larar, A. M.; Zhou, D. K.] NASA, Langley Res Ctr, Hampton, VA 23665 USA. [Serio, C.; Di Girolamo, P.; Esposito, F.; Grieco, G.; Summa, D.; Restieri, R.; Masiello, G.] Univ Basilicata, Dipartimento Ingn & Fis Ambiente, I-85100 Potenza, Italy. [Maestri, T.; Rizzi, R.] Univ Bologna, Dept Phys, Alma Mater Studiorum, I-40126 Bologna, Italy. [Antonelli, P.] Mediterranean Agcy Remote Sensing, Benevento, Italy. [Mango, S.] NPOESS Integrated Program Off, Silver Spring, MD USA. [Pisani, G.] Univ Naples Federico II, Consorzio Nazl Interuniv Sci Fis Mat, Naples, Italy. RP Taylor, JP (reprint author), Met Off, FitzRoy Rd, Exeter EX1 3PB, Devon, England. EM jonathan.p.taylor@metoffice.gov.uk RI Taylor, Jonathan/B-3786-2013; Rizzi, Rolando/L-3556-2013; Grieco, Giuseppe/H-6855-2015; Masiello, Guido/I-6459-2015; OI Grieco, Giuseppe/0000-0002-1255-599X; Masiello, Guido/0000-0002-7986-8296; Romano, Filomena/0000-0002-0544-073X; RIZZI, ROLANDO/0000-0001-7792-7806; Serio, Carmine/0000-0002-5931-7681 NR 25 TC 20 Z9 20 U1 4 U2 19 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2008 VL 89 IS 2 BP 203 EP + DI 10.1175/BAMS-89-2-203 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 281NQ UT WOS:000254504700017 ER PT J AU Stetter, JR Li, J AF Stetter, Joseph R. Li, Jing TI Amperometric gas sensors - A review SO CHEMICAL REVIEWS LA English DT Review ID SOLID-POLYMER ELECTROLYTE; ION-EXCHANGE MEMBRANES; IMPREGNATION-REDUCTION METHOD; CARBON NANOTUBE SENSORS; ELECTROCHEMICAL DETECTION; PATTERN-RECOGNITION; SENSING OXYGEN; EXHAUST-GAS; NOX SENSOR; ARRAY C1 [Stetter, Joseph R.] SRI Int, Menlo Pk, CA 94025 USA. [Li, Jing] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Stetter, JR (reprint author), SRI Int, 333 Ravenswood Ave, Menlo Pk, CA 94025 USA. EM joseph.stetter@sri.com NR 99 TC 129 Z9 130 U1 19 U2 128 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2665 J9 CHEM REV JI Chem. Rev. PD FEB PY 2008 VL 108 IS 2 BP 352 EP 366 DI 10.1021/cr0681039 PG 15 WC Chemistry, Multidisciplinary SC Chemistry GA 262RK UT WOS:000253165500003 PM 18201108 ER PT J AU Hou, XY Huang, R Chen, G Liu, S Zhang, X Yu, B Wang, YY AF Hou Xiao-Yu Huang Ru Chen Gang Liu Sheng Zhang Xing Yu Bin Wang Yang-Yuan TI A novel 10-nm physical gate length double-gate junction field effect transistor SO CHINESE PHYSICS B LA English DT Article DE MOSFET; double-gate MOSFET; depletion operation mode ID FINFET AB A novel double-gate (DG) junction field effect transistor (JFET) with depletion operation mode is proposed in this paper. Compared with the conventional DG MOSFET, the novel DG JFET can achieve excellent performance with square body design, which relaxes the requirement on silicon film thickness of DG devices. Moreover, due to the structural symmetry, both p-type and n-type devices can be realized on exactly the same structure, which greatly simplifies integration. It can reduce the delay by about 60% in comparison with the conventional DG MOSFETs. C1 [Hou Xiao-Yu; Huang Ru; Chen Gang; Liu Sheng; Zhang Xing; Wang Yang-Yuan] Peking Univ, Inst Microelect, Beijing 100871, Peoples R China. [Yu Bin] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Huang, R (reprint author), Peking Univ, Inst Microelect, Beijing 100871, Peoples R China. EM huangr@ime.pku.edu.cn NR 12 TC 1 Z9 1 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1674-1056 J9 CHINESE PHYS B JI Chin. Phys. B PD FEB PY 2008 VL 17 IS 2 BP 685 EP 689 PG 5 WC Physics, Multidisciplinary SC Physics GA 273VT UT WOS:000253960700054 ER PT J AU Bednarcyk, BA Aboudi, J Arnold, SM AF Bednarcyk, Brett A. Aboudi, Jacob Arnold, Steven M. TI The equivalence of the radial return and Mendelson methods for integrating the classical plasticity equations SO COMPUTATIONAL MECHANICS LA English DT Article DE classical plasticity; radial return method; Mendelson method AB The radial return method is a well-known algorithm for integrating the classical plasticity equations. Mendelson presented an alternative method for integrating these equations in terms of the so-called plastic strain-total strain plasticity relations. In the present communication, it is shown that, although the two methods appear to be unrelated, they are actually equivalent. A table is provided demonstrating the step by step correspondence of the radial return and Mendelson algorithms in the case of isotropic hardening. C1 [Bednarcyk, Brett A.] Ohio Aerosp Inst, Cleveland, OH USA. [Aboudi, Jacob] Tel Aviv Univ, Ramat Aviv, Israel. [Arnold, Steven M.] NASA, Glenn Res Ctr, Cleveland, OH USA. RP Bednarcyk, BA (reprint author), Ohio Aerosp Inst, Cleveland, OH USA. EM bednarcyk@oai.org NR 7 TC 4 Z9 4 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0178-7675 J9 COMPUT MECH JI Comput. Mech. PD FEB PY 2008 VL 41 IS 5 BP 733 EP 737 DI 10.1007/s00466-007-0228-0 PG 5 WC Mathematics, Interdisciplinary Applications; Mechanics SC Mathematics; Mechanics GA 255QC UT WOS:000252671500009 ER PT J AU Kincaid, RK Easterling, C Jeske, M AF Kincaid, Rex K. Easterling, Catherine Jeske, Meagan TI Computational experiments with heuristics for two nature reserve site selection problems SO COMPUTERS & OPERATIONS RESEARCH LA English DT Article DE tabu search; heuristics; location problems ID TABU SEARCH; ALGORITHMS; MODELS AB Nature reserve site selection has become critical as the human population grows and environmentalists seek ways to preserve species and their natural habitats. Simple tabu searches are developed and tested for two reserve site selection models - the maximal covering species problem and the maximal expected covering problem. The testbed is an Oregon terrestrial vertebrate data set composed of 426 species and 441 hexagonal sites. In addition, an extension to a linearized version of the maximal expected covering problem is proposed and tested. (C) 2006 Elsevier Ltd. All rights reserved. C1 Coll William & Mary, Dept Math, Williamsburg, VA 23185 USA. NASA, Langley Res Ctr, Lockheed Martin, Hampton, VA 23681 USA. Scitor Corp, Hampton, VA 23669 USA. RP Kincaid, RK (reprint author), Coll William & Mary, Dept Math, Williamsburg, VA 23185 USA. EM rrkinc@math.wm.edu NR 19 TC 5 Z9 6 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0305-0548 J9 COMPUT OPER RES JI Comput. Oper. Res. PD FEB PY 2008 VL 35 IS 2 BP 499 EP 512 DI 10.1016/j.cor.2006.03.013 PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Industrial; Operations Research & Management Science SC Computer Science; Engineering; Operations Research & Management Science GA 223KO UT WOS:000250369200016 ER PT J AU Smith, JM Green, SJ Kelley, CA Prufert-Bebout, L Bebout, BM AF Smith, Jason M. Green, Stefan J. Kelley, Cheryl A. Prufert-Bebout, Leslie Bebout, Brad M. TI Shifts in methanogen community structure and function associated with long-term manipulation of sulfate and salinity in a hypersaline microbial mat SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID COENZYME-M-REDUCTASE; GUERRERO-NEGRO; MICROCOLEUS-CHTHONOPLASTES; SP NOV.; METHANOSARCINA-BARKERI; CYANOBACTERIAL MATS; ACETATE OXIDATION; MARINE-SEDIMENTS; GLYCINE BETAINE; MCRA GENES AB Methanogenesis was characterized in hypersaline microbial mats from Guerrero Negro, Baja California Sur, Mexico both in situ and after long-term manipulation in a greenhouse environment. Substrate addition experiments indicate methanogenesis to occur primarily through the catabolic demethylation of non-competitive substrates, under field conditions. However, evidence for the coexistence of other metabolic guilds of methanogens was obtained during a previous manipulation of sulfate concentrations. To fully characterize methanogenesis in these mats, in the absence of competition for reducing equivalents with sulfate-reducing microorganisms, we maintained microbial mats for longer than 1 year under conditions of lowered sulfate and salinity levels. The goal of this study was to assess whether observed differences in methane production during sulfate and salinity manipulation were accompanied by shifts in the composition of methanogen communities. Culture-independent techniques targeting methyl coenzyme M reductase genes (mcrA) were used to assess the dynamics of methanogen assemblages. Clone libraries from mats sampled in situ or maintained at field-like conditions in the greenhouse were exclusively composed of sequences related to methylotrophic members of the Methanosarcinales. Increases in pore water methane concentrations under conditions of low sulfate correlated with an observed increase in the abundance of putatively hydrogenotrophic mcrA, related to Methanomicrobiales. Geochemical and molecular data provide evidence of a significant shift in the metabolic pathway of methanogenesis from a methylotroph-dominated system in high-sulfate environments to a mixed community of methylotrophic and hydrogenotrophic methanogens under low sulfate conditions. C1 [Smith, Jason M.; Green, Stefan J.; Prufert-Bebout, Leslie; Bebout, Brad M.] NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. [Kelley, Cheryl A.] Univ Missouri, Dept Geol Sci, Columbia, MO USA. RP Bebout, BM (reprint author), NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. EM brad.m.bebout@nasa.gov RI Green, Stefan/C-8980-2011; Kelley, Cheryl/K-9392-2015; OI Green, Stefan/0000-0003-2781-359X NR 52 TC 23 Z9 25 U1 1 U2 18 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD FEB PY 2008 VL 10 IS 2 BP 386 EP 394 DI 10.1111/j.1462-2920.2007.01459.x PG 9 WC Microbiology SC Microbiology GA 250SM UT WOS:000252320800010 PM 18177370 ER PT J AU Kumar, SV Peters-Lidard, CD Eastman, JL Tao, WK AF Kumar, Sujay V. Peters-Lidard, Christa D. Eastman, Joseph L. Tao, Wei-Kuo TI An integrated high-resolution hydrometeorological modeling testbed using LIS and WRF SO ENVIRONMENTAL MODELLING & SOFTWARE LA English DT Article DE land-atmosphere interaction; earth system modeling; hydrologic prediction; mesoscale modeling ID SOIL-MOISTURE; SYSTEM; CONVECTION; FRAMEWORK; PREDICTABILITY; SIMULATION; PREDICTION; ATMOSPHERE; VEGETATION; PROJECT AB Interactions between the atmosphere and the land surface have considerable influences on weather and climate. Coupled land-atmosphere systems that can realistically represent these interactions are thus critical for improving our understanding of the atmosphere-biosphere exchanges of energy, water, and their associated feedbacks. NASA's Land Information System (LIS) is a high-resolution land data assimilation system that integrates advanced land surface models, high-resolution satellite and observational data, data assimilation techniques, and high performance computing tools. LIS has been coupled to the Weather Research and Forecasting (WRF) model, enabling a high-resolution land-atmosphere modeling system. Synthetic simulations using the coupled LIS-WRF system demonstrates the interoperable use of land surface models, high-resolution land surface data and other land surface modeling tools through LIS. Real case study simulations for a June 2002 International H2O Project (IHOP) day is conducted by executing LIS first in an uncoupled manner to generate high-resolution soil moisture and soil temperature initial conditions. During the case study period, the land surface (LIS) and the atmospheric (WRF) models are executed in a coupled manner using the LIS-WRF system. The results from the simulations illustrate the impact of accurate, high-resolution land surface conditions on improving the prediction of clouds and precipitation. Thus, the coupled LIS-WRF system provides a testbed to enable studies in improving our understanding and predictability of regional and global water and energy cycles. (c) 2007 Elsevier Ltd. All rights reserved. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher & Biospher Proc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Kumar, SV (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. EM sujay@hsb.gsfc.nasa.gov RI Kumar, Sujay/B-8142-2015; Peters-Lidard, Christa/E-1429-2012 OI Peters-Lidard, Christa/0000-0003-1255-2876 NR 44 TC 37 Z9 38 U1 0 U2 12 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1364-8152 J9 ENVIRON MODELL SOFTW JI Environ. Modell. Softw. PD FEB PY 2008 VL 23 IS 2 BP 169 EP 181 DI 10.1016/j.envsoft.2007.05.012 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Environmental; Environmental Sciences SC Computer Science; Engineering; Environmental Sciences & Ecology GA 227ZU UT WOS:000250697400004 ER PT J AU Righter, K Chesley, JT Calazza, CM Gibson, EK Ruiz, J AF Righter, K. Chesley, J. T. Calazza, C. M. Gibson, E. K., Jr. Ruiz, J. TI Re and Os concentrations in arc basalts: The roles of volatility and source region fO(2) variations SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Review ID PLATINUM-GROUP ELEMENTS; MEXICAN VOLCANIC BELT; PAPUA-NEW-GUINEA; CALC-ALKALINE MAGMAS; EXPERIMENTAL CONSTRAINTS; OXYGEN FUGACITY; SILICATE MELT; SUBDUCTION ZONE; WESTERN MEXICO; MANTLE WEDGE AB Olivine and spinel compositions, major elements (including ferric and ferrous iron), S, Re and Os contents have been measured for a suite of primitive (most >6 wt% MgO) basalts from the Trans Mexican Volcanic Belt (TMVB), including the western Mexican volcanic belt, the Michoacan-Guanajuato Volcanic Field, Sierra Chichinautzin, Pico de Orizaba region, Palma Sola, San Martin Tuxtlas, and the eastern alkaline province (EAP). Sulfur contents at sulfide saturation were calculated to determine whether the measured S contents are representative of sulfide saturated liquids. Most of the samples have S contents much lower than expected for sulfide saturation. A few have higher contents than calculated perhaps due to the presence of sulfate in the measured total sulfur (i.e., more oxidized samples). Comparison of the TMVB samples along with previously analyzed MORB, OIB, BABB and arc samples reveals a continuum of Re and Os contents that is best explained by variation in oxygen fugacity-and thus sulfide stability-in the source region. High Re and Os magmatic suites are best explained by derivation by melting of oxidized mantle, where sulfide is no longer stable and Re and Os behave incompatibly, whereas low Re and Os magmatic suites are derived from melting of relatively reduced mantle where sulfide is stable, and Re and Os behave compatibly. Intermediate examples abound, and arc magmas span a wide range of Re and Os concentrations due to variation of fO(2) in the source during genesis of arc magmas. Low Re magmatic suites are furthermore potentially affected by volatility which can lower Re by a factor of 3-5. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Righter, K.; Ruiz, J.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. [Chesley, J. T.; Ruiz, J.] Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA. [Calazza, C. M.] Hobart & William Smith Coll, New York, NY USA. RP Righter, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Mailcode KT,2101 NASA Pkwy, Houston, TX 77058 USA. EM kevin.righter-1@nasa.gov NR 133 TC 26 Z9 26 U1 2 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD FEB 1 PY 2008 VL 72 IS 3 BP 926 EP 947 DI 10.1016/j.gca.2007.11.024 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 255ML UT WOS:000252662000015 ER PT J AU Liu, Z Bird, P AF Liu, Zhen Bird, Peter TI Kinematic modelling of neotectonics in the Persia-Tibet-Burma orogen SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE seismicity and tectonics; intra-plate processes; neotectonics; kinematics of crustal and mantle deformation; high strain deformation zones ID CONTEMPORARY CRUSTAL DEFORMATION; POSITIONING SYSTEM MEASUREMENTS; FAULT SLIP RATES; GPS MEASUREMENTS; PLATE MOTIONS; GLOBAL LITHOSPHERE; ACTIVE DEFORMATION; KARAKORAM FAULT; COLLISION ZONE; BLOCK MODEL AB We apply a new kinematic modelling technique (program NeoKinema) to estimate neotectonic flow in the Persia-Tibet-Burma orogen. The models fit geodetic benchmark velocities, geological fault slip rates and stress directions (seismic moment tensor orientations) using a weighted-least-squares method. Models predict long-term velocities, anelastic strain rates and preferred fault slip rates averaged over timescales of 10(4)-10(6) yr. While we find a few regions of low anelastic strain rate, the mean continuum strain rate in the preferred model is 2.2 x 10(-16) s(-1) (0.7 per cent Ma(-1)), so the India-Eurasia collision should not be modelled as an interaction between rigid microplates. For most faults, preferred fault slip rates agree with geological slip rates within their uncertainty bounds; this suggests that deformation imaged by geodesy over tens of years is consistent with deformation over 10(4)-10(6) yr (given appropriate elastic corrections). We also calculate maps of long-term-average seismicity rate based on model fault slip rates and anelastic strain rates in the continuum, using the seismicity parameters of most comparable type of plate boundary. The pattern is generally in agreement with actual m > 5.67 earthquakes in the CMT catalogue (1977-2002), except that the Himalayan front, High Zagros and Altyn Tagh zones have been quieter than predicted. The spatial integral of our forecast over the orogen is 371 m > 5.67 earthquakes/25.75 yr, versus 238 which actually occurred. If this discrepancy has high significance, it means that some step(s) in our forecast method are faulty (such as the assumption of equal coupled seismogenic thickness in all continental convergent boundaries). If it is only an artefact of stochastic time-dependence, then this may have occurred in the orogen, in the external calibration region, or in both. Independent evidence suggests that large earthquakes (with many aftershocks) will occur along the Himalayan front in the future, possibly reducing this discrepancy. C1 [Liu, Zhen; Bird, Peter] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. [Liu, Zhen] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, Z (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. EM zliu@jpl.nasa.gov RI Liu, Zhen/D-8334-2017 NR 68 TC 22 Z9 23 U1 2 U2 10 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD FEB PY 2008 VL 172 IS 2 BP 779 EP 797 DI 10.1111/j.1365-246X.2007.03640.x PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 252FW UT WOS:000252433400023 ER PT J AU Heymsfield, AJ Bansemer, A Matrosov, S Tian, L AF Heymsfield, Andrew J. Bansemer, Aaron Matrosov, Sergey Tian, Lin TI The 94-GHz radar dim band: Relevance to ice cloud properties and CloudSat SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DOPPLER RADAR; PARAMETERIZATIONS; CIRRUS AB Details of the microphysics are shown to be responsible for a region of ice cloud which, when probed from above, has decreasing radar reflectivity (Z(e)) downwards at 94 GHz but increasing Z(e) at 9.7 GHz. This 94-GHz radar dim band is found to be due to the combination of ice particle aggregation and non-Rayleigh scattering effects. Observations and model calculations indicate that it occurs when the particle size distribution (PSD) broadens such that its slope, as derived from fitted PSD, decreases below about 15 cm(-1), or equivalently, to a median volume diameter exceeding 0.25 cm. Dimming occurs at temperatures (T) primarily between -5 and 0 degrees C but can occur at -30 degrees C or below in convectively-generated ice clouds (anvils). The dimming effect may produce an appreciable low bias in the ice water content (IWC) retrieved from Z(e) measured by CloudSat's 94-GHz radar. Methods to estimate the IWC in the dim band are proposed. C1 [Heymsfield, Andrew J.; Bansemer, Aaron] Natl Ctr Atmospher Res, Boulder, CO 80301 USA. [Matrosov, Sergey] NOAA, Environm Technol Lab, Boulder, CO 80303 USA. [Tian, Lin] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heymsfield, AJ (reprint author), Natl Ctr Atmospher Res, 3450 Mitchell Lane, Boulder, CO 80301 USA. EM heyms1@ucar.edu RI Heymsfield, Andrew/E-7340-2011 NR 10 TC 7 Z9 9 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 1 PY 2008 VL 35 IS 3 AR L03802 DI 10.1029/2007GL031361 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 257UM UT WOS:000252824200001 ER PT J AU Tsurutani, BT Echer, E Guarnieri, FL Kozyra, JU AF Tsurutani, Bruce T. Echer, Ezequiel Guarnieri, Fernando L. Kozyra, J. U. TI CAWSES November 7-8, 2004, superstorm: Complex solar and interplanetary features in the post-solar maximum phase SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOMAGNETIC STORMS; MAGNETIC STORMS; WIND; EXPLORER AB The complex interplanetary structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks "pump" up the interplanetary magnetic field from a value of similar to 4 nT to similar to 44 nT. However, the fields after the shocks were northward, and magnetic storms did not result. The three ram pressure increases were associated with major sudden impulses (SI + s) at Earth. A magnetic cloud followed the third forward shock and the southward Bz associated with the latter was responsible for the superstorm. Two reverse waves were detected, one at the edge and one near the center of the magnetic cloud (MC). It is suspected that these "waves" were once reverse shocks which were becoming evanescent when they propagated into the low plasma beta MC. The second reverse wave caused a decrease in the southward component of the IMF and initiated the storm recovery phase. It is determined that flares located at large longitudinal distances from the subsolar point were the most likely causes of the first two shocks without associated magnetic clouds. It is thus unlikely that the shocks were "blast waves" or that magnetic reconnection eroded away the two associated MCs. This interplanetary/solar event is an example of the extremely complex magnetic storms which can occur in the post-solar maximum phase. C1 [Tsurutani, Bruce T.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Echer, Ezequiel] Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP, Brazil. [Guarnieri, Fernando L.] Univ Vale Paraiba, Inst Pesquisas Desenvolvimento, BR-12244000 Sao Jose Dos Campos, Brazil. [Kozyra, J. U.] Univ Michigan, Dept Atmospher Ocean & Space Sci, Space Phys Res Lab, Ann Arbor, MI 48109 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, MS 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bruce.t.tsurutani@jpl.nasa.gov NR 23 TC 33 Z9 33 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 1 PY 2008 VL 35 IS 6 AR L06S05 DI 10.1029/2007GL031473 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 257UQ UT WOS:000252824600001 ER PT J AU Taylor, SG AF Taylor, Sidney G. TI Climate warming causes phenological shift in Pink Salmon, Oncorhynchus gorbuscha, behavior at Auke Creek, Alaska SO GLOBAL CHANGE BIOLOGY LA English DT Article DE climate change; migration timing; Oncorhynchus gorbuscha; pink salmon; water temperature ID MARINE SURVIVAL; VARIABILITY; PACIFIC; KISUTCH; TRENDS; FRY AB Thirty-four years (1972-2005) of water temperature data and extensive biological observations at Auke Creek, Alaska indicate a general warming trend that affected the native pink salmon (Oncorhynchus gorbuscha) population. Serial environmental records at nearby Auke Bay, Alaska over 46 years show trends of increasing air and sea surface temperatures. Trends of increased total precipitation and earlier date of ice out on nearby Auke Lake also occurred, but not at significant rates. Average water temperatures during the incubation of pink salmon in Auke Creek increased at a rate of 0.03 degrees C yr(-1) over the 34-year period. For the 1972-2005 broods, midpoints of fry migrations from Auke Creek ranged between April 2 and May 7, and there was a trend of earlier migration of pink salmon fry at a rate of -0.5 days yr(-1). The migration timing of adult salmon into Auke Creek also showed a trend toward earlier timing. The earlier adult migration combined. with warmer incubation temperatures are related to earlier migration of pink salmon fry. If the observed warming trend continues, Auke Creek may become unsuitable habitat for pink salmon. Given the trend for salmon fry to migrate earlier, a larger portion of the population may become mismatched with optimum environmental conditions during their early marine life history. If salmon adults continue to migrate into the creek earlier when water temperatures are commonly high, it will result in increased prespawning mortality. C1 [Taylor, Sidney G.] Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Dept Commerce, Auke Bay Lab, Juneau, AK 99801 USA. RP Taylor, SG (reprint author), Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Dept Commerce, Auke Bay Lab, 17109 Point Lena Loop Rd, Juneau, AK 99801 USA. EM jerry.taylor@noaa.gov NR 28 TC 43 Z9 43 U1 4 U2 28 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD FEB PY 2008 VL 14 IS 2 BP 229 EP 235 DI 10.1111/j.1365-2486.2007.01494.x PG 7 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 264TN UT WOS:000253313400003 ER PT J AU Schroder, C Klingelhofer, G Morris, RV Rodionov, DS Fleischer, I Blumers, M AF Schroeder, Christian Klingelhoefer, Goestar Morris, Richard V. Rodionov, Daniel S. Fleischer, Iris Blumers, Mathias TI Extraterrestrial Mossbauer spectroscopy: more than 3 years of Mars exploration and developments for future missions SO HYPERFINE INTERACTIONS LA English DT Article; Proceedings Paper CT 29th International Conference on the Applications of the Mossbauer Effect (ICAME) CY OCT 14-19, 2007 CL Indian Inst Technol, Kanpur, INDIA HO Indian Inst Technol DE Mars Exploration Rover; ExoMars; Phobos-Grunt; Jarosite; Iron geochemistry; Exobiology ID MERIDIANI-PLANUM; GUSEV CRATER; SPIRIT ROVER; SPECTROMETER; MINERALOGY; CHEMISTRY; HEMATITE; SOILS; WATER AB After almost 4 years of operating on the surface of Mars, Mossbauer spectroscopy has become a mature technique for robotic planetary exploration. The combination of quantitative information about the distribution of Fe among its oxidation and coordination states, identification of Fe-bearing phases, and relative distribution of Fe among those phases provides valuable contributions to the search for past water activity, the assessment of past environmental conditions, and the suitability for life of the two NASA Mars Exploration Rover landing sites. Experience from the Mars Exploration Rover Mission highlights needs for improvement of the instruments for future missions such as the Russian Phobos-Grunt and the European ExoMars rover. C1 [Schroeder, Christian; Morris, Richard V.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. [Klingelhoefer, Goestar; Rodionov, Daniel S.; Fleischer, Iris; Blumers, Mathias] Johannes Gutenberg Univ Mainz, Inst Anorgan & Analyt Chem, D-55099 Mainz, Germany. [Rodionov, Daniel S.] Space Res Inst IKI, Moscow, Russia. RP Schroder, C (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code KR,2101 NASA Pkwy, Houston, TX 77058 USA. EM christian.schroeder-1@nasa.gov; klingel@mail.uni-mainz.de; richard.v.morris@nasa.gov; rodionov@iki.rssi.ru; fleischi@uni-mainz.de; mblumers@uni-mainz.de RI Schroder, Christian/B-3870-2009 OI Schroder, Christian/0000-0002-7935-6039 NR 26 TC 5 Z9 5 U1 0 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0304-3843 J9 HYPERFINE INTERACT JI Hyperfine Interact. PD FEB PY 2008 VL 182 IS 1-3 BP 149 EP 156 DI 10.1007/s10751-008-9719-4 PG 8 WC Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Physics, Nuclear SC Physics GA 368QO UT WOS:000260637800015 ER PT J AU Buratti, BJ AF Buratti, Bonnie J. TI Damon P. Simonelli (1959-2004) - In memoriam SO ICARUS LA English DT Biographical-Item C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buratti, BJ (reprint author), CALTECH, Jet Prop Lab, MS 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bonnie.buratti@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 303 EP 304 DI 10.1016/j.icarus.2007.11.003 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700001 ER PT J AU Lopes, RMC Buratti, BJ Hendrix, AR AF Lopes, R. M. C. Buratti, B. J. Hendrix, A. R. TI The Saturn system's icy satellites: New results from Cassini SO ICARUS LA English DT Editorial Material ID PHOEBE; ENCELADUS C1 [Lopes, R. M. C.; Buratti, B. J.; Hendrix, A. R.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lopes, RMC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rosaly.m.lopes@jpl.nasa.gov RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 14 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 305 EP 308 DI 10.1016/j.icarus.2007.11.002 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700002 ER PT J AU Buratti, BJ Soderlund, K Bauer, J Mosher, JA Hicks, MD Simonelli, DP Jaumann, R Clark, RN Brown, RH Cruikshank, DP Momary, T AF Buratti, B. J. Soderlund, K. Bauer, J. Mosher, J. A. Hicks, M. D. Simonelli, D. P. Jaumann, R. Clark, R. N. Brown, R. H. Cruikshank, D. P. Momary, T. TI Infrared (0.83-5.1 mu m) photometry of Phoebe from the Cassini Visual Infrared Mapping Spectrometer SO ICARUS LA English DT Article DE Saturn, satellites; photometry; infrared observations; satellites; surfaces ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; SATURNS MOON PHOEBE; MULTIPLE-SCATTERING; VOYAGER PHOTOMETRY; OPTICAL-CONSTANTS; PHASE CURVE; ALBEDO MAP; DARK SIDE; SATELLITES; IAPETUS AB Three weeks prior to the commencement of Cassini's 4 year tour of the saturnian system, the spacecraft executed a close flyby of the outer satellite Phoebe. The infrared channel of the Visual Infrared Mapping Spectrometer (VIMS) obtained images of reflected light over the 0.83-5.1 pm spectral range with an average spectral resolution of 16.5 nm, spatial resolution up to 2 km, and over a range of solar phase angles not observed before. These images have been analyzed to derive fundamental photometric parameters including the phase curve and phase integral, spectral geometric albedo, bolometric Bond albedo, and the single scattering albedo. Physical properties of the surface, including macroscopic roughness and the single particle phase function, have also been characterized. Maps of normal reflectance show the existence of two major albedo regimes in the infrared, with gradations between the two regimes and much terrain with substantially higher albedos. The phase integral of Phoebe is 0.29 +/- 0.03, with no significant wavelength dependence. The bolometric Bond albedo is 0.023 +/- 007. We find that the surface of Phoebe is rough, with a mean slope angle of 33 degrees. The satellite's surface has a substantial forward scattering component, suggesting that its surface is dusty, perhaps from a history of outgassing. The spectrum of Phoebe is best matched by a composition including water ice, amorphous carbon, iron-bearing minerals, carbon dioxide, and Triton tholin. The characteristics of Phoebe suggest that it originated outside the saturnian system, perhaps in the Kuiper Belt, and was captured on its journey inward, as suggested by Johnson and Lunine (2005). (c) 2007 Elsevier Inc. All rights reserved. C1 [Buratti, B. J.; Bauer, J.; Mosher, J. A.; Hicks, M. D.; Momary, T.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Soderlund, K.] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. [Jaumann, R.] DLR, Inst Planet Expl, D-12489 Berlin, Germany. [Clark, R. N.] US Geol Survey, Denver Fed Ctr, Lakewood, CO 80225 USA. [Brown, R. H.] Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. [Brown, R. H.] Univ Arizona, LPL, Tucson, AZ 85721 USA. [Cruikshank, D. P.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Buratti, BJ (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501, Pasadena, CA 91109 USA. EM bonnie.burattii@jpl.nasa.gov NR 53 TC 29 Z9 29 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 309 EP 322 DI 10.1016/j.icarus.2007.09.014 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700003 ER PT J AU Hendrix, AR Hansen, CJ AF Hendrix, Amanda R. Hansen, Candice J. TI Ultraviolet observations of Phoebe from the Cassini UVIS SO ICARUS LA English DT Article DE ultraviolet observations; spectroscopy; Saturn; satellites; ices; UV spectroscopy ID SATURNS MOON PHOEBE; OUTER SOLAR-SYSTEM; OPTICAL-CONSTANTS; REFLECTANCE SPECTRA; WATER ICE; GAS-DRAG; SCATTERING; FROSTS; H2O; SPECTROSCOPY AB Observations of Saturn's distant moon Phoebe were made at far-ultraviolet (FUV) (1100-1900 angstrom) and extreme-ultraviolet (EUV) (600-1100 angstrom) wavelengths by the Cassini Ultraviolet Imaging Spectrograph (UVIS) during the Cassini spacecraft flyby on June 11, 2004. These are the first UV spectra of Phoebe and the first detection of water ice on a Solar System surface using FUV wavelengths. The characteristics of water ice in the FUV are presented, and Hapke models are used to interpret the spectra in terms of composition and grain size; the use of both areal and intimate mixing models is explored. Non-ice species used in these models include carbon, ice tholin, Triton tholin, poly-HCN and kerogen. Satisfactory disk-integrated fits are obtained for intimate mixtures of similar to 10% H2O plus a non-ice species. Spatially resolved regions of higher (similar to 20%) and lower (similar to 5%) H2O ice concentrations are also detected. Phoebe does not display any evidence of volatile activity. Upper limits on atomic oxygen and carbon are 5 x 10(11) and 2 x 10(12) atoms/cm(2), respectively, for solar photon scattering. The UVIS detection of water ice on Phoebe, and the ice amounts detected, are consistent with IR measurements and contribute to the evidence for a Phoebe origin in the outer Solar System rather than in the main asteroid belt. (c) 2007 Elsevier Inc. All rights reserved. C1 [Hendrix, Amanda R.; Hansen, Candice J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hendrix, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM arh@jpl.nasa.gov NR 35 TC 16 Z9 16 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 323 EP 333 DI 10.1016/j.icarus.2007.06.030 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700004 ER PT J AU Cruikshank, DP Wegryn, E Ore, CMD Brown, RH Bibring, JP Buratti, BJ Clark, RN McCord, TB Nicholson, PD Pendleton, YJ Owen, TC Filacchione, G Coradini, A Cerroni, P Capaccioni, F Jaumann, R Nelson, RM Baines, KH Sotin, C Bellucci, G Combes, M Langevin, Y Sicardy, B Matson, DL Formisano, V Drossart, P Mennella, V AF Cruikshank, Dale P. Wegryn, Eric Ore, C. M. Dalle Brown, R. H. Bibring, J. -P. Buratti, B. J. Clark, R. N. McCord, T. B. Nicholson, P. D. Pendleton, Y. J. Owen, T. C. Filacchione, G. Coradini, A. Cerroni, P. Capaccioni, F. Jaumann, R. Nelson, R. M. Baines, K. H. Sotin, C. Bellucci, G. Combes, M. Langevin, Y. Sicardy, B. Matson, D. L. Formisano, V. Drossart, P. Mennella, V. TI Hydrocarbons on Saturn's satellites Iapetus and Phoebe SO ICARUS LA English DT Article DE Iapetus; organic chemistry; satellites; composition; spectroscopy ID POLYCYCLIC AROMATIC-HYDROCARBONS; DIFFUSE INTERSTELLAR-MEDIUM; MAPPING SPECTROMETER VIMS; INFRARED-SPECTRA; DARK SIDE; WATER ICE; SPECTROSCOPY; CONSTRAINTS; MOLECULES; THOLINS AB Material of low geometric albedo (p nu <= 0.1) is found on many objects in the outer Solar System, but its distribution in the saturnian satellite system is of special interest because of its juxtaposition with high-albedo ice. In the absence of clear, diagnostic spectral features, the composition of this low-albedo (or "dark") material is generally inferred to be carbon-rich, but the form(s) of the carbon is unknown. Near-infrared spectra of the low-albedo hemisphere of Saturn's satellite Iapetus were obtained with the Visible-Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft at the fly-by of that satellite of 31 December 2004, yielding a maximum spatial resolution on the satellite's surface of similar to 65 km. The spectral region 3-3.6 mu m reveals a broad absorption band, centered at 3.29 mu m, and concentrated in a region comprising about 15% of the low-albedo surface area. This is identified as the C-H stretching mode vibration in polycyclic aromatic hydrocarbon (PAH) molecules. Two weaker bands attributed to -CH2- stretching modes in aliphatic hydrocarbons are found in association with the aromatic band. The bands most likely arise from aromatic and aliphatic units in complex macromolecular carbonaceous material with a kerogen- or coal-like structure, similar to that in carbonaceous meteorites. VIMS spectra of Phoebe, encountered by Cassini on 11 June 2004, also show the aromatic hydrocarbon band, although somewhat weaker than on Iapetus. The origin of the PAH molecular material on these two satellites is unknown, but PAHs are found in carbonaceous meteorites, cometary dust particles, circumstellar dust, and interstellar dust. (c) 2007 Elsevier Inc. All rights reserved. C1 [Cruikshank, Dale P.; Pendleton, Y. J.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Wegryn, Eric; Ore, C. M. Dalle] SETI Inst, Mountain View, CA 94043 USA. [Brown, R. H.] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. [Brown, R. H.] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Buratti, B. J.; Nelson, R. M.; Baines, K. H.; Matson, D. L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Bibring, J. -P.; Langevin, Y.] Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. [Clark, R. N.] US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA. [McCord, T. B.] Space Sci Inst NW, Winthrop, WA 98862 USA. [Nicholson, P. D.] Cornell Univ, Ithaca, NY 14853 USA. [Owen, T. C.] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. [Filacchione, G.; Coradini, A.; Cerroni, P.; Capaccioni, F.; Formisano, V.] INAF IASF, Ist Astrofis Spaziale & Fis Cosmica, I-00133 Rome, Italy. [Jaumann, R.] DLR, Inst Planetary Explorat, D-12489 Berlin, Germany. [Sotin, C.] Univ Nantes, F-44072 Nantes, France. [Bellucci, G.] INAF IASF, Ist Spazio Interplanterario, I-00133 Rome, Italy. [Combes, M.; Sicardy, B.] Observ Paris, Dept Rech Spatial, F-95129 Meudon, France. [Mennella, V.] INAF OAC, I-80131 Naples, Italy. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, Moffett Field, Moffett Field, CA 94035 USA. EM dale.p.cruikshank@nasa.gov OI Cerroni, Priscilla/0000-0003-0239-2741; Bellucci, Giancarlo/0000-0003-0867-8679; Capaccioni, Fabrizio/0000-0003-1631-4314; Filacchione, Gianrico/0000-0001-9567-0055 NR 38 TC 51 Z9 51 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 334 EP 343 DI 10.1016/j.icarus.2007.04.036 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700005 ER PT J AU Hendrix, AR Hansen, CJ AF Hendrix, Amanda R. Hansen, Candice J. TI The albedo dichotomy of Iapetus measured at UV wavelengths SO ICARUS LA English DT Article DE ices; UV spectroscopy; Iapetus; satellites; composition; Saturn; satellites; ultraviolet observations ID DARK SIDE; IMAGING SCIENCE; ORGANIC-MATTER; LIGHT-CURVE; WATER ICE; PHOEBE; HYPERION; LAPETUS; SPECTROPHOTOMETRY; SATELLITES AB The dramatic hemispheric dichotomy in albedo displayed by Saturn's moon Iapetus has intrigued astronomers for centuries. Here we report on far-ultraviolet observations of Iapetus' bright and dark terrains from Cassini. We compare the reflectance spectra of Iapetus's dark terrain, Hyperion and Phoebe and find that both Phoebe and Hyperion are richer in water ice than Iapetus' dark terrain. Spectra of the lowest latitudes of the dark terrain display the diagnostic water ice absorption feature; water ice amounts increase within the dark material away from the apex (at 90 degrees W longitude, the center of the dark leading hemisphere), consistent with thermal segregation of water ice. The water ice in the darkest, warmest low latitude regions is not expected to be stable and may be a sign of ongoing or recent emplacement of the dark material from an exogenic source. (c) 2007 Elsevier Inc. All rights reserved. C1 [Hendrix, Amanda R.; Hansen, Candice J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hendrix, AR (reprint author), CALTECH, Jet Prop Lab, Mail Stop 230-250, Pasadena, CA 91109 USA. EM arh@jpl.nasa.gov NR 38 TC 13 Z9 13 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 344 EP 351 DI 10.1016/j.icarus.2007.07.025 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700006 ER PT J AU Hicks, MD Buratti, BJ Basilier, EN AF Hicks, Michael D. Buratti, Bonnie J. Basilier, Erik N. TI BVR photometry of Hyperion near the time of the 2005 Cassini encounter SO ICARUS LA English DT Article DE Saturn; satellites; photometry; rotational dynamics ID ROTATION; PHOEBE; SATELLITES; DYNAMICS; LAPETUS; IAPETUS; IMAGES AB Six nights of BVR photometry and three nights of R photometry were collected over a month-long period shortly after the Cassini encounter with Hyperion on September 24 2005. Our observations were designed to help constrain the rotational state of the chaotically rotating satellite. Fourier analysis of our lightcurve data yields three possible periods: 10.2 +/- 0.2, 13.9 +/- 0.2, and 19.7 +/- 0.4 days. Our B-V and V-R colors agree well with previous ground-based and Voyager 2 measurements. (c) 2007 Elsevier Inc. All rights reserved. C1 [Hicks, Michael D.; Buratti, Bonnie J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hicks, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hicksm@scn.jpl.nasa.gov NR 20 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 352 EP 358 DI 10.1016/j.icarus.2007.06.021 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700007 ER PT J AU Clark, RN Curchin, JM Jaumann, R Cruikshank, DP Brown, RH Hoefen, TM Stephan, K Moore, JM Buratti, BJ Baines, KH Nicholson, PD Nelson, RM AF Clark, Roger N. Curchin, John M. Jaumann, Ralf Cruikshank, Dale P. Brown, Robert H. Hoefen, Todd M. Stephan, Katrin Moore, Jeffrey M. Buratti, Bonnie J. Baines, Kevin H. Nicholson, Philip D. Nelson, Robert M. TI Compositional mapping of Saturn's satellite Dione with Cassini VIMS and implications of dark material in the Saturn system SO ICARUS LA English DT Article DE ices; ices, IR spectroscopy; satellites, composition; satellites, surfaces; Saturn, satellites; Saturn, rings; spectroscopy ID IMAGING SCIENCE; IAPETUS DARK; PHOEBE; ENCELADUS; HYPERION; LAPETUS; RHEA; SPECTROSCOPY; SURFACE; TITAN AB Cassim VIMS has obtained spatially resolved imaging spectroscopy data on numerous satellites of Saturn. A very close fly-by of Dione provided key information for solving the riddle of the origin of the dark material in the Saturn system. The Dione VIMS data show a pattern of bombardment of fine, sub-0.5-mu m diameter particles impacting the satellite from the trailing side direction. Multiple lines of evidence point to an external origin for the dark material on Dione, including the global spatial pattern of dark material, local patterns including crater and cliff walls shielding implantation on slopes facing away from the trailing side, exposing clean ice, and slopes facing the trailing direction which show higher abundances of dark material. Multiple spectral features of the dark material match those seen on Phoebe, Iapetus, Hyperion, Epimetheus and the F-ring, implying the material has a common composition throughout the Saturn system. However, the exact composition of the dark material remains a mystery, except that bound water and, tentatively, ammonia are detected, and there is evidence both for and against cyanide compounds. Exact identification of composition requires additional laboratory work. A blue scattering peak with a strong UV-visible absorption is observed in spectra of all satellites which contain dark material, and the cause is Rayleigh scattering, again pointing to a common origin. The Rayleigh scattering effect is confirmed with laboratory experiments using ice and 0.2-mu m diameter carbon grains when the carbon abundance is less than about 2% by weight. Rayleigh scattering in solids is also confirmed in naturally occurring terrestrial rocks, and in previously published reflectance studies. The spatial pattern, Rayleigh scattering effect, and spectral properties argue that the dark material is only a thin coating on Dione's surface, and by extension is only a thin coating on Phoebe, Hyperion, and Iapetus, although the dark material abundance appears higher on Iapetus, and may be locally thick. As previously concluded for Phoebe, the dark material appears to be external to the Saturn system and may be cometary in origin. We also report a possible detection of material around Dione which may indicate Dione is active and contributes material to the E-ring, but this observation must be confirmed. Published by Elsevier Inc. C1 [Clark, Roger N.; Curchin, John M.; Hoefen, Todd M.] US Geol Survey, Denver Fed Ctr, Lakewood, CO 80225 USA. [Jaumann, Ralf; Stephan, Katrin] German Aerosp Ctr DLR, Inst Planetary Res, D-12489 Berlin, Germany. [Cruikshank, Dale P.; Moore, Jeffrey M.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Brown, Robert H.] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. [Brown, Robert H.] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Buratti, Bonnie J.; Baines, Kevin H.; Nelson, Robert M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Nicholson, Philip D.] Cornell Univ, Ithaca, NY 14853 USA. RP Clark, RN (reprint author), US Geol Survey, Denver Fed Ctr, Mail Stop 964,Box 25046, Lakewood, CO 80225 USA. EM rclark@usgs.gov NR 40 TC 67 Z9 67 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 372 EP 386 DI 10.1016/j.icarus.2007.08.035 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700009 ER PT J AU Mitri, G Showman, AP AF Mitri, Giuseppe Showman, Adam P. TI Thermal convection in ice-I shells of Titan and Enceladus SO ICARUS LA English DT Article DE Enceladus; geophysics; ices; interiors; Saturn; satellites; Titan ID STAGNANT LID CONVECTION; INTERNAL STRUCTURE; DEPENDENT VISCOSITY; RADAR MAPPER; SATELLITES; EVOLUTION; VOLCANISM; DYNAMICS; GANYMEDE; FEATURES AB Cassini-Huygens observations have shown that Titan and Enceladus are geologically active icy satellites. Mitri and Showman [Mitri, G., Showman, A.P., 2005. Icarus 177, 447-460] and McKinnon [McKinnon, W.B., 2006. Icarus 183, 435-450] investigated the dynamics of an ice shell overlying a pure liquid-water ocean and showed that transitions from a conductive state to a convective state have major implications for the surface tectonics. We extend this analysis to the case of ice shells overlying ammonia-water oceans. We explore the thermal state of Titan and Enceladus ice-I shells, and also we investigate the consequences of the ice-I shell conductive-convective switch for the geology. We show that thermal convection can occur, under a range of conditions, in the ice-I shells of Titan and Enceladus. Because the Rayleigh number Ra scales with delta(3/)eta(b), where delta is the thickness of the ice shell and eta(b) is the viscosity at the base of the ice-I shell, and because ammonia in the liquid layer (if any) strongly depresses the melting temperature of the water ice, Ra equals its critical value for two ice-l shell thicknesses: for relatively thin ice shell with warm, low-viscosity base (Onset 1) and for thick ice shell with cold, high-viscosity base (Onset 11). At Onset 1, for a range of heat fluxes, two equilibrium states-corresponding to a thin, conductive shell and a thick, convective shell-exist for a given heat flux. Switches between these states can cause large, rapid changes in the ice-shell thickness. For Enceladus, we demonstrate that an Onset I transition can produce tectonic stress of similar to 500 bars and fractures of several tens of km depth. At Onset 11, in contrast, we demonstrate that zero equilibrium states exist for a range of heat fluxes. For a mean heat flux within this range, the satellite experiences oscillations in surface heat flux and satellite volume with periods of similar to 50-800 Myr even when the interior heat production is constant or monotonically declining in time; these oscillations in the thermal state of the ice-I shell would cause repeated episodes of extensional and compressional tectonism. (c) 2007 Elsevier Inc. All rights reserved. C1 [Mitri, Giuseppe] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Showman, Adam P.] Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. [Showman, Adam P.] Univ Arizona, Planetary Lab, Tucson, AZ 85721 USA. RP Mitri, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM giuseppe.mitri@jpl.nasa.gov NR 47 TC 41 Z9 41 U1 1 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 387 EP 396 DI 10.1016/j.icarus.2007.07.016 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700010 ER PT J AU Newman, SF Buratti, BJ Brown, RH Jaumann, R Bauer, J Momary, T AF Newman, Sarah F. Buratti, B. J. Brown, R. H. Jaumann, R. Bauer, J. Momary, T. TI Photometric and spectral analysis of the distribution of crystalline and amorphous ices on Enceladus as seen by Cassini SO ICARUS LA English DT Article DE Enceladus; geological processes; ices; Saturn; satellites ID WATER-ICE; TEMPERATURE-DEPENDENCE; ION IRRADIATION; SOLID WATER; H2O ICE; PLUME; AMORPHIZATION; SPECTROMETER; SATELLITES; ATMOSPHERE AB Photometric and spectral analysis of data from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) has yielded significant results regarding the properties and composition of the surface of Saturn's satellite Enceladus. We have obtained spectral cubes of this satellite, containing both spatial and spectral information, with a wavelength distribution in the infrared far more extensive than from any previous observations and at much higher spatial resolution. Using a composite mosaic of the satellite, we map the distribution of crystalline and amorphous ices on the surface of Enceladus according to a "crystallinity factor" and also the depth of the temperature- and structure-dependent 1.65 micron water-ice band. These maps show the surface of Enceladus to be mostly crystalline, with a higher degree of crystallinity at the "tiger-stripe" cracks and a larger amorphous signature between these stripes. These results suggest recent geological activity at the "tiger stripe" cracks and an intriguing atmospheric environment over the south pole where amorphous ice is produced either through intense radiative bombardment, flash-freezing of cryovolcanic liquid, or rapid condensation of water vapor particles on icy microspherules or on the surface of Enceladus. (c) 2007 Elsevier Inc. All rights reserved. C1 [Newman, Sarah F.; Buratti, B. J.; Bauer, J.; Momary, T.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Brown, R. H.] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. [Jaumann, R.] German Aerosp Ctr DLR, D-12489 Berlin, Germany. RP Newman, SF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sarah.f.newman@jpl.nasa.gov NR 47 TC 20 Z9 20 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 397 EP 406 DI 10.1016/j.icarus.2007.04.019 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700011 ER PT J AU Jaumann, R Stephan, K Hansen, GB Clark, RN Buratti, BJ Brown, RH Baines, KH Newman, SF Bellucci, G Filacchione, G Coradini, A Cruikshank, DP Griffith, CA Hibbitts, CA McCord, TB Nelson, RM Nicholson, PD Sotin, C Wagner, R AF Jaumann, R. Stephan, K. Hansen, G. B. Clark, R. N. Buratti, B. J. Brown, R. H. Baines, K. H. Newman, S. F. Bellucci, G. Filacchione, G. Coradini, A. Cruikshank, D. P. Griffith, C. A. Hibbitts, C. A. McCord, T. B. Nelson, R. M. Nicholson, P. D. Sotin, C. Wagner, R. TI Distribution of icy particles across Enceladus' surface as derived from Cassini-VIMS measurements SO ICARUS LA English DT Article DE Enceladus; Saturn; satellites ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; OUTER SOLAR-SYSTEM; H2O ICE; IMAGING SPECTROSCOPY; SPECTRAL REFLECTANCE; OPTICAL-CONSTANTS; INFRARED-SPECTRA; MU-M; SATELLITES; WATER AB The surface of Enceladus consists almost completely of water ice. As the band depths of water ice absorptions are sensitive to the size of particles, absorptions can be used to map variations of icy particles across the surface. The Visual and Infrared Mapping Spectrometer (VIMS) observed Enceladus with a high spatial resolution during three Cassini flybys in 2005 (orbits EN 003, EN 004 and EN 011). Based on these data we measured the band depths of water ice absorptions at 1.04, 1.25, 1.5, and 2 pm. These band depths were compared to water ice models that represent theoretically calculated reflectance spectra for a range of particle diameters between 2 pin and 1 mm. The agreement between the experimental (VIMS) and model values supports the assumption that pure water ice characterizes the surface of Enceladus and therefore that variations in band depth correspond to variations in water ice particle diameters. Our measurements show that the particle diameter of water ice increases toward younger tectonically altered surface units with the largest particles exposed in relatively "fresh" surface material. The smallest particles were generally found in old densely cratered terrains. The largest particles (similar to 0.2 mm) are concentrated in the so called "tiger stripes" at the south pole. In general, the particle diameters are strongly correlated with geologic features and surface ages, indicating a stratigraphic evolution of the surface that is caused by cryovolcanic resurfacing and impact gardening. (c) 2007 Elsevier Inc. All rights reserved. C1 [Jaumann, R.; Stephan, K.; Wagner, R.] DLR, Inst Planetary Res, D-12489 Berlin, Germany. [Jaumann, R.] Free Univ Berlin, Inst Geosci, Dept Earth Sci, D-1000 Berlin, Germany. [Hansen, G. B.; Hibbitts, C. A.; McCord, T. B.] Bear Fight Ctr, Winthrop, WA 98862 USA. [Clark, R. N.] US Geol Survey, Denver Fed Ctr, Denver, CO 80225 USA. [Buratti, B. J.; Baines, K. H.; Newman, S. F.; Nelson, R. M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Brown, R. H.; Griffith, C. A.] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. [Bellucci, G.; Filacchione, G.; Coradini, A.] CNR, Ist Fis Spazio Interplanetario, Rome, Italy. [Cruikshank, D. P.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Nicholson, P. D.] Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. [Sotin, C.] Univ Nantes, F-44072 Nantes, France. RP Jaumann, R (reprint author), DLR, Inst Planetary Res, D-12489 Berlin, Germany. EM ralf.jaumann@dlr.de RI Hibbitts, Charles/B-7787-2016; OI Hibbitts, Charles/0000-0001-9089-4391; Bellucci, Giancarlo/0000-0003-0867-8679; Filacchione, Gianrico/0000-0001-9567-0055 NR 52 TC 34 Z9 34 U1 0 U2 10 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 407 EP 419 DI 10.1016/j.icarus.2007.09.013 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700012 ER PT J AU Douglas, S Abbey, W Mielke, R Conrad, P Kanik, I AF Douglas, Susanne Abbey, William Mielke, Randall Conrad, Pamela Kanik, Isik TI Textural and mineralogical biosignatures in an unusual microbialite from Death Valley, California SO ICARUS LA English DT Article DE Astrobiology; Mars; surface; mineralogy; geological processes ID CYANOBACTERIAL-S-LAYER; PASTOS-GRANDES; EVAPORITES; WATER; GYPSUM; PRECIPITATION; STROMATOLITES; BACTERIA; MARINE; DEPOSITION AB For in situ astrobiological studies of Mars or other planets, we must employ strategies that will enable us to verify whether our approach and prototype instruments are actually capable of distinguishing life from non-life. This must be done against a background of rigorously conducted scientific characterization of the environment or sample types being considered for measurement by the instruments under development. In this study we show how a combination of mineralogical and textural features can be considered a biosignature in an early Mars analogue environment, Death Valley, California. We propose that it is a combination. of features in context of the geologic matrix which allows determination of biogenicity to be made. Polymineralic microbialites (organosedimentary formations constructed by microorganisms) from a spring pool at Badwater, within Death Valley National Park, are composed of alternating biogenic and abiogenic minerals in a distinct triplet sequence related to wet and dry seasons. A microbial community, occurring as a black biofilm, produced paired layers of two different mineral types: manganese oxyhydroxides and calcite. These biogenic layers are separated from the next pair by a gypsum layer and appear to be laid down in the wet season, with the gypsum (a mineral positively identified on Mars) precipitating in the dry part of the year, abiogenically (i.e., not dependent on microbial metabolic activity for its deposition). In addition, textural features (smaller grain size and less geometric morphology) unique to the biogenic vs the abiogenic layers, were consistently observed so that texture served as a biosignature in this environment. Published by Elsevier Inc. C1 [Douglas, Susanne; Abbey, William; Mielke, Randall; Conrad, Pamela; Kanik, Isik] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Douglas, S (reprint author), CALTECH, Jet Prop Lab, MS 183-301,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM susanne.douglas@jpl.nasa.gov RI Conrad, Pamela/F-1506-2012 OI Conrad, Pamela/0000-0001-8805-7981 NR 63 TC 16 Z9 16 U1 3 U2 13 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2008 VL 193 IS 2 BP 620 EP 636 DI 10.1016/j.icarus.2007.08.019 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 265NQ UT WOS:000253366700028 ER PT J AU Vilnrotter, V Srinivasan, M AF Vilnrotter, Victor Srinivasan, Meera TI Capacity of large array receivers for deep-space communications in the presence of interference SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE array channel capacity; interference cancellation; phased array receivers ID MIMO CAPACITY; CHANNELS; NOISE AB We develop a model for a large array ground receiver system for use in deep space communications, and analyze the resulting array channel capacity. The model includes effects of array geometry, time-dependent spacecraft orbital trajectory, point and extended interference sources, and elevation-dependent noise and atmospheric channel variations. Channel capacity is expressed as a simple quadratic form dependent upon covariance matrices characterizing the source, interference, and additive noise. This formulation facilitates inclusion of array and channel characteristics into the model, as well as comparison of optimal, suboptimal and equivalent single-antenna configurations on achievable throughput. Realistic examples of ground array channel capacity calculations are presented, demonstrating the impact of array geometry, planetary interference sources, and array combining algorithm design upon the achievable data throughput. C1 [Vilnrotter, Victor] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vilnrotter, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM victor.a.vilnrotter@jpl.nasa.gov NR 16 TC 2 Z9 3 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD FEB PY 2008 VL 56 IS 2 BP 194 EP 200 DI 10.1109/TCOMM.2008.060072 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 261OQ UT WOS:000253089800007 ER PT J AU Lin, B Sun, W Min, Q Hu, Y AF Lin, Bing Sun, Wenbo Min, Qiong Hu, Yongxiang TI Numerical studie's of scattering properties of leaves and leaf moisture influences on the scattering at microwave wavelengths SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT Workshop on Remote Sensing and Modeling of Surgace Properties CY JUN 20-22, 2006 CL Paris Observ, Paris, FRANCE HO Paris Observ DE microwave propagation; scattering; vegetation ID ABSORBING BOUNDARY-CONDITION; TIME-DOMAIN SOLUTION; DIELECTRIC SPECTRUM; LIGHT-SCATTERING; FOREST; VEGETATION; PARTICLES; CANOPIES; MODELS; DISKS AB This paper uses a 3-D finite-difference time-domain method to accurately calculate the single-scattering properties of randomly oriented leaves and evaluate the influence of vegetation water content (VWC) on these properties at frequencies of 19.35 and 37.0 GHz. The studied leaves are assumed to be thin elliptical disks with two different sizes and have various VWC values. Although leaf moisture causes considerable absorption in the scattering process, the effective efficiencies of extinction and scattering of leaves essentially linearly increase with VWC, which is critical for forest remote sensing. Calculated asymmetry factors and phase functions also indicate that there is a significant amount of scattered energy at large scattering angles at microwave wavelengths. This paper can improve the modeling of the radiative transfer by vegetation canopies at the higher frequencies of the microwave spectrum, which is important for passive microwave remote sensing. C1 [Lin, Bing; Hu, Yongxiang] NASA, Langley Res Ctr, Sci Directorate, Hampton, VA 23681 USA. [Sun, Wenbo] Hampton Univ, Dept Atmospher & Planetary Sci, Hampton, VA 23666 USA. [Min, Qiong] SUNY Albany, Ctr Atmospher Sci, Albany, NY 12222 USA. RP Lin, B (reprint author), NASA, Langley Res Ctr, Sci Directorate, Hampton, VA 23681 USA. RI Hu, Yongxiang/K-4426-2012 NR 22 TC 3 Z9 3 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2008 VL 46 IS 2 BP 353 EP 360 DI 10.1109/TGRS.2007.912434 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 254GW UT WOS:000252575400008 ER PT J AU Piepmeier, JR Mohammed, PN Knuble, JJ AF Piepmeier, Jeffrey R. Mohammed, Priscilla N. Knuble, Joseph J. TI A double detector for RFI mitigation in microwave radiometers SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT Workshop on Remote Sensing and Modeling of Surgace Properties CY JUN 20-22, 2006 CL Paris Observ, Paris, FRANCE HO Paris Observ DE kurtosis; radio-frequency interference (RFI); radiometer; signal detection ID RADIOFREQUENCY INTERFERENCE; L-BAND; LAND AB A double detector (DD) for radio-frequency interference (RFI) in microwave radiometers is demonstrated in theory and practice. The detector is based on the principle of using kurtosis to detect the presence of non-Gaussian signals and is shown to approximate the kurtosis of input. Theoretical response to continuous wave and pulsed RFI is derived and tested in two experiments. The DD hardware comprises two microwave detectors, two integrator-amplifiers, and a wideband video amplifier. The technique is compatible with existing direct-detection radiometer designs and desirable for applications requiring low technological risk. C1 [Piepmeier, Jeffrey R.; Mohammed, Priscilla N.; Knuble, Joseph J.] NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. [Mohammed, Priscilla N.] Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Piepmeier, JR (reprint author), NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. NR 12 TC 25 Z9 25 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2008 VL 46 IS 2 BP 458 EP 465 DI 10.1109/TGRS.2007.909099 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 254GW UT WOS:000252575400018 ER PT J AU Piepmeier, JR Long, DG Njoku, EG AF Piepmeier, Jeffrey R. Long, David G. Njoku, Eni G. TI Stokes antenna temperatures SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT Workshop on Remote Sensing and Modeling of Surgace Properties CY JUN 20-22, 2006 CL Paris Observ, Paris, FRANCE HO Paris Observ DE Jones matrix; Mueller matrix; polarimetry; polarization; radiometry; Stokes parameters ID POLARIMETRIC MICROWAVE RADIOMETER; FARADAY-ROTATION; SOIL-MOISTURE; POLARIZATION; SURFACES AB The growing importance of polarimetric radiometers has led to the need for a detailed theory for Stokes antenna temperatures. In this paper, we provide a full Stokes vector formulation of an antenna temperature that accounts for the entire antenna pattern, which includes polarization mixing in the main-beam and sidelobe effects. To derive the Stokes antenna temperatures, we follow the conventional methods in the Earth remote sensing literature while relying on a coherency algebra approach from radio astronomy. Connections and parallels to the conventional approaches are noted along the way. We also introduce generalizations of beam efficiency and cross polarization for use with polarimetric radiometers. These provide important metrics in the design of future systems. C1 [Piepmeier, Jeffrey R.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Long, David G.] Brigham Young Univ, Dept Elect & Comp Engn, Provo, UT 84602 USA. [Njoku, Eni G.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Piepmeier, JR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM jeff.piepmeier@nasa.gov RI Long, David/K-4908-2015 OI Long, David/0000-0002-1852-3972 NR 38 TC 5 Z9 5 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2008 VL 46 IS 2 BP 516 EP 527 DI 10.1109/TGRS.2007.909597 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 254GW UT WOS:000252575400023 ER PT J AU Edmonds, LD Irom, F AF Edmonds, Larry D. Irom, Farokh TI Extension of a proton SEU cross section model to include 14 MeV neutrons SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE G-type cross section; invariant integral; neutron SEU; proton SEU; upper bound SEU model; U-type cross section ID SINGLE-EVENT UPSET; COMMERCIAL SRAMS; GENERATION AB A model for estimating proton SEU cross sections from heavy-ion test data has been extended to include 14 MeV neutrons. Accuracy is less consistent for neutrons, but predictions can still be used for upper bounds. C1 [Edmonds, Larry D.; Irom, Farokh] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Edmonds, LD (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM larry.d.ed-monds@jpl.nasa.gov; farokh.irom@jpl.nasa.gov NR 23 TC 4 Z9 4 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 2008 VL 55 IS 1 BP 649 EP 655 DI 10.1109/TNS.2007.911321 PN 3 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 263NX UT WOS:000253224900012 ER PT J AU Hall, TM Jewson, S AF Hall, Timothy M. Jewson, Stephen TI Comparison of local and basinwide methods for risk assessment of tropical cyclone landfall SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID HURRICANE RISK AB Two statistical methods for predicting the number of tropical cyclones (TCs) making landfall on sections of the North American coastline are compared. The first method-the "local model"-is derived exclusively from historical landfalls on the particular coastline section. The second method-the "track model"-involves statistical modeling of TC tracks from genesis to lysis, and is based on historical observations of such tracks. Identical scoring schemes are used for each model, derived from the out-of-sample likelihood of a Bayesian analysis of the Poisson landfall number distribution. The track model makes better landfall rate predictions on most coastal regions, when coastline sections at a scale of several hundred kilometers or smaller are considered. The reduction in sampling error due to the use of the much larger dataset more than offsets any bias in the track model. When larger coast sections are considered, there are more historical landfalls, and the local model scores better. This is the first clear justification for the use of track models for the assessment of TC landfall risk on regional and smaller scales. C1 [Hall, Timothy M.] NASA, Goddard Inst Space Studies, New York, NY 10025 USA. [Jewson, Stephen] Risk Management Solut, London, England. RP Hall, TM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM thall@giss.nasa.gov NR 13 TC 14 Z9 14 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD FEB PY 2008 VL 47 IS 2 BP 361 EP 367 DI 10.1175/2007JAMC1720.1 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 282RQ UT WOS:000254585300001 ER PT J AU Kondragunta, S Lee, P Mcqueen, J Kittaka, C Prados, AI Ciren, P Laszlo, I Pierce, RB Hoff, R Szykman, JJ AF Kondragunta, S. Lee, P. Mcqueen, J. Kittaka, C. Prados, A. I. Ciren, P. Laszlo, I. Pierce, R. B. Hoff, R. Szykman, J. J. TI Air quality forecast verification using satellite data SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID AEROSOL OPTICAL-THICKNESS; PARTICULATE MATTER; MODEL DESCRIPTION; RETRIEVALS; DEPTH; OCEAN; VALIDATION; COMPONENT; PRODUCT; SIGNAL AB NOAA's operational geostationary satellite retrievals of aerosol optical depths (AODs) were used to verify National Weather Service developmental (research mode) particulate matter (PM2.5) predictions tested during the summer 2004 International Consortium for Atmospheric Research on Transport and Transformation/New England Air Quality Study (ICARTT/NEAQS) field campaign. The forecast period included long-range transport of smoke from fires burning in Canada and Alaska and a regional-scale sulfate event over the Gulf of Mexico and the eastern United States. Over the 30-day time period for which daytime hourly forecasts were compared with observations, the categorical (exceedance defined as AOD > 0.55) forecast accuracy was between 0% and 20%. Hourly normalized mean bias (forecasts - observations) ranged between -50% and +50% with forecasts being positively biased when observed AODs were small and negatively biased when observed AODs were high. Normalized mean errors are between 50% and 100% with the errors on the lower end during the 18-22 July 2004 time period when a regional-scale sulfate event occurred. Spatially, the errors are small over the regions where sulfate plumes were present. The correlation coefficient also showed similar features (spatially and temporally) with a peak value of similar to 0.6 during the 18-22 July 2004 time period. The dominance of long-range transport of smoke into the United States during the summer of 2004, neglected in the model predictions, skewed the model forecast performance. Enhanced accuracy and reduced normalized mean errors during the time period when a sulfate event prevailed show that the forecast system has skill in predicting PM2.5 associated with urban/industrial pollution events. C1 [Kondragunta, S.; Laszlo, I.; Pierce, R. B.] NESDIS, NOAA, Ctr Satellite Applicat & Res, Camp Springs, MD 20746 USA. [Lee, P.] Sci Applicat Int Corp, Camp Springs, MD USA. [Mcqueen, J.] NWS, NOAA, Natl Ctr Environm Predict, Camp Springs, MD USA. [Kittaka, C.] Sci Applicat Int Corp, Hampton, VA USA. [Prados, A. I.] Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. [Ciren, P.] QSS Inc, Camp Springs, MD USA. [Kittaka, C.] NASA, Langley Res Ctr, Norfolk, VA USA. [Szykman, J. J.] US EPA, Off Res & Dev, Res Triangle Pk, NC 27711 USA. RP Kondragunta, S (reprint author), NESDIS, NOAA, Ctr Satellite Applicat & Res, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM shobha.kondragunta@noaa.gov RI Laszlo, Istvan/F-5603-2010; Kondragunta, Shobha/F-5601-2010; Ciren, Pubu/E-6542-2011; Pierce, Robert Bradley/F-5609-2010; Lee, Pius/D-5201-2016 OI Laszlo, Istvan/0000-0002-5747-9708; Kondragunta, Shobha/0000-0001-8593-8046; Pierce, Robert Bradley/0000-0002-2767-1643; NR 35 TC 19 Z9 20 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 EI 1558-8432 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD FEB PY 2008 VL 47 IS 2 BP 425 EP 442 DI 10.1175/2007JAMC1392.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 282RQ UT WOS:000254585300006 ER PT J AU Shige, S Takayabu, YN Tao, WK AF Shige, Shoichi Takayabu, Yukari N. Tao, Wei-Kuo TI Spectral retrieval of latent heating profiles from TRMM PR data. Part III: Estimating apparent moisture sink profiles over tropical oceans SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID MEASURING MISSION TRMM; CLOUD-RESOLVING MODEL; ATMOSPHERE RESPONSE EXPERIMENT; MESOSCALE CONVECTIVE SYSTEM; SCALE WAVE DISTURBANCES; COPT 81 EXPERIMENT; PACIFIC WARM POOL; SOUTH CHINA SEA; SQUALL LINE; TOGA COARE AB The spectral latent heating (SLH) algorithm was developed to estimate apparent heat source (Q(1)) profiles for the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) in Parts I and II of this study. In this paper, the SLH algorithm is used to estimate apparent moisture sink (Q(2)) profiles. The procedure of Q(2) retrieval is the same as that of heating retrieval except for using the Q(2) profile lookup tables derived from numerical simulations of tropical cloud systems from the Tropical Ocean and Global Atmosphere (TOGA) Coupled Ocean-Atmosphere Response Experiment (COARE) utilizing a cloud-resolving model (CRM). The Q(2) profiles were reconstructed from CRM-simulated parameters with the COARE table and then compared with CRM-simulated "true" Q(2) profiles, which were computed directly from the water vapor equation in the model. The consistency check indicates that discrepancies between the SLH-reconstructed and CRM-simulated profiles for Q(2), especially at low levels, are larger than those for Q(1) and are attributable to moistening for the nonprecipitating region that SLH cannot reconstruct. Nevertheless, the SLH-reconstructed total Q(2) profiles are in good agreement with the CRM-simulated ones. The SLH algorithm was applied to PR data, and the results were compared with Q(2) profiles derived from the budget study. Although discrepancies between the SLH-retrieved and sounding-based profiles for Q(2) for the South China Sea Monsoon Experiment (SCSMEX) are larger than those for beating, key features of the vertical profiles agree well. The SLH algorithm can also estimate differences of Q(2) between the western Pacific Ocean and the Atlantic Ocean, consistent with the results from the budget study. C1 [Shige, Shoichi] Osaka Prefecture Univ, Dept Aerosp Engn, Osaka 5998531, Japan. [Takayabu, Yukari N.] Univ Tokyo, Ctr Climate Syst Res, Chiba, Japan. [Takayabu, Yukari N.] Japan Agcy Marine Earth Sci & Technol, Inst Observat Res Global Change, Kanagawa, Japan. [Tao, Wei-Kuo] NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Shige, S (reprint author), Osaka Prefecture Univ, Dept Aerosp Engn, 1-1 Gakuen Cho, Osaka 5998531, Japan. EM shige@aero.osakafu-u.ac.jp RI PMM, JAXA/K-8537-2016 NR 86 TC 26 Z9 26 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD FEB PY 2008 VL 47 IS 2 BP 620 EP 640 DI 10.1175/2007JAMC1738.1 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 282RQ UT WOS:000254585300018 ER PT J AU Gopalswamy, N Akiyama, S Yashiro, S Michalek, G Lepping, RP AF Gopalswamy, N. Akiyama, S. Yashiro, S. Michalek, G. Lepping, R. P. TI Solar sources and geospace consequences of interplanetary magnetic clouds observed during solar cycle 23 SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Recent Observations and Simulations of the Sun-Earth System (ISROSES) CY SEP 17-22, 2006 CL Varna, BULGARIA DE coronal mass ejections; magnetic clouds; space weather; solar cycle ID CORONAL MASS EJECTIONS; GEOEFFECTIVENESS; WIND; DISTURBANCES; PROMINENCE; PARAMETERS; POLARITY; STORMS; SHOCK AB We present results of a statistical investigation of 99 magnetic clouds (MCs) observed during 1995-2005. The MC- associated coronal mass ejections (CMEs) are faster and wider on the average and originate within +/-30 degrees from the solar disk center. The solar sources of MCs also followed the butterfly diagram. The correlation between the magnetic field strength and speed of MCs was found to be valid over a much wider range of speeds. The number of south-north (SN) MCs was dominant and decreased with solar cycle, while the number of north-south (NS) MCs increased confirming the odd-cycle behavior. Two-thirds of MCs were geoeffective; the Dst index was highly correlated with speed and magnetic field in MCs as well as their product. Many (55%) fully northward (FN) MCs were geoeffective solely due to their sheaths. The non-geoeffective MCs were slower (average speed similar to 382 km/s), had a weaker southward magnetic field (average similar to - 5.2 nT), and occurred mostly during the rise phase of the solar activity cycle. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Gopalswamy, N.; Akiyama, S.; Yashiro, S.; Michalek, G.; Lepping, R. P.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Akiyama, S.; Yashiro, S.; Michalek, G.] Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Gopalswamy, N (reprint author), NASA, Goddard Space Flight Ctr, Code 695-0, Greenbelt, MD 20771 USA. EM gopals@ssedmail.gsfc.nasa.gov RI Gopalswamy, Nat/D-3659-2012 NR 27 TC 54 Z9 55 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2008 VL 70 IS 2-4 BP 245 EP 253 DI 10.1016/j.jastp.2007.08.070 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 276JN UT WOS:000254137200008 ER PT J AU Farrugia, CJ Gratton, FT Jordanova, VK Matsui, H Muhlbachler, S Torbert, RB Ogilvie, KW Singer, HJ AF Farrugia, C. J. Gratton, F. T. Jordanova, V. K. Matsui, H. Muehlbachler, S. Torbert, R. B. Ogilvie, K. W. Singer, H. J. TI Tenuous solar winds: Insights on solar wind-magneto sphere interactions SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Recent Observations and Simulations of the Sun-Earth System (ISROSES) CY SEP 17-22, 2006 CL Varna, BULGARIA DE low density solar wind; dayside erosion; quiet-time ring current constants; magnetosheath waves ID PLASMA INSTRUMENT; POLAR; EQUATORIAL; SPACECRAFT; ELECTRONS; EROSION; RING AB During solar cycle 23 quasi-dropouts of the solar wind (density < 1 cm(-3)) were observed. These tenuous winds allow us to probe properties of the magnetosphere and its coupling to the solar wind which would otherwise be obscured by the effect of high density. We focus on five areas which provided new insights into the response of geospace to solar wind variations: (i) the magnetospheric magnetic configuration; (ii) the polar rain; (iii) dayside flux erosion; (iv) magnetosheath waves; and (v) ring current constants. We find: (i) the geostationary field had dipolar strength and was inclined by <= 5 degrees to the dipolar direction; (ii) the solar wind strahl, and consequently the polar rain, were intensified; (iii) the depression of the geostationary field (Delta B-GS) due to dayside flux erosion could be measured and was related to IMF B-2 by Delta B-GS -2.8 + 2.3 B-z (nT); (iv) right-hand electromagnetic ion cyclotron waves were excited alone in the magnetosheath and were generated directly from the temperature anisotropy of the solar wind; (v) ring and magnetopause currents decreased to asymptotic values of 5 and 3 nT, respectively, which are substantially smaller than quiet-time values obtained from statistics. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Farrugia, C. J.; Matsui, H.; Torbert, R. B.] Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. [Gratton, F. T.] UBA, CONICET, FCEyN, INFIP, Buenos Aires, DF, Argentina. [Jordanova, V. K.] Los Alamos Natl Lab, Los Alamos, NM USA. [Muehlbachler, S.] Max Planck Inst Sonnensyst Forsch, Kathlenburg, Lindau, Germany. [Ogilvie, K. W.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Singer, H. J.] NOAA, Space Environm Ctr, Boulder, CO USA. RP Farrugia, CJ (reprint author), Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. EM charlie.farrugia@unh.edu OI Jordanova, Vania/0000-0003-0475-8743 NR 19 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 EI 1879-1824 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2008 VL 70 IS 2-4 BP 371 EP 376 DI 10.1016/j.jastp.2007.08.032 PG 6 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 276JN UT WOS:000254137200023 ER PT J AU Korotova, GI Sibeck, DG Rosenberg, T Petrov, V Styazhkin, V AF Korotova, G. I. Sibeck, D. G. Rosenberg, T. Petrov, V. Styazhkin, V. TI Interball observations of multiple flux transfer events SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Recent Observations and Simulations of the Sun-Earth System (ISROSES) CY SEP 17-22, 2006 CL Varna, BULGARIA DE magnetic reconnection; magnetopause; solar wind; flux transfer events ID MAGNETOPAUSE AB We present results from a statistical study of multiple flux transfer events (FTEs) observed by the Interball-1 spacecraft during 1995-1999. We identified 21 days on which Interball-1 observed 10 or more FTEs. In a database of 807 FTEs, 319 can be identified as multiple FTEs with recurrence times ranging between 50 s and 20 min. Multiple events occur at both equatorial and high latitudes but are most frequently seen on Interball-1 passes that graze the flanks of the magnetosphere. The peak-to-peak amplitudes of multiple FTE Bn signatures vary from 3 to 20 nT but typically lie in the range from 3 to 9 nT, less than amplitudes typical for the FTE database as a whole. The durations of individual FTEs increase with increasing inter-arrival times during sequences of multiple FTEs. Multiple FTEs show a marked tendency to occur for southward IMF orientations, but no preference for high or low solar wind dynamic pressures or velocity. Since the conditions favoring the occurrence of multiple FTEs are similar to those for FTEs as a whole, we conclude that sequences of multiple FTEs must be the norm during periods of southward IMF orientation. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Korotova, G. I.; Rosenberg, T.] Univ Maryland, IPST, College Pk, MD 20742 USA. [Korotova, G. I.; Petrov, V.; Styazhkin, V.] IZMIRAN, Troitsk 142190, Russia. [Sibeck, D. G.] NASA, GSFC, Greenbelt, MD 20723 USA. RP Korotova, GI (reprint author), Univ Maryland, IPST, College Pk, MD 20742 USA. EM Korotova@excite.com RI Sibeck, David/D-4424-2012 NR 14 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2008 VL 70 IS 2-4 BP 391 EP 398 DI 10.1016/j.jastp.2007.08.055 PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 276JN UT WOS:000254137200026 ER PT J AU Buzuukova, N Vovchenko, V AF Buzuukova, N. Vovchenko, V. TI Modeling of proton nose structures in the inner magnetosphere with a self-consistent electric field model SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT International Symposium on Recent Observations and Simulations of the Sun-Earth System (ISROSES) CY SEP 17-22, 2006 CL Varna, BULGARIA DE inner magnetosphere; shielding; self-consistent electric field; ionosphere-magnetosphere coupling; ring current ID PLASMA SHEET; DRIFT ECHOES; PARTICLES; SIMULATION; SATELLITE; MOTION; STORMS AB We present the results of inner magnetosphere numerical modeling with a self-consistent electric field. We reconstruct proton energy-time spectrograms, including some with proton nose structures. Using different sets of input parameters we investigate the role of the dawn-dusk potential drop and plasma sheet concentration on nose structure formation and dynamics. It is shown that nose structures can form up to L approximate to 3.3 under periods of enhanced potential drop. The penetration of nose structures depends on shielding strength, which in turn is governed by boundary plasma concentration. In a quiet interval after a temporary potential drop increase, multiple nose structures are formed. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Buzuukova, N.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Buzuukova, N.; Vovchenko, V.] Russian Acad Sci, Inst Space Res, Moscow V71, Russia. RP Buzuukova, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM nbuzulukova@gmail.com NR 25 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2008 VL 70 IS 2-4 BP 503 EP 510 DI 10.1016/j.jastp.2007.08.028 PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 276JN UT WOS:000254137200040 ER PT J AU Kwon, O Krishnamoorthy, M Cho, YI Sankovic, JM Banerjee, RK AF Kwon, Ohwon Krishnamoorthy, Mahesh Cho, Young I. Sankovic, John M. Banerjee, Rupak K. TI Effect of blood viscosity on oxygen transport in residual stenosed artery following angioplasty SO JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT ASME Summer Bioengineering Conference CY JUN 21-26, 2006 CL Amelia Isl, FL SP ASME ID HEMOGLOBIN SOLUTION; RHEOLOGY; FLOW; WALL; HEMODYNAMICS; HEMATOCRIT; EFFICACY; SURGERY; VIVO AB The effect of blood viscosity on oxygen transport in a stenosed coronary artery during the postangioplasty scenario is studied. In addition to incorporating varying blood viscosity using different hematocrit (Hct) concentrations, oxygen consumption by the avascular wall and its supply from vasa vasorum, nonlinear oxygen binding capacity of the hemoglobin, and basal to hyperemic flow rate changes are included in the calculation of oxygen transport in both the lumen and the avascular wall. The results of this study show that oxygen transport in the postangioplasty residual stenosed artery is affected by non-Newtonian shear-thinning property, of the blood viscosity having variable Het concentration. As Hct increases front 25% to 65%, the diminished recirculation zone for the increased Hct causes the commencement Of pO(2) decrease to shift radially outward by similar to 20% from the center of the artery for the basal flow, but by similar to 10% for the hyperemic flow at the end of the diverging section. Oxygen concentration increases from a minimum value at the core of the recirculation zone to over 90 mm Hg before the lumen-wall interface at the diverging section for the hyperemic flow, which is attributed to increased shear rate and thinner lumen boundary layer for the hyperemic flow, and below 90 mm Hg for the basal flow. As Hct increases from 25% to 65%, the average Of pO(2,min) beyond the diverging section drops by similar to 25 % for the basal flow, whereas it increases by similar to 15 % for the hyperemic flow. Thus, current results with the moderate stenosed artery indicate that reducing Hct might be favorable in terms of increasing O(2) flux and pO(2,min), in the medial region of the wall for the basal flow, while higher Hct is advantageous for the hyperemic flow beyond the diverging section. The results of this study not only provide significant details of oxygen transport under varying pathophysiologic blood conditions such as unusually high blood viscosity and flow rate, but might also be extended to offer implications for drug therapy related to blood-thinning medication and for blood transfusion and hemorrhage. C1 [Kwon, Ohwon; Krishnamoorthy, Mahesh; Banerjee, Rupak K.] Univ Cincinnati, Dept Mech Engn, Cincinnati, OH 45221 USA. [Cho, Young I.] Drexel Univ, Dept Mech Engn & Mech, Philadelphia, PA 19104 USA. [Sankovic, John M.] NASA, Glenn Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. [Banerjee, Rupak K.] Univ Cincinnati, Dept Biomed Engn, Cincinnati, OH 45221 USA. [Banerjee, Rupak K.] Univ Cincinnati, Dept Mech Ind & Nucl Engn, Cincinnati, OH 45221 USA. RP Banerjee, RK (reprint author), Univ Cincinnati, Dept Mech Engn, Cincinnati, OH 45221 USA. EM rupak.banerjee@uc.edu NR 35 TC 0 Z9 0 U1 1 U2 4 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0148-0731 J9 J BIOMECH ENG-T ASME JI J. Biomech. Eng.-Trans. ASME PD FEB PY 2008 VL 130 IS 1 AR 011003 DI 10.1115/1.2838029 PG 11 WC Biophysics; Engineering, Biomedical SC Biophysics; Engineering GA 293VY UT WOS:000255364700003 ER PT J AU Schubert, SD Suarez, MJ Pegion, PJ Koster, RD Bacmeister, JT AF Schubert, Siegfried D. Suarez, Max J. Pegion, Philip J. Koster, Randal D. Bacmeister, Julio T. TI Potential predictability of long-term drought and pluvial conditions in the US Great Plains SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; SOIL-MOISTURE; ATMOSPHERIC CIRCULATION; NORTH-AMERICA; PRECIPITATION; VARIABILITY; CLIMATE; TIMESCALES; SUMMER; FLOODS AB This study examines the predictability of seasonal mean Great Plains precipitation using an ensemble of century-long atmospheric general circulation model (AGCM) simulations forced with observed sea surface temperatures (SSTs). The results show that the predictability (intraensemble spread) of the precipitation response to SST forcing varies on interannual and longer time scales. In particular, this study finds that pluvial conditions are more predictable (have less intraensemble spread) than drought conditions. This rather unexpected result is examined in the context of the physical mechanisms that impact precipitation in the Great Plains. These mechanisms include El Nino-Southern Oscillation's impact on the planetary waves and hence the Pacific storm track (primarily during the cold season), the role of Atlantic SSTs in forcing changes in the Bermuda high and low-level moisture flux into the continent (primarily during the warm season), and soil moisture feedbacks (primarily during the warm season). It is found that the changes in predictability are primarily driven by changes in the strength of the land-atmosphere coupling, such that under dry conditions a given change in soil moisture produces a larger change in evaporation and hence precipitation than the same change in soil moisture would produce under wet soil conditions. The above changes in predictability are associated with a negatively skewed distribution in the seasonal mean precipitation during the warm season-a result that is not inconsistent with the observations. C1 [Schubert, Siegfried D.; Suarez, Max J.; Pegion, Philip J.; Koster, Randal D.; Bacmeister, Julio T.] NASA, Goddard Space Flight Ctr, Earth Sun Explorat Div, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Schubert, SD (reprint author), NASA, Goddard Space Flight Ctr, Earth Sun Explorat Div, Global Modeling & Assimilat Off, Code 661, Greenbelt, MD 20771 USA. EM siegfried.d.schubert@nasa.gov RI Pegion, Philip/E-5247-2012; Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 35 TC 36 Z9 36 U1 0 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD FEB PY 2008 VL 21 IS 4 BP 802 EP 816 DI 10.1175/2007JCLI1741.1 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 263VQ UT WOS:000253245000013 ER PT J AU Ripoll, JF Wray, AA AF Ripoll, J.-F. Wray, A. A. TI A 3-D multiband closure for radiation and neutron transfer moment models SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE radiative transfer; neutron transfer; moment models; maximum entropy closure; multi-band models; ODF; multi-bin models ID ENTROPY EDDINGTON FACTORS; ABSORPTION-COEFFICIENTS; NUMERICAL SIMULATIONS; OPACITY DISTRIBUTION; TIME INTEGRATION; HEAT-TRANSFER; DIFFUSION; SOLAR; HYDRODYNAMICS; CONVECTION AB We derive a 3D multi-band moment model and its associated closure for radiation and neutron transfer. The new closure is analytical and nonlinear but very simple. Its derivation is based on the maximum entropy closure and assumes a Wien shape for the intensity when used in the Eddington tensor. In the multi-band approach, the opacity is re-arranged (binned) according to the opacity value. The multi-band model propagates identically all photons/neutrons having the same opacity. This has been found to be a good approximation on average since the transport is mostly determined by the opacities and less by the frequencies. This same concept is used to derive the closure. We prove on two complex test atmospheres (the solar atmosphere and an artificial atmosphere) that the closure we have derived has good accuracy. All approximations made in deriving the model have been carefully numerically checked and quantified. Published by Elsevier Inc. C1 [Ripoll, J.-F.] Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. [Wray, A. A.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ripoll, JF (reprint author), Los Alamos Natl Lab, Space & Remote Sensing Sci ISR 2, MS D436,POB 1663, Los Alamos, NM 87545 USA. EM ripoll@lanl.gov; wray@nas.nasa.gov NR 65 TC 6 Z9 6 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB 1 PY 2008 VL 227 IS 4 BP 2212 EP 2237 DI 10.1016/j.jcp.2007.08.028 PG 26 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 268SA UT WOS:000253598500004 ER PT J AU Nemec, M Aftosmis, MJ AF Nemec, Marian Aftosmis, Michael J. TI Adjoint sensitivity computations for an embedded-boundary Cartesian mesh method SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE aerodynamic shape optimization; Cartesian mesh; adjoint ID AERODYNAMIC DESIGN OPTIMIZATION; NAVIER-STOKES EQUATIONS; UNSTRUCTURED MESHES; EULER EQUATIONS AB We present a new approach for the computation of shape sensitivities using the discrete adjoint and flow-sensitivity methods on Cartesian meshes with general polyhedral cells (cut-cells) at the wall boundaries. By directly linearizing geometric constructors of the cut-cells, an efficient and robust computation of shape sensitivities is achieved for problems governed by the Euler equations. The accuracy of the linearization is verified by the use of a model problem with an exact solution. Verification studies show that the convergence rate of gradients is second-order for design variables that do not alter the boundary shape, and is reduced to first-order for shape design problems. The approach is applied to several three-dimensional problems, including inverse design and shape optimization of a re-entry capsule in hypersonic flow. The results show that reliable approximations of the gradient are obtained in all cases. The approach is well-suited for geometry control via computer-aided design, and is especially effective for conceptual design studies with complex geometry where fast turn-around time is required. (c) 2007 Elsevier Inc. All rights reserved. C1 [Nemec, Marian] ELORET Corp, Sunnyvale, CA 94086 USA. [Nemec, Marian; Aftosmis, Michael J.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Nemec, M (reprint author), ELORET Corp, Sunnyvale, CA 94086 USA. EM Marian.Nemec@nasa.gov NR 43 TC 7 Z9 8 U1 1 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB 1 PY 2008 VL 227 IS 4 BP 2724 EP 2742 DI 10.1016/j.jcp.2007.11.018 PG 19 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 268SA UT WOS:000253598500028 ER PT J AU Davis, B Turner, TL Seelecke, S AF Davis, Brian Turner, Travis L. Seelecke, Stefan TI Measurement and prediction of the thermomechanical response of shape memory alloy hybrid composite beams SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article DE shape memory alloys; Nitinol; embedded actuators; hybrid composites; nonlinear thermoelasticity; thermal buckling; thermal post-buckling; random response ID MICROMECHANICAL ANALYSIS; THERMOELASTIC MODEL; ACTUATORS; BEHAVIOR AB An experimental and numerical investigation into the static and dynamic responses of shape memory alloy hybrid composite (SMAHC) beams is performed to provide quantitative validation of a recently commercialized numerical analysis/design tool for SMAHC structures. The SMAHC beam specimens consist of a composite matrix with embedded pre-strained SMA actuators, which act against the mechanical boundaries of the structure when thermally activated to adaptively stiffen the structure. Numerical results are produced from the numerical model as implemented into the commercial finite element code ABAQUS. A rigorous experimental investigation is undertaken to acquire high fidelity measurements including infrared thermography and projection moire interferometry for full-field temperature and displacement measurements, respectively. High fidelity numerical results are also obtained from the numerical model and include measured parameters, such as geometric imperfection and thermal load. Excellent agreement is achieved between the predicted and measured results of the static and dynamic thermomechanical response, thereby providing quantitative validation of the numerical tool. C1 [Davis, Brian; Seelecke, Stefan] N Carolina State Univ, Dept Mech & Aerosp Engn, Raleigh, NC 27695 USA. [Turner, Travis L.] NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. RP Davis, B (reprint author), N Carolina State Univ, Dept Mech & Aerosp Engn, Raleigh, NC 27695 USA. EM badavis4@ncsu.edu OI Davis, Brian/0000-0003-4043-8077 NR 27 TC 6 Z9 6 U1 0 U2 5 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD FEB PY 2008 VL 19 IS 2 BP 129 EP 143 DI 10.1177/1045389X06073172 PG 15 WC Materials Science, Multidisciplinary SC Materials Science GA 260YK UT WOS:000253046100001 ER PT J AU Acker, J Leptoukh, G Shen, S Zhu, T Kempler, S AF Acker, James Leptoukh, Gregory Shen, Suhung Zhu, Tong Kempler, Steven TI Remotely-sensed chlorophyll a observations of the northern Red Sea indicate seasonal variability and influence of coastal reefs SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT Fall Meeting of the American-Geophysical-Union CY DEC 13-17, 2004 CL San Francisco, CA SP Amer Geophys Union DE remote sensing; chlorophyll; algal blooms; Middle East; Red Sea ID NUTRIENT ENRICHMENT; CORAL-REEF; AQABA; GULF; SEDIMENT; WATERS; EILAT AB The biological dynamics of the open northern Red Sea (21.5 degrees-27.5 degrees N, 33.5 degrees-40 degrees E) have not been studied extensively, due in part to both the inaccessibility of this desert region and political considerations. Remotely-sensed chlorophyll a data therefore provide a framework to investigate the primary patterns of biological activity in this oceanic basin. Monthly chlorophyll a data from the 8-year Sea-viewing Wide Field-of-View sensor (SeaWiFS) mission, and data from the Moderate Resolution Imaging Spectroradiometer (MODIS), were analyzed with the Goddard Earth Sciences Data and Information Services Center (GES DISC) online data analysis system "Giovanni". The data indicate that despite the normal low chlorophyll a concentrations (0.1-0.2 mg m(-3)) in these oligotrophic waters, there is a characteristic seasonal bloom in March-April in the northernmost open Red Sea (24 degrees to 27.5 degrees N) concurrent with minimum sea surface temperature. The location of the highest chlorophyll concentrations is consistent with a linear box model [Eshel, G., and Naik, N.H., 1997. Climatological coastal jet collision, intermediate water formation, and the general circulation of the Red Sea. J. Phys. Oceanogr. 27(7), 1233-1257.] of Red Sea circulation. Two years in the data set exhibited a different seasonal cycle consisting of a relatively weak northern spring bloom and elevated chlorophyll concentrations to the south (21.5 degrees to 24 degrees N). The data also indicate that large coral reef complexes may be sources of either nutrients or chlorophyll-rich detritus and sediment, enhancing chlorophyll a concentration in waters adjacent to the reefs. (c) 2007 Elsevier B.V. All rights reserved. C1 [Acker, James; Zhu, Tong] Sci Syst & Applicat Inc, NASA, Goddard Earth Sci Data & Informat Serv Ctr, Greenbelt, MD 20771 USA. [Shen, Suhung] NASA, Goddard Earth Sci Data & Informat Serv Ctr, George Mason Univ, Greenbelt, MD 20771 USA. [Acker, James; Leptoukh, Gregory; Shen, Suhung; Zhu, Tong; Kempler, Steven] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Acker, J (reprint author), Sci Syst & Applicat Inc, NASA, Goddard Earth Sci Data & Informat Serv Ctr, Code 610-2, Greenbelt, MD 20771 USA. EM jim.acker@gsfc.nasa.gov NR 30 TC 41 Z9 42 U1 3 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD FEB PY 2008 VL 69 IS 3-4 BP 191 EP 204 DI 10.1016/j.jmarsys.2005.12.006 PG 14 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 246YR UT WOS:000252044800004 ER PT J AU Gregg, WW AF Gregg, Watson W. TI Assimilation of SeaWiFS ocean chlorophyll data into a three-dimensional global ocean model SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT Fall Meeting of the American-Geophysical-Union CY DEC 13-17, 2004 CL San Francisco, CA SP Amer Geophys Union ID MARINE ECOSYSTEM MODEL; PHYSICAL-BIOLOGICAL MODEL; CONSTRAINT PARAMETER-ESTIMATION; NORTH-ATLANTIC; KALMAN FILTER; COLOR DATA; BIOGEOCHEMICAL MODEL; IN-SITU; BIOCHEMICAL-MODEL; JGOFS STATION AB Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll data were assimilated with an established three-dimensional global ocean model. The assimilation improved estimates of chlorophyll relative to a free-run (no assimilation) model. Compared to SeaWiFS, annual bias of the assimilation model was 5.5%, with an uncertainty of 10.1%. The free-run model had a bias of 21.0% and an uncertainty of 65.3%. In situ data were compared to the assimilation model over a 6-year time period from 1998 through 2003, indicating a bias of 0.1%, and an uncertainty of 33.4% for daily coincident, co-located data. SeaWiFS bias was slightly higher at -1.3% and nearly identical uncertainty at 32.7%. The free-run bias and uncertainty at -1.4% and 61.8%, respectively, indicated how much the assimilation improved model results. Annual primary production estimates for the 19982003 period produced a nearly 50% improvement by the assimilation model over the free-run model as compared to a widely used algorithm using SeaWiFS chlorophyll data. These results suggest the potential of assimilation of satellite ocean chlorophyll data for improving model results. (c) 2007 Elsevier B.V All rights reserved. C1 NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Gregg, WW (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 610-1, Greenbelt, MD 20771 USA. EM watson.gregg@nasa.gov NR 76 TC 76 Z9 81 U1 2 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD FEB PY 2008 VL 69 IS 3-4 BP 205 EP 225 DI 10.1016/j.jmarsys.2006.02.015 PG 21 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 246YR UT WOS:000252044800005 ER PT J AU Molinero, JC Ibanez, F Souissi, S Bosc, E Nival, P AF Molinero, Juan Carlos Ibanez, Frederic Souissi, Sami Bosc, Emmanuel Nival, Paul TI Surface patterns of zooplankton spatial variability detected by high frequency sampling in the NW Mediterranean. Role of density fronts SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT Fall Meeting of the American-Geophysical-Union CY DEC 13-17, 2004 CL San Francisco, CA SP Amer Geophys Union DE Northwestern Mediterranean; Ligurian front; high frequency sampling; spatial structure; copepods; salps; krill larvae ID VILLEFRANCHE-SUR-MER; KRILL MEGANYCTIPHANES-NORVEGICA; COPEPOD CENTROPAGES-TYPICUS; LIGURIAN SEA; VERTICAL DISTRIBUTIONS; GEORGES BANK; TEMPORAL FLUCTUATIONS; CALANUS-HELGOLANDICUS; COMMUNITY STRUCTURE; DIEL MIGRATIONS AB High frequency sampling was performed in daylight hours along a 35 km transect in the Ligurian Sea to investigate the upper layer zooplankton distribution during the spring phytoplankton bloom. The results show detailed spatial structure and biomass of key zooplankton functional groups, copepods, salps and krill larvae, within the different water masses characterizing this region. Although observed values of total copepod biomass distribution were rather constant along the transect, species-specific patterns were observed in the copepod spatial distribution. The larger species Calanus helgolandicus, as well as Centropages typicus, Oithona spp., and Oncaea spp., were associated with the frontal zone. However, Acartia spp. had a scattered distribution, and Clausocalanus/Paracalanus did not have a clear pattern. In addition, krill larvae were concentrated in the frontal area and salps had a scattered pattern. The cross-shore zooplankton distribution appeared strongly influenced by both the Northern Ligurian current governing inshore waters, which acts as a major flushing forcing, and the Ligurian front, which governs offshore waters and may act as retention area for zooplankton. (c) 2007 Elsevier B.V. All rights reserved. C1 [Molinero, Juan Carlos; Souissi, Sami] Univ Sci & Technol Lille, Ecosyst Complex Res Grp, Stn Marine, CNRS UMR ELICO 8013, F-62930 Wimereux, France. [Ibanez, Frederic; Nival, Paul] LOV, Stn Zool, F-06234 Villefranche Sur Mer, France. [Bosc, Emmanuel] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Molinero, JC (reprint author), INRA, Stn Hydrobiol Lacustre, BP 511-75,Av Corzent, F-74203 Thonon Les Bains, France. EM molinero@thonon.inra.fr OI Souissi, Sami/0000-0002-6720-0096 NR 76 TC 22 Z9 22 U1 1 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD FEB PY 2008 VL 69 IS 3-4 BP 271 EP 282 DI 10.1016/j.jmarsys.2005.11.023 PG 12 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 246YR UT WOS:000252044800011 ER PT J AU Varela-Feria, FM Ramirez-Rico, J de Arellano-Lopez, AR Martinez-Fernandez, J Singh, M AF Varela-Feria, Francisco M. Ramirez-Rico, Joaquin de Arellano-Lopez, Antonio R. Martinez-Fernandez, Julian Singh, Mrityunjay TI Reaction-formation mechanisms and microstructure evolution of biomorphic SiC SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SILICON-CARBIDE CERAMICS; SELF-DIFFUSION; LIQUID SILICON; DIFFRACTION PATTERNS; MELT INFILTRATION; SINGLE-CRYSTALS; CARBON PREFORMS; WOOD; SI-30; COMPOSITES AB Biomorphic SiC is fabricated by liquid Si infiltration of a carbon preform obtained from pyrolized wood that can be selected for tailored properties. The microstructure and reaction kinetics of biomorphic SiC have been investigated by means of TEM, SEM, EBSD, and partial infiltration experiments. The microstructure of the material consists of SiC and Si and a small fraction of unreacted C. The SiC follows a bimodal size distribution of grains in the micrometer and the nanometer range with no preferential orientation. The infiltration-reaction constant has been determined as 18 x 10(-3) s(-1). These observations suggest that the main mechanism for SiC formation is solution-precipitation in the first stage of growth. If the pores in the wood are small enough they can be choked by SiC grains that act as a diffusion barrier between Si and C. If that is the case, Si will diffuse through SiC forming SiC grains in the nanometer range. C1 [Varela-Feria, Francisco M.; Ramirez-Rico, Joaquin; de Arellano-Lopez, Antonio R.; Martinez-Fernandez, Julian] Univ Seville, Dept Fis Mat Condensada, ICMSE, E-41080 Seville, Spain. [Singh, Mrityunjay] NASA, Glenn Res Ctr, Ohio Aerosp Inst, Cleveland, OH 44135 USA. RP Ramirez-Rico, J (reprint author), Univ Seville, Dept Fis Mat Condensada, ICMSE, POB 1065, E-41080 Seville, Spain. EM jrr@us.es RI Ramirez-Rico, Joaquin/A-7006-2009; MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; OI Ramirez-Rico, Joaquin/0000-0002-1184-0756; MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; R. de Arellano Lopez, Antonio/0000-0002-7443-0244 NR 44 TC 27 Z9 29 U1 1 U2 12 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2461 EI 1573-4803 J9 J MATER SCI JI J. Mater. Sci. PD FEB PY 2008 VL 43 IS 3 BP 933 EP 941 DI 10.1007/s10853-007-2207-4 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 249TT UT WOS:000252253400019 ER PT J AU Sharpe, WN Beheim, GM Evans, LJ Nemeth, NN Jadaan, OM AF Sharpe, William N. Beheim, Glenn M. Evans, Laura J. Nemeth, Noel N. Jadaan, Osama M. TI Fracture strength of single-crystal silicon carbide microspecimens at 24 degrees C and 1000 degrees C SO JOURNAL OF MICROELECTROMECHANICAL SYSTEMS LA English DT Article DE ceramics; material testing; silicon carbide (SiC); temperature ID POISSONS RATIO; STRESS; MICROSTRUCTURES; MODULUS AB Three shapes of silicon carbide tensile specimens were tested-curved with a low stress-concentration factor and straight with a circular hole or an elliptical hole. The nominal thickness was 125 mu m with a net section that is 100-mu m wide; the overall length of these microspecimens was 3.1 mm. They were fabricated by an improved version of deep reactive ion etching, which produced specimens with smooth sidewalls and cross sections having a slightly trapezoidal shape that was exaggerated inside the holes. The novel test setup used a vertical load train extending into a resistance furnace. The specimens had wedge-shaped ends which fit into ceramic grips. The fixed grip was mounted on a ceramic post, and the movable grip was connected to a load cell and actuator outside the furnace with a ceramic-encased nichrome wire. The same arrangement was used for tests at 24 degrees C and at 1000 degrees C. The strengths of the curved specimens for two batches of material (made with slightly different processes) were 0.66 +/- 0.12 and 0.45 +/- 0.20 GPa, respectively, at 24 degrees C with identical values at 1000 degrees C. The fracture strengths of the circular-hole and elliptical-hole specimens (computed from the stress-concentration factors and measured loads at failure) were approximately 1.2 GPa with slight decreases at the higher temperature. Fractographic examinations showed failures initiating on the surface-primarily at corners. Weibull predictions of fracture strengths for the hole specimens based on the properties of the curved specimens were reasonably effective for the circular holes but not for the elliptical holes. C1 [Sharpe, William N.] Johns Hopkins Univ, Baltimore, MD 21218 USA. [Beheim, Glenn M.; Evans, Laura J.; Nemeth, Noel N.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. [Jadaan, Osama M.] Univ Wisconsin, Platteville, WI 53818 USA. RP Sharpe, WN (reprint author), Johns Hopkins Univ, Baltimore, MD 21218 USA. EM sharpe@jhu.edu; glenn.m.beheim@nasa.gov; laura.j.evans@nasa.gov; noel.n.nerneth@nasa.gov; jadaan@uwplatt.edu NR 25 TC 12 Z9 12 U1 2 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1057-7157 J9 J MICROELECTROMECH S JI J. Microelectromech. Syst. PD FEB PY 2008 VL 17 IS 1 BP 244 EP 254 DI 10.1109/JMEMS.2007.912727 PG 11 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, Applied SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation; Physics GA 264BG UT WOS:000253259600027 ER PT J AU Cabanes, C Lee, T Fu, LL AF Cabanes, Cecile Lee, Tong Fu, Lee-Lueng TI Mechanisms of interannual variations of the meridional overturning circulation of the North Atlantic Ocean SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SEA-SURFACE HEIGHT; HEAT-TRANSPORT; PACIFIC-OCEAN; VARIABILITY; MODEL AB The authors investigate the nature of the interannual variability of the meridional overturning circulation (MOC) of the North Atlantic Ocean using an Estimating the Circulation and Climate of the Ocean (ECCO) assimilation product for the period of 1993-2003. The time series of the first empirical orthogonal function of the MOC is found to be correlated with the North Atlantic Oscillation (NAO) index, while the associated circulation anomalies correspond to cells extending over the full ocean depth. Model sensitivity experiments suggest that the wind is responsible for most of this interannual variability, at least south of 40 degrees N. A dynamical decomposition of the meridional streamfunction allows a further look into the mechanisms. In particular, the contributions associated with 1) the Ekman flow and its depth-independent compensation, 2) the vertical shear flow, and 3) the barotropic gyre flowing over zonally varying topography are examined. Ekman processes are found to dominate the shorter time scales (1.5-3 yr), while for longer time scales (3-10 yr) the MOC variations associated with vertical shear flow are of greater importance. The latter is primarily caused by heaving of the pycnocline in the western subtropics associated with the stronger wind forcing. Finally, how these changes in the MOC affect the meridional heat transport (MHT) is examined. It is found that overall, Ekman processes explain a larger part of interannual variability (3-10 yr) for MHT (57%) than for the MOC (33%). C1 [Cabanes, Cecile; Lee, Tong; Fu, Lee-Lueng] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Cabanes, C (reprint author), IFREMER, Ctr Brest, LPO, BP 70, F-29280 Plouzane, France. EM cecile.cabanes@ifremer.fr NR 27 TC 22 Z9 22 U1 0 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD FEB PY 2008 VL 38 IS 2 BP 467 EP 480 DI 10.1175/2007JPO3726.1 PG 14 WC Oceanography SC Oceanography GA 266RV UT WOS:000253455600011 ER PT J AU Chai, WK Tzou, HS Arnold, SM Lee, HJ AF Chai, W. K. Tzou, H. S. Arnold, S. M. Lee, H. -J. TI Magnetostrictive microactuations and modal sensitivities of thin magnetoelastic shells SO JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID NONLINEAR CONSTITUTIVE RELATIONS; CYLINDRICAL-SHELLS; ACTUATOR PATCHES; VIBRATION; SYSTEMS AB This study is to evaluate distributed microscopic actuation characteristics and control actions of segmented magnetostrictive actuator patches laminated on a flexible cylindrical shell panel. A mathematical model and its modal domain governing equations of the cylindrical shell panel laminated with distributed magnetostrictive actuator patches are presented first, followed by the formulation of distributed magnetostrictive control forces and microcontrol actions including circumferential membrane/bending and longitudinal bending control components. Transverse mode shape functions with simply supported boundary conditions are used in the modal control force expressions and the microcontrol action analyses. Control effectives and spatial characteristics of distributed actuators depend on applied magnetic fields and on geometrical (e.g., spatial segmentation, location, and shape) and material (i.e., various actuator materials) properties. Spatially distributed magnetoelectromechanical actuation characteristics contributed by circumferential membrane/bending and longitudinal bending control actions are investigated. Distributed control forces and microactuations of a magnetostrictive actuator patch at various locations are analyzed, and modal-dependent spatial control effectiveness is evaluated. C1 [Chai, W. K.; Tzou, H. S.] Univ Kentucky, Dept Engn Mech, StrucTron Lab, Lexington, KY 40506 USA. [Arnold, S. M.; Lee, H. -J.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chai, WK (reprint author), Univ Kentucky, Dept Engn Mech, StrucTron Lab, Lexington, KY 40506 USA. EM hstzou@engr.uky.edu NR 20 TC 0 Z9 0 U1 1 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0094-9930 J9 J PRESS VESS-T ASME JI J. Press. Vessel Technol.-Trans. ASME PD FEB PY 2008 VL 130 IS 1 AR 011206 DI 10.1115/1.2826451 PG 5 WC Engineering, Mechanical SC Engineering GA 270TP UT WOS:000253743400007 ER PT J AU Robichaud, DJ Hodges, JT Lisak, D Miller, CE Okumura, M AF Robichaud, David J. Hodges, Joseph T. Lisak, Daniel Miller, Charles E. Okumura, Mitchio TI High-precision pressure shifting measurement technique using frequency-stabilized cavity ring-down spectroscopy SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID REFRACTIVE-INDEX; PARAMETERS; AIR; PROFILES; OXYGEN; BAND AB We describe a high-precision method for measuring pressure shifting of absorption lines. The technique involves the acquisition of high-resolution spectra using a cavity ring-down spectrometer whose length is continuously locked to a frequency-stabilized reference laser over a range of sample pressures. We discuss a relatively large correction arising from the pressure-dependence of dispersion in the cavity modes, and we demonstrate pressure shifting measurements in air for transitions in the 16 02 A-band. Pressure shifts in the range -0.011 to -0.007 cm(-1) atm(-1) are reported. We measured relative positions of line centers to within 70kHz and determined pressure shifting coefficients over a 5 kPa pressure range with relative uncertainties approximately equal to 1.0%, which constitutes a five-fold improvement over previous measurements. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Hodges, Joseph T.; Lisak, Daniel] NIST, Proc Measurements Div, Gaithersburg, MD 20899 USA. [Robichaud, David J.; Okumura, Mitchio] CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. [Lisak, Daniel] Nicholas Copernicus Univ, Inst Phys, PL-87100 Torun, Poland. [Miller, Charles E.] CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Hodges, JT (reprint author), NIST, Proc Measurements Div, Gaithersburg, MD 20899 USA. EM joseph.hodges@nist.gov RI Hodges, Joseph/B-4578-2009; Lisak, Daniel/E-1470-2014; Okumura, Mitchio/I-3326-2013 OI Okumura, Mitchio/0000-0001-6874-1137 NR 19 TC 23 Z9 23 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD FEB PY 2008 VL 109 IS 3 BP 435 EP 444 DI 10.1016/j.jqsrt.2007.06.005 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 243XR UT WOS:000251831100006 ER PT J AU Podobedov, VB Plusquellic, DF Siegrist, KE Fraser, GT Ma, Q Tipping, RH AF Podobedov, V. B. Plusquellic, D. F. Siegrist, K. E. Fraser, G. T. Ma, Q. Tipping, R. H. TI New measurements of the water vapor continuum in the region from 0.3 to 2.7 THz SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE continuum; IR; THz; nitrogen; water vapor; atmosphere ID WAVE FOREIGN CONTINUUM; ATMOSPHERIC TRANSMISSION; ABSORPTION; SPECTROMETER; OPACITY; MODEL; CELL; GHZ AB We present a spectroscopic study of the water vapor continuum absorption in the far-IR region from 10 to 90cm(-1) (0.3-2.7THz). The experimental technique combines a temperature-stabilized multipass absorption cell, a polarizing (Martin-Puplett) interferometric spectrometer, and a liquid-He-cooled bolometer detector. The contributions to the absorbance resulting from the structureless H2O-H2O and H2O-N-2 continua have been measured in the temperature range from 293 to 333 K with spectral resolution of 0.04-0.12 cm(-1). The resonant water vapor spectrum was modeled using the HITRAN04 database and a Van Vleck-Weisskopf lineshape function with a 100cm(-1) far-wing cut-off. Within experimental uncertainty, both the H2O-H2O and H2O-N-2 continua demonstrate nearly quadratic dependencies of absorbance on frequency with, however, some deviation near the 2.5 THz window. The absorption coefficients of 3.83 and 0.185 (dB/km)/(kPaTHZ)(2) were measured for self- and foreign-gas continuum, respectively. The corresponding temperature exponents Were found to be 8.8 and 5.7. The theoretically predicted foreign continuum is presented and a reasonable agreement with experiment is obtained. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Podobedov, V. B.; Plusquellic, D. F.; Siegrist, K. E.; Fraser, G. T.] NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. [Ma, Q.] Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. [Tipping, R. H.] Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. RP Podobedov, VB (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. EM Vyacheslav.Podobedov@nist.gov NR 18 TC 27 Z9 31 U1 2 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD FEB PY 2008 VL 109 IS 3 BP 458 EP 467 DI 10.1016/j.jqsrt.2007.07.005 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 243XR UT WOS:000251831100009 ER PT J AU Halbig, MC Mcguffin-Cawley, JD Eckel, AJ Brewer, DN AF Halbig, Michael C. Mcguffin-Cawley, James D. Eckel, Andrew J. Brewer, David N. TI Oxidation kinetics and stress effects for the oxidation of continuous carbon fibers within a microcracked C/SiC ceramic matrix composite SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID SILICON-CARBIDE; THERMOSTRUCTURAL COMPOSITES; BEHAVIOR; PROTECTION; MECHANISMS; REACTIVITY; RESISTANCE; COATINGS; CREEP; C/C AB Carbon fiber-reinforced silicon carbide (C/SiC) composites have the potential to be utilized in many high-temperature structural applications, particularly in aerospace. However, the susceptibility of the carbon fibers to oxidation has hindered the composite's use in long-term reusable applications. In order to identify the composites limitations, fundamental oxidation studies were conducted to determine the effects of such variables as temperature, environment, and stress. The systematic studies first looked at the oxidation of the plain, uncoated carbon fiber, then when fiber was utilized within a C/SiC composite, and finally when a stress was applied to the C/SiC composite (stressed oxidation). The first study, oxidation of just the carbon fibers, showed that the fiber oxidation kinetics occurs in two primary regimes: chemical reaction control and diffusion control. The second study, oxidation of the C/SiC composite, showed the self-protecting effects from the SiC matrix at elevated temperatures when the composite was not stressed. The final study, stressed oxidation of the C/SiC composite, more closely simulated application conditions in which the material is expected to encounter thermal and mechanical stresses. The applied load and temperature will affect the openings of the as-fabricated cracks, which are an unavoidable characteristic of C/SiC composites. The main objective of the paper was to determine the oxidation kinetic regimes for the oxidation of carbon fibers in a cracked silicon carbide matrix under stressed and unstressed conditions. The studies help to provide insights in to the protective approaches, that could be used to prevent oxidation of the fibers within the composite. C1 [Brewer, David N.] US Army Res Lab, Vehicle Technol Directorate, Cleveland, OH 44135 USA. [Mcguffin-Cawley, James D.] Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. [Eckel, Andrew J.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Halbig, MC (reprint author), US Army Res Lab, Vehicle Technol Directorate, Cleveland, OH 44135 USA. EM Michael.C.Halbig@grc.nasa.gov NR 40 TC 31 Z9 34 U1 3 U2 30 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 2008 VL 91 IS 2 BP 519 EP 526 DI 10.1111/j.1551-2916.2007.02170.x PG 8 WC Materials Science, Ceramics SC Materials Science GA 259HJ UT WOS:000252930100027 ER PT J AU Pan, F Peters-Lidard, CD AF Pan, Feiei Peters-Lidard, Christa D. TI On the relationship between mean and variance of soil moisture fields SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Article DE spatial variability; soil moisture; soil texture; soil particle size distribution; evaporation; drainage field capacity; wilting point ID WATER CONTENT; VARIABILITY; PLANT; MODEL AB The objective of this work was to explain an apparent contradiction in the literature related to the relationship between mean and variance (or standard deviation) of soil moisture fields. Some studies found an increase in soil moisture variance with decreasing mean soil moisture, while others showed a decrease. The evidence of maximum variance in the mid-range of mean soil moisture was also reported in the literature. In this paper, we focus on the effects of spatial variability of soil texture on the relationship between variance and mean of soil moisture during soil dry-down processes. Soil texture influences soil moisture mean and variance through its direct effects on evaporation and drainage, which are two main factors controlling soil drying. A differential equation describing soil moisture dry down is proposed and studied. Our study shows that as mean soil moisture is greater than a threshold, variance increases with decreasing mean soil moisture. If mean soil moisture is less than the threshold, variance decreases with decreasing mean soil moisture. The threshold depends on soil texture and is between the field capacity and the wilting point. The soil moisture dry-down equation is also applied to explain the apparent contradiction with regard to the relationship between mean and variance of soil moisture fields reported in the literature. C1 [Pan, Feiei] Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. [Peters-Lidard, Christa D.] NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Pan, F (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. EM feifei.pan@ce.gatech.edu RI Pan, Feifei/D-3370-2015; Peters-Lidard, Christa/E-1429-2012 OI Pan, Feifei/0000-0003-4373-7566; Peters-Lidard, Christa/0000-0003-1255-2876 NR 28 TC 39 Z9 40 U1 0 U2 5 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD FEB PY 2008 VL 44 IS 1 BP 235 EP 242 DI 10.1111/j.1752-1688.2007.00150.x PG 8 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 258CT UT WOS:000252846700018 ER PT J AU Teixeira, J Reynolds, CA Judd, K AF Teixeira, Joao Reynolds, Carolyn A. Judd, Kevin TI Time step sensitivity of nonlinear atmospheric models: Numerical convergence, truncation error growth, and ensemble design - Reply SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Editorial Material C1 [Teixeira, Joao; Reynolds, Carolyn A.; Judd, Kevin] USN, Res Lab, Monterey, CA USA. [Teixeira, Joao] NATO Undersea Res Ctr, La Spezia, Italy. [Judd, Kevin] Univ Western Australia, Perth, WA 6009, Australia. RP Teixeira, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-237, Pasadena, CA 91109 USA. EM teixeira@jpl.nasa.gov RI Judd, Kevin/E-7690-2010 NR 4 TC 2 Z9 2 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD FEB PY 2008 VL 65 IS 2 BP 683 EP 684 DI 10.1175/2007JAS2523.1 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 266BP UT WOS:000253406600025 ER PT J AU Prabhakara, C Iacovazzi, R Yoo, JM Kim, KM Bell, TL AF Prabhakara, C. Iacovazzi, R., Jr. Yoo, J. -M. Kim, K. -M. Bell, T. L. TI A method to estimate rain rate over tropical oceans with the TRMM microwave imager radiometer SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID ATMOSPHERIC WATER-VAPOR; PRECIPITATION RADAR; PROFILING ALGORITHM AB In this preliminary study, we have developed a method to retrieve rain rate on a scale of 20 km from the brightness temperatures measured by the TRMM microwave imaging radiometer (TMI) over the tropical oceans, using the estimates of rain rate R-PR made by the TRMM Precipitation Radar (PR) as a benchmark. The purpose of this study is to demonstrate with a limited amount of PR and TMI data the feasibility of improving the TRMM operational rain retrieval method V6 over the tropical oceans. This study utilizes the TMI-measured brightness temperatures T-19H, T-37H, and T-85H of horizontally polarized microwave radiances at 19, 37 and 85 GHz, respectively, to deduce a salient non-finear parameter zeta that is highly correlated with R-PR over the oceans. Two additional parameters generated from TMI data, omega and Gamma, add significant amounts of rain information to our retrieval method. The parameter omega is based on T-19V and T-21V, the brightness temperatures measured by TMI for vertically polarized microwave radiances at 19 and 21 GHz respectively. This parameter takes advantage of the independent information contained in T-21V, The parameter F depends on the average horizontal gradient of the TMI-measured T-85V (vertically-polarized 85 GHz radiance) in a 20 km footprint. Initially our TMI rain retrieval algorithm is tuned with the help of R-PR for seven cases of 2 degrees x 3 degrees area over tropical oceans. Then it is applied to 13 other independent tropical ocean cases. For these independent cases, the rain rate R* estimated from our method correlates better with R-PR than the rain rate R-V6 retrieved from the present TMI V6 operational retrieval method. On a 20 km scale, the correlation between R,, and R* is better by about 6% compared to that between R-PR and R-V6 The slope of the regression line between the rain rates R-PR and R-V6 is about 0.5. With respect to R-PR, the rain rate R-V6 retrieved from operational V6 method tends to underestimate high rain rates and overestimate low rain rates. The slope of the regression line between R-PR and the rain rate R* retrieved with our method is about 0.8, another indication of the improvement of R* over R-V6 In addition, the area average rain rate on a scale of 2 degrees x 3 degrees deduced from our method agrees better with that of PR by about 7%. C1 [Prabhakara, C.; Bell, T. L.] NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. [Iacovazzi, R., Jr.] Earth Resources Technol Inc, Jessup, MD USA. [Yoo, J. -M.] Ewha Womans Univ, Seoul, South Korea. [Kim, K. -M.] Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Prabhakara, C (reprint author), NASA, Goddard Space Flight Ctr, Code 613-2, Greenbelt, MD USA. EM RAMICP@MSN.COM RI Iacovazzi Jr, Robert/G-3867-2010; Bell, Thomas/G-5425-2012; Kim, Kyu-Myong/G-5398-2014 NR 10 TC 1 Z9 2 U1 0 U2 0 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD FEB PY 2008 VL 86 IS 1 BP 203 EP 212 DI 10.2151/jmsj.86.203 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 288RO UT WOS:000255003700012 ER PT J AU Ylitalo, GM Myers, M Stewart, BS Yochem, PK Braun, R Kashinsky, L Boyd, D Antonelis, GA Atkinson, S Aguirre, AA Krahn, MM AF Ylitalo, Gina M. Myers, Matthew Stewart, Brent S. Yochem, Pamela K. Braun, Robert Kashinsky, Lizabeth Boyd, Daryle Antonelis, George A. Atkinson, Shannon Aguirre, A. Alonso Krahn, Margaret M. TI Organochlorine contaminants in endangered Hawaiian monk seals from four subpopulations in the Northwestern Hawaiian Islands SO MARINE POLLUTION BULLETIN LA English DT Article DE Hawaiian monk seal; endangered species; organochlorines; breeding colony; PCBs ID NORTH PACIFIC-OCEAN; LIONS ZALOPHUS-CALIFORNIANUS; FRENCH FRIGATE SHOALS; SAN-FRANCISCO BAY; PHOCA-VITULINA; POLYCHLORINATED BIPHENYL; HARBOR SEALS; MIDWAY ATOLL; CALLORHINUS-URSINUS; STABLE-ISOTOPES AB We analyzed blubber and blood samples for organochlorines (OCs) from 158 Hawaiian monk seals (Monachus schauinslandi) at four of their six primary breeding colonies in the Northwestern Hawaiian Islands. Levels of OCs in blubber were lower in adult females compared to juveniles or adult males, evidently owing to the transfer of these lipophilic compounds to pups by pregnant and lactating females. Concentrations of Sigma PCBs and p,p'-DDE in blubber generally increased with age until seals were sexually mature and then continued to increase with age in males after puberty. Average levels of PCBs and PCB toxic equivalents (TEQs) in blubber were significantly higher in adult male and juvenile seals at Midway Atoll than the same age class of seals at the other colonies. Unlike concentrations of OCs in blubber, circulating levels of OCs in blood did not vary consistently among age classes of seals or among breeding colonies. Though the concentrations of OCs measured in Hawaiian monk seals were generally equal to or lower than those reported for other pinniped species in the North Pacific Ocean, they were high enough in a few seals to potentially affect their health. (c) 2007 Published by Elsevier Ltd. C1 [Ylitalo, Gina M.; Boyd, Daryle; Krahn, Margaret M.] US Dept Commerce, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. [Myers, Matthew] Univ Alaska Fairbanks, Fairbanks, AK 99775 USA. [Myers, Matthew; Atkinson, Shannon] Alaska SeaLife Ctr, Seward, AK 99664 USA. [Stewart, Brent S.; Yochem, Pamela K.] Hubbs SeaWorld Res Inst, San Diego, CA 92109 USA. [Braun, Robert; Kashinsky, Lizabeth; Antonelis, George A.] US Dept Commerce, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. [Aguirre, A. Alonso] Wildlife Trust, New York, NY 10001 USA. RP Ylitalo, GM (reprint author), US Dept Commerce, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM Gina.Ylitalo@noaa.gov NR 65 TC 11 Z9 11 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD FEB PY 2008 VL 56 IS 2 BP 231 EP 244 DI 10.1016/j.marpolbul.2007.09.034 PG 14 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 275WC UT WOS:000254101900017 PM 18031765 ER PT J AU Greenhall, CA AF Greenhall, Charles A. TI An improved matrix method for evaluating UTC offset uncertainties in the presence of link noises SO METROLOGIA LA English DT Article AB By applying the Algos timescale algorithm to a worldwide ensemble of clocks, the BIPM calculates the offset of UTC from the UTC realization of each participating laboratory. Given the uncertainties and correlations of the time-transfer links between the laboratories, one can evaluate the resultant uncertainties and correlations of the offsets. This paper gives an improved and simplified method for carrying out these evaluations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Greenhall, CA (reprint author), CALTECH, Jet Prop Lab, MS 298,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM cgreenhall@jpl.nasa.gov NR 6 TC 0 Z9 0 U1 1 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0026-1394 J9 METROLOGIA JI Metrologia PD FEB PY 2008 VL 45 IS 1 BP 27 EP 34 DI 10.1088/0026-1394/45/1/005 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 259PO UT WOS:000252951400006 ER PT J AU Conselice, CJ Bundy, K Vivian, U Eisenhardt, P Lotz, J Newman, J AF Conselice, C. J. Bundy, K. Vivian, U. Eisenhardt, P. Lotz, J. Newman, J. TI The faint and extremely red K-band-selected galaxy population in the DEEP2/Palomar fields SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : evolution; galaxies : formation; galaxies : structure ID NEAR-INFRARED OBSERVATIONS; HIGH-REDSHIFT GALAXIES; STAR-FORMING GALAXIES; ORIGINS DEEP SURVEY; EARLY DATA RELEASE; NUMBER COUNTS; MASSIVE GALAXIES; PHOTOMETRIC REDSHIFTS; LUMINOSITY FUNCTION; IMAGING SURVEY AB We present in this paper an analysis of the faint and red near-infrared (NIR) selected galaxy population found in NIR imaging from the Palomar Observatory Wide-Field Infrared Survey. This survey covers 1.53 deg(2) to 5 sigma detection limits of K-vega = 20.5-21 and J(vega) = 22.5, and overlaps with the DEEP2 spectroscopic redshift survey. We discuss the details of this NIR survey, including our J- and K-band counts. We show that the K-band galaxy population has a redshift distribution that varies with K magnitude, with most K < 17 galaxies at z < 1.5 and a significant fraction (38.3 +/- 0.3 per cent) of K > 19 systems at z > 1.5. We further investigate the stellar masses and morphological properties of K-selected galaxies, particularly extremely red objects (EROs), as defined by ( R - K) > 5.3 and (I - K) > 4. One of our conclusions is that the ERO selection is a good method for picking out galaxies at z > 1.2, and within our magnitude limits, the most massive galaxies at these redshifts. The ERO limit finds 75 per cent of all M-* > 10(11)M(circle dot) galaxies at z similar to 1.5 down to K-vega = 19.7. We further find that the morphological breakdown of K < 19.7 EROs is dominated by early-types ( 57 +/- 3 per cent) and peculiars ( 34 +/- 3 per cent). However, about a fourth of the early-types are distorted ellipticals, and within CAS ( concentration, asymmetry, clumpiness) parameter space these bridge the early-type and peculiar population, suggesting a morphological evolutionary sequence. We also investigate the use of a (I - K) > 4 selection to locate EROs, finding that it selects galaxies at slightly higher average redshifts (< z > = 1.43 +/- 0.32) than the ( R - K) > 5.3 limit with < z > = 1.28 +/- 0.23. Finally, by using the redshift distribution of K < 20 selected galaxies, and the properties of our EROs, we are able to rule out all monolithic collapse models for the formation of massive galaxies. C1 [Conselice, C. J.] Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England. [Bundy, K.] Univ Toronto, Dept Astron, Toronto, ON, Canada. [Vivian, U.] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. [Eisenhardt, P.] CALTECH, Jet Prop Lab, Pasadena, CA USA. [Lotz, J.] Natl Opt Astron Observ, Tucson, AZ USA. [Newman, J.] Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Conselice, CJ (reprint author), Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England. EM conselice@nottingham.ac.uk RI Conselice, Christopher/B-4348-2013; OI Conselice, Christopher/0000-0003-1949-7638 NR 88 TC 47 Z9 48 U1 0 U2 1 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 1 PY 2008 VL 383 IS 4 BP 1366 EP 1384 DI 10.1111/j.1365-2966.2007.12686.x PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 252LB UT WOS:000252446900007 ER PT J AU Teixeira, J Reynolds, CA AF Teixeira, Joao Reynolds, Carolyn A. TI Stochastic nature of physical parameterizations in ensemble prediction: A Stochastic convection approach SO MONTHLY WEATHER REVIEW LA English DT Article ID SHALLOW CUMULUS CONVECTION; CLOUD-RESOLVING MODEL; BOUNDARY-LAYER CLOUDS; LARGE-SCALE MODELS; CLIMATE MODELS; SYSTEM; SCHEME; SIMULATION; ERROR; PARAMETRIZATION AB In this paper it is argued that ensemble prediction systems can be devised in such a way that physical parameterizations of subgrid-scale motions are utilized in a stochastic manner, rather than in a deterministic way as is typically done. This can be achieved within the context of current physical parameterization schemes in weather and climate prediction models. Parameterizations are typically used to predict the evolution of grid-mean quantities because of unresolved subgrid-scale processes. However, parameterizations can also provide estimates of higher moments that could be used to constrain the random determination of the future state of a certain variable. The general equations used to estimate the variance of a generic variable are briefly discussed, and a simplified algorithm for a stochastic moist convection parameterization is proposed as a preliminary attempt. Results from the implementation of this stochastic convection scheme in the Navy Operational Global Atmospheric Prediction System (NOGAPS) ensemble are presented. It is shown that this method is able to generate substantial tropical perturbations that grow and "migrate" to the midlatitudes as forecast time progresses while moving from the small scales where the perturbations are forced to the larger synoptic scales. This stochastic convection method is able to produce substantial ensemble spread in the Tropics when compared with results from ensembles created from initial-condition perturbations. Although smaller, there is still a sizeable impact of the stochastic convection method in terms of ensemble spread in the extratropics. Preliminary simulations with initial-condition and stochastic convection perturbations together in the same ensemble system show a promising increase in ensemble spread and a decrease in the number of outliers in the Tropics. C1 [Teixeira, Joao] Naval Res Lab, UCAR Visiting Scientist Program, Monterey, CA USA. [Teixeira, Joao] NATO Undersea Res Ctr, La Spezia, Italy. RP Teixeira, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-237, Pasadena, CA 91109 USA. EM teixeira@jpl.nasa.gov OI Reynolds, Carolyn/0000-0003-4690-4171 NR 55 TC 45 Z9 47 U1 3 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD FEB PY 2008 VL 136 IS 2 BP 483 EP 496 DI 10.1175/2007MWR1870.1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 274YR UT WOS:000254039200006 ER PT J AU Tong, T Zhao, Y Delzeit, L Kashani, A Meyyappan, M Majumdar, A AF Tong, Tao Zhao, Yang Delzeit, Lance Kashani, Ali Meyyappan, M. Majumdar, Arun TI Height independent compressive modulus of vertically aligned carbon nanotube arrays SO NANO LETTERS LA English DT Article ID MULTILAYERED METAL-CATALYSTS; GROWTH; COMPOSITES; STRENGTH AB The compressive modulus of dense vertically aligned multiwalled carbon nanotube (CNT) arrays synthesized by chemical vapor deposition was investigated using an optically probed precision-loading platform. For CNT arrays with heights ranging from 15 to 500 mu m, the moduli were measured to be about 0.25 MPa and were found to be independent of array height. A continuum mechanics model based on multimode buckling guided by the wavy features of CNT arrays is derived and explains well the measured compressive properties. The measured compressive modulus of the CNT arrays also satisfies the "Dahlquist tack criterion" for pressure sensitive adhesives, which was previously observed for these vertically aligned CNT arrays (Zhao, Y., et al. J. Vac. Sci. Technol., B 2006, 24, 331-335). C1 [Tong, Tao; Majumdar, Arun] Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. [Zhao, Yang; Kashani, Ali] Atlas Sci Inc, San Jose, CA 95120 USA. [Delzeit, Lance; Meyyappan, M.] NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. [Majumdar, Arun] Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Majumdar, A (reprint author), Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. EM majumdar@me.berkeley.edu NR 25 TC 60 Z9 61 U1 5 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD FEB PY 2008 VL 8 IS 2 BP 511 EP 515 DI 10.1021/nl072709a PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 262RR UT WOS:000253166200025 PM 18189439 ER PT J AU Strus, MC Zalamea, L Raman, A Pipes, RB Nguyen, CV Stach, EA AF Strus, M. C. Zalamea, L. Raman, A. Pipes, R. B. Nguyen, C. V. Stach, E. A. TI Peeling force spectroscopy: Exposing the adhesive nanomechanics of one-dimensional nanostructures SO NANO LETTERS LA English DT Article ID CARBON NANOTUBES; MECHANICS; FABRICATION; MICROSCOPE; AFM; NANOCOMPOSITES; CANTILEVERS; CALIBRATION; COMPOSITES; ALIGNMENT AB The physics of adhesion and stiction of one-dimensional nanostructures such as nanotubes, nanowires, and biopolymers on different material substrates is of great interest for the study of biological adhesion and the development of nanoelectronics and nanocomposites. Here, we combine theoretical models and a new mode in the atomic force microscope to investigate quantitatively the physics of nanomechanical peeling of carbon nanotubes and nanocoils on different substrates. We demonstrate that when an initially straight nanotube is peeled from a surface, small perturbations can trigger sudden transitions between different geometric configurations of the nanotube with vastly different interfacial energies. This opens up the possibility of quantitative comparison and control of adhesion between nanotubes or nanowires on different substrates. C1 [Strus, M. C.; Raman, A.] Purdue Univ, Sch Mech Engn, Birck Nanotechnol Ctr, W Lafayette, IN 47907 USA. [Zalamea, L.; Stach, E. A.] Purdue Univ, Sch Mat Sci & Engn, W Lafayette, IN USA. [Pipes, R. B.] Purdue Univ, Sch Aeronaut & Astronaut Chem Engn & Mat Sci & En, W Lafayette, IN USA. [Nguyen, C. V.] Eloret Corp, NASA Ames Res Ctr, Moffett Field, CA USA. RP Raman, A (reprint author), Purdue Univ, Sch Mech Engn, Birck Nanotechnol Ctr, W Lafayette, IN 47907 USA. RI Strus, Mark/A-5225-2009; Stach, Eric/D-8545-2011 OI Stach, Eric/0000-0002-3366-2153 NR 45 TC 48 Z9 48 U1 3 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD FEB PY 2008 VL 8 IS 2 BP 544 EP 550 DI 10.1021/nl0728118 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 262RR UT WOS:000253166200032 PM 18189440 ER PT J AU Shindell, D AF Shindell, Drew TI Climate change: Cool ozone SO NATURE GEOSCIENCE LA English DT News Item ID TEMPERATURE TRENDS C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Shindell, D (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM dshindell@giss.nasa.gov NR 7 TC 4 Z9 4 U1 0 U2 4 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 1752-0894 J9 NAT GEOSCI JI Nat. Geosci. PD FEB PY 2008 VL 1 IS 2 BP 85 EP 86 DI 10.1038/ngeo115 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 309AY UT WOS:000256433300004 ER PT J AU Berthelier, JJ Malingre, M Pfaff, R Seran, E Pottelette, R Jasperse, J Lebreton, JP Parrot, M AF Berthelier, Jean-Jacques Malingre, Michel Pfaff, Robert Seran, Elena Pottelette, Raymond Jasperse, John Lebreton, Jean-Pierre Parrot, Michel TI Lightning-induced plasma turbulence and ion heating in equatorial ionospheric depletions SO NATURE GEOSCIENCE LA English DT Article ID HYBRID SOLITARY STRUCTURES; PROCESSING ONBOARD DEMETER; EXPLOSIVE SPREAD-F; MAGNETIC-FIELD; SCIENTIFIC OBJECTIVES; WAVES; ACCELERATION; SIMULATION; COLLAPSE; BUBBLES AB A wide range of plasma instabilities exist in various regions of the terrestrial ionosphere, leading to the development of plasma turbulence, in particular close to the lower-hybrid frequency - the frequency of a longitudinal oscillation of ions and electrons in a magnetized plasma that must be near perpendicular to the magnetic field. Most observations have been carried out in the auroral regions, where intense lower-hybrid emissions are frequently observed, possibly producing solitary structures(1) and ion heating(2-4). Lower-hybrid turbulence with a smaller intensity has also been observed at mid- and low latitudes above thunderstorms(5,6) and was shown to be triggered by the electromagnetic whistler wave generated by the lightning current. Here we present observations of equatorial plasma waves that demonstrate the existence of lower-hybrid solitary structures and the simultaneous occurrence of ion heating in deep, large-scale equatorial plasma depletions that form at night during disturbed geomagnetic conditions. These phenomena follow the development of lower-hybrid turbulence triggered by lightning-induced whistlers, revealing a new coupling process between the troposphere and the ionosphere. Since the energy source of the equatorial solitary structures is different from that involved in the auroral processes, our findings support the idea that the formation of lower-hybrid solitary structures may be a universal mechanism operating in inhomogeneous, magnetized plasma and possibly leading to ion heating and acceleration. C1 [Berthelier, Jean-Jacques; Malingre, Michel; Seran, Elena; Pottelette, Raymond] CETP IPSL, F-94100 St Maur, France. [Pfaff, Robert] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Jasperse, John] Hanscom AFB, AFRL, Bedford, MA 01731 USA. [Lebreton, Jean-Pierre] European Space Technol Ctr, European Space Agcy, NL-2200 AG Noordwijk, Netherlands. [Parrot, Michel] LPCE, F-45045 Orleans, France. RP Berthelier, JJ (reprint author), CETP IPSL, 4 Ave Neptune, F-94100 St Maur, France. EM jean-jacques.berthelier@cetp.ipsl.fr RI Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 28 TC 15 Z9 15 U1 3 U2 5 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 1752-0894 J9 NAT GEOSCI JI Nat. Geosci. PD FEB PY 2008 VL 1 IS 2 BP 101 EP 105 DI 10.1038/ngeo109 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 309AY UT WOS:000256433300012 ER PT J AU Rignot, E Bamber, JL Van Den Broeke, MR Davis, C Li, YH Van De Berg, WJ Van Meijgaard, E AF Rignot, Eric Bamber, Jonathan L. Van Den Broeke, Michiel R. Davis, Curt Li, Yonghong Van De Berg, Willem Jan Van Meijgaard, Erik TI Recent Antarctic ice mass loss from radar interferometry and regional climate modelling SO NATURE GEOSCIENCE LA English DT Article ID SEA-LEVEL RISE; WEST ANTARCTICA; BALANCE; SHEET; SNOWFALL; GLACIER AB Large uncertainties remain in the current and future contribution to sea level rise from Antarctica. Climate warming may increase snowfall in the continent's interior(1-3), but enhance glacier discharge at the coast where warmer air and ocean temperatures erode the buttressing ice shelves(4-11). Here, we use satellite interferometric synthetic-aperture radar observations from 1992 to 2006 covering 85% of Antarctica's coastline to estimate the total mass flux into the ocean. We compare the mass fluxes from large drainage basin units with interior snow accumulation calculated from a regional atmospheric climate model for 1980 to 2004. In East Antarctica, small glacier losses in Wilkes Land and glacier gains at the mouths of the Filchner and Ross ice shelves combine to a near-zero loss of 4 +/- 61 Gt yr(-1). In West Antarctica, widespread losses along the Bellingshausen and Amundsen seas increased the ice sheet loss by 59% in 10 years to reach 132 +/- 60 Gt yr(-1) in 2006. In the Peninsula, losses increased by 140% to reach 60 +/- 46 Gt yr(-1) in 2006. Losses are concentrated along narrow channels occupied by outlet glaciers and are caused by ongoing and past glacier acceleration. Changes in glacier flow therefore have a significant, if not dominant impact on ice sheet mass balance. C1 [Rignot, Eric] Univ Calif Irvine, Irvine, CA 92697 USA. [Rignot, Eric] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Rignot, Eric] Ctr Estudios Cient, Valdivia, Chile. [Bamber, Jonathan L.] Univ Bristol, Bristol BS8 1SS, Avon, England. [Van Den Broeke, Michiel R.; Van De Berg, Willem Jan] Univ Utrecht, Inst Marine & Atmospher Res IMAU, NL-3584 CC Utrecht, Netherlands. [Davis, Curt; Li, Yonghong] Univ Missouri, Columbia, MO 65211 USA. [Van Meijgaard, Erik] Royal Netherlands Meteorol Inst KNMI, NL-3732 GK De Bilt, Netherlands. RP Rignot, E (reprint author), Univ Calif Irvine, Irvine, CA 92697 USA. EM erignot@uci.edu RI van de Berg, Willem Jan/H-4385-2011; Bamber, Jonathan/C-7608-2011; Van den Broeke, Michiel/F-7867-2011; Rignot, Eric/A-4560-2014; Jullion, Loic/B-3304-2011 OI Bamber, Jonathan/0000-0002-2280-2819; Van den Broeke, Michiel/0000-0003-4662-7565; Rignot, Eric/0000-0002-3366-0481; Jullion, Loic/0000-0001-6269-6750 NR 27 TC 493 Z9 509 U1 19 U2 170 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 1752-0894 J9 NAT GEOSCI JI Nat. Geosci. PD FEB PY 2008 VL 1 IS 2 BP 106 EP 110 DI 10.1038/ngeo102 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 309AY UT WOS:000256433300013 ER PT J AU Gallaway, BJ Cole, JG Nance, JM Hart, RA Graham, GL AF Gallaway, Benny J. Cole, John G. Nance, James M. Hart, Rick A. Graham, Gary L. TI Shrimp loss associated with turtle excluder devices: Are the historical estimates statistically biased? SO NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT LA English DT Editorial Material ID BYCATCH REDUCTION DEVICES; PRAWN TRAWL FISHERY; TEDS AB Estimates of penaeid shrimp losses associated with the use of turtle excluder devices (TEDs) in offshore waters of the southeastern USA are derived from a single study conducted from 1988 to 1990. The estimates were based on paired tows in which the inboard and outboard nets on one side of the vessel were equipped with TEDs while the nets on the other side were not. Comparison of the mean catch rates from the TED and control nets provided an estimate of shrimp loss. However, the net positions were not rotated by trip, the try net (i.e., a small shrimp trawl fished off one side of the vessel in front of the trailing inboard net) was fished in front of the inner standard net 70% of the time, and the data show that catches in the standard net trailing the try net were significantly reduced by operation of the try net. These findings warranted a new analysis excluding data from inner net pairs, as is done in the modem gear testing protocol. The reanalysis suggests that the shrimp loss rates for Georgia TEDs with and without accelerator funnels were 5.5% and 7.5%, respectively, and that the highest level of shrimp loss (15%) was associated with the "Super Shooter" TED with an accelerator funnel. The results of the historical study indicated that the shrimp loss rate associated with the Super Shooter design was only 1% and that the shrimp loss rates associated with the Georgia TED with and without accelerator funnels were 3.6% and 13.6%, respectively. Overall, we conclude that the historical estimates are biased. A reanalysis suggests that the shrimp loss rate associated with TED use in offshore waters of the southeastern USA is on the order of 6%. We also conclude that a new, well-designed National Marine Fisheries Service-approved study is needed. C1 [Gallaway, Benny J.; Cole, John G.] LGL Ecol Res Associates Inc, Bryan, TX 77801 USA. [Nance, James M.; Hart, Rick A.] Natl Marine Fisheries Serv, Galveston Lab, Galveston, TX 77551 USA. [Graham, Gary L.] Texas A&M Sea Grant Program, W Columbia, TX 77465 USA. RP Gallaway, BJ (reprint author), LGL Ecol Res Associates Inc, 1410 Cavitt St, Bryan, TX 77801 USA. EM bgallaway@lgl.com NR 13 TC 4 Z9 4 U1 0 U2 4 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0275-5947 J9 N AM J FISH MANAGE JI North Am. J. Fish Manage. PD FEB PY 2008 VL 28 IS 1 BP 203 EP 211 DI 10.1577/M07-002.1 PG 9 WC Fisheries SC Fisheries GA 274WC UT WOS:000254032500019 ER PT J AU Hullavarad, SS Hullavarad, NV Pugel, DE Dhar, S Venkatesan, T Vispute, RD AF Hullavarad, S. S. Hullavarad, N. V. Pugel, D. E. Dhar, S. Venkatesan, T. Vispute, R. D. TI Structural and chemical analysis of pulsed laser deposited MgxZn1-xO hexagonal (x=0.15,0.28) and cubic (x=0.85) thin films SO OPTICAL MATERIALS LA English DT Article ID ULTRAVIOLET PHOTODETECTORS; COMPOSITION SPREADS; MG(X)ZN1-XO ALLOYS; OPTICAL-PROPERTIES; ZNO; SAPPHIRE; DETECTOR; REALIZATION; DEVICES; GAP AB Hexagonal and cubic MgxZn1-xO thin films corresponding to optical band gaps of 3.52eV, 4eV and 6.42eV for x=0.15, 0.28 and 0.85 compositions were grown by pulsed laser deposition technique. The crystalline quality of the films was investigated by X-ray diffraction-rocking curve measurements and indicated a high degree of crystallinity with narrow FWHM's of 0.21 degrees-0.59 degrees. Rutherford back scattering-channeling spectroscopy provides channeling yields of 7-14% indicating the good crystalline quality of the thin films. X-Ray photoelectron spectroscopy measurements clearly indicated different level of oxidation states of Mg and Zn. (C) 2007 Elsevier B.V. All rights reserved. C1 [Hullavarad, S. S.; Hullavarad, N. V.] Univ Alaska, Off Elect Miniaturizat, Fairbanks, AK 99701 USA. [Pugel, D. E.; Dhar, S.; Venkatesan, T.] Univ Maryland, Ctr Supercond Res, College Pk, MD 20742 USA. [Vispute, R. D.] Blue Wave Semicond, Columbia, MD USA. [Pugel, D. E.] NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 20771 USA. RP Hullavarad, SS (reprint author), Univ Alaska, Off Elect Miniaturizat, Fairbanks, AK 99701 USA. EM fnssh1@uaf.edu RI Venkatesan, Thirumalai/E-1667-2013 NR 44 TC 11 Z9 12 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-3467 J9 OPT MATER JI Opt. Mater. PD FEB PY 2008 VL 30 IS 6 BP 993 EP 1000 DI 10.1016/j.optmat.2007.05.027 PG 8 WC Materials Science, Multidisciplinary; Optics SC Materials Science; Optics GA 268XC UT WOS:000253612500029 ER PT J AU Sidick, E Green, JJ Morgan, RM Ohara, CM Redding, DC AF Sidick, Erkin Green, Joseph J. Morgan, Rhonda M. Ohara, Catherine M. Redding, David C. TI Adaptive cross-correlation algorithm for extended scene Shack-Hartmann wavefront sensing SO OPTICS LETTERS LA English DT Article AB We present an adaptive cross-correlation algorithm for a large dynamic range extended-scene Shack-Hartmann wavefront sensor. We show that it accurately measures very fine image shifts over many pixels under a variety of practical imaging conditions. (C) 2008 Optical Society of America. C1 [Sidick, Erkin; Green, Joseph J.; Morgan, Rhonda M.; Ohara, Catherine M.; Redding, David C.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sidick, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Erkin.Sidick@jpl.nasa.gov RI Tippie, Abbie/A-1106-2007 NR 8 TC 8 Z9 10 U1 3 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 1 PY 2008 VL 33 IS 3 BP 213 EP 215 DI 10.1364/OL.33.000213 PG 3 WC Optics SC Optics GA 266AW UT WOS:000253404300004 PM 18246132 ER PT J AU Goward, SN Underwood, LW Fletcher, R Holekamp, K Pagnutd, M Ryan, RE Fearon, MG Hurtt, G Garvin, J Jensen, J Nolan, M Stanley, T Frisbie, TE Swearingen, W AF Goward, Samuel N. Underwood, Lauren W. Fletcher, Rose Holekamp, Kara Pagnutd, Mary Ryan, Robert E. Fearon, Matthew G. Hurtt, George Garvin, Jim Jensen, John Nolan, Matt Stanley, Thomas Frisbie, Troy E. Swearingen, Will TI NASA's Earth science use of commercially available remote sensing datasets SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID CARBONATE TIDAL FLAT; REPUBLIC-OF-KOREA; SPATIAL-RESOLUTION; IKONOS IMAGERY; SATELLITE-OBSERVATIONS; IMPERVIOUS SURFACES; MALARIA CONTROL; LANDSAT ETM+; AREA; VALIDATION C1 [Goward, Samuel N.] Univ Maryland, Dept Geophys, Washington, DC 20242 USA. [Underwood, Lauren W.; Fletcher, Rose; Holekamp, Kara; Pagnutd, Mary; Ryan, Robert E.] Sci Syst & Appl Inc, Stennis Space Ctr, MS 39529 USA. [Fearon, Matthew G.; Hurtt, George] Univ New Hampshire, Inst Study Earth Oceans, Durham, NH 03824 USA. [Garvin, Jim] Goddard Space Flight Ctr, Sci Explorat Directorate, Greenbelt, MD 20771 USA. [Jensen, John] Univ S Carolina, Ctr GIS & Remote Sensing, Dept Geog, Columbia, SC 29208 USA. [Garvin, Jim] Off Space Sci, Washington, DC 20546 USA. [Nolan, Matt] Univ Alaska Fairbanks, Water & Environm Res Ctr, Inst No Engn, Fairbanks, AK 99775 USA. [Stanley, Thomas; Frisbie, Troy E.] NASA, Appl Res & Technol Project Off, Earth Sci Appl Directorate, Stennis Space Ctr, MS 39529 USA. [Swearingen, Will] Montana State Univ, TechLink Ctr, Bozeman, MT 59718 USA. RP Goward, SN (reprint author), Univ Maryland, Dept Geophys, 2181 LeFrak Hall, Washington, DC 20242 USA. RI Hurtt, George/A-8450-2012 NR 51 TC 1 Z9 1 U1 1 U2 5 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD FEB PY 2008 VL 74 IS 2 BP 138 EP 146 PG 9 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 263FR UT WOS:000253203500001 ER PT J AU Alberi, K Blacksberg, J Bell, LD Nikzad, S Yu, KM Dubon, OD Walukiewicz, W AF Alberi, K. Blacksberg, J. Bell, L. D. Nikzad, S. Yu, K. M. Dubon, O. D. Walukiewicz, W. TI Band anticrossing in highly mismatched Sn(x)Ge(1-x) semiconducting alloys SO PHYSICAL REVIEW B LA English DT Article ID GAP AB We show that at dilute Sn concentrations (x < 10%), the composition dependence of the direct band gap and spin-orbit splitting energies of Sn(x)Ge(1-x) can be described by a valence band anticrossing model. Hybridization of the extended and localized p-like states of the Ge host matrix and the Sn minority atoms, respectively, leads to a restructuring of the valence band into E(+) and E(-) subbands. The notably large reduction in the band gap follows from an upward shift in the valence band edge by approximately 22 meV per x=0.01. These results demonstrate that like III-V and II-VI compound semiconductors, group IV elements may form highly mismatched alloys in which the band anticrossing phenomenon is responsible for their unique properties. C1 [Alberi, K.; Yu, K. M.; Dubon, O. D.; Walukiewicz, W.] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. [Alberi, K.; Dubon, O. D.] Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. [Blacksberg, J.; Bell, L. D.; Nikzad, S.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Alberi, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012 OI Yu, Kin Man/0000-0003-1350-9642 NR 15 TC 46 Z9 46 U1 2 U2 17 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD FEB PY 2008 VL 77 IS 7 AR 073202 DI 10.1103/PhysRevB.77.073202 PG 4 WC Physics, Condensed Matter SC Physics GA 271BP UT WOS:000253764200006 ER PT J AU Schnittman, JD Buonanno, A van Meter, JR Baker, JG Boggs, WD Centrella, J Kelly, BJ McWilliams, ST AF Schnittman, Jeremy D. Buonanno, Alessandra van Meter, James R. Baker, John G. Boggs, William D. Centrella, Joan Kelly, Bernard J. McWilliams, Sean T. TI Anatomy of the binary black hole recoil: A multipolar analysis SO PHYSICAL REVIEW D LA English DT Article ID GRAVITATIONAL-RADIATION RECOIL; ADAPTIVE MESH REFINEMENT; QUASI-NORMAL MODES; NUMERICAL RELATIVITY; SPHERICAL-HARMONICS; COMPACT BINARIES; INITIAL DATA; WAVES; ORDER; MOMENTUM AB We present a multipolar analysis of the gravitational recoil computed in recent numerical simulations of binary black hole coalescence, for both unequal masses and nonzero, nonprecessing spins. We show that multipole moments up to and including center dot=4 are sufficient to accurately reproduce the final recoil velocity (within similar or equal to 2%) and that only a few dominant modes contribute significantly to it (within similar or equal to 5%). We describe how the relative amplitudes, and more importantly, the relative phases, of these few modes control the way in which the recoil builds up throughout the inspiral, merger, and ringdown phases. We also find that the numerical results can be reproduced by an "effective Newtonian" formula for the multipole moments obtained by replacing the radial separation in the Newtonian formulas with an effective radius computed from the numerical data. Beyond the merger, the numerical results are reproduced by a superposition of three Kerr quasinormal modes. Analytic formulas, obtained by expressing the multipole moments in terms of the fundamental quasinormal modes of a Kerr black hole, are able to explain the onset and amount of "antikick" for each of the simulations. Lastly, we apply this multipolar analysis to help explain the remarkable difference between the amplitudes of planar and nonplanar kicks for equal-mass spinning black holes. C1 [Schnittman, Jeremy D.; Buonanno, Alessandra] Univ Maryland, Dept Phys, Maryland Ctr Fundamental Phys, College Pk, MD 20742 USA. [van Meter, James R.; Baker, John G.; Centrella, Joan; Kelly, Bernard J.] NASA, Goddard Space Flight Ctr, Gravitat Astrophys Lab, Greenbelt, MD 20771 USA. [van Meter, James R.] Univ Maryland Baltimore Cty, Ctr Space Sci & Technol, Baltimore, MD 21250 USA. [Boggs, William D.; McWilliams, Sean T.] Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Schnittman, JD (reprint author), Univ Maryland, Dept Phys, Maryland Ctr Fundamental Phys, College Pk, MD 20742 USA. RI van meter, james/E-7893-2011; Kelly, Bernard/G-7371-2011; Schnittman, Jeremy/D-3168-2012; OI Kelly, Bernard/0000-0002-3326-4454 NR 87 TC 80 Z9 80 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD FEB PY 2008 VL 77 IS 4 AR 044031 DI 10.1103/PhysRevD.77.044031 PG 27 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 271BV UT WOS:000253764800078 ER PT J AU Vallisneri, M AF Vallisneri, Michele TI Use and abuse of the Fisher information matrix in the assessment of gravitational-wave parameter-estimation prospects SO PHYSICAL REVIEW D LA English DT Article ID COALESCING BINARIES; COMPACT BINARIES; SIGNALS AB The Fisher-matrix formalism is used routinely in the literature on gravitational-wave detection to characterize the parameter-estimation performance of gravitational-wave measurements, given parametrized models of the waveforms, and assuming detector noise of known colored Gaussian distribution. Unfortunately, the Fisher matrix can be a poor predictor of the amount of information obtained from typical observations, especially for waveforms with several parameters and relatively low expected signal-to-noise ratios (SNR), or for waveforms depending weakly on one or more parameters, when their priors are not taken into proper consideration. In this paper I discuss these pitfalls; show how they occur, even for relatively strong signals, with a commonly used template family for binary-inspiral waveforms; and describe practical recipes to recognize them and cope with them. Specifically, I answer the following questions: (i) What is the significance of (quasi-)singular Fisher matrices, and how must we deal with them? (ii) When is it necessary to take into account prior probability distributions for the source parameters? (iii) When is the signal-to-noise ratio high enough to believe the Fisher-matrix result? In addition, I provide general expressions for the higher-order, beyond-Fisher-matrix terms in the 1/SNR expansions for the expected parameter accuracies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vallisneri, M (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 35 TC 148 Z9 148 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD FEB PY 2008 VL 77 IS 4 AR 042001 DI 10.1103/PhysRevD.77.042001 PG 20 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 271BV UT WOS:000253764800004 ER PT J AU Rouson, DWI Kassinos, SC Moulitsas, I Sarris, IE Xu, X AF Rouson, D. W. I. Kassinos, S. C. Moulitsas, I. Sarris, I. E. Xu, X. TI Dispersed-phase structural anisotropy in homogeneous magnetohydrodynamic turbulence at low magnetic Reynolds number SO PHYSICS OF FLUIDS LA English DT Article ID DEVELOPED CHANNEL FLOW; PREFERENTIAL CONCENTRATION; ISOTROPIC TURBULENCE; PARTICLES AB A new tensor statistic, the dispersed-phase structure dimensionality D-p, is defined to describe the preferred orientation of clusters of discrete bodies. The evolution of D-p is calculated via direct numerical simulations of passive, Stokesian particles driven by initially isotropic, decaying magnetohydrodynamic turbulence. Results are presented for five magnetic field strengths as characterized by magnetic interaction parameters, N, in the range 0-50. Four field strengths are studied at a grid resolution of 128(3). The strongest field strength is also studied at 256(3) resolution. In each case, the externally applied magnetic field was spatially uniform and followed a step function in time. Particles with initially uniform distributions were tracked through hydrodynamic turbulence for up to 2800 particle response times before the step change in the magnetic field. In the lower resolution simulation, the particle response time, tau(p), matched the Kolmogorov time scale at the magnetic field application time t(0). The higher-resolution simulation tracked ten sets of particles with tau(p) spanning four decades bracketing the Kolmogorov time scale and the Joule time. The results demonstrate that D-p distinguishes between uniformly distributed particles, those organized into randomly oriented clusters, and those organized into two-dimensional sheets everywhere tangent to the magnetic field lines. Lumley triangles are used to demonstrate that the degree of structural anisotropy depends on tau(p), N, and the time span over which the magnetic field is applied. (D American Institute of Physics. C1 [Rouson, D. W. I.] USN, Res Lab, Multiphy Modeling Sect, Washington, DC 20375 USA. [Kassinos, S. C.] NASA Ames, Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. [Kassinos, S. C.; Moulitsas, I.] Univ Cyprus, Dept Mech & Manufacturing Engn, CY-1678 Nicosia, Cyprus. [Sarris, I. E.] Univ Libre Brussels, B-1050 Brussels, Belgium. [Xu, X.] Gen Motors Corp, Pontiac, MI 48340 USA. RP Rouson, DWI (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. EM rouson@sandia.gov; kassinos@ucy.ac.cy; moulitsa@ucy.ac.cy; xiaofeng.xu@gm.com RI Moulitsas, Irene/B-1558-2009; Kassinos, Stavros/B-6404-2016 OI Kassinos, Stavros/0000-0002-3501-3851 NR 44 TC 7 Z9 7 U1 2 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 EI 1089-7666 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 2008 VL 20 IS 2 AR 025101 DI 10.1063/1.2832776 PG 19 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 276KZ UT WOS:000254141600023 ER PT J AU Shebalin, JV AF Shebalin, John V. TI The homogeneous turbulent dynamo SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOHYDRODYNAMIC TURBULENCE; BROKEN ERGODICITY; MAGNETIC-FIELDS AB Ideal, homogeneous, magnetohydrodynarnic turbulence is represented by finite Fourier series whose coefficients form a canonical ensemble. Here, the relevant statistical theory is substantially extended. This includes finding eigenvalues and eigenvectors of the covariance matrix for each modal probability density. The eigenvectors allow for a special unitary transformation of phase space coordinates into a set of eigenvariables. The smallest eigenvalues occur at the lowest wavenumber and are associated with three dominant eigenvectors. The lowest wavenumber eigenvariables, in statistical equilibrium, are seen to have large mean values containing significant energy and thus define a homogeneous turbulent dynamo. These large mean values arise because the symmetry of phase space is dynamically broken. Nonzero viscosity and magnetic diffusivity are expected to have minimal effect, since this coherent structure exists at the lowest wavenumber, where dissipation is least. C1 [Shebalin, John V.] Univ Houston Clear Lake, Sch Sci & Comp Engn, Houston, TX 77058 USA. [Shebalin, John V.] NASA, Lyndon B Johnson Space Ctr, USA & Astromat Res & Explorat Sci Off, Houston, TX 77058 USA. RP Shebalin, JV (reprint author), Univ Houston Clear Lake, Sch Sci & Comp Engn, Houston, TX 77058 USA. NR 20 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2008 VL 15 IS 2 AR 022305 DI 10.1063/1.2841035 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 276KY UT WOS:000254141500015 ER PT J AU Zenitani, S Hesse, M AF Zenitani, S. Hesse, M. TI The role of the Weibel instability at the reconnection jet front in relativistic pair plasma reconnection SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC-FIELD GENERATION; ACTIVE GALACTIC NUCLEI; RAY BURST SOURCES; PARTICLE-ACCELERATION; COLLISIONLESS RECONNECTION; CURRENT SHEET; PULSAR WIND; DISSIPATION; SHOCKS; SIMULATIONS AB The role of the Weibel instability is investigated for the first time in the context of the large-scale magnetic reconnection problem. A late-time evolution of magnetic reconnection in relativistic pair plasmas is demonstrated by particle-in-cell simulations. In the outflow regions, powerful reconnection jets pile up the magnetic fields and then a contact discontinuity appears there. Further downstream, it is found that the two-dimensional extension of the relativistic Weibel instability generates electromagnetic fields, which are comparable to the antiparallel or piled-up fields. In a microscopic viewpoint, the instability allows the plasma's multiple interactions with the discontinuity. In a macroscopic viewpoint, the instability leads to rapid expansion of the current sheet and then the reconnection jet front further propagates into the downstream. Possible application to the three-dimensional case is briefly discussed. (c) 2008 American Institute of Physics. C1 [Zenitani, S.; Hesse, M.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zenitani, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM zenitani@lssp-mail.gsfc.nasa.gov RI Hesse, Michael/D-2031-2012; Zenitani, Seiji/D-7988-2013; NASA MMS, Science Team/J-5393-2013 OI Zenitani, Seiji/0000-0002-0945-1815; NASA MMS, Science Team/0000-0002-9504-5214 NR 42 TC 25 Z9 25 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD FEB PY 2008 VL 15 IS 2 AR 022101 DI 10.1063/1.2836623 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 276KY UT WOS:000254141500002 ER PT J AU Titus, TN Colaprete, A Prettyman, TH AF Titus, Timothy N. Colaprete, Anthony Prettyman, Thomas H. TI Introduction to planetary and space science special issue: Mars polar processes SO PLANETARY AND SPACE SCIENCE LA English DT Editorial Material ID SEASONAL CAP; WATER ICE; TES C1 [Titus, Timothy N.] US Geol Survey, Flagstaff, AZ 86001 USA. [Colaprete, Anthony] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Prettyman, Thomas H.] Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Titus, TN (reprint author), US Geol Survey, 2255 N Gemini Dr, Flagstaff, AZ 86001 USA. EM ttitus@usgs.gov OI Prettyman, Thomas/0000-0003-0072-2831 NR 10 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 147 EP 149 DI 10.1016/j.pss.2007.08.002 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500001 ER PT J AU Colaprete, A Barnes, JR Haberle, RM Montmessin, F AF Colaprete, Anthony Barnes, Jeffrey R. Haberle, Robert M. Montmessin, Franck TI CO2 clouds, CAPE and convection on Mars: Observations and general circulation modeling SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; carbon dioxide; clouds; convection; GCM ID CARBON-DIOXIDE CLOUDS; WATER ICE CLOUDS; MARTIAN ATMOSPHERE; GLOBAL SURVEYOR; SOUTH-POLE; SIMULATIONS; VARIABILITY; DYNAMICS; CYCLE; SNOW AB The thermal emission spectrometer (TES) and the radio science (RS) experiment flying on board the Mars Global Surveyor (MGS) spacecraft have made observations of atmospheric temperatures below the saturation temperature of carbon dioxide (CO2). This supersaturated air provides a source of convective available potential energy (CAPE), which, when realized may result in vigorous convective mixing. To this point, most Mars atmospheric models have assumed vertical mixing only when the dry adiabatic lapse rate is exceeded. Mixing associated with the formation of CO2 clouds could have a profound effect on the vertical structure of the polar night, altering the distribution of temperature, aerosols, and gasses. Presented in this work are estimates of the total planetary inventory of CAPE and the potential convective energy flux (PCEF) derived from RS and TES temperature profiles. A new Mars Global Circulation Model (MGCM) CO2 cloud model is developed to better understand the distribution of observed CAPE and its potential effect on Martian polar dynamics and heat exchange, as well as effects on the climate as a whole. The new CO2 cloud model takes into account the necessary cloud microphysics that allow for supersaturation to occur and includes a parameterization for CO2 cloud convection. It is found that when CO2 cloud convective mixing is included, model results are in much better agreement with the observations of the total integrated CAPE as well as total column non-condensable gas concentrations presented by Sprague et al. [2005a, GRS measurements of Ar in Mars' atmosphere, American Astronomical Society, DPS meeting #37, #24.08.. and 2005b, Distribution and Abundance of Mars' Atmospheric Argon.. 36th Annual Lunar and Planetary Science Conference, #2085] When the radiative effects of water ice clouds are included the agreement is further improved. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Colaprete, Anthony; Haberle, Robert M.] NASA, Ames Res Ctr, Planetary Syst Branch, Div Space Sci, Moffett Field, CA 94035 USA. [Barnes, Jeffrey R.] Oregon State Univ, Coll Oceanog & Atmospher Sci, Corvallis, OR 97331 USA. [Montmessin, Franck] IPSL, CNRS, Serv Aeron, F-75252 Paris, France. RP Colaprete, A (reprint author), NASA, Ames Res Ctr, Planetary Syst Branch, Div Space Sci, Moffett Field, CA 94035 USA. EM Anthony.Colaprete-I@nasa.gov; tonyc@freeze.arc.nasa.gov NR 55 TC 30 Z9 30 U1 2 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 150 EP 180 DI 10.1016/j.pss.2007.08.010 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500002 ER PT J AU Bonev, BP Hansen, GB Glenar, DA James, PB Bjorkman, JE AF Bonev, Boncho P. Hansen, Gary B. Glenar, David A. James, Philip B. Bjorkman, Jon E. TI Albedo models for the residual south polar cap on Mars: Implications for the stability of the cap under near-perihelion global dust storm conditions SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; polar caps; residual south polar cap; surface albedo; ices; spectroscopy; atmospheric dust; radiative transfer; dust storms ID ORBITER CAMERA OBSERVATIONS; WATER ICE; CARBON-DIOXIDE; OBSERVATIONAL EVIDENCE; SUMMER TEMPERATURES; OPTICAL-CONSTANTS; THERMAL STRUCTURE; SPECTRAL ALBEDO; BEHAVIOR; VARIABILITY AB It is uncertain whether the residual (perennial) south polar cap on Mars is a transitory or a permanent feature in the current Martian climate. While there is no firm evidence for complete disappearance of the cap in the past, clearly observable changes have been documented. Observations suggest that the perennial cap lost more CO2 material in the spring/summer season prior to the Mariner 9 mission than in those same seasons monitored by Viking and Mars Global Surveyor. In this paper we examine one process that may contribute to these changes-the radiative effects of a planet encircling dust storm that starts during late Martian southern spring on the stability of the perennial south polar cap. To approach this, we model the radiative transfer through a dusty planetary atmosphere bounded by a sublimating CO2 surface. A critical parameter for this modeling is the surface albedo spectrum from the near-UV to the thermal-IR, which was determined from both space-craft and Earth-based observations covering multiple wavelength regimes. Such a multi-wavelength approach is highly desirable since one spectral band by itself cannot tightly constrain the three-parameter space for polar surface albedo models, namely photon "scattering length" in the CO2 ice and the amounts of intermixed water and dust. Our results suggest that a planet-encircling dust storm with onset near solstice can affect the perennial cap's stability, leading to advanced sublimation in a "dusty" year. Since the total amount of solid Co-2 removed by a single storm may be less than the total CO2 thickness, a series of dust storms would be required to remove the entire residual CO2 ice layer from the south perennial cap. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Bonev, Boncho P.; Bjorkman, Jon E.] Univ Toledo, Dept Phys & Astron, Ritter Astrophys Res Ctr, Toledo, OH 43606 USA. [Bonev, Boncho P.; Glenar, David A.] NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. [Hansen, Gary B.] Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. [James, Philip B.] Space Sci Inst, Boulder, CO 80301 USA. RP Bonev, BP (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM bbonev@ssedmail.gsfc.nasa.gov NR 59 TC 12 Z9 12 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 181 EP 193 DI 10.1016/j.pss.2007.08.003 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500003 ER PT J AU Byrne, S Zuber, MT Neumann, GA AF Byrne, S. Zuber, M. T. Neumann, G. A. TI Interannual and seasonal behavior of Martian residual ice-cap albedo SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; polar; ice; albedo; radiometry; interannual ID SOUTH POLAR-CAP; ORBITER LASER ALTIMETER; EMISSION SPECTROMETER EXPERIMENT; GLOBAL SURVEYOR MISSION; WATER ICE; CARBON-DIOXIDE; SUMMER TEMPERATURES; CAMERA OBSERVATIONS; GRAIN-SIZE; MARS AB The Mars Orbiter Laser Altimeter (MOLA), functioning as a high-resolution radiometer, has observed several appearances of the Martian residual ice caps. We examine these data to quantify both seasonal behavior and interannual differences. The northern residual cap (NRC) was found to be mostly stable with the exception of one, previously identified, region of strong variability. Interannual change in the extent of the NRC appears to be small and reversible on timescales of I or 2 years. The NRC has an elaborate seasonal evolution of albedo. Annuli of fine-grained CO2 and water frost, which track the inner and outer edges of the seasonal CO2 cap, cause large temporary brightenings. The NRC albedo is stable from just after solstice to L-s 150 degrees, after which albedo decreases steadily. This late-summer darkening can be explained by shadowing within the rough topography of the NRC, leading to a lower limit on topographic relief of 80cm. The southern residual cap (SRC) appears stable in extent. As has been previously discovered, its seasonal frost albedo behavior appears to be correlated with insolation. However, residual CO2 appears not to share this characteristic; we use this behavioral difference to infer net deposition of CO2 ice on the SRC during 1 out of 3 years. Uncharacteristically, the SRC abruptly darkens at L-s 320 degrees in I Martian year (year beginning April 2002). Circumstantial evidence suggests atmospheric scattering by dust is responsible. The 2001 alobal dust-storm appears, either, to have had no effect on the polar cap albedos, or, resulted in slightly brighter ice deposits. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Byrne, S.; Zuber, M. T.; Neumann, G. A.] Univ Arizona, Lunar & Planetary Lab, Dept Earth Atmospher & Planetary Sci, Tucson, AZ 85721 USA. [Zuber, M. T.; Neumann, G. A.] NASA, Goddard Space Flight Ctr, Terr Phys Lab, Washington, DC USA. RP Byrne, S (reprint author), Univ Arizona, Lunar & Planetary Lab, Dept Earth Atmospher & Planetary Sci, Tucson, AZ 85721 USA. EM shane@lpl.arizona.edu RI Byrne, Shane/B-8104-2012; Neumann, Gregory/I-5591-2013 OI Neumann, Gregory/0000-0003-0644-9944 NR 62 TC 17 Z9 17 U1 3 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 194 EP 211 DI 10.1016/j.pss.2006.03.018 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500004 ER PT J AU Tamppari, LK Smith, MD Bass, DS Hale, AS AF Tamppari, L. K. Smith, M. D. Bass, D. S. Hale, A. S. TI Water-ice clouds and dust in the north polar region of Mars using MGS TES data SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; water ice; clouds; dust; north polar; MGS; TES; mars atmosphere ID THERMAL EMISSION SPECTROMETER; ORBITER CAMERA OBSERVATIONS; INTERANNUAL VARIABILITY; STORM ZONES; SURFACE; TEMPERATURES; ATMOSPHERE AB Water-ice and dust optical depths in Mars' north polar region are mapped as function of season, latitude and longitude, and their characteristics and variability on a geographic, seasonal, and interannual basis are discussed. We use water-ice and dust optical depth data provided by the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES), covering nearly three northern spring and summer periods. We find that interannual variability exists in both the water ice and dust behavior, although there are trends that repeat year to year as well. The optical thickness of the north polar hood (NPH) exhibits interannually varying longitudinal structure, both during springtime recession and late-summer onset. We define the characteristics associated with the transition to and from the NPH and find that the disappearance occurs near L-s = 75 degrees and the reappearance near L-s = 160-165 degrees. We find that the late spring to early summer time frame is characterized by very low water-ice optical depths and enhanced dust activity, with a preference for lower water-ice and higher dust optical depths in the 0-90 degrees W quadrant. We see possible evidence for stationary wavenumber 2 systems in a few of the maps examined. (c) 2007 Published by Elsevier Ltd. C1 [Tamppari, L. K.; Bass, D. S.; Hale, A. S.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Smith, M. D.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tamppari, LK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM leslie.tamppari@jpl.nasa.gov; Michael.D.Smith@nasa.gov; Deborah.S.Bass@jpl.nasa.gov; Amy.S.Hale@jpl.nasa.gov RI Smith, Michael/C-8875-2012 NR 33 TC 18 Z9 18 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 227 EP 245 DI 10.1016/j.pss.2007.08.011 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500006 ER PT J AU Hecht, MH AF Hecht, Michael H. TI The texture of condensed CO2 on the martian polar caps SO PLANETARY AND SPACE SCIENCE LA English DT Article DE mars; carbon dioxide; ice; climate; atmosphere ID SNOW DEPTH; MARS; ICE; WINTER; FROST; WATER; MODEL AB The widespread deposition of CO2 ice on the martian polar caps in winter is readily visible from Earth and has been extensively studied from orbit. As the surface cools during polar night, CO2 condenses directly out of the atmosphere at a rate that establishes equilibrium between radiative loss and latent heat of condensation. Since radiative loss is strongly geometry-dependent, the CO2 frost will grow most rapidly on exposed surfaces and more slowly in depressions. Positive feedback will cause a dramatic enhancement of the relief of the underlying topography and a corresponding reduction in the average bulk density. The resulting surface will be highly textured and riddled with perforations. (c) 2007 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hecht, MH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM michael.h.hecht@jpl.nasa.gov NR 14 TC 2 Z9 2 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 246 EP 250 DI 10.1016/j.pss.2007.08.009 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500007 ER PT J AU Haberle, RM Forget, F Colaprete, A Schaeffer, J Boynton, WV Kelly, NJ Chamberlain, MA AF Haberle, Robert M. Forget, Francois Colaprete, Anthony Schaeffer, James Boynton, William V. Kelly, Nora J. Chamberlain, Matthew A. TI The effect of ground ice on the Martian seasonal CO2 cycle SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; CO2 cycle; ground ice; polar caps ID GLOBAL DISTRIBUTION; VIKING OBSERVATIONS; SURFACE PRESSURE; SUBSURFACE ICE; MARS ODYSSEY; NEAR-SURFACE; POLAR CAPS; CO-2 CYCLE; CIRCULATION; HYDROGEN AB The mostly carbon dioxide (CO2) atmosphere of Mars condenses and sublimes in the polar regions, giving rise to the familiar waxing and waning of its polar caps. The signature of this seasonal CO2 cycle has been detected in surface pressure measurements from the Viking and Pathfinder landers. The amount Of CO2 that condenses during fall and winter is controlled by the net polar energy loss, which is dominated by emitted infrared radiation from the cap itself. However, models of the CO2 cycle match the surface pressure data only if the emitted radiation is artificially suppressed suggesting that they are missing a heat source. Here we show that the missing heat source is the conducted energy coming from soil that contains water ice very close to the surface. The presence of ice significantly increases the thermal conductivity of the ground such that more of the solar energy absorbed at the surface during summer is conducted downward into the ground where it is stored and released back to the surface during fall and winter thereby retarding the CO2 condensation rate. The reduction in the condensation rate is very sensitive to the depth of the soil/ice interface, which our models suggest is about 8 cm in the Northern Hemisphere and I I cm in the Southern Hemisphere. This is consistent with the detection of significant amounts of polar ground ice by the Mars Odyssey Gamma Ray Spectrometer and provides an independent means for assessing how close to the surface the ice must be. Our results also provide an accurate determination of the global annual mean size of the atmosphere and cap CO2 reservoirs, which are, respectively, 6.1 and 0.9 hPa. They also indicate that general circulation models will need to account for the effect of ground ice in their simulations of the seasonal CO2 cycle. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Haberle, Robert M.; Colaprete, Anthony] NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. [Forget, Francois] Univ Paris 06, Inst Pierre Simon Loplace, Meteorol Dynam Lab, F-75252 Paris 06, France. [Schaeffer, James] Raytheon Co, QSSS, Palo Alto, CA USA. [Boynton, William V.; Kelly, Nora J.; Chamberlain, Matthew A.] Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. RP Haberle, RM (reprint author), NASA, Ames Res Ctr, Space Sci & Astrobiol Div, MS 245-3, Moffett Field, CA 94035 USA. EM Robert.M.Haberle@nasa.gov RI Chamberlain, Matthew/D-4805-2012 NR 32 TC 32 Z9 32 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 251 EP 255 DI 10.1016/j.pss.2007.08.006 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500008 ER PT J AU Wagstaft, KL Titus, TN Ivanova, AB Castano, R Bandfield, JL AF Wagstaft, Kiri L. Titus, Timothy N. Ivanova, Anton B. Castano, Rebecca Bandfield, Joshua L. TI Observations of the north polar water ice annulus on Mars using THEMIS and TES SO PLANETARY AND SPACE SCIENCE LA English DT Article DE mars polar caps; water ice; seasonal ice; THEMIS; TES ID SUMMER TEMPERATURES; CO2 FROST; SURFACE; CYCLE; CAP AB The Martian seasonal CO2 ice caps advance and retreat each year. In the spring, as the CO2 cap gradually retreats, it leaves behind an extensive defrosting zone from the solid CO2 cap to the location where all CO2 frost has sublimated. We have been studying this phenomenon in the north polar region using data from the THermal EMission Imaging System (THEMIS), a visible and infra-red (IR) camera on the Mars Odyssey spacecraft, and the Thermal Emission Spectrometer (TES) on Mars Global Surveyor. Recently, we discovered that some THEMIS images of the CO2 defrosting zone contain evidence for a distinct defrosting phenomenon: some areas just south of the CO2 cap edge are too bright in visible wavelengths to be defrosted terrain, but too warm in the IR to be CO2 ice. We hypothesize that we are seeing evidence for a seasonal annulus of water ice (frost) that recedes with the seasonal CO2 cap, as predicted by previous workers. In this paper, we describe our observations with THEMIS and compare them to simultaneous observations by TES and OMEGA. All three instruments find that this phenomenon is distinct from the CO2 cap and most likely composed of water ice. We also find strong evidence that the annulus widens as it recedes. Finally, we show that this annulus can be detected in the raw THEMIS data as it is collected, enabling future long-term onboard monitoring. (c) 2007 Published by Elsevier Ltd. C1 [Wagstaft, Kiri L.; Ivanova, Anton B.; Castano, Rebecca] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Titus, Timothy N.] US Geol Survey, Flagstaff, AZ 86001 USA. [Bandfield, Joshua L.] Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RP Wagstaft, KL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kiri.wagstaff@jpl.nasa.gov RI Ivanov, Anton/C-8944-2014; OI Ivanov, Anton/0000-0001-8376-8581; Wagstaff, Kiri/0000-0003-4401-5506 NR 25 TC 23 Z9 23 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 256 EP 265 DI 10.1016/j.pss.2007.08.008 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500009 ER PT J AU Milkovich, SM Head, JW Neukum, G AF Milkovich, Sarah M. Head, James W., III Neukum, Gerhard CA HRSC Co-Investigator Team TI Stratigraphic analysis of the northern polar layered deposits of Mars: Implications for recent climate history SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; polar caps; polar layered deposits; climate ID ICE AGES; ASTRONOMICAL THEORY; SURFACE; FLOW; CAP; SUBLIMATION; RHEOLOGY; REGION AB We examine the stratigraphy of the polar layered deposits (PLD) within the north polar cap of Mars to assess its layer continuity, correlations, cyclicity and structure and implications for the recent climate record. PLD sequences characterized using Fourier analysis and curve shape matching algorithms show that layers correlate throughout the upper part of the PLD. We tested for cyclicity and found that the uppermost similar to 300 in contain a dominant wavelength layer packet of similar to 30 in, interpreted to be a climate signal related to the 51 kyr precession cycle. Directly below this region we document a section of polar layered deposits similar to 100 m thick without a dominant periodic sianal; this is interpreted to represent a phase of low net accumulation and lag deposits formed during the last ice age, about 0.5-2 Ma ago. We further analyzed layer structure by combining these results with three-dimensional determinations of layer orientation (strike and dip) to assess the internal stratigraphy of the PLD and its implications for polar history. We show that individual layers within the PLD stratigraphy are not horizontal (no dip) but rather show broad variation in elevation with distance. Correlations suggest that the layer strikes and dips broadly follow present cap surface topography. Local variations in layer orientations in the vicinity of the troughs suggest that (1) trough structures were present at the time of layer accumulation and (2) dips may have been influenced by ice flow and/or static ice accumulation in the presence of preexisting troughs. This new information favors models in which the troughs are long-term structures of the PLD rather than (1) recently eroded into the PLD, or (2) very active and laterally migrating around the PLD. Our results strongly support the hypothesis that significant volumes of polar volatiles are mobilized and transported equator-ward during periods of increased obliquity. Our results predict that the upper similar to 300 in of the north polar PLD accumulated in the last 500 ka, yielding net accumulation rates of similar to 0.06 cm/yr. The presence and albedo of the no periodic signal zone suggest that polar net accumulation rates are very low and that dust rich lag deposits form during periods of sustained high obliquity. Layer sequences in the south polar and equatorial regions are examined and compared to those in the north; rhythmic sequences are observed in both regions but no direct correlations to the dominant signals of the north polar deposits have yet been found. These new techniques and observations provide a paradigm for further analysis of recent polar history (the upper kilometer of the record) and a basis for extending assessments to the lower part of the polar deposits and to other cyclic deposits in the geological record of Mars. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Milkovich, Sarah M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Neukum, Gerhard] Free Univ Berlin, Inst Geol Wissenshaften, D-12249 Berlin, Germany. [Milkovich, Sarah M.; Head, James W., III] Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. RP Milkovich, SM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sarah.m.milkovich@jpl.nasa.gov NR 41 TC 24 Z9 24 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD FEB PY 2008 VL 56 IS 2 BP 266 EP 288 DI 10.1016/j.pss.2007.08.004 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 268GO UT WOS:000253567500010 ER PT J AU Li, XY Wang, XF He, K Ma, YQ Su, N He, H Stolc, V Tongprasit, W Jin, WW Jiang, JM Terzaghi, W Li, SG Deng, XW AF Li, Xueyong Wang, Xiangfeng He, Kun Ma, Yeqin Su, Ning He, Hang Stolc, Viktor Tongprasit, Waraporn Jin, Weiwei Jiang, Jiming Terzaghi, William Li, Songgang Deng, Xing Wang TI High-resolution mapping of epigenetic modifications of the rice genome uncovers interplay between DNA methylation, histone methylation, and gene expression SO PLANT CELL LA English DT Article ID NEUROSPORA-CRASSA; ACTIVE GENES; H3 METHYLTRANSFERASE; TRANSCRIPTION; CHROMATIN; CENTROMERE; RNA; HETEROCHROMATIN; ARABIDOPSIS; ELONGATION AB We present high-resolution maps of DNA methylation and H3K4 di- and trimethylation of two entire chromosomes and two fully sequenced centromeres in rice (Oryza sativa) shoots and cultured cells. This analysis reveals combinatorial interactions between these epigenetic modifications and chromatin structure and gene expression. Cytologically densely stained heterochromatin had less H3K4me2 and H3K4me3 and more methylated DNA than the less densely stained euchromatin, whereas centromeres had a unique epigenetic composition. Most transposable elements had highly methylated DNA but no H3K4 methylation, whereas more than half of protein-coding genes had both methylated DNA and di- and/or trimethylated H3K4. Methylation of DNA but not H3K4 was correlated with suppressed transcription. By contrast, when both DNA and H3K4 were methylated, transcription was only slightly reduced. Transcriptional activity was positively correlated with the ratio of H3K4me3/H3K4me2: genes with predominantly H3K4me3 were actively transcribed, whereas genes with predominantly H3K4me2 were transcribed at moderate levels. More protein-coding genes contained all three modifications, and more transposons contained DNA methylation in shoots than cultured cells. Differential epigenetic modifications correlated to tissue-specific expression between shoots and cultured cells. Collectively, this study provides insights into the rice epigenomes and their effect on gene expression and plant development. C1 [Li, Xueyong; Wang, Xiangfeng; He, Hang; Deng, Xing Wang] Natl Inst Biol Sci, Beijing 102206, Peoples R China. [Li, Xueyong; Wang, Xiangfeng; He, Kun; Ma, Yeqin; Su, Ning; Terzaghi, William; Deng, Xing Wang] Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. [Wang, Xiangfeng; He, Kun; Li, Songgang; Deng, Xing Wang] Peking Univ, Coll Life Sci, Peking Yale Joint Res Ctr Plant Mol Genet & Agrob, Beijing 100871, Peoples R China. [Stolc, Viktor; Tongprasit, Waraporn] NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. [Jin, Weiwei; Jiang, Jiming] Univ Wisconsin, Dept Hort, Madison, WI 53706 USA. RP Deng, XW (reprint author), Natl Inst Biol Sci, Beijing 102206, Peoples R China. EM xingwang.deng@yale.edu RI Jiang, Jiming/A-9614-2009; He, Kun/H-3617-2011; He, Kun/F-6322-2012 NR 54 TC 144 Z9 158 U1 8 U2 39 PU AMER SOC PLANT BIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA SN 1040-4651 J9 PLANT CELL JI Plant Cell PD FEB PY 2008 VL 20 IS 2 BP 259 EP 276 DI 10.1105/tpc.107.056879 PG 18 WC Biochemistry & Molecular Biology; Plant Sciences; Cell Biology SC Biochemistry & Molecular Biology; Plant Sciences; Cell Biology GA 308UL UT WOS:000256415400006 PM 18263775 ER PT J AU Bae, H Kim, SH Kim, MS Sicher, RC Lary, D Strem, MD Natarajan, S Bailey, BA AF Bae, Hanhong Kim, Soo-Hyung Kim, Moon S. Sicher, Richard C. Lary, David Strem, Mary D. Natarajan, Savithiry Bailey, Bryan A. TI The drought response of Theobroma cacao (cacao) and the regulation of genes involved in polyamine biosynthesis by drought and other stresses SO PLANT PHYSIOLOGY AND BIOCHEMISTRY LA English DT Article DE polyamine; Theobroma cacao; drought; Nep1; wounding; Phytophthora; ODC; ADC; SAMDC; SPDS; SPMS ID ADENOSYLMETHIONINE DECARBOXYLASE GENES; BLUE-GREEN FLUORESCENCE; EARLY FRUIT-DEVELOPMENT; ORNITHINE-DECARBOXYLASE; ARGININE DECARBOXYLASE; ARABIDOPSIS-THALIANA; DIFFERENTIAL EXPRESSION; PHYTOPHTHORA-MEGAKARYA; FLOWER DEVELOPMENT; MOLECULAR-CLONING AB Drought can negatively impact pod production despite the fact that cacao production usually occurs in tropical areas having high rainfall. Polyamines (PAs) have been associated with the response of plants to drought in addition to their roles in responses to many other stresses. The constitutive and drought inducible expression patterns of genes encoding enzymes involved in PA biosynthesis were determined: an ornithine decarboxylase (TcODC), an arginine decarboxylase (TcADC), an S-adenosylmethionine decarboxylase (TcSAMDC), a spermidine synthase (TcSPDS), and a spermine synthase (TcSPMS). Expression analysis using quantitative real-time reverse transcription-PCR (QPCR) results showed that the PA biosynthesis genes were expressed in all plant tissues examined. Constitutive expression of PA biosynthesis genes was generally highest in mature leaves and open flowers. Expression of TcODC, TcADC, and TcSAMDC was induced with the onset of drought and correlated with changes in stomatal conductance, photosynthesis, photosystem II efficiency, leaf water potential and altered emission of blue-green fluorescence from cacao leaves. Induction of TcSAMDC in leaves was most closely correlated with changes in water potential. The earliest measured responses to drought were enhanced expression of TcADC and TcSAMDC in roots along with decreases in stomatal conductance, photosynthesis, and photosystem II efficiency. Elevated levels of putrescine, spermidine, and spermine were detected in cacao leaves 13 days after the onset of drought. Expression of all five PA associated transcripts was enhanced (1.5-3-fold) in response to treatment with abscisic acid. TcODC and TcADC, were also responsive to mechanical wounding, infection by Phytophthora megakarya (a causal agent of black pod disease in cacao), the necrosis- and ethylene-inducing protein (Nep1) of Fusarium oxysporum, and flower abscission. TcSAMDC expression was responsive to all stresses except flower abscission. TcODC, although constitutively expressed at much lower levels than TcADC, TcSAMDC, TcSPDS, and TcSPMS, was highly inducible by the fungal protein Nep1 (135-fold) and the cacao pathogen Phytophthora megakarya (671-fold). The full length cDNA for ODC was cloned and characterized. Among the genes studied, TcODC, TcADC, and TcSAMDC were most sensitive to induction by drought in addition to other abiotic and biotic stresses. TcODC, TcADC, and TcSAMDC may share signal transduction pathways and/or the stress induced signal induction pathways may converge at these three genes leading to similar although not identical patterns of expression. It is possible altering PA levels in cacao will result in enhanced tolerance to multiple stresses including drought and disease as has been demonstrated in other crops. Published by Elsevier Masson SAS. C1 [Bae, Hanhong; Kim, Soo-Hyung; Sicher, Richard C.; Strem, Mary D.; Natarajan, Savithiry; Bailey, Bryan A.] USDA ARS, Beltsville Agr Res Ctr, Beltsville, MD 20705 USA. [Kim, Moon S.] Univ Washington, Coll Forest Resources, UW Botan Gardens, Seattle, WA 98195 USA. [Lary, David] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Bailey, BA (reprint author), USDA ARS, Beltsville Agr Res Ctr, Beltsville, MD 20705 USA. EM bryan.bailey@ars.usda.gov RI Lary, David/A-6163-2010; Kim, Soo-Hyung/A-3012-2009 OI Kim, Soo-Hyung/0000-0003-3879-4080 NR 71 TC 46 Z9 50 U1 4 U2 15 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 0981-9428 J9 PLANT PHYSIOL BIOCH JI Plant Physiol. Biochem. PD FEB PY 2008 VL 46 IS 2 BP 174 EP 188 DI 10.1016/j.plaphy.2007.10.014 PG 15 WC Plant Sciences SC Plant Sciences GA 276NR UT WOS:000254149700007 PM 18042394 ER PT J AU Polites, M Kalmanson, I Mangus, D AF Polites, M. Kalmanson, I. Mangus, D. TI Solar sail attitude control using small reaction wheels and magnetic torquers SO PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE interplanetary travel; solar sail; solar radiation pressure; attitude control; reaction wheels; magnetic torquers ID RADIATION PRESSURE; SPINNING SPACECRAFT; SYSTEM AB The current paper describes an attitude control system that uses small reaction wheels and magnetic torquers to control the attitude of a large flexible solar sail in low-Earth orbit (LEO). This system is being proposed for the NASA New Millenium Programme Space Technology-9 solar sail technology demonstration mission. Controlling the attitude of a solar sail with these actuators in LEO was previously considered difficult and thus never proposed before. What makes it possible is choosing the right orbit and judiciously constraining the attitude of the solar sail in that orbit. Simulation results are presented that validate this design approach for solar sail attitude control in LEO. C1 [Polites, M.; Kalmanson, I.] Orbital Sci Corp, Space Syst Grp, Dulles, VA 20166 USA. [Mangus, D.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Polites, M (reprint author), Orbital Sci Corp, Space Syst Grp, 21839 Atlant Blvd, Dulles, VA 20166 USA. EM polites.michael@orbital.com NR 34 TC 7 Z9 7 U1 0 U2 6 PU PROFESSIONAL ENGINEERING PUBLISHING LTD PI WESTMINISTER PA 1 BIRDCAGE WALK, WESTMINISTER SW1H 9JJ, ENGLAND SN 0954-4100 J9 P I MECH ENG G-J AER JI Proc. Inst. Mech. Eng. Part G-J. Aerosp. Eng. PD FEB PY 2008 VL 222 IS G1 BP 53 EP 62 DI 10.1243/09544100JAERO250 PG 10 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA 278FR UT WOS:000254270700006 ER PT J AU Parker, PA Anderson-Cook, C Robinson, TJ Liang, L AF Parker, Peter A. Anderson-Cook, Christine Robinson, Timothy J. Liang, Li TI Robust split-plot designs SO QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL LA English DT Article DE design evaluation; D-optimal; IV-optimal; restricted randomization; split-plot designs ID RESPONSE-SURFACE DESIGNS; EQUIVALENT ESTIMATION AB In many experimental situations, practitioners are confronted with costly, time consuming, or hard-to-change (HTC) factors. These practical or economic restrictions on randomization can be accommodated with a split-plot design structure that minimizes the manipulation of the HTC factors. Selecting a good design is a challenging task and requires knowledge of the opportunities and restrictions imposed by the experimental apparatus and an evaluation of statistical performance among competing designs. Building on the well-established evaluation criteria for the completely randomized context, we emphasize the unique qualitative and quantitative evaluation criteria for split-plot designs. An example from hypersonic propulsion research is used to demonstrate the consideration of multiple design evaluation criteria. Published in 2007 by John Wiley & Sons, Ltd. C1 [Parker, Peter A.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. [Anderson-Cook, Christine] Los Alamos Natl Lab, Los Alamos, NM 87545 USA. [Robinson, Timothy J.] Univ Wyoming, Laramie, WY 82071 USA. [Liang, Li] Duke Clin Res Inst, Durham, NC 27705 USA. RP Parker, PA (reprint author), NASA, Langley Res Ctr, Mail Stop 238, Hampton, VA 23681 USA. EM peter.a.parker@nasa.gov NR 25 TC 8 Z9 8 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0748-8017 J9 QUAL RELIAB ENG INT JI Qual. Reliab. Eng. Int. PD FEB PY 2008 VL 24 IS 1 BP 107 EP 121 DI 10.1002/qre.886 PG 15 WC Engineering, Multidisciplinary; Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 277TC UT WOS:000254236600009 ER PT J AU Vanhavere, F Genicot, JL O'Sullivan, D Zhou, D Spurny, F Jadrnickova, I Sawakuchi, GO Yukihara, EG AF Vanhavere, F. Genicot, J. L. O'Sullivan, D. Zhou, D. Spurny, F. Jadrnickova, I. Sawakuchi, G. O. Yukihara, E. G. TI DOsimetry of BIological EXperiments in SPace (DOBIES) with luminescence (OSL and TL) and track etch detectors SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 15th International Conference on Solid State Dosimetry CY JUL 08-13, 2007 CL Delft Univ Technol, Delft, NETHERLANDS HO Delft Univ Technol DE space radiation environment; radiobiology; thermoluminescence; optically stimulated luminescence; track etch detectors ID ALTITUDES; PARTICLES AB The objective of the "DOsimetry of Blological EXperiments in SPace" (DOBIES) project is to develop a standard dosimetric method as a combination of different techniques to estimate absorbed dose, dose equivalent, and linear energy transfer (LET) spectrum in biological samples in space experiments. The detectors investigated in the project include various types of thermoluminescence detectors (TLDs), such as LiF:Mg,Ti, LiF:Mg,Cu,P, CaSO4:Dy, as well as Al2O3:C used as TLD and optically stimulated luminescence detectors (OSLDs), and track-etch detectors (TED). This paper describes the DOBIES project and reports preliminary results obtained during the BASE-A experiment carried out at the International Space Station (ISS) in September, 2006. The results are compared to data from previous space exposures carried out by the members of the DOBIES project. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Sawakuchi, G. O.; Yukihara, E. G.] Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. [Vanhavere, F.; Genicot, J. L.] Belgian Nucl Res Ctr SCK CEN, Mol, Belgium. [O'Sullivan, D.] Inst Adv Studies DIAS, Sch Cosm Phys, Dublin, Ireland. [Zhou, D.] NASA, Lyndon B Johnson Space Ctr, Space Radiat Anal Grp, Houston, TX 77058 USA. [Spurny, F.; Jadrnickova, I.] NPI, Dept Radiat Dosimetry, Prague 818086, Czech Republic. RP Yukihara, EG (reprint author), Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. EM eduardo.yukihara@okstate.edu RI Sawakuchi, Gabriel/A-8961-2009; Ambrozova, Iva/G-9822-2014; Yukihara, Eduardo/F-1345-2014 OI Yukihara, Eduardo/0000-0002-4615-6698 NR 13 TC 15 Z9 15 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD FEB-JUN PY 2008 VL 43 IS 2-6 BP 694 EP 697 DI 10.1016/j.radmeas.2007.12.002 PG 4 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 328OP UT WOS:000257808000121 ER PT J AU Cucinotta, FA Pluth, JM Anderson, JA Harper, JV O'Neill, P AF Cucinotta, Francis A. Pluth, Janice M. Anderson, Jennifer A. Harper, Jane V. O'Neill, Peter TI Biochemical kinetics model of DSB repair and induction of gamma-H2AX foci by non-homologous end joining SO RADIATION RESEARCH LA English DT Article ID DEPENDENT PROTEIN-KINASE; DOUBLE-STRAND BREAKS; HEAT-LABILE SITES; DNA-DAMAGE; HISTONE H2AX; CATALYTIC SUBUNIT; MAMMALIAN-CELLS; HIGH-LET; HUMAN FIBROBLASTS; LIGASE-IV AB We developed a biochemical kinetics approach to describe the repair of double-strand breaks (DSBs) produced by low-LET radiation by modeling molecular events associated with non-homologous end joining (NHEJ). A system of coupled nonlinear ordinary differential equations describes the induction of DSBs and activation pathways for major NHEJ components including Ku70/80, DNA-PKcs, and the ligase IV-XRCC4 heterodimer. The autophosphorylation of DNA-PKcs and subsequent induction of gamma-H2AX foci observed after ionizing radiation exposure were modeled. A two-step model of regulation of repair by DNA-PKcs was developed with an initial step allowing access of other NHEJ components to breaks and a second step limiting access to ligase IV-XRCC4. Our model assumes that the transition from the first to the second step depends on DSB complexity, with a much slower rate for complex DSBs. The model faithfully reproduced several experimental data sets, including DSB rejoining as measured by pulsed-field gel electrophoresis (PFGE) at 10 min postirradiation or longer and quantification of the induction of gamma-H2AX foci. A process that is independent of DNA-PKcs is required for the model to reproduce experimental data for rejoining before 10 min postirradiation. Predictions are made for the behaviors of NHEJ components at low doses and dose rates, and a steady state is found at dose rates of 0.1 Gy/h or lower. (C) 2008 by Radiation Rearch Society. C1 [Cucinotta, Francis A.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. [Pluth, Janice M.] Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. [Anderson, Jennifer A.; Harper, Jane V.; O'Neill, Peter] MRC, Radiat & Genome Stabil Unit, DNA Damage Grp, Didcot OX11 0RD, Oxon, England. RP Cucinotta, FA (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Pkwy, Houston, TX 77058 USA. EM Francis.A.Cucinotta@nasa.aov FU Medical Research Council [G0700730] NR 51 TC 69 Z9 72 U1 0 U2 4 PU RADIATION RESEARCH SOC PI LAWRENCE PA 810 E TENTH STREET, LAWRENCE, KS 66044 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD FEB PY 2008 VL 169 IS 2 BP 214 EP 222 DI 10.1667/RR1035.1 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 255BZ UT WOS:000252633000010 PM 18220463 ER PT J AU Brown, ME Funk, CC AF Brown, Molly E. Funk, Christopher C. TI Climate - Food security under climate change SO SCIENCE LA English DT Editorial Material C1 [Brown, Molly E.] NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. [Funk, Christopher C.] Univ Calif Santa Barbara, Dept Geog, Climate Hazard Grp, Santa Barbara, CA 93106 USA. RP Brown, ME (reprint author), NASA, Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Biospher Sci Branch, Code 614-4, Greenbelt, MD 20771 USA. EM molly.brown@nasa.gov; chris@geog.ucsb.edu RI Brown, Molly/E-2724-2010; zhong, honglin/C-2633-2012; Brown, Molly/M-5146-2013 OI Brown, Molly/0000-0001-7384-3314; Brown, Molly/0000-0001-7384-3314 NR 9 TC 176 Z9 184 U1 6 U2 64 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD FEB 1 PY 2008 VL 319 IS 5863 BP 580 EP 581 DI 10.1126/science.1154102 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 257AQ UT WOS:000252772000029 PM 18239116 ER PT J AU Mane, P Mossi, K Bryant, R AF Mane, Poorna Mossi, Karla Bryant, Robert TI Experimental design and analysis for piezoelectric circular actuators in flow control applications SO SMART MATERIALS & STRUCTURES LA English DT Article ID COMPOSITE CURVED ACTUATORS; SYNTHETIC JETS; LAYER; DELAY AB Flow control can lead to saving millions of dollars in fuel costs each year by making an aircraft more efficient. Synthetic jets, a device for active flow control, operate by introducing small amounts of energy locally to achieve non-local changes in the flow field with large performance gains. These devices consist of a cavity with an oscillating diaphragm that divides it into active and passive sides. The active side has a small opening where a jet is formed, while the passive side does not directly participate in the fluidic jet. Over the years, research has shown that synthetic jet behavior is dependent on the active diaphragm and the cavity design; hence, the focus of this work. The performance of the synthetic jet is studied under various factors related to the diaphragm and the cavity geometry. Three diaphragms, manufactured from piezoelectric composites, were selected for this study: Bimorph, Thunder (R) and Lipca. The overall factors considered are the driving signals, voltage, frequency, cavity height, orifice size, and passive cavity pressure. Using the average maximum jet velocity as the response variable, these factors are individually studied for each actuator, and statistical analysis tools are used to select the relevant factors in the response variable. The factors are divided into two experimental fractional factorial design matrices, with five and four factors, respectively. Both experiments are chosen to be of resolution V, where main factors are confounded with three-factor interactions. In the first experimental design, the results show that frequency is not a significant factor, while waveform is significant for all the actuators. In addition, the magnitude of the regression coefficients suggests that a model that includes the diaphragm as a factor may be possible. These results are valid within the ranges tested, that is low frequencies and sawtooth and sine waveform as driving signals. In the second experimental design, cavity dimensions are kept constant and four factors including back pressure are considered. In this case, each diaphragm produces different results with only one diaphragm, Thunder, showing a definite relationship between the studied factors. The other two diaphragms do not show conclusive results, indicating that there may be other factors that need to be considered when pressure is a concern. In summary, independently of the diaphragm utilized in a synthetic jet actuator, applied waveform is an important factor when maximizing peak jet velocity. In addition, frequency is found not to be significant in all cases within the limits of the study. This indicates that the diaphragm and the driving signal should be included in any optimization design of a piezoelectric synthetic jet actuator. C1 [Mane, Poorna; Mossi, Karla] Virginia Commonwealth Univ, Richmond, VA 23284 USA. [Bryant, Robert] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Mossi, K (reprint author), Virginia Commonwealth Univ, 601 W Main St,Box 843015, Richmond, VA 23284 USA. NR 33 TC 5 Z9 5 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0964-1726 J9 SMART MATER STRUCT JI Smart Mater. Struct. PD FEB PY 2008 VL 17 IS 1 AR 015013 DI 10.1088/0964-1726/17/01/015013 PG 12 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA 276XE UT WOS:000254176200014 ER PT J AU Jiang, HY Halverson, JB AF Jiang, Haiyan Halverson, Jeffrey B. TI On the differences in storm rainfall from hurricanes Isidore and Lili. Part I: Satellite observations and rain potential SO WEATHER AND FORECASTING LA English DT Article ID MICROWAVE SOUNDING UNIT; GLOBAL PRECIPITATION; TRAP TECHNIQUE; RADAR; CLOUD; VALIDATION; RETRIEVAL; SCALES; IMAGER AB It has been well known for years that the heavy rain and flooding of tropical cyclones over land bear a weak relationship to the maximum wind intensity. The rainfall accumulation history and rainfall potential history of two North Atlantic hurricanes during 2002 (Isidore and Lili) are examined using a multisatellite algorithm developed for use with the Tropical Rainfall Measuring Mission (TRMM) dataset. This algorithm uses many channel microwave data sources together with high-resolution infrared data from geosynchronous satellites and is called the real-time Multisatellite Precipitation Analysis (MPA-RT). MPA-RT rainfall estimates during the landfalls of these two storms are compared with the combined U. S. Next-Generation Doppler Radar (NEXRAD) and gauge dataset: the National Centers for Environmental Prediction (NCEP) hourly stage IV multisensor precipitation estimate analysis. Isidore produced a much larger storm total volumetric rainfall as a greatly weakened tropical storm than did category 1 Hurricane Lili during landfall over the same area. However, Isidore had a history of producing a large amount of volumetric rain over the open gulf. Average rainfall potential during the 4 days before landfall for Isidore was over a factor of 2.5 higher than that for Lili. When using the TRMM-based MPA-RT rainfall estimate, results are consistent with a previous study, which analyzed just the infrared-based rain estimation; that is, the rain potential history could be used as a predictor for the storm's potential for inland flooding 3-4 days in advance of landfall. C1 Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21201 USA. NASA, Goddard Space Flight Ctr, Meososcale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Jiang, HY (reprint author), Univ Utah, Dept Meteorol, Rm 819 WBB,135 S 1460 E, Salt Lake City, UT 84112 USA. EM h.jiang@utah.edu NR 33 TC 15 Z9 15 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD FEB PY 2008 VL 23 IS 1 BP 29 EP 43 DI 10.1175/2007WAF2005096.1 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 272QS UT WOS:000253875200003 ER PT J AU Jiang, HY Halverson, JB AF Jiang, Haiyan Halverson, Jeffrey B. TI On the differences in storm rainfall from Hurricanes Isidore and Lili. Part II: Water budget SO WEATHER AND FORECASTING LA English DT Article ID MEASURING MISSION TRMM; ATMOSPHERIC PREDICTION SYSTEM; VERTICAL WIND SHEAR; TROPICAL CYCLONE; ENVIRONMENTAL-INFLUENCES; HYDROMETEOR PROFILES; ANGULAR-MOMENTUM; EDDY FLUXES; PRECIPITATION; SATELLITE AB Part I of this two-part paper examined the satellite-derived rainfall accumulation and rain potential history of Hurricanes Isidore and Lili (2002). This paper (Part II) uses analyses from the Navy Operational Global Atmospheric Prediction System (NOGAPS) to examine the water budget and environmental parameters and their relationship to the precipitation for these two storms. Factors other than storm size are found to account for large volumetric differences in storm total rainfall between Lili and Isidore. It is found that the horizontal moisture convergence was crucial to the initiation and maintenance of Isidore's intense rainfall before and during its landfall. When the storm was over the ocean, the ocean moisture flux (evaporation) was the second dominant term among the moisture sources that contribute to precipitation. During Isidore's life history, the strong horizontal moisture flux convergence corresponded to the large storm total precipitable water. The large difference in budget-derived stored cloud ice and liquid water between Isidore and Lili is corroborated from Tropical Rainfall Measuring Mission (TRMM) measurements. During Isidore's landfall, the decrease in environmental water vapor contributed to rainfall in a very small amount. These results indicate the importance of the environmental precipitable water and moisture convergence and ocean surface moisture flux in generating Isidore's large rainfall volume and inland flooding as compared with Lili's water budget history. Both the moisture convergence and ocean flux were small for Lili. C1 Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21201 USA. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Jiang, HY (reprint author), Univ Utah, Dept Meteorol, Rm 819 WBB,135 S 1460 E, Salt Lake City, UT 84112 USA. EM h.jiang@utah.edu NR 49 TC 13 Z9 13 U1 2 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD FEB PY 2008 VL 23 IS 1 BP 44 EP 61 DI 10.1175/2007WAF2005120.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 272QS UT WOS:000253875200004 ER PT J AU Pu, ZX Li, XL Velden, CS Aberson, SD Liu, WT AF Pu, Zhaoxia Li, Xuanli Velden, Christopher S. Aberson, Sim D. Liu, W. Timothy TI The impact of aircraft dropsonde and satellite wind data on numerical simulations of two landfalling tropical storms during the tropical cloud systems and processes experiment SO WEATHER AND FORECASTING LA English DT Article ID VARIATIONAL DATA ASSIMILATION; CONVECTIVE ADJUSTMENT SCHEME; TROPOSPHERIC WINDS; INTENSITY CHANGE; TRACK FORECASTS; HURRICANE; PREDICTION; MODEL; DROPWINDSONDE; RAINFALL AB Dropwindsonde, Geostationary Operational Environmental Satellite-11 (GOES-11) rapid-scan atmospheric motion vectors, and NASA Quick Scatterometer (QuikSCAT) near-surface wind data collected during NASA's Tropical Cloud Systems and Processes (TCSP) field experiment in July 2005 were assimilated into an advanced research version of the Weather Research and Forecasting (WRF) model using its three-dimensional variational data assimilation (3DVAR) system. The impacts of the mesoscale data assimilation on WRF numerical simulation of Tropical Storms Cindy and Gert (2005) near landfall are examined. Sensitivity of the forecasts to the assimilation of each single data type is investigated. Specifically, different 3DVAR strategies with different analysis update cycles and resolutions are compared in order to identify the better methodology for assimilating the data from research aircraft and satellite for tropical cyclone study. The results presented herein indicate the following. 1) Assimilation of dropwindsonde and satellite wind data into the WRF model improves the forecasts of the two tropical storms up to the landfall time. The QuikSCAT wind information is very important for improving the storm track forecast, whereas the dropwindsonde and GOES-11 wind data are also necessary for improved forecasts of intensity and precipitation. 2) Data assimilation also improves the quantitative precipitation forecasts (QPFs) near landfall of the tropical storms. 3) A 1-h rapid-update analysis cycle at high resolution (9 km) provides more accurate tropical cyclone forecasts than a regular 6-h analysis cycle at coarse (27 km) resolution. The high-resolution rapidly updated 3DVAR analysis cycle might be a practical way to assimilate the data collected from tropical cyclone field experiments. C1 [Pu, Zhaoxia; Li, Xuanli] Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. [Velden, Christopher S.] Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI USA. [Aberson, Sim D.] NOAA, Hurricane Res Div, Miami, FL USA. [Liu, W. Timothy] CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Pu, ZX (reprint author), Univ Utah, Dept Meteorol, 135 S 1460 E,Rm 819, Salt Lake City, UT 84112 USA. EM zhaoxia.pu@utah.edu RI Aberson, Sim/C-4891-2013 OI Aberson, Sim/0000-0002-3670-0100 NR 42 TC 30 Z9 32 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD FEB PY 2008 VL 23 IS 1 BP 62 EP 79 DI 10.1175/2007WAF2007006.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 272QS UT WOS:000253875200005 ER PT J AU Bell, TL Rosenfeld, D Kim, KM Yoo, JM Lee, MI Hahnenberger, M AF Bell, Thomas L. Rosenfeld, Daniel Kim, Kyu-Myong Yoo, Jung-Moon Lee, Myong-In Hahnenberger, Maura TI Midweek increase in US summer rain and storm heights suggests air pollution invigorates rainstorms SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WEEKDAY-WEEKEND DIFFERENCES; DIURNAL CYCLE; PARTICULATE MATTER; HYDROLOGICAL CYCLE; TROPICAL RAINFALL; HEAT RELEASE; PART I; PRECIPITATION; CLOUD; AEROSOL AB Tropical Rainfall Measuring Mission (TRMM) satellite estimates of summertime rainfall over the southeast U. S. are found on average to be significantly higher during the middle of the work week than on weekends, attributable to a midweek intensification of afternoon storms and an increase in area with detectable rain. TRMM radar data show a significant midweek increase in the echo-top heights reached by afternoon storms. Weekly variations in model-reanalysis wind patterns over the region are consistent with changes in convection implied by the satellite data. Weekly variations in rain gauge averages are also consistent with the satellite estimates, though possibly smaller in amplitude. A midweek decrease of rainfall over the nearby Atlantic is also seen. EPA measurements of surface particulate concentrations show a midweek peak over much of the U. S. These observations are consistent with the theory that anthropogenic air pollution suppresses cloud-drop coalescence and early rainout during the growth of thunderstorms over land, allowing more water to be carried above the 0 degrees C isotherm, where freezing yields additional latent heat, invigorating the storms and producing large ice hydrometeors. The enhanced convection induces regional convergence, uplifting and an overall increase of rainfall. Compensating downward air motion suppresses convection over the adjacent ocean areas. Pre-TRMM-era data suggest that the weekly cycle only became strong enough to be detectable beginning in the 1980's. Rain-gauge data also suggest that a weekly cycle may have been detectable in the 1940's, but with peak rainfall on Sunday or Monday, possibly explained by the difference in composition of aerosol pollution at that time. This "weekend effect'' may thus offer climate researchers an opportunity to study the regional climate-scale impact of aerosols on storm development and monsoon-like circulation. C1 [Bell, Thomas L.; Kim, Kyu-Myong; Lee, Myong-In] NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. [Rosenfeld, Daniel] Hebrew Univ Jerusalem, Inst Earth Sci, IL-91904 Jerusalem, Israel. [Kim, Kyu-Myong; Lee, Myong-In] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. [Yoo, Jung-Moon] Ewha Womans Univ, Dept Sci Educ, Seoul 120750, South Korea. [Hahnenberger, Maura] Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. RP Bell, TL (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Mail Code 613-2, Greenbelt, MD 20771 USA. EM thomas.l.bell@nasa.gov; daniel@vms.huji.ac.il; kyu-myong.kim@nasa.gov; yjm@ewha.ac.kr; myong-in.lee@nasa.gov; mhahn@met.utah.edu RI Bell, Thomas/G-5425-2012; Kim, Kyu-Myong/G-5398-2014; Rosenfeld, Daniel/F-6077-2016; OI Rosenfeld, Daniel/0000-0002-0784-7656; Lee, Myong-In/0000-0001-8983-8624 NR 79 TC 111 Z9 116 U1 3 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 31 PY 2008 VL 113 IS D2 AR D02209 DI 10.1029/2007JD008623 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 257UW UT WOS:000252825200004 ER PT J AU Boardsen, SA Green, JL Reinisch, BW AF Boardsen, Scott A. Green, James L. Reinisch, Bodo W. TI Comparison of kilometric continuum latitudinal radiation patterns with linear mode conversion theory SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TERRESTRIAL MYRIAMETRIC RADIATION; NONTHERMAL CONTINUUM; ELECTROMAGNETIC-RADIATION; RADIO WINDOWS; MAGNETOSPHERE; PLASMAPAUSE; EMISSIONS; IONOSPHERE; LOCATION; GEOTAIL AB Using 80 observations of kilometric continuum (KC) radiation patterns detected by the Radio Plasma Imager on the IMAGE spacecraft, the latitudinal variation of these radiation patterns is compared with the predictions of linear mode conversion theory (LMCT). Six of these comparisons are presented in this paper. Because the location and shape of the plasmapause at the source cannot be simultaneously determined with all of the KC observations, we estimated the minimum frequency-dependent beaming angle possible based on a statistical upper limit plasma density versus L-shell profile. This density versus L-shell profile is equated to the 90th percentile plasma density versus L-shell curve derived from over 40,000 in situ measurements of the upper hybrid resonance frequency made over the first 3 years of the IMAGE mission. For all cases, starting at frequencies approximately > 150 kHz, the model beam center was found to lie just within or outside the radiation pattern. Unrealistic peak densities are required at the equatorial source L-shell locations which are necessary to force the beam centers to lie deep within the observed radiation patterns. We present this as strong evidence that LMCT cannot be used to explain KC. In order to explain the latitudinal location of the high-frequency end of these KC radiation patterns a theory is required in which these frequencies are beamed at equatorial angles that are much smaller than the predictions of LMCT. Hashimoto et al. (2005), analyzing one KC radiation pattern detected by CRRES, reached the same conclusion. We present one case in which the source location was inferred by equating the harmonic spacing in the KC radiation pattern with the model electron cyclotron frequency at the source. The LMCT model beams, for this source location, were found to lie outside of the radiation pattern at all frequencies, again consistent with Hashimoto et al. (2005). In addition a survey of KC observations by IMAGE in MLT is presented in which the probability of occurrence peaks in both the dawn and evening sectors. C1 [Green, James L.] NASA Headquarters, Planetary Sci Div, Washington, DC 20546 USA. [Reinisch, Bodo W.] Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. [Boardsen, Scott A.] Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. RP Boardsen, SA (reprint author), NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Code 674 0, Greenbelt, MD 20771 USA. EM scott.boardsen@nasa.gov NR 33 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 31 PY 2008 VL 113 IS A1 AR A01219 DI 10.1029/2007JA012319 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258RK UT WOS:000252887000002 ER PT J AU Hamilton, K Smith, CW Vasquez, BJ Leamon, RJ AF Hamilton, Kathleen Smith, Charles W. Vasquez, Bernard J. Leamon, Robert J. TI Anisotropies and helicities in the solar wind inertial and dissipation ranges at 1 AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; HYDROMAGNETIC WAVE EXCITATION; INTERSTELLAR PICKUP PROTONS; ALFVEN WAVES; KINETIC DISSIPATION; RADIAL EVOLUTION; ION-ACCELERATION; TURBULENCE; FLUCTUATIONS; REFRACTION AB We have constructed a database of ACE observations at 1 AU based on 960 intervals spanning the broadest possible range of solar wind conditions including magnetic clouds. Using spectral analysis of high-resolution magnetic field data we compare inertial range characteristics with properties in the measured dissipation range. We find that previous conclusions by Leamon et al. (1998a, 1998b, 1998c) are upheld: average wave vectors are more field-aligned in the dissipation range than in the inertial range, magnetic fluctuations are less transverse to the mean field in the dissipation range, and cyclotron damping plays an important but not exclusive role in the formation of the dissipation range. However, field-aligned wave vectors play a larger role in the formation of the dissipation range than was previously found. In the process we find significant contrast between these inertial range results and the conclusions of Dasso et al. (2005) who examine larger-scale fluctuations within the inertial range. Dasso et al. found a dominance of field-aligned wave vectors in the high-speed wind and a dominance of quasi-perpendicular (two-dimensional) wave vectors in low-speed winds. We find that the orientation of the wave vectors for the smallest scales within the inertial range are not organized by wind speed and that on average all samples show the same distribution of energy between perpendicular and field-aligned wave vectors. We conclude that this is due to the time required to evolve the spectrum toward a two-dimensional state where the smaller inertial range scales examined here evolve more quickly than the larger scales of earlier analysis. Likewise, we find no such organization within the dissipation range. C1 [Hamilton, Kathleen; Smith, Charles W.; Vasquez, Bernard J.] Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. [Leamon, Robert J.] NASA, Goddard Space Flight Ctr, ADNET Syst Inc, Greenbelt, MD 20771 USA. RP Hamilton, K (reprint author), Univ New Hampshire, Ctr Space Sci, Morse Hall, Durham, NH 03824 USA. EM kmz4@unh.edu; charles.smith@unh.edu; bernie.vasquez@unh.edu; leamon@grace.nascom.nasa.gov NR 63 TC 93 Z9 93 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 31 PY 2008 VL 113 IS A1 AR A01106 DI 10.1029/2007JA012559 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258RK UT WOS:000252887000007 ER PT J AU Weimer, DR King, JH AF Weimer, Daniel R. King, Joseph H. TI Improved calculations of interplanetary magnetic field phase front angles and propagation time delays SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND; DIRECTIONAL DISCONTINUITIES; WEIMER AB It has been known that the variations in the interplanetary magnetic field (IMF) occur within surfaces that are tilted with respect to the solar wind velocity vector. This tilting of the IMF phase fronts may cause the propagation from a point of observation to another location to have delay times that vary substantially. Therefore for accurate delay calculations in real time, or for the creation of scientific data sets, it is necessary to be able to determine the phase surface orientation angles using the magnetic field measurements on one spacecraft only. Methods for calculating these tilt angles have been tested for accuracy by a comparison using IMF measurements on multiple satellites. One method is a variation of the minimum variance of the magnetic field, where it is constrained by the condition that the average field along the phase front's normal vector is zero. This method is referred to as MVAB-0. Another technique is to simply calculate the vector cross product between magnetic fields measured at two different sample times. The choices of the different parameters for the calculation and error discrimination are important. An optimization of parameters was done by testing how well the propagation delays from one spacecraft to others are predicted. The tests have indicated that, when optimized, both procedures work comparably well. It had also been found that further improvements to time delay predictions are obtained by combining together both the MVAB-0 and cross-product techniques, where the results of both methods must be in near agreement. C1 [Weimer, Daniel R.] Solana Sci Inc, Brookline, NH 03033 USA. [King, Joseph H.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [King, Joseph H.] NASA, Goddard Space Flight Ctr, Perot Syst, Greenbelt, MD 20771 USA. RP Weimer, DR (reprint author), Solana Sci Inc, Brookline, NH 03033 USA. EM weimer@solanasci.com NR 21 TC 52 Z9 52 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 31 PY 2008 VL 113 IS A1 AR A01105 DI 10.1029/2007JA012452 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258RK UT WOS:000252887000003 ER PT J AU Muskett, RR Lingle, CS Sauber, JA Rabus, BT Tangborn, WV AF Muskett, Reginald R. Lingle, Craig S. Sauber, Jeanne A. Rabus, Bernhard T. Tangborn, Wendell V. TI Acceleration of surface lowering on the tidewater glaciers of Icy Bay, Alaska, USA from InSAR DEMs and ICESat altimetry SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Alaska; tidewater glaciers; glacier thinning; retreat; ICESat; SRTM; remote sensing ID RADAR TOPOGRAPHY MISSION; MALASPINA GLACIER; CLIMATE-CHANGE; MASS-BALANCE; MODEL AB Much of the increasing rate of glacier wastage observed during the late 20th century is attributed to retreat and thinning of tidewater glaciers grounded below sea level in fiords. We estimate the area-average, i.e. the integrated volume change over glacier area, elevation changes on Guyot, Yahtse and Tyndall Glaciers, Icy Bay, Alaska. Our results indicate that from 1948 to 1999, the accumulation area of Guyot Glacier above 1220 in elevation lowered at an area-average rate of 0.7 +/- 0.1 m/yr. The accumulation area of Yahtse Glacier, above 1220 in elevation lowered from 1972 to 2000 at an area-average rate of 0.9 +/- 0.1 m/yr. On a same-area basis, Tyndall Glacier lowered from 1972 to 1999 at an area-average rate of 1.4 +/- 0.2 m/yr; then accelerated substantially to 2.8 +/- 0.2 m/yr from 1999 to 2002. From 2000 to 2003 the accumulation area of Yahtse Glacier lowered at 1.5 +/- 0.3 m/yr, on average. The drawdown of these accumulation areas have occurred while snow accumulation at 5000+ m on Mt. Logan, Canada, has shown a strong increase from 1976 to 2000. Concurrently, coastal winter mean temperatures at Cordova and Yakutat, south-central Alaska, have increased to above freezing since about 1979. Retreat and surface lowering of the Icy Bay glaciers is attributed to tidewater glacier dynamics with climate warming effects superimposed. (C) 2007 Elsevier B.V. All rights reserved. C1 [Muskett, Reginald R.] Univ Alaska, Int Arctic Res Ctr, Fairbanks, AK 99701 USA. [Muskett, Reginald R.; Lingle, Craig S.] Univ Alaska, Inst Geophys, Fairbanks, AK 99701 USA. [Sauber, Jeanne A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Rabus, Bernhard T.] MacDonald Dettwiller & Associates, Richmond, BC, Canada. [Tangborn, Wendell V.] Hymet Inc, Washington, DC USA. RP Muskett, RR (reprint author), Univ Alaska, Int Arctic Res Ctr, Fairbanks, AK 99701 USA. EM rmuskett@iarc.uaf.edu RI Sauber, Jeanne/D-7684-2012 NR 51 TC 14 Z9 15 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X EI 1385-013X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD JAN 30 PY 2008 VL 265 IS 3-4 BP 345 EP 359 DI 10.1016/j.epsl.2007.10.012 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 261MH UT WOS:000253082800002 ER PT J AU Jolivet, R Cattin, R Chamotrooke, N Lasserre, C Peltzer, G AF Jolivet, R. Cattin, R. Chamotrooke, Nicolas Lasserre, C. Peltzer, G. TI Thin-plate modeling of interseismic deformation and asymmetry across the Altyn Tagh fault zone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SAN-ANDREAS FAULT; NORTH ANATOLIAN FAULT; STRAIN ACCUMULATION; CALIFORNIA; SYSTEM; FRANCISCO; MARMARA; REGION; CHINA; GANSU AB Creeping dislocations in an elastic half-space are commonly used to model interseismic deformation. However, this semi-infinite conventional model can lead to biased inferences of the slip rate and the fault locking depth. We therefore favor the use of a thin-plate model sheared at its base in agreement with the current knowledge of the seismogenic thickness of the lithosphere. We apply these two approaches to interpret InSAR data across the Altyn Tagh fault system near longitude 94 degrees E, in a region of clear asymmetry of interseismic velocity distribution. Our results suggest a locking depth of 7 - 9 km and a present-day geodetic slip rate of 8 - 10 mm/yr, consistent with the rate based on GPS measurements at this longitude. We interpret the asymmetric pattern as the joint effect of a rigidity decrease from the Tarim basin north of the fault to the Qaidam basin south of it and of a 5 - 7 km southward offset of strain concentration from the quaternary northern active fault. This suggests that the rigidity contrast as well as most of the creep at depth occurs on the southern geological fault. C1 [Jolivet, R.; Cattin, R.; Chamotrooke, Nicolas; Lasserre, C.] CNRS, ENS, Geol Lab, UMR 8538, F-75251 Paris, France. [Peltzer, G.] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. [Peltzer, G.] CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Jolivet, R (reprint author), CNRS, ENS, Geol Lab, UMR 8538, F-75251 Paris, France. EM romain.jolivet@ens.fr RI Cattin, Rodolphe/C-8042-2011; Chamot-Rooke, Nicolas/A-6939-2008; Lasserre, Cecile/D-7073-2017; OI Chamot-Rooke, Nicolas/0000-0001-9924-749X; Lasserre, Cecile/0000-0002-0582-0775; Jolivet, Romain/0000-0002-9896-3651 NR 25 TC 38 Z9 38 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 30 PY 2008 VL 35 IS 2 AR L02309 DI 10.1029/2007GL031511 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 257UI UT WOS:000252823800001 ER PT J AU Zhang, J Poomvises, W Richardson, IG AF Zhang, J. Poomvises, W. Richardson, I. G. TI Sizes and relative geoeffectiveness of interplanetary coronal mass ejections and the preceding shock sheaths during intense storms in 1996-2005 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND; MAGNETIC CLOUDS; SIGNATURES AB We present a statistical study of the sizes of interplanetary coronal mass ejections ( ICMEs) and the preceding shock sheath regions in near- Earth space. The 46 events studied are a subset of the events responsible for intense ( Dst <= - 100 nT) geomagnetic storms in 1996 2005 in which only a single ICME was responsible for generating the storm. We find that the durations and radial sizes of these ICMEs range from 8.0 to 62.0 hr and 0.08 to 0.63 AU, respectively, with average values of 30.6 hr and 0.37 AU. The sheath durations and radial sizes range from 2.6 to 24.5 hr and 0.03 to 0.31 AU, with average values of 10.6 hr and 0.13 AU. On average, the ICME radial size is 2.8 times that of the sheath. In terms of their relative geoeffectiveness, ICMEs contribute on average about 71% of the total energy input ( sheath + ICME) into the magnetosphere. C1 [Zhang, J.; Poomvises, W.] George Mason Univ, Dept Computat & Data Sci, Fairfax, VA 22030 USA. [Richardson, I. G.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Richardson, I. G.] Univ Maryland, Dept Astron, College Pk, MD 20742 USA. [Richardson, I. G.] Univ Maryland, Ctr Res & Explorat Space Sci & Technol, College Pk, MD USA. RP Zhang, J (reprint author), George Mason Univ, Dept Computat & Data Sci, 4400 Univ Dr,MSN 6A2, Fairfax, VA 22030 USA. EM jzhang7@gmu.edu; wpoomvis@gmu.edu; ian.richardson@gsfc.nasa.gov OI Richardson, Ian/0000-0002-3855-3634 NR 17 TC 17 Z9 18 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 30 PY 2008 VL 35 IS 2 AR L02109 DI 10.1029/2007GL032045 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 257UI UT WOS:000252823800003 ER PT J AU Ichii, K White, MA Votava, P Michaelis, A Nemani, RR AF Ichii, Kazuhito White, Michael A. Votava, Petr Michaelis, Andrew Nemani, Rarnakrishna R. TI Evaluation of snow models in terrestrial biosphere models using ground observation and satellite data: impact on terrestrial ecosystem processes SO HYDROLOGICAL PROCESSES LA English DT Article DE water equivalent; snow distribution; remote sensing; water cycle; carbon cycle; terrestrial ecosystem model ID CONTINENTAL UNITED-STATES; INTERCOMPARISON PROJECT; COVER PRODUCTS; 2ND PHASE; LEAF-AREA; MODIS; INDEX; TEMPERATURE; SURFACES; BALANCE AB Snow is important for water management, and an important component of the terrestrial biosphere and climate system. In this study, the snow models included in the Biome-BGC and Terrestrial Observation and Prediction System (TOPS) terrestrial biosphere models are compared against ground and satellite observations over the Columbia River Basin in the US and Canada and the impacts of differences ill snow models oil simulated terrestrial ecosystem processes are analysed. First, a point-based comparison of ground observations against model and satellite estimates of snow dynamics are conducted. Next, model and satellite snow estimates for the entire Columbia River Basin are compared. Then, using two different TOPS simulations, the default TOPS model (TOPS with TOPS snow model) and the TOPS model with the Biome-BGC snow model, the impacts of snow model selection oil runoff and gross primary production (GPP) are investigated. TOPS snow model predictions were consistent with ground and satellite estimates of seasonal and interannual variations in snow cover, snow water equivalent, and snow season length; however, in the Biome-BGC snow model, the snow pack melted too early, leading to extensive Underpredictions of snow season length and snow covered area. These biases led to earlier simulated peak runoff and reductions ill summer GPP, underscoring the need for accurate snow models within terrestrial ecosystem models. Copyright (c) 2007 John Wiley & Sons, Ltd. C1 [Ichii, Kazuhito] San Jose State Univ, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [White, Michael A.; Votava, Petr; Michaelis, Andrew; Nemani, Rarnakrishna R.] NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. [White, Michael A.] Utah State Univ, Dept Aquat Watershed & Earth Resources, Logan, UT 84322 USA. [Votava, Petr; Michaelis, Andrew] Calif State Univ Montery Bay, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ichii, K (reprint author), Fukushima Univ, Fac Symbol Syst Sci, Kanyagawa 1, Fukushima 9601296, Japan. EM kazuhito.ichii@gmail.com RI Ichii, Kazuhito/D-2392-2010; OI Ichii, Kazuhito/0000-0002-8696-8084; White, Michael/0000-0002-0238-8913 NR 31 TC 9 Z9 9 U1 0 U2 6 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0885-6087 J9 HYDROL PROCESS JI Hydrol. Process. PD JAN 30 PY 2008 VL 22 IS 3 BP 347 EP 355 DI 10.1002/hyp.6616 PG 9 WC Water Resources SC Water Resources GA 266ML UT WOS:000253439900004 ER PT J AU Huang, FT Mayr, HG Reber, CA Russell, JM Mlynczak, MG Mengel, JG AF Huang, Frank T. Mayr, Hans G. Reber, Carl A. Russell, James M., III Mlynczak, Martin G. Mengel, John G. TI Ozone quasi-biennial oscillations (QBO), semiannual oscillations (SAO), and correlations with temperature in the mesosphere, lower thermosphere, and stratosphere, based on measurements from SABER on TIMED and MLS on UARS SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID LIMB SOUNDER INSTRUMENT; MIDDLE ATMOSPHERE; WATER-VAPOR; DIURNAL-VARIATIONS; DIMENSIONAL MODEL; VARIABILITY; CHEMISTRY; WAVE AB The ozone and temperature measurements from Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) on the Thermosphere-Ionosphere-Mesosphere- Energetics and Dynamics (TIMED) satellite form a unique set. They provide global information over the range of local solar times, from the lower stratosphere into the lower thermosphere, going back to 2002, by one instrument. On the basis of zonal means of these data, we present new results from 20 to 100 km in altitude and from 48 degrees S to 48 degrees N in latitude of ozone and temperature semiannual oscillations (SAO) and quasi-biennial oscillations (QBO). While some of the results are new for the stratosphere, such results for the mesosphere and lower thermosphere (MLT) have not been available before. The SAO and QBO components are mostly symmetric with respect to the Equator. The correlations of ozone and temperatures provide the opportunity to study the relative effects of dynamics and chemistry. Our results show that the ozone oscillations are largely and positively correlated to those of the temperature below about 30 km and above 80 km, and mostly anti-correlated with temperature between about 30 and 80 km. We compare with measurements made about 10 years earlier by the MLS instrument on UARS, and with results by others from the solar mesosphere explorer (SME) satellite, the solar backscatter ultraviolet (SBUV), space shuttle experiments (CRISTA), and ground-based measurements. C1 [Huang, Frank T.] Creat Comp Solut Inc, Rockville, MD USA. [Mayr, Hans G.] NASA Goddard Space Flight Ctr, Greenbelt, MD USA. [Russell, James M., III] Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. [Reber, Carl A.] Sci & Technol Corp, Hampton, VA 23666 USA. [Mlynczak, Martin G.] NASA, Langley Res Ctr, Hampton, VA USA. [Mengel, John G.] Sci Syst & Appl, Lanham, MD USA. RP Huang, FT (reprint author), Creat Comp Solut Inc, Rockville, MD USA. RI Mlynczak, Martin/K-3396-2012 NR 40 TC 24 Z9 24 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 30 PY 2008 VL 113 IS A1 AR A01316 DI 10.1029/2007JA012634 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258RJ UT WOS:000252886900002 ER PT J AU Canuto, VM Cheng, Y Howard, AM AF Canuto, V. M. Cheng, Y. Howard, A. M. TI A new model for Double Diffusion plus Turbulence SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STABLY STRATIFIED FLOWS; CLOSURE-MODEL; SALT; OCEAN; FLUX; OCEANOGRAPHY; CONVECTION; STAIRCASES; TRANSPORT; MOMENTUM AB Available models of Double Diffusion (DD) processes (Salt Fingers, SF and Diffusive Convection, DC) are primarily based on laboratory experiments that do not include turbulence which is however always present in the ocean. A reliable DD model for use in OGCMs (ocean global circulation models) is therefore still lacking and a true assessment of the role of oceanic DD is yet to be made. Here, we derive and validate a new model for DD + Turbulence using a second-order closure model which differs significantly from previous ones in that the ratios of the correlation time scales to the dissipation time scales, constant in previous models, now depend on Ri and Rr, the key new feature needed to reproduce both laboratory (no shear) and oceanic (with shear) data. The model can therefore be used in OGCMs. The full mixing model includes mixed layer, internal gravity waves, DD and tides. C1 [Canuto, V. M.; Cheng, Y.; Howard, A. M.] NASA, Goddard Inst Space Studies, New York, NY 10025 USA. [Canuto, V. M.] Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. [Cheng, Y.] Columbia Univ, Ctr Climate Syst Res, New York, NY USA. [Howard, A. M.] MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NR 23 TC 17 Z9 17 U1 0 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 29 PY 2008 VL 35 IS 2 AR L02613 DI 10.1029/2007GL032580 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 257UH UT WOS:000252823700007 ER PT J AU Lorenz, RD Mitchell, KL Kirk, RL Hayes, AG Aharonson, O Zebker, HA Paillou, P Radebaugh, J Lunine, JI Janssen, MA Wall, SD Lopes, RM Stiles, B Ostro, S Mitri, G Stofan, ER AF Lorenz, Ralph D. Mitchell, Karl L. Kirk, Randolph L. Hayes, Alexander G. Aharonson, Oded Zebker, Howard A. Paillou, Phillipe Radebaugh, Jani Lunine, Jonathan I. Janssen, Michael A. Wall, Stephen D. Lopes, Rosaly M. Stiles, Bryan Ostro, Steve Mitri, Giuseppe Stofan, Ellen R. TI Titan's inventory of organic surface materials SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CASSINI RADAR OBSERVATIONS; HUYGENS PROBE; ATMOSPHERE; FEATURES; CLOUDS; CYCLE AB Cassini RADAR observations now permit an initial assessment of the inventory of two classes, presumed to be organic, of Titan surface materials: polar lake liquids and equatorial dune sands. Several hundred lakes or seas have been observed, of which dozens are each estimated to contain more hydrocarbon liquid than the entire known oil and gas reserves on Earth. Dark dunes cover some 20% of Titan's surface, and comprise a volume of material several hundred times larger than Earth's coal reserves. Overall, however, the identified surface inventories (>3 X 10(4) km(3) of liquid, and >2 X 10(5) km(3) of dune sands) are small compared with estimated photochemical production on Titan over the age of the solar system. The sand volume is too large to be accounted for simply by erosion in observed river channels or ejecta from observed impact craters. The lakes are adequate in extent to buffer atmospheric methane against photolysis in the short term, but do not contain enough methane to sustain the atmosphere over geologic time. Unless frequent resupply from the interior buffers this greenhouse gas at exactly the right rate, dramatic climate change on Titan is likely in its past, present and future. C1 [Lorenz, Ralph D.] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. [Mitchell, Karl L.; Hayes, Alexander G.; Aharonson, Oded; Janssen, Michael A.; Lopes, Rosaly M.; Stiles, Bryan; Ostro, Steve; Mitri, Giuseppe] CALTECH, Jet Prop Lab, Pasadena, CA USA. [Kirk, Randolph L.] US Geol Survey, Flagstaff, AZ 86001 USA. [Zebker, Howard A.] Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. [Zebker, Howard A.] Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. [Paillou, Phillipe] Observ Aquitain Sci Univers, Lab Astrophys Bordeaux, Florac, France. [Radebaugh, Jani] Brigham Young Univ, Dept Geol Sci, Provo, UT 84602 USA. [Lunine, Jonathan I.] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. [Stofan, Ellen R.] Proxemy Res, Rectortown, VA USA. RP Lorenz, RD (reprint author), Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. RI Hayes, Alexander/P-2024-2014; Lorenz, Ralph/B-8759-2016; Lopes, Rosaly/D-1608-2016 OI Hayes, Alexander/0000-0001-6397-2630; Lorenz, Ralph/0000-0001-8528-4644; Lopes, Rosaly/0000-0002-7928-3167 NR 32 TC 120 Z9 121 U1 4 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 29 PY 2008 VL 35 IS 2 AR L02206 DI 10.1029/2007GL032118 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 257UH UT WOS:000252823700002 ER PT J AU Miyahara, H Wen, G Cahalan, RF Ohmura, A AF Miyahara, Hiroko Wen, Guoyong Cahalan, Robert F. Ohmura, Atsumu TI Deriving historical total solar irradiance from lunar borehole temperatures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MILLENNIUM AB We study the feasibility of deriving historical TSI (Total Solar Irradiance) from lunar borehole temperatures. As the Moon lacks Earth's dynamic features, lunar borehole temperatures are primarily driven by solar forcing. Using Apollo observed lunar regolith properties, we computed present-day lunar regolith temperature profiles for lunar tropical, mid-latitude, and polar regions for two scenarios of solar forcing reconstructed by Lean (2000) and Wang et al. (2005). Results show that these scenarios can be distinguished by small but potentially detectable differences in temperature, on the order of 0.01 K and larger depending on latitude, within similar to 10 m depth of the Moon's surface. Our results provide a physical basis and guidelines for reconstructing historical TSI from data obtainable in future lunar exploration. C1 [Miyahara, Hiroko] Univ Tokyo, Dept Earth & Planetary Sci, Tokyo, Japan. [Wen, Guoyong] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. [Cahalan, Robert F.] NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. [Ohmura, Atsumu] Swiss Fed Inst Technol, Inst Atmospher & Climate Sci, Zurich, Switzerland. RP Miyahara, H (reprint author), Univ Tokyo, Dept Earth & Planetary Sci, Tokyo, Japan. RI Cahalan, Robert/E-3462-2012 OI Cahalan, Robert/0000-0001-9724-1270 NR 15 TC 0 Z9 1 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 29 PY 2008 VL 35 IS 2 AR L02716 DI 10.1029/2007GL032171 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 257UH UT WOS:000252823700003 ER PT J AU Milner-White, EJ Russell, MJ AF Milner-White, E. James Russell, Michael J. TI Predicting the conformations of peptides and proteins in early evolution. A review article submitted to Biology Direct SO BIOLOGY DIRECT LA English DT Review ID ANION-BINDING MOTIFS; CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; ALPHA-SHEET; POTASSIUM CHANNEL; UNFOLDED PROTEINS; CARBONYL SULFIDE; SULFUR-COMPOUNDS; AQUEOUS-MEDIA; AMINO-ACIDS AB Considering that short, mainly heterochiral, polypeptides with a high glycine content are expected to have played a prominent role in evolution at the earliest stage of life before nucleic acids were available, we review recent knowledge about polypeptide three- dimensional structure to predict the types of conformations they would have adopted. The possible existence of such structures at this time leads to a consideration of their functional significance, and the consequences for the course of evolution. C1 [Milner-White, E. James] Univ Glasgow, Inst Biomed & Life Sci, Glasgow G12 8QQ, Lanark, Scotland. [Russell, Michael J.] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Milner-White, EJ (reprint author), Univ Glasgow, Inst Biomed & Life Sci, Glasgow G12 8QQ, Lanark, Scotland. EM Milner-White@bio.gla.ac.uk; Michael.J.Russell@jpl.nasa.gov NR 74 TC 25 Z9 26 U1 0 U2 12 PU BIOMED CENTRAL LTD PI LONDON PA 236 GRAYS INN RD, FLOOR 6, LONDON WC1X 8HL, ENGLAND SN 1745-6150 J9 BIOL DIRECT JI Biol. Direct PD JAN 28 PY 2008 VL 3 AR 3 DI 10.1186/1745-6150-3-3 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 274QT UT WOS:000254016600001 PM 18226248 ER PT J AU Horton, R Herweijer, C Rosenzweig, C Liu, JP Gornitz, V Ruane, AC AF Horton, Radley Herweijer, Celine Rosenzweig, Cynthia Liu, Jiping Gornitz, Vivien Ruane, Alex C. TI Sea level rise projections for current generation CGCMs based on the semi-empirical method SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLIMATE-CHANGE; ICE SHEETS; RECORD; GASES AB The semi-empirical relationship between global surface air temperature and mean sea level first developed by Rahmstorf is here applied to the latest generation of Coupled Global Climate Models (CGCMs) used for the IPCC Fourth Assessment Report (AR4). Our results produce a broader range of sea level rise projections, especially at the higher end, than outlined in IPCC AR4. The range of sea level rise results is CGCM and emissions-scenario dependent, and not sensitive to initial conditions or how the data are filtered temporally. Both the IPCC AR4 and the semi-empirical sea level rise projections described here are likely to underestimate future sea level rise if recent trends in the polar regions accelerate. C1 [Horton, Radley; Gornitz, Vivien] Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. [Herweijer, Celine] Risk Management Solut, London EC3R 8NB, England. [Liu, Jiping] Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. [Rosenzweig, Cynthia; Ruane, Alex C.] NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Horton, R (reprint author), Columbia Univ, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. EM radley.m.horton@gmail.com RI LIU, JIPING/N-6696-2016 NR 17 TC 84 Z9 86 U1 0 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 26 PY 2008 VL 35 IS 2 AR L02715 DI 10.1029/2007GL032486 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 256TD UT WOS:000252751900005 ER PT J AU Nightingale, JM Hill, MT Phinn, SR Davies, ID Held, AA Erskine, PD AF Nightingale, J. M. Hill, M. T. Phinn, S. R. Davies, I. D. Held, A. A. Erskine, P. D. TI Use of 3-PG and 3-PGS to simulate forest growth dynamics of Australian tropical rainforests - I. Parameterisation and calibration for old-growth, regenerating and plantation forests SO FOREST ECOLOGY AND MANAGEMENT LA English DT Article DE North Queensland tropical rainforest; Australia; ecosystem models; forest growth and productivity modelling ID NET PRIMARY PRODUCTION; NORTH QUEENSLAND; PROCESS MODEL; NEW-ZEALAND; SENSITIVITY-ANALYSIS; EUCALYPTUS-GLOBULUS; PRODUCTIVITY MODEL; BRAZILIAN AMAZON; FUTURE CLIMATES; BIOMASS AB Accurate information concerning regional to ecosystem-scale carbon dynamics within tropical rainforests is important because of the increasing certainty that the global climate will change significantly within the next century. Tropical forests of north Queensland, Australia, are highly sensitive to climate change and substantial shifts in the distribution of these forests are likely to occur with minor variations in climate. The focus of this research was the development of a model-based system for assessing forest growth and biomass accumulation dynamics within Australia's tropical rainforest bioregion and predicting the impacts of climate change on these dynamics. This paper presents the parameterisation and calibration of (a) the 3-PG (Physiological Principles Predicting Growth) model to a selection of restored rainforest and commercial timber plantations and (b) a modified version 3-PGS which uses satellite data, enabling the spatial assessment of mature tropical rainforest growth and production throughout the wet tropics bioregion. Statistically significant relationships were observed between 3-PG and 3-PGS modelled and field measured estimates of stand structural attributes including, basal area (BA), diameter at breast height (DBH) and above-ground biomass (AGB) throughout the bioregion. 3-PG and 3-PGS modelled leaf area index (LAI) and net primary production (NPP) related well to published estimates at other similar rainforest sites. These results indicate that the simple, process-based models are effective at capturing the growth dynamics of structurally complex old-growth, restoration and plantation rainforests. (c) 2007 Elsevier B.V. All rights reserved. C1 [Nightingale, J. M.; Phinn, S. R.] Univ Queensland, Sch Geog Planning & Architecture, Ctr Remote Sensing & Spatial Informat Sci, Brisbane, Qld 4072, Australia. [Hill, M. T.] Univ N Dakota, Dept Earth Syst Sci & Policy, Grand Forks, ND 58202 USA. [Davies, I. D.] Australian Natl Univ, Res Sch Biol Sci, Ecosyst Dynam Grp, Canberra, ACT 2601, Australia. [Held, A. A.] CSIRO, Off Space Sci & Applicat, Canberra, ACT 2061, Australia. [Erskine, P. D.] Univ Queensland, Sch Bot, Brisbane, Qld 4072, Australia. [Nightingale, J. M.; Hill, M. T.; Davies, I. D.] Australian Natl Univ, Cooperat Res Ctr Greenhouse Accounting, Canberra, ACT 2061, Australia. [Nightingale, J. M.; Phinn, S. R.] Univ Queensland, Sch Geog Planning & Architecture, Biophys Remote Sensing Grp, Brisbane, Qld 4072, Australia. RP Nightingale, JM (reprint author), NASA, Goddard Space Flight Ctr, Terr Informat Syst Branch, Code 614-5,Bld 33, Greenbelt, MD 20771 USA. EM jnight@ltpmail.gsfc.nasa.gov RI Minerals Institute, Sustainable/F-8043-2010; Held, Andre/A-4672-2011; OI Hill, Michael/0000-0003-4570-7467; Phinn, Stuart/0000-0002-2605-6104 NR 71 TC 20 Z9 20 U1 1 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1127 J9 FOREST ECOL MANAG JI For. Ecol. Manage. PD JAN 25 PY 2008 VL 254 IS 2 BP 107 EP 121 DI 10.1016/j.foreco.2007.03.041 PG 15 WC Forestry SC Forestry GA 256XL UT WOS:000252763100001 ER PT J AU Richardson, IG Zhang, J AF Richardson, I. G. Zhang, J. TI Multiple-step geomagnetic storms and their interplanetary drivers SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND AB While the classic picture of a geomagnetic storm is of a main phase eventually reaching maximum intensity, followed by a recovery, the profile can often be more complex. This has been recognized in past studies that have classified storms as having "one'' or "two'' "steps'' during the main phase. However, the intense ( Dst <= -100 nT) storms studied during the LWS CDAW Workshop may be more complicated. We discuss the variety of interplanetary circumstances that gave rise to several storms of varying complexity. C1 NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. [Zhang, J.] George Mason Univ, Dept Computat & Data Sci, Fairfax, VA 22030 USA. RP Richardson, IG (reprint author), NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Code 661, Greenbelt, MD 20771 USA. EM ian.richardson@gsfc.nasa.gov; jzhang7@gmu.edu OI Richardson, Ian/0000-0002-3855-3634 NR 7 TC 12 Z9 13 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 25 PY 2008 VL 35 IS 6 AR L06S07 DI 10.1029/2007GL032025 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 256TF UT WOS:000252752100002 ER PT J AU Slavin, JA Le, G Strangeway, RJ Wang, Y Boardsen, SA Moldwin, MB Spence, HE AF Slavin, J. A. Le, G. Strangeway, R. J. Wang, Y. Boardsen, S. A. Moldwin, M. B. Spence, H. E. TI Space technology 5 multi-point measurements of near-Earth magnetic fields: Initial results SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ALIGNED CURRENTS AB The Space Technology 5 (ST-5) mission successfully placed three micro-satellites in a 300 x 4500 km dawn-dusk orbit on 22 March 2006. Each spacecraft carried a boom-mounted vector fluxgate magnetometer that returned highly sensitive and accurate measurements of the geomagnetic field. These data allow, for the first time, the separation of temporal and spatial variations in field-aligned current (FAC) perturbations measured in low-Earth orbit on time scales of similar to 10 sec to 10 min. The constellation measurements are used to directly determine field-aligned current sheet motion, thickness, and current density. In doing so, we demonstrate two multi-point methods for the inference of FAC current density that have not previously been possible in low-Earth orbit: 1) the "standard method,'' based upon s/c velocity, but corrected for FAC current sheet motion, and 2) the "gradiometer method'' which uses simultaneous magnetic field measurements at two points with known separation. Future studies will apply these methods to the entire ST-5 data set and expand to include geomagnetic field gradient analyses as well as field-aligned and ionospheric currents. C1 [Slavin, J. A.; Le, G.; Wang, Y.; Boardsen, S. A.] NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. [Strangeway, R. J.; Moldwin, M. B.] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. [Spence, H. E.] Boston Univ, Dept Astron, Boston, MA 02215 USA. [Spence, H. E.] Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. RP Slavin, JA (reprint author), NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. EM james.a.slavin@nasa.gov RI Moldwin, Mark/F-8785-2011; Le, Guan/C-9524-2012; Slavin, James/H-3170-2012; Spence, Harlan/A-1942-2011; OI Moldwin, Mark/0000-0003-0954-1770; Le, Guan/0000-0002-9504-5214; Slavin, James/0000-0002-9206-724X; Spence, Harlan/0000-0002-2526-2205 NR 13 TC 27 Z9 27 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 25 PY 2008 VL 35 IS 2 AR L02107 DI 10.1029/2007GL031728 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 256TC UT WOS:000252751800002 ER PT J AU Lee, MI Schubert, SD Suarez, MJ Schemm, JKE Pan, HL Han, J Yoo, SH AF Lee, Myong-In Schubert, Siegfried D. Suarez, Max J. Schemm, Jae-Kyung E. Pan, Hua-Lu Han, Jongil Yoo, Soo-Hyun TI Role of convection triggers in the simulation of the diurnal cycle of precipitation over the United States Great Plains in a general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LOW-LEVEL JET; MOISTURE TRANSPORT; PARAMETERIZATION; COMPLEXES; ENSEMBLE; SYSTEMS AB Recent comparisons of a number of general circulation models (GCMs) have shown that most of them have deficiencies in the simulation of the diurnal cycle of warm season precipitation. The deficiencies are particularly pronounced over the United States Great Plains where the models generally fail to capture the nocturnal rainfall maximum found in the observations. By using the National Centers for Environmental Prediction's Global Forecasting System (NCEP GFS) GCM, which is unusual in that it produces a realistic nocturnal rainfall signal over the Great Plains, this study examines the nature and realism of the mechanisms responsible for the nocturnal rain in the GCM. A series of sensitivity experiments highlight the importance of triggers implemented in the convection scheme. Specifically, the convection trigger function that the cloud base ( defined as the level of free convection) must be within 150 hPa depth from the convection starting level ( which crudely represents an upper limit of convective inhibition) plays a key role on the realistic simulation of the diurnal phase of convection. On the basis of this trigger, the nighttime elevation of the convection starting level ( defined as the maximum level of moist static energy from the surface) above the boundary layer inversion provides the condition favorable for the development of nocturnal precipitation over the Great Plains. The results are discussed in terms of their implications for improving our understanding and parameterizations of the physical processes that generate nocturnal rain in this and other regions with large diurnal cycles. C1 [Lee, Myong-In] Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. [Lee, Myong-In; Schubert, Siegfried D.; Suarez, Max J.] NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. [Schemm, Jae-Kyung E.; Pan, Hua-Lu; Han, Jongil; Yoo, Soo-Hyun] NOAA, Natl Ctr Environm Predict, Camp Springs, MD USA. [Han, Jongil; Yoo, Soo-Hyun] RS Informat Syst Inc, Mclean, VA USA. RP Lee, MI (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. EM myong-in.lee@nasa.gov OI Lee, Myong-In/0000-0001-8983-8624 NR 30 TC 29 Z9 29 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 25 PY 2008 VL 113 IS D2 AR D02111 DI 10.1029/2007JD008984 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 256TM UT WOS:000252752800002 ER PT J AU Unger, N Shindell, DT Koch, DM Streets, DG AF Unger, Nadine Shindell, Drew T. Koch, Dorothy M. Streets, David G. TI Air pollution radiative forcing from specific emissions sectors at 2030 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPOSPHERIC OZONE; CLIMATE AGREEMENTS; REGIONAL EMISSIONS; AEROSOL EMISSIONS; GISS MODELE; SIMULATIONS; METHANE; PREINDUSTRIAL; SENSITIVITY; PRECURSORS AB Reduction of short-lived air pollutants can contribute to mitigate global warming in the near-term with ancillary benefits to human health. However, the radiative forcings of short-lived air pollutants depend on the location and source type of the precursor emissions. We apply the Goddard Institute for Space Studies atmospheric composition-climate model to quantify near-future (2030 A1B) global annual mean radiative forcing by ozone (O-3) and sulfate from six emissions sectors in seven geographic regions. At 2030 the net forcings from O3, sulfate, black and organic carbon, and indirect CH4 effects for each emission sector are (in mWm(-2)) biomass burning, +95; domestic, +68; transportation, +67; industry, -131; and power, -224. Biomass burning emissions in East Asia and central and southern Africa, domestic biofuel emissions in East Asia, south Asia, and central and southern Africa, and transportation emissions in Europe and North America have large net positive forcings and are therefore attractive targets to counter global warming. Power and industry emissions from East Asia, south Asia, and north Africa and the Middle East have large net negative forcings. Therefore air quality control measures that affect these regional sectors require offsetting climate measures to avoid a warming impact. Linear relationships exist between O3 forcing and biomass burning and domestic biofuel CO precursor emissions independent of region with sensitivity of +0.2 mWm(-2)/TgCO. Similarly, linear relationships exist between sulfate forcing and SO2 precursor emissions that depend upon region but are independent of sector with sensitivities ranging from -3 to -12 mWm(-2)/TgS. C1 [Unger, Nadine; Shindell, Drew T.; Koch, Dorothy M.] Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. [Streets, David G.] Argonne Natl Lab, Argonne, IL 60439 USA. RP Unger, N (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. EM nunger@giss.nasa.gov RI Shindell, Drew/D-4636-2012; Unger, Nadine/M-9360-2015; OI Streets, David/0000-0002-0223-1350 NR 46 TC 33 Z9 33 U1 1 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 25 PY 2008 VL 113 IS D2 AR D02306 DI 10.1029/2007JD008683 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 256TM UT WOS:000252752800001 ER PT J AU Ebihara, Y Nishitani, N Kikuchi, T Ogawa, T Hosokawa, K Fok, MC AF Ebihara, Y. Nishitani, N. Kikuchi, T. Ogawa, T. Hosokawa, K. Fok, M. -C. TI Two-dimensional observations of overshielding during a magnetic storm by the Super Dual Auroral Radar Network (SuperDARN) Hokkaido radar SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EQUATORIAL ELECTRIC-FIELDS; MAGNETOSPHERIC CONVECTION; DISTURBED CONDITIONS; GRAVITY-WAVES; LOW LATITUDES; RING CURRENT; MODEL; IONOSPHERE; PLASMA; CONDUCTIVITY AB [1] Two-dimensional observations of ionospheric plasma flows possibly caused by overshielding are reported for the first time. The observations were made by the midlatitude Super Dual Auroral Radar Network Hokkaido radar in Japan during a major magnetic storm on 15 December 2006. The magnetosphere was exposed continuously to a southward interplanetary magnetic field (IMF) for several hours during the main phase of the storm. Immediately following the subsequent northward turning of the IMF, an antisunward plasma flow was observed for about 14 min in the predusk sector at magnetic latitudes of 50 degrees-60 degrees, reaching a maximum line-of-sight speed of 70-80 m/s. These features are consistent with a simulation of coupling between the ring current and the ionosphere associated with an overshielding condition. Within 1 h of the first observation, a similar antisunward flow was observed during a period of southward oriented IMF. However, the simulation cannot account for the antisunward flow in this case. It is suggested that the shielding/overshielding condition is not simply caused by the northward turning of IMF. This second overshielding-like condition is attributable to a sudden contraction of the polar cap associated with the substorm or to a sudden strengthening of the inertial current converted from the abrupt injection of magnetospheric ions. However, neither fully accounts for the observations. C1 [Ebihara, Y.] Nagoya Univ, Inst Adv Res, Chikusa Ku, Nagoya, Aichi 4648601, Japan. [Fok, M. -C.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Nishitani, N.; Kikuchi, T.] Nagoya Univ, Solar Terr Environm Lab, Chikusa Ku, Nagoya, Aichi 4648601, Japan. [Ogawa, T.] Nagoya Univ, Solar Terr Environm Lab, Aichi 4428507, Japan. [Hosokawa, K.] Univ Electrocommun, Dept Informat & Commun Engn, Chofu, Tokyo 1828585, Japan. RP Ebihara, Y (reprint author), Nagoya Univ, Inst Adv Res, Chikusa Ku, Furo Cho, Nagoya, Aichi 4648601, Japan. EM ebihara@stelab.nagoya-u.ac.jp; nisitani@stelab.nagoya-u.ac.jp; kikuchi@stelab.nagoya-u.ac.jb; ogawa@stelab.nagoya-u.ac.jp; hosokawa@ice.uec.ac.jp; mei-ching.fok@gsfc.nasa.gov RI Fok, Mei-Ching/D-1626-2012; Ebihara, Yusuke/D-1638-2013 OI Ebihara, Yusuke/0000-0002-2293-1557 NR 39 TC 24 Z9 25 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 25 PY 2008 VL 113 IS A1 AR A01213 DI 10.1029/2007JA012641 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256UG UT WOS:000252754800002 ER PT J AU Su, CH Lehoczky, SL Raghothamachar, B Dudley, M AF Su, Ching-Hua Lehoczky, S. L. Raghothamachar, B. Dudley, M. TI Crystal growth and characterization of CdTe grown by vertical gradient freeze SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article DE cadmium telluride (CdTe); vertical gradient freeze; semiconductors ID BRIDGMAN GROWTH; LOW-TEMPERATURE; BULK CDTE; DEFECTS; MELT; QUALITY; ZINC; PHOTOLUMINESCENCE; CD1-XZNXTE; BEHAVIOR AB In this study, crystals of CdTe were grown from melts by the unseeded vertical gradient freeze method. The thermal history of the melt and the thermal gradient at the growth interface were adjusted to optimize the crystalline quality of the grown crystals. The grown crystals were studied by various characterization techniques, including synchrotron white beam X-ray topography (SWBXT), chemical analysis by glow discharge mass spectroscopy (GDMS), low temperature photoluminescence (PL) and Hall measurements. The SWBXT images taken from various angles show grains with inhomogeneous strains, nearly strain-free grains, as well as twinning nucleated in the shoulder region of the boule. The GDMS chemical analysis shows the contamination of Ga at a level of 3900 ppb, atomic. The low temperature PL measurement exhibits the characteristic emissions of a Ga-doped sample. The Hall measurements show a resistivity of 1 X 10(7) Omega cm at room temperature and 3 x 10(9) Omega cm at 78 K with the respective hole and electron concentration of 1.7 x 10(9) and 3.9 x 10(7) cm(-3) at room temperature. (c) 2007 Elsevier B.V. All rights reserved. C1 [Su, Ching-Hua; Lehoczky, S. L.] NASA, George C Marshall Space Flight Ctr, Engn Directorate, Mat & Proc Lab, Huntsville, AL 35812 USA. [Raghothamachar, B.; Dudley, M.] SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Su, CH (reprint author), NASA, George C Marshall Space Flight Ctr, Engn Directorate, Mat & Proc Lab, EM30, Huntsville, AL 35812 USA. EM ching.h.su@nasa.gov RI Raghothamachar, Balaji/B-1094-2008 NR 44 TC 6 Z9 7 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD JAN 25 PY 2008 VL 147 IS 1 BP 35 EP 42 DI 10.1016/j.mseb.2007.11.005 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 269QS UT WOS:000253664600006 ER PT J AU Qu, TD Gao, S Fukumori, I Fine, RA Lindstrom, EJ AF Qu, Tangdong Gao, Shan Fukumori, Ichiro Fine, Rana A. Lindstrom, Eric J. TI Subduction of South Pacific waters SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTIC INTERMEDIATE WATER; NORTH-PACIFIC; MODE WATERS; OCEAN; CIRCULATION; ORIGIN; VENTILATION; GCM AB Using existing high-resolution CTD observations, complemented by a large amount of recently available Argo floating data, this study provides a detailed description of the subduction of South Pacific waters. With a significantly improved climatological dataset on the mixed layer properties, we obtain an annual subduction rate of 48.8 Sv (1 Sv = 10(6) m(3) s(-1)) from 10 degrees S to 60 degrees S in the South Pacific. Two peaks stand out in this subduction rate sorted by winter mixed layer density: one corresponds to the formation of eastern Subtropical Mode Water (STMW) and part of the Subtropical Underwater (SUW) between 25.0 and 25.5 sigma(theta), and the other has a density range between 26.6 and 27.1 sigma(theta), representing the formation of Sub-Antarctic Mode Water and Antarctic Intermediate Water (SAMW/AAIW). The subduction in eastern STMW/SUW range is 12.7 Sv, only slightly smaller than that (14.6 Sv) associated with the SAMW/AAIW. Sandwiched between these two peaks, roughly in the density range between 26.0 and 26.5 sigma(theta), is the southwestern STMW, with a relatively small annual subduction of 5.6 Sv. Uncertainties of these estimates are discussed. C1 [Qu, Tangdong; Gao, Shan] Univ Hawaii Manoa, Int Pacific Res Ctr, SOEST, Honolulu, HI 96822 USA. [Fukumori, Ichiro] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Fine, Rana A.] Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. [Lindstrom, Eric J.] NASA, Sci Mission Directorate, Washington, DC 20546 USA. RP Qu, TD (reprint author), Univ Hawaii Manoa, Int Pacific Res Ctr, SOEST, 1680 East West Rd, Honolulu, HI 96822 USA. EM tangdong@hawaii.edu RI Gao, Shan/H-7959-2013 OI Gao, Shan/0000-0003-4510-5028 NR 25 TC 19 Z9 19 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 24 PY 2008 VL 35 IS 2 AR L02610 DI 10.1029/2007GL032605 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 256TB UT WOS:000252751700008 ER PT J AU Noel, V Hertzog, A Chepfer, H Winker, DM AF Noel, Vincent Hertzog, Albert Chepfer, Helene Winker, David M. TI Polar stratospheric clouds over Antarctica from the CALIPSO spaceborne lidar SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PARTICLE COMPOSITION; ARCTIC STRATOSPHERE; SOLVE/THESEO 2000; DUMONT DURVILLE; GRAVITY-WAVES; LONG-TERM; CLIMATOLOGY; AEROSOL; OZONE; TEMPERATURES AB This paper presents statistics of polar stratospheric clouds (PSCs) above Antarctica from June to October 2006 using observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) spaceborne lidar, part of the CALIPSO mission. Synoptic-scale changes in geographic and temporal distribution are documented weekly and correlated with temperature fields. A high spatial and temporal variability tends to contradict the hypothesis that PSCs are mostly created via slow processes mainly governed by large-scale temperature changes. Linear depolarization ratios reveal strongly typed PSCs with distinct characteristics (implying different microphysics), but unique cloud compositions cannot be singled out. A west/east imbalance is observed in the depolarization distribution, symptomatic of microphysical disparities. A classification based on depolarization and scattering ratios suggests more than 60% of mixed PSCs, followed by more than 20% of STS, and a roughly equal concentration of nitric acid trihydrate (NAT)-based and pure ice PSCs (similar to 8%). Up to the beginning of August, supercooled ternary solution (STS) PSCs experience a steady decrease in concentration correlated with an increase in ice-based and mixed PSCs; this tendency gets reversed after the first week of August, hinting at the existence of a large-scale seasonal cycle in PSC population. C1 [Noel, Vincent] Ecole Polytech, CNRS, Meteorol Dynam Lab, Inst Pierre Simon Laplace, F-91128 Palaiseau, France. [Hertzog, Albert; Chepfer, Helene] Univ Paris 06, Meteorol Dynam Lab, Inst Pierre Simon Laplace, Palaiseau, France. [Winker, David M.] NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Noel, V (reprint author), Ecole Polytech, CNRS, Meteorol Dynam Lab, Inst Pierre Simon Laplace, F-91128 Palaiseau, France. EM vincent.noel@lmd.polytechnique.fr RI Hertzog, Albert/A-2899-2012; Noel, Vincent/C-3702-2013 OI Noel, Vincent/0000-0001-9494-0340 NR 51 TC 30 Z9 30 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 24 PY 2008 VL 113 IS D2 AR D02205 DI 10.1029/2007JD008616 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 256TK UT WOS:000252752600002 ER PT J AU Holzer, M Primeau, FW AF Holzer, Mark Primeau, Francois W. TI The path-density distribution of oceanic surface-to-surface transport SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID THERMOHALINE CIRCULATION; NORTH-ATLANTIC; ABYSSAL OCEAN; CONVEYOR BELT; VENTILATION; MODEL; TRACERS; LAYER; TIME; AGE AB [1] A novel diagnostic for advective-diffusive surface-to-surface paths is developed and applied to a global ocean model. The diagnostic provides, for the first time, a rigorous quantitative assessment of the great ocean conveyor's deep branch. A new picture emerges of a diffusive conveyor in which the deep North Pacific is a holding pen of long-residence-time water. Our diagnostic is the joint density, h, per unit volume and interior residence time, tau, of paths connecting two specified surface patches. The spatially integrated eta determines the residence-time partitioned flux and volume of water in transit from entry to exit patch. We focus on interbasin paths from high-latitude water mass formation regions to key regions of re-exposure to the atmosphere. For non-overlapping patches, a characteristic timescale is provided by the residence time, tau(phi), for which the associated flux distribution, phi, has its maximum. Paths that are fast compared to tau(phi) are organized by the major current systems, while paths that are slow compared to tau(phi) are dominated by eddy diffusion. Because phi has substantial weight in its tail for tau > tau(phi), the fast paths account for only a minority of the formation-to-re-exposure flux. This conclusion is expected to apply to the real ocean based on recent tracer data analyses, which point to long eddy-diffusive tails in the ocean's transit-time distributions. The long-tau asymptotic path density is governed by two time-invariant patterns. One pattern, which we call the Deep North Pacific pattern, ultimately dominates a secondary redistribution pattern. C1 [Holzer, Mark] Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. [Holzer, Mark] NASA, Goddard Inst Space Studies, New York, NY 10025 USA. [Holzer, Mark] Univ British Columbia, Dept Earth & Ocean Sci, Vancouver, BC V5Z 1M9, Canada. [Holzer, Mark] Langara Coll, Dept Phys, Vancouver, BC, Canada. [Primeau, Francois W.] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. RP Holzer, M (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM hm2220@columbia.edu; fprimeau@uci.edu RI Primeau, Francois /A-7310-2011 OI Primeau, Francois /0000-0001-7452-9415 NR 36 TC 16 Z9 16 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JAN 24 PY 2008 VL 113 IS C1 AR C01018 DI 10.1029/2006JC003976 PG 22 WC Oceanography SC Oceanography GA 256TT UT WOS:000252753500001 ER PT J AU Zong, QG Zhang, H Fritz, TA Goldstein, ML Wing, S Keith, W Winningham, JD Frahm, R Dunlop, MW Korth, A Daly, PW Reme, H Balogh, A Fazakerley, AN AF Zong, Q. -G. Zhang, H. Fritz, T. A. Goldstein, M. L. Wing, S. Keith, W. Winningham, J. D. Frahm, R. Dunlop, M. W. Korth, A. Daly, P. W. Reme, H. Balogh, A. Fazakerley, A. N. TI Multiple cusps during an extended northward IMF period with a significant B-y component SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-ALTITUDE CUSP; INTERPLANETARY MAGNETIC-FIELD; SOLAR-WIND CONTROL; MAGNETOTAIL GEOTAIL OBSERVATIONS; HIGH-LATITUDE MAGNETOPAUSE; KELVIN-HELMHOLTZ VORTICES; NEAR-EARTH MAGNETOTAIL; CLUSTER OBSERVATIONS; BOUNDARY-LAYER; EXTERIOR CUSP AB On 21-22 March 2001, four cusp-like regions were observed consecutively in about five hours by all four Cluster spacecraft when the interplanetary magnetic field (IMF) was northward with a significant By component. All four cusp-like encounters were characterized by turbulent magnetic fields, high-density plasma, and plasma flow significantly slower than the magnetosheath level. The cusp-like regions are associated with thermalized, bidirectional distributed plasma electrons. The first encountered cusp is the main cusp; the other three cusp-like regions are temporal effects. The normal velocities v(n) at boundary interfaces (exit from the cusp) are found to be almost three times larger than that at boundary interfaces (entry into the cusp). The boundary normal, velocity, and timing analysis for six clear boundaries of the last three cusps obtained by all four spacecraft indicates that they are most likely one boundary shifting in the dawn-dusk direction between the dayside magnetosphere/trapping region and the cusp region. So the Cluster spacecraft have been observing the same cusp, and it appeared as four cusp-like regions due to possible magnetospheric oscillations. Oscillations with a period of 22 min are observed by the Cluster spacecraft in the high-latitude region, which is in agreement with the cold-dense plasma sheet fluctuations (20 min period) observed by the Geotail satellite. Multiple cusps observed by Cluster and the wavy-like structures in the dusk low-latitude boundary layer observed by Geotail simultaneously suggest the whole magnetosphere is oscillating during northward IMF. C1 [Zong, Q. -G.] Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 02215 USA. [Zong, Q. -G.] Chinese Acad Sci, State Key Lab Space Weather, Beijing, Peoples R China. [Zhang, H.; Fritz, T. A.] Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. [Goldstein, M. L.; Keith, W.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Wing, S.] Johns Hopkins Univ, Appl Phys Lab, Baltimore, MD 21218 USA. [Frahm, R.] SW Res Inst, San Antonio, TX 78228 USA. [Dunlop, M. W.] Rutherford Appleton Lab, Oxford 0X11 0QX, England. [Korth, A.; Daly, P. W.] Max Planck Inst Sonnersystemfunsong, D-37191 Katlenburg Lindau, Germany. [Reme, H.] Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. [Balogh, A.] Univ London Imperial Coll Sci Technol & Med, Space Atmospher Phys Grp, London SW7 2BZ, England. [Fazakerley, A. N.] Mullard Space Sci Lab, Surrey RH5 6NT, England. RP Zong, QG (reprint author), Univ Massachusetts, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 02215 USA. EM zong@bu.edu RI dunlop, malcolm/F-1347-2010; Goldstein, Melvyn/B-1724-2008 NR 52 TC 9 Z9 9 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 24 PY 2008 VL 113 IS A1 AR A01210 DI 10.1029/2006JA012188 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256UE UT WOS:000252754600001 ER PT J AU Sanchez-Lavega, A Orton, GS Hueso, R Garcia-Melendo, E Perez-Hoyos, S Simon-Miller, A Rojas, JF Gomez, JM Yanamandra-Fisher, P Fletcher, L Joels, J Kemerer, J Hora, J Karkoschka, E de Pater, I Wong, MH Marcus, PS Pinilla-Alonso, N Carvalho, F Go, C Parker, D Salway, M Valimberti, M Wesley, A Pujic, Z AF Sanchez-Lavega, A. Orton, G. S. Hueso, R. Garcia-Melendo, E. Perez-Hoyos, S. Simon-Miller, A. Rojas, J. F. Gomez, J. M. Yanamandra-Fisher, P. Fletcher, L. Joels, J. Kemerer, J. Hora, J. Karkoschka, E. de Pater, I. Wong, M. H. Marcus, P. S. Pinilla-Alonso, N. Carvalho, F. Go, C. Parker, D. Salway, M. Valimberti, M. Wesley, A. Pujic, Z. TI Depth of a strong jovian jet from a planetary-scale disturbance driven by storms SO NATURE LA English DT Article ID DEEP ZONAL WINDS; MOIST CONVECTION; NONLINEAR SIMULATIONS; 3-DIMENSIONAL MODEL; JUPITERS ATMOSPHERE; GIANT PLANETS; STABILITY; DYNAMICS; CASSINI; GALILEO AB The atmospheres of the gas giant planets ( Jupiter and Saturn) contain jets that dominate the circulation at visible levels(1,2). The power source for these jets ( solar radiation, internal heat, or both) and their vertical structure below the upper cloud are major open questions in the atmospheric circulation and meteorology of giant planets(1-3). Several observations(1) and in situ measurements(4) found intense winds at a depth of 24 bar, and have been interpreted as supporting an internal heat source. This issue remains controversial(5), in part because of effects from the local meteorology(6). Here we report observations and modelling of two plumes in Jupiter's atmosphere that erupted at the same latitude as the strongest jet ( 23 degrees N). The plumes reached a height of 30 km above the surrounding clouds, moved faster than any other feature ( 169 m s(-1)), and left in their wake a turbulent planetary- scale disturbance containing red aerosols. On the basis of dynamical modelling, we conclude that the data are consistent only with a wind that extends well below the level where solar radiation is deposited. C1 [Sanchez-Lavega, A.; Hueso, R.; Perez-Hoyos, S.] Univ Basque Country, ETS Ingenieros, Dept Fis Aplicada 1, Bilbao 48013, Spain. [Orton, G. S.; Yanamandra-Fisher, P.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Garcia-Melendo, E.; Gomez, J. M.] Esteve Duran Observ Fdn, Seva 085330, Spain. [Simon-Miller, A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Rojas, J. F.] Univ Basque Country, EUITI, Dept Fis Aplicada 1, Bilbao 48013, Spain. [Fletcher, L.] Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. [Joels, J.] Principia Coll, Elsah, IL 62028 USA. [Kemerer, J.] Calif State Polytech Univ Pomona, Pomona, CA 91768 USA. [Hora, J.] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. [Karkoschka, E.] Univ Arizona, Tucson, AZ 85721 USA. [de Pater, I.; Wong, M. H.] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. [Marcus, P. S.] Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. [Pinilla-Alonso, N.] Telescopio Nazl Galileo Galilei, Santa Cruz De La Palma 38700, Spain. [Carvalho, F.] Ctr Estudos Universo, BR-17380000 Brotas, Brazil. [Go, C.] Univ San Carlos, Dept Phys, Cebu 6000, Philippines. [Parker, D.] Assoc Lunar & Planetary Observers, Coral Gables, FL 33156 USA. [Salway, M.] IcelnSpace, Wyoming, NSW 2250, Australia. [Valimberti, M.] Astron Soc Victoria, Melbourne, Vic 3001, Australia. [Wesley, A.] Math & Comp Sci, Murrumbateman 2582, Australia. RP Sanchez-Lavega, A (reprint author), Univ Basque Country, ETS Ingenieros, Dept Fis Aplicada 1, Alameda Urquijo S-N, Bilbao 48013, Spain. EM agustin.sanchez@ehu.es RI Pinilla-Alonso, Noemi/B-8583-2008; Fletcher, Leigh/D-6093-2011; Perez-Hoyos, Santiago/L-7543-2014; Rojas Palenzuela, Jose Felix/H-2782-2015; Simon, Amy/C-8020-2012; OI Fletcher, Leigh/0000-0001-5834-9588; Perez-Hoyos, Santiago/0000-0002-2587-4682; Rojas Palenzuela, Jose Felix/0000-0002-1102-5612; Simon, Amy/0000-0003-4641-6186; Sanchez-Lavega, Agustin/0000-0001-7355-1522; Hora, Joseph/0000-0002-5599-4650; Hueso, Ricardo/0000-0003-0169-123X NR 25 TC 47 Z9 47 U1 1 U2 22 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD JAN 24 PY 2008 VL 451 IS 7177 BP 437 EP 440 DI 10.1038/nature06533 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 253YS UT WOS:000252554100038 PM 18216848 ER PT J AU Farrell, WM Kaiser, ML Gurnett, DA Kurth, WS Persoon, AM Wahlund, JE Canu, P AF Farrell, W. M. Kaiser, M. L. Gurnett, D. A. Kurth, W. S. Persoon, A. M. Wahlund, J. E. Canu, P. TI Mass unloading along the inner edge of the Enceladus plasma torus SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SELF-CONSISTENT MODEL; SATURNS PLASMA; MAGNETOSPHERE; NEUTRALS; PLUME; ION; OH AB A major discovery made by the Cassini spacecraft at Saturn was the substantial mass ejection from the south pole of Enceladus. Previous studies show that this ejected gas can become ionized and subsequently load mass onto the connecting magnetic field lines near the moon. Radial diffusion then allows the mass-loaded field lines to move outward to similar to 15 R-s and inward to similar to 2 R-s, forming a plasma torus. We demonstrate herein that the mass is also '' unloaded '' along the inner edge of this plasma torus the edge incident with the plasma-absorbing A-ring. Interpreting down-drifting z-mode tones from active sites along the inner edge of the ion torus as emission near the local electron plasma frequency, f(pe), we can remotely-monitor this reduction in plasma density along the torus inner edge as a function time. We find that the down-drift of the z-mode tones corresponds typically to a plasma density change dn/dt similar to - 5x10(-4)/cm(3)-s and when integrated over an annulus defined by the outer edge of the A-ring, corresponds to a mass loss of similar to 40 kg/s. Using the z-mode tones, we also find locations where plasma mass from the ring-ionosphere is possibly loaded at 1 - 2 kg/s onto field lines near the Cassini gap. C1 [Farrell, W. M.; Kaiser, M. L.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Gurnett, D. A.; Kurth, W. S.; Persoon, A. M.] Univ Iowa, Dept Phys & Astron, Iowa City, IA 52240 USA. [Wahlund, J. E.] Swedish Inst Space Phys, SE-75121 Uppsala, Sweden. [Canu, P.] CETP, F-78140 Velizy Villacoublay, France. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM william.farrell@gsfc.nasa.gov RI Farrell, William/I-4865-2013; OI Kurth, William/0000-0002-5471-6202 NR 23 TC 13 Z9 13 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 23 PY 2008 VL 35 IS 2 AR L02203 DI 10.1029/2007GL032306 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 256TA UT WOS:000252751600004 ER PT J AU Ray, RD AF Ray, R. D. TI A preliminary tidal analysis of ICESat laser altimetry: Southern Ross Ice Shelf SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GLOBAL OCEAN TIDES; GEOSAT ALTIMETRY; SEA; SPECTROSCOPY; SATELLITE; MODEL AB Satellite laser altimetry could soon play a key role in mapping poorly known ocean tides underneath Antarctic ice shelves. The amount of ICESat data now collected over the southernmost part of the Ross Ice Shelf is sufficient to warrant direct tidal analysis. Tides are estimated here from ten operational ICESat periods, totaling 363 days. A response analysis helps overcome unfavorable tidal sampling, especially an S(2) correlation with the annual cycle. Comparisons of tidal estimates against independent station data show RMS constituent differences around 3 cm - still somewhat large, but an encouraging result for such a challenging region. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 21114 USA. RP Ray, RD (reprint author), NASA, Goddard Space Flight Ctr, Code 698, Greenbelt, MD 21114 USA. EM richard.ray@nasa.gov RI Ray, Richard/D-1034-2012 NR 22 TC 11 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 23 PY 2008 VL 35 IS 2 AR L02505 DI 10.1029/2007GL032125 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 256TA UT WOS:000252751600003 ER PT J AU Han, SC Simons, FJ AF Han, Shin-Chan Simons, Frederik J. TI Spatiospectral localization of global geopotential fields from the Gravity Recovery and Climate Experiment (GRACE) reveals the coseismic gravity change owing to the 2004 Sumatra-Andaman earthquake SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID TIME-VARIABLE GRAVITY; TENSILE FAULTS; HALF-SPACE; MASS-LOSS; DEFORMATION; VARIABILITY; MODELS; SYSTEM; SPHERE; SHEAR AB Regional mass fluxes owing to transport and adjustment within the Earth system that are implicitly contained in the monthly Gravity Recovery and Climate Experiment (GRACE) global geopotential coefficients are revealed by localizing global spectra using spatiospectrally concentrated window functions. We have analyzed 45 monthly global GRACE harmonic coefficient series in order to find the coseismic signature associated with the 2004 great Sumatra-Andaman earthquake. A significant gravity change after the earthquake is found in the time series of the GRACE coefficients after localization with a single band-limited window centered near the north of the island of Sumatra. This change is undetectable from the original global coefficients or from coefficients localized elsewhere on the globe. A step function with its discontinuity at 26 December 2004 usefully models the coseismic gravity change. The localized GRACE coefficients contain the jumps (associated with the earthquake) up to degree and order 55, although not all of them within this band produce changes that are statistically significant. The gravity change calculated from the localized GRACE coefficients displays 30 mu Gal peak-to-peak variations that are very well correlated with an independently derived seismic model based on elastic dislocation theory. C1 [Han, Shin-Chan] NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Greenbelt, MD 20771 USA. [Simons, Frederik J.] Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. [Han, Shin-Chan] Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. [Simons, Frederik J.] UCL, Dept Earth Sci, London, England. RP Han, SC (reprint author), NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Code 698, Greenbelt, MD 20771 USA. EM schan@puuoo.gsfc.nasa.gov; fjsimons@alum.mit.edu RI Simons, Frederik/A-3427-2008; Han, Shin-Chan/A-2022-2009 OI Simons, Frederik/0000-0003-2021-6645; NR 31 TC 23 Z9 25 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JAN 23 PY 2008 VL 113 IS B1 AR B01405 DI 10.1029/2007JB004927 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 256TX UT WOS:000252753900001 ER PT J AU Fok, MC Horne, RB Meredith, NP Glauert, SA AF Fok, Mei-Ching Horne, Richard B. Meredith, Nigel P. Glauert, Sarah A. TI Radiation belt environment model: Application to space weather nowcasting SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID RELATIVISTIC ELECTRON ACCELERATION; PITCH-ANGLE DIFFUSION; VAN-ALLEN RADIATION; MAGNETIC-FIELD; SOLAR-WIND; INNER MAGNETOSPHERE; GEOMAGNETIC STORMS; CHORUS WAVES; MECHANISMS; ENERGIES AB A data-driven physical model of the energetic electrons in the Earth's radiation belts, called the Radiation Belt Environment (RBE) model, has been developed to understand Earth's radiation belt dynamics and to predict the radiation conditions found there. This model calculates radiation belt electron fluxes from 10 keV to 6 MeV in the inner magnetosphere. It takes into account the realistic, time-varying magnetic field and considers effects of wave-particle interactions with whistler mode chorus waves. The storm on 23-27 October 2002 is simulated and the temporal evolutions of the radial and pitch angle distributions of energetic electrons are examined. The calculated electron fluxes agree very well with particle data from the low-orbit SAMPEX and LANL geosynchronous satellites, when the wave-particle interactions are taken into account during storm recovery. Flux increases begin near the plasmapause and then diffuse outward to higher L shells, consistent with previous findings from statistical studies. A simplified version of the RBE model is now running in real time to provide nowcasting of the radiation belt environment. With further improvements and refinements, this model will have important value in both scientific and space weather applications. C1 [Fok, Mei-Ching] NASA, Goddard Space Flight Ctr, Geosp Phys Lab, Greenbelt, MD 20771 USA. [Horne, Richard B.; Meredith, Nigel P.; Glauert, Sarah A.] British Antarctic Survey, Div Phys Sci, Cambridge CB3 0ET, England. RP Fok, MC (reprint author), NASA, Goddard Space Flight Ctr, Geosp Phys Lab, Code 673, Greenbelt, MD 20771 USA. EM mei-ching.h.fok@nasa.gov RI Fok, Mei-Ching/D-1626-2012; OI Meredith, Nigel/0000-0001-5032-3463; Horne, Richard/0000-0002-0412-6407 NR 70 TC 95 Z9 97 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 23 PY 2008 VL 113 IS A3 AR A03S08 DI 10.1029/2007JA012558 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 256UK UT WOS:000252755200001 ER PT J AU Carneal, JP Giovanardi, M Fuller, CR Palumbo, D AF Carneal, James P. Giovanardi, Marco Fuller, Chris R. Palumbo, Dan TI Re-Active Passive devices for control of noise transmission through a panel SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB Re-Active Passive devices have been developed to control low-frequency (<1000 Hz) noise transmission through a panel. These devices use a combination of active, re-active, and passive technologies packaged into a single unit to control a broad frequency range utilizing the strength of each technology over its best suited frequency range. The Re-Active Passive device uses passive constrained layer damping to cover relatively high-frequency range (> 150 Hz), reactive distributed vibration absorber to cover the medium-frequency range (50-200 Hz), and active control for controlling low frequencies (< 150 Hz). The actuator was applied to control noise transmission through a panel mounted in the Transmission Loss Test Facility at Virginia Tech. Experimental results are presented for the bare panel, and combinations of passive treatment, reactive treatment, and active control. Results indicate that three Re-Active Passive devices were able to increase the overall broadband (15-1000 Hz) transmission loss by 9.4 dB. These three devices added a total of 285 g to the panel mass of 6.0 kg, or approximately 5%, not including control electronics. (c) 2007 Elsevier Ltd. All rights reserved. C1 [Carneal, James P.] Virginia Polytech Inst & State Univ, Vibrat & Acoust Lab, Dept Mech Engn, Blacksburg, VA 24061 USA. [Giovanardi, Marco] Act Control Experts Inc, Cambridge, MA 02142 USA. [Fuller, Chris R.; Palumbo, Dan] NASA, Langley Res Ctr, Hampton, VA 23606 USA. RP Carneal, JP (reprint author), Virginia Polytech Inst & State Univ, Vibrat & Acoust Lab, Dept Mech Engn, Blacksburg, VA 24061 USA. EM jcarneal@vt.edu NR 13 TC 3 Z9 3 U1 1 U2 4 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JAN 22 PY 2008 VL 309 IS 3-5 BP 495 EP 506 DI 10.1016/j.jsv.2007.07.059 PG 12 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 240ZU UT WOS:000251627500006 ER PT J AU Pasek, MA AF Pasek, Matthew A. TI Rethinking early Earth phosphorus geochemistry SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE meteorites; origins of life; phosphonates; prebiotic; redox chemistry ID PRIMITIVE EARTH; PREBIOTIC PHOSPHORUS; PULSE-RADIOLYSIS; AQUEOUS-SOLUTION; IRON-METEORITES; SOLAR-SYSTEM; PHOSPHATE; ACIDS; LIFE; CHEMISTRY AB Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO32-), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks. C1 Univ Arizona, Lapl Ctr, NAI, NASA, Tucson, AZ 85719 USA. RP Pasek, MA (reprint author), Univ Arizona, Lapl Ctr, NAI, NASA, 1629 E Univ Blvd, Tucson, AZ 85719 USA. EM mpasek@lpl.arizona.edu RI Pasek, Matthew/A-7071-2008; OI Pasek, Matthew/0000-0003-1280-9555 NR 75 TC 72 Z9 76 U1 5 U2 39 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD JAN 22 PY 2008 VL 105 IS 3 BP 853 EP 858 DI 10.1073/pnas.0708205105 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 255HE UT WOS:000252647900007 PM 18195373 ER PT J AU Huang, X Braams, BJ Bowman, JM Kelly, REA Tennyson, J Groenenboom, GC van Der Avoird, A AF Huang, X. Braams, Bastiaan J. Bowman, Joel M. Kelly, Ross E. A. Tennyson, Jonathan Groenenboom, Gerrit C. van der Avoird, Ad TI New ab initio potential energy surface and the vibration-rotation-tunneling levels of (H(2)O)(2) and (D(2)O)(2) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIMER INTERMOLECULAR VIBRATIONS; TERAHERTZ LASER SPECTROSCOPY; DIPOLE-MOMENT SURFACES; WATER DIMER; SPECTRUM; ACCURACY; STRETCH AB We report a new full-dimensional potential energy surface (PES) for the water dimer, based on fitting energies at roughly 30 000 configurations obtained with the coupled-cluster single and double, and perturbative treatment of triple excitations method using an augmented, correlation consistent, polarized triple zeta basis set. A global dipole moment surface based on Moller-Plesset perturbation theory results at these configurations is also reported. The PES is used in rigorous quantum calculations of intermolecular vibrational frequencies, tunneling splittings, and rotational constants for (H(2)O)(2) and (D(2)O)(2), using the rigid monomer approximation. Agreement with experiment is excellent and is at the highest level reported to date. The validity of this approximation is examined by comparing tunneling barriers within that model with those from fully relaxed calculations. (c) 2008 American Institute of Physics. C1 [Huang, X.; Braams, Bastiaan J.; Bowman, Joel M.] Emory Univ, Dept Chem, Cherry L Emerson Ctr Sci Computat, Atlanta, GA 30322 USA. [Kelly, Ross E. A.; Tennyson, Jonathan] UCL, Dept Phys & Astron, London WC1E 6BT, England. [Groenenboom, Gerrit C.; van der Avoird, Ad] Radboud Univ Nijmegen, Inst Mol & Mat, NL-6525 ED Nijmegen, Netherlands. RP Huang, X (reprint author), NASA, Ames Res Ctr, Moffett Field, Mail Stop-245-6, Moffett Field, CA 94035 USA. EM jmbowma@emory.edu; A.vanderAvoird@theochem.ru.nl RI Kelly, Ross/C-3283-2008; Tennyson, Jonathan/I-2222-2012; Braams, Bastiaan/E-7687-2011; HUANG, XINCHUAN/A-3266-2013; Groenenboom, Gerrit/F-9692-2015; OI Tennyson, Jonathan/0000-0002-4994-5238; Braams, Bastiaan/0000-0003-4086-9969; Groenenboom, Gerrit/0000-0002-0920-3707 NR 26 TC 73 Z9 73 U1 0 U2 15 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 21 PY 2008 VL 128 IS 3 AR 034312 DI 10.1063/1.2822115 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 252UC UT WOS:000252471100022 PM 18205503 ER PT J AU Kospal, A Abraham, P Apai, D Ardila, DR Grady, CA Henning, T Juhasz, A Miller, DW Moor, A AF Kospal, A. Abraham, P. Apai, D. Ardila, D. R. Grady, C. A. Henning, Th. Juhasz, A. Miller, D. W. Moor, A. TI High-resolution polarimetry of Parsamian 21: revealing the structure of an edge-on FU Ori disc SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE techniques : polarimetric; circumstellar matter; stars : individual : Parsamian 21; stars : pre-main sequence; infrared : stars ID YOUNG STELLAR OBJECTS; HERBIG AE/BE STARS; ORIONIS OBJECTS; STANDARD STARS; SYSTEM; POLARIZATION; EVOLUTION; DUST; SPECTROSCOPY; CALIBRATION AB We present the first high spatial resolution near-infrared direct and polarimetric observations of Parsamian 21, obtained with the Nasmyth Adaptive Optics System-CONICA instrument at the Very Large Telescope (VLT). We complemented these measurements with archival infrared observations, such as Hubble Space Telescope (HST)/Wide Field Planetary Camera 2 (WFPC2) imaging, HST/Near Infrared Camera and Multi-Object Spectrometer (NICMOS) polarimetry, photometry with the Spitzer Space Telescope's Infrared Array Camera (IRAC) and Multiband Imaging Photometer (MIPS), spectroscopy with Spitzer's Infrared Spectrograph (IRS), as well as Infrared Space Observatory (ISO) photometry. Our main conclusions are as follows: (1) we argue that Parsamian 21 is probably an FU Orionis-type object (FUor); (2) Parsamian 21 is not associated with any rich cluster of young stars; (3) our measurements reveal a circumstellar envelope, a polar cavity and an edge-on disc; the disc seems to be geometrically flat and extends from approximately 48 to 360 au from the star; (4) the spectral energy distribution (SED) can be reproduced with a simple model of a circurnstellar disc and an envelope; (5) within the framework of an evolutionary sequence of FUors proposed by Green et al. and Quanz et al., Parsamian 21 can be classified as an intermediate-aged object. C1 [Kospal, A.; Abraham, P.; Moor, A.] Hungarian Acad Sci, Konkoly Observ Budapest, H-1525 Budapest, Hungary. [Apai, D.] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Apai, D.] NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. [Ardila, D. R.] CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. [Grady, C. A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Grady, C. A.] Eureka Sci, Greenbelt, MD 20771 USA. [Henning, Th.; Juhasz, A.] Max Planck Inst Astron, D-69117 Heidelberg, Germany. [Miller, D. W.] Univ Louisville, Dept Phys & Astron, Louisville, KY 40292 USA. RP Kospal, A (reprint author), Hungarian Acad Sci, Konkoly Observ Budapest, POB 67, H-1525 Budapest, Hungary. EM kospal@konkoly.hu RI Miller, David/H-8385-2012 OI Miller, David/0000-0002-4160-4228 NR 65 TC 10 Z9 10 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 21 PY 2008 VL 383 IS 3 BP 1015 EP 1028 DI 10.1111/j.1365-2966.2007.12557.x PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 258EP UT WOS:000252851500018 ER PT J AU Li, H Dowell, CD Kirby, L Novak, G Vaillancourt, JE AF Li, H. Dowell, C. D. Kirby, L. Novak, G. Vaillancourt, J. E. TI Design and initial performance of SHARP, a polarimeter for the SHARC-II camera at the Caltech Submillimeter Observatory SO APPLIED OPTICS LA English DT Article ID FAR-INFRARED POLARIMETRY; CLERK MAXWELL TELESCOPE; IMAGING POLARIMETER; 1ST DETECTION; SPARO 2003; POLARIZATION; CLOUDS; HERTZ; ARRAY AB We have developed a foreoptics module that converts the Submillimeter High Angular Resolution Camera generation II (SHARC-II) camera at the Caltech Submillimeter Observatory into a sensitive imaging polarimeter at wavelengths of 350 and 450 mu m. We refer to this module as "SHARP." SHARP splits the incident radiation into two orthogonally polarized beams that are then reimaged onto opposite ends of the 32 X 12 pixel detector array in SHARC-II. A rotating half-wave plate is used just upstream from the polarization-splitting optics. The effect of SHARP is to convert SHARC-II into a dual-beam 12 X 12 pixel polarimeter. A novel feature of SHARP's design is the use of a crossed grid in a submillimeter polarimeter. Here we describe the detailed optical design of SHARP and present results of tests carried out during our first few observing runs. At 350 mu m, the beam size (9 arc see), throughput (75%), and instrumental polarization (< 1%) are all very close to our design goals. 02008 Optical Society of America. C1 [Li, H.; Novak, G.] Northwestern Univ, Dept Phys & Astron, Evanston, IL 60208 USA. [Dowell, C. D.] Jet Propuls Lab, Pasadena, CA 91109 USA. [Dowell, C. D.; Vaillancourt, J. E.] CALTECH, Pasadena, CA 91125 USA. [Kirby, L.] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. [Kirby, L.; Vaillancourt, J. E.] Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Li, H (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM hli@cfa.harvard.edu NR 31 TC 32 Z9 32 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JAN 20 PY 2008 VL 47 IS 3 BP 422 EP 430 DI 10.1364/AO.47.000422 PG 9 WC Optics SC Optics GA 264DV UT WOS:000253266800014 PM 18204730 ER PT J AU Ajello, M Rau, A Greiner, J Kanbach, G Salvato, M Strong, AW Barthelmy, SD Gehrels, N Markwardt, CB Tueller, J AF Ajello, M. Rau, A. Greiner, J. Kanbach, G. Salvato, M. Strong, A. W. Barthelmy, S. D. Gehrels, N. Markwardt, C. B. Tueller, J. TI The swift bat X-ray survey. III. X-ray spectra and statistical properties SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; surveys; X-rays : binaries; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; SEYFERT 2 GALAXIES; BLACK-HOLE MASS; ALL-SKY SURVEY; LUMINOSITY FUNCTION; SLEW SURVEY; LATITUDE SURVEY; RADIO SOURCES; CATALOG; QUASARS AB In this concluding part of the series of three papers dedicated to the Swift BAT hard X-ray survey (BXS), we focus on the X-ray spectral analysis and statistical properties of the source sample. Using a dedicated method to extract time-averaged spectra of BAT sources, we show that Galactic sources have, generally, softer spectra than extragalactic objects and that Seyfert 2 galaxies are harder than Seyfert 1s. The averaged spectrum of all Seyfert galaxies is consistent with a power-law with a photon index of 2.00 +/- 0.07. The cumulative flux-number relation for the extragalactic sources in the 14-170 keV band is best described by a power-law with a slope alpha = 1.55 +/- 0.20 and a normalization of 9.6 +/- 1.9 x 10(-3) AGNs deg(-2) (or 396 +/- 80 AGNs all-sky) above a flux level of 2 x 10(-11) ergs cm(-2) s(-1) (similar to 0.85 mcrab). The integration of the cumulative flux per unit area indicates that BAT resolves 1%-2% of the X-ray background emission in the 14-170 keV band. A subsample of 24 extragalactic sources above the 4.5 sigma detection limit is used to study the statistical properties of AGNs. This sample is composed of local Seyfert galaxies (z = 0: 026, median value) and similar to 10% blazars. We find that 55% of the Seyfert galaxies are absorbed by column densities of N-H > 10(22) H atoms cm(-2) but that none is genuinely bona fide Compton thick. This study shows the capabilities of BAT to probe the hard X-ray sky to the millicrab level. C1 [Ajello, M.; Greiner, J.; Kanbach, G.; Strong, A. W.] Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. [Rau, A.; Salvato, M.] CALTECH, Caltech Opt Observ, Pasadena, CA 91125 USA. [Barthelmy, S. D.; Gehrels, N.; Markwardt, C. B.; Tueller, J.] NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. RP Ajello, M (reprint author), Max Planck Inst Extraterr Phys, Postfach 1312, D-85741 Garching, Germany. RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Tueller, Jack/D-5334-2012 NR 65 TC 62 Z9 62 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2008 VL 673 IS 1 BP 96 EP 113 DI 10.1086/524104 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RH UT WOS:000253454200008 ER PT J AU Overzier, RA Bouwens, RJ Cross, NJG Venemans, BP Miley, GK Zirm, AW Benitez, N Blakeslee, JP Coe, D Demarco, R Ford, HC Homeier, NL Illingworth, GD Kurk, JD Martel, AR Mei, S Oliveira, I Roettgering, HJA Tsvetanov, ZI Zheng, W AF Overzier, Roderik A. Bouwens, R. J. Cross, N. J. G. Venemans, B. P. Miley, G. K. Zirm, A. W. Benitez, N. Blakeslee, J. P. Coe, D. Demarco, R. Ford, H. C. Homeier, N. L. Illingworth, G. D. Kurk, J. D. Martel, A. R. Mei, S. Oliveira, I. Roettgering, H. J. A. Tsvetanov, Z. I. Zheng, W. TI Lyman break galaxies, Ly alpha emitters, and a radio galaxy in a protocluster at z=4.1(1,2) SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmology : observations; early universe; galaxies : clusters : general; galaxies : high-redshift; galaxies : individual (TN J1338-1942); galaxies : starburst; large-scale structure of universe ID HIGH-REDSHIFT GALAXIES; STAR-FORMING GALAXIES; LARGE-SCALE STRUCTURE; ULTRA DEEP FIELD; HUBBLE-SPACE-TELESCOPE; ULTRAVIOLET LUMINOSITY DENSITY; LOCAL STARBURST GALAXIES; COLOR-MAGNITUDE RELATION; EXTREMELY RED OBJECTS; FORMATION HISTORY AB We present deep HSTACS observations in g(475)r(625)i(775)z(850) toward the z = 4.1 radio galaxy TN J1338-1942 and its overdensity of >30 spectroscopically confirmed Ly alpha emitters (LAEs). We select 66 g(475) band dropouts to z(850,5 sigma) = 27, 6 of which are also LAEs. Although our color-color selection results in a relatively broad redshift range centered on z = 4.1, the field of TN J1338-1942 is richer than the average field at the >5 sigma significance, based on a comparison with GOODS. The angular distribution is filamentary with about half of the objects clustered near the radio galaxy, and a small, excess signal (2 sigma) in the projected pair counts at separations of theta < 10 '' is interpreted as being due to physical pairs. The LAEs are young (a few times 10(7) yr), small (< r(hl)> = 0.13 '') galaxies, and we derive a mean stellar mass of similar to 10(8)-10(9) M-circle dot based on a stacked K-s band image. We determine star formation rates, sizes, morphologies, and color-magnitude relations of the g(475)-dropouts and find no evidence for a difference between galaxies near TN J1338-1942 and in the field. We conclude that environmental trends as observed in clusters at much lower redshift are either not yet present or washed out by the relatively broad selection in redshift. The large galaxy overdensity, its corresponding mass overdensity, and the subclustering at the approximate redshift of TN J1338-1942 suggest the assemblage of a >10(14) M-circle dot structure, confirming that it is possible to find and study cluster progenitors in the linear regime at z greater than or similar to 4. C1 [Overzier, Roderik A.; Miley, G. K.; Oliveira, I.; Roettgering, H. J. A.] Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands. [Overzier, Roderik A.; Zirm, A. W.; Demarco, R.; Ford, H. C.; Homeier, N. L.; Martel, A. R.; Tsvetanov, Z. I.] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. [Bouwens, R. J.; Illingworth, G. D.] Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. [Cross, N. J. G.] Royal Observ, Edinburgh EH9 3HJ, Midlothian, Scotland. [Venemans, B. P.] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. [Benitez, N.; Coe, D.] CSIC, Inst Astrofis Andalucia, E-18008 Granada, Spain. [Blakeslee, J. P.] Washington State Univ, Dept Phys, Pullman, WA 99164 USA. [Kurk, J. D.] Max Planck Inst Astron, D-69117 Heidelberg, Germany. [Mei, S.] Observ Paris, Sect Meudon, GEPI, F-92195 Meudon, France. [Oliveira, I.; Tsvetanov, Z. I.] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. [Tsvetanov, Z. I.] NASA, Washington, DC 20546 USA. RP Overzier, RA (reprint author), Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands. NR 140 TC 68 Z9 68 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2008 VL 673 IS 1 BP 143 EP 162 DI 10.1086/524342 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RH UT WOS:000253454200012 ER PT J AU Woodruff, HC Tuthill, PG Monnier, JD Ireland, MJ Bedding, TR Lacour, S Danchi, WC Scholz, M AF Woodruff, H. C. Tuthill, P. G. Monnier, J. D. Ireland, M. J. Bedding, T. R. Lacour, S. Danchi, W. C. Scholz, M. TI The Keck aperture masking experiment: Multiwavelength observations of six Miira variables SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : interferometers; stars : AGB and post-AGB; stars : fundamental parameters; stars : individual (Mira, R hya, Chi Cyg, W Hya, R Leo, R cas); stars : late-type; techniques : interferometric ID ANGULAR RESOLUTION MEASUREMENTS; RICH MIRA VARIABLES; LATE-TYPE STARS; R-LEONIS; EFFECTIVE TEMPERATURES; DUST SHELLS; INTERFEROMETRIC OBSERVATIONS; IOTA/FLUOR INTERFEROMETER; INFRARED INTERFEROMETRY; DIAMETER MEASUREMENTS AB The angular diameters of six oxygen-rich Mira-type long-period variables have been measured at various NIR wavelengths using the aperture-masking technique in an extensive observing program from 1997 January to 2004 September. These data sets span many pulsation cycles of the observed objects and represent the largest study of multiwavelength, multiepoch interferometric angular diameter measurements on Mira stars to date. The calibrated visibility data of o Cet, R Leo, R Cas, WHya, chi Cyg, and R Hya are fitted using a uniform disk brightness distribution model to facilitate comparison between epochs, wavelengths, and with existing data and theoretical models. The variation of angular diameter as a function of wavelength and time is studied, and cyclic diameter variations are detected for all objects in our sample. These variations are believed to stem from time-dependent changes of density and temperature ( and hence varying molecular opacities) in different layers of these stars. The similarities and differences in behavior between these objects are analyzed and discussed in the context of existing theoretical models. Furthermore, we present time-dependent 3.08 mu m angular diameter measurements, probing for the first time these zones of probable dust formation, which show unforeseen sizes and are consistently out of phase with other NIR layers shown in this study. The S-type Mira chi Cyg exhibits significantly different behavior compared to the M-type Mira variables in this study, in both its NIR light curves and its diameter pulsation signature. Our data show that the NIR diameters predicted by current models are too small and need to incorporate additional and/or enhanced opacity mechanisms. Also, new tailored models are needed to explain the behavior of the S-type Mira chi Cyg. C1 [Woodruff, H. C.; Tuthill, P. G.; Bedding, T. R.; Lacour, S.; Scholz, M.] Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. [Monnier, J. D.] Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. [Ireland, M. J.] CALTECH, Pasadena, CA 91125 USA. [Ireland, M. J.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Scholz, M.] Univ Heidelberg, Inst Theoret Astrophys, D-69120 Heidelberg, Germany. RP Woodruff, HC (reprint author), Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. OI Ireland, Michael/0000-0002-6194-043X; Bedding, Timothy/0000-0001-5943-1460; Bedding, Tim/0000-0001-5222-4661 NR 68 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2008 VL 673 IS 1 BP 418 EP 433 DI 10.1086/523936 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RH UT WOS:000253454200032 ER PT J AU Kucera, TA Landi, E AF Kucera, T. A. Landi, E. TI An observation of low-level heating in an erupting prominence SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : prominences; Sun : UV radiation ID ABSORPTION FEATURES; TRANSITION REGION; KINK INSTABILITY; EUV-FILAMENT; ULTRAVIOLET MEASUREMENTS; DYNAMIC EVOLUTION; CORONAL EXPLORER; ATOMIC DATABASE; EMISSION-LINES; SOLAR AB Here we present multiwavelength observations of low-level heating in an erupting prominence observed in the UV and EUV over a wide range of temperatures and wavelengths by the Solar and Heliospheric Observatory (SOHO) Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument and the Transition Region and Coronal Explorer ( TRACE), and also in H alpha by the Yunnan Astronomical Observatory. The eruption occurred on 2004 April 30. The heating is relatively mild, leading only to the ionization of hydrogen and helium. It is also localized, occurring along the bottom edge of the erupting prominence and in a kinklike feature in the prominence. The heating is revealed as a decrease in the Lyman absorption relative to other parts of the prominence. This decrease results in an apparent increase in emission in all the lines observed by SUMER, especially those formed at temperatures of similar to 10(5) K. However, this is due to the disappearance of cooler absorbing material in the prominence rather than to an increase in these higher temperature species. These observations suggest that there may be low-level heating occurring in other erupting prominences that do not show heating to coronal temperatures. They also indicate that the prominence-corona transition region is best modeled with two or more structures along the line of sight. We discuss the results in terms of models of heating in erupting prominences and observations of Lyman absorption in prominences. C1 [Kucera, T. A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Landi, E.] USN, Res Lab, Washington, DC 20375 USA. [Landi, E.] Artep Inc, Ellicott City, MD 21402 USA. RP Kucera, TA (reprint author), NASA, Goddard Space Flight Ctr, Code 671, Greenbelt, MD 20771 USA. EM Therese.A.Kucera@nasa.gov RI Landi, Enrico/H-4493-2011; Kucera, Therese/C-9558-2012; OI Kucera, Therese/0000-0001-9632-447X NR 41 TC 8 Z9 8 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2008 VL 673 IS 1 BP 611 EP 620 DI 10.1086/523694 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RH UT WOS:000253454200047 ER PT J AU Daddi, E Dannerbauer, H Elbaz, D Dickinson, M Morrison, G Stern, D Ravindranath, S AF Daddi, E. Dannerbauer, H. Elbaz, D. Dickinson, M. Morrison, G. Stern, D. Ravindranath, S. TI Vigorous star formation with low efficiency in massive disk galaxies at z=1.5 SO ASTROPHYSICAL JOURNAL LETTERS LA English DT Article DE cosmology : observations; galaxies : evolution; galaxies : formation; galaxies : high-redshift; galaxies : starburst ID HUBBLE-DEEP-FIELD; SUBMILLIMETER GALAXIES; MOLECULAR GAS; HIGH-REDSHIFT; FORMING GALAXIES; DYNAMICAL EVOLUTION; INFRARED GALAXIES; RAPID FORMATION; Z-SIMILAR-TO-2; MULTIWAVELENGTH AB We present the first detection of molecular gas cooling CO emission lines from ordinary massive galaxies at z = 1.5. Two sources were observed with the IRAM Plateau de Bure Interferometer, selected to lie in the mass-p star formation rate correlation at their redshift, thus being representative of massive high-z galaxies. Both sources were detected with high confidence, yielding L-CO' similar to 2 x 10(10) K km s(-1) pc(2). For one of the sources we find evidence of velocity shear, implying CO sizes of similar to 10 kpc. With an infrared luminosity of L-FIR similar to 10(12) L-circle dot, these disklike galaxies are borderline ULIRGs but with star formation efficiency similar to that of local spirals, and an order of magnitude lower than that in submillimeter galaxies. This suggests a CO to total gas conversion factor similar to local spirals, gas consumption timescales approaching 1 Gyr or longer, and molecular gas masses reaching similar to 10(11) M-circle dot, comparable to or larger than the estimated stellar masses. These results support a major role of in situ gas consumption over cosmological timescales and with relatively low star formation efficiency, analogous to that of local spiral disks, for the formation of today's most massive galaxies and their central black holes. Given the high space density of similar galaxies, similar to 10(-4) Mpc(-3), this implies a widespread presence of gas-rich galaxies in the early universe, many of which might be within reach of detailed investigations of current and planned facilities. C1 [Daddi, E.; Elbaz, D.] Univ Paris Diderot, CNRS, CEA,CEA Saclay, DSM,DAPNIA,Serv Astropys,Lab AIM, F-91191 Gif Sur Yvette, France. [Dannerbauer, H.] MPIA, D-69117 Heidelberg, Germany. [Dickinson, M.] Natl Opt Astron Observ, Tucson, AZ 85719 USA. [Morrison, G.] Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. [Morrison, G.] Canada France Hawaii Telescope Corp, Kamuela, HI 96743 USA. [Stern, D.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Ravindranath, S.] IUCAA, Pune 411007, Maharashtra, India. RP Daddi, E (reprint author), Univ Paris Diderot, CNRS, CEA,CEA Saclay, DSM,DAPNIA,Serv Astropys,Lab AIM, Orme Merisiers, F-91191 Gif Sur Yvette, France. EM edaddi@cea.fr RI Daddi, Emanuele/D-1649-2012 OI Daddi, Emanuele/0000-0002-3331-9590 NR 43 TC 146 Z9 146 U1 0 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA J9 ASTROPHYS J LETT JI Astrophys. J. Lett. PD JAN 20 PY 2008 VL 673 IS 1 BP L21 EP L24 DI 10.1086/527377 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 291YG UT WOS:000255232800006 ER PT J AU Eastwood, JP Brain, DA Halekas, JS Drake, JF Phan, TD Oieroset, M Mitchell, DL Lin, RP Acuna, M AF Eastwood, J. P. Brain, D. A. Halekas, J. S. Drake, J. F. Phan, T. D. Oieroset, M. Mitchell, D. L. Lin, R. P. Acuna, M. TI Evidence for collisionless magnetic reconnection at Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND INTERACTION; GEOTAIL OBSERVATIONS; EARTHS MAGNETOPAUSE; FIELD; ACCELERATION; MAGNETOTAIL; SHEET AB Using data from Mars Global Surveyor (MGS) in combination with Particle-In-Cell (PIC) simulations of reconnection, we present the first direct evidence of collisionless magnetic reconnection at Mars. The evidence indicates that the spacecraft passed through the diffusion region where reconnection is initiated and observed the magnetic field signatures of differential electron and ion motion - the Hall magnetic field - that uniquely indicate the reconnection process. These are the first such in-situ reconnection observations at an astronomical body other than the Earth. Reconnection may be the source of Mars' recently discovered auroral activity and the changing boundaries of the closed regions of crustal magnetic field. C1 [Eastwood, J. P.; Brain, D. A.; Halekas, J. S.; Phan, T. D.; Oieroset, M.; Mitchell, D. L.; Lin, R. P.] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. [Drake, J. F.] Univ Maryland, Dept Phys, College Pk, MD 20742 USA. [Acuna, M.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Eastwood, JP (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. EM eastwood@ssl.berkeley.edu OI Halekas, Jasper/0000-0001-5258-6128 NR 33 TC 48 Z9 48 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 19 PY 2008 VL 35 IS 2 AR L02106 DI 10.1029/2007GL032289 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 254DU UT WOS:000252567400008 ER PT J AU Kataoka, R Pulkkinen, A AF Kataoka, Ryuho Pulkkinen, Antti TI Geomagnetically induced currents during intense storms driven by coronal mass ejections and corotating interacting regions SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GROUND MAGNETIC-FIELDS; SOLAR-WIND VELOCITY; TIME DERIVATIVES; POWER-SYSTEMS; FLUCTUATIONS; NETWORK; PHASE AB Geomagnetically induced currents (GIC) flowing in ground-based conductor systems during large geomagnetic storms are one of the most significant space weather phenomena that affect our ground-based technological systems. Here we show that GIC activity in subauroral latitudes depends on the storm phase and on the interplanetary drivers, such as coronal mass ejections (CMEs) and corotating interacting regions (CIRs). For example, it is shown that GIC amplitudes are relatively small during CIR storms in comparison to CME storms. However, Pc3-5 pulsation activity during CIR storms drives long-lasting GIC in the local prenoon sector. Despite of the differences between CME and CIR storms, the relationship between GIC and the time derivative of the horizontal ground magnetic field is always the same. A novel power law equation is derived to accurately characterize the relation. C1 [Kataoka, Ryuho] RIKEN, Inst Phys & Chem Res, Computat Astrophys Lab, Wako, Saitama 3510198, Japan. [Kataoka, Ryuho] Nagoya Univ, Solar Terr Lab, Nagoya, Aichi, Japan. [Pulkkinen, Antti] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. [Pulkkinen, Antti] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kataoka, R (reprint author), RIKEN, Inst Phys & Chem Res, Computat Astrophys Lab, 2-1 Hirosawa, Wako, Saitama 3510198, Japan. EM ryuho@riken.jp; antti.pulkkinen@gsfc.nasa.gov NR 30 TC 10 Z9 11 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 19 PY 2008 VL 113 IS A3 AR A03S12 DI 10.1029/2007JA012487 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 254FH UT WOS:000252571300001 ER PT J AU Famiglietti, JS Ryu, DR Berg, AA Rodell, M Jackson, TJ AF Famiglietti, James S. Ryu, Dongryeol Berg, Aaron A. Rodell, Matthew Jackson, Thomas J. TI Field observations of soil moisture variability across scales SO WATER RESOURCES RESEARCH LA English DT Article ID SGP97 HYDROLOGY EXPERIMENT; REMOTE-SENSING FOOTPRINTS; SURFACE MOISTURE; WATER CONTENT; SPATIAL VARIABILITY; AMSR-E; TIME; SPACE; DYNAMICS; VEGETATION AB In this study, over 36,000 ground-based soil moisture measurements collected during the SGP97, SGP99, SMEX02, and SMEX03 field campaigns were analyzed to characterize the behavior of soil moisture variability across scales. The field campaigns were conducted in Oklahoma and Iowa in the central USA. The Oklahoma study region is sub-humid with moderately rolling topography, while the Iowa study region is humid with low-relief topography. The relationship of soil moisture standard deviation, skewness and the coefficient of variation versus mean moisture content was explored at six distinct extent scales, ranging from 2.5 m to 50 km. Results showed that variability generally increases with extent scale. The standard deviation increased from 0.036 cm(3)/cm(3) at the 2.5-m scale to 0.071 cm(3)/cm(3) at the 50-km scale. The log standard deviation of soil moisture increased linearly with the log extent scale, from 16 m to 1.6 km, indicative of fractal scaling. The soil moisture standard deviation versus mean moisture content exhibited a convex upward relationship at the 800-m and 50-km scales, with maximum values at mean moisture contents of roughly 0.17 cm(3)/cm(3) and 0.19 cm(3)/cm(3), respectively. An empirical model derived from the observed behavior of soil moisture variability was used to estimate uncertainty in the mean moisture content for a fixed number of samples at the 800-m and 50-km scales, as well as the number of ground-truth samples needed to achieve 0.05 cm(3)/cm(3) and 0.03 cm(3)/cm(3) accuracies. The empirical relationships can also be used to parameterize surface soil moisture variations in land surface and hydrological models across a range of scales. To our knowledge, this is the first study to document the behavior of soil moisture variability over this range of extent scales using ground-based measurements. Our results will contribute not only to efficient and reliable satellite validation, but also to better utilization of remotely sensed soil moisture products for enhanced modeling and prediction. C1 [Famiglietti, James S.] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92717 USA. [Ryu, Dongryeol; Jackson, Thomas J.] USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD USA. [Berg, Aaron A.] Univ Guelph, Dept Geog, Guelph, ON N1G 2W1, Canada. [Rodell, Matthew] NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Famiglietti, JS (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92717 USA. EM grlonline@agu.org RI Rodell, Matthew/E-4946-2012; Ryu, Dongryeol/C-5903-2008 OI Rodell, Matthew/0000-0003-0106-7437; Ryu, Dongryeol/0000-0002-5335-6209 NR 53 TC 201 Z9 205 U1 0 U2 94 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JAN 19 PY 2008 VL 44 IS 1 AR W01423 DI 10.1029/2006WR005804 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 254FV UT WOS:000252572700002 ER PT J AU Stoner, AW Laurel, BJ Hurst, TP AF Stoner, A. W. Laurel, B. J. Hurst, T. P. TI Using a baited camera to assess relative abundance of juvenile Pacific cod: Field and laboratory trials SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE bait; fish survey; habitat; Pacific cod; seagrass; video ID SEA DEMERSAL FISHES; GADUS-MORHUA; REEF FISH; UNDERWATER VIDEO; STEREO-VIDEO; HABITAT CHARACTERISTICS; ANOPLOPOMA-FIMBRIA; NORTHEAST ATLANTIC; STOCK ASSESSMENT; VISUAL CENSUS AB Juvenile fishes are sometimes difficult to survey because they occur in a variety of structurally complex habitats that are not readily sampled with traditional trawl or seine gear. Laboratory experiments and field sampling were conducted to determine whether a baited-camera system could be used effectively to survey age-0 gadids. Pacific cod (Gadus macrocephalus Tilesius), saffron cod (Eleginus gracilis Tilesius), and walleye pollock (Theragra chalcogramma Pallas) all responded to bait bags presented in the laboratory, with increased general activity and approaches to the bait. Pacific cod responded most strongly, and remained in close proximity to the bait bag. In nearshore habitats of Kodiak, Alaska, age-0 gadids (mostly Pacific cod) were quickly attracted to a baited-camera system. Arrival rates stabilized within 15-min, and several metrics for Pacific cod abundance taken from the video records were closely correlated with the numbers collected in seine hauls. Highest correlations occurred with the total number of fish arriving in camera view during 15-min sets (NFA(15)) and with the overall maximum number of fish observed at one time during the sets (MaxN(O)). The time for first arrival of fish in view (TFA) was not correlated significantly with the numbers of fish in seine collections. NFA(15) was also useful for age-1+ saffron cod. Occasionally, the presence of large fish had a negative effect on assessments of age-0 fish, but the impact was important only when the large fish were present continuously. The baited-camera system performed equally well in seagrass, kelp and open habitats, and can be used to rapidly assess the relative abundance of Pacific cod and selected other species in a wide range of habitats in shallow and deep water. Published by Elsevier B.V. C1 [Stoner, A. W.; Laurel, B. J.; Hurst, T. P.] NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fosjeroes Behav Ecol Program, Newport, OR 97365 USA. RP Stoner, AW (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fosjeroes Behav Ecol Program, Newport, OR 97365 USA. EM al.stoner@noaa.gov RI Hurst, Thomas/N-1401-2013 NR 49 TC 24 Z9 24 U1 3 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JAN 18 PY 2008 VL 354 IS 2 BP 202 EP 211 DI 10.1016/j.jembe.2007.11.008 PG 10 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 264MQ UT WOS:000253292100005 ER PT J AU Weinstein, S Pane, D Ernst, LA Warren-Rhodes, K Dohm, JM Hock, AN Piatek, JL Emani, S Lanni, F Wagner, M Fisher, GW Minkley, E Dansey, LE Smith, T Grin, EA Stubbs, K Thomas, G Cockell, CS Marinangeli, L Ori, GG Heys, S Teza, JP Moersch, JE Coppin, P Diaz, GC Wettergreen, DS Cabrol, NA Waggoner, AS AF Weinstein, S. Pane, D. Ernst, L. A. Warren-Rhodes, K. Dohm, J. M. Hock, A. N. Piatek, J. L. Emani, S. Lanni, F. Wagner, M. Fisher, G. W. Minkley, E. Dansey, L. E. Smith, T. Grin, E. A. Stubbs, K. Thomas, G. Cockell, C. S. Marinangeli, L. Ori, G. G. Heys, S. Teza, J. P. Moersch, J. E. Coppin, P. Diaz, G. Chong Wettergreen, D. S. Cabrol, N. A. Waggoner, A. S. TI Application of pulsed-excitation fluorescence imager for daylight detection of sparse life in tests in the Atacama Desert SO JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES LA English DT Article ID CHLOROPHYLL FLUORESCENCE; LIGHT AB A daylight fluorescence imager was deployed on an autonomous rover, Zoe, to detect life on the surface and shallow subsurface in regions of the Atacama Desert in Chile during field tests between 2003 and 2005. In situ fluorescent measurements were acquired from naturally fluorescing biomolecules such as chlorophyll and from specific fluorescent probes sprayed on the samples, targeting each of the four biological macromolecule classes: DNA, protein, lipid, and carbohydrate. RGB context images were also acquired. Preparatory reagents were applied to enhance the dye probe penetration and fluorescence intensity of chlorophyll. Fluorescence imager data sets from 257 samples were returned to the Life in the Atacama science team. A variety of visible life forms, such as lichens, were detected, and several of the dye probes produced signals from nonphotosynthetic microorganisms. C1 [Weinstein, S.; Pane, D.; Ernst, L. A.; Emani, S.; Lanni, F.; Fisher, G. W.; Minkley, E.; Dansey, L. E.; Waggoner, A. S.] Carnegie Mellon Univ, Mol Biosensor & Imaging Ctr, Pittsburgh, PA 15213 USA. [Warren-Rhodes, K.; Grin, E. A.; Cabrol, N. A.] NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. [Cockell, C. S.] Open Univ, Planetary & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. [Coppin, P.] Carnegie Mellon Univ, Eventscope, Pittsburgh, PA 15213 USA. [Dohm, J. M.] Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. [Diaz, G. Chong] Univ Catolica Norte, Antofagasta, Chile. [Wagner, M.; Smith, T.; Stubbs, K.; Heys, S.; Teza, J. P.; Wettergreen, D. S.] Carnegie Mellon Univ, Inst Robot, Pittsburgh, PA 15213 USA. [Hock, A. N.] Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. [Marinangeli, L.; Ori, G. G.] Int Res Sch Planetary Sci, Pescara, Italy. [Piatek, J. L.; Moersch, J. E.] Univ Tennessee, Dept Earth & Planetary Sci, Knoxville, TN 37996 USA. [Thomas, G.] Univ Iowa, GROK Lab, Iowa City, IA 52242 USA. [Warren-Rhodes, K.; Cabrol, N. A.] SETI Inst, Mountain View, CA USA. RP Weinstein, S (reprint author), Carnegie Mellon Univ, Mol Biosensor & Imaging Ctr, 4400 5th Ave, Pittsburgh, PA 15213 USA. RI Moersch, Jeffrey/F-7189-2010; Dohm, James/A-3831-2014 NR 27 TC 5 Z9 5 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-BIOGEO JI J. Geophys. Res.-Biogeosci. PD JAN 18 PY 2008 VL 113 IS G1 AR G01S90 DI 10.1029/2006JG000319 PG 11 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 254EK UT WOS:000252569000001 ER PT J AU Owe, M de Jeu, R Holmes, T AF Owe, Manfred de Jeu, Richard Holmes, Thomas TI Multisensor historical climatology of satellite-derived global land surface moisture SO JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE LA English DT Article ID VEGETATION OPTICAL DEPTH; SOUTHERN GREAT-PLAINS; MULTICHANNEL MICROWAVE RADIOMETER; SOIL-MOISTURE; AMSR-E; RADIOFREQUENCY INTERFERENCE; HYDROLOGY EXPERIMENT; RETRIEVAL; EMISSION; INDEX AB A historical climatology of continuous satellite-derived global land surface soil moisture is being developed. The data consist of surface soil moisture retrievals derived from all available historical and active satellite microwave sensors, including Nimbus-7 Scanning Multichannel Microwave Radiometer, Defense Meteorological Satellites Program Special Sensor Microwave Imager, Tropical Rainfall Measuring Mission Microwave Imager, and Aqua Advanced Microwave Scanning Radiometer for EOS, and span the period from November 1978 through the end of 2007. This new data set is a global product and is consistent in its retrieval approach for the entire period of data record. The moisture retrievals are made with a radiative transfer-based land parameter retrieval model. The various sensors have different technical specifications, including primary wavelength, spatial resolution, and temporal frequency of coverage. These sensor specifications and their effect on the data retrievals are discussed. The model is described in detail, and the quality of the data with respect to the different sensors is discussed as well. Examples of the different sensor retrievals illustrating global patterns are presented. Additional validation studies were performed with large-scale observational soil moisture data sets and are also presented. The data will be made available for use by the general science community. C1 [Owe, Manfred] NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. [de Jeu, Richard; Holmes, Thomas] Vrije Univ Amsterdam, Dept Geoenvironm Branch, Amsterdam, Netherlands. RP Owe, M (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RI Holmes, Thomas/F-4512-2010 OI Holmes, Thomas/0000-0002-4651-0079 NR 61 TC 338 Z9 345 U1 10 U2 51 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-EARTH JI J. Geophys. Res.-Earth Surf. PD JAN 18 PY 2008 VL 113 IS F1 AR F01002 DI 10.1029/2007JF000769 PG 17 WC Geosciences, Multidisciplinary SC Geology GA 254EO UT WOS:000252569400001 ER PT J AU Edgar, LA Frey, HV AF Edgar, Lauren A. Frey, Herbert V. TI Buried impact basin distribution on Mars: Contributions from crustal thickness data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWLANDS AB Crustal thickness data (derived from Mars Global Surveyor (MGS) gravity field and topographic data) exposes a number of circular thin areas (CTAs) that may represent deeply buried impact basins, which are often not visible in topography alone. A data set which combines quasi-circular depressions (QCDs) revealed by the Mars Orbiter Laser Altimeter (MOLA) on the MGS spacecraft with a population of non-QCD CTAs is a better estimate of the true crater retention ages of the buried surfaces of Mars. This study finds that all regions have older crater retention ages than previously thought based on QCDs alone. The highlands and lowlands appear to have the same basement crater retention age, but Tharsis is younger. C1 [Edgar, Lauren A.] Dartmouth Coll, Dept Earth Sci, Hanover, NH 03755 USA. [Frey, Herbert V.] NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Greenbelt, MD 20771 USA. RP Edgar, LA (reprint author), CALTECH, Div Geol & Planetary Sci, MC 170-25,1200 E California Blvd, Pasadena, CA 91125 USA. EM ledgar@caltech.edu; herbert.v.frey@nasa.gov NR 6 TC 6 Z9 6 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 17 PY 2008 VL 35 IS 2 AR L02201 DI 10.1029/2007GL031466 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 254DR UT WOS:000252567100004 ER PT J AU Rignot, E Steffen, K AF Rignot, E. Steffen, K. TI Channelized bottom melting and stability of floating ice shelves SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SATELLITE-RADAR INTERFEROMETRY; PETERMANN-GLETSCHER; GREENLAND; SHEET; MODEL; SEA; ANTARCTICA; THICKNESS; VELOCITY; NORTH AB The floating ice shelf in front of Petermann Glacier, in northwest Greenland, experiences massive bottom melting that removes 80% of its ice before calving into the Arctic Ocean. Detailed surveys of the ice shelf reveal the presence of 1 - 2 km wide, 200 - 400 m deep, sub-ice shelf channels, aligned with the flow direction and spaced by 5 km. We attribute their formation to the bottom melting of ice from warm ocean waters underneath. Drilling at the center of one of channel, only 8 m above sea level, confirms the presence of ice-shelf melt water in the channel. These deep incisions in ice-shelf thickness imply a vulnerability to mechanical break up and climate warming of ice shelves that has not been considered previously. C1 [Rignot, E.] Univ Calif Irvine, Irvine, CA 92717 USA. [Rignot, E.] Jet Propuls Lab, Pasadena, CA 91109 USA. [Steffen, K.] Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Rignot, E (reprint author), Univ Calif Irvine, Irvine, CA 92717 USA. EM erignot@uci.edu; konrad.steffen@colorado.edu RI Steffen, Konrad/C-6027-2013; Rignot, Eric/A-4560-2014 OI Steffen, Konrad/0000-0001-8658-1026; Rignot, Eric/0000-0002-3366-0481 NR 18 TC 68 Z9 69 U1 3 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 17 PY 2008 VL 35 IS 2 AR L02503 DI 10.1029/2007GL031765 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 254DR UT WOS:000252567100006 ER PT J AU D'Andrea, TM Zhang, X Jochnowitz, EB Lindeman, TG Simpson, CJSM David, DE Curtiss, TJ Morris, JR Ellison, GB AF D'Andrea, Timothy M. Zhang, Xu Jochnowitz, Evan B. Lindeman, T. G. Simpson, C. J. S. M. David, Donald E. Curtiss, Thomas J. Morris, John R. Ellison, G. Barney TI Oxidation of organic films by beams of hydroxyl radicals SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; MASTER CHEMICAL MECHANISM; MCM V3 PART; TROPOSPHERIC DEGRADATION; SUPERSONIC EXPANSION; ELECTRON-IMPACT; STATE-SELECTION; DIPOLE-MOMENT; OH RADICALS; SURFACES AB We have studied the oxidation of self-assembled monolayers (SAMs) of alkanes and alkenes with a thermal beam of OH radicals. The target films were produced by bonding alkane thiols and alkene thiols to a gold surface and the SAMs are mounted in a vacuum chamber at a base pressure of 10(-9) Torr. Hydroxyl radicals were produced by a corona discharge in an Ar/H2O2/water mixture. The resultant molecular beam was scanned by an electrostatic hexapole and the OH radicals [4 (+/- 1) x 10(11) OH radicals cm(-2) sec(-1)] were focused onto the target SAM. All of the hydroxyl radicals impinging on the SAM surface are rotationally (J '' <= 5/2) cold. The vibrational temperature of the radicals is estimated to be 1700-3400 K which implies that between 5% and 22% of the hydroxyl radical beam is OH upsilon-1 and the remainder (95% to 78%) is OH upsilon=vertical bar. The collision energy of the beam with the SAM is 333 cm(-1) corresponding to a 485 K thermal beam. We employed reflection/ absorption infrared spectroscopy (RAIRS) to monitor the reactivity of OH with an alkane and an alkene SAM. RAIRS demonstrated that a 10 min dose of OH radicals largely destroys the CH3- groups at the interface. This corresponds to a deposition of 2.4 x 10(14) OH cm(-2) or about 60% of the SAM monolayer. Oxidation of an undec-10-ene-1-thiol (HS(CH2)(9)HC = CH2) SAM with OH radicals proceeded more quickly with all the terminal alkenes, -CH = CH2, eliminated within 5 min following deposition of 1.2 x 10(14) radicals. We believe that the OH radicals initiate a radical-induced polymerization of the alkene film. C1 [D'Andrea, Timothy M.; Zhang, Xu; Jochnowitz, Evan B.; David, Donald E.; Ellison, G. Barney] Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. [Zhang, Xu] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Jochnowitz, Evan B.] Univ Basel, Inst Phys Chem, CH-4056 Basel, Switzerland. [Lindeman, T. G.] Colorado Coll, Dept Chem, Colorado Springs, CO 80903 USA. [Simpson, C. J. S. M.] Univ Oxford, Phys Chem Lab, Oxford OX1 3QZ, England. [David, Donald E.] Univ Colorado, Dept Chem & Biochem, Integrated Inst Design Facil, CIRES, Boulder, CO 80309 USA. [Curtiss, Thomas J.] Aerosp Corp, Los Angeles, CA 90009 USA. [Morris, John R.] Virginia Tech, Dept Chem, Blacksburg, VA 24061 USA. RP Ellison, GB (reprint author), Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA. EM barney@jila.colorado.edu NR 51 TC 14 Z9 14 U1 0 U2 33 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD JAN 17 PY 2008 VL 112 IS 2 BP 535 EP 544 DI 10.1021/jp7096108 PG 10 WC Chemistry, Physical SC Chemistry GA 250GE UT WOS:000252287200039 PM 18088112 ER PT J AU Castanho, ADDA Martins, JV Artaxo, P AF Castanho, Andrea D. de Almeida Martins, J. Vanderlei Artaxo, Paulo TI MODIS aerosol optical depth Retrievals with high spatial resolution over an urban area using the critical reflectance SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IMAGING SPECTRORADIOMETER; TROPOSPHERIC AEROSOL; ALGORITHM; VALIDATION; ABSORPTION; AMAZONIA; WATER; LAND AB [1] The retrieval of aerosol optical depth (Ta) over land by satellite remote sensing is still a challenge when a high spatial resolution is required. This study presents a tool that uses satellite measurements to dynamically identify the aerosol optical model that best represents the optical properties of the aerosol present in the atmosphere. We use aerosol critical reflectance to identify the single scattering albedo of the aerosol layer. Two case studies show that the Sao Paulo region can have different aerosol properties and demonstrates how the dynamic methodology works to identify those differences to obtain a better T a retrieval. The methodology assigned the high single scattering albedo aerosol model (pi o( lambda = 0.55) = 0.90) to the case where the aerosol source was dominated by biomass burning and the lower pi(o) model (pi(o) (lambda = 0.55) = 0.85) to the case where the local urban aerosol had the dominant influence on the region, as expected. The dynamic methodology was applied using cloud-free data from 2002 to 2005 in order to retrieve Ta with Moderate Resolution Imaging Spectroradiometer ( MODIS). These results were compared with collocated data measured by AERONET in Sao Paulo. The comparison shows better results when the dynamic methodology using two aerosol optical models is applied (slope 1.06 +/- 0.08 offset 0.01 +/- 0.02 r(2) 0.6) than when a single and fixed aerosol model is used (slope 1.48 +/- 0.11 and offset - 0.03 +/- 0.03 r(2) 0.6). In conclusion the dynamical methodology is shown to work well with two aerosol models. Further studies are necessary to evaluate the methodology in other regions and under different conditions. C1 [Castanho, Andrea D. de Almeida] MIT, Cambridge, MA 02139 USA. [Martins, J. Vanderlei] Univ Maryland Baltimore Cty, JCET, Baltimore, MD 21228 USA. [Martins, J. Vanderlei] NASA, Goddard Space Flight Ctr, New York, NY 10025 USA. [Artaxo, Paulo] Univ Sao Paulo, BR-05508 Sao Paulo, Brazil. RP Castanho, ADDA (reprint author), MIT, 77 Massachusetts Ave,B54-1411, Cambridge, MA 02139 USA. EM castanho@mit.edu RI Artaxo, Paulo/E-8874-2010 OI Artaxo, Paulo/0000-0001-7754-3036 NR 24 TC 15 Z9 15 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 16 PY 2008 VL 113 IS D2 AR D02201 DI 10.1029/2007JD008751 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 254EE UT WOS:000252568400003 ER PT J AU Steyaert, LT Knox, RG AF Steyaert, Louis T. Knox, Robert G. TI Reconstructed historical land cover and biophysical parameters for studies of land-atmosphere interactions within the eastern United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID URBAN AREAS; AVHRR DATA; CLIMATE; VEGETATION; IMPACT; WEATHER; MODELS; CARBON; PREDICTION; CROPLANDS AB [1] Over the past 350 years, the eastern half of the United States experienced extensive land cover changes. These began with land clearing in the 1600s, continued with widespread deforestation, wetland drainage, and intensive land use by 1920, and then evolved to the present-day landscape of forest regrowth, intensive agriculture, urban expansion, and landscape fragmentation. Such changes alter biophysical properties that are key determinants of land-atmosphere interactions ( water, energy, and carbon exchanges). To understand the potential implications of these land use transformations, we developed and analyzed 20-km land cover and biophysical parameter data sets for the eastern United States at 1650, 1850, 1920, and 1992 time slices. Our approach combined potential vegetation, county-level census data, soils data, resource statistics, a Landsat-derived land cover classification, and published historical information on land cover and land use. We reconstructed land use intensity maps for each time slice and characterized the land cover condition. We combined these land use data with a mutually consistent set of biophysical parameter classes, to characterize the historical diversity and distribution of land surface properties. Time series maps of land surface albedo, leaf area index, a deciduousness index, canopy height, surface roughness, and potential saturated soils in 1650, 1850, 1920, and 1992 illustrate the profound effects of land use change on biophysical properties of the land surface. Although much of the eastern forest has returned, the average biophysical parameters for recent landscapes remain markedly different from those of earlier periods. Understanding the consequences of these historical changes will require land-atmosphere interactions modeling experiments. C1 [Steyaert, Louis T.] NASA, Goddard Space Flight Ctr, US Geol Survey, Ctr Earth Resources Observ & Sci, Greenbelt, MD 20771 USA. [Knox, Robert G.] NASA, Goddard Space Flight Ctr, Hydrospher & Biospher Sci Lab, Greenbelt, MD USA. RP Steyaert, LT (reprint author), NASA, Goddard Space Flight Ctr, US Geol Survey, Ctr Earth Resources Observ & Sci, Greenbelt, MD 20771 USA. EM stey_5589@verizon.net; robert.g.knox@nasa.gov RI Knox, Robert/E-9657-2011 NR 104 TC 27 Z9 28 U1 2 U2 21 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 16 PY 2008 VL 113 IS D2 AR D02101 DI 10.1029/2006JD008277 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 254EE UT WOS:000252568400001 ER PT J AU Parnell, J Bowden, S Osinski, GR Taylor, CW Lee, P AF Parnell, John Bowden, Stephen Osinski, Gordon R. Taylor, Colin W. Lee, Pascal TI The transfer of organic signatures from bedrock to sediment SO CHEMICAL GEOLOGY LA English DT Article DE Canadian Arctic; Haughton impact structure; hydrocarbon exploration; organic geochemistry; sediment recycling ID HAUGHTON IMPACT STRUCTURE; DEVON ISLAND; FLUID INCLUSION; HEINRICH EVENTS; QUARTZ-PEBBLES; NORTH-ATLANTIC; GOLD-BEARING; SNOW ALGAE; BAFFIN-BAY; OIL AB A case study in the Canadian Arctic demonstrates how an organic geochemical signature in the regional bedrock can be transferred by erosion and redeposition to younger geological formations and surface sediments. The hydrocarbon composition recorded in Laurentian (Lower Palaeozoic) carbonate bedrock was incorporated into overlying Miocene and Quaternary formations, and modern mass waste, alluvium, snow/ice, and proglacial deposits, and further distant in ice-rafted detritus. The retention of the original geological organic signature is reflected in consistent thermal maturities (hopane ratios) and environmental indicators (sterane distributions). In the modern sediments, the geological signature is variably mixed with a modern microbial organic signature reflected in high values of carbon preference index and diploptene. These data show that hydrocarbon occurrences in bedrock may be detected by the analysis of surface detritus, especially in carbonate terrains. However they also indicate that environmental signatures may be misleading if they are inherited from older geological units. (C) 2007 Elsevier B.V. All rights reserved. C1 [Parnell, John; Bowden, Stephen; Taylor, Colin W.] Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. [Osinski, Gordon R.] Canadian Space Agncy, St Hubert, PQ J3Y 8Y9, Canada. [Lee, Pascal] NASA, Ames Res Ctr, SETI Inst, Mars Inst, Moffett Field, CA 94035 USA. RP Parnell, J (reprint author), Univ Aberdeen, Dept Geol & Petr Geol, Aberdeen AB24 3UE, Scotland. EM J.Parnell@abdn.ac.uk NR 47 TC 3 Z9 3 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2541 J9 CHEM GEOL JI Chem. Geol. PD JAN 15 PY 2008 VL 247 IS 1-2 BP 242 EP 252 DI 10.1016/j.chemgeo.2007.10.025 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 261XY UT WOS:000253114500015 ER PT J AU Chizmadia, LJ Brearley, AJ AF Chizmadia, Lysa J. Brearley, Adrian J. TI Mineralogy, aqueous alteration, and primitive textural characteristics of fine-grained rims in the Y-791198CM2 carbonaceous chondrite: TEM observations and comparison to ALHA81002 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID WATER-BASALT INTERACTIONS; NATURAL-WATERS; CM CHONDRITE; SATURATION STATE; SOLAR NEBULA; MATRIX; DUST; DISSOLUTION; OLIVINE; PHYLLOSILICATES AB Transmission electron microscopy (TEM) was used to study the microtextural and mineralogical characteristics of fine-grained rims in the unbrecciated CM2 chondrites, Y-791198 and ALHA81002, in an effort to provide constraints on the origins of the rims themselves. Our TEM observations show that the rims in Y-791198 are composed of two distinct types of region, sulfide-poor and sulfide-rich, that are intermixed in a complex manner at the micron to submicron level. The sulfide-poor regions are largely composed of amorphous silicate material or nanocrystalline serpentine, but rare fibrous and coarse-grained serpentine grains have also been identified. No fine-grained cronstedtite or tochilinite were observed, although coarse-grained lumps of tochilinite are present in the rims. In contrast, the sulfide-rich regions are characterized by the presence of a myriad, nanometer-sized Fe, Ni sulfide grains (pentlandite with some Ni-rich pyrrhotite) embedded within an amorphous silicate similar in composition to that of the sulfide-poor regions. The sulfide-rich regions also contain rare phases such as olivine, and Fe, Ni metal grains with grain sizes that are always >100 nm in size. Z-contrast scanning transmission electron microscopy (STEM) reveals that the fine-grained rims consist of a mosaic of irregularly-shaped sulfide-poor and sulfide-rich-regions with sizes of about 0.2-0.5 mu m, that have been compacted together during parent body lithification. Despite aqueous alteration, the distinct mineralogical characteristics of these different regions are preserved on a fine-scale and probably represent primitive heterogeneity in the dust from which these rims formed. Serpentine is much better developed and more widespread in the fine-grained rims of ALHA81002 than Y-791198. Complex mats of serpentine fibers are commonly found and cronstedtite and tochilinite are plentiful. Anhydrous minerals such as olivine are rare and have usually been replaced by serpentine. Like Y-791198, all the fine-grained rims studied in ALHA81002 show the same mineral assemblages and textural characteristics throughout and between rims. The homogeneity of the mineralogy, textural relationships and degree of hydration in the rims of these two chondrites is more consistent with parent-body alteration than with pre-accretionary alteration. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Chizmadia, Lysa J.; Brearley, Adrian J.] Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Chizmadia, LJ (reprint author), Univ Hawaii, Inst Astron, NASA Astrobiol Inst, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM lysa@uprm.edu NR 87 TC 40 Z9 41 U1 1 U2 14 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JAN 15 PY 2008 VL 72 IS 2 BP 602 EP 625 DI 10.1016/j.gca.2007.10.019 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 253XG UT WOS:000252550300024 ER PT J AU Nemchin, AA Pidgeon, RT Whitehouse, MJ Vaughan, JP Meyer, C AF Nemchin, A. A. Pidgeon, R. T. Whitehouse, M. J. Vaughan, J. P. Meyer, C. TI SIMS U-Pb study of zircon from Apollo 14 and 17 breccias: Implications for the evolution of lunar KREEP SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID MOON; AGE; BASALTS; SURFACE; SYSTEMATICS; GREENLAND; CHEMISTRY; VOLCANISM; PETROLOGY; TERRANES AB We report the results of a SIMS U-Pb study of 112 zircons from breccia samples from the Apollo 14 and 17 landing sites. Zircon occurs in the breccia matrices as rounded, irregular shaped, broken and rarely euhedral grains and as constituent minerals in a variety of lithic clasts ranging in composition from ultra-mafic and mafic rocks to highly evolved granophyres. Crystallisation of zircon in magmatic rocks is governed by the zirconium saturation in the melt. As a consequence, the presence of zircon in mafic rocks on the Moon implies enrichment of their parent melts in the KREEP component. Our SIMS results show that the ages of zircons from mafic to ultramafic clasts range from ca. 4.35 Ga to ca. 4.00 Ga demonstrating multiple generations of KREEPy mafic and ultramafic magmas over this time period. Individual zircon clasts in breccia matrices have a similar age range to zircons in igneous clasts and all represent zircons that have been incorporated into the breccia from older parents. The age distributions of zircons from breccias from both the Apollo 14 and Apollo 17 landing sites are essentially identical in the range 4.35-4.20 Ga. However, whereas Apollo 14 zircons additionally show ages from 4.20 to 3.90 Ga, no zircons from Apollo 17 samples have primary ages less than ca. 4.20 Ga. Also, in contrast to previous suggestions that the magmatism in the lunar crust is continuous our results show that the zircon age distribution is uneven, with distinct peaks of magmatic activity at ca. 4.35 Ga, ca. 4.20 Ga in Apollo 14 and 17 and a possible third peak in zircons from Apollo 14 at ca. 4.00 Ga. To explain the differences in the zircon age distributions between the Apollo 14 and 17 landing sites we propose that episodes of KREEP magmatism were generated from a primary reservoir, and that this reservoir contracted over time towards the centre of Procellarum KREEP terrane. We attribute the peaks in KREEP magmatism to impact induced emplacement of KREEP magma from a primary mantle source or to a progressive thermal build-up in the mantle source until the temperature exceeds the threshold for generation of KREEP magma, which is transported into the crust by an unspecified possibly plume-like process. (C) 2007 Elsevier Ltd. All rights reserved. C1 [Nemchin, A. A.; Pidgeon, R. T.; Vaughan, J. P.] Curtin Univ Technol, Perth, WA 6845, Australia. [Whitehouse, M. J.] Swedish Museum Nat Hist, S-10405 Stockholm, Sweden. [Whitehouse, M. J.] NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Nemchin, AA (reprint author), Curtin Univ Technol, Perth, WA 6845, Australia. EM nemchina@kalg.curtin.edu.au RI Whitehouse, Martin/E-1425-2013 OI Whitehouse, Martin/0000-0003-2227-577X NR 54 TC 43 Z9 44 U1 1 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JAN 15 PY 2008 VL 72 IS 2 BP 668 EP 689 DI 10.1016/j.gca.2007.11.009 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 253XG UT WOS:000252550300027 ER PT J AU Sun, KJ Wincheski, RA Park, C AF Sun, Keun J. Wincheski, Russell A. Park, Cheol TI Magnetic property measurements on single wall carbon nanotube polyimide composites SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIPCO PROCESS; MONOXIDE; FILMS AB Magnetization measurements as a function of temperature and magnetic field were performed on polyimide nanocomposite samples containing various weight percentages of single wall carbon nanotubes. It was found that the magnetization of the composite, normalized to the mass of nanotube material in the sample, decreased with increasing weight percentage of nanotubes. It is possible that the interfacial coupling between the carbon nanotube (CNT) fillers and the polyimide matrix promotes the diamagnetic response from CNTs and reduces the total magnetization of the composite. The coercivity of the samples, believed to originate from the residual magnetic catalyst particles, was enhanced and had stronger temperature dependence as a result of the composite synthesis. These changes in magnetic properties can form the basis of a new approach to investigate the interfacial properties in the CNT nanocomposites through magnetic property measurements. (C) 2008 American Institute of Physics. C1 [Wincheski, Russell A.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. [Sun, Keun J.; Park, Cheol] Natl Inst Aerosp, Hampton, VA 23666 USA. RP Wincheski, RA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM russell.a.wincheski@nasa.gov NR 20 TC 10 Z9 10 U1 1 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD JAN 15 PY 2008 VL 103 IS 2 AR 023908 DI 10.1063/1.2832616 PG 6 WC Physics, Applied SC Physics GA 257TJ UT WOS:000252821100056 ER PT J AU Tsuang, BJ Chou, MD Zhang, Y Roesch, A Yang, K AF Tsuang, Ben-Jei Chou, Ming-Dah Zhang, Yuanchong Roesch, Andreas Yang, Kun TI Evaluations of land-ocean skin temperatures of the ISCCP satellite Retrievals and the NCEP and ERA reanalyses SO JOURNAL OF CLIMATE LA English DT Article ID EARTH RADIATION BUDGET; BOUNDARY-LAYER; SURFACE-TEMPERATURE; NCAR REANALYSIS; EXPERIMENT ERBE; MODEL; CLIMATE; DATABASE; VALIDATION; RESOLUTION AB This study evaluates the skin temperature (ST) datasets of the International Satellite Cloud Climatology Project (ISCCP) D satellite product, the ISCCP FD satellite product, the 40-yr ECMWF Re-Analysis (ERA-40), the NCEP-NCAR Reanalysis, and the NCEP-Department of Energy (DOE) Atmospheric Model Intercomparison Project (AMIP)-II Reanalysis. The monthly anomalies of all the datasets are correlated to each other and to most of the ground-truth stations with correlation coefficients > 0.50. To evaluate their qualities, the 5 ST datasets are used to calculate clear-sky (CS) outgoing longwave radiation (OLR) and upward surface longwave radiation (USLR); the results are compared with the Earth Radiation Budget Experiment (ERBE) satellite observation and 14 surface stations. The satellite-derived STs and ERA- 40 ST tend to bias high on hot deserts (e.g., Sahara Desert), and the reanalyzed STs tend to bias low in mountain areas ( e. g., Tibet). In Northern Hemisphere high-latitude regions ( tundra, wetlands, deciduous needle-leaf forests, and sea ice), the CS OLR anomalies calculated using the satellite-derived STs have higher correlations and lower root-mean-squared errors with the ERBE satellite observation than those derived from using the reanalyzed STs. ERA- 40 underestimates the amplitude of the seasonal ST over glaciers. All the reanalysis products (ERA-40, NCEP-NCAR, and NCEP-DOE AMIP-II) overestimate the ST during partial sea ice-covered periods in the middle-high-latitude oceans. Nonetheless, suspected spurious noises with an amplitude of 2 K in the satellite- derived STs produce a physically unviable anomaly over earth's surface where the amplitude of the anomaly is weak (such as open-water bodies, croplands, rain forest, grasslands, hot deserts, and cold deserts). Better land - ocean - ice schemes for a reanalysis should be developed for desert regions, high plateaus, fractional sea ice - covered oceans, and seasonally snow-covered lands, where the largest ST errors are identified. C1 [Tsuang, Ben-Jei] Natl Chung Hsing Univ, Dept Environm Engn, Taichung 402, Taiwan. [Chou, Ming-Dah] Natl Taiwan Univ, Dept Atmospher Sci, Taipei 10764, Taiwan. [Zhang, Yuanchong] Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY USA. [Roesch, Andreas] Inst Atmospher & Climate Change, Zurich, Switzerland. [Yang, Kun] Univ Tokyo, Dept Civil Engn, Tokyo 113, Japan. RP Tsuang, BJ (reprint author), Natl Chung Hsing Univ, Dept Environm Engn, Taichung 402, Taiwan. EM tsuang@nchu.edu.tw RI Yang, Kun/G-8390-2011 OI Yang, Kun/0000-0002-0809-2371 NR 58 TC 15 Z9 16 U1 1 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JAN 15 PY 2008 VL 21 IS 2 BP 308 EP 330 DI 10.1175/2007JCLI1502.1 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 256CF UT WOS:000252704600009 ER PT J AU Hanna, E Huybrechts, P Steffen, K Cappelen, J Huff, R Shuman, C Irvine-Fynn, T Wise, S Griffiths, M AF Hanna, Edward Huybrechts, Philippe Steffen, Konrad Cappelen, John Huff, Russell Shuman, Christopher Irvine-Fynn, Tristram Wise, Stephen Griffiths, Michael TI Increased runoff from melt from the Greenland Ice Sheet: A response to global warming SO JOURNAL OF CLIMATE LA English DT Article ID SSM/I BRIGHTNESS TEMPERATURES; NORTH-ATLANTIC OSCILLATION; SURFACE AIR-TEMPERATURE; MASS-BALANCE; EAST GREENLAND; CLIMATE-CHANGE; SEA-ICE; ACCELERATION; SIMULATIONS; VARIABILITY AB The authors attribute significantly increased Greenland summer warmth and Greenland Ice Sheet melt and runoff since 1990 to global warming. Southern Greenland coastal and Northern Hemisphere summer temperatures were uncorrelated between the 1960s and early 1990s but were significantly positively correlated thereafter. This relationship appears to have been modulated by the North Atlantic Oscillation, whose summer index was significantly ( negatively) correlated with southern Greenland summer temperatures until the early 1990s but not thereafter. Significant warming in southern Greenland since similar to 1990, as also evidenced from Swiss Camp on the west flank of the ice sheet, therefore reflects general Northern Hemisphere and global warming. Summer 2003 was the warmest since at least 1958 in coastal southern Greenland. The second warmest coastal summer 2005 had the most extensive anomalously warm conditions over the ablation zone of the ice sheet, which caused a record melt extent. The year 2006 was the third warmest in coastal southern Greenland and had the third-highest modeled runoff in the last 49 yr from the ice sheet; five of the nine highest runoff years occurred since 2001 inclusive. Significantly rising runoff since 1958 was largely compensated by increased precipitation and snow accumulation. Also, as observed since 1987 in a single composite record at Summit, summer temperatures near the top of the ice sheet have declined slightly but not significantly, suggesting the overall ice sheet is experiencing a dichotomous response to the recent general warming: possible reasons include the ice sheet's high thermal inertia, higher atmospheric cooling, or changes in regional wind, cloud, and/or radiation patterns. C1 [Hanna, Edward; Irvine-Fynn, Tristram; Wise, Stephen] Univ Sheffield, Dept Geog, Sheffield S10 2TN, S Yorkshire, England. [Huybrechts, Philippe] Vrije Univ Brussel, Dept Geog, Brussels, Belgium. [Steffen, Konrad; Huff, Russell] Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO USA. [Cappelen, John] Danish Metrol Inst, Copenhagen, Denmark. [Shuman, Christopher] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Griffiths, Michael] Univ Sheffield, Corp Informat & Comp Serv, Sheffield, S Yorkshire, England. RP Hanna, E (reprint author), Univ Sheffield, Dept Geog, Winter St, Sheffield S10 2TN, S Yorkshire, England. EM ehanna@sheffield.ac.uk RI Steffen, Konrad/C-6027-2013; Hanna, Edward/H-2219-2016 OI Steffen, Konrad/0000-0001-8658-1026; Hanna, Edward/0000-0002-8683-182X NR 46 TC 222 Z9 224 U1 10 U2 63 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD JAN 15 PY 2008 VL 21 IS 2 BP 331 EP 341 DI 10.1175/2007JCLI1964.1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 256CF UT WOS:000252704600010 ER PT J AU Ostrogorsky, AG Marin, C Churilov, A Volz, MP Bonner, WA Duffar, T AF Ostrogorsky, A. G. Marin, C. Churilov, A. Volz, M. P. Bonner, W. A. Duffar, T. TI Reproducible Te-doped InSb experiments in microgravity science Glovebox at the International Space Station SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE diffusion; directional solidification; segregation; microgravity conditions; InSb; semiconducting III-V materials ID SUBMERGED HEATER METHOD; EFFECTIVE SEGREGATION COEFFICIENT; VERTICAL BRIDGMAN CONFIGURATION; CRYSTAL-GROWTH; DIRECTIONAL SOLIDIFICATION; SOLUTE LAYER; ZERO GRAVITY; CONVECTION; BAFFLE; MODEL AB Four Te-doped InSb crystals were directionally solidified under microgravity conditions at the International Space Station (ISS). Three Te-doped InSb crystals were grown at R = 5 mm/h. One crystal was grown at R = 3.33 mm/h. The distribution of Te was measured using secondary ion mass spectroscopy (SIMS). The initial transients in Te concentration were found to be consistent, yielding a diffusivity of Te in InSb melts of D = 1 x 10(-5) cm(2)/s. One experiment revealed a diffusion controlled final transient. In all experiments, the charge was pressurized by a piston and spring device, to prevent de-wetting. (C) 2007 Elsevier B.V. All rights reserved. C1 [Ostrogorsky, A. G.; Marin, C.; Churilov, A.] Rensselaer Polytech Inst, Troy, NY 12180 USA. [Volz, M. P.] NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. [Bonner, W. A.] Crystallod Inc, Somerville, NJ USA. [Duffar, T.] ENSEEG, SIMAP, EPM, F-38402 St Martin Dheres, France. RP Ostrogorsky, AG (reprint author), Rensselaer Polytech Inst, Troy, NY 12180 USA. EM ostroa@rpi.edu NR 33 TC 3 Z9 4 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JAN 15 PY 2008 VL 310 IS 2 BP 364 EP 371 DI 10.1016/j.jcrysgro.2007.10.079 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 254YM UT WOS:000252623900017 ER PT J AU Eck, TF Holben, BN Reid, JS Sinyuk, A Dubovik, O Smirnov, A Giles, D O'Neill, NT Tsay, SC Ji, Q Al Mandoos, A Khan, MR Reid, EA Schafer, JS Sorokine, M Newcomb, W Slutsker, I AF Eck, T. F. Holben, B. N. Reid, J. S. Sinyuk, A. Dubovik, O. Smirnov, A. Giles, D. O'Neill, N. T. Tsay, S. -C. Ji, Q. Al Mandoos, A. Khan, M. Ramzan Reid, E. A. Schafer, J. S. Sorokine, M. Newcomb, W. Slutsker, I. TI Spatial and temporal variability of column-integrated aerosol optical properties in the southern Arabian Gulf and United Arab Emirates in summer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SKY RADIANCE MEASUREMENTS; ACE-ASIA; WAVELENGTH DEPENDENCE; RADIATIVE PROPERTIES; RELATIVE-HUMIDITY; WATER-VAPOR; IN-SITU; AERONET; DEPTH; DUST AB A mesoscale network of 14 AERONET Sun photometers was established in the UAE and adjacent Arabian Gulf from August through September 2004 as a component of the United Arab Emirates Unified Aerosol Experiment (UAE 2). These measurements allowed for spatial, temporal and spectral characterization of the complex aerosol mixtures present in this environment where coarse mode desert dust aerosols often mix with fine mode pollution aerosols largely produced by the petroleum industry. Aerosol loading was relatively high with 2-month averages of aerosol optical depth (AOD) at 500 nm (tau(a500)) ranging from 0.40 to 0.53. A higher fine mode fraction of AOD was observed over Arabian Gulf island sites with Angstrom exponent at 440-870 nm (alpha 440-870) of 0.77 as compared to an average of 0.64 over coastal sites and 0.50-0.57 at inland desert sites. During pollution events with alpha(440-870) > 1 the retrieved fine mode radius was larger over an island site than a desert site probably because of hygroscopic growth over the humid marine environment. For these same pollution cases, single scattering albedo (omega(o)) at all wavelengths was similar to 0.03 higher (less absorption) over the marine environment than over the desert, also consistent with aerosol humidification growth. At an inland desert location, the omega(o) at 440 nm remained relatively constant as Angstrom exponent varied since the fine mode pollution and coarse mode dust were both strong absorbers at short wavelengths. However, at longer wavelengths (675-1020 nm) the dust was much less absorbing than the pollution resulting in dynamic omega(o) as a function of a 440-870. C1 [Eck, T. F.; Smirnov, A.] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. [Eck, T. F.; Holben, B. N.; Sinyuk, A.; Smirnov, A.; Giles, D.; Tsay, S. -C.; Ji, Q.; Schafer, J. S.; Sorokine, M.; Newcomb, W.; Slutsker, I.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Reid, J. S.; Reid, E. A.] USN, Res Lab, Monterey, CA USA. [Sinyuk, A.; Giles, D.; Schafer, J. S.; Sorokine, M.; Newcomb, W.; Slutsker, I.] Sci Syst & Applicat Inc, Lanham, MD USA. [Dubovik, O.] Univ Lille, Opt Atmospher Lab, Villeneuve Dascq, France. [O'Neill, N. T.] Univ Sherbrooke, CARTEL, Sherbrooke, PQ J1K 2R1, Canada. [Ji, Q.] Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. [Al Mandoos, A.; Khan, M. Ramzan] Minist Presidential Affairs, Dept Atmospher Studies, Abu Dhabi, U Arab Emirates. RP Eck, TF (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RI Dubovik, Oleg/A-8235-2009; Schafer, Joel/A-3978-2010; Smirnov, Alexander/C-2121-2009; ECK, THOMAS/D-7407-2012; Reid, Jeffrey/B-7633-2014; Tsay, Si-Chee/J-1147-2014 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Reid, Jeffrey/0000-0002-5147-7955; NR 35 TC 67 Z9 67 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 15 PY 2008 VL 113 IS D1 AR D01204 DI 10.1029/2007JD008944 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 254EC UT WOS:000252568200001 ER PT J AU Chopping, M Su, L Rango, A Martonchik, JV Peters, DPC Laliberte, A AF Chopping, Mark Su, Lihong Rango, Albert Martonchik, John V. Peters, Debra P. C. Laliberte, Andrea TI Remote sensing of woody shrub cover in desert grasslands using MISR with a geometric-optical canopy reflectance model SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE canopy reflectance modeling; multi-angle remote sensing; MISR; BRDF ID ADJUSTED VEGETATION INDEX; SOUTHERN NEW-MEXICO; BIDIRECTIONAL REFLECTANCE; DESERTIFICATION; IMAGERY; ENCROACHMENT; ATTRIBUTES; RETRIEVAL; SURFACES; CLIMATE AB A new method is described for the retrieval of fractional cover of large woody plants (shrubs) at the landscape scale using moderate resolution multi-angle remote sensing data from the Multiangle Imaging SpectroRadiometer (MISR) and a hybrid geometric-optical (GO) canopy reflectance model. Remote sensing from space is the only feasible method for regularly mapping woody shrub cover over large areas, an important application because extensive woody shrub encroachment into former grasslands has been seen in and and semi-arid grasslands around the world during the last 150 years. The major difficulty in applying GO models in desert grasslands is the spatially dynamic nature of the combined soil and understory background reflectance: the background is important and cannot be modeled as either a Lambertian scatterer or by using a fixed bidirectional reflectance distribution function (BRDF). Candidate predictors of the background BRDF at the Sun-target-MISR angular sampling configurations included the volume scattering kernel weight from a Li-Ross BRDF model; diffuse brightness (p0) from the Modified Rahman-Pinty-Verstraete (MRPV) BRDF model; other Li-Ross kernel weights (isotropic, geometric); and MISR near-nadir bidirectional reflectance factors (BRFs) in the blue, green, and near infra-red bands. The best method was multiple regression on the weights of a kemel-driven model and MISR nadir camera blue, green, and near infra-red bidirectional reflectance factors. The results of forward modeling BRFs for a 5.25 km(2) area in the USDA, ARS Jomada Experimental Range using the Simple Geometric Model (SGM) with this background showed good agreement with the MISR data in both shape and magnitude, with only minor spatial discrepancies. The simulations were shown to be accurate in terms of both absolute value and reflectance anisotropy over all 9 MISR views and for a wide range of canopy configurations (r(2)=0.78, RMSE=0.013, N=3969). Inversion of the SGM allowed estimation of fractional shrub cover with a root mean square error (RMSE) of 0.03 but a relatively weak correlation (r(2)=0.19)with the reference data (shrub cover estimated from high resolution IKONOS panchromatic imagery). The map of retrieved fractional shrub cover was an approximate spatial match to the reference map. Deviations reflect the first-order approximation of the understory BRDF in the MISR viewing plane; errors in the shrub statistics; and the 12 month lag between the two data sets. (C) 2007 Published by Elsevier Inc. C1 [Chopping, Mark; Su, Lihong] Montclair State Univ, Montclair, NJ 07043 USA. [Rango, Albert; Peters, Debra P. C.; Laliberte, Andrea] USDA, ARS Jornada Expt Range, Las Cruces, NM 88003 USA. [Martonchik, John V.] NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Chopping, M (reprint author), Montclair State Univ, Montclair, NJ 07043 USA. EM chopping@pegasus.montclair.edu NR 37 TC 27 Z9 28 U1 1 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 19 EP 34 DI 10.1016/j.rse.2006.04.023 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300002 ER PT J AU Huang, D Knyazikhin, Y Wang, W Deering, DW Stenberg, P Shabanov, N Tan, B Myneni, RB AF Huang, Dong Knyazikhin, Yuri Wang, Weile Deering, Donald W. Stenberg, Pauline Shabanov, Nikolay Tan, Bin Myneni, Ranga B. TI Stochastic transport theory for investigating the three-dimensional canopy structure from space measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE stochastic radiative transfer; 3D canopy structure ID LEAF-AREA INDEX; PHOTOSYNTHETICALLY ACTIVE RADIATION; VEGETATION CANOPIES; DIGITAL IMAGES; BOREAL FOREST; BIDIRECTIONAL REFLECTANCE; AUTO-CORRELATION; SHOOT STRUCTURE; MODIS; MODELS AB Radiation reflected from vegetation canopies exhibits high spatial variation. Satellite-bome sensors measure the mean intensities emanating from heterogeneous vegetated pixels. The theory of radiative transfer in stochastic media provides the most logical linkage between satellite observations and the three-dimensional canopy structure through a closed system of simple equations which contains the mean intensity and higher statistical moments directly as its unknowns. Although this theory has been a highly active research field in recent years, its potential for satellite remote sensing of vegetated surfaces has not been fully realized because of the lack of models of a canopy pair-correlation function that the stochastic radiative transfer equations require. The pair correlation function is defined as the probability of finding simultaneously phytoelements at two points. This paper presents analytical and Monte Carlo generated pair correlation functions. Theoretical and numerical analyses show that the spatial correlation between phytoelements is primarily responsible for the effects of the three-dimensional canopy structure on canopy reflective and absorptive properties. The pair correlation function, therefore, is the most natural and physically meaningful measure of the canopy structure over a wide range of scales. The stochastic radiative transfer equations naturally admit this measure and thus provide a powerful means to investigate the three-dimensional canopy structure from space. Canopy reflectances predicted by the stochastic equations are assessed by comparisons with the PARABOLA measurements from coniferous and broadleaf forest stands in the BOREAS Southern Study Areas. The pair correlation functions are derived from data on tree structural parameters collected during field campaigns conducted at these sites. The simulated canopy reflectances compare well with the PARABOLA data. (C) 2007 Elsevier Inc. All rights reserved. C1 [Huang, Dong; Knyazikhin, Yuri; Wang, Weile; Shabanov, Nikolay; Tan, Bin; Myneni, Ranga B.] Boston Univ, Dept Geog, Boston, MA 02215 USA. [Deering, Donald W.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Stenberg, Pauline] Univ Helsinki, Dept Forest Ecol, FI-00014 Helsinki, Finland. RP Huang, D (reprint author), Brookhaven Natl Lab, Dept Environm Sci, 75 Rutherford Dr, Upton, NY 11973 USA. EM dhuang@bnl.gov RI Tan, Bin/G-1331-2012; Huang, Dong/H-7318-2014; Myneni, Ranga/F-5129-2012 OI Huang, Dong/0000-0001-9715-6922; NR 56 TC 38 Z9 39 U1 1 U2 17 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 35 EP 50 DI 10.1016/j.rse.2006.05.026 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300003 ER PT J AU Fang, HL Liang, SL Townshend, JR Dickinson, RE AF Fang, Hongliang Liang, Shunlin Townshend, John R. Dickinson, Robert E. TI Spatially and temporally continuous LAI data sets based on an integrated filtering method: Examples from North America SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE leaf area index (LAI); moderate resolution imaging spectroradiometer (MODIS); temporal and spatial filter; remote sensing; terra; ecosystem curve fitting (ECF) ID LEAF-AREA-INDEX; MODIS LAND PRODUCTS; NDVI TIME-SERIES; ETM PLUS; FOREST; VALIDATION; EXTRACTION; ALGORITHM; BIOSPHERE; BROADLEAF AB Leaf Area Index (LAI) is an important biophysical variable for characterizing the land surface vegetation. Global LAI product has been routinely produced from the MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellite platforms. However, the MODIS standard LAI product is not continuous both spatially and temporally. To fill the gaps and improve the quality, we have developed a data filtering algorithm. This filter, called the temporal spatial filter (TSF), integrates both spatial and temporal characteristics for different plant functional types. The spatial gaps are first filled with the multi-year averages of the same day. If the values are missing over all years, the pixel is filled with a new estimate using the vegetation continuous field-ecosystem curve fitting method. The TSF integrates both the multi-seasonal average trend (background) and the seasonal observation. We implement this algorithm using the MODIS Collection 4 LAI product over North America. Comparison of the TSF results with the Savitzky-Golay filter indicates that the TSF performs much better in restoring the spatial and temporal distribution of seasonal LAI trends. The new LAI product has been validated by comparing with field measurements and the derived LAI maps from ETM+ data at a broadleaf forest site and an agricultural site. The validation results indicate that the new LAI product agrees better with both the field measurements and LAI values obtained from the ETM+ than does the MODIS LAI standard product, which usually shows higher LAI values. (C) 2007 Elsevier Inc. All rights reserved. C1 [Fang, Hongliang; Liang, Shunlin; Townshend, John R.] Univ Maryland, Dept Geog, College Pk, MD 20742 USA. [Dickinson, Robert E.] Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Fang, HL (reprint author), NASA, GES DISC, Mclean, VA USA. EM hfang@geog.umd.edu RI liang, shunlin/C-2809-2015 NR 36 TC 55 Z9 65 U1 2 U2 26 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 75 EP 93 DI 10.1016/j.rse.2006.07.026 PG 19 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300006 ER PT J AU Sun, G Ranson, KJ Kimes, DS Blair, JB Kovacs, K AF Sun, G. Ranson, K. J. Kimes, D. S. Blair, J. B. Kovacs, K. TI Forest vertical structure from GLAS: An evaluation using LVIS and SRTM data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE forest structure; lidar; GLAS; LVIS; SRTM; height index; ICESat; lidar waveform ID SHUTTLE RADAR TOPOGRAPHY; LASER ALTIMETER; ABOVEGROUND BIOMASS; CLOSED-CANOPY; LIDAR; VALIDATION; HEIGHT; VEGETATION AB The Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat) is the first spaceborne lidar instrument for continuous global observation of the Earth. GLAS records a vertical profile of the returned laser energy from its footprint. To help understand the application of the data for forest spatial structure studies in our regional projects, an evaluation of the GLAS data was conducted using NASA's Laser Vegetation Imaging Sensor (LVIS) data in an area near NASA's Goddard Space Flight Center in Greenbelt, Maryland, USA. The tree height indices from airborne large-footprint lidars such as LVIS have been successfully used for estimation of forest structural parameters in many previous studies and served as truth in this study. The location accuracy of the GLAS footprints was evaluated by matching the elevation profile from GLAS with the Shuttle Radar Topography Mission (SRTM) DEM. The results confirmed the location accuracy of the GLAS geolocation, and showed a high correlation between the height of the scattering phase center from SRTM and the top tree height from GLAS data. The comparisons between LVIS and GLAS data showed that the GLAS waveform is similar to the aggregation of the LVIS waveforms within the GLAS footprint, and the tree height indices derived from the GLAS and LVIS waveforms were highly correlated. The best correlations were found between the 75% waveform energy quartiles of LVIS and GLAS (r(2) =0.82 for October 2003 GLAS data, and r(2)=0.65 for June 2005 GLAS data). The correlations between the 50% waveform energy quartiles of LVIS and GLAS were also high (0.77 and 0.66 respectively). The comparisons of the top tree height and total length of waveform of the GLAS data acquired in fall of 2003 and early summer of 2005 showed a several meter bias. Because the GLAS footprints from these two orbits did not exactly overlap, several other factors may have caused this observed difference, including difference of forest structures, seasonal difference of canopy structures and errors in identifying the ground peak of waveforms. (C) 2007 Elsevier Inc. All rights reserved. C1 [Sun, G.] Univ Maryland, Dept Geog, College Pk, MD 20742 USA. [Ranson, K. J.; Kimes, D. S.; Blair, J. B.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Kovacs, K.] Sci Syst & Applicat, Lanham, MD USA. RP Sun, G (reprint author), Univ Maryland, Dept Geog, College Pk, MD 20742 USA. EM guoqing@ltpmail.gsfc.nasa.gov RI Khachadourian, Diana/C-8513-2012; Ranson, Kenneth/G-2446-2012; Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 OI Ranson, Kenneth/0000-0003-3806-7270; NR 28 TC 150 Z9 168 U1 8 U2 40 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 107 EP 117 DI 10.1016/j.rse.2006.09.036 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300008 ER PT J AU Hashimoto, H Dungan, JL White, MA Yang, F Michaelis, AR Running, SW Nemani, RR AF Hashimoto, Hirofumi Dungan, Jennifer L. White, Michael A. Yang, Feihua Michaelis, Andrew R. Running, Steven W. Nemani, Ramakrishna R. TI Satellite-based estimation of surface vapor pressure deficits using MODIS land surface temperature data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE VDP; land surface temperature; MODIS ID REGIONAL EVAPOTRANSPIRATION; WATER-VAPOR; ALGORITHM; FOREST; PHOTOSYNTHESIS; INTERPOLATION; VARIABILITY; EVAPORATION; VALIDATION; PARAMETERS AB Vapor Pressure Deficit (VPD) is a principle mediator of global terrestrial CO2 uptake and water vapor loss through plant stomata. As such, methods to estimate VPD accurately and efficiently are critical for ecosystem and climate modeling efforts. Based on prior work relating energy partitioning, remotely sensed land surface temperature (LST), and VPD, we developed simple linear models to predict VPD using saturated vapor pressure calculated from MODIS LST at a number of different temporal and spatial resolutions. We developed and assessed the LST-VPD models using three data sets: (1) instantaneous and daytime average ground-based VPD and radiometric temperature from the Soil Moisture Experiments in 2002 (SMEX02); (2) daytime average VPD from AmeriFlux eddy covariance flux tower observations; and (3) estimated daytime average VPD from Global Surface Summary of Day (GSSD) observations. We estimated model parameters for VPD estimation both regionally (MODI I A2) and globally (MOD11 C2) with RMSE values ranging from .32 to .38 kPa. VPD was overestimated along coastlines and underestimated in and regions with low vegetation cover. Also, residuals were larger with higher VPDs because of the non-linear function of saturation vapor pressure with LST. Linear relationships were seen at multiple scales and appear useful for estimation purposes within a range of 0 to 2.5 kPa. (C) 2007 Elsevier Inc. All rights reserved. C1 [Hashimoto, Hirofumi; Michaelis, Andrew R.] Calif State Univ, Monterey, CA USA. [Hashimoto, Hirofumi] Univ Tokyo, Grad Sch Agr & Life Sci, Tokyo, Japan. [Dungan, Jennifer L.; Michaelis, Andrew R.; Nemani, Ramakrishna R.] NASA, Ames Res Ctr, Moffett Field, CA 94305 USA. [White, Michael A.] Utah State Univ, Dept Aquat Watershed & Earth Resources, Logan, UT 84322 USA. [Yang, Feihua] Univ Wisconsin, Dept Geog, Madison, WI 53706 USA. [Running, Steven W.] Univ Montana, NTSG, Missoula, MT 59812 USA. RP Hashimoto, H (reprint author), NASA, Ames Res Ctr, MS 242 2, Moffett Field, CA 94305 USA. EM hirofumi.hashimoto@gmail.com RI Dungan, Jennifer/G-9921-2016; OI Dungan, Jennifer/0000-0002-4863-1616; White, Michael/0000-0002-0238-8913 NR 38 TC 41 Z9 42 U1 2 U2 24 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 142 EP 155 DI 10.1016/j.rse.2007.04.016 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300011 ER PT J AU Garrigues, S Allard, D Baret, F Morisette, J AF Garrigues, S. Allard, D. Baret, F. Morisette, J. TI Multivariate quantification of landscape spatial heterogeneity using variogram models SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE spatial heterogeneity; spatial structure; length scale; moderate spatial resolution; landscape; multivariate variogram model; red and near infrared; reflectances; NDVI; stationarity ID REMOTE-SENSING ALGORITHMS; LINEAR COREGIONALIZATION; DIGITAL IMAGES; SOIL-MOISTURE; LEAF-AREA; FOREST; SCALE; DISAGGREGATION; REFLECTANCE; PARAMETERS AB The monitoring of earth surface processes at a global scale requires high temporal frequency remote sensing observations provided up to now by moderate spatial resolution sensors (from 250 m to 7 kin). Non-linear estimation processes of land surface variables derived from remote sensing data can be biased by the surface spatial heterogeneity within the moderate spatial resolution pixel. Quantifying this surface spatial heterogeneity is thus required to correct non-linear estimation processes of land surface variables. The first step in this process is to properly characterize the scale of spatial variation of the processes structuring the landscape. Since the description of land surface processes generally involves various spectral bands, a multivariate approach to characterize the surface spatial heterogeneity from multi-spectral remote sensing observations has to be established. This work aims at quantifying the landscape spatial heterogeneity captured by red and near infrared high spatial resolution images using direct and cross-variograms modeled together with the geostatistical linear model of coregionalization. This model quantifies the overall spatial variability and correlation of red and near infrared reflectances over the scene. In addition, it provides an explicit understanding of the landscape spatial structures captured by red and near infrared reflectances and is thus appropriate to describe landscapes composed of areas with contrasted red and near infrared spectral properties. The application of the linear model of coregionalization to 18 contrasted landscapes provides a spatial signature of red and near infrared spectral properties characterizing each type of landscape. Low vegetation cover sites are characterized by positive spatial correlation between red and near infrared. The mosaic pattern of vegetation fields and bare soil fields over crop sites generates high and negative spatial correlation between red and near infrared and increases the spatial variability of red and near infrared. On forest sites, the important amount of vegetation limits the spatial variability of red and the shadow effects mainly captured by near infrared induce a low and positive spatial correlation between red and near infrared. Finally, the linear model of coregionalization applied to red and near infrared is shown to be more powerful than the univariate variogram modeling applied to NDVI because the second order stationarity hypothesis on which variogram modeling relies is more frequently verified for red and near infrared than for NDVI. (C) 2007 Elsevier Inc. All rights reserved. C1 [Morisette, J.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Garrigues, S.] Univ Maryland, Earth Syst Sci interdisciplinary Ctr, College Pk, MD 20742 USA. [Allard, D.] INRA, Biostat & Spatial Proc Unit, Avignon, France. [Baret, F.] INRA, UMR1114, Avignon, France. RP Garrigues, S (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 614 4, Greenbelt, MD 20771 USA. EM Sebastien.garrigues@gsfe.nasa.gov RI Baret, Fred/C-4135-2011 OI Baret, Fred/0000-0002-7655-8997 NR 43 TC 31 Z9 36 U1 2 U2 20 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN 15 PY 2008 VL 112 IS 1 BP 216 EP 230 DI 10.1016/j.rse.2007.04.017 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 254GL UT WOS:000252574300016 ER PT J AU Pint, C Bozzolo, G Garces, JE AF Pint, Cary Bozzolo, Guillermo Garces, Jorge E. TI Growth and alloy formation of Fe on flat and stepped Pt substrates SO SURFACE SCIENCE LA English DT Article DE surface segregation; computer simulations; Monte Carlo simulations; iron; platinum ID ULTRATHIN FE; ALPHA,BETA-UNSATURATED ALDEHYDES; VICINAL SURFACES; METAL CHAINS; FILMS; DEPOSITION; MAGNETISM; TEMPERATURE; FE/CU(100); ISLANDS AB Atomistic modeling of subsurface Fe-Pt alloy formation upon deposition of Fe on Pt(1 0 0), Pt(1 1 1), and vicinal Pt(9 9 7) substrates using the BFS method for alloys is presented. The simulation results indicate preference for Fe atoms to occupy sites in the Pt subsurface layers and form an ordered alloy phase upon deposition on a low-index Pt surface. This behavior results in Pt surface segregation leading to nucleation of 3D Pt islands. A similar atom-by-atom analysis of Fe deposition on a stepped Pt(9 9 7) substrate indicates that Fe atoms prefer decoration of Pt step edges prior to formation of the ordered Fe-Pt surface alloy, where the ordered alloy is observed to form at the edges of the monoatomic surface steps. The pathway for Fe-Pt subsurface alloy formation is explained by a simple picture emerging from the competition between BFS strain and chemical energy contributions. (C) 2007 Elsevier B.V. All rights reserved. C1 [Bozzolo, Guillermo] Ohio Aerosp Inst, Cleveland, OH USA. [Pint, Cary] Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. [Bozzolo, Guillermo] NASA, Glenn Res Ctr, Cleveland, OH USA. [Garces, Jorge E.] Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. RP Bozzolo, G (reprint author), Ohio Aerosp Inst, 22800 Cedar Point Rd, Cleveland, OH USA. EM GuillermoBozzolo@oai.org RI Pint, Cary/C-5053-2009; Pint, Cary/I-6785-2013 NR 33 TC 4 Z9 4 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JAN 15 PY 2008 VL 602 IS 2 BP 559 EP 570 DI 10.1016/j.susc.2007.11.003 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 264HH UT WOS:000253277900024 ER PT J AU Cattell, C Wygant, JR Goetz, K Kersten, K Kellogg, PJ von Rosenvinge, T Bale, SD Roth, I Temerin, M Hudson, MK Mewaldt, RA Wiedenbeck, M Maksimovic, M Ergun, R Acuna, M Russell, CT AF Cattell, C. Wygant, J. R. Goetz, K. Kersten, K. Kellogg, P. J. von Rosenvinge, T. Bale, S. D. Roth, I. Temerin, M. Hudson, M. K. Mewaldt, R. A. Wiedenbeck, M. Maksimovic, M. Ergun, R. Acuna, M. Russell, C. T. TI Discovery of very large amplitude whistler-mode waves in Earth's radiation belts SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ELECTRON ACCELERATION; INNER MAGNETOSPHERE; RESONANT DIFFUSION; CHORUS; SPACECRAFT; FLUXES AB During a passage through the Earth's dawn-side outer radiation belt, whistler-mode waves with amplitudes up to more than similar to 240 mV/m were observed by the STEREO S/WAVES instrument. These waves are an order of magnitude larger than previously observed for whistlers in the radiation belt. Although the peak frequency is similar to whistler chorus, there are distinct differences from chorus, in addition to the larger amplitudes, including the lack of drift in frequency and the oblique propagation with a large longitudinal electric field component. Simulations show that these large amplitude waves can energize an electron by the order of an MeV in less than 0.1s, explaining the rapid enhancement in electron intensities observed between the STEREO-B and STEREO-A passage during this event. Our results show that the usual theoretical models of electron energization and scattering via small-amplitude waves, with timescales of hours to days, may be inadequate for understanding radiation belt dynamics. C1 [Cattell, C.; Wygant, J. R.; Goetz, K.; Kersten, K.; Kellogg, P. J.] Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. [von Rosenvinge, T.; Acuna, M.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Bale, S. D.; Roth, I.; Temerin, M.] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. [Bale, S. D.] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. [Hudson, M. K.] Dartmouth Coll, Dept Phys, Hanover, NH 03755 USA. [Mewaldt, R. A.] CALTECH, Downs Lab, Pasadena, CA 91125 USA. [Wiedenbeck, M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Maksimovic, M.] Observ Paris, Lab Etud Spatiales & Instrument & Astrophys, F-92195 Meudon, France. [Ergun, R.] Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA. [Russell, C. T.] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. RP Cattell, C (reprint author), Univ Minnesota, Sch Phys & Astron, 116 Church St SE, Minneapolis, MN 55455 USA. EM cattell@fields.space.umn.edu RI Bale, Stuart/E-7533-2011; OI Bale, Stuart/0000-0002-1989-3596; Cattell, Cynthia/0000-0002-3805-320X NR 31 TC 128 Z9 128 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 12 PY 2008 VL 35 IS 1 AR L01105 DI 10.1029/2007GL032009 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 251GU UT WOS:000252362100003 ER PT J AU Lee, T McPhaden, MJ AF Lee, Tong McPhaden, Michael J. TI Decadal phase change in large-scale sea level and winds in the Indo-Pacific region at the end of the 20th century SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MERIDIONAL OVERTURNING CIRCULATION; INDIAN-OCEAN; VARIABILITY; GYRE AB Satellite observations of sea surface height (SSH) and wind stress for the period of 1993-2006 reveal a near-coherent large-scale decadal variability in much of the Indo-Pacific region with a phase change at the turn of the 20th century. Trade wind variations in the tropical Pacific and South Indian Ocean are anti-correlated with each other as are SSH differences across these two basins, implying anti-correlated variation of the subtropical cells in the two oceans. Decadal changes in large-scale SSH in the extratropics are mostly associated with well-defined patterns of wind stress curl indicating a near-coherent decadal variation in the strength of subtropical and subpolar gyres. Together, these variations reflect a linkage in the circulation of the Pacific and Indian Oceans via atmospheric and oceanic bridges. The phase change in the tropical Pacific tends to occur earlier than elsewhere, suggesting a potential role of the tropical Pacific in regulating decadal variability of the entire region. C1 [Lee, Tong] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [McPhaden, Michael J.] NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Lee, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tong.lee@jpl.nasa.gov RI McPhaden, Michael/D-9799-2016 NR 18 TC 71 Z9 73 U1 1 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 12 PY 2008 VL 35 IS 1 AR L01605 DI 10.1029/2007GL032419 PG 7 WC Geosciences, Multidisciplinary SC Geology GA 251GU UT WOS:000252362100005 ER PT J AU Le, G Zheng, Y Russell, CT Pfaff, RF Slavin, JA Lin, N Mozer, F Parks, G Wilber, M Petrinec, SM Lucek, EA Reme, H AF Le, G. Zheng, Y. Russell, C. T. Pfaff, R. F. Slavin, J. A. Lin, N. Mozer, F. Parks, G. Wilber, M. Petrinec, S. M. Lucek, E. A. Reme, H. TI Flux transfer events simultaneously observed by Polar and Cluster: Flux rope in the subsolar region and flux tube addition to the polar cusp SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HYBRID-DRIFT INSTABILITY; HIGH-ALTITUDE CUSP; SINGLE X-LINE; HIGH-LATITUDE; DAYSIDE MAGNETOPAUSE; MAGNETIC RECONNECTION; NORTHWARD IMF; PLASMA-WAVES; SIGNATURES; ION AB In this paper we present observational evidence of a flux transfer event observed simultaneously at low-latitude by Polar and at high-latitude by Cluster. This event occurs on 21 March 2002, when both Cluster and Polar are located near local noon but with a large latitudinal separation. During the event, Cluster is moving outbound from the polar cusp to the magnetosheath and Polar is in the magnetosheath near the equatorial magnetopause. The observations show that a flux transfer event occurs between the equator and the northern cusp. Polar and Cluster observe the FTE's two open flux tubes: Polar encounters the southward moving flux tube near the equator and Cluster encounters the northward moving flux tube at high latitude. The low-latitude FTE appears to be a flux rope with helical magnetic field lines as it has a strong core field and the magnetic field component in the boundary normal direction exhibits a strong bipolar variation. Unlike the low-latitude FTE, the high-latitude FTE observed by Cluster does not exhibit the characteristic bipolar perturbation in the magnetic field. However, the plasma data clearly reveal its open flux tube configuration. It shows that the magnetic field lines have straightened inside the FTE and become more aligned to the neighboring flux tubes as it moves to the cusp. Enhanced electrostatic fluctuations have been observed within the FTE core, both at low and high latitudes. This event provides a unique opportunity to understand high-latitude FTE signatures and the nature of time-varying reconnection. It shows that existing FTE models cannot accommodate all the features in global observations, and coordinated measurements from largely spaced multiple spacecraft place important constraints which are crucial to the development and refinement of FTE models. C1 [Le, G.; Pfaff, R. F.; Slavin, J. A.] NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. [Lin, N.; Mozer, F.; Parks, G.; Wilber, M.] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. [Lucek, E. A.] Univ London Imperial Coll Sci Technol & Med, Dept Space & Atmospher Phys, London, England. [Petrinec, S. M.] Lockheed Martin Adv Technol Ctr, Space Phys Lab, Palo Alto, CA USA. [Reme, H.] Ctr Etud Spatiale Rayonnements, Toulouse, France. [Russell, C. T.] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. [Zheng, Y.] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. RP Le, G (reprint author), NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. EM guan.le@nasa.gov RI Le, Guan/C-9524-2012; Zheng, Yihua/D-7368-2012; Slavin, James/H-3170-2012; Pfaff, Robert/F-5703-2012 OI Le, Guan/0000-0002-9504-5214; Slavin, James/0000-0002-9206-724X; Pfaff, Robert/0000-0002-4881-9715 NR 54 TC 10 Z9 10 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 12 PY 2008 VL 113 IS A1 AR A01205 DI 10.1029/2007JA012377 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251IK UT WOS:000252366400002 ER PT J AU Poole, TS Breeveld, AA Page, MJ Landsman, W Holland, ST Roming, P Kuin, NPM Brown, PJ Gronwall, C Hunsberger, S Koch, S Mason, KO Schady, P Vanden Berk, D Blustin, AJ Boyd, P Broos, P Carter, M Chester, MM Cucchiara, A Hancock, B Huckle, H Immler, S Ivanushkina, M Kennedy, T Marshall, F Morgan, A Pandey, SB de Pasquale, M Smith, PJ Still, M AF Poole, T. S. Breeveld, A. A. Page, M. J. Landsman, W. Holland, S. T. Roming, P. Kuin, N. P. M. Brown, P. J. Gronwall, C. Hunsberger, S. Koch, S. Mason, K. O. Schady, P. Vanden Berk, D. Blustin, A. J. Boyd, P. Broos, P. Carter, M. Chester, M. M. Cucchiara, A. Hancock, B. Huckle, H. Immler, S. Ivanushkina, M. Kennedy, T. Marshall, F. Morgan, A. Pandey, S. B. de Pasquale, M. Smith, P. J. Still, M. TI Photometric calibration of the Swift ultraviolet/optical telescope SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE instrumentation : photometers; techniques : photometric; ultraviolet : general ID PHOTON-COUNTING DETECTORS; STANDARD STARS; ABSOLUTE FLUX; MISSION; SYSTEMS; UBV AB We present the photometric calibration of the Swift Ultraviolet/Optical Telescope (UVOT) which includes: optimum photometric and background apertures, effective area curves, colour transformations, conversion factors for count rates to flux and the photometric zero-points (which are accurate to better than 4 per cent) for each of the seven UVOT broad-band filters. The calibration was performed with observations of standard stars and standard star fields that represent a wide range of spectral star types. The calibration results include the position-dependent uniformity, and instrument response over the 1600-8000 angstrom operational range. Because the UVOT is a photon-counting instrument, we also discuss the effect of coincidence loss on the calibration results. We provide practical guidelines for using the calibration in UVOT data analysis. The results presented here supersede previous calibration results. C1 [Poole, T. S.; Breeveld, A. A.; Page, M. J.; Kuin, N. P. M.; Mason, K. O.; Schady, P.; Blustin, A. J.; Carter, M.; Hancock, B.; Huckle, H.; Kennedy, T.; Pandey, S. B.; de Pasquale, M.; Smith, P. J.] UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. [Roming, P.; Brown, P. J.; Gronwall, C.; Hunsberger, S.; Koch, S.; Vanden Berk, D.; Broos, P.; Chester, M. M.; Cucchiara, A.; Ivanushkina, M.; Morgan, A.] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. [Holland, S. T.] NASA, Goddard Space Flight Ctr, Ctr Res & Explorat Space Sci & Technol, Greenbelt, MD 20771 USA. [Holland, S. T.] Univ Space Res Assoc, Columbia, MD 21044 USA. [Mason, K. O.] Polaris House, Sci & Technol Facil Council, Swindon SN2 1SZ, Wilts, England. RP Poole, TS (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM aab@mssl.ucl.ac.uk RI Boyd, Patricia/D-3274-2012 NR 42 TC 421 Z9 421 U1 1 U2 7 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 11 PY 2008 VL 383 IS 2 BP 627 EP 645 DI 10.1111/j.1365-2966.2007.12563.x PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 247ZV UT WOS:000252122000019 ER PT J AU Bagagli, R Baldini, L Bellazzini, R Barblellini, G Belli, F Borden, T Brez, A Brigida, M Caliandro, GA Cecchi, C Cohen-Tanugi, J De Angelis, A Drell, P Favuzzi, C Fusco, P Gargano, F Germani, S Giglietto, N Giordano, F Goodman, J Himel, T Hirayarna, M Johnson, RP Katagiri, H Kataoka, J Kawai, N Kroeger, W Ku, J Kuss, M Latronico, L Longo, F Loparco, F Lubrano, P Marangelli, B Marcucci, F Marchetti, M Massai, MM Mazziotta, MN Minori, M Minuti, M Mirizzi, N Mongelli, M Monte, C Morselli, A Nelson, D Nordby, M Omodei, N Pepe, M Pesce-Rollins, M Raino, S Rando, R Razzano, M Rich, D Scolieri, G Sgro, C Spandre, G Spinelli, P Sugizaki, M Takahashi, H Tenze, A Young, C AF Bagagli, R. Baldini, L. Bellazzini, R. Barblellini, G. Belli, F. Borden, T. Brez, A. Brigida, M. Caliandro, G. A. Cecchi, C. Cohen-Tanugi, J. De Angelis, A. Drell, P. Favuzzi, C. Fusco, P. Gargano, F. Germani, S. Giglietto, N. Giordano, F. Goodman, J. Himel, T. Hirayarna, M. Johnson, R. P. Katagiri, H. Kataoka, J. Kawai, N. Kroeger, W. Ku, J. Kuss, M. Latronico, L. Longo, F. Loparco, F. Lubrano, P. Marangelli, B. Marcucci, F. Marchetti, M. Massai, M. M. Mazziotta, M. N. Minori, M. Minuti, M. Mirizzi, N. Mongelli, M. Monte, C. Morselli, A. Nelson, D. Nordby, M. Omodei, N. Pepe, M. Pesce-Rollins, M. Raino, S. Rando, R. Razzano, M. Rich, D. Scolieri, G. Sgro, C. Spandre, G. Spinelli, P. Sugizaki, M. Takahashi, H. Tenze, A. Young, C. TI Environmental tests of the flight GLAST LAT tracker towers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE gamma-ray; telescope; tracking; silicon strip detector; environmental tests ID SPACE; TELESCOPE AB The Gamma-ray Large Area Space telescope (GLAST) is a gamma-ray satellite scheduled for launch in 2008. Before the assembly of the Tracker subsystem of the Large Area Telescope (LAT) science instrument of GLAST, every component (tray) and module (tower) has been subjected to extensive ground testing required to ensure successful launch and on-orbit operation. This paper describes the sequence and results of the environmental tests performed on an engineering model and all the flight hardware of the GLAST LAT Tracker. Environmental tests include vibration testing, thermal cycles and thermal-vacuum cycles of every tray and tower as well as the verification of their electrical performance. (C) 2007 Elsevier B.V. All rights reserved. C1 [Brigida, M.; Caliandro, G. A.; Favuzzi, C.; Fusco, P.; Gargano, F.; Giglietto, N.; Giordano, F.; Loparco, F.; Marangelli, B.; Mazziotta, M. N.; Mirizzi, N.; Mongelli, M.; Monte, C.; Raino, S.; Spinelli, P.] Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy. [Brigida, M.; Caliandro, G. A.; Favuzzi, C.; Fusco, P.; Giglietto, N.; Giordano, F.; Loparco, F.; Marangelli, B.; Mirizzi, N.; Monte, C.; Raino, S.; Spinelli, P.] Univ Politecn Bari, Dipartimento Interateneo Fis, I-70126 Bari, Italy. [Rando, R.] Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. [Rando, R.] Univ Padua, Dipartimento Fis, I-35131 Padua, Italy. [Cecchi, C.; Germani, S.; Lubrano, P.; Marcucci, F.; Pepe, M.; Scolieri, G.] Ist Nazl Fis Nucl, Sez Perugia, I-06123 Perugia, Italy. [Cecchi, C.; Marcucci, F.] Univ Perugia, Dipartimento Fis, I-06123 Perugia, Italy. [Bagagli, R.; Baldini, L.; Bellazzini, R.; Brez, A.; Kuss, M.; Latronico, L.; Massai, M. M.; Minuti, M.; Omodei, N.; Pesce-Rollins, M.; Spandre, G.; Tenze, A.] Ist Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, Italy. [Massai, M. M.; Razzano, M.] Univ Pisa, Dipartimento Fis E Fermi, I-56127 Pisa, Italy. [Sgro, C.] Scuola Normale Super Pisa, I-56126 Pisa, Italy. [Belli, F.; Marchetti, M.; Minori, M.; Morselli, A.] Ist Nazl Fis Nucl, Sez Roma Tor Vergata, I-00133 Rome, Italy. [Barblellini, G.; Longo, F.] Ist Nazl Fis Nucl, Sez Trieste, I-34012 Trieste, Italy. [Barblellini, G.; Longo, F.] Univ Trieste, Dipartimento Fis, I-34012 Trieste, Italy. [De Angelis, A.] Ist Nazl Fis Nucl, Grp Coll Udine, I-33100 Udine, Italy. [De Angelis, A.] Univ Udine, Dipartimento Fis, I-33100 Udine, Italy. [Johnson, R. P.] Univ Calif Santa Cruz, Inst Particle Phys, Santa Cruz, CA 95064 USA. [Borden, T.; Cohen-Tanugi, J.; Drell, P.; Goodman, J.; Himel, T.; Kroeger, W.; Nelson, D.; Nordby, M.; Young, C.] SLAC, Menlo Pk, CA 94025 USA. [Hirayarna, M.] CRESST, Greenbelt, MD 20771 USA. [Hirayarna, M.] NASA, Goddard Space Flight Ctr, Astroparticle Phys Lab, Greenbelt, MD 20771 USA. [Hirayarna, M.] Univ Maryland, Dept Phys, Baltimore, MD 21250 USA. [Katagiri, H.; Takahashi, H.] Hiroshima Univ, Higashihiroshima 7398526, Japan. [Kataoka, J.; Kawai, N.] Tokyo Inst Technol, Tokyo 1528551, Japan. RP Mazziotta, MN (reprint author), Ist Nazl Fis Nucl, Sez Bari, Via E Orabona 4, I-70126 Bari, Italy. EM mazziotta@ba.infn.it; silvia.raino@ba.infn.it RI Baldini, Luca/E-5396-2012; lubrano, pasquale/F-7269-2012; Morselli, Aldo/G-6769-2011; Kuss, Michael/H-8959-2012; giglietto, nicola/I-8951-2012; Rando, Riccardo/M-7179-2013; Gargano, Fabio/O-8934-2015; Loparco, Francesco/O-8847-2015; Mazziotta, Mario /O-8867-2015; Sgro, Carmelo/K-3395-2016; OI De Angelis, Alessandro/0000-0002-3288-2517; Omodei, Nicola/0000-0002-5448-7577; Pesce-Rollins, Melissa/0000-0003-1790-8018; Baldini, Luca/0000-0002-9785-7726; Sgro', Carmelo/0000-0001-5676-6214; lubrano, pasquale/0000-0003-0221-4806; SPINELLI, Paolo/0000-0001-6688-8864; Morselli, Aldo/0000-0002-7704-9553; giglietto, nicola/0000-0002-9021-2888; Gargano, Fabio/0000-0002-5055-6395; Loparco, Francesco/0000-0002-1173-5673; Mazziotta, Mario /0000-0001-9325-4672; Rando, Riccardo/0000-0001-6992-818X; Giordano, Francesco/0000-0002-8651-2394 NR 40 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JAN 11 PY 2008 VL 584 IS 2-3 BP 358 EP 373 DI 10.1016/j.nima.2007.10.035 PG 16 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 261LZ UT WOS:000253081800013 ER PT J AU Balasubramanian, K AF Balasubramanian, Kunjithapatham TI Band-limited image plane masks for the Terrestrial Planet Finder coronagraph: materials and designs for broadband performance SO APPLIED OPTICS LA English DT Article ID FILMS AB Coronagraphs for detection and characterization of exosolar earthlike planets require accurate masks with broadband performance in the visible and near infrared spectrum. Design and fabrication of image plane masks capable of suppressing broadband starlight to 10(-10) level contrast presents technical challenges. We discuss basic approaches, material choices, designs, and fabrication options for image plane masks with particular focus on material properties to obtain adequate spectral performance. Based on theoretical analysis, we show that metals such as Pt and Ni, and alloys such as Inconel, may be employed as promising mask materials that can meet broadband performance requirements. (c) 2008 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Balasubramanian, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kbala@jpl.nasa.gov NR 19 TC 8 Z9 8 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JAN 10 PY 2008 VL 47 IS 2 BP 116 EP 125 DI 10.1364/AO.47.000116 PG 10 WC Optics SC Optics GA 257XR UT WOS:000252833100004 PM 18188191 ER PT J AU Rogers, RB Peter, K Lagerlof, D AF Rogers, Richard B. Peter, K. Lagerlof, D. TI Crystallography of ordered colloids using optical microscopy. 1. Parallel-beam technique SO APPLIED OPTICS LA English DT Article ID STACKING DISORDER; PHASE-TRANSITION; CRYSTALS; SPHERES; CRYSTALLIZATION; STATE AB A technique is described for determining the reciprocal lattice basis vectors of randomly oriented colloidal crystals from optical Fourier transform images using a parallel incident beam. This approach is demonstrated by comparing information gathered using this technique with results from real-space images for a single colloidal crystal grain with a random hexagonal close-packed structure. The reciprocal space and available real-space results agreed to within experimental error. The complete set of reciprocal lattice basis vectors was determined using the proposed technique in contrast to the partial lattice information available from real-space images. This technique appears to be generally capable of measuring lattice parameters to within 1% and orientation to better than 1 degrees. (c) 2008 Optical Society of America. C1 [Rogers, Richard B.; Peter, K.; Lagerlof, D.] Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. [Rogers, Richard B.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Rogers, RB (reprint author), Case Western Reserve Univ, Dept Mat Sci & Engn, 10900 Euclid Ave, Cleveland, OH 44106 USA. EM richard.b.rogers@nasa.gov NR 33 TC 3 Z9 3 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JAN 10 PY 2008 VL 47 IS 2 BP 284 EP 295 DI 10.1364/AO.47.000284 PG 12 WC Optics SC Optics GA 257XR UT WOS:000252833100024 PM 18188211 ER PT J AU Gaspar, A Su, KYL Rieke, GH Balog, Z Kamp, I Martinez-Galarza, JR Stapelfeldt, K AF Gaspar, A. Su, K. Y. L. Rieke, G. H. Balog, Z. Kamp, I. Martinez-Galarza, J. R. Stapelfeldt, K. TI Modeling the infrared bow shock at delta Velorum: Implications for studies of debris disks and lambda Bootis stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : ISM; ISM : kinematics and dynamics; radiation mechanisms : thermal; stars : evolution; stars : imaging; stars : individual (HD 74956, delta Velorum); shock waves ID MULTIBAND IMAGING PHOTOMETER; ACCRETION DIFFUSION-MODEL; MAIN-SEQUENCE STARS; INTERSTELLAR CLOUDS; ABSOLUTE CALIBRATION; NEARBY STARS; LOCAL BUBBLE; SPITZER; DUST; SPECTROSCOPY AB We have discovered a bow shock shaped mid-infrared excess region in front of delta Velorum using 24 mu m observations obtained with the Multiband Imaging Photometer for Spitzer (MIPS). Although the bow shock morphology was only detected in the 24 mu m observations, its excess was also resolved at 70 mu m. We show that the stellar heating of an ambient interstellar medium (ISM) cloud can produce the measured flux. Since delta Velorum was classified as a debris disk star previously, our discovery may call into question the same classification of other stars. We model the interaction of the star and ISM, producing images that show the same geometry and surface brightness as is observed. The modeled ISM is similar to 15 times overdense relative to the average Local Bubble value, which is surprising considering the close proximity (24 pc) of delta Velorum. The abundance anomalies of lambda Bootis stars have been previously explained as arising from the same type of interaction of stars with the ISM. Low-resolution optical spectra of delta Velorum show that it does not belong to this stellar class. The star therefore is an interesting testbed for the ISM accretion theory of the lambda Bootis phenomenon. C1 [Gaspar, A.; Su, K. Y. L.; Rieke, G. H.; Balog, Z.] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. [Kamp, I.] STScI, ESA, Space Telescope Sci Div, Baltimore, MD 21218 USA. [Martinez-Galarza, J. R.] Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands. [Stapelfeldt, K.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaspar, A (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM agaspar@as.arizona.edu RI Stapelfeldt, Karl/D-2721-2012 NR 48 TC 24 Z9 24 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 2008 VL 672 IS 2 BP 974 EP 983 DI 10.1086/523299 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RG UT WOS:000253454100020 ER PT J AU Valencic, LA Smith, RK AF Valencic, Lynne A. Smith, Randall K. TI An analysis of the dust halo and extinction toward X Persei SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction ID DIFFUSE INTERSTELLAR-MEDIUM; FAR-ULTRAVIOLET EXTINCTION; INFRARED-EMISSION FEATURES; SMALL-MAGELLANIC-CLOUD; LINE-OF-SIGHT; TO-GAS RATIO; RAY HALOS; HD 24534; ABUNDANCE CONSTRAINTS; REFLECTION NEBULAE AB Interstellar dust grain models are not sufficiently constrained by UV extinction curves to allow researchers to distinguish between them. By testing grain models in the X-ray regime and applying elemental abundance constraints, we show to what extent the models can reproduce the observables in these regimes and whether they are capable of doing so while respecting the abundance limits. We tested the MRN and WD grain models using the UV extinction and X-ray halos along the line of sight toward X Per. Both models provide reasonable fits to the UV extinction and X-ray halos but cannot do so while respecting the elemental abundance constraints. Furthermore, the abundances and N-H required to reproduce the observables in these two regimes are not consistent with each other, reflecting the fact that X-ray regime constraints were not taken into account when the models' grain size distributions were constructed, and thus the models are incomplete. Both MRN and WD underestimate the hydrogen column density N-H when the standard model parameters for R-V = 3.1 are used. The problem is mitigated when model parameters derived from fitting the UV extinction are used, but this does not necessarily lead to agreement between the two regimes. C1 [Valencic, Lynne A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Smith, Randall K.] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Valencic, LA (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. EM valencic@milkyway.gsfc.nasa.gov; rsmith@milkyway.gsfc.nasa.gov NR 93 TC 8 Z9 8 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 2008 VL 672 IS 2 BP 984 EP 995 DI 10.1086/523700 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RG UT WOS:000253454100021 ER PT J AU Padgett, DL Rebull, LM Stapelfeldt, KR Chapman, NL Lai, SP Mundy, LG Evans, NJ Brooke, TY Cieza, LA Spiesman, WJ Noriega-Crespo, A McCabe, CE Allen, LE Blake, GA Harvey, PM Huard, TL Jorgensen, JK Koerner, DW Myers, PC Sargent, AI Teuben, P van Dishoeck, EF Wahhaj, Z Young, KE AF Padgett, Deborah L. Rebull, Luisa M. Stapelfeldt, Karl R. Chapman, Nicholas L. Lai, Shih-Ping Mundy, Lee G. Evans, Neal J., II Brooke, Timothy Y. Cieza, Lucas A. Spiesman, William J. Noriega-Crespo, Alberto McCabe, Caer-Eve Allen, Lori E. Blake, Geoffrey A. Harvey, Paul M. Huard, Tracy L. Jorgensen, Jes K. Koerner, David W. Myers, Philip C. Sargent, Annelia I. Teuben, Peter van Dishoeck, Ewine F. Wahhaj, Zahed Young, Kaisa E. TI The Spitzer c2d survey of large, nearby, interstellar clouds. VII. Ophiuchus observed with MIPS SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; ISM : clouds; stars : formation ID YOUNG STELLAR OBJECTS; SPECTRAL ENERGY-DISTRIBUTIONS; SPACE-TELESCOPE OBSERVATIONS; BROWN DWARF CANDIDATES; INITIAL MASS FUNCTION; STAR-FORMING REGIONS; MAIN-SEQUENCE STARS; RHO-OPHIUCHI; DARK-CLOUD; MOLECULAR CLOUD AB We present maps of 14.4 deg(2) of the Ophiuchus dark clouds observed by the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer ( MIPS). These high-quality maps depict both numerous point sources and extended dust emission within the star-forming and non-star-forming portions of these clouds. Using PSF-fitting photometry, we detect 5779 sources at 24 mu m and 81 sources at 70 mu m at the 10 sigma level of significance. Three hundred twenty-three candidate young stellar objects ( YSOs) were identified according to their positions on the MIPS/2MASS K versus K - [24] color-magnitude diagrams, as compared to 24 mu m detections in the SWIRE extragalactic survey. We find that more than half of the YSO candidates, and almost all those with protostellar Class I spectral energy distributions, are confined to the known cluster and aggregates. C1 [Padgett, Deborah L.; Rebull, Luisa M.; Brooke, Timothy Y.; Noriega-Crespo, Alberto; McCabe, Caer-Eve] CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. [Stapelfeldt, Karl R.; McCabe, Caer-Eve] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Chapman, Nicholas L.; Lai, Shih-Ping; Mundy, Lee G.] Univ Maryland, Dept Astron, College Pk, MD 20742 USA. [Lai, Shih-Ping] Natl Tsing Hua Univ, Dept Phys, Hsinchu 30043, Taiwan. [Lai, Shih-Ping] Natl Tsing Hua Univ, Dept Astron, Hsinchu 30043, Taiwan. [Lai, Shih-Ping] Acad Sinica, Inst Astron & Astrophys, Taipei 106, Taiwan. [Evans, Neal J., II; Cieza, Lucas A.; Spiesman, William J.; Harvey, Paul M.; Young, Kaisa E.] Univ Texas Austin, Dept Astron, Austin, TX 78712 USA. [Allen, Lori E.; Myers, Philip C.] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. [Blake, Geoffrey A.] CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. [Koerner, David W.; Wahhaj, Zahed] No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. [van Dishoeck, Ewine F.] Leiden Univ, Leiden Observ, NL-2300 RA Leiden, Netherlands. [Sargent, Annelia I.] CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. RP Padgett, DL (reprint author), CALTECH, Spitzer Sci Ctr, MC 220-6, Pasadena, CA 91125 USA. EM dlp@ipac.caltech.edu RI Stapelfeldt, Karl/D-2721-2012; OI Rebull, Luisa/0000-0001-6381-515X NR 66 TC 64 Z9 64 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 2008 VL 672 IS 2 BP 1013 EP 1037 DI 10.1086/523883 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RG UT WOS:000253454100024 ER PT J AU Schulz, NS Kallman, TE Galloway, DK Brandt, WN AF Schulz, N. S. Kallman, T. E. Galloway, D. K. Brandt, W. N. TI The variable warm absorber in Circinus X-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (Cir X-1); stars : neutron; techniques : spectroscopic; X-rays : stars ID X-RAY SPECTROSCOPY; ACCRETION DISK CORONA; TRANSMISSION GRATING SPECTROMETER; ACTIVE GALACTIC NUCLEI; HELIUM-LIKE IONS; BLACK-HOLES; INTERSTELLAR-MEDIUM; PHOTOIONIZED PLASMA; ZERO PHASE; CIR X-1 AB We observed Circinus X-1 twice during a newly reached low-flux phase near zero orbital phase using the High-Energy Transmission Grating Spectrometer (HETGS) onboard Chandra. In both observations the source did not show the P Cygni lines we observed during the high-flux phases of the source in 2000 and 2001. During the prezero phase the source did not exhibit significant variability but did exhibit an emission-line spectrum rich in H-and He-like lines from high-Z elements such as Si, S, Ar, and Ca. The light curve in the postdip observation showed quiescent and flaring episodes. Only in these flaring episodes was the source luminosity significantly higher than observed during the prezero phase. We analyzed all high-resolution X-ray spectra by fitting photoionization and absorption models from the most recent version of the XSTAR code. The prezero-phase spectrum could be fully modeled with a very hot photoionized plasma with an ionization parameter of log xi = 3.0, down from log xi = 4.0 in the high-flux state. The ionization balances we measure from the spectra during the postzero-phase episodes are significantly different. Both episodes feature absorbers with variable high columns, ionization parameters, and luminosity. While cold absorption remains at levels quite similar to that observed in previous years, the new observations show unprecedented levels of variable warm absorption. The line emissivities also indicate that the observed low source luminosity is inconsistent with a static hot accretion disk corona (ADC), an effect that seems common to other near-edge-on ADC sources as well. We conclude that unless there exists some means of coronal heating other than X-rays, the true source luminosity is likely much higher, and we observe obscuration in analogy to the extragalactic Seyfert 2 sources. We discuss possible consequences and relate cold, lukewarm, warm, and hot absorbers to dynamic accretion scenarios. C1 [Schulz, N. S.] MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. [Kallman, T. E.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Galloway, D. K.] Univ Melbourne, Sch Phys, Parkville, Vic 3010, Australia. [Brandt, W. N.] Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. RP Schulz, NS (reprint author), MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Brandt, William/N-2844-2015; OI Brandt, William/0000-0002-0167-2453; Galloway, Duncan/0000-0002-6558-5121 NR 81 TC 16 Z9 16 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 10 PY 2008 VL 672 IS 2 BP 1091 EP 1102 DI 10.1086/523809 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 266RG UT WOS:000253454100030 ER PT J AU Eriksen, HK Dickinson, C Jewell, JB Banday, AJ Gorski, KM Lawrence, CR AF Eriksen, H. K. Dickinson, C. Jewell, J. B. Banday, A. J. Gorski, K. M. Lawrence, C. R. TI The joint large-scale foreground - CMB posteriors of the 3 year WMAP data SO ASTROPHYSICAL JOURNAL LETTERS LA English DT Article DE cosmic microwave background; cosmology : observations; methods : numerical ID MICROWAVE-ANISOTROPY-PROBE; BAYESIAN-ANALYSIS; EMISSION; FREQUENCIES; SPECTRA; MAPS AB Using a Gibbs sampling algorithm for joint CMB estimation and component separation, we compute the large-scale CMB and foreground posteriors of the 3 yr WMAP temperature data. Our parametric data model includes the cosmological CMB signal and instrumental noise, a single power law foreground component with free amplitude and spectral index for each pixel, a thermal dust template with a single free overall amplitude, and free monopoles and dipoles at each frequency. This simple model yields a good fit to the data over the full frequency range from 23 to 94 GHz. We obtain a new estimate of the CMB sky signal and power spectrum, and a new foreground model, including a measurement of the effective spectral index over the high-latitude sky. A noteworthy result in this respect is the detection of a common spurious offset in all frequency bands of similar to-13 mu K, as well as a dipole in the V-band data. Correcting for these is essential when determining the effective spectral index of the foregrounds. Fortunately, the CMB power spectrum is not significantly affected by these issues, as our new spectrum is in excellent agreement with that published by the WMAP team. The corresponding cosmological parameters are also virtually unchanged. C1 [Eriksen, H. K.] Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. [Eriksen, H. K.] Univ Oslo, Ctr Math Appl, N-0316 Oslo, Norway. [Dickinson, C.; Jewell, J. B.; Gorski, K. M.; Lawrence, C. R.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Banday, A. J.] Max Planck Inst Astrophys, D-85741 Munich, Germany. [Gorski, K. M.] Warsaw Univ Observatory, PL-00478 Warsaw, Poland. RP Eriksen, HK (reprint author), Univ Oslo, Inst Theoret Astrophys, POB 1029 Blindern, N-0315 Oslo, Norway. EM h.k.k.eriksen@astro.uio.no NR 20 TC 22 Z9 22 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 2041-8205 EI 2041-8213 J9 ASTROPHYS J LETT JI Astrophys. J. Lett. PD JAN 10 PY 2008 VL 672 IS 2 BP L87 EP L90 DI 10.1086/526545 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 291YC UT WOS:000255232300001 ER PT J AU Forbes, JM Lemoine, FG Bruinsma, SL Smith, MD Zhang, XL AF Forbes, Jeffrey M. Lemoine, Frank G. Bruinsma, Sean L. Smith, Michael D. Zhang, Xiaoli TI Solar flux variability of Mars' exosphere densities and temperatures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID UPPER-ATMOSPHERE; CYCLE VARIATION; THERMOSPHERE MODEL; MGS ACCELEROMETER; GLOBAL STRUCTURE; EARTH; ROTATION; VENUS; TIDES; WINDS AB Using densities derived from precise orbit determination of the Mars Global Surveyor (MGS) spacecraft from 1999 to mid-2005, the response of Mars' exosphere to long-term solar change is established and compared to that of Earth and Venus. At Mars, exosphere temperatures ( weighted towards high-latitude Southern Hemisphere daytime conditions) change only 36-50% as much as those at Earth as solar activity increases from solar minimum to solar maximum, whereas the response at Venus is one-fifth that at Mars. General circulation models suggest that this difference may be strongly influenced by adiabatic cooling associated with the thermosphere general circulation. However, other processes such as differences in CO2 cooling rates may also be playing a role. C1 [Forbes, Jeffrey M.; Zhang, Xiaoli] Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. [Lemoine, Frank G.; Smith, Michael D.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Bruinsma, Sean L.] Ctr Natl Etud Spatiales, Dept Terrestrial & Planetary Geodesy, F-31401 Toulouse, France. RP Forbes, JM (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. EM forbes@colorado.edu; frank.lemoine@gsfc.nasa.gov; sean.bruinsma@cnes.fr; michael.d.smith@nasa.gov; xiaoli.zhang@colorado.edu RI Smith, Michael/C-8875-2012; Lemoine, Frank/D-1215-2013; OI FORBES, JEFFREY/0000-0001-6937-0796 NR 23 TC 31 Z9 31 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 10 PY 2008 VL 35 IS 1 AR L01201 DI 10.1029/2007GL031904 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 251GS UT WOS:000252361900001 ER PT J AU Reichle, RH Crow, WT Koster, RD Sharif, HO Mahanama, SPP AF Reichle, R. H. Crow, W. T. Koster, R. D. Sharif, H. O. Mahanama, S. P. P. TI Contribution of soil moisture retrievals to land data assimilation products SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SYSTEM SIMULATION EXPERIMENT; AMSR-E AB Satellite measurements (retrievals) of surface soil moisture are subject to errors and cannot provide complete space-time coverage. Data assimilation systems merge available retrievals with information from land surface models and antecedent meteorological data, information that is spatio-temporally complete but likewise uncertain. For the design of new satellite missions it is critical to understand just how uncertain retrievals can be and still be useful. Here, we present a synthetic data assimilation experiment that determines the contribution of retrievals to the skill of land assimilation products (soil moisture and evapotranspiration) as a function of retrieval and land model skill. As expected, the skill of the assimilation products increases with the skill of the model and that of the retrievals. The skill of the soil moisture assimilation products always exceeds that of the model acting alone; even retrievals of low quality contribute information to the assimilation product, particularly if model skill is modest. C1 [Reichle, R. H.; Koster, R. D.; Mahanama, S. P. P.] NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. [Reichle, R. H.; Mahanama, S. P. P.] Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. [Crow, W. T.] USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. [Sharif, H. O.] Univ Texas San Antonio, Dept Civil Engn, San Antonio, TX 78249 USA. RP Reichle, RH (reprint author), NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Code 610-1,Greenbelt Rd, Greenbelt, MD 20771 USA. EM rolf.reichle@nasa.gov RI Sharif, Hatim/E-4426-2010; Reichle, Rolf/E-1419-2012; Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 17 TC 31 Z9 31 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 10 PY 2008 VL 35 IS 1 AR L01404 DI 10.1029/2007GL031986 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 251GS UT WOS:000252361900003 ER PT J AU Harris, R Wang, ZJ Liu, Y AF Harris, Rob Wang, Z. J. Liu, Yen TI Efficient quadrature-free high-order spectral volume method on unstructured grids: Theory and 2D implementation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE spectral volume method; enter equations; unstructured grid; hyperbolic conservation laws ID FINITE-ELEMENT-METHOD; ESSENTIALLY NONOSCILLATORY SCHEMES; DISCONTINUOUS GALERKIN METHOD; ONE-DIMENSIONAL SYSTEMS; CONSERVATION-LAWS; EXTENSION; FLOW; EQUATIONS; MESHES AB An efficient implementation of the high-order spectral volume (SV) method is presented for multi-dimensional conservation laws on unstructured grids. In the SV method, each simplex cell is called a spectral volume (SV), and the SV is further subdivided into polygonal (2D), or polyhedral (3D) control volumes (CVs) to support high-order data reconstructions. In the traditional implementation, Gauss quadrature formulas are used to approximate the flux integrals on all faces. In the new approach, a nodal set is selected and used to reconstruct a high-order polynomial approximation for the flux vector, and then the flux integrals on the internal faces are computed analytically, without the need for Gauss quadrature formulas. This gives a significant advantage over the traditional SV method in efficiency and ease of implementation. For SV interfaces, a quadrature-free approach is compared with the Gauss quadrature approach to further evaluate the accuracy and efficiency. A simplified treatment of curved boundaries is also presented that avoids the need to store a separate reconstruction for each boundary cell. Fundamental properties of the new SV implementation are studied and high-order accuracy is demonstrated for linear and non-linear advection equations, and the Euler equations. Several well known inviscid flow test cases are utilized to show the effectiveness of the simplified curved boundary representation. (C) 2007 Elsevier Inc. All rights reserved. C1 [Harris, Rob; Wang, Z. J.] Iowa State Univ, Dept Aerosp Engn, Ames, IA 50011 USA. [Liu, Yen] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Harris, R (reprint author), Iowa State Univ, Dept Aerosp Engn, 2271 Howe Hall, Ames, IA 50011 USA. EM rharris@iastate.edu; zjw@iastate.edu; liu@nas.nasa.gov RI Wang, Z.J./A-9628-2010 OI Wang, Z.J./0000-0002-6203-6303 NR 39 TC 16 Z9 16 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD JAN 10 PY 2008 VL 227 IS 3 BP 1620 EP 1642 DI 10.1016/j.jcp.2007.09.012 PG 23 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 258IC UT WOS:000252860600003 ER PT J AU Santos-Costa, D Bolton, SJ Thorne, M Miyoshi, Y Levin, SM AF Santos-Costa, D. Bolton, S. J. Thorne, M. Miyoshi, Y. Levin, S. M. TI Investigating the origins of the Jovian decimetric emission's variability SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID JUPITERS SYNCHROTRON-RADIATION; LONG-TERM VARIATIONS; EUV FLUX MODEL; RADIO-EMISSION; ENERGETIC ELECTRONS; MAGNETIC-FIELD; COMET SL-9; 22 CM; NONTHERMAL RADIATION; 3-D RECONSTRUCTION AB The long-term variability of the Jovian radiation observed at 13-cm wavelength over 30 years is investigated using a physical model of the radiation belts. The model enables us to quantify the effect of the geometric parameter DE on the synchrotron emission. When a full Jupiter rotation is taken into account in the computations, the variability of the total radio flux with DE is only similar or equal to 1% of that measured. Such a dependence is not detectable. In contrast, radio fluctuations observed at a central meridian longitude (CML) and caused by DE changes can be very important, up to 10% of that measured. This strong dependence of the total radio flux on the geometric factor can result in difficulties for examining the origins of the Jovian synchrotron emission's fluctuations during periods where times of observation are not covering large CML range values. The numerical computations reveal that the variability either of the populations injected near the outer boundary of our simulations (Io's orbit) or the inward radial transport can, independently or in combined action, conduct variability in the decimetric emission. The theoretical fluctuations required in our computations for reproducing the radio measurements do not confirm any direct correlation between the long-term changes in the radio data and the radial transport driven by solar wind conditions or solar radio fluxes. Nevertheless, a linear relationship between the total radio flux and solar wind ram pressure for the period of 1970 to 2002 is established. The maximum correlation is reached when the P-sw data are shifted by similar or equal to 2.7 years prior to the radio observations. Using this time-lag in the computations, the simulation results show that ( Psw) g can be associated with the variations of the particle injections and the radial transport. The correlation coefficient, associated with the fit between radio data and simulated radio flux densities, is 0.59 for the period of 1971 - 2002, 0.93 for the period of 1971 - 1972, and 0.83 for the periods of 1975 - 1989 and 1992 - 1995. The index g is set to 0.35 when only particle injections are fluctuating with time, to 0.50 when temporal variations are driving the radial transport, and to 0.15 - 0.20 when the particles injected in the inner magnetosphere and their transport are simultaneously following the variations of the solar wind ram pressure. The model suggests that the solar wind ram pressure fluctuations can be related to variations of the Jovian decimetric emission on timescales of months, particularly to the enhancements in total radio flux observed in 1987, 1988, 1990 and 1994. Our results thus support the idea that the increase in radio emission in July 1994 was due to the impact of Comet Shoemaker-Levy 9 into Jupiter, in addition to the response of the Jovian magnetosphere to steep changes in solar wind conditions. The divergence between observations and simulations indicates that mechanisms other than those discussed in the modeling must govern the radiation belts dynamics for the periods of 1972 - 1975 and 1996 - 2002. C1 [Santos-Costa, D.; Bolton, S. J.] SwRI, Dept Space Sci, San Antonio, TX 78238 USA. [Thorne, M.] Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA. [Miyoshi, Y.] Nagoya Univ, Solar Terrestrial Environm Lab, Nagoya, Aichi 4648601, Japan. [Levin, S. M.] Jet Propuls Lab, Pasadena, CA 91109 USA. RP Santos-Costa, D (reprint author), SwRI, Dept Space Sci, San Antonio, TX 78238 USA. EM dsantoscosta@swri.edu; sbolton@swri.edu; rmt@atmos.ucla.eu; miyoshi@stelab.nagoya-u.ac.jp; steven.levin@jpl.nasa.gov RI Miyoshi, Yoshizumi/B-5834-2015 OI Miyoshi, Yoshizumi/0000-0001-7998-1240 NR 85 TC 7 Z9 7 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 10 PY 2008 VL 113 IS A1 AR A01204 DI 10.1029/2007JA012396 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251II UT WOS:000252366200002 ER PT J AU Weidenspointner, G Skinner, G Jean, P Knodlseder, J von Ballmoos, P Bignami, G Diehl, R Strong, AW Cordier, B Schanne, S Winkler, C AF Weidenspointner, Georg Skinner, Gerry Jean, Pierre Knoedlseder, Juergen von Ballmoos, Peter Bignami, Giovanni Diehl, Roland Strong, Andrew W. Cordier, Bertrand Schanne, Stephane Winkler, Christoph TI An asymmetric distribution of positrons in the Galactic disk revealed by gamma-rays SO NATURE LA English DT Article ID ANNIHILATION RADIATION; SKY DISTRIBUTION; INNER GALAXY; BLACK-HOLE; MILKY-WAY; EMISSION; AL-26; SEARCH AB Gamma- ray line radiation at 511 keV is the signature of electron positron annihilation. Such radiation has been known for 30 years to come from the general direction of the Galactic Centre(1), but the origin of the positrons has remained a mystery. Stellar nucleosynthesis(2-4), accreting compact objects(5-8), and even the annihilation of exotic dark- matter particles(9) have all been suggested. Here we report a distinct asymmetry in the 511- keV line emission coming from the inner Galactic disk ( similar to 10-50 degrees from the Galactic Centre). This asymmetry resembles an asymmetry in the distribution of low mass X- ray binaries with strong emission at photon energies >20 keV ('hard' LMXBs), indicating that they may be the dominant origin of the positrons. Although it had long been suspected that electron - positron pair plasmas may exist in X- ray binaries, it was not evident that many of the positrons could escape to lose energy and ultimately annihilate with electrons in the interstellar medium and thus lead to the emission of a narrow 511- keV line. For these models, our result implies that up to a few times 10(41) positrons escape per second from a typical hard LMXB. Positron production at this level from hard LMXBs in the Galactic bulge would reduce ( and possibly eliminate) the need for more exotic explanations, such as those involving dark matter. C1 [Weidenspointner, Georg; Skinner, Gerry; Jean, Pierre; Knoedlseder, Juergen; von Ballmoos, Peter; Bignami, Giovanni] UPS, CNRS, Ctr Etud Spatiale Rayonnements, Toulouse 4, France. [Weidenspointner, Georg; Diehl, Roland; Strong, Andrew W.] Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. [Weidenspointner, Georg] MPI Halbleiterlab, D-81739 Munich, Germany. [Skinner, Gerry] NASA, CRESST, Greenbelt, MD 20771 USA. [Skinner, Gerry] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Skinner, Gerry] Univ Maryland, Dept Astron, College Pk, MD 20742 USA. [Cordier, Bertrand; Schanne, Stephane] CEA Saclay, SAp, DAPNIA, DSM, F-91191 Gif Sur Yvette, France. [Winkler, Christoph] ESA, ESTEC, SCI SA, NL-2201 AZ Noordwijk, Netherlands. [Bignami, Giovanni] IUSS, I-27100 Pavia, Italy. RP Weidenspointner, G (reprint author), UPS, CNRS, Ctr Etud Spatiale Rayonnements, BP 44346, Toulouse 4, France. EM Georg.Weidenspointner@hll.mpg.de OI Bignami, Giovanni/0000-0001-9582-2450 NR 29 TC 121 Z9 121 U1 0 U2 4 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JAN 10 PY 2008 VL 451 IS 7175 BP 159 EP 162 DI 10.1038/nature06490 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 249GA UT WOS:000252214400035 PM 18185581 ER PT J AU Iyomoto, N Bandler, SR Brekosky, RP Brown, AD Chervenak, JA Finkbeiner, FM Kelley, RL Kilbourne, CA Porter, FS Sadleir, JE Smith, SJ Figueroa-Feliciano, E AF Iyomoto, N. Bandler, S. R. Brekosky, R. P. Brown, A. -D. Chervenak, J. A. Finkbeiner, F. M. Kelley, R. L. Kilbourne, C. A. Porter, F. S. Sadleir, J. E. Smith, S. J. Figueroa-Feliciano, E. TI Close-packed arrays of transition-edge x-ray microcalorimeters with high spectral resolution at 5.9 keV SO APPLIED PHYSICS LETTERS LA English DT Article AB We present measurements of high fill-factor arrays of superconducting transition-edge x-ray microcalorimeters designed to provide rapid thermalization of the x-ray energy. We designed an x-ray absorber that is cantilevered over the sensitive part of the thermometer itself, making contact only at normal-metal features. With absorbers made of electroplated gold, we have demonstrated an energy resolution between 2.4 and 3.1 eV at 5.9 keV on 13 separate pixels. We have determined the thermal and electrical parameters of the devices throughout the superconducting transition and, using these parameters, have modeled all aspects of the detector performance. (c) 2008 American Institute of Physics. C1 [Iyomoto, N.; Bandler, S. R.; Brekosky, R. P.; Brown, A. -D.; Chervenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Sadleir, J. E.; Smith, S. J.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Iyomoto, N.] Johns Hopkins Univ, Baltimore, MD 21218 USA. [Bandler, S. R.] Univ Maryland, College Pk, MD 20742 USA. [Brekosky, R. P.] Northrop Grumman Corp, Lanham, MD 20706 USA. [Finkbeiner, F. M.] RS Informat Syst Inc, Mclean, VA 22102 USA. [Figueroa-Feliciano, E.] MIT, Dept Phys, Cambridge, MA 02139 USA. RP Iyomoto, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM naoko.iyomoto@nasa.gov RI Brown, Ari/B-1693-2008; Bandler, Simon/A-6258-2010; Smith, Stephen/B-1256-2008; Porter, Frederick/D-3501-2012; Kelley, Richard/K-4474-2012 OI Bandler, Simon/0000-0002-5112-8106; Smith, Stephen/0000-0003-4096-4675; Porter, Frederick/0000-0002-6374-1119; NR 9 TC 31 Z9 31 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 7 PY 2008 VL 92 IS 1 AR 013508 DI 10.1063/1.2830665 PG 3 WC Physics, Applied SC Physics GA 250FA UT WOS:000252284200176 ER PT J AU Tinto, M Armstrong, JW Estabrook, FB AF Tinto, Massimo Armstrong, J. W. Estabrook, Frank B. TI Modulator noise suppression in the LISA time-delay interferometric combinations SO CLASSICAL AND QUANTUM GRAVITY LA English DT Article AB Laser Interferometer Space Antenna ( LISA) is a mission to detect and study low-frequency cosmic gravitational radiation through its influence on the phases of six modulated laser beams exchanged between three remote spacecraft. We previously showed how the measurements of some 18 time series of relative frequency or phase shifts could be combined ( 1) to cancel the phase noise of the lasers, ( 2) to cancel the Doppler fluctuations due to non-inertial motions of the six optical benches and ( 3) to remove the phase noise of the onboard reference oscillators required to track the photodetector fringes, all the while preserving signals from passing gravitational waves. Here we analyze the effect of the additional noise due to the optical modulators used for removing the phase fluctuations of the onboard reference oscillators. We use the recently measured noise spectrum of an individual modulator ( Klipstein et al 2006 Proc. 6th Int. LISA Symp. ( Greenbelt, MA) ( AIP Conf. Proc. vol 873) ed S M Merkowitz and J C Livas pp 19-23) to quantify the contribution of modulator noise to the first and second-generation time-delay interferometric ( TDI) combinations as a function of the modulation frequency. We show that modulator noise can be made smaller than the expected proof-mass acceleration and optical-path noises if the modulation frequencies are larger than approximate to 682 MHz in the case of the unequal-arm Michelson TDI combination X(1), approximate to 1.08 GHz for the Sagnac TDI combination alpha(1), and approximate to 706 MHz for the symmetrical Sagnac TDI combination zeta(1). These modulation frequencies are substantially smaller than previously estimated and may lead to less stringent requirements on the LISA's oscillator noise calibration subsystem. The measurements in Klipstein et al were performed in a laboratory experiment for a range of modulation frequencies, but we emphasize that, for the reference oscillator noise calibration algorithm to work, the modulation frequencies must be equal to the frequencies of the reference oscillators. C1 [Tinto, Massimo; Armstrong, J. W.; Estabrook, Frank B.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tinto, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 2 Z9 2 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0264-9381 J9 CLASSICAL QUANT GRAV JI Class. Quantum Gravity PD JAN 7 PY 2008 VL 25 IS 1 AR 015008 DI 10.1088/0264-9381/25/1/015008 PG 12 WC Astronomy & Astrophysics; Physics, Multidisciplinary; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 259HP UT WOS:000252930700009 ER PT J AU Kharuk, VI Ranson, KJ Dvinskaya, ML AF Kharuk, Viacheslav I. Ranson, K. Jon Dvinskaya, Maria L. TI Wildfires dynamic in the larch dominance zone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FIRE REGIMES; FOREST; LANDSCAPE; SIBERIA; USA AB A fire return intervals (FRI) for zone of larch dominance and "larch-mixed taiga'' ecotone was studied. Extreme fire events were connected with summer air temperature deviations. Average FRI determined from stem fire scar dating was 82 +/- 7 years for the zone of larch dominance, and 77 +/- 20 for the "larch-mixed taiga'' ecotone. For the zone of larch dominance FRI on north-east facing slopes was 86 +/- 11 years, for south-west facing slopes at 61 +/- 8 years, for flat terrain at 68 +/- 14 years, and for bogs 139 +/- 17 years. FRI decreased from 101 years in the 19th century to 65 years in the 20th century, for the zone of larch dominance, and from 97 years to 50 years for the "larch-mixed taiga'' ecotone. A climate and anthropogenic impact on this phenomenon was analyzed. The decrease of FRI may interfere with climate-driven migration of competitor species into zone of larch dominance, affecting biodiversity at high latitudes. C1 [Kharuk, Viacheslav I.; Dvinskaya, Maria L.] VN Sukachev Inst Forest, Krasnoyarsk 60036, Russia. [Ranson, K. Jon] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kharuk, VI (reprint author), VN Sukachev Inst Forest, Krasnoyarsk 60036, Russia. RI Ranson, Kenneth/G-2446-2012 OI Ranson, Kenneth/0000-0003-3806-7270 NR 17 TC 26 Z9 27 U1 0 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 5 PY 2008 VL 35 IS 1 AR L01402 DI 10.1029/2007GL032291 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 248UT UT WOS:000252183200002 ER PT J AU Freeborn, PH Wooster, MJ Hao, WM Ryan, CA Nordgren, BL Baker, SP Ichoku, C AF Freeborn, Patrick H. Wooster, Martin J. Hao, Wei Min Ryan, Cecily A. Nordgren, Bryce L. Baker, Stephen P. Ichoku, Charles TI Relationships between energy release, fuel mass loss, and trace gas and aerosol emissions during laboratory biomass fires SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIATIVE POWER OBSERVATIONS; COMBUSTION RATES; SOUTHERN AFRICA; FOREST FUELS; MODIS; DERIVATION; RETRIEVAL; TROPICS; TOTALS; CO2 AB Forty-four small-scale experimental fires were conducted in a combustion chamber to examine the relationship between biomass consumption, smoke production, convective energy release, and middle infrared (MIR) measurements of fire radiative energy (FRE). Fuel bed weights, trace gas and aerosol particle concentrations, stack flow rate and temperature, and concurrent thermal images were collected during laboratory-controlled burns of vegetative fuels. Using two different MIR thermal imaging systems, measurements of FRE taken at polar angles of. angle 48 degrees and angle 60 degrees were found not to be significantly different from each other (p < 0.05), but were significantly different from those obtained at. angle 76 degrees. A simple linear regression revealed that less than 12% of the variation in biomass consumption remained unexplained by the measured FRE regardless of MIR sensor characteristics, fuel type, or viewing angle. Measurements of FRE detected per unit of dry organic material consumed ranged from 1.29 to 4.18 MJ/ kg, corresponding to an average of 12 +/- 3% of the higher heating value of the biomass. Whole-fire emission factors agreed with previously reported values, and emission ratios relating total mass production to FRE were determined for CO2, CO, NO, NO2, and particulate matter less than 2.5 mu m in aerodynamic diameter. A heat balance performed on the system showed that the release of convective energy could be predicted from a measurement of FRE (r(2) >= 0.84), and together these two modes of heat transfer accounted for 61 +/- 13% of the total, potential heat of combustion available in the preburn solid fuel. C1 [Freeborn, Patrick H.; Wooster, Martin J.] Kings Coll London, Dept Geog, London WC2R 2LS, England. [Freeborn, Patrick H.; Hao, Wei Min; Ryan, Cecily A.; Nordgren, Bryce L.; Baker, Stephen P.] Rocky Mt Res Stn, Fire Sci Lab, Missoula, MT 59808 USA. [Ichoku, Charles] Univ Maryland, Earth Sci Syst Interdisciplinary Ctr, College Pk, MD 20742 USA. [Ichoku, Charles] NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD USA. RP Freeborn, PH (reprint author), Kings Coll London, Dept Geog, London WC2R 2LS, England. EM patrick.freeborn@kcl.ac.uk RI Ichoku, Charles/E-1857-2012 OI Ichoku, Charles/0000-0003-3244-4549 NR 48 TC 62 Z9 63 U1 3 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 5 PY 2008 VL 113 IS D1 AR D01301 DI 10.1029/2007JD008679 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 248UV UT WOS:000252183400001 ER PT J AU Huang, XC Habershon, S Bowman, JM AF Huang, Xinchuan Habershon, Scott Bowman, Joel M. TI Comparison of quantum, classical, and ring-polymer molecular dynamics infra-red spectra of Cl-(H2O) and H+(H2O)(2) SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PROTONATED WATER DIMER; GAS-PHASE; POTENTIAL-ENERGY; VIBRATIONS; MULTIMODE; H5O2+; ION; OH AB We present a comparison of the infra-red spectra of Cl-(H2O) and H+(H2O)(2) obtained with classical and ring-polymer molecular dynamics with previous quantum calculations. Full-dimensional ab initio-based potential and dipole-moment surfaces are used in these calculations. (C) 2007 Elsevier B.V. All rights reserved. C1 [Bowman, Joel M.] Emory Univ, Dept Chem, Atlanta, GA 30322 USA. [Bowman, Joel M.] Emory Univ, Cherry L Emerson Ctr Sci Computat, Atlanta, GA 30322 USA. [Huang, Xinchuan] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Habershon, Scott] Univ Oxford, Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. RP Bowman, JM (reprint author), Emory Univ, Dept Chem, Atlanta, GA 30322 USA. EM jmbowma@emory.edu RI HUANG, XINCHUAN/A-3266-2013; Habershon, Scott/O-6597-2014 OI Habershon, Scott/0000-0001-5932-6011 NR 18 TC 18 Z9 18 U1 3 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JAN 4 PY 2008 VL 450 IS 4-6 BP 253 EP 257 DI 10.1016/j.cplett.2007.11.048 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 255YH UT WOS:000252694000015 ER PT J AU Fletcher, LN Irwin, PGJ Orton, GS Teanby, NA Achterberg, RK Bjoraker, GL Read, PL Simon-Miller, AA Howett, C de Kok, R Bowles, N Calcutt, SB Hesman, B Flasar, FM AF Fletcher, L. N. Irwin, P. G. J. Orton, G. S. Teanby, N. A. Achterberg, R. K. Bjoraker, G. L. Read, P. L. Simon-Miller, A. A. Howett, C. de Kok, R. Bowles, N. Calcutt, S. B. Hesman, B. Flasar, F. M. TI Temperature and composition of Saturn's polar hot spots and hexagon SO SCIENCE LA English DT Article ID HUBBLE-SPACE-TELESCOPE; ATMOSPHERIC DYNAMICS; CLOUD STRUCTURE; CASSINI/CIRS; PHOSPHINE; IMAGES; SYSTEM; WAVE AB Saturn's poles exhibit an unexpected symmetry in hot, cyclonic polar vortices, despite huge seasonal differences in solar flux. The cores of both vortices are depleted in phosphine gas, probably resulting from subsidence of air into the troposphere. The warm cores are present throughout the upper troposphere and stratosphere at both poles. The thermal structure associated with the marked hexagonal polar jet at 77 degrees N has been observed for the first time. Both the warm cyclonic belt at 79 degrees N and the cold anticyclonic zone at 75 degrees N exhibit the hexagonal structure. C1 [Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A.; Read, P. L.; Howett, C.; de Kok, R.; Bowles, N.; Calcutt, S. B.] Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. [Orton, G. S.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Achterberg, R. K.; Bjoraker, G. L.; Simon-Miller, A. A.; Hesman, B.; Flasar, F. M.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fletcher, LN (reprint author), Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. EM fletcher@atm.ox.ac.uk RI Fletcher, Leigh/D-6093-2011; Flasar, F Michael/C-8509-2012; Bjoraker, Gordon/D-5032-2012; Simon, Amy/C-8020-2012; OI Fletcher, Leigh/0000-0001-5834-9588; Simon, Amy/0000-0003-4641-6186; Calcutt, Simon/0000-0002-0102-3170; Teanby, Nicholas/0000-0003-3108-5775; Irwin, Patrick/0000-0002-6772-384X NR 23 TC 53 Z9 53 U1 0 U2 5 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD JAN 4 PY 2008 VL 319 IS 5859 BP 79 EP 81 DI 10.1126/science.1149514 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 247MM UT WOS:000252084000034 PM 18174438 ER PT J AU Comiso, JC Parkinson, CL Gersten, R Stock, L AF Comiso, Josefino C. Parkinson, Claire L. Gersten, Robert Stock, Larry TI Accelerated decline in the Arctic Sea ice cover SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OSCILLATION; EXTENTS; TRENDS; OCEAN AB Satellite data reveal unusually low Arctic sea ice coverage during the summer of 2007, caused in part by anomalously high temperatures and southerly winds. The extent and area of the ice cover reached minima on 14 September 2007 at 4.1 x 10(6) km(2) and 3.6 x 10(6) km(2), respectively. These are 24% and 27% lower than the previous record lows, both reached on 21 September 2005, and 37% and 38% less than the climatological averages. Acceleration in the decline is evident as the extent and area trends of the entire ice cover (seasonal and perennial ice) have shifted from about -2.2 and -3.0% per decade in 1979 1996 to about -10.1 and -10.7% per decade in the last 10 years. The latter trends are now comparable to the high negative trends of -10.2 and -11.4% per decade for the perennial ice extent and area, 1979-2007. C1 [Comiso, Josefino C.; Parkinson, Claire L.; Gersten, Robert; Stock, Larry] NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Greenbelt, MD 20771 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Cryospher Sci Branch, Code 614 1, Greenbelt, MD 20771 USA. EM josefino.c.comiso@nasa.gov RI Parkinson, Claire/E-1747-2012 OI Parkinson, Claire/0000-0001-6730-4197 NR 19 TC 709 Z9 778 U1 34 U2 187 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 3 PY 2008 VL 35 IS 1 AR L01703 DI 10.1029/2007GL031972 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 248UR UT WOS:000252183000003 ER PT J AU Gonzalez, WD Echer, E de Gonzalez, ALC Tsurutani, BT AF Gonzalez, W. D. Echer, E. de Gonzalez, A. L. Clua Tsurutani, B. T. TI Reply to comment by Y. I. Yermolaev and M.Y. Yermolaev on "Interplanetary origin of intense geomagnetic storms (Dst < -100 nT) during solar cycle 23" SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material C1 [Gonzalez, W. D.; Echer, E.; de Gonzalez, A. L. Clua] Inst Nacl Pesquisas Espaciais, BR-12245970 Sao Jose Dos Campos, SP, Brazil. [Tsurutani, B. T.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gonzalez, WD (reprint author), Inst Nacl Pesquisas Espaciais, CP 515, BR-12245970 Sao Jose Dos Campos, SP, Brazil. EM gonzalez@dge.inpe.br; eecher@dge.inpe.br; alicia@dge.inpe.br; bruce.t.tsurutani@jpl.nasa.gov NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 3 PY 2008 VL 35 IS 1 AR L01102 DI 10.1029/2007GL031856 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 248UR UT WOS:000252183000002 ER PT B AU Leggett, S Freedman, R Geballe, T Golimowski, D Lodieu, N Marley, M Pinfield, D Saumon, D Stephens, D Warren, S AF Leggett, S. Freedman, R. Geballe, T. Golimowski, D. Lodieu, N. Marley, M. Pinfield, D. Saumon, D. Stephens, D. Warren, S. BE VanBelle, G TI Properties of the coolest dwarfs SO 14TH CAMBRIDGE WORKSHOP ON COOL STARS, STELLAR SYSTEMS, AND THE SUN SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 14th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun CY NOV 05-10, 2006 CL Pasadena, CA ID DEEP SKY SURVEY; T-DWARFS; BROWN DWARF; SPACE-TELESCOPE; SPECTRAL CLASSIFICATION; ULTRACOOL DWARFS; L/T TRANSITION; PHOTOMETRY; CLOUDS; SPECTROSCOPY AB Eleven years after the discovery of the first T dwarf, a population of ultracool L and T dwarfs has been identified that is large enough to show a range of atmospheric properties. Also, model atmospheres are sufficiently advanced to study these properties in detail. Since the last Cool Stars meeting, several observational developments have aided in these studies. We present recent mid-infrared photometry and spectroscopy from the Spitzer Space Telescope which confirms the prevalence of vertical mixing in the atmospheres of L and T dwarfs. Hence, the 700 K to 2200 K L and T dwarf photospheres require several parameters for successful modelling: effective temperature, gravity, metallicity, grain sedimentation efficiency and vertical mixing efficiency. We also describe initial results of a search for ultracool dwarfs in the UKIRT Infrared Deep Sky Survey, and present the latest T dwarf found to date. We conclude with a discussion of the possible spectral indicators of Y dwarfs. C1 [Leggett, S.; Geballe, T.] Gemini N, 670 N Aohoku Pl, Hilo, HI 96720 USA. [Freedman, R.] NASA, Ames Res Ctr, SETI, Moffett Field, CA 94035 USA. [Golimowski, D.] Johns Hopkins Univ, Phys & Astr, Baltimore, MD 21218 USA. [Lodieu, N.] Inst Astrofis Canarias, E-38205 San Cristobal la Laguna, Spain. [Marley, M.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Pinfield, D.] Univ Hertfordshire, Inst Sci & Technol, Hatfield AL10 9AB, Herts, England. [Saumon, D.] Los Alamos Natl Lab, Los Alamos, NM 87545 USA. [Stephens, D.] Brigham Young Univ, Dept Phys & Astron, Provo, UT 84602 USA. [Warren, S.] Imperial Coll, Astrophys, Blackett Lab, London SW7 2AZ, England. RP Leggett, S (reprint author), Gemini N, 670 N Aohoku Pl, Hilo, HI 96720 USA. RI Marley, Mark/I-4704-2013 FU Gemini Observatory [GS-2006B-Q-36]; National Science Foundation (United States); PPARC (UK); National Research Council (Canada); CONICYT (Chile); Australian Research Council (Australia); CNPq (Brazil); CONICET (Argentina); NASA through JPL/Caltech; U.S. Department of Energy at Los Alamos National Laboratory [W-7405-ENG-36]; NASA Office of Space Sciences FX UKIDSS is made possible by the UK Infrared Telescope (UKIRT), the University of Cambridge Astronomical Survey Unit and the WFCAM Science Archive at the Royal Observatory Edinburgh. UKIRT is operated by the Joint Astronomy Centre for the UK Particle Physics and Astronomy Research Council (PPARC). Based on data obtained by program GS-2006B-Q-36 at Gemini Observatory, operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), PPARC (UK), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil) and CONICET (Argentina). SL and TG are supported by Gemini Observatory. This work also uses observations made with the Spitzer Space Telescope, operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support was provided by NASA through an award issued by JPL/Caltech. Support also provided under the auspices of the U.S. Department of Energy at Los Alamos National Laboratory by Contract W-7405-ENG-36. MS and DS acknowledge the support of the NASA Office of Space Sciences. NR 28 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 978-1-58381-331-7 J9 ASTR SOC P PY 2008 VL 384 BP 98 EP + PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BHQ83 UT WOS:000255549400011 ER PT B AU Fortney, JJ AF Fortney, Jonathan J. BE VanBelle, G TI Hot Jupiter model atmospheres in the Spitzer Era SO 14TH CAMBRIDGE WORKSHOP ON COOL STARS, STELLAR SYSTEMS, AND THE SUN SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 14th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun CY NOV 05-10, 2006 CL Pasadena, CA ID EXTRASOLAR PLANET; THERMAL STRUCTURE; DWARF; EMISSION; SPECTRA; ALBEDO AB The Spitzer Space Telescope has allowed observers to detect thermal flux from the atmospheres of hot Jupiters. We present model atmospheres of several of these planets and compare our computed infrared spectra to recent space-based and ground-based infrared observations. We also explore spectra as a function of orbital phase for a three-dimensional dynamical atmosphere model of planet HD 209458 b. The temperature structure and blackbody-like day-side spectra of the dynamical model is quite different than other models. We also discuss why hot Jupiters are predicted to be dark at visible wavelengths. C1 NASA, Ames Res Ctr, Washington, DC USA. RP Fortney, JJ (reprint author), NASA, Ames Res Ctr, Washington, DC USA. NR 20 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 978-1-58381-331-7 J9 ASTR SOC P PY 2008 VL 384 BP 264 EP 268 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BHQ83 UT WOS:000255549400029 ER PT B AU Basri, G Ramos-Stierle, F Soto, K Lewis, T Reiners, A Borucki, W Koch, D AF Basri, Gibor Ramos-Stierle, Francisco Soto, Kurt Lewis, Tristan Reiners, Ansgar Borucki, William Koch, David BE VanBelle, G TI The Kepler mission: Terrestrial extrasolar planets and stellar activity SO 14TH CAMBRIDGE WORKSHOP ON COOL STARS, STELLAR SYSTEMS, AND THE SUN SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 14th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun CY NOV 05-10, 2006 CL Pasadena, CA AB Kepler is a, NASA mission designed to determine the frequency and distribution of Earth-sized planets within 1 AU of F-M main sequence stars. This is done by searching for planetary transits. The mission will return up to 150,000 broad-band light curves with unprecedented precision (20 micromag) and 30 minute resolution continuously for several years. Along with a program to determine precise stellar parameters, the size and orbital distance of the planets can be estimated, as well as the relations between planets and the stars they orbit. Hundreds of terrestrial planets should be discovered if they are common. A null result would strongly imply that terrestrial planets are rare. The Kepler dataset is also a treasure-trove of information on stellar activity and rotation. We have begun a research program to understand and simulate stellar microvariability. We first study the Sun as a microvariable star (cf. Soto et al., this conference). Having derived laws which connect continuum variability with magnetic configurations, we explore photometry of simulated stars. This will lead to improved methods of finding rotation periods, understanding the change due to inclination (can we actually derive inclination?), mapping of magnetic distributions, and sizes and time-scales for active regions and starspots. Guest lnvestigators can propose targets that are not part of the exoplanet search during the mission. Kepler can greatly aid our understanding of the behavior of stellar activity as a function of stellar mass and age. C1 [Basri, Gibor; Ramos-Stierle, Francisco; Soto, Kurt; Lewis, Tristan; Reiners, Ansgar] Univ Calif Berkeley, Dept Astron, MC3411, Berkeley, CA 94720 USA. [Reiners, Ansgar] Univ Gottingen, Inst Astrophys, Busgenweg 2, D-37077 Gottingen, Germany. [Soto, Kurt] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. [Borucki, William; Koch, David] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Basri, G (reprint author), Univ Calif Berkeley, Dept Astron, MC3411, Berkeley, CA 94720 USA. FU Kepler Mission; NASA FX We would like to acknowledge support from the Kepler Mission,and from NASA through the "Living with a Star" program.We also had a number of helpful discussions with Sami Solanki, and the Stanford MDI data center. NR 10 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 978-1-58381-331-7 J9 ASTR SOC P PY 2008 VL 384 BP 281 EP + PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BHQ83 UT WOS:000255549400031 ER PT B AU Rebull, LM Stauffer, JR Wolff, SC Strom, SE AF Rebull, L. M. Stauffer, J. R. Wolff, S. C. Strom, S. E. BE VanBelle, G TI Rotation in young stars SO 14TH CAMBRIDGE WORKSHOP ON COOL STARS, STELLAR SYSTEMS, AND THE SUN SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 14th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun CY NOV 05-10, 2006 CL Pasadena, CA ID ORION NEBULA CLUSTER; PRE-MAIN-SEQUENCE; STELLAR ROTATION; ACCRETION DISKS; FLANKING FIELDS; TIME-SERIES; EVOLUTION; VARIABILITY; PERIODS AB The smallest molecular cores observed to date have at least similar to 6 orders of magnitude greater angular momentum per unit mass than the Sun, suggesting that they would greatly exceed the breakup velocity if no angular momentum was lost during the star formation process. Therefore, an angular momentum regulation mechanism must be at work in the pre-main-sequence phase, and disks are often invoked as the solution to the angular momentum problem. Thanks to large-format CCDs, more than 1000 periods for young stars are now known (with more being presented at this conference), and with the Spitzer Space Telescope, we have the ability to get reliable circumstellar disk indicators for many 1000s of stars at once. Now, for the first time, we may have enough stars to start to constrain the angular momentum loss mechanism in a meaningful fashion. In this contribution, we review the observations made to date of rotation in pre-main-sequence low-mass stars. C1 [Rebull, L. M.; Stauffer, J. R.] CALTECH, Spitzer Sci Ctr, Jet Propuls Lab, 1200 E Calif Blvd,MS 220-6, Pasadena, CA 91101 USA. [Wolff, S. C.; Strom, S. E.] Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Rebull, LM (reprint author), CALTECH, Spitzer Sci Ctr, Jet Propuls Lab, 1200 E Calif Blvd,MS 220-6, Pasadena, CA 91101 USA. NR 27 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 978-1-58381-331-7 J9 ASTR SOC P PY 2008 VL 384 BP 327 EP + PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BHQ83 UT WOS:000255549400035 ER PT S AU Zhang, H Mudawar, I Hasan, MM AF Zhang, Hui Mudawar, Issam Hasan, Mohammad M. GP IEEE TI Application of flow boiling for thermal management of electronics in microgravity and reduced gravity space systems SO 2008 11TH IEEE INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS, VOLS 1-3 SE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems LA English DT Proceedings Paper CT 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems CY MAY 28-31, 2008 CL Orlando, FL SP IEEE DE microgravity; reduced gravity; boiling; critical heat flux ID CRITICAL HEAT-FLUX; TRIGGER MECHANISM; CHF MECHANISM; ORIENTATION; WALL; LENGTH; MODEL; LONG AB Large density differences between liquid and vapor create buoyancy effects in the presence of a gravitational field. Such effects can play an important role in two-phase fluid flow and heat transfer, especially critical heat flux (CHF). CHF poses significant risk to electronic devices, and the ability to predict its magnitude is crucial to both the safety and reliability of these devices. Variations in the gravitational field perpendicular to a flow boiling surface can take several forms, from flows at different orientations at 1 g(e) to the microgravity environment of planetary orbit, to the reduced gravity on the Moon and Mars, and the high g's encountered in fighter aircraft during fast aerial maneuvers. While high coolant velocities can combat the detrimental effects of reduced gravity, limited power budget in space systems imposes stringent constraints on coolant flow rate. Thus, the task of dissipating the heat must be accomplished with the lowest possible flow velocity while safely avoiding CHF. In this study, flow-boiling CHF is investigated on Earth as well as in reduced gravity parabolic flight experiments using FC-72 as working fluid. CHF showed sensitivity to gravity at low velocities, with microgravity yielding significantly lower CHF values compared to those at 1 g(e). Differences in CHF value decreased with increasing flow velocity until a velocity limit was reached above which the effects of gravity became inconsequential. This proves existing data, correlations, and models developed from 1 g(e) studies can be employed with confidence to design reduced gravity thermal management systems, provided the flow velocity is maintained above this limit. This study discusses two powerful predictive tools. The first, which consist of three dimensionless criteria, centers on determination of the velocity limit. The second is a theoretically based model for flow boiling CHF in reduced gravity below this velocity limit. C1 [Zhang, Hui] BTPFL, Mech Engn Bldg,585 Purdue Mall, W Lafayette, IN 47907 USA. [Zhang, Hui; Mudawar, Issam] Purdue Univ Int Elect Cooling Alliance, W Lafayette, IN 47907 USA. [Hasan, Mohammad M.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhang, H (reprint author), BTPFL, Mech Engn Bldg,585 Purdue Mall, W Lafayette, IN 47907 USA. EM mudawar@ecn.purdue.edu FU National Aeronautics and Space Administration [NNC04GA54G] FX Manuscript received April 03, 2008; revised July 11, 2008. First published January 09, 2009; current version published July 22, 2009. This work was supported by the National Aeronautics and Space Administration under Grant NNC04GA54G. This work was recommended for publication by Associate Editor T. Lee upon evaluation of the reviewers comments. NR 20 TC 2 Z9 2 U1 0 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1087-9870 BN 978-1-4244-1700-1 J9 INTERSOC C THERMAL T PY 2008 BP 949 EP + DI 10.1109/ITHERM.2008.4544370 PG 3 WC Thermodynamics; Engineering, Electrical & Electronic; Engineering, Mechanical SC Thermodynamics; Engineering GA BID58 UT WOS:000258726500126 ER PT S AU Sehirlioglu, A Sayir, A AF Sehirlioglu, A. Sayir, A. GP IEEE TI Effects of Excess Lead-Oxide and Bismuth-Oxide Content on the Electrical Properties of High-Temperature Bismuth Scandium Lead Titanate Ceramics SO 2008 17TH IEEE INTERNATIONAL SYMPOSIUM ON THE APPLICATIONS OF FERROELECTRICS SE IEEE International Symposium on Applications of Ferroelectrics LA English DT Proceedings Paper CT 17th IEEE International Symposium on Applications of Ferroelectrics CY FEB 23-28, 2008 CL Santa Fe, NM SP IEEE AB Aeronautic and aerospace applications require piezoelectric materials that can operate at high temperatures. The air-breathing aeronautic engines can use piezoelectric actuators for active combustion control for fuel modulation to mitigate thermo-acoustic instabilities and/or for gas flow control to improve efficiency. The principal challenge for the insertion of piezoelectric materials is their limitation for upper use temperature and this limitation is due to low Curie temperature and increasing conductivity. We investigated processing, microstructure and property relationship of (1-x)BiScO3-(x)PbTiO3 (BS-PT) composition as a promising high temperature piezoelectric. The effect of excess Pb and Bi and their partitioning in grain boundaries were studied using impedance spectroscopy, ferroelectric, and piezoelectric measurement techniques. Excess Pb addition increased the grain boundary conduction and the grain boundary area (average grain size was 24.8 mu m, and 1.3 mu m for compositions with 0at.% and 5at.% excess Pb, respectively) resulting in ceramics with higher losses (tan delta= 0.9 and 1.7 for 0at.% and 5at.% excess Pb at 350 degrees C and at 10kHz) that were not resistive enough to pole. Excess Bi addition increased the resistivity (rho(grain) = 4.1x10(10) Omega.cm and 19.6x10(10) Omega.cm for compositions with 0at.% and 5at.% excess Bi, respectively), improved poling, and increased the piezoelectric coefficient from 137 to 197 pC/N for 5at.% excess Bi addition. In addition, loss tangent decreased more than one order of magnitude at elevated temperatures (>300 degrees C). For all compositions the activation energy of the conducting species was similar (approximate to 0.35-0.40 eV). C1 [Sehirlioglu, A.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. [Sayir, A.] Case Western Reserve Univ, Cleveland, OH 44106 USA. RP Sehirlioglu, A (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1099-4734 BN 978-1-4244-2744-4 J9 IEEE INT FERRO PY 2008 BP 426 EP + PG 2 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA BLN41 UT WOS:000270584000155 ER PT B AU Fang, WC Kedar, S AF Fang, Wai-Chi Kedar, Sharon GP IEEE TI System architecting and system-on-chip design of intelligent sensor networks for active volcanoes SO 2008 2ND ANNUAL IEEE SYSTEMS CONFERENCE LA English DT Proceedings Paper CT 2nd Annual IEEE Systems Conference CY APR 07-10, 2008 CL Montreal, CANADA SP IEEE DE volcano monitoring system; sensor networks; system-on-chip; wireless communication; intelligent surveillance system AB In this paper, an intelligent surveillance system using sensor networks for monitoring active volcanoes has been presented. While wireless sensor networks can generically be used for a wide variety of applications, breakthrough innovations are most often achieved when driven by a genuine need or application, with its specific system-level and science-related requirements and objectives. Hence, our work focuses on the development of a specific surveillance system for active volcanoes. We combine sensor network system engineering with systems-on-chip implementation to develop an integrated surveillance system called Sensor Networks for Active Volcanoes (SNAV). We report SNAV specific science-related requirements and system-level operations for this surveillance system. Development of the SNAV node system-on-chip (SoC) is then presented. A rapid SoC prototyping of the control and computing subsystem was implemented as an exploratory device based on reconfigurable SoC platform architecture A low-power radio was developed as an embedded wireless communication core for SNAV system-on-chip designs. The success of this work enables low-power low-cost sensor networks for intelligent surveillance system applications. C1 [Fang, Wai-Chi] Natl Chiao Tung Univ, TSMC, Hsinchu 300, Taiwan. [Fang, Wai-Chi; Kedar, Sharon] CALTECH, NASA Jet Prop Lab, Pasadena, CA 91109 USA. RP Fang, WC (reprint author), Natl Chiao Tung Univ, TSMC, Hsinchu 300, Taiwan. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2149-7 PY 2008 BP 30 EP + PG 3 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BHW80 UT WOS:000257097600006 ER PT B AU Thomas, B Maestrini, A Matheson, D Mehdi, L de Maagt, P AF Thomas, B. Maestrini, A. Matheson, D. Mehdi, L. de Maagt, P. GP IEEE TI Design of an 874 GHz Biasable Sub-Harmonic Mixer Based on MMIC Membrane Planar Schottky Diodes SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB We report upon the development of a 874 GHz bias-able sub-harmonic mixer using planar Schottky diodes. The MMIC integrates two planar Schottky diodes in a balanced configuration, stripline filtering elements, and on-chip capacitor on a 5 microns thick GaAs membrane. Predicted performance gives optimal conversion losses of 10 dB and a 3 dB bandwidth from 820 to 920 GHz This work represents the highest frequency Schottky based MMIC sub-harmonic mixer development to-date. C1 [Thomas, B.; Matheson, D.] SSTD, Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. [Maestrini, A.] LERMA, Observ Paris, F-75014 Paris, France. [Thomas, B.; Mehdi, L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [de Maagt, P.] ESTEC, ESA, NL-2200 AG Noordwijk, Netherlands. RP Thomas, B (reprint author), SSTD, Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. FU ESA/ESTEC [16142/02/NL/EC] FX The authors wish to thank Mr. Gill and Mr. Lin at JPL for the circuit fabrication and mounting, Mr. Beardsley and Mr. Hiscock at RAL for the block manufacturing. This work has been partly supported by ESA/ESTEC under contract number 16142/02/NL/EC, and carried out at the California Institute of Technology, Jet Propulsion Laboratory under contract from National Aeronautics and Space Administration. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 27 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700014 ER PT B AU Bruneau, PJ Janzen, HD Ward, JS AF Bruneau, Peter J. Janzen, Hal D. Ward, John S. GP IEEE TI Machining of Terahertz Split-Block Waveguides with Micrometer Precision SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID CHAIN AB Evolutionary improvements in tooling and techniques are allowing increasingly complicated waveguide circuits to be fabricated with conventional end-mill machining at frequencies ranging from millimeter-wavelengths up to several terahertz. Machining precision is now approaching the limits of what can be measured with an optical microscope, with the measured dimensions of the highest-precision components typically within 2 mu m of the nominal design values. We summarize the capabilities of the Space Instruments Shop at JPL and show examples of recently machined components. C1 [Bruneau, Peter J.; Janzen, Hal D.; Ward, John S.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bruneau, PJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 48 EP 49 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700025 ER PT B AU Ward, JS Lee, KA Kawamura, J Chattopadhyay, G Stek, P AF Ward, John S. Lee, Karen A. Kawamura, Jonathan Chattopadhyay, Goutam Stek, Paul GP IEEE TI Sensitive Broadband SIS Receivers for Microwave Limb Sounding SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID SATELLITE AB We present the measured performance of a sensitive new broadband waveguide sideband-separating superconductor-insulator-superconductor (SIS) heterodyne receiver with very wide IF bandwidth that is being developed for a future space-borne microwave limb sounder to study the earth's atmosphere. The prototype receiver has measured noise temperature below 100 K from 190 to 300 GHz, and features 24 GHz of sideband-separated output. Measured sideband image rejection is typically 13 dB. The receiver features a three-section suspended stripline 6-18 GHz quadrature hybrid coupler integrated into the mixer waveguide block to minimize phase errors and standing waves to provide maximum bandwidth and image rejection. The high spectral resolution achieved with heterodyne detection will enable precision measurement of the profiles of pressure-broadened thermal emission spectral lines. Broad instantaneous bandwidth will enable multiple chemical species in the atmosphere to be measured simultaneously without retuning the receiver. C1 [Ward, John S.; Lee, Karen A.; Kawamura, Jonathan; Chattopadhyay, Goutam; Stek, Paul] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ward, JS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 50 EP 51 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700026 ER PT B AU Ward, JS Chattopadhyay, G Gill, J Javadi, H Lee, C Lin, R Maestrinia, A Maiwald, F Mehdi, I Schlecht, E Siegel, P AF Ward, John S. Chattopadhyay, Goutam Gill, John Javadi, Hamid Lee, Choonsup Lin, Robert Maestrinia, Alain Maiwald, Frank Mehdi, Imran Schlecht, Erich Siegel, Peter GP IEEE TI Tunable Broadband Frequency-Multiplied Terahertz Sources SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID GHZ AB Continued advances in Schottky diode frequency multiplier technology enable solid-state submillimeter-wave and terahertz sources with higher output power tunable over broader bandwidths than have been previously demonstrated. For example, 630 mu W of continuous-wave power were measured at 900 GHz at room temperature and 1.4 mW at 920 GHz from the same frequency multiplier chain when cooled to 77 K. The 3 dB bandwidth of this chain is about 100 GHz. Simulations predict that an additional tripler driven by this new 900 GHz tripler chip could produce 1 to 2 mu W at 2.7 THz when operated at 77 K, which is sufficient to pump a superconducting heterodyne mixer. We present these recent results as well as summarize the current state-of-the-art of JPL frequency multiplied sources. Finally, we review the limitations of our current generation of frequency multipliers to predict that future advances in amplifier and diode technology should enable at least a ten-fold increase in available tunable output power from solid state frequency-multiplied sources. C1 [Ward, John S.; Chattopadhyay, Goutam; Gill, John; Javadi, Hamid; Lee, Choonsup; Lin, Robert; Maiwald, Frank; Mehdi, Imran; Schlecht, Erich; Siegel, Peter] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Maestrinia, Alain] Univ Paris 06, Observ Paris, Paris, France. RP Ward, JS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 52 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700027 ER PT B AU Cooper, KB Dengler, RJ Llombart, N Bryllert, T Chattopadhyay, G Schlecht, E Gill, J Lee, C Skalare, A Mehdi, I Siegel, PH AF Cooper, Ken B. Dengler, Robert J. Llombart, Nuria Bryllert, Tomas Chattopadhyay, Goutarn Schlecht, Erich Gill, John Lee, Choonsup Skalare, Anders Mehdi, Imran Siegel, Peter H. GP IEEE TI Concealed Object Contrast Enhancement Using Radar Methods in a Submillimeter-Wave Active Imager SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID GHZ AB A single-pixel, active, heterodyne submillimeter-wave imager has been developed to detect concealed weapons on persons at standoff ranges of many meters. A major imaging challenge is that a target's reflected power often yields poor contrast of concealed objects because of specular scattering. To address this problem we have adapted high-resolution radar techniques to a 600 GHz active imager and generated three-dimensional through-clothes images of concealed objects with cm-scale resolution. C1 [Cooper, Ken B.; Dengler, Robert J.; Chattopadhyay, Goutarn; Schlecht, Erich; Gill, John; Lee, Choonsup; Skalare, Anders; Mehdi, Imran] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Llombart, Nuria; Bryllert, Tomas; Siegel, Peter H.] CALTECH, Pasadena, CA 91125 USA. RP Cooper, KB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 135 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700073 ER PT B AU Elachi, C AF Elachi, Charles GP IEEE TI Robotic Space and Earth Science 2020 SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Elachi, C (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 157 EP 157 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700085 ER PT B AU Chattopadhyay, G Ward, JS Manohara, H Toda, R AF Chattopadhyay, Goutam Ward, John S. Manohara, Harish Toda, Risaku GP IEEE TI Deep Reactive Ion Etching Based Silicon Micromachined Components at Terahertz Frequencies for Space Applications SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID WAVE-GUIDE; W-BAND AB Jet Propulsion Laboratory (JPL) is using Deep Reactive Ion Etching (DRIE) based silicon micromachining capabilities to develop the critical waveguide components at submillimeter wavelengths that will lead to highly integrated multi-pixel spectrometers, imagers, and radars. In this paper we describe the design and fabrication of silicon micromachined critical waveguide components operating in the 325-500 GHz frequency band for space applications. We also address the challenges of testing these devices when interfaced with metal waveguide test fixtures. C1 [Chattopadhyay, Goutam; Ward, John S.; Manohara, Harish; Toda, Risaku] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chattopadhyay, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 192 EP 193 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700105 ER PT B AU Griffin, M AF Griffin, Michael GP IEEE TI The Magic of Science SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE C1 NASA, Washington, DC 20546 USA. RP Griffin, M (reprint author), NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 196 EP 196 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700107 ER PT B AU Maestrini, A Ward, J Chattopadhyay, G Schlecht, E Gill, J Lee, C Javadi, H Mehdi, I AF Maestrini, Alain Ward, John Chattopadhyay, Goutam Schlecht, Erich Gill, John Lee, Choonsup Javadi, Hamid Mehdi, Imran GP IEEE TI In-Phase Power Combining of Submillimeter-Wave Multipliers SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB Submillimeter-wave multiplier circuits can either be optimized for maximum efficiency or maximum output power depending on the application. However, it is always desirable to have maximum output power without sacrificing efficiency. To accomplish this goal we have proposed and demonstrated in;. phase power combining of submillimeter-wave multiplier chips. We report on the design, fabrication and characterization of a 260-340 GHz tripler that utilizes two mirror-image chips and produces a peak of 22 mW with 11% efficiency. This source is then used to drive a two-chip 790-950 GHz tripler. Preliminary results obtained from this LO chain are 0.7 mW at 890 GHz at room temperature. This technology advancement now makes it possible to extend the frequency coverage of multiplier based sources well into the THz; range. C1 [Maestrini, Alain] Univ Paris 06, LERMA, Observ Paris, F-75252 Paris 05, France. [Ward, John; Chattopadhyay, Goutam; Schlecht, Erich; Gill, John; Lee, Choonsup; Javadi, Hamid; Mehdi, Imran] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Maestrini, A (reprint author), Univ Paris 06, LERMA, Observ Paris, F-75252 Paris 05, France. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 232 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700125 ER PT B AU Samoska, L Pukala, D Soria, M Sadowy, G AF Samoska, Lorene Pukala, David Soria, Mary Sadowy, Gregory GP IEEE TI A G-Band Multi-Chip MMIC T/R Module for Radar Applications SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB In this paper, we describe the design and measurements of a MMIC amplifier-based multi-chip Transmit/Receive (T/R) Module for radar applications in G-Band (140-220 GHz). The module is design with InP HEMT MMIC power amplifiers for the transmit channel and InP MMIC low noise amplifiers for the receive channel. Arrays of these 150 GHz T/R modules could be used for applications such as automotive radar and landing radar. C1 [Samoska, Lorene; Pukala, David; Soria, Mary; Sadowy, Gregory] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Samoska, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 374 EP 375 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700198 ER PT B AU Drouin, BJ Cooper, K Stachnik, RA Pearson, JC AF Drouin, Brian J. Cooper, Ken Stachnik, Robert A. Pearson, John C. GP IEEE TI Submillimeter Wave Spectroscopy and the Search for Life on Planets SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB Absorption and emission of gases in the submillimeter wavelengths is currently exploited for laboratory spectroscopy as well as remote astronomy and limb sounding. We are developing a field-ready submillimeter spectrometer that will enable in-situ sensing with a goal for characterization of biogenic gases and life tracers. C1 [Drouin, Brian J.; Cooper, Ken; Stachnik, Robert A.; Pearson, John C.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Drouin, BJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 393 EP 395 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700205 ER PT B AU Trischman, JA Bennett, JR Melendez, KA Summers, BF Sorensen, J Cooper, KB Siegel, PH AF Trischman, J. A. Bennett, J. R. Melendez, K. A. Summers, B. F. Sorensen, J. Cooper, K. B. Siegel, P. H. GP IEEE TI Inverse Synthetic Aperture Radar Imaging at 580 GHz SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB We have demonstrated sub-centimeter resolution Inverse Synthetic Aperture Radar (ISAR) imaging using a 580 GHz, frequency modulated continuous wave (FMCW) radar. This ISAR technique uses pulse compression possible with the FMCW waveform to achieve resolution in range, and exploits rotation of the target to achieve resolution in cross-range. The technique relies on the illumination of the entire target rather than scanning with a narrow beam, which permits larger ranges or smaller apertures than real-aperture approaches. The data collection time required for an ISAR image is less than the collection time with a mechanically scanned beam, which is an advantage in highly dynamic scenarios. The ISAR algorithms presented here accommodate radial motion of the target and non-uniform rotation rates. Thus, the algorithms are suitable for applications where the target motion is not under the control of the observer. These algorithms enhance submillimeter-wave radar technology for surveillance and concealed-object detection. C1 [Trischman, J. A.; Bennett, J. R.; Melendez, K. A.; Summers, B. F.; Sorensen, J.] Sci Applicat Int Corp, San Diego, CA 92121 USA. [Cooper, K. B.; Siegel, P. H.] Jet Propuls Lab, Pasadena, CA 91109 USA. RP Trischman, JA (reprint author), Sci Applicat Int Corp, San Diego, CA 92121 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 396 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700206 ER PT B AU Karasik, BS Pereverzev, SV Wei, J Olaya, D Gershenson, ME Sergeev, AV Cantor, R AF Karasik, Boris. S. Pereverzev, Sergey V. Wei, Jian Olaya, David Gershenson, Michael E. Sergeev, Andrei V. Cantor, Robin GP IEEE TI Ultra-Sensitive Hot-Electron Nanobolometers for THz Astrophysics SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB The background-limited spectral imaging of the early Universe requires terahertz (THz) detectors with the sensitivity 2-3 orders of magnitude better than that of the state-of-the-art bolometers. To realize this sensitivity without sacrificing the operating speed, the sensing element of a bolometric detector should have an exceptionally high thermal isolation from the environment combined with an ultrasmall heat capacity. We have demonstrated that this goal can be achieved by realizing a superconducting hot-electron nanobolometer whose design blocks photon and phonon energy exchange through its contact leads. The remaining coupling due to electron-phonon interaction provides thermal control at a level of one thousandth of the quantum of thermal conductance G(Q) approximate to 1 [pW/K] x T. These hot-electron nanobolometers with a beat capacity of similar to 0.1 aJ/K will be sufficiently sensitive for registration of single THz photons. These devices are very promising for submillimeter astronomy and other applications based on quantum calorimetry and photon counting. C1 [Karasik, Boris. S.; Pereverzev, Sergey V.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Wei, Jian; Olaya, David; Gershenson, Michael E.] Rutgers State Univ, Piscataway, NJ 08854 USA. [Sergeev, Andrei V.] SUNY Buffalo, Buffalo, NY 14260 USA. [Cantor, Robin] Star Cryolectron, Santa Fe, NM 87508 USA. RP Karasik, BS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Wei, Jian/B-2137-2014 OI Wei, Jian/0000-0002-8831-6418 NR 1 TC 0 Z9 0 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 403 EP 403 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700210 ER PT B AU Manohara, HM Toda, R Lin, RH Liao, A Kowalczyk, R Kaul, AB Mojarradi, MM AF Manohara, H. M. Toda, R. Lin, R. H. Liao, A. Kowalczyk, R. Kaul, A. B. Mojarradi, M. M. GP IEEE TI Vacuum Microelectronics Applications Using Carbon Nanotube Cathodes SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID FIELD-EMISSION CATHODES AB We will present the recent advances in carbon nanotube bundle array based field emission electron source development. These cathodes are being applied for developing new vacuum microelectronic devices. Some application issues, cathode life time, current density influencing factors, and a novel electrode integration technique will be described. C1 [Manohara, H. M.; Toda, R.; Lin, R. H.; Liao, A.; Kowalczyk, R.; Kaul, A. B.; Mojarradi, M. M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Manohara, HM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 426 EP 427 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700224 ER PT B AU Lambert, JL Bender, M Englich, FV Fisher, A Quinn, R Onstott, TC Zent, AP AF Lambert, James L. Bender, Michael Englich, Forian V. Fisher, Anita Quinn, Richard Onstott, Tullis C. Zent, Aaron P. GP IEEE TI In Situ Gas Sensing Instrument for Planetary Science SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE C1 [Lambert, James L.; Englich, Forian V.; Fisher, Anita] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. [Bender, Michael; Onstott, Tullis C.] Princeton Univ, Princeton, NJ 08544 USA. [Quinn, Richard; Zent, Aaron P.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lambert, JL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 440 EP 440 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700230 ER PT B AU Llombart, N Skalare, A Gill, JJ Siegel, PH AF Llombart, Nuria Skalare, Anders Gill, John J. Siegel, Peter H. GP IEEE TI High Efficiency Submillimeter-wave Imaging Array SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB The period of a focal array is limited by the angular sampling and the f number of the system. This fact will limit the efficiency of imaging array systems to around 50%. Recently it been demonstrated that the use of a dielectric layer on top of an array of apertures can improve this efficiency limit. In this paper, we describe a similar structure that improves the efficiency in imaging applications and that it is easy to manufacture due to its compatibility with planar lithographic techniques. C1 [Llombart, Nuria; Skalare, Anders; Gill, John J.; Siegel, Peter H.] CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RP Llombart, N (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 476 EP 478 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700250 ER PT B AU Goldsmith, PF AF Goldsmith, Paul F. GP IEEE TI Submillimeter Spectroscopy - Water and Oxygen: Where are These Key Species in the Interstellar Medium? SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE ID ASTRONOMY-SATELLITE OBSERVATIONS; RHO-OPHIUCHI CLOUD; MOLECULAR CLOUDS; SAGITTARIUS-B2; ABSORPTION; ABUNDANCE; CHEMISTRY; LINES; O-2 AB Water and oxygen are two of the key species necessary for life. Water vapor and molecular oxygen are predicted to be abundant gas phase species in dense regions of the interstellar medium where formation of new stars and planetary systems is taking place. But observations to date have revealed that the abundances of H(2)O and O(2) are much lower than expected, and suggest that a surprisingly large amount of atomic oxygen (OI) is present in molecular clouds. Resolving the disagreement between theory and observations will require better spectroscopic observations from new satellite and airborne facilities which fortunately will become available in the next few years. In this talk I briefly review the observations to date, the issues for theoretical models, and suggest what future observations will help resolve this "oxygen problem". C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Goldsmith, PF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 500 EP 502 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700262 ER PT B AU Kim, SW Zimmerman, JD Focardi, P Wu, DH Gossard, AC Sherwin, MS AF Kim, Sangwoo Zimmerman, Jeramy D. Focardi, Paolo Wu, Dong Ho Gossard, Arthur C. Sherwin, Mark S. GP IEEE TI Room Temperature Terahertz Detection based on Plasma Resonance of Electrons in an Antenna-Coupled GaAs MESFET SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB Plasma resonance of electrons is observed in an Antenna-Coupled Metal-Semiconductor-Field-Effect-Transistor (MESFET) by sweeping bins voltages. This resonant absorption is exploited to realize a room temperature terahertz; detector with a measured Noise Equivalent Power (NEP) similar to 5x10(-8) W/Hz(1/2). C1 [Kim, Sangwoo; Sherwin, Mark S.] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. [Zimmerman, Jeramy D.; Gossard, Arthur C.] Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. [Focardi, Paolo] Jet Prop Lab, Pasadena, CA 91109 USA. [Wu, Dong Ho] Naval Res Lab, Washington, DC 20375 USA. RP Kim, SW (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RI Zimmerman, Jeramy/C-2273-2009 OI Zimmerman, Jeramy/0000-0001-8936-5345 FU NSF-DMR [0703925] FX Work supported by NSF-DMR 0703925 and Naval Research. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 568 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700303 ER PT B AU Kangaslahti, P Tanner, A Gaier, T Lambrigtsen, B O'Dwyer, I Pukala, D AF Kangaslahti, Pekka Tanner, Alan Gaier, Todd Lambrigtsen, Bjorn O'Dwyer, Ian Pukala, David GP IEEE TI Millimeter Wave Synthetic Thinned Aperture Radiometer SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB Imaging of temperature and humidity profiles of the atmosphere on a global scale with high temporal and spatial resolution requires a large aperture millimeter wave radiometer on geostationary orbit We developed a prototype 50 GHz millimeter wave synthetic aperture radiometer and Low Noise Amplifier (LNA) MMICs and receiver technology for a 180 GHZ synthetic aperture system. The 50 GHz system was tested in laboratory and in field with a 4-meter target disk by refocusing the array to near-field by digital phase corrections. The 180 GHZ system development included novel 180 GHz MMIC LNAs that provide more than 100 GHz of bandwidth with more than 15 dB of gain and a noise figure of 3.7 dB. C1 [Kangaslahti, Pekka; Tanner, Alan; Gaier, Todd; Lambrigtsen, Bjorn; O'Dwyer, Ian; Pukala, David] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kangaslahti, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 780 EP 781 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700407 ER PT B AU Schlecht, E Chattopadhyay, G Gill, J Lin, R Mehdi, I AF Schlecht, Erich Chattopadhyay, Goutam Gill, John Lin, Robert Mehdi, Imran GP IEEE TI New 600 GHz Balanced and Subharmonically Pumped Mixers with Reduced LO Power and State-of-the-Art Performance SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE C1 [Schlecht, Erich; Chattopadhyay, Goutam; Gill, John; Lin, Robert; Mehdi, Imran] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schlecht, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 819 EP 819 PG 1 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700428 ER PT B AU Pearson, JC Cooper, K Drouin, BJ AF Pearson, John C. Cooper, Ken Drouin, Brian J. GP IEEE TI Spectroscopic Detection, Fundamental Limits and System Considerations SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB Spectroscopic detection is the problem associated with detecting a small change in a large signal. This limit is most commonly associated with active measurements where absorption or loss is measured against frequency as in an absorption spectrometer. It results in rather different system considerations for active sensors that have been ignored or inaccurately treated in many claims of sensitivity in the submillimeter and THz regimes. C1 [Pearson, John C.; Cooper, Ken; Drouin, Brian J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pearson, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 824 EP 825 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700432 ER PT B AU Strekalov, DV Savchenkov, AA Matsko, AA Yu, N AF Strekalov, Dmitry V. Savchenkov, Anatoliy A. Matsko, Andrey A. Yu, Nan GP IEEE TI Towards microwave photon counting via frequency up-conversion SO 2008 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES, VOLS 1 AND 2 LA English DT Proceedings Paper CT 33rd International Conference on Infrared, Millimeter and Terahertz Waves CY SEP 15-19, 2008 CL Pasadena, CA SP IEEE AB We have demonstrated nonlinear optical upconversion of 100 GM signal into optical range using high-Q whispering gallery mode (WGM) resonators with quadratic nonlinearity. This approach has allowed us to achieve the record power conversion efficiency of 0.5% with as low as 16 mW of CW optical pump power. We furthermore show that by implementing the WGM resonator for the microwave as well as for the optical modes, the unity photon-number conversion efficiency can be in principle achieved. Combining such a converter with a state-of-the-art optical photon counter it will be possible to count the microwave photons whose frequency is as low as 0.1 THz, at room temperature. C1 [Strekalov, Dmitry V.; Savchenkov, Anatoliy A.; Matsko, Andrey A.; Yu, Nan] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Strekalov, DV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2119-0 PY 2008 BP 862 EP 863 PG 2 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BIV57 UT WOS:000263160700453 ER PT B AU Woo, SS Cheng, MK AF Woo, Simon S. Cheng, Michael K. GP IEEE TI Prioritized LT codes SO 2008 42ND ANNUAL CONFERENCE ON INFORMATION SCIENCES AND SYSTEMS, VOLS 1-3 LA English DT Proceedings Paper CT 42nd Annual Conference on Information Sciences and Systems CY MAR 19-21, 2008 CL Princeton, NJ SP IEEE AB It is common in data transmissions that some information is more important than others. This is especially true in space communications where mission critical information or science data are high priority. In this work, we propose a simple yet constructive scheme to send high priority data reliably and efficiently using Luby Transform (LT) codes. The new proposed scheme modifies the conventional LT encoder to send high priority data as a degree I and 2 so that high priority data can be quickly resolved and very likely recovered before a decoder stops. Preliminary results show that a carefully designed degree distribution of high priority data increases the likelihood of receiving high priority information while having negligible performance impact on data with lower priority. The performance of the proposed scheme is evaluated and compared with the conventional LT approach with the same parameters under a range of erasure error rates. C1 [Woo, Simon S.; Cheng, Michael K.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Woo, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Simon.S.Woo@jpl.nasa.gov; Michael.K.Cheng@jpl.nasa.gov NR 8 TC 6 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2246-3 PY 2008 BP 568 EP 573 DI 10.1109/CISS.2008.4558589 PG 6 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIE60 UT WOS:000258931600106 ER PT S AU Michel, T Hensley, S AF Michel, Thierry Hensley, Scott BE Matthews, MB TI Wavenumber Domain Focusing of Squinted SAR Data with a Curved Orbit Geometry SO 2008 42ND ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS, VOLS 1-4 SE CONFERENCE RECORD OF THE ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS LA English DT Proceedings Paper CT 42nd Asilomar Conference on Signals, Systems and Computers CY OCT 26-29, 2008 CL Pacific Grove, CA SP Naval Postgrad Sch, ATK Mission Res, IEEE Signal Proc Soc ID SEISMIC MIGRATION AB Synthetic Aperture Radar systems provide raw data that need focusing to achieve full-resolution imaging. Current SAR applications, including interferometry, require accurate, phase-preserving, and precisely co-registered coherent images over large ground swaths with the highest achievable resolution. In addition to these challenges, stripmap SAR data may be acquired with an off-broadside (squinted) geometry, either by design or through platform motion. The precise batch focusing of these large aperture and wide bandwidth data sets is known to require a 2D frequency processing approach. The standard wave domain focusing algorithm, however, is only exact for data acquired on a rectilinear trajectory. We investigate a generalization of the standard omega-k focusing formulation that allows curved data acquisition tracks. The new formulation can be used in conjunction with a known extension for conical, squinted imaging grids. The approximations necessary to allow the generalized geometry are analysed to determines the range of applicability of the proposed algorithm. The theory is validated using data simulated with parameters similar to the UAVSAR L-band SAR system. C1 [Michel, Thierry; Hensley, Scott] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Michel, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Thierry.Michel@jpl.nasa.gov NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1058-6393 BN 978-1-4244-2940-0 J9 CONF REC ASILOMAR C PY 2008 BP 492 EP 496 DI 10.1109/ACSSC.2008.5074454 PG 5 WC Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BNH24 UT WOS:000274551000094 ER PT S AU Brockman, J Li, S Kogge, P Kashyap, A Mojarradi, M AF Brockman, Jay Li, Sheng Kogge, Peter Kashyap, Amit Mojarradi, Mohammad GP IEEE TI Design of a mask-programmable memory/multiplier array using G4-FET technology SO 2008 45TH ACM/IEEE DESIGN AUTOMATION CONFERENCE, VOLS 1 AND 2 SE Design Automation Conference DAC LA English DT Proceedings Paper CT 45th ACM/IEEE Design Automation Conference CY JUN 08-13, 2008 CL Anaheim, CA SP ACM, IEEE DE G4-FET; gate array AB A G4-FET is a 4 gate transistor that combines both JFET and MOS characteristics in a single device that may be fabricated in a standard silicon-on-insulator (SOI) process. In doing so, it enables the conducting channel to be controlled vertically through MOS gates, as well as horizontally, through junction gates. Further, depending upon how it is biased, a single G4-FET can serve as either a not-majority logic gate or as a charge storage-based memory cell. This unique device offers tremendous potential for innovative gate arrays, where real estate can be traded-off between logic and memory functions. In this paper, we take a first look at a mask-programmable G4-FET array that depending upon metal personalization, can function either as a DRAM array or a multiplier. C1 [Brockman, Jay; Li, Sheng; Kogge, Peter] Univ Notre Dame, Notre Dame, IN 46556 USA. [Kashyap, Amit] Adv Micro Devices Inc, Austin, TX USA. [Mojarradi, Mohammad] NASA, Jet Prop Lab, Pasadena, CA USA. RP Brockman, J (reprint author), Univ Notre Dame, Notre Dame, IN 46556 USA. EM jbb@nd.com; sli2@nd.com; kogge@nd.com; Amit.Kashyap@amd.com; Mohammad.Mojarradi@jpl.nasa.gov FU AFRL; DARPA [FA8601-04-D] FX This work was supported by AFRL and DARPA under contract FA8601-04-D. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0738-100X BN 978-1-60558-115-6 J9 DES AUT CON PY 2008 BP 337 EP + PG 2 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIE57 UT WOS:000258930200065 ER PT S AU Kuehimann, A Rutenbar, RA Bose, A Manning, RM Corman, DE Newman, A AF Kuehimann, Andreas Rutenbar, Rob A. Bose, Anjan Manning, Robert M. Corman, David E. Newman, Anna GP IEEE TI Verifying really complex systems: On earth and beyond SO 2008 45TH ACM/IEEE DESIGN AUTOMATION CONFERENCE, VOLS 1 AND 2 SE Design Automation Conference DAC LA English DT Proceedings Paper CT 45th ACM/IEEE Design Automation Conference CY JUN 08-13, 2008 CL Anaheim, CA SP ACM, IEEE DE verification; power grids; avionics; space vehicles; Mars Exploration Rover; bald lemurs; computer animation; rendering software C1 [Kuehimann, Andreas] Cadence Res Lab, Berkeley, CA USA. [Bose, Anjan] Washington State Univ, Pullman, WA 99164 USA. [Corman, David E.] Beoing Phantom Works, St Louis, MO USA. [Rutenbar, Rob A.] Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. [Manning, Robert M.] NASA, Jet Prop Lab, Pasadena, CA USA. [Newman, Anna] DreamWorks Animat, Redwood City, CA USA. RP Kuehimann, A (reprint author), Cadence Res Lab, Berkeley, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0738-100X BN 978-1-60558-115-6 J9 DES AUT CON PY 2008 BP 552 EP + PG 2 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIE57 UT WOS:000258930200108 ER PT S AU Stoica, A Kuhlman, M Assad, C Keymeulen, D AF Stoica, Adrian Kuhlman, Michael Assad, Chris Keymeulen, Didier GP IEEE TI Developing Humanoid Robots for Real-World Environments SO 2008 8TH IEEE-RAS INTERNATIONAL CONFERENCE ON HUMANOID ROBOTS (HUMANOIDS 2008) SE IEEE-RAS International Conference on Humanoid Robots LA English DT Proceedings Paper CT 8th IEEE/RAS International Conference on Humanoid Robots CY DEC 01-03, 2008 CL Daejeon, SOUTH KOREA SP IEEE, RAS ID STATE ESTIMATION AB Humanoids are steadily improving in appearance and functionality demonstrated in controlled environments. To address the challenges of operation in the real-world, researchers have proposed the use of brain-inspired architectures for robot control, and the use of robot learning techniques that enable the robot to acquire and tune skills and behaviours. In the first part of the paper we introduce new concepts and results in these two areas. First, we present a cerebellum-inspired model that demonstrated efficiency in the sensory-motor control of anthropomorphic arms, and in gait control of dynamic walkers. Then, we present a set of new ideas related to robot learning, emphasizing the importance of developing teaching techniques that support learning. In the second part of the paper we propose the use in robotics of the iterative and incremental development methodologies, in the context of practical task-oriented applications. These methodologies promise to rapidly reach system-level integration, and to early identify system-level weaknesses to focus on. We apply this methodology in a task targeting the automated assembly of a modular structure using HOAP-2. We confirm this approach led to rapid development of a end-to-end capability, and offered guidance on which technologies to focus on for gradual improvement of a complete functional system. It is believed that providing Grand Challenge type milestones in practical task-oriented applications accelerates development. As a meaningful target in short-mid term we propose the 'IKEA Challenge', aimed at the demonstration of autonomous assembly of various pieces of furniture, from the box, following included written/drawn instructions. C1 [Stoica, Adrian; Assad, Chris; Keymeulen, Didier] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. [Kuhlman, Michael] Rensselaer Polytech Inst, Troy, NY 12181 USA. RP Stoica, A (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM adrian.stoica@jpl.nasa.gov FU California Institute of Technology; National Aeronautics and Space Administration; JPL Advanced Concepts Program Office; NASA's CICT/ITSR Revolutionary Computing program; DARPA FX The work presented in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology for the National Aeronautics and Space Administration. The following personnel and students participated: John Myers, Aaron Schon, Jason Newton, Brent Allen, Alex Sanchez, Sal Trujillo, Sanjay Dastoor, Ling Xu. The work was funded by the JPL Advanced Concepts Program Office, managed by Dr. Neville Marzwell, NASA's CICT/ITSR Revolutionary Computing program, and by DARPA, under a program managed by Dr. Larry Jackel. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 2164-0572 BN 978-1-4244-2821-2 J9 IEEE-RAS INT C HUMAN PY 2008 BP 715 EP + PG 2 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Robotics SC Computer Science; Engineering; Robotics GA BJR82 UT WOS:000267052300110 ER PT B AU Ayaz, S Bauer, C Eddy, WM Arnal, F AF Ayaz, Serkan Bauer, Christian Eddy, Wesley M. Arnal, Fabrice GP IEEE TI NEMO Route Optimization Solution Space Analysis and Evaluation Criteria for Aviation SO 2008 8TH INTERNATIONAL CONFERENCE ON ITS TELECOMMUNICATIONS, PROCEEDINGS LA English DT Proceedings Paper CT 8th International Conference on Intelligent Transport System Telecommunications CY OCT 22-24, 2008 CL Phuket, THAILAND SP IEEE, NECTEC, NiCT, YRP, IPS, ITS AB The aviation community is currently designing an IPv6-based aeronautical telecommunication network (ATN/IP), which aims to provide seamless communication services to the cockpit users. One of the challenging tasks in the ATN/IP is the scalable mobility management of aircraft as entire networks in motion. We have investigated possible IPv6-based network mobility (NEMO) route optimization (RO) solutions for safety related and non-safety related services. We have also presented realistic ATN/IP topology and a set of evaluation criteria for a better analysis of the possible solutions. Our investigations showed that AIR-based RO solutions are more suited than MNN-based RO solutions to the aeronautical environment for the near future. We have also realized that multiple MR-based RO solutions could also be used together for a better end-to-end route optimization. C1 [Ayaz, Serkan; Bauer, Christian] German Aerosp Ctr, D-82234 Wessling, Germany. [Eddy, Wesley M.] NASA, Glenn Res Ctr, Cleveland, OH USA. [Arnal, Fabrice] Thales Alenia Space 26, F-33787 Toulouse 1, France. RP Ayaz, S (reprint author), German Aerosp Ctr, D-82234 Wessling, Germany. EM serkan.ayaz@dlr.de; christian.bauer@dlr.de; weddy@grc.nasa.gov; fabrice.arnal@thalesaleniaspace.com FU European Commission through the NEWSKY project [37160] FX This work is partially funded by the European Commission through the NEWSKY project under contract no. 37160 NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2857-1 PY 2008 BP 139 EP + DI 10.1109/ITST.2008.4740244 PG 2 WC Telecommunications; Transportation Science & Technology SC Telecommunications; Transportation GA BJC55 UT WOS:000264749600027 ER PT S AU Boskovic, JD Jackson, JA Mehra, RK Nguyen, NT AF Boskovic, Jovan D. Jackson, Joseph A. Mehra, Raman K. Nguyen, Nhan T. GP IEEE TI Adaptive fault tolerant control design for a model of DC-X dynamics SO 2008 AMERICAN CONTROL CONFERENCE, VOLS 1-12 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT American Control Conference 2008 CY JUN 11-13, 2008 CL Seattle, WA SP IEEE ID FLIGHT CONTROL AB A Failure Detection, Identification and Reconfiguration (FDIR) control scheme is developed for a dynamic model of the Delta Clipper-Experimental (DC-X) single stage to orbit rocket concept. The six degree of freedom, redundantly actuated model provides a well-suited test case for designing a fault-tolerant controller for actuators with different response rates. the reconfigurable controller maintains the desired closed-loop performance. Robustness of the system was demonstrated under a large number of different single and multiple failure cases. C1 [Boskovic, Jovan D.; Jackson, Joseph A.; Mehra, Raman K.] Sci Syst Co Inc, 500 W Cummings Pk,Suite 3000, Woburn, MA 01801 USA. [Nguyen, Nhan T.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Boskovic, JD (reprint author), Sci Syst Co Inc, 500 W Cummings Pk,Suite 3000, Woburn, MA 01801 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 978-1-4244-2078-0 J9 P AMER CONTR CONF PY 2008 BP 1046 EP + DI 10.1109/ACC.2008.4586630 PG 2 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIG00 UT WOS:000259261500175 ER PT S AU Aldrich, JB Badescu, M Jones, C Bar-Cohen, Y AF Aldrich, J. B. Badescu, M. Jones, C. Bar-Cohen, Y. GP IEEE TI Resonance seeking control in an event-triggered discrete-time domain SO 2008 AMERICAN CONTROL CONFERENCE, VOLS 1-12 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference 2008 CY JUN 11-13, 2008 CL Seattle, WA SP IEEE AB Resonance tracking control of oscillatory plants whose natural frequency is unknown is investigated from a Lyapunov stability perspective. In particular, an event-triggered discrete-time system is investigated for this purpose. The proposed resonance tuner is time-synchronized with periodic sampling of the harmonic plant's output to ensure that an analytical relationship exists between the period of the driving squarewave and the tracking error. This relation defines a class of discrete-time nonlinear systems whose origin, is shown to be asymptotically stable. C1 [Aldrich, J. B.; Badescu, M.; Jones, C.; Bar-Cohen, Y.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Aldrich, JB (reprint author), CALTECH, Jet Prop Lab, MS 67-119, Pasadena, CA 91109 USA. NR 20 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 978-1-4244-2078-0 J9 P AMER CONTR CONF PY 2008 BP 2892 EP 2896 DI 10.1109/ACC.2008.4586934 PG 5 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIG00 UT WOS:000259261502044 ER PT S AU Nguyen, NT Boskovic, JD AF Nguyen, Nhan T. Boskovic, Jovan D. GP IEEE TI Bounded linear stability margin analysis of nonlinear hybrid adaptive control SO 2008 AMERICAN CONTROL CONFERENCE, VOLS 1-12 SE Proceedings of the American Control Conference LA English DT Proceedings Paper CT American Control Conference 2008 CY JUN 11-13, 2008 CL Seattle, WA SP IEEE AB This paper presents a bounded linear stability analysis for a hybrid adaptive control that blends both direct and indirect adaptive control. Stability and convergence of nonlinear adaptive control are analyzed using an approximate linear equivalent system. A stability margin analysis shows that a large adaptive gain can lead to a reduced phase margin. This method can enable metrics-driven adaptive control whereby the adaptive gain is adjusted to meet stability margin requirements. C1 [Nguyen, Nhan T.] NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. [Boskovic, Jovan D.] Sci Syst Co Inc, Woburn, MA 01801 USA. RP Nguyen, NT (reprint author), NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. EM Nhan.T.Nguyen@nasa.gov; Jovan.Boskovic@ssci.com NR 9 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 978-1-4244-2078-0 J9 P AMER CONTR CONF PY 2008 BP 3638 EP + DI 10.1109/ACC.2008.4587058 PG 2 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIG00 UT WOS:000259261502168 ER PT B AU Bradley, AT Evans, WC Reed, JL Shimp, SK Fitzpatrick, FD AF Bradley, Arthur T. Evans, William C. Reed, Joshua L. Shimp, Samuel K., III Fitzpatrick, Fred D. GP IEEE TI TEM cell testing of cable noise reduction techniques from 2 MHz to 200 MHz - Part 1 SO 2008 ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 19TH INTERNATIONAL ZURICH SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1 AND 2 LA English DT Proceedings Paper CT Asia-Pacific Symposium on Electromagnetic Compatibility/19th International Zurich Symposium on Electromagnetic Compatibility CY MAY 19-23, 2008 CL Singapore, SINGAPORE AB This paper presents empirical results of cable noise reduction techniques as demonstrated in a TEM cell operating with radiated fields from 2 - 200 MHz. It is the first part of a two-paper series. This first paper discusses cable types and shield connections. In the second paper, the effects of load and source resistances and chassis connections are examined. For each topic, well established theories are compared to data from a real-world physical system. Finally, recommendations for minimizing cable susceptibility (and thus cable emissions) are presented. C1 [Bradley, Arthur T.; Evans, William C.; Reed, Joshua L.; Shimp, Samuel K., III; Fitzpatrick, Fred D.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bradley, AT (reprint author), NASA, Langley Res Ctr, 5 N Dryden,MS488, Hampton, VA 23681 USA. EM arthur.t.bradley@nasa.gov; cce032000@utdallas.edu; jreed258@ignatius.wju.edu; sshimp@vt.edu; fred.d.fitzpatrick@nasa.gov NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-981-08-0628-6 PY 2008 BP 610 EP 613 DI 10.1109/APEMC.2008.4559949 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BID20 UT WOS:000258515300154 ER PT B AU Bradley, AT Evans, WC Reed, JL Shimp, SK Fitzpatrick, FD AF Bradley, Arthur T. Evans, William C. Reed, Joshua L. Shimp, Samuel K., III Fitzpatrick, Fred D. GP IEEE TI TEM cell testing of cable noise reduction techniques from 2 MHz to 200 MHz - Part 2 SO 2008 ASIA-PACIFIC SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY AND 19TH INTERNATIONAL ZURICH SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1 AND 2 LA English DT Proceedings Paper CT Asia-Pacific Symposium on Electromagnetic Compatibility/19th International Zurich Symposium on Electromagnetic Compatibility CY MAY 19-23, 2008 CL Singapore, SINGAPORE AB This paper presents empirical results of cable noise reduction techniques as demonstrated in a TEM cell operating with radiated fields from 2 - 200 MHz. It is the second part of a two-paper series. The first paper discussed cable types and shield connections. In this second paper, the effects of load and source resistances and chassis connections are examined. For each topic, well established theories are compared to data from a real-world physical system. Finally, recommendations for minimizing cable susceptibility (and thus cable emissions) are presented. C1 [Bradley, Arthur T.; Evans, William C.; Reed, Joshua L.; Shimp, Samuel K., III; Fitzpatrick, Fred D.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Bradley, AT (reprint author), NASA, Langley Res Ctr, 5 N Dryden,MS488, Hampton, VA 23681 USA. EM arthur.t.bradley@nasa.gov; cce032000@utdallas.edu; jreed258@ignatius.wju.edu; sshimp@vt.edu; fred.d.fitzpatrick@nasa.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-981-08-0628-6 PY 2008 BP 614 EP 617 DI 10.1109/APEMC.2008.4559950 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BID20 UT WOS:000258515300155 ER PT B AU Allan, GR AF Allan, Graham R. GP IEEE TI Evidence for Optically Induced Heating of the GLAS/ICESAT Doubler Crystal SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) CY MAY 04-09, 2008 CL San Jose, CA AB Numerical modeling results of optically induced heating of the GLAS doubler explain the performance degradation in output energy of laser-I and II and partially laser-III and are consistent with the on-orbit telemetry. (C)2008 Optical Society of America C1 NASA, Goddard Space Flight Ctr, Sigma Space Corp, Greenbelt, MD 20771 USA. RP Allan, GR (reprint author), NASA, Goddard Space Flight Ctr, Sigma Space Corp, MC 694, Greenbelt, MD 20771 USA. EM graham.allan@gsfc.nasa.gov RI Allan, Graham/D-3905-2013 NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 216 EP 217 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400109 ER PT B AU Riris, H Sun, XL Cavanaugh, JF Ramos-Izquierdo, L Liiva, P Jackson, GB Schmidt, S McGarry, J Smith, DE AF Riris, Haris Sun, Xiaoli Cavanaugh, John F. Ramos-Izquierdo, Luis Liiva, Pete Jackson, Glenn B. Schmidt, Steve McGarry, Jan Smith, David E. GP IEEE TI The Lunar Orbiter Laser Altimeter (LOLA) on NASA's Lunar Reconnaissance Orbiter (LRO) Mission SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference CY MAY 04-09, 2008 CL San Jose, CA AB We describe the Lunar Orbiter Laser Altimeter instrument on NASA's Lunar Reconnaissance Orbiter mission, scheduled to launch in October 2008, which will provide a precise lunar high-resolution global topographic map using laser altimetry. (C) 2008 Optical Society of America C1 [Riris, Haris; Sun, Xiaoli; Cavanaugh, John F.; Ramos-Izquierdo, Luis; Liiva, Pete; Jackson, Glenn B.; Schmidt, Steve; McGarry, Jan; Smith, David E.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Riris, H (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Haris.Riris-1@nasa.gov RI Sun, Xiaoli/B-5120-2013; McGarry, Jan/C-4109-2013; Riris, Haris/D-1004-2013 NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 672 EP 673 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400337 ER PT B AU Yu, AW Novo-Gradac, AM Shaw, GB Li, SX Krebs, DC Ramos-Izquierdo, LA Unger, G Lukemire, A AF Yu, Anthony W. Novo-Gradac, Anne-Marie Shaw, George B. Li, Steven X. Krebs, Danny C. Ramos-Izquierdo, Luis A. Unger, Glenn Lukemire, Alan GP IEEE TI Laser Transmitter for the Lunar Orbit Laser Altimeter (LOLA) Instrument SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) CY MAY 04-09, 2008 CL San Jose, CA AB We present final configuration of the space flight laser transmitter as delivered to the LOLA instrument. The laser consists of two oscillators on a single bench, each capable of providing one billion plus shots. (C) 2008 Optical Society of America C1 [Yu, Anthony W.; Novo-Gradac, Anne-Marie; Shaw, George B.; Li, Steven X.; Krebs, Danny C.] NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, MC554, Greenbelt, MD 20771 USA. [Ramos-Izquierdo, Luis A.] NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. [Unger, Glenn] NASA, Goddard Space Flight Ctr, Microelect & Signal Processing Branch, Greenbelt, MD 20771 USA. [Lukemire, Alan] Space Power Elect Inc, Kathleen, GA 31047 USA. RP Yu, AW (reprint author), NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, MC554, Greenbelt, MD 20771 USA. FU LOLA science team FX The authors acknowledge the support of the LOLA science team, especially David E. Smith (PI), Maria Zuber (PI), the LOLA instrument team, Glenn Jackson (instrument manager), Ron Zellar (deputy instrument manager), John Cavanaugh (system engineer) and Larry Ramsey (contamination lead). NR 3 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 674 EP + PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400338 ER PT B AU Bai, YX Yu, JR Trieu, B Petros, M Petzar, P Lee, H Singh, U AF Bai, Yingxin Yu, Jirong Trieu, Bo Petros, M. Petzar, Paul Lee, Hyung Singh, U. GP IEEE TI Conductively cooled Ho:Tm:LuLiF laser amplifier SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) CY MAY 04-09, 2008 CL San Jose, CA AB A conductively-cooled Ho:Tm:LuLiF laser head can amplify 80mJ/340ns probe pulses into 400mJ when the pump pulse energy is close to amplified spontaneous emission (ASE) threshold, 5.6J. For a small signal, the double-pass amplification exceeds 25. (C) 2008 Optical Society of America C1 [Bai, Yingxin] Sci Syst & Applicat Inc, 1 Enterprise Pkwy, Hampton, VA 23666 USA. [Yu, Jirong; Trieu, Bo; Singh, U.] NASA, Langley Res Ctr, Hampton, VA 23666 USA. [Petros, M.] Sci & Technol Corp, Hampton, VA 23666 USA. [Petzar, Paul; Lee, Hyung] Nat Inst Aerosp, Hampton, VA 23666 USA. RP Bai, YX (reprint author), Sci Syst & Applicat Inc, 1 Enterprise Pkwy, Hampton, VA 23666 USA. EM yingxin.bai-1@nasa.gov NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 1276 EP + PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400640 ER PT B AU Kim, S Sherwin, MS Zimmerman, JD Gossard, AC Focardi, P Wu, DH AF Kim, Sangwoo Sherwin, Mark S. Zimmerman, Jeramy D. Gossard, Arthur C. Focardi, Paolo Wu, Dong Ho GP IEEE TI Room Temperature Terahertz Detection based on Electron Plasma Resonance in an Antenna-Coupled GaAs MESFET SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) CY MAY 04-09, 2008 CL San Jose, CA AB Plasma resonance of electrons was observed in an Antenna-Coupled GaAs Metal-Semiconductor-Field-Effect-Transistor (MESFET) by sweeping bias voltages. This resonant absorption was used to realize a room temperature terahertz detector. (C)2008 Optical Society of America C1 [Kim, Sangwoo; Sherwin, Mark S.] Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. [Zimmerman, Jeramy D.; Gossard, Arthur C.] Univ Calif Santa Barbara, Dept Math, Santa Barbara, CA 93106 USA. [Focardi, Paolo] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Wu, Dong Ho] Naval Res Lab, Washington, DC 20375 USA. RP Kim, S (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. EM swkim@physics.ucsb.edu; sherwin@physics.ucsb.edu RI Zimmerman, Jeramy/C-2273-2009 OI Zimmerman, Jeramy/0000-0001-8936-5345 FU NSF-DMR [0703925]; Naval Research Lab FX Work supported by NSF-DMR 0703925 and Naval Research Lab. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 1728 EP + PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400867 ER PT B AU Mansour, K Hill, CJ Qlu, YM Yang, RQ AF Mansour, Kamjou Hill, Cory J. Qlu, Yueming Yang, Rui Q. GP IEEE TI Dual-Wavelength Interband Cascade Lasers in Mid-infrared Spectral Region SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) CY MAY 04-09, 2008 CL San Jose, CA ID THERMOELECTRIC COOLER TEMPERATURES AB We report the world-first successful demonstration of widely spaced dual wavelength interband cascade lasers operating simultaneously in continuous wave near 3.5 and 4.5 microns. C1 [Mansour, Kamjou; Hill, Cory J.; Qlu, Yueming] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Yang, Rui Q.] Univ Oklahoma, Sch Elect & Comp Engn, Norman, OK 73019 USA. RP Mansour, K (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM Kamjou.mansour@JPL.nasa.gov NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 1756 EP + PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498400881 ER PT B AU Grudinin, IS Matsko, AB Maleki, L AF Grudinin, Ivan S. Matsko, Andrey B. Maleki, Lute GP IEEE TI Crystalline Cavities for Quantum and Nonlinear Optics SO 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9 LA English DT Proceedings Paper CT Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference CY MAY 04-09, 2008 CL San Jose, CA AB We present crystalline whispering gallery mode resonators (WGMR) operating as the efficient Raman lasers. Fundamental limitations on optical quality (Q) factor are discussed. A new resonant scattering phenomenon is observed. (C)2008 Optical Society of America C1 [Grudinin, Ivan S.; Matsko, Andrey B.; Maleki, Lute] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grudinin, IS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM grudinin@caltech.edu NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-55752-859-9 PY 2008 BP 2707 EP 2707 PG 1 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BIL52 UT WOS:000260498401344 ER PT B AU Llombart, N Bryllert, T Chattopadhyay, G Cooper, K Dengler, R Gill, J McNary, AJ Mehdi, I Schlecht, E Skalare, A Siegel, PH AF Llombart, Nuria Bryllert, Tomas Chattopadhyay, Goutam Cooper, Ken Dengler, Robert Gill, John McNary, Andrew J. Mehdi, Imran Schlecht, Erich Skalare, Anders Siegel, Peter H. GP IEEE TI THz Heterodyne Imaging Applications, Instruments and Directions SO 2008 EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3 LA English DT Proceedings Paper CT 38th European Microwave Conference CY OCT 27-31, 2008 CL Amsterdam, NETHERLANDS ID TERAHERTZ TECHNOLOGY AB This paper briefly discusses some of the RF heterodyne imaging applications and instruments that are being developed and deployed for the THz frequency regime. After more than three decades of academic research the THz equivalent of the IR camera is still confined to proposals. However, as the component technology matures and new instruments emerge, interest in applications has followed. Some of the early imaging array concepts are now being revisited and new ideas are coming into the light. C1 [Llombart, Nuria; Bryllert, Tomas; Chattopadhyay, Goutam; Cooper, Ken; Dengler, Robert; Gill, John; McNary, Andrew J.; Mehdi, Imran; Schlecht, Erich; Skalare, Anders; Siegel, Peter H.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Llombart, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-3794-8 PY 2008 BP 758 EP 761 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BJE19 UT WOS:000265089100193 ER PT B AU U-yen, K Wollack, EJ AF U-yen, Kongpop Wollack, Edward J. GP IEEE TI Compact Planar Microwave Blocking Filter SO 2008 EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3 LA English DT Proceedings Paper CT 38th European Microwave Conference CY OCT 27-31, 2008 CL Amsterdam, NETHERLANDS AB This paper proposes a technique to design a compact planar broadband microwave blocking filter. The filter is constructed from multiple sections of bandstop filters with means to control radiation loss. As a result, the filter has small physical size and provides multi-decade of suppression frequency bandwidth. The total length is less than half-wavelength long at the 3-dB corner frequency of 1.45 GHz. The experimental results show that the microstrip microwave blocking filter can provide an attenuation of more than 70 dB from 7 GHz to 39.5GHz with the total DC capacitance of less than 23 pF. C1 [U-yen, Kongpop; Wollack, Edward J.] NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. RP U-yen, K (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. EM kongpop.u-yen-l@nasa.gov; edward.j.wollack@nasa.gov RI Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-3794-8 PY 2008 BP 1087 EP 1090 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BJE19 UT WOS:000265089100276 ER PT B AU Rincon, RF AF Rincon, Rafael F. GP IEEE TI Reconfigurable L-Band Radar SO 2008 EUROPEAN RADAR CONFERENCE SE European Radar Conference-EuRAD LA English DT Proceedings Paper CT 5th European Radar Conference CY OCT 30-31, 2008 CL Amsterdam, NETHERLANDS AB The reconfigurable L-Band radar is an ongoing development at NASA/GSFC that exploits the capability inherently in phased array radar systems with a state-of-the-art data acquisition and real-time processor in order to enable multimode measurement techniques in a single radar architecture. The development leverages on the L-Band Imaging Scatterometer, a radar system designed for the development and testing of new radar techniques; and the custom-built DBSAR processor, a highly reconfigurable, high speed data acquisition and processing system. The radar modes currently implemented include scatterometer, synthetic aperture radar, and altimetry; and plans to add new modes such as radiometry and bi-static GNSS signals are being formulated. This development is aimed at enhancing the radar remote sensing capabilities for airborne and spaceborne applications in support of Earth Science and planetary exploration This paper describes the design of the radar and processor systems, explains the operational modes, and discusses preliminary measurements and future plans. C1 NASA, Goddard Space Flight Ctr, Washington, DC 20546 USA. RP Rincon, RF (reprint author), NASA, Goddard Space Flight Ctr, Washington, DC 20546 USA. EM rafael.rincon@nasa.gov NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-2-8748-7009-5 J9 EUROP RADAR CONF PY 2008 BP 104 EP 107 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BMD29 UT WOS:000271901200027 ER PT S AU Chen, TR Hsin, W Chen, SB Chen, P Erlig, H AF Chen, T. R. Hsin, W. Chen, S. B. Chen, P. Erlig, H. GP IEEE TI ULTRA WIDE TEMPERATURE OPERATION OF DFB LASERS SO 2008 IEEE 20TH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS (IPRM) SE International Conference on Indium Phosphide and Related Materials LA English DT Proceedings Paper CT 20th International Conference on Indium Phosphide and Related Materials CY MAY 25-29, 2008 CL Versailles, FRANCE SP IEEE DE DFB; lasers; laser diodes; extended temperature; 1310nm; 1490nm ID DISTRIBUTED-FEEDBACK LASERS; THRESHOLD CURRENT; RANGE AB Single mode operation of 1310nm DFB lasers over a record wide temperature range, from -70 degrees C to 110 degrees C, has been demonstrated. Less than 2dB optical power variation was realized over most of the temperature range. C1 [Chen, T. R.; Hsin, W.; Chen, S. B.; Chen, P.] Archcom Technol Inc, Azusa, CA 91702 USA. [Erlig, H.] Photon & Laser Applicat Grp, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chen, TR (reprint author), Archcom Technol Inc, Azusa, CA 91702 USA. EM dchen@archcomtech.com NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8669 BN 978-1-4244-2258-6 J9 CONF P INDIUM PHOSPH PY 2008 BP 165 EP + PG 2 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BKB63 UT WOS:000267695700047 ER PT S AU Lai, R Deal, WR Mei, XB Yoshida, W Lee, J Dang, L Wang, J Kim, YM Liu, PH Radisic, V Lange, M Gaier, T Samoska, L Fung, A AF Lai, R. Deal, W. R. Mei, X. B. Yoshida, W. Lee, J. Dang, L. Wang, J. Kim, Y. M. Liu, P. H. Radisic, V. Lange, M. Gaier, T. Samoska, L. Fung, A. GP IEEE TI Fabrication of InP HEMT Devices with Extremely High Fmax SO 2008 IEEE 20TH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE AND RELATED MATERIALS (IPRM) SE International Conference on Indium Phosphide and Related Materials LA English DT Proceedings Paper CT 20th International Conference on Indium Phosphide and Related Materials CY MAY 25-29, 2008 CL Versailles, FRANCE SP IEEE AB In this paper, we present the latest advancements of short gate length InGaAs/InAIAs/InP High Electron Mobility Transistor (InP HEMT) devices that have achieved extremely high extrapolated Fmax above 1 THz. The high Fmax is validated through the first demonstrations of sub-MMW MMICs (s-MMICs) based on these devices including the highest fundamental transistor oscillator MMIC at 347 GHz and the highest gain greater than 15 dB (greater than 5 dB per stage) at 340 GHz. C1 [Lai, R.; Deal, W. R.; Mei, X. B.; Yoshida, W.; Lee, J.; Dang, L.; Wang, J.; Kim, Y. M.; Liu, P. H.; Radisic, V.; Lange, M.] Northrop Grumman Space Technol, 1 Space Pk, Redondo Beach, CA 90278 USA. [Gaier, T.; Samoska, L.; Fung, A.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Lai, R (reprint author), Northrop Grumman Space Technol, 1 Space Pk, Redondo Beach, CA 90278 USA. FU DARPA SWIFT Program; Army Research Laboratory under ARL [W911QX-06-C-0050]; National Aeronautics and Space Administration FX This work was supported by DARPA SWIFT Program (Dr. Mark Rosker) and Army Research Laboratory (Dr. H. Alfred Hung) under the ARL Contract No: W911QX-06-C-0050. The authors would like to thank Richard To, Stella Makishi, Jeff Coakley, Danny Li, Patti Oliver, Tim Naeole, Mike Barsky, Jansen Uyeda, Weidong Liu, Patrick Chin, Abdullah Cavus and members of NGST microelectronics laboratory and RF design team for their technical contributions. The authors would also like to thank Phillip Chang (BAH), Milton Feng (UIUC), Ron Grundbacher (Swiss ETH), Aaron Oki (NGST), Reynold Kagiwada (NGST), Dwight Streit (NGST), Dave Farkas (NGST) and the late Barry Allen for their support, advice and reference data. This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 6 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8669 BN 978-1-4244-2258-6 J9 CONF P INDIUM PHOSPH PY 2008 BP 592 EP + PG 2 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BKB63 UT WOS:000267695700166 ER PT S AU Lesser, E Schaeps, T Haikonen, POA Jorgensen, C AF Lesser, Emmanuel Schaeps, Tim Haikonen, Peniti O. A. Jorgensen, Charles GP IEEE TI ASSOCIATIVE NEURAL NETWORKS FOR MACHINE CONSCIOUSNESS: IMPROVING EXISTING AI TECHNOLOGIES SO 2008 IEEE 25TH CONVENTION OF ELECTRICAL AND ELECTRONICS ENGINEERS IN ISRAEL, VOLS 1 AND 2 SE IEEE Convention of Electrical and Electronics Engineers in Israel LA English DT Proceedings Paper CT 47th AIAA Aerospace Sciences Meeting and Exhibit Including the New Horizons Forum and Aerospace Exposition CY JAN 05-08, 2009 CL Orlando, FL SP AIAA DE Neural networks; artificial intelligence; speech recognition; electromyography; random number generation AB In this research we look at ways for improving existing AI techniques by the use of associative neural networks, proposed by Haikonen for machine consciousness. We find that all examined technologies do profit from such an approach: speech recognition, emotion recognition in speech, EMG data analysis for multilingual speech processing, the simulation of bistable perception and the generation of random numbers. EMG data analysis for multilingual speech processing (silent speech recognition) is selected as the main example in this paper for its simple yet complete architecture. We discuss the development of a test bench and give an overview of results obtained. C1 [Lesser, Emmanuel; Schaeps, Tim] Univ Coll Antwerp, Fac Appl Engn, Dept Elect ICT, Paardenmarkt 92, B-2000 Antwerp, Belgium. [Haikonen, Peniti O. A.] Nokia Res Ctr, FI-00045 Helsinki, Finland. [Jorgensen, Charles] NASA, Ames Res Ctr, Neuro Engn Lab, Moffett Field, CA 94035 USA. RP Lesser, E (reprint author), Univ Coll Antwerp, Fac Appl Engn, Dept Elect ICT, Paardenmarkt 92, B-2000 Antwerp, Belgium. NR 23 TC 1 Z9 1 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0899-6156 BN 978-1-4244-2481-8 J9 IEEE CONV EL ELECT I PY 2008 BP 11 EP + DI 10.1109/EEEI.2008.4736701 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BJE01 UT WOS:000265073200003 ER PT S AU Harrison, DA Ambrose, R Bluethmann, B Junkin, L AF Harrison, Dan A. Ambrose, Robert Bluethmann, Bill Junkin, Lucien GP IEEE TI Next generation rover for lunar exploration SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB As NASA refines its plans for the return of humans to the lunar surface, it becomes very clear that surface mobility will be critical to outpost buildup and exploration activities. NASA's Exploration Technology Development Program is investing in a broad range of surface mobility projects. Within this range of projects falls a rover vehicle, capable of moving suited crew members and cargo. A prototype, known as Chariot has been developed. This prototype vehicle is a multipurpose, reconfigurable, modular lunar surface vehicle. And, with the right attachments and/or crew accommodations, Chariot will be capable of serving a large number of functions. C1 [Harrison, Dan A.; Ambrose, Robert; Bluethmann, Bill; Junkin, Lucien] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Harrison, DA (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Pkwy, Houston, TX 77058 USA. EM Daniel.a.harrison@nasa.gov NR 2 TC 11 Z9 11 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1 EP 14 DI 10.1109/AERO.2008.4526234 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200001 ER PT S AU Nesnas, IAD Abad-Manterola, P Edlund, JA Burdick, JW AF Nesnas, Issa A. D. Abad-Manterola, Pablo Edlund, Jeffrey A. Burdick, Joel W. GP IEEE TI Axel mobility platform for steep terrain excursions and sampling on planetary surfaces SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The recent discovery of bright new deposits in two crater gullies on Mars suggests that water still flows in brief spurts on Mars. In this paper, we will present the Axel rover (Figure 1) that was developed to access and sample such deposits on the inside of steep crater walls. Axel is a tethered rover that can be a payload on a lander or a larger rover. The primary features of Axel are its minimal complexity and robustness to the treacherous terrain of sites that are of scientific interest. Using a symmetrical design with three actuators, Axel is capable of operating upside down and right side up, enabling it to descend over crater promontories. With its actuated trailing link, Axel can operate on both flat and sloped terrains. Using a sampling device mounted on the trailing link, Axel can collect and store terrain samples and return to its host platform for detailed scientific sample analysis. We will present our preliminary results that demonstrated Axel's ability to traverse both flat and sloped rocky terrain including 90 degrees vertical cliffs and collecting soil samples on slopes ranging from 10 degrees - 40 degrees in the JPL Mars Yard. C1 [Nesnas, Issa A. D.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Abad-Manterola, Pablo; Edlund, Jeffrey A.; Burdick, Joel W.] CALTECH, Pasadena, CA 91125 USA. RP Nesnas, IAD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM nesnas@jpl.nasa.gov; pablo@caltech.edu; jedlund@caltech.edu; jwb@robotics.caltech.edu FU California Institute of Technology FX This work is a joint collaboration between Caltech and the Jet Propulsion Laboratory. The work was done at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 15 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200002 ER PT S AU Thueer, T Siegwart, R Backes, PG AF Thueer, Thomas Siegwart, Roland Backes, Paul G. GP IEEE TI Planetary vehicle suspension options SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB A study of locomotion performance of different suspension types was conducted in order to find the rover that matches best any given mission requirements. Two modeling approaches were chosen to evaluate the performance on hard ground and obstacles, as well as on loose soil and inclined planes. A number of metrics were defined which precisely specify what qualifies as good or bad performance. The simulations revealed significant differences between the various configurations for important metrics like torque, power or velocity. These results were used to characterize the performance of each rover and put it in relation to the weighted mission requirements. The sum of the performances multiplied by the weight factors of the requirements was taken as the measure for how good a rover fits the mission needs. This study has shown that a four wheeled rover can be a valuable alternative to the rocker bogie but only in. very specific missions. C1 [Thueer, Thomas; Siegwart, Roland] ETH, Autonomous Syst Lab, Tannenstr 3, CH-8092 Zurich, Switzerland. [Backes, Paul G.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Thueer, T (reprint author), ETH, Autonomous Syst Lab, Tannenstr 3, CH-8092 Zurich, Switzerland. EM thomas.thueer@mavt.ethz.ch; roland.siegwart@mavt.ethz.ch; Paul.G.Backes@jpl.nasa.gov RI Siegwart, Roland/A-4495-2008 OI Siegwart, Roland/0000-0002-2760-7983 NR 25 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 26 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200003 ER PT S AU Backes, P Helmick, D Bajracharya, M Khatib, O Padois, V Warren, J AF Backes, Paul Helmick, Daniel Bajracharya, Max Khatib, Oussama Padois, Vincent Warren, James GP IEEE TI Results of coring from a low mass rover SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID EXPLORATION ROVERS AB Technology for coring from a low-mass rover has been developed to enable core sample acquisition where a planetary rover experiences moderate slip during the coring operation. A new stereo vision technique, Absolute Motion Visual Odometry, is used to measure rover slip during coring and the slip is accommodated through corresponding arm pose updating. Coring rate is controlled by feedback of the measured force of the coring tool against the environment. Test results in the JPL Marsyard show that coring from a low-mass rover with slip is feasible. C1 [Backes, Paul; Helmick, Daniel; Bajracharya, Max] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. [Khatib, Oussama; Padois, Vincent; Warren, James] Stanford Univ, Stanford, CA 94305 USA. RP Backes, P (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM Paul.G.Backes@jpl.nasa.gov; khatib@cs.stanford.edu FU National Aeronautics and Space Administration (NASA); Mars Technology Program; NASA Science Mission Directorate FX The research described in this publication was carried out at the Jet Propulsion Laboratory of California Institute of Technology and Stanford University under contract from the National Aeronautics and Space Administration (NASA), with funding from the Mars Technology Program, NASA Science Mission Directorate. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 53 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200005 ER PT S AU Backes, P Zimmerman, W Jones, J Gritters, C AF Backes, Paul Zimmerman, Wayne Jones, Jack Gritters, Caleb GP IEEE TI Harpoon-based sampling for planetary applications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Harpoon-based sampling techniques for sample acquisition from planetary rovers and aerobots have been developed. The approach enables access to samples on nearby steep terrain or from unstable mobile platforms with small mass and volume impacts. For rover-based sampling, alterative harpoon concepts were compared and the crossbow approach was selected. A prototype system was fabricated, mounted on a rover, and tested in the JPL marsyard. Also, two penetrator concepts were developed and tested for aerobot deployment to icy-regolith environments. One concept is a passive drop penetrator and the other is an active pyro-activated penetrator. Results of both the design and test efforts with the harpoon-based sampling systems are presented. C1 [Backes, Paul; Zimmerman, Wayne; Jones, Jack] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. [Gritters, Caleb] George Fox Univ, Newberg, OR USA. RP Backes, P (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM Paul.G.Backes@jpl.nasa.gov; Wayne.F.Zimmerman@jpl.nasa.gov; Jack.A.Jones@jpl.nasa.gov; cgritters04@georgefox.edu FU National Aeronautics and Space Administration (NASA); Mars Technology Program; NASA Science Mission Directorate; NASA Space Science Vision Missions FX The research described in this publication was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract from the National Aeronautics and Space Administration (NASA), with funding from the Mars Technology Program, NASA Science Mission Directorate, and the NASA Space Science Vision Missions. We also appreciate contributions by Stewart Sherrit,Mircea Badescu, and Jay Wu for assistance in designs of the gravity drop harpoon. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 60 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200006 ER PT S AU Elfes, A Hall, JL Kulczycki, EA Clouse, DS Morfopoulos, AC Montgomery, JF Cameron, JM Ansar, A Machuzak, RJ AF Elfes, Alberto Hall, Jeffery L. Kulczycki, Eric A. Clouse, Daniel S. Morfopoulos, Arin C. Montgomery, James F. Cameron, Jonathan M. Ansar, Adnan Machuzak, Richard J. GP IEEE TI An autonomy architecture for aerobot exploration of the saturnian moon Titan SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Huygens probe arrived at Saturn's moon Titan on January 14, 2005, unveiling a world that is radically different from any other in the Solar system. The data obtained, complemented by continuing observations from the Cassini spacecraft, show methane lakes, river channels and drainage basins, sand dunes, cryovolcanos and sierras. This has lead to an enormous scientific interest in a follow-up mission to Titan, using a robotic lighter-than-air vehicle (or aerobot). Aerobots have modest power requirements, can fly missions with extended durations, and have very long distance traverse capabilities. They can execute regional surveys, transport and deploy scientific instruments and in-situ laboratory facilities over vast distances, and also provide surface sampling at strategic science sites. This paper describes our progress in the development of the autonomy technologies that will be required for exploration of Titan. We provide an overview of the autonomy architecture and some of its key components. We also show results obtained from autonomous flight tests conducted in the Mojave desert. C1 [Elfes, Alberto; Hall, Jeffery L.; Kulczycki, Eric A.; Clouse, Daniel S.; Morfopoulos, Arin C.; Montgomery, James F.; Cameron, Jonathan M.; Ansar, Adnan; Machuzak, Richard J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Elfes, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Elfes, Alberto/E-2463-2011 OI Elfes, Alberto/0000-0003-2433-995X NR 16 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 79 EP 87 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200008 ER PT S AU Livesey, N Santee, M Stek, P Waters, J Levelt, P Veefkind, P Kumer, J Roche, A AF Livesey, Nathaniel Santee, Michelle Stek, Paul Waters, Joe Levelt, Pieternel Veefkind, Pepijn Kumer, Jack Roche, Aidan GP IEEE TI A future "Global Atmospheric Composition Mission" (CACM) concept SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Resolution of important outstanding questions in air quality, climate change and ozone layer stability demands global observations of multiple chemical species with high horizontal and vertical resolution from the boundary layer to the stratopause. We present a mission concept that delivers the needed atmospheric composition observations, along with cloud ice and water vapor data needed for improvements in climate and weather forecasting models. The mission comprises ultraviolet and infrared nadir and microwave limb viewing instruments observing wide swaths each orbit. We review the scientific goals of the mission and the measurement capabilities this concept will deliver. We describe how precessing orbits offer significant improvements in temporal resolution and diurnal coverage compared to sun-synchronous orbits. Such improvements are needed to quantify the impact of critical "fast processes" such as deep convection on the composition and radiative properties of the upper troposphere, a region where water vapor and ozone are strong but poorly understood greenhouse gases. This concept can serve as the "Global Atmospheric Composition Mission" (GACM) recently recommended by the National Academy of Sciences decadal survey as one of 17 priority earth science missions for the coming decade. C1 [Livesey, Nathaniel; Santee, Michelle; Stek, Paul; Waters, Joe] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Levelt, Pieternel; Veefkind, Pepijn] Royal Dutch Meteorol Inst, Delft, Netherlands. [Kumer, Jack; Roche, Aidan] Lockheed Martin, Palo Alto, CA USA. RP Livesey, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hvesey@mls.jpl.nasa.gov FU National Aeronautics and Space Administration FX The research described in this (publication or paper) carried out at the Jet Propulsion Laboratory, California Institute of Technology, was under a contract with the National Aeronautics and Space Administration. NR 9 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 102 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200010 ER PT S AU Green, RO Asner, G Ungar, S Knox, R AF Green, Robert O. Asner, Greg Ungar, Stephen Knox, Robert GP IEEE TI NASA mission to measure global plant physiology and functional types SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB A NASA Earth mission concept has been developed that focuses on a set of science objectives related to the measurement of plant physiology and functional type for terrestrial and aquatic ecosystems. The NRC Decadal Survey specifically calls for the HyspIRI mission to measure terrestrial and aquatic ecosystems. A review of the literature in conjunction with analysis of ongoing ecosystem research established imaging spectroscopy in the solar reflected portion of the spectrum as the appropriate approach to address these objectives. For these topics a detailed requirement analysis was performed that specified the measurement objectives, measurement requirements, instrument requirement and other requirements. These were distilled into a single set of spectral, radiometric, spatial, uniformity and temporal requirement. Key among these are: spectral coverage from 380 to 2500 nm at 10 nm sampling, radiometric resolution and precision giving high signal-to-noise ratios for dark aquatic targets, spatial sampling of 60 in, spectral and spectral IFOV uniformity > 95%, and temporal coverage with a 19 day repeat at the equator. C1 [Green, Robert O.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Asner, Greg] Carnegie Inst Sci, Dept Global Ecol, 290 Panama St, Stanford, CA 94305 USA. [Ungar, Stephen; Knox, Robert] NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RP Green, RO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rog@jpl.nasa.gov RI Knox, Robert/E-9657-2011; Asner, Gregory/G-9268-2013 OI Asner, Gregory/0000-0001-7893-6421 NR 6 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 114 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200011 ER PT S AU Spilker, TR Reh, KR Elliott, JO Lorenz, R Spencer, J AF Spilker, Thomas R. Reh, Kim R. Elliott, John O. Lorenz, Ralph Spencer, John GP IEEE TI The "Billion Dollar Box" Study of science missions to saturnian satellites SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Cassini/Huygens (C/H) mission investigations verify Saturnian satellites Titan and Enceladus as objects of intense interest to planetary scientists and astrobiologists. Recently NASA commissioned a study of potential relatively low-cost missions to these icy satellites, led by the Jet Propulsion Laboratory (JPL) with science and engineering teams from prominent universities, FFRDCs, and NASA centers. NASA was interested in determining whether there are scientifically viable missions to Titan or Enceladus within the constraints of a (possibly slightly expanded) New Frontiers mission. The C/H mission's extremely capable instrumentation and thorough investigation of the Saturn system make that a difficult, though not obviously impossible, task. Any such mission must exceed C/H capabilities (in, for instance, imaging coverage or resolution, or range of constituents identifiable) to be scientifically worthwhile. Beginning in October 2006 these teams assessed science objectives for the two destinations and surveyed architectural options for implementing worthwhile subsets of the global lists of science objectives, attempting to find mission concepts both scientifically justifiable and within New Frontiers constraints. These studies were completed in early 2007 and the somewhat surprising results, that there appear to be no such missions, reported to NASA. This presentation gives the results of the studies and examines interesting individual missions. C1 [Spilker, Thomas R.; Reh, Kim R.; Elliott, John O.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Lorenz, Ralph] Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. [Spencer, John] Inst Sound & Vibrat Res, Boulder, CO USA. RP Spilker, TR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Thomas.R.Spilker@jpl.nasa.gov RI Lorenz, Ralph/B-8759-2016 OI Lorenz, Ralph/0000-0001-8528-4644 NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 136 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200013 ER PT S AU Devirian, M AF Devirian, Michael GP IEEE TI Exploring ExoPlanets: NASA's future space missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB 'There are infinite worlds both like and unlike this world of ours... We must believe that in all worlds there are living creatures and plants and other things we see in this world." Epicurus (c. 300 BCE) "Do there exist many worlds, or is there but a single world? This is one of the most noble and Exalted questions in the study of Nature." Albertus Magnus, d. 1280 NASA planning for the discovery and exploration of "exoplanets", that is, planets around stars other than our own, has been underway for more than a decade. During that time, over 250 exoplanets have been discovered using ground-based techniques. Existing space assets such as the Hubble Space Telescope and Spitzer Space Telescope have been able to provide follow-up observations to characterize the planets and the systems they occupy. Inherent limitations of the available techniques and instuments have limited these discoveries to large planets in odd orbits. Still, these activities add significantly to our understanding of the nature of the investigations that win be required to characterize terrestrial, potentially habitable, exoplanets. We discuss the technology investments and accomplishments that have resulted from the early investments in NASA's exoplanet exploration program. A rich set of investigation types that now are at hand to probe exoplanet science is discussed. A new strategic pathway is discussed that, while constrained by budgetary realities in the federal process, promises progress with new smaller space missions to move this emergent field forward, and leading eventually to the flagship missions that will bring us the images and understanding of that "pale blue dot". C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devirian, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 145 EP 152 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200014 ER PT S AU Donnellan, A Rosen, P Graf, J Loverro, A Freeman, A Treuhaft, R Oberto, R Simard, M Rignot, E Kwok, R Pi, XP Blair, JB Abdalati, W Ranson, J Zebker, H Hager, B Shugart, H Fahnestock, M Dubayah, R AF Donnellan, Andrea Rosen, Paul Graf, Jim Loverro, Adam Freeman, Anthony Treuhaft, Robert Oberto, Robert Simard, Marc Rignot, Eric Kwok, Ronald Pi, Xiaoqing Blair, J. Bryan Abdalati, Waleed Ranson, Jon Zebker, Howard Hager, Bradford Shugart, Hank Fahnestock, Mark Dubayah, Ralph GP IEEE TI Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI) SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID FOREST BIOMASS; RADAR; HEIGHT; TOPOGRAPHY; LIDAR AB The National Research Council Earth Science Decadal Survey, Earth Science Applications from Space, recommends that DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice), an integrated L-band InSAR and multibeam Lidar mission, launch in the 2010-2013 timeframe. The mission will measure surface deformation for solid Earth and cryosphere objectives and vegetation structure for understanding the carbon cycle. InSAR has been used to study surface deformation of the solid Earth and cryosphere and more recently vegetation structure for estimates of biomass and ecosystem function. Lidar directly measures topography and vegetation structure and is used to estimate biomass and detect changes in surface elevation. The goal of DESDynI is to take advantage of the spatial continuity of InSAR and precision and directness of Lidar. There are several issues related to the design of the DESDynI mission, including combining the two instruments into a single platform, optimizing the coverage and orbit for the two techniques, and carrying out the science modeling to define and maximize the scientific output of the mission. C1 [Donnellan, Andrea; Rosen, Paul; Graf, Jim; Loverro, Adam; Freeman, Anthony; Treuhaft, Robert; Oberto, Robert; Simard, Marc; Rignot, Eric; Kwok, Ronald; Pi, Xiaoqing; Blair, J. Bryan; Abdalati, Waleed; Ranson, Jon; Zebker, Howard; Hager, Bradford; Shugart, Hank; Fahnestock, Mark; Dubayah, Ralph] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Donnellan, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrea.Donnellan@jpl.nasa.gov RI Mitchard, Edward/C-6346-2009; Khachadourian, Diana/C-8513-2012; Blair, James/D-3881-2013; Rignot, Eric/A-4560-2014 OI Rignot, Eric/0000-0002-3366-0481 FU Jet Propulsion Laboratory, California Institute of Technology; National Aeronautics and Space Administration FX We'd like to thank the numerous other scientists and engineers contributing to DESDynI within the NASA centers and at the universities, but especially Bryan Blair, Waleed Abdalati and Jon Ranson of GSFC, Howard Zebker of Stanford University, Brad Hager of MIT, Hank Shugart of U. of Virginia, Mark Fahnestock of UNH and Ralph Dubayah of U. of MD. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. NR 20 TC 2 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 163 EP + PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200016 ER PT S AU Deutsch, M Abilleira, F Bell, D Chodas, J Edwards, C Harmon, C Kerridge, S Kinsey, R Komarek, T Lisman, D Lopez, S Vozoff, J Willacy, K Winterhalter, D AF Deutsch, Marie Abilleira, Fernando Bell, David Chodas, Jan Edwards, Chad Harmon, Corey Kerridge, Stuart Kinsey, Robert Komarek, Tom Lisman, Doug Lopez, Saturnino Vozoff, Joanne Willacy, Karen Winterhalter, Daniel GP IEEE TI The Mars science orbiter concept SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Launch opportunities to explore Mars repeat every 26 months. In the 2013 opportunity, NASA studied launching a high performance science orbiter with extended telecom capabilities. This Mars Science Orbiter (MSO) would perform its science investigations and telecom infrastructure tasks over a period of 10 years in two consecutive orbits around Mars: one with science emphasis, the other emphasizing telecommunications services. While the individual science investigations of MSO would be decided competitively by an Announcement of Opportunity, the NASA science community has identified Atmospheric Science as the primary science thrust for the mission objectives. A high-resolution camera supporting the Mars infrastructure for landing site selection would complement the atmospheric science goals. The Atmospheric Science plan for MSO is centered on the two major science goals of atmospheric signatures and atmospheric state. Global maps of atmospheric constituents over time would provide the data necessary to characterize trace gas profiles, their sources and the dynamics of their transport to detect possible signatures of habitable zones and life. In addition, climatological monitoring and observing atmospheric processes would build on current climate/weather data sets, as well as contribute new data for transport and atmospheric dynamics models. The JPL MSO study team has been focusing on designing a concept for the science mission outlined above. However, other concepts for MSO are under investigation at this time as well. This paper describes a possible mission concept for the 2013 Mars launch opportunity. The actual NASA Mars Program plans and implementation may differ(12). C1 [Deutsch, Marie; Abilleira, Fernando; Bell, David; Chodas, Jan; Edwards, Chad; Harmon, Corey; Kerridge, Stuart; Komarek, Tom; Lisman, Doug; Lopez, Saturnino; Vozoff, Joanne; Willacy, Karen; Winterhalter, Daniel] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deutsch, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 176 EP 186 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200017 ER PT S AU Chen, F Kazarians, G Beaudet, R Kern, R AF Chen, Fei Kazarians, Gayane Beaudet, Robert Kern, Roger GP IEEE TI An evaluation of novel cleaning techniques for planetary protection applications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA has an aggressive plan for exploring Mars. Future in situ life detection and sample return missions will rely on clean and effectively sterile spacecraft to ensure reliable, valid science measurements. These spacecraft levy substantial requirements for planetary protection. Here, we report the results of a comparative analysis of the efficacy of three different cleaning approaches to remove bacterial spores from a series of surrogate spacecraft materials, parts, as well as cleaning challenging structures. The purpose of this study is to identify cleaning methods that achieve a minimum of a 4-log reduction of bioburden from inoculated surfaces. We believe that surfaces efficiently cleaned do not transfer biological particles, particularly spores, which when placed in close proximity with other materials become "effectively sterile." Our results indicate that a novel cleaning method, which utilize vacuum cycle nucleation (VCN) enabled technologies, can effectively remove bacterial spores from surrogate spacecraft material coupons, piece parts and structures. This cleaning technology may be a potential candidate for sterilizing Mars Lander systems, reducing the cost, risk, and material constraints encumbered by use of dry heat sterilization and common cleaning practices(1,2). C1 [Chen, Fei; Kazarians, Gayane; Beaudet, Robert; Kern, Roger] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chen, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 187 EP 194 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200018 ER PT S AU Conley, CA Billings, L AF Conley, Catharine A. Billings, Linda GP IEEE TI Don't leave home without it:Planetary protection for robotic and human missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In planetary exploration and the search for life beyond Earth, the unique capabilities provided by human explorers will be advantageous to science only if the biological contamination associated with human presence is understood and controlled. The practice of preventing cross-contamination between the Earth and other planetary bodies is called planetary protection. NASA has a planetary protection policy in place for solar system exploration missions, and compliance with it is mandatory. Thus, planetary protection must be incorporated in mission planning and development from the beginning. NASA's planetary protection policy is intended to prevent "forward contamination", contamination of other solar system bodies by Earth microbes and organic materials, and "backward contamination", contamination of Earth by potential alien life. As NASA's space exploration program expands to encompass human as well as robotic planetary missions, planetary protection will become a more complicated enterprise(12). C1 [Conley, Catharine A.] NASA Headquarters, Sci Mission Directorate, Washington, DC 20546 USA. [Billings, Linda] NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RP Conley, CA (reprint author), NASA Headquarters, Sci Mission Directorate, Washington, DC 20546 USA. EM cassie.conley@nasa.gov NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 195 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200019 ER PT S AU Balint, TS Cutts, JA Kolawa, EA AF Balint, Tibor S. Cutts, James A. Kolawa, Elizabeth A. GP IEEE TI Technology challenges for planetary probes to dense atmospheres SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Both the 2003 Solar System Exploration Decadal Survey, by the National Research Council, and NASA's 2006 Solar System Exploration Roadmap identified Saturn, Jupiter, and Venus, as high priority scientific targets and recommended missions to explore them. Specifically, potential probe missions to these two gas giants and a proposed Venus In-Situ Explorer (VISE) mission were listed under the New Frontiers mission class. Deep probe missions to these destinations have much in common. In particular, key technologies must address: environmental protection to provide isolation from the extreme environments; environmental tolerance for exposed components or systems; and operations in these harsh environments. While these proposed missions could be designed with current technologies, advanced technologies could significantly enhance their performance and consequently the science return. Therefore, in this paper we will discuss state-of-practice technologies to mitigate conditions faced by the probes, followed by an assessment of possible mission impacts and benefits resulting from targeted technology developments. It is expected that the findings of this assessment should help NASA plan its technology investments. C1 [Balint, Tibor S.; Cutts, James A.; Kolawa, Elizabeth A.] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Balint, TS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-170U, Pasadena, CA 91125 USA. NR 7 TC 0 Z9 0 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 227 EP 233 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200023 ER PT S AU Kelliher, WC Carlberg, IA Elam, WT Willard-Schmoe, E AF Kelliher, Warren C. Carlberg, Ingrid A. Elam, W. T. Willard-Schmoe, Ella GP IEEE TI Performance of a Borehole X-ray Fluorescence Spectrometer for planetary exploration SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB We have designed and constructed a Borehole X-ray Fluorescence Spectrometer (XRFS) as part of the Mars Subsurface Access program [1]. It can be used to determine the composition of the Mars regolith at various depths by insertion into a pre-drilled borehole. The primary requirements and performance metrics for the instrument are to obtain parts-per-million (ppm) lower limits of detection over a wide range of elements in the periodic table (Magnesium to Lead). Power consumption during data collection was also measured. The prototype instrument is complete and preliminary testing has been performed. Terrestrial soil Standard Reference Materials were used as the test samples. Detection limits were about 10 weight ppm for most elements, with light elements being higher, up to 1.4 weight percent for magnesium. Power consumption (excluding ground support components) was 12 wafts(12). C1 [Kelliher, Warren C.; Carlberg, Ingrid A.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. [Elam, W. T.; Willard-Schmoe, Ella] Univ Washington, Appl Phys Lab, Seattle, WA 98195 USA. RP Kelliher, WC (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM Warren.C.Kelliher@nasa.gov; ingrid.a.carlberg@nasa.gov; wtelam@apl.washington.edu; ella@apl.washington.edu FU NASA Headquarters as part of the Mars Technology Program, Subsurface Access administered by the Jet Propulsion Laboratory; University of Washington under NASA [NNL05AA49C] FX This project was funded by NASA Headquarters as part of the Mars Technology Program, Subsurface Access administered by the Jet Propulsion Laboratory. We are indebted to the program managers, Suparna Mukherjee and Chester Chu. The device design and construction were performed by the Ocean Engineering Department of the Applied Physics Laboratory: Russ Light, Vern Miller, Pete Sabin, Fran Olson, Tim Wen, and Dan Stearns. The performance reported here is due to their efforts. The University of Washington effort was funded under NASA contract NNL05AA49C. NR 2 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 234 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200024 ER PT S AU Lange, RD AF Lange, Robert D. GP IEEE TI Cassini-Huygens mission overview and recent science results SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SATURNIAN SYSTEM; ENCELADUS AB The Cassini-Huygens Project is an international science mission to the Saturnian system. Three space agencies and 17 nations contributed to building the Cassini spacecraft and Huygens probe. The Cassini orbiter is managed and operated by NASA's Jet Propulsion Laboratory. The Huygens probe was built and operated by the European Space Agency. The prime mission design for Cassini-Huygens calls for a four-year orbital survey of Saturn, its rings, magnetosphere, and satellites, and the descent into Titan's atmosphere by the Huygens probe. The Cassini orbiter tour consists of 76 orbits around Saturn with 45 close Titan flybys and 8 targeted icy satellite flybys. The Cassini orbiter spacecraft carries twelve scientific instruments that perform a wide range of observations on a multitude of designated targets. The Huygens probe carried six additional instruments that provided in situ and remote sensing of the atmosphere and surface of Titan. Now over three- years into the prime mission, the Cassini orbiter continues to study the Saturnian system, returning a wealth of knowledge for present and future generations of scientists. This paper provides an overview of the CassiniHuygens mission and highlights selected science results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lange, RD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 0 Z9 0 U1 2 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 247 EP 256 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200026 ER PT S AU Vane, D Stephens, GL AF Vane, Deborah Stephens, Graeme L. GP IEEE TI The CloudSat Mission and the A-Train: A Revolutionary Approach to Observing Earth's Atmosphere SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID VISIBLE OPTICAL DEPTH; RADAR AB On April 28, 2006 a millimeter radar system, designed expressly for the vertical profiling of hydrometeors, was launched from Vandenburg Air Force Base. Both Cloudsat, carrying the Cloud Profiling Radar (CPR), and the lidar satellite CALIPSO, were inserted into nearly identical orbits each approximately one minute behind the NASA Earth Observing System (EOS) Aqua satellite and in formation with the French PARASOL satellite and the EOS Aura satellite. This creates the ATrain satellite constellation. `Ihe early results of the CloudSat mission underscore the value of synergy of the ATrain observations for studying clouds and precipitation. C1 [Vane, Deborah] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Stephens, Graeme L.] Colorado State Univ, Fort Collins, Ft Collins, CO 80523 USA. RP Vane, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM dvane@jpl.nasa.gov; stephens@atmos.colostate.edu NR 6 TC 0 Z9 0 U1 5 U2 5 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 257 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200027 ER PT S AU Goldstein, B Shotwell, R AF Goldstein, Barry Shotwell, Robert GP IEEE TI Phoenix - The first Mars Scout mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID HYDROGEN; ODYSSEY AB As-12 the first of the new Mars Scouts missions, the Phoenix project was selected by NASA in August of 2003. Four years later, almost to the day, Phoenix was launched from Cape Canaveral Air Station and successfully injected into an interplanetary trajectory on its way to Mars. This paper will highlight some of the key changes since the 2006 IEEE paper of the same name, as well as activities, challenges and problems encountered on the way to the launch pad. Phoenix "Follows the water" responding directly to the recently published data from Dr. William Boynton, PI (and Phoenix co-I) of the Mars Odyssey Gamma Ray Spectrometer (GRS). GRS data indicate extremely large quantities of water ice (up to 50% by mass) within the upper 50 cm of the northern polar regolith. Phoenix will land within the north polar region at 68.2 degrees N, 233.4 degrees W identified by GRS to harbor near surface water ice and provide in-situ confirmation of this extraordinary find. Our mission will investigate water in all its phases, and will investigate the history of water as evidenced in the soil characteristics that will be carefully examined by the powerful suite of onboard instrumentation. Access to the critical subsurface region expected to contain this information is made possible by a third generation robotic arm capable of excavating die expected Martian regolith to a depth of 1 m. Phoenix has four primary science objectives: 1) Determine the polar climate and weather, interaction with the surface, and composition of the lower atmosphere around 70 degrees N for at least 90 sols focusing on water, ice, dust, noble gases, and CO2. Determine the atmospheric characteristics during descent through the atmosphere. 2) Characterize the geomorphology and active processes shaping the northern plains and the physical properties of the near surface regolith focusing on the role of water. 3) Determine the aqueous mineralogy and chemistry as well as the adsorbed gases and organic content of the regolith. Verify the Odyssey discovery of near-surface ice. 4) Characterize the history of water, ice, and the polar climate. Determine the past and present biological potential of the surface and subsurface environments. C1 [Goldstein, Barry; Shotwell, Robert] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Goldstein, B (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 5 TC 1 Z9 1 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 262 EP 278 PG 17 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200028 ER PT S AU Brophy, JR Rayman, MD Pavri, B AF Brophy, John R. Rayman, Marc D. Pavri, Betina GP IEEE TI Dawn: An ion-propelled journey to the beginning of the solar system SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID MISSION; CERES; VESTA AB The Dawn mission is designed to perform a scientific investigation of the two most massive main-belt asteroids Vesta and Ceres. These bodies are believed to preserve records of the physical and chemical conditions present during the formation of the solar system. The mission uses an ion propulsion system to enable the single Dawn spacecraft and its complement of scientific instruments to orbit both of these asteroids. Dawn's three science instruments - the gamma ray and neutron detector, the visible and infrared mapping spectrometer, and the primary framing camera - were successfully tested after launch and are functioning normally. The ion propulsion system includes three ion thrusters of the type flown previously on the National Aeronautics and Space Administration's (NASA's) Deep Space 1 mission. A minimum of two ion thrusters is necessary to accomplish the Dawn mission. Checkout of two of the ion thrusters was completed as planned within 30 days after launch. This activity confirmed that the spacecraft has two healthy ion thrusters. While further checkout activities are still in progress, the activities completed as of the end of October indicate that the spacecraft is well on its way toward being ready for the start of the thrusting-cruise phase of the mission beginning December 17, 2007*(dagger). C1 [Brophy, John R.; Rayman, Marc D.; Pavri, Betina] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brophy, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 299 EP 307 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200031 ER PT S AU Alexander, C Holmes, D Goldstein, R Parker, J AF Alexander, C. Holmes, D. Goldstein, R. Parker, J. GP IEEE TI The US Rosetta Project: Mars Gravity Assist SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Since launch on March 2, 2004, the International Rosetta Mission has flown by the Earth/Moon system one time and conducted several distant observations of comets, including support for the Deep Impact measurements of comet 9 P/Tempel 1. In 2007, Rosetta flew by Mars for a gravity assist, and conducted observations of the Martian upper atmosphere as well as extended observations, in support of the New Horizons Jupiter encounter, of the Jovian magnetotail and lo torus. In late 2007 Rosetta had its second encounter with the Earth/Moon system. NASA's contribution to the Rosetta mission consists of three hardware experiments, and the portion of the electronics package for a fourth, as well as the participation of an Interdisciplinary Scientist (IDS); backup tracking, telecommunications, and navigation assurance provided by the Deep Space Network (DSN); support for the scientific participation of U.S. investigators on non-U.S. PI-led experiments. Collectively these elements are known as the U.S. Rosetta Project. In this paper we will update the status of the instruments following the both the Mars and Earth/Moon gravity assists. In addition, we will present a s immar of the science observations for both Mars and Jupiter(12). C1 [Alexander, C.; Holmes, D.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Goldstein, R.; Parker, J.] Southwest Res Inst, San Antonio, TX USA. RP Alexander, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Claudia.J.Alexander@jpl.nasa.gov; Dwight.P.Holmes@jpl.nasa.gov; rgoldstein@swri.edu; joel@boulder.swri.edu NR 9 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 308 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200032 ER PT S AU Livermore, TR Crisp, D AF Livermore, Thomas R. Crisp, David GP IEEE TI The NASA Orbiting Carbon Observatory mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID CO2 AB The Orbiting Carbon Observatory (OCO) is a NASA Earth System Science Pathfinder (ESSP) mission that is currently under development at the Jet Propulsion Laboratory (JPL). OCO will make global, space-based measurements of atmospheric carbon dioxide (CO2) with the precision, resolution, and coverage needed to characterize regional-scale sources and sinks of this important greenhouse gas. The observatory consists of a dedicated spacecraft bus that carries a single instrument. The bus employs single-string version of Orbital Sciences Corporation (OSC) LEOStar-2 architecture. This 3-axis stabilized bus includes a propulsion system for orbit insertion and maintenance, provides power, points the instrument, receives and processes commands from the ground, and records, stores, and downlinks science and engineering data. The OCO instrument incorporates 3 coboresighted, high resolution grating spectrometers that will make coincident measurements of reflected sunlight in nearinfrared CO2 and molecular oxygen (O-2) bands. The instrument was designed and manufactured by Hamilton Sundstrand (Pomona, CA), and then integrated, flight qualified, and calibrated by JPL. It is scheduled for delivery to OSC (Dulles, VA) for integration with the spacecraft bus in the spring of 2008. OCO will be launched from the Vandenberg Air Force Base on a dedicated OSC Taurus XL launch vehicle in December 2008. It will fly in formation with the Earth Observing System Afternoon Constellation, a group of satellites that files in a 98.8 minute, 705 kin altitude, sun-synchronous orbit. This orbit provides coverage of the sunlit hemisphere with a 16-day ground track repeat cycle. OCO will fly similar to 4 minutes ahead of the EOS Aqua platform, with an ascending nodal crossing time of similar to 1:26 PM. The OCO science data will be transmitted to the NASA Ground Network Stations in Alaska and Virginia, and then transferred to the OCO Ground Data System at JPL. There, the CO2 and O-2 spectra will be analyzed by the OCO Science Team to provide spatially resolved estimates of the column-averaged CO2 dry air mole fraction, X-CO2. These measurements are expected to improve our understanding of the nature and processes that regulate atmospheric CO2 enabling more reliable forecasts of CO2 buildup and its impact on climate change(12). C1 [Livermore, Thomas R.; Crisp, David] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Livermore, TR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 317 EP 322 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200033 ER PT S AU Tripathi, RK Nealy, JE AF Tripathi, Ram K. Nealy, John E. GP IEEE TI Lunar radiation risk assessment and shielding design for ionizing space radiation SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA is now focused on the agency's vision for space exploration encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. As a result, there is a focus on long duration space missions. NASA is committed to the safety of the missions and the crew, and there is an overwhelming emphasis on the reliability issues for space missions and the habitat. The cost effective design of the spacecraft demands a very stringent requirement on the optimization process. Exposure from the hazards of severe space radiation in deep space and/or long duration missions is a critical design constraint and a potential 'show stopper.' Thus, protection from the hazards of severe space radiation is of paramount importance to the agency's vision. It is envisioned to have long duration human presence on the Moon for deep space exploration. Tlie exposures from ionizing radiation - galactic cosmic radiation and solar particle events - and optimized shield design for a short-term and a long-term mission to Moon have been investigated. It is found that the technology of today is adequate for short-term safe human missions to Moon, and revolutionary technologies need to be developed for long duration Moon missions and/or deep space missions. The study will provide a guideline for radiation exposure and protection for long duration missions and career astronauts and their safety(12). C1 [Tripathi, Ram K.; Nealy, John E.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Tripathi, RK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM ram.k.tripathi@nasa.gov; john.e.nealy@nasa.gov NR 15 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 323 EP 333 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200034 ER PT S AU Pierce, ME Fox, GC Aydin, G Qi, ZG Donnellan, A Parker, JW Granat, R AF Pierce, Marlon E. Fox, Geoffrey C. Aydin, Galip Qi, Zhigang Donnellan, Andrea Parker, Jay W. Granat, Robert GP IEEE TI QuakeSim: Web Services, Portals, and Infrastructure for Geophysics SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB ,We discuss significant recent updates and revisions to the QuakeSim portal and Web services, which provide access to geophysical applications, data sets, and real time sensor data. These new developments include a) significant updates to the Web portal, b) a revision of Web Services to better encapsulate applications, c) additional services for generating Keyhole Markup Language markups of maps, and d) support for real-time Global Positioning Data. C1 [Pierce, Marlon E.; Fox, Geoffrey C.; Aydin, Galip; Qi, Zhigang] Indiana Univ, Community Grids Lab, 501 N Morton St, Bloomington, IN 47404 USA. [Donnellan, Andrea; Parker, Jay W.; Granat, Robert] NASA, Jet Propulsion Lab, Pasadena, CA USA. RP Pierce, ME (reprint author), Indiana Univ, Community Grids Lab, 501 N Morton St, Bloomington, IN 47404 USA. EM mpierce@cs.indiana.edu FU NASA Earth Science Technology Office FX We acknowledge the collaborations of the QuakeSim team: John Rundle (UC-Davis), Lisa Grant (UC-Irvine), and Dennis McLeod (USC). We also thank the members of the NASA REASoN project for assistance and collaboration using their GPS services. The QuakeSim project is supported by the NASA Earth Science Technology Office. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 425 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200044 ER PT S AU Guillaume, A Lee, S Braverman, A Terrile, R AF Guillaume, Alexandre Lee, Seungwon Braverman, Amy Terrile, Richard GP IEEE TI Entropy constrained clustering algorithm guided by differential evolution SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID VECTOR QUANTIZATION AB Entropy constrained vector quantization (ECVQ) is a clustering technique [1] that has been successfully used to describe effliciently large amounts of data collected by the NASA Earth Observing System. The manipulation of this algorithm requires the user to set two parameters: the entropy Lagrange multiplier, and the initial guess for the number of clusters. In this work, we describe an integrated solution that uses a differential evolution algorithm to determine these two parameters. By optimizing two objective functions, entropy and distortion, we find that the solution that best describes the data is located at the inflection point in the Pareto front, i.e. at the point where the tradeoff between the two competing objectives does not favor either one(12). C1 [Guillaume, Alexandre; Lee, Seungwon; Braverman, Amy; Terrile, Richard] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Guillaume, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 450 EP 458 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200047 ER PT S AU Lee, M Weidner, R Miller, C Bowman, K AF Lee, Meemong Weidner, Richard Miller, Charles Bowman, Kevin GP IEEE TI Sensor-web Operations Explorer (SOX) for Earth Science air quality mission concepts SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Future air quality missions will face significant measurement strategy design and implementation challenges. Characterizing the atmospheric state and its impact on air quality requires observations of trace gases (e.g., ozone [O-3], carbon monoxide [CO], nitrogen dioxide [NO2], sulfur dioxide [SO2]), aerosols (e.g., size and shape distributions, composition), clouds (e.g., type, height, sky coverage), and physical parameters (e.g., temperature, pressure, humidity) across temporal and spatial scales that range from minutes to days and from meters to > 10,000 km. Validating satellite measurements is another major challenge, and it requires well organized and orchestrated sub-orbital sensor web deployments. No single sensor, instrument, platform, or network can provide all of the information necessary to address this issue. Constellations of spacecraft, integrated air-borne campaigns, and distributed sensor networks have been actively pursued to achieve the needed multi-dimensional observation coverage. However, these complicated sensor webs must address how to formulate the complex design trade space, how to explore the trade space rapidly, how to establish evaluation metrics, and how to coordinate observations optimally. The Sensor-web Operations Explorer (SOX) research task under the NASA Earth Science Technology Office addresses these challenges by creating a virtual sensor-web experiment framework that can support orbital and sub-orbital observation system simulation experiment. C1 [Lee, Meemong; Weidner, Richard; Miller, Charles; Bowman, Kevin] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 470 EP 478 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200049 ER PT S AU Prakash, R Burkhart, PD Chen, A Comeaux, KA Guernsey, CS Kipp, DM Lorenzoni, LV Mendeck, GF Powell, RW Rivellini, TP Martin, AMS Sell, SW Steltzner, AD Way, DW AF Prakash, Ravi Burkhart, P. Dan Chen, Allen Comeaux, Keith A. Guernsey, Carl S. Kipp, Devin M. Lorenzoni, Leila V. Mendeck, Gavin F. Powell, Richard W. Rivellini, Tommaso P. Martin, A. Miguel San Sell, Steven W. Steltzner, Adam D. Way, David W. GP IEEE TI Mars Science Laboratory Entry, Descent, and Landing System Overview SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In 2010, the Mars Science Laboratory (MSL) mission will pioneer the next generation of robotic Entry, Descent, and Landing (EDL) systems by delivering the largest and most capable rover to date to the surface of Mars. In addition to landing more mass than prior missions to Mars, MSL will offer access to regions of Mars that have been previously unreachable. The MSL EDL sequence is a result of a more stringent requirement set than any of its predecessors. Notable among these requirements is landing a 900 kg rover in a landing ellipse much smaller than that of any previous Mars lander. In meeting these requirements, MSL is extending the limits of the EDL technologies qualified by the Mars Viking, Mars Pathfinder, and Mars Exploration Rover missions. Thus, there are many design challenges that must be solved for the mission to be successful. Several pieces of the EDL design are technological firsts, such as guided entry and precision landing on another planet, as well as the entire Sky Crane maneuver. This paper discusses the MSL EDL architecture and discusses some of the challenges faced in delivering an unprecedented rover payload to the surface of Mars(1,2). C1 [Prakash, Ravi; Burkhart, P. Dan; Chen, Allen; Comeaux, Keith A.; Guernsey, Carl S.; Kipp, Devin M.; Lorenzoni, Leila V.; Rivellini, Tommaso P.; Martin, A. Miguel San; Sell, Steven W.; Steltzner, Adam D.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Mendeck, Gavin F.; Powell, Richard W.; Way, David W.] NASA, Johnson Space Flight Ctr, Houston, TX USA. RP Prakash, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ravi.Prakash@jpl.nasa.gov NR 8 TC 1 Z9 1 U1 1 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 479 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200050 ER PT S AU Sengupta, A Steltzner, A Comeaux, K Candler, G Barnhardt, M Pantano, C Bell, J Heineck, JT Schairer, E AF Sengupta, Anita Steltzner, Adam Comeaux, Keith Candler, Graham Barnhardt, Michael Pantano, Carlos Bell, James Heineck, J. T. Schairer, Edward GP IEEE TI Results from the Mars Science Laboratory Parachute Decelerator System Supersonic Qualification Program SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In 2010 the Mars Science Laboratory (MSL) Mission will deliver the most massive and scientifically capable rover to the surface of Mars. To deliver this payload, an aerodynamic decelerator is required to decelerate the entry vehicle from supersonic to subsonic speeds, in advance of propulsive descent and touchdown on Mars. The aerodynamic deceleration will be accomplished by a mortar-deployed 21.5-m Viking-type disk-gap-band parachute (DGB), and will be the largest extra-terrestrial decelerator in the history of space exploration [1]. The parachute will deploy at up to Mach 2.2 and 750 Pa, resulting in the highest load and speed experienced by a parachute on Mars. The MSL parachute extends the envelope of the existing heritage deployment space in terms of load, size and Mach number. This has created the challenge of leveraging the existing heritage supersonic-high-altitude database, implementing a ground-based qualification program, and quantifying known aerodynamic instabilities associated with supersonic operation in the Mach regime of the MSL deployment. To address these challenges MSL has embarked upon a physics-based modeling and validation program to explore the fundamental physics associated with DGB-parachute operation in supersonic flow. The functional dependence of parachute performance and stability on Mach number, Reynolds number, parachute size, entry-vehicle size and parachute to entry vehicle proximity, is under investigation. The quantitative understanding garnered from this analytical effort will be used to leverage the existing heritage database of the Viking Lander, Viking Balloon Launched Decelerator Test (BLDT), Mars Pathfinder (MPF) and Mars Exploration Rover (MER) programs for the larger scale, deployment conditions, and modem construction techniques of the MSL parachute system. The physics-based modeling and validation effort includes the development of a coupled fluid and structural solver, i.e. fluid-structure-interaction code, and supersonic wind-tunnel experiments with subscale representations of the flight configuration. C1 [Sengupta, Anita; Steltzner, Adam; Comeaux, Keith] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Candler, Graham; Barnhardt, Michael] Univ Minnesota, Minneapolis, MN 55455 USA. [Pantano, Carlos] Univ Illinois, Urbana 61801, IL 61801 USA. [Bell, James; Heineck, J. T.; Schairer, Edward] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sengupta, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Anita.sengupta@jpl.nasa.gov; candler@aem.umn.edu; cpantano@uiuc.edu; James.H.Bell@nasa.gov NR 35 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 497 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200051 ER PT S AU Gazarik, MJ Wright, MJ Little, A Cheatwood, FM Herath, JA Munk, MM Novak, FJ Martinez, ER AF Gazarik, Michael J. Wright, Michael J. Little, Alan Cheatwood, F. McNeil Herath, Jeff A. Munk, Michelle M. Novak, Frank J. Martinez, Edward R. GP IEEE TI Overview of the MEDLI Project SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID TEMPERATURE DATA; SYSTEM AB The Mars Science Laboratory Entry, Descent, and Landing Instrumentation (MEDLI) Project's objectives are to measure aerothermal environments, sub-surface heatshield material response, vehicle orientation, and atmospheric density for the atmospheric entry and descent phases of the Mars Science Laboratory (MSL) entry vehicle. The flight science objectives of MEDLI directly address the largest uncertainties in the ability to design and validate a robust Mars entry system, including aerothermal, aerodynamic and atmosphere models, and thermal protection system (TPS) design. The instrumentation suite will be installed in the heatshield of the MSL entry vehicle. The acquired data will support future Mars entry and aerocapture missions by providing measured atmospheric data to validate Mars atmosphere models and clarify the design margins for future Mars missions. MEDLI thermocouple and recession sensor data will significantly improve the understanding of aeroheating and TPS performance uncertainties for future missions. MEDLI pressure data will permit more accurate trajectory reconstruction, as well as separation of aerodynamic and atmospheric uncertainties in the hypersonic and supersonic regimes. This paper provides an overview of the project including the instrumentation design, system architecture, and expected measurement response. C1 [Gazarik, Michael J.; Wright, Michael J.; Little, Alan; Novak, Frank J.] NASA, Langley Res Ctr, RSFSB, MS 468, Hampton, VA 23681 USA. [Martinez, Edward R.] NASA, Ames Res Ctr, Moffett Field, CA USA. RP Gazarik, MJ (reprint author), NASA, Langley Res Ctr, RSFSB, MS 468, Hampton, VA 23681 USA. EM Michael.J.Gazarik@Nasa.Gov; Michael.J.Wright@Nasa.Gov; A.Little@Nasa.Gov; F.M.Cheatwood@Nasa.Gov; Jeffrey.A.Herath@Nasa.Gov; Michelle.M.Munk@Nasa.gov; Frank.J.Novak@Nasa.Gov; Edward.R.Martinez@Nasa.Gov NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 512 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200052 ER PT S AU Adams, DS AF Adams, Douglas S. GP IEEE TI Phoenix Mars Scout landing risk assessment SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Phoenix Mars Scout lander touchdown event is described along with critical variables that determine the risk to its success. Hazards due to terrain slopes and surface rocks are considered in terms of both basic touchdown survival and science team requirements. Dynamic analyses of the landing are described as well as geometric static analyses of potential rock interferences with the solar array deployments. These data are summarized and the total risk to the lander is quantified for use in landing site certification. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Adams, DS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 524 EP 530 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200053 ER PT S AU Dunn, C Prakash, R AF Dunn, Catherine Prakash, Ravi GP IEEE TI A terminal descent sensor trade study overview for the Orion Landing and recovery system SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This trade study was conducted as a part of the Orion Landing System Advanced Development Project to determine possible Terminal Descent Sensor (TDS) architectures that could be used for a rocket assisted landing system. Several technologies were considered for the Orion TDS including radar, lidar, GPS applications, mechanical sensors, and gamma ray altimetry. A preliminary down selection occurred by comparing each sensor's ability to meet the requirements. The driving requirements included the range of operation, accuracy, and sensor development to a technology readiness level of 6 (TRL-6) by the Orion PDR in June 2008. Additionally, Orion is very mass and volume constrained, so these parameters were weighted heavily. Radar, lidar, and GPS applications all had potential to meet the requirements and were carried on for further analysis. Investigation into GPS led to concerns over potential loss of signal and required ground infrastructure, so GPS was taken out of the trade space. Remaining technologies included a Pulse-Doppler Radar, FMCW Radar, and a Hybrid Lidar ranger and velocimeter (termed the Hybrid Lidar). The trade boils down to the maturity and weather robustness of the radar options versus the mass, volume, power, and heat shield blowout port size advantage of the lidar. This trade study did not result in a recommended TDS. The trade of the mass and volume impact versus the development time and cost should be made at a higher level than this particular trade study. C1 [Dunn, Catherine; Prakash, Ravi] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dunn, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-490, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 549 EP 561 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200055 ER PT S AU Korzun, AM Cruz, JR Braun, RD AF Korzun, Ashley M. Cruz, Juan R. Braun, Robert D. GP IEEE TI A Survey of Supersonic Retropropulsion Technology for Mars Entry, Descent, and Landing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID JET; STREAM AB This paper presents a literature survey on supersonic retropropulsion technology as it applies to Mars entry, descent, and landing (EDL). The relevance of this technology to the feasibility of Mars EDL is shown to increase with ballistic coefficient to the point that it is likely required for human Mars exploration. The use of retropropulsion to decelerate an entry vehicle from hypersonic or supersonic conditions to a subsonic velocity is the primary focus of this review. Discussed are systems-level studies, general flowfield characteristics, static aerodynamics, vehicle and flowfield stability considerations, and aerothermodynamics. The experimental and computational approaches used to develop retropropulsion technology are also reviewed. Finally, the applicability and limitations of the existing literature and current state-of-the-art computational tools to future missions are discussed in the context of human and robotic Mars exploration. C1 [Korzun, Ashley M.; Braun, Robert D.] Georgia Inst Technol, Space Syst Design Lab, Atlanta, GA 30332 USA. [Cruz, Juan R.] NASA, Langley Res Ctr, Hampton, VA USA. RP Korzun, AM (reprint author), Georgia Inst Technol, Space Syst Design Lab, Atlanta, GA 30332 USA. EM akorzun@gatech.edu; Juan.R.Cruz@nasa.gov; robert.braun@ae.gatech.edu NR 45 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 579 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200057 ER PT S AU Ippolito, C Joo, S Al-Ali, K Yeh, YH AF Ippolito, Corey Joo, Sungmoon Al-Ali, Khalid Yeh, Yoo Hsiu GP IEEE TI Polymorphic control reconfiguration in an autonomous UAV with UGV collaboration SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The emergence of distributed technologies as a reliable infrastructure for real-time control is enabling a new generation of distributed plug-and-play control architectures and methodologies; increasingly common are control systems that pass real-time data across traditional system boundaries to utilize distributed remote sensing, processing, and actuation. The Polymorphic Control Systems (PCS) project formalizes constructs that permits topological reconfiguration of control systems that span multiple heterogeneous systems and multiple communication mediums, towards the goal of control coordination and strategy optimization in a multi-system environment, increased resilience to failure and uncertainty, increased overall and individual performance, and better utilization of available resources. This paper presents the concepts behind PCS, and presents results from a flight test experiment involving distributed reconfiguration of an autonomous landing controller in a collaborative multivehicle environment. These flight test experiments demonstrate one of the goals of polymorphic reconfiguration: providing emergency assistance and collaborative coordination between multiple systems to achieve safely the mission critical objectives, where a system failure would have resulted in the loss of the aircraft. C1 [Ippolito, Corey] NASA, Adapt Control & Evolvable Syst Grp, Ames Res Ctr, Moffett Field, CA 94035 USA. [Joo, Sungmoon] Stanford Univ, Dept Aeronaut & Astronaut, Stanford, CA USA. [Al-Ali, Khalid; Yeh, Yoo Hsiu] Carnegie Mellon Univ West Cost Campus, Carnegie Mellon Innovations Lab, Moffett Field, CA USA. RP Ippolito, C (reprint author), NASA, Adapt Control & Evolvable Syst Grp, Ames Res Ctr, Moffett Field, CA 94035 USA. EM corey.a.ippolito@nasa.gov; joosm@stanford.edu; alali@cmu.edu; yoohsiu.yeh@west.cmu.edu FU NASA Ames Research Center FX The authors wish to thank all those who have contributed their knowledge and expertise to make this research project a reality. Thanks to Kalmanje Krishnakumar, Mark Sumich, and the adaptive controls group at NASA Ames Research Center for their continued support of this project. Special thanks to student interns Mera Home, Matt Wallach, Brad Jackson, Matt Walliser and Ace Shelander, whose hard work made these flight tests possible. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 594 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200058 ER PT S AU Toorian, A Diaz, K Lee, S AF Toorian, Armen Diaz, Ken Lee, Simon GP IEEE TI The CubeSat approach to space access SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB As advances in technology make payloads and instruments for space missions smaller, lighter, and more power efficient, a niche market is emerging from the university community to perform rapidly developed, low-cost missions on very small spacecraft - micro, nano, and picosatellites. Among this class of spacecraft, are CubeSats, with a basic form of 10x10x10cm, weighing a maximum of 1kg. In order to serve as viable alternative to larger spacecraft, small satellite platforms must provide the end user with access to space and similar functionality to mainstream missions. However, despite recent advances, small satellites have not been able to reach their full potential. Without launch vehicles dedicated to launching small satellites as primary payloads, launch opportunities only exist in the form of co-manifest or secondary payload missions, with launches often subsidized by the government. In addition, power, size, and mass constraints create additional hurdles for small satellites. To date, the primary method of increasing a small satellite's capability has been focused on miniaturization of technology. The CubeSat Program embraces this approach, but has also focused on developing an infrastructure to offset unavoidable limitations caused by the constraints of small satellite missions. The main components of this infrastructure are: an extensive developer community, standards for spacecraft and launch vehicle interfaces, and a network of ground stations. This paper will focus on the CubeSat Program, its history, and the philosophy behind the various elements that make it a practical an enabling alternative for access to space. C1 [Toorian, Armen; Diaz, Ken; Lee, Simon] NASA, Jet Prop Lab, Pasadena, CA 90292 USA. RP Toorian, A (reprint author), NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 90292 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 620 EP 633 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200060 ER PT S AU Ballard, PG AF Ballard, Perry G. GP IEEE TI Post shuttle access to the ISS for payloads SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Department of Defense (DoD) Space Test Program (STP) is the organization responsible for providing launch services for all of DoD's R&D space experiments and has used NASA!s Manned Spaceflight capabilities (the Space Shuttle) extensively in the past for its experiments. With the Shuttle expected to retire in the 2010 timeframe a concerted effort is underway to find alternate means to send experiments to the International Space Station and, if possible, return them from the ISS. With some success STP has found alternatives to the shuttle for access to the ISS, specifically using the Russian Progress vehicle. This paper will provide a survey of ISS access methods in the post-shuttle era, focusing on capabilities of interest to the experimenter as well as processes required in the areas of manifesting, integration, and safety. Specifically it will address current alternatives to the shuttle, including Soyuz, Progress, ATV, and HTV vehicles as wen as the proposed Rocketplane-Kistler and SpacEx servicing vehicles. C1 JSC WRI, DoD Space Test Program, Human Spaceflight Payloads Off, Houston, TX 77058 USA. RP Ballard, PG (reprint author), JSC WRI, DoD Space Test Program, Human Spaceflight Payloads Off, 2101 NASA Pkwy, Houston, TX 77058 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 634 EP 639 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200061 ER PT S AU MacNeal, BE Herrell, LM AF MacNeal, Bruce E. Herrell, Linda M. GP IEEE TI Form follows function: A pragmatic approach to access-to-space for space technology experiments SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The form of access-to-space for NASA space missions is often dictated before they are designed. Typically, solicitations specify the form-i.e., the launch vehicle to be used. The investigator then tries to design a mission within the given form and cost limits. This study adopts a more pragmatic point of view: that the form of access should follow from the function of the mission. Given the function, the form of space access is then optimized. The functions of a broad range of space technology experiments and current forms of space access were analyzed. Results show that there might be a more 23 effective approach to access-to-space. The function of a mission is described by a few parameters related to the operation and success of the mission itself, and is divorced from preconceptions about access-to-space. For example, a mission may require a certain mass, power and orbit location, but not a particular launch vehicle or spacecraft bus. The study examined function parameters from hundreds of space technology experiments, including Air Force satellites, technologies reported at the NSTC 2007 conference and the 2008 Small Sat Conference, past university-class satellites and past and future missions from the NASA's New Millennium Program. Parameters from each of the experiments were catalogued and analyzed. Analysis then identified forms of access-to-space that do (or do not) support present function. Methods for accessing space represent options available to investigators in the form trade space. For form to follow function, the trade space must contain several accessible options. Our results show that form trade space may not yet be large enough for some technology experiments. The ESPA Ring, CubeSat and SIV platforms provide efficient access for many technology experiments, but a significant number of small experiments are not served. New launch options are needed. A new, fully-functional 25kg-class standard satellite bus would help to fill this gap. A support module for the ESPA Ring would also be helpful. Experiments too small for dedicated launch or standard carriers must partner in order to fly. Investigators must sort through the hundreds of potential rideshare partners and providers in government, civil and academic institutions spread throughout the world. A rideshare broker function would help to ensure that rideshare partnerships form and launch successfully. C1 [MacNeal, Bruce E.; Herrell, Linda M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP MacNeal, BE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 645 EP 658 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200063 ER PT S AU Epp, CD Robertson, EA Brady, T AF Epp, Chirold D. Robertson, Edward A. Brady, Tye GP IEEE TI Autonomous Landing and Hazard Avoidance Technology (ALHAT) SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The ALHAT Project is funded by NASA to develop an integrated AGNC (Autonomous Guidance, Navigation and Control) hardware and software system capable of detecting and avoiding surface hazards and guiding humans and cargo safely, precisely and repeatedly to designated lunar landing sites. There are important interdependencies driving the design of a lunar landing system including such things as lander hazard robustness, landing site conditions (terrain and natural lighting), trajectories, sensors, crew involvement, and others. The ALHAT System must be capable of operating in a wide range of lunar environments and supporting global lunar access for both crewed and robotic missions. This paper discusses the major factors driving the design of a lunar landing system as well as the current state of the technology development. The supporting analysis and testing results will be presented that show the system interdependencies and their relative importance, as well as the trades needed to optimize the landing system. The emphasis is on the final phase of the landing where Hazard Detection and Avoidance (HDA) and Hazard Relative Navigation (HRN) are the primary considerations in achieving a safe landing. The current sensor options being considered and the status of the development of those sensors are discussed. (c) 2008 IEEE. C1 [Epp, Chirold D.] NASA, Johnson Space Ctr EG1, Aeorsci & Flight Mech Div, Engn Directorate, 2101 NASA Pkwy, Houston, TX 77058 USA. [Robertson, Edward A.; Brady, Tye] Charles Stark Draper Lab Inc, Cambridge, MA 02139 USA. RP Epp, CD (reprint author), NASA, Johnson Space Ctr EG1, Aeorsci & Flight Mech Div, Engn Directorate, 2101 NASA Pkwy, Houston, TX 77058 USA. EM chirold.d.epp@nasa.gov; edward.a.robertson@nasa.gov; tye@draper.com NR 7 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 659 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200064 ER PT S AU Paschall, SC Brady, T Cohanim, BE Sostaric, R AF Paschall, Stephen C., II Brady, Tye Cohanim, Babak E. Sostaric, Ronald GP IEEE TI A self contained method for safe & precise lunar landing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The return of humans to the Moon will require increased capability beyond that of the previous Apollo missions. Longer stay times and a greater flexibility with regard to landing locations are among the many improvements planned. A descent and landing system that can land the vehicle more accurately than Apollo with a greater ability to detect and avoid hazards is essential to the development of a Lunar Outpost, and also for increasing the number of potentially accessible Lunar sortie locations. This descent and landing system should allow landings in more challenging terrain and provide more flexibility with regard to mission timing and lighting considerations, while maintaining safety as the top priority. The lunar landing system under development by the ALHAT (Autonomous Landing and Hazard Avoidance Technology) project is addressing this by providing terrain-relative navigation measurements to enhance global-scale precision, an onboard hazard detection system to select safe landing locations, and an Autonomous GNC (Guidance, Navigation, and Control) capability to process these measurements and safely direct the vehicle to a landing location. This landing system will enable safe and precise lunar landings without requiring lunar infrastructure in the form of navigation aids or a priori identified hazard-free landing locations. The safe landing capability provided by ALHAT uses onboard active sensing to detect hazards that are large enough to be a danger to the vehicle but too small to be detected from orbit a priori. Algorithms to interpret raw active sensor terrain data and generate hazard maps as well as identify safe sites and recalculate new trajectories to those sites are included as part of the ALHAT System. These improvements to descent and landing will help contribute to repeated safe and precise landings for a wide variety of terrain on the Moon. C1 [Paschall, Stephen C., II; Brady, Tye; Cohanim, Babak E.] Charles Stark Draper Lab Inc, 555 Technol Sq, Cambridge, MA 02139 USA. [Sostaric, Ronald] NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Paschall, SC (reprint author), Charles Stark Draper Lab Inc, 555 Technol Sq, Cambridge, MA 02139 USA. EM spaschall@draper.com; ronald.r.sostaric@nasa.gov NR 17 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 666 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200065 ER PT S AU Johnson, AE Huertas, A Werner, RA Montgomery, JF AF Johnson, Andrew E. Huertas, Andres Werner, Robert A. Montgomery, James F. GP IEEE TI Analysis of on-board hazard detection and avoidance for safe lunar landing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Landing hazard detection and avoidance technology is being pursued within NASA to improve landing safety and increase access to sites of interest on the lunar surface. The performance of a hazard detection and avoidance system depends on properties of the terrain, sensor performance, algorithm design, vehicle characteristics and the overall all guidance navigation and control architecture. This paper analyzes the size of the region that must be imaged, sensor performance parameters and the impact of trajectory angle on hazard detection performance. The analysis shows that vehicle hazard tolerance is the driving parameter for hazard detection system design. C1 [Johnson, Andrew E.; Huertas, Andres; Werner, Robert A.; Montgomery, James F.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 699 EP 707 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200068 ER PT S AU Johnson, AE Montgomery, JF AF Johnson, Andrew E. Montgomery, James F. GP IEEE TI Overview of Terrain Relative Navigation approaches for precise lunar landing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The driving precision landing requirement for the Autonomous Landing and Hazard Avoidance Technology project is to autonomously land within 100m of a predetermined location on the lunar surface. Traditional lunar landing approaches based on inertial sensing do not have the navigational precision to meet this requirement. The purpose of Terrain Relative Navigation (TRN) is to augment inertial navigation by providing position or bearing measurements relative to known surface landmarks. From these measurements, the navigational precision can be reduced to a level that meets the 100m requirement. There are three different TRN functions: global position estimation, local position estimation and velocity estimation. These functions can be achieved with active range sensing or passive imaging. This paper gives a survey of many TRN approaches and then presents some high fidelity simulation results for contour matching and area correlation approaches to TRN using active sensors. Since TRN requires an a-priori reference map, the paper concludes by describing past and future lunar imaging and digital elevation map data sets available for this purpose. C1 [Johnson, Andrew E.; Montgomery, James F.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 0 Z9 0 U1 1 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 708 EP 717 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200069 ER PT S AU Gatti, MS AF Gatti, Mark S. GP IEEE TI A phased array antenna for deep space communications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper describes a phased array antenna that has been studied for use as the next generation Deep Space Network (DSN) for NASA. The DSN currently consists of large reflector antennas located approximately equidistant around the earth and provides communications and navigation services to the NASA science missions to the solar system planets. These individual antennas range in size from 34-m to 70-m. In the future, there have been proposals to replace these antennas with a phased array, each element of which would consist of smaller reflector antennas than currently used. The total aperture could be increased as required by future missions, with total future aperture up to or more than 10 times that of the current DSN total aperture. One possible architecture for this phased array antenna is described. A breadboard phased array was constructed to demonstrate this concept. The performance of the individual antenna elements and their corresponding subsystems, and the performance of the phased array signal combiner developed for this breadboard phased array is described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gatti, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 751 EP 758 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200073 ER PT S AU Jones, DL Bagri, DS Miyatake, HC Tehrani, BJ Gatti, MS Cooper, HW AF Jones, Dayton L. Bagri, Durgadas S. Miyatake, Hiroyuki C. Tehrani, Barzia J. Gatti, Mark S. Cooper, Hamil W. GP IEEE TI Calibration of antennas during construction or expansion of radio arrays SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID FLUX AB The calibration of radio antenna performance is a well understood process, especially for single large-diameter antennas. However, the measurement of efficiency, optimal focus, pointing corrections, system temperature, and other parameters as functions of observing frequency, antenna elevation and azimuth, temperature, and wind velocity can be time-consuming. For any future arrays consisting of very large numbers of small antennas, it will be necessary to minimize the time spent calibrating each antenna. This paper considers ways to speed up the calibration of antennas being added to an existing array by taking advantage of interferometer measurements and script-based automation. C1 [Jones, Dayton L.; Bagri, Durgadas S.; Miyatake, Hiroyuki C.; Tehrani, Barzia J.; Gatti, Mark S.; Cooper, Hamil W.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 766 EP 773 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200075 ER PT S AU Vilnrotter, V Britcliffe, M Hoppe, D AF Vilnrotter, V. Britcliffe, M. Hoppe, D. GP IEEE TI Focal plane array receiver for deep-space communication SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Typical ground antennas intended for use in space communication require large apertures operating at high frequencies. The challenges involved with these applications include achieving the required antenna performance in terms of antenna aperture efficiency and pointing accuracy. The utilization of a focal plane array in place of a standard single mode feed minimizes these problems. This paper discusses the key elements required to implement a focal plane array on a large high frequency antenna. It is shown that adaptive "least mean-square" (LMS) algorithms applied to the output of the array elements obtain the optimum combining weights in real-time, even in the presence of dynamic interference such as nearby spacecraft in array's field-of-view, or planetary radiation. This adaptive optimization capability maximizes the combined output SNR in real time, ensuring maximum data throughput in the communications link when operating in the presence of receiver noise and external interference generally present during planetary encounters. C1 [Vilnrotter, V.; Britcliffe, M.; Hoppe, D.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vilnrotter, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Victor.A.Vilnrotter@jpl.nasa.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 774 EP 783 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200076 ER PT S AU Jamnejad, V Silva, A AF Jamnejad, Vahraz Silva, Arnold GP IEEE TI Microwave power beaming strategies for fractionated spacecraft systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper addresses some issues concerning the application of microwave power beaming in a fractionated spacecraft environment. Some scenarios have been proposed and considered. In one scenario for example, power is distributed in free space from one "mother" spacecraft/satellite to multiple mini spacecraft/satellites in a dynamic environment, where the range and direction of transmission vary in time, and must be accounted for in the optimal energy transmission/distribution. This paper looks at various issues involved, including the type of transmitting antennas (reflectors/phased arrays), the mechanisms of redirecting and/or refocusing the single or multiple beams in the near to mid-field regions of the transmitting antenna. Receiving/rectifying antennas ("rectennas") and other issues of interest and relevance are identified and addressed. The feasibility range and areas of required improvement in terms of antenna elements and other components needed for efficient and robust performance are identified. C1 [Jamnejad, Vahraz; Silva, Arnold] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jamnejad, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 1 Z9 1 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 811 EP 824 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200081 ER PT S AU Deutsch, L Noreen, GK Hamkins, J Stocklin, F Wesdock, J Zillig, D AF Deutsch, Leslie Noreen, Gary K. Hamkins, Jon Stocklin, Frank Wesdock, John Zillig, David GP IEEE TI Selecting codes, modulations, multiple access schemes and link protocols for future NASA missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's Space Communication and Navigation (SCaN) office has been designing an agency-wide space communication and navigation architecture to support NASA space exploration and science missions out to 2030. SCaN chartered a study in 2007 to select codes, modulations, multiple access techniques and link protocols for this architecture. The study was conducted by Goddard Space Flight Center, the Jet Propulsion Laboratory and consultants to NASA. This paper provides an overview of the study, describes the process used to carry out the study, and summarizes study results. Companion papers at this conference provide detailed technical information and analyses. C1 [Deutsch, Leslie; Noreen, Gary K.; Hamkins, Jon] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 238-420, Pasadena, CA 91109 USA. [Stocklin, Frank; Zillig, David] Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Wesdock, John] ITT, Adv Engn & Sci, Herndon, VA 20170 USA. RP Deutsch, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 238-420, Pasadena, CA 91109 USA. EM Gary.K.Noreen@jpl.nasa.gov; Frank.J.Stocklin@nasa.gov; John.Wesdock@itt.com; david.zillig@gsfc.nasa.gov NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 843 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200085 ER PT S AU Stocklin, F Israel, D Deutsch, L Noreen, G Zillig, D Wesdock, J George, N Orr, RS AF Stocklin, Frank Israel, David Deutsch, Leslie Noreen, Gary Zillig, David Wesdock, John George, Nicholas Orr, Richard S. GP IEEE TI Evaluation of multiple access techniques for simultaneous space communications and tracking SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The National Aeronautics and Space Administration has conducted a comprehensive study to identify the most appropriate and efficient modulation, coding, multiple access and link protocol options for future space communication links supported by NASA's Ground Network, Space Network, Deep Space Network, and earth-based ground terminals and in-situ relay satellites envisioned for Constellation Program mission support at the Moon and Mars. This paper 12 briefly describes the study process and summarizes the multiple access recommendations for future NASA space communications. C1 [Stocklin, Frank; Israel, David] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Deutsch, Leslie; Noreen, Gary] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Zillig, David] NASA, Goddard Space Flight Ctr, Perot Syst, Greenbelt, MD 20771 USA. [Wesdock, John; George, Nicholas] ITT Corp, Adv Engn & Sci Div, Herndon, VA 20170 USA. [Orr, Richard S.] SATEL LLC, Rockville, MD 20850 USA. RP Stocklin, F (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Frank.J.Stocklin@nasa.gov; Leslie.J.Deutsch@jpl.nasa.gov; David.J.Zillig@nasa.gov; John.Wesdock@iu.com; Richard.Orr@sa-tel.com NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 876 EP + PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200087 ER PT S AU Hamkins, J Deutsch, L Divsalar, D Dolinar, S Lee, D Stocklin, F Wesdock, J Patel, C AF Hamkins, Jon Deutsch, Leslie Divsalar, Dariush Dolinar, Sam Lee, Dennis Stocklin, Frank Wesdock, John Patel, Chitra GP IEEE TI Formulation of forward error correction coding recommendations for future NASA space communications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA has undertaken a study to recommend and justify Coding, Modulation, and Link Protocol (CMLP) designs for the Space Communications and Networking (SCaN) office (see companion paper [1]). This paper reports on the coding part of the CMLP study, which is chartered with identifying the forward error correction (FEC) codes suitable for NASA space exploration and science missions through 2030. C1 [Hamkins, Jon; Deutsch, Leslie; Divsalar, Dariush; Dolinar, Sam; Lee, Dennis] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Stocklin, Frank] Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Wesdock, John; Patel, Chitra] ITT Ind, Adv Eng & Sci Div, Herndon, VA 20170 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jon.hamkins@jpl.nasa.gov; leslie.deutsch@jpl.nasa.gov; dariush.divsalar@jpl.nasa.gov; sam.dolinar@jpl.nasa.gov; dennis.lee@jpl.nasa.gov; Frank.J.Stocklin@nasa.gov; john.wesdock@itt.com; chitra.patel@itt.com NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 906 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200088 ER PT S AU Allard, D Hutcherson, J AF Allard, Dan Hutcherson, Joseph GP IEEE TI Communications across complex space networks SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Complex space missions face the challenge of reliably maintaining the definition, content and context of information across distributed and evolving space networks. This requires architectural abstractions of information relationships and services (e.g. XML schemas and messaging infrastructures). Over seven years of field study of the SharedNet distributed military communication system, along with Interplanetary Communications Network Infrastructure (ICNI) and Interplanetary Information Services (IIS) space network research efforts have demonstrated the benefits of an Object-Based Communications Architecture (OBCA) for space software development and integration. The OBCA has also been shown to be capable of providing reliable content-based publish-subscribe "need only" data delivery in a space-based communications environment using a JPL developed space link simulator. This paper shall describe findings of these efforts, explain relevant benefits for complex space network communications and suggest further avenues of study in this domain. C1 [Allard, Dan; Hutcherson, Joseph] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Allard, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 931 EP 941 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200090 ER PT S AU Shambayati, S AF Shambayati, Shervin GP IEEE TI Deep-space Ka-band link: Design, continuity and completeness SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Mars Reconnaissance Orbiter (MRO) Ka-band Demonstration has been indefinitely postponed and its objectives must now be met through other means. One of these objectives is the evaluation of the continuity and completeness performance of the deep-space Ka-band link for different link design criteria. To meet this objective, the data from the Water Vapor Radiometers (WVR) and the Advanced Water Vapor Radiometers (AWVR) at the three Deep Space Network (DSN) communication complexes were used. Along with these data, MRO's DSN antenna allocation schedule, Earth-MRO geometry and telecom parameters from MRO were utilized to emulate the Ka-band link performance over a ten-month period. One pass per week per complex was selected for a total of 129 passes (43 passes per complex). For each pass, at most two data rates were chosen such that the expected data return relative to the monthly atmospheric noise temperature distribution for the given complex would be maximized subject to different minimum availability requirements (MARs). The performance of the link was measured in terms of data return, data loss, effective data rate, link availability, number of good periods, number of bad periods, good and bad period duration statistics, number of passes with outages and link stability. As expected, as the MAR was increased, the link availability and link stability increased. However, even with a MAR of 99%, 16 passes suffered outages due to weather effects. The data return remained relatively the same for MARs between 10% and 80% but it declined rapidly as the MAR approached 99%. These results indicate that a simple margin policy cannot guarantee data completeness and retransmissions must be used. Given that some form of retransmission has to be used with Ka-band, it is also recommended that the link be designed with approximately 80% MAR so that the data loss could be reduced substantially without incurring a significant penalty in data return. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shambayati, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 942 EP 952 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200091 ER PT S AU Gal-Edd, J Fatig, CC Miller, R AF Gal-Edd, Jonathan Fatig, Curtis C. Miller, Ron GP IEEE TI Evolution of the lunar network SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA is planning to upgrade its network infrastructure to support missions for the 21(st) century. The first step is to increase the data rate provided to science missions to at least the 100 Mbps range. This is under way, using Ka-band 26 GHz, erecting an 18-meter antenna for the Lunar Reconnaissance Orbiter, and the planned upgrade of the Deep Space Network (DSN) 34-meter network to support the James Webb Space Telescope (JWST). The next step is the support of manned missions to the Moon and beyond. Establishing an outpost with several activities such as rovers, colonization, and observatories, is better achieved by using a network configuration rather than the current method of point-to-point. Another challenge associated with the Moon is communication coverage with the Earth. The Moon's South Pole, targeted for human habitat and exploration, is obscured from Earth view for half of the 28-day lunar cycle and requires the use of lunar relay satellites to provide coverage for the times when there is no direct view of the Earth. The future NASA and Constellation network architecture is described in the Space Communications Architecture Working Group (SCAWG) Report[l]. The Space Communications and Navigation (SCAN) Constellation Integration Project (SCIP) is responsible for coordinating Constellation requirements and has assigned the responsibility for implementing these requirements to the existing NASA communication providers: DSN, Space Network (SN), Ground Network (GN) and the NASA Integrated Services Network (NISN). The SCAWG Report provides a future architecture but does not provide implementation details. The architecture calls for a Netcentric system, using hundreds of 12-meter antennas, a ground antenna array, and a relay network around the Moon. The report did not use cost as a variable in determining the feasibility of this approach. As part of the SCIP Mission Concept Review and the second iteration of the Lunar Architecture Team (LAT), the focus is on cost, as well as communication coverage using operational scenarios. This approach maximizes use of existing assets and adds capability in small increments. This paper addresses architecture decisions such as the Radio Frequency (RF) signal and network (Netcentric) decisions that need to be made and the difficulty of implementing them into the existing Space Network and DSN. It discusses the evolution of the lunar system and describes its components: TDRSS, Earth-based ground stations, Lunar Relay, and surface systems. C1 [Gal-Edd, Jonathan; Miller, Ron] NASA, Goddard Space Flight Ctr, Code 581, Greenbelt, MD 20771 USA. [Fatig, Curtis C.] NASA, Goddard Space Flight Ctr, SAIC, Greenbelt, MD 20771 USA. [Miller, Ron] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gal-Edd, J (reprint author), NASA, Goddard Space Flight Ctr, Code 581, Greenbelt, MD 20771 USA. EM Jonathan.S.Gal-Edd@nasa.gov; curtis.fatig@gsfc.nasa.gov; Ron.a.miller@nasa.gov NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 953 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200092 ER PT S AU Biswas, A Hayden, J Phillips, MS Bhasin, KB Putt, C Sartwell, T AF Biswas, A. Hayden, J. Phillips, M. S. Bhasin, K. B. Putt, C. Sartwell, T. GP IEEE TI Applying DoDAF to NASA Orion mission communication and navigation architecture SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's pursuit of the Vision for Space Exploration (VSE) has motivated the development of an evolvable communication, navigation and timing architecture for crewed missions, initially to the International Space Station (ISS), followed by destinations to the Moon and eventually Mars. A cost-effective, phased development, leveraging to the maximum extent possible existing and upgradable infrastructure, both within and outside NASA, is being emphasized. The transportation of cargo and crew to the ISS using the Crew Exploration Vehicle (CEV), Orion, is currently under development. During this initial mission phase Internet Protocol (IP) based communications, servicing an interoperable System-of-Systems will be developed. The Department of Defense Architecture Framework (DoDAF) processes and prescribed products therein are being used to implement an end-to-end architecture developed using NASA System Engineering practices. In this paper we will provide an overview of the architecting process with a few examples of the NASA applied DoDAF products. C1 [Biswas, A.] NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Hayden, J.] 5467 S Goddard Rd, Littleton, CO 80123 USA. [Phillips, M. S.; Sartwell, T.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Bhasin, K. B.; Putt, C.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Biswas, A (reprint author), NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM abiswas@jpl.nasa.gov; jhayden@earthlink.net; Michael.S.Phillips@nasa.gov; Kul.B.Bhasin@nasa.gov; cputt@msn.com; Tom.Sartwell@gdc4s.com FU National Aeronautics and Space Administration FX The work described was carried out jointly by the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. NR 8 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 985 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200094 ER PT S AU Nguyen, S Okino, C Cheng, M AF Nguyen, Sam Okino, Clayton Cheng, Michael GP IEEE TI Intelligibility and space-based voice with relaxed delay constraints SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In this paper, we leverage the long range end-to-end scenarios envisioned for lunar and beyond voice conversations by allowing non-traditional additional processing delay for quasi-real-time voice conversations. The concept of improving the quality of end-to-end voice conversations for long delay environments is considered by utilizing Luby Transforms on the Conjugate-Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP) codec. In addition, this paper also examines the use of automated speech recognition software as a means of generating a quantifiable metric for speech intelligibility in the spirit of the Diagnostic Rhyme Test (DRT). C1 [Nguyen, Sam; Okino, Clayton; Cheng, Michael] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nguyen, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1007 EP 1012 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200096 ER PT S AU Spearman, W Martin, J Gao, JL AF Spearman, Will Martin, Jim Gao, Jay L. GP IEEE TI Adaptive QoS in 802.11e wireless networks for lunar communications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Lunar surface communications present specific problems that can be solved with well established terrestrial networking standards such as 802.11. Unfortunately, 802.11 has limitations regarding high priority traffic such as voice and command data which are sensitive to jitter, delay, and loss. The IEEE 802.11e standard provides enhancements that allow traffic with specific needs to be differentiated from normal traffic. While these enhancements have been shown to effectively improve latency and throughput or high priority traffic, they do not offer precise nor consistent control of performance levels. In this paper capacity and priority are explored in the context of lunar communications using 802.11g with 802.11e. We present a method to dynamically optimize 802.11e contention parameters to provide more granular control over the network's quality of service (QoS) for the various flow types. A distributed adaptive algorithm that extends 802.11e's Enhanced Distributed Channel Access (EDCA) is presented. We show that the enhancement provides more granular and consistent performance than that provided by the static algorithm used in standard 802.11e. C1 [Spearman, Will; Martin, Jim] Clemson Univ, Sch Comp, Clemson, SC 29632 USA. [Gao, Jay L.] Jet Prop Lab, Pasadena, CA 91109 USA. RP Spearman, W (reprint author), Clemson Univ, Sch Comp, Clemson, SC 29632 USA. EM wspearm@cs.clemson.edu; jim.martin@cs.clemson.edu; Jay.L.Gao@jpl.nasa.gov FU Clemson University under the South Carolina Space Grant Consortium Research and Education Awards Program (REAP); National Aeronautics and Space Administration FX The research described in this paper was carried out at Clemson University under the South Carolina Space Grant Consortium Research and Education Awards Program (REAP) and at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1022 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200098 ER PT S AU Stoenescu, T Clare, L AF Stoenescu, Tudor Clare, Loren GP IEEE TI Traffic modeling for NASA's space communications and navigation (SCaN) network SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB IP-based communications technologies are being implemented for space applications, including NASA's Constellation Program and its efforts toward returning humans to the Moon. In order to be able to accurately estimate performance, models have been developed that characterize the types of offered traffic that will occur.(12) Voice and real-time motion imagery (video) models have been specifically developed due to their importance, in addition to general models for telemetry and command data flow. Synthesized traffic may be generated from these models and aggregated to build representative loads on the communications transport resources for performance characterization. C1 [Stoenescu, Tudor; Clare, Loren] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stoenescu, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1035 EP 1048 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200099 ER PT S AU Segui, JS AF Segui, John S. GP IEEE TI Demand access protocol design and validation with SPIN SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In order for distributed systems to communicate reliably engineers standardize on communication rules (or protocols). Unforeseen behavior in communication protocols can push faults up to applications resulting in uncontrollable systems and should not be tolerated. However, while most modem protocols undergo extensive testing, rigorous formal methods, such as model checking, are rarely used due to complexity and intractable state spaces. Nevertheless, starting formal validation early in the development cycle provides less-complexity, significantly smaller state spaces and can allow for full validation. As a side benefit early error detection and correction costs significantly less than redesigns later in a system's life-cycle. This paper discusses the preliminary design and validation of the Demand Access Protocol (DAP) using the SPIN model checker. Using English language specifications and flow charts, the author developed a PROMELA (the language used by SPIN) specification and tested basic safety properties. Used correctly, a model checker can thoroughly validate complex systems and guarantee absence of fault conditions. C1 CALTECH, Jet Prop Lab, Commun Networks Grp, Pasadena, CA 91109 USA. RP Segui, JS (reprint author), CALTECH, Jet Prop Lab, Commun Networks Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1049 EP 1056 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200100 ER PT S AU Jennings, E Heckman, D AF Jennings, Esther Heckman, David GP IEEE TI Performance characterization of space communications and navigation (SCaN) network by simulation SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB As future space exploration missions will involve larger number of spacecraft and more complex systems, theoretical analysis alone may have limitations on characterizing system performance and interactions among the systems. Simulation tools can be useful for system performance characterization through detailed modeling and simulation of the systems and its environment. To simulate Space-based networks, we have developed the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE) tool which captures the unique characteristics of space networking for performance assessment and end-to-end test evaluation. This tool contains orbital and planetary motion kinematics models, link engineering models, traffic load generation models and communication protocol models. This paper reports the simulation of the Orion (Crew Exploration Vehicle) to the International Space Station (ISS) mission where Orion is launched by Ares into orbit on a 14-day mission to rendezvous with the ISS. Communications services for the mission are provided by the Space Communication and Navigation (SCaN) network infrastructure which includes the NASA Space Network (SN), Ground Network (GN) and NASA Integrated Services Network (NISN). The objectives of the simulation are to determine whether SCaN can meet the communications needs of the mission, to demonstrate the benefit of using QoS prioritization, and to evaluate network key parameters of interest such as delay and throughput. C1 [Jennings, Esther; Heckman, David] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jennings, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1063 EP 1071 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200102 ER PT S AU Pang, J Gilbert, T AF Pang, Jackson Gilbert, Tyler GP IEEE TI Assessing the minimum bandwidth requirement for transmitting MPEG-4 over space SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The use of MPEG-4 for both scientific analysis and public outreach in the next phase of NASA Space missions is considered and the minimum bandwidth required is assessed. The video contents typical to the mission scenarios are analyzed to provide the tuning parameters for the video encoding process and the quality of service required at the IP network layer. Realistic space link simulation is then used to generate a-priori video quality assessment for a given set of space link conditions. The intent of this study is to provide the basis for tradeoff between bandwidth allocation for video traffic and quality of the video. C1 [Pang, Jackson] CALTECH, NASA Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Gilbert, Tyler] Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. RP Pang, J (reprint author), CALTECH, NASA Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Jackson.Pang@jpl.nasa.gov; tgil@stanford.edu FU Jet Propulsion Laboratory, California Institute of Technology,; National Aeronautics and Space Administration FX The authors would like to thank Jay Gao for his contribution on quality of service usage over space links. We also thank our colleagues at NASA Johnson Space Center's Imagery Services for providing the ISS and Shuttle mission video clips. The research described in this paper was partially carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1072 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200103 ER PT S AU Malekpour, MR AF Malekpour, Mahyar R. GP IEEE TI Verification of a Byzantine-fault-tolerant self-stabilizing protocol for clock synchronization SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper presents the mechanical verification of a simplified model of a rapid Byzantine-fault-tolerant self-stabilizing protocol for distributed clock synchronization systems. This protocol does not rely on any assumptions about the initial state of the system except for the presence of sufficient good nodes, thus making the weakest possible assumptions and producing the strongest results. This protocol tolerates bursts of transient failures, and deterministically converges within a time bound that is a linear function of the self-stabilization period. A simplified model of the protocol is verified using the Symbolic Model Verifier (SMV) [1]. The system under study consists of 4 nodes, where at most one of the nodes is assumed to be Byzantine faulty. The model checking effort is focused on verifying correctness of the simplified model of the protocol in the presence of a permanent Byzantine fault as well as confirmation of claims of determinism and linear convergence with respect to the self-stabilization period. Although model checking results of the simplified model of the protocol confirm the theoretical predictions, these results do not necessarily confirm that the protocol solves the general case of this problem. Modeling challenges of the protocol and the system are addressed. A number of abstractions are utilized in order to reduce the state space. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Malekpour, MR (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1085 EP 1097 PG 13 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200104 ER PT S AU Israel, DJ Marquart, JK Thompson, WL AF Israel, David J. Marquart, Jane K. Thompson, Willie L., II GP IEEE TI The GSFC Communications, Standards, and Technology Laboratory (CSTL) SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The NASA Goddard Space Flight Center (GSFC) has created the Communications, Standards, and Technology Lab (CSTL) for the investigation, development, and demonstration of new communications standards and technologies. The testbed combines elements from the Microwave & Communications Systems Branch lab with the Flight Software Branch lab to form an end-to-end communications scenario. The testbed is currently configured to demonstrate communications, using the Internet Protocol, for the Crew Exploration Vehicle (CEV) and Lunar Surface Access Module (LSAM).(1,2) The Radio Frequency (RF) systems in the CSTL are implemented using software defined radio (SDR) technology and NASA engineering model transponders. Various link layer, modulation and coding schemes have been developed and tested, including the Tracking and Data Relay Satellite System (TDRSS) spread spectrum waveforms. Flight components include mission flight software and hardware, onboard LANs, space-qualified routers, voice and video simulators. New and proposed applications and transport protocols are being tested for flight worthiness. The ground support system includes both Government-off-the-Shelf (GOTS) and Commercial-off-the-Shelf (COTS) command/telemetry equipment. This paper highlights the current capabilities of the CSTL and will present an overview of previous CSTL activities and results, as well as planned future work and opportunities. C1 [Israel, David J.; Thompson, Willie L., II] NASA, Goddard Space Flight Ctr, Microwave & Commun Syst Branch, Code 5673, Greenbelt, MD 20771 USA. [Marquart, Jane K.] NASA, Goddard Space Flight Ctr, Flight Software Branch, Greenbelt, MD 20771 USA. RP Israel, DJ (reprint author), NASA, Goddard Space Flight Ctr, Microwave & Commun Syst Branch, Code 5673, Greenbelt, MD 20771 USA. EM dave.israel@nasa.gov; jane.k.marquart@nasa.gov; wilhe.l.thompson@nasa.gov NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1105 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200106 ER PT S AU Lee, CH AF Lee, Charles H. GP IEEE TI On the optimal extension of ground network stations to support NASA's lunar exploration SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's Vision for Space Exploration is to establish a permanent human presence on the Moon beginning no later than 2020. Its initial base is centered at the lunar South Pole and its subsequent sorties and outposts could practically be anywhere on the lunar surface, including the far side. From time to time, there will be a Crew Exploration Vehicle at the Moon exchanging astronauts using a Lunar Surface Access Module. It is also proposed to deliver one to two Lunar Relay Satellites to the Moon to increase the connectivity between the Earth ground stations and the users on or near the Moon as well as to alleviate the lunar spacecraft burdens, such as mass and power. As a result, there will be critical periods when multiple spacecrafts at the Moon require simultaneous coverage.(12) Due to the allocated frequencies for lunar missions, the aperture sizes of the Deep Space Network (DSN) antennas, and the Earth-Moon distance, the coverage by the DSN antennas for the Moon are limited and thus one DSN station cannot effectively support multiple spacecrafts at the Moon. In other words, each lunarcraft may require its own ground station. Building more antennas at existing sites may not be an appropriate solution. Namely, the current DSN sites at Goldstone, Canberra, and Madrid cannot continuously cover the Moon due to the proximity of the Moon to Earth and the imperfect separation between Canberra and Madrid (>120 degrees). In addition, site diversity may also be needed, due to the fact that the Ka-band (37/40 GHz) is quite sensitive to weather. Thus there is a definite need to expand the diversity of the ground network to support NASA's future lunar exploration. In this paper, we perform the trade study to extend the diversity of the current DSN baseline ground stations to support multiple concurrent missions at the Moon. Candidates of particular interest include (1) Hartebeesthoek, South Africa, (2) Santiago, Chile, (3) Usuda, Japan, (4) Dongara, Australia, and (5) the White Sands Complex, New Mexico. These sites were selected because they are existing facilities, expandable and complementary with other existing sites, and located in an environment with suitable weather conditions. Numerical simulations over a period of 12 years are performed using different combination of sites. Multiple and simultaneous coverage percentages and the maximum communications time gaps are calculated and are used in the fitness function to assess the suitability of the candidate ground sites. Our findings provide the insight of number of stations and the corresponding locations that will provide optimal ground support and network expandability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1112 EP 1117 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200107 ER PT S AU Thompson, WL Israel, DJ AF Thompson, Willie L., II Israel, David J. GP IEEE TI Adaptive power control for space communications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper investigates the implementation of power control techniques for crosslinks communications during a rendezvous scenario of the Crew Exploration Vehicle (CEV) and the Lunar Surface Access Module (LSAM). During the rendezvous, NASA requires that the CEV supports two communication links: space-to-ground and crosslink simultaneously. The crosslink will generate excess interference to the space-to-ground link as the distances between the two vehicles decreases, if the output power is fixed and optimized for the worst-case link analysis at the maximum distance range. As a result, power control is required to maintain the optimal power level for the crosslink without interfering with the space-to-ground link. A proof-of-concept will be described and implemented within Goddard Space Flight Center (GSFC) Communications, Standard, and Technology Lab (CSTL). C1 [Thompson, Willie L., II; Israel, David J.] NASA, Goddard Space Flight Ctr, Microwave & Commun Syst Branch, Greenbelt, MD 20771 USA. RP Thompson, WL (reprint author), NASA, Goddard Space Flight Ctr, Microwave & Commun Syst Branch, Code 5673, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1161 EP 1165 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200113 ER PT S AU Bagri, DS AF Bagri, D. S. GP IEEE TI Same beam tracking with the proposed DSN array using calibration signal from multiple sources SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The accuracy of tracking measurements using very long baseline interferometer (VLBI) is seriously limited due to angular and temporal separation between the calibration and spacecraft measurements. Same beam interferometry, where the calibration source is in the same primary beam as the spacecraft being observed eliminates temporal affects and considerably reduces calibration errors due to reduced angular separation between the calibrator and the spacecraft which minimizes errors due to propagation variations and uncertainty in geometry between source and baseline. With the current measurement methods this requires having a suitable calibration source of enough signal strength within the primary beam of the antennas used for the inteferometry measurements. Normally such sources are not available because of a low number density of suitable strong calibration sources. However there are many more weaker calibration sources and it may be possible to use combined signal from a number of weaker sources within the primary beam of the antennas if a single strong source is not available within the primary beam at any time. The probability of having enough combined total signal increases considerably if we accept using multiple calibration sources. Expected accuracy of a tracking measurement using signal from multiple calibration sources should be similar to the accuracy expected with a single calibration source within the beam, if the total combined signal from the individual weaker sources is similar to the desired single source. An important point that is worth noting here is that if we want to take advantage of utilizing the same beam interferometry for accurate spacecraft tracking most of the times, then the diameter of the antennas of the proposed array-based deep space network (DSN Array) should be limited to as small a value as practical to give a large field of view. This would enable having suitable calibration source(s) within the primary beam of the antennas. Considering practical aspects it appears that the diameter for the proposed DSN Array antenna should be limited to a maximum of about 12m. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bagri, DS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1177 EP 1181 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200115 ER PT S AU Majid, WA Bagri, DS AF Majid, Walid A. Bagri, Durgadas S. GP IEEE TI Precision spacecraft tracking using in-beam phase referencing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID COUNTS; GHZ AB The Deep Space Network (DSN) Array of the future provides an intriguing possibility of using the techniques of in-beam phase referencing to determine the angular position of spacecraft with accuracy at the level of 0.1 nano-radian (nrad). In this paper, we discuss the prospects for carrying out such measurements at both 8.4 GHz (X-band) and 32 GHz (Ka-band). Our study suggests that at X-band in-beam calibration may be available as an astrometric tool over 20-30 percent of the sky. The prospects at Ka-band, on the other hand, are not very hopeful. We point out that these estimates depend strongly on the number density of compact sources at the 1-mJy level. We also present the results from our recent VLBA (Very Long Baseline Array) observations at X-band, which has determined the compact source density at the 10-mJy level and discuss future observations to probe weaker source population. Finally, we discuss issues related to phase cycle ambiguity resolution and potential techniques to resolve them. C1 [Majid, Walid A.; Bagri, Durgadas S.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Majid, WA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1182 EP 1188 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200116 ER PT S AU Orr, RS Divsalar, D AF Orr, Richard S. Divsalar, Dariush GP IEEE TI Combined GMSK modulation and PN ranging for communications and navigation SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Renewed interest in human exploration of space suggests a future need for high throughput earth-space links. Anticipating crowding within spectrum used for deep-space communications, particularly at X-band, NASA is investigating the use of bandwidth-efficient modulation (BEM). Requirements for trajectory/orbit determination and vehicle guidance will persist, however, implying that signals for radiometric tracking must coexist with communications within the available spectrum. Because navigation signals in current use may be insufficiently compatible with BEM, the question arises as to how to combine ranging and BEM communications. This paper presents one waveform approach potentially applicable to the space-to-earth return link problem. GMSK modulation is combined with a pseudonoise (PN) ranging signal on a subcarrier. Waveform parameters are adjusted to achieve: (1) a constant-envelope waveform; (2) adequate separation between the communications and ranging components; (3) high data rates (similar to 6 Msps); and (4) conformance to international standards such as Space Frequency Coordination Group (SFCG).(1) We define the waveform, present its power spectrum, exhibit receiver structures for simultaneous GMSK data demodulation and PN tracking for accurate time-of-arrival estimation, and show relationships among the waveform parameters that must hold to satisfy the demands of applicable standards.(2) C1 [Orr, Richard S.] SATEL LLC, 9700 Great Seneca Highway, Rockville, MD 20850 USA. [Divsalar, Dariush] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Orr, RS (reprint author), SATEL LLC, 9700 Great Seneca Highway, Rockville, MD 20850 USA. EM richard.orr@satel.com; dariush.divsalar@jpl.nasa.gov FU Jet Propulsion Laboratory, California Institute of Technology; NASA FX This research in part was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1197 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200118 ER PT S AU Ivancic, W AF Ivancic, William GP IEEE TI Problems with deployment of multi-domained, multi-homed mobile networks SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This document describes numerous problems associated with deployment of multi-homed mobile platforms consisting of multiple networks and traversing large geographical areas. The purpose of this document is to provide insight to real-world deployment issues and provide information to groups that are addressing many issues related to multi-homing, policy-base routing, route optimization and mobile security - particularly those groups within the Internet Engineering Task Force.(12). C1 NASA Glenn Res Ctr, Networking & Adv Commun Technol Dev, Cleveland, OH 44135 USA. RP Ivancic, W (reprint author), NASA Glenn Res Ctr, Networking & Adv Commun Technol Dev, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 16 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1421 EP 1428 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200141 ER PT S AU Kerczewski, RJ Budinger, JM Gilbert, TJ AF Kerczewski, Robert J. Budinger, James M. Gilbert, Tricia J. GP IEEE TI Technology assessment results of the Eurocontrol/FAA future communications study SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The US Federal Aviation Administration (FAA) and Eurocontrol jointly initiated the Future Communications Study (FCS) to develop a common approach for a globally harmonized air traffic management (ATM) communications system. The FCS includes operational concepts and communications requirements development, analysis of business and institutional elements, and identification and assessment of technology alternatives. The FCS technology assessment determined the best set of available technologies for aviation safety communications for ATM given key constraints such as cost, transition feasibility, technical requirements, and spectrum availability. From 2004 to 2007, the assessment progressed in three phases, yielding technical results and recommendations for development and phased implementation of a future aviation communications infrastructure. C1 [Kerczewski, Robert J.; Budinger, James M.] NASA, Glenn Res Ctr, Adv CNS Architectures & Syst Technol ACAST Projec, Cleveland, OH USA. [Gilbert, Tricia J.] ITT Corp, White Plains, NY 10604 USA. RP Kerczewski, RJ (reprint author), NASA, Glenn Res Ctr, Adv CNS Architectures & Syst Technol ACAST Projec, Cleveland, OH USA. EM rkerczewski@nasa.gov; james.m.budinger@nasa.gov; tricia.gilbert@itt.com NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1438 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200143 ER PT S AU Norton, CD Fang, HF Michel, T Moussessian, A Schiermeier, J Springer, P Otero, R AF Norton, Charles D. Fang, Houfei Michel, Thierry Moussessian, Alina Schiermeier, John Springer, Paul Otero, Richard GP IEEE TI Model-based verification and validation of component structures for RF and optical experimental systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Future large aperture systems will depend on integrated modeling to assess key performance parameters for designs that cannot be fully tested and verified before flight. Achieving this goal will require integrating component models, results from numerical simulations, and physical tests to predict the performance and prove the viability of such systems within numerous model and measurement uncertainties. We will describe the use of JPL's Precision Environment Test Enclosure (PETE) with integrated modeling for radar component and optical metrology experiments to validate models for predictive analysis of large aperture systems.(12). C1 [Norton, Charles D.; Fang, Houfei; Michel, Thierry; Moussessian, Alina; Schiermeier, John; Springer, Paul] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Otero, Richard] Georgia Inst Technol, Atlanta, GA 30332 USA. RP Norton, CD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Charles.D.Norton@jpl.nasa.gov FU JPL Research and Technology Development Program; Georgia Space Grant Consortium; ATK Space. FX This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. It was support by the JPL Research and Technology Development Program. We also acknowledge technical support from Greg Agnes, Keats Wilkie, Rebecca Tanimoto, Case Bradford, Feng Zhao, Dave Murphy, and Thomas Cwik. We also acknowledge support from the Georgia Space Grant Consortium and ATK Space. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1467 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200146 ER PT S AU Tratt, DM Amzajerdian, F Kashem, NB Stephen, MA Shapiro, AA Mense, AT AF Tratt, David M. Amzajerdian, Farzin Kashem, Nasir B. Stephen, Mark A. Shapiro, Andrew A. Mense, Allan T. GP IEEE TI Promoting robust design of diode lasers for space: A national initiative SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID EARTH-SCIENCE ENTERPRISE AB The Diode-laser Array Working Group (DAWG) is a national-level consumer/provider forum for discussion of engineering and manufacturing issues which influence the reliability and survivability of high-power broad-area laser diode devices in space, with an emphasis on laser diode arrays (LDAs) for optical pumping of solid-state laser media. The goals of the group are to formulate and validate standardized test and qualification protocols, operational control recommendations, and consensus manufacturing and certification standards. Reliability and lifetime data collected by laser diode manufacturers and the user community are being used to develop standardized guidelines for specifying and qualifying laser diodes for long-duration operation in space. Effective implementation of statistical design techniques at the supplier design, development, and manufacturing levels will aid in reducing product performance variability and improve product reliability for diodes employed in space applications. The ultimate goal is to promote an informed U.S. Government investment and procurement strategy for assuring the availability and durability of space-qualified LDAs. C1 [Tratt, David M.] Aerosp Corp, Civil & Commercial Operat Div, 200 S Los Robles Ave,Suite 150, Pasadena, CA 91101 USA. [Amzajerdian, Farzin] NASA, Langley Res Ctr, Hampton, VA 23681 USA. [Kashem, Nasir B.; Stephen, Mark A.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Shapiro, Andrew A.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. [Mense, Allan T.] Raytheon Co, Tucson, AZ 85706 USA. RP Tratt, DM (reprint author), Aerosp Corp, Civil & Commercial Operat Div, 200 S Los Robles Ave,Suite 150, Pasadena, CA 91101 USA. EM David.M.Tratt@aero.org; F.Amzajerdian@nasa.gov; Nasir.B.Kashem@nasa.gov; Mark.A.Stephen@nasa.gov; Andrew.A.Shapiro@jpl.nasa.gov; Allan_T_Mense@raytheon.com FU Laser Risk Reduction Program - NASA Earth Science Technology Office FX Working group activities at the NASA Langley Research Center and NASA Goddard Space Flight Center are supported under the Laser Risk Reduction Program, sponsored by the NASA Earth Science Technology Office. NR 20 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1487 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200147 ER PT S AU Green, RO Pieters, C Mouroulis, P Koch, T AF Green, Robert O. Pieters, Carle Mouroulis, Pantazias Koch, Timothy GP IEEE TI Moon mineralogy mapper Imaging spectrometer science measurements SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Moon Mineralogy Mapper (M3) was selected as a NASA Discovery Mission of Opportunity in early February 2005 and entered phase B in May 2005. The primary science goal is to characterize and map the lunar surface composition in the context of its geologic evolution. The primary exploration goal is to assess and map the Moon mineral resources at high spatial resolution to support planning for future, targeted missions. The M3 science instrument is a high uniformity and high precision imaging spectrometer of the pushbroom type operating in the solar reflected energy portion of the electromagnetic spectrum. M3 is planned to be launched as a guest instrument on the Chandrayaan-1 mission of the Indian Space Research Organization (ISRO) in early 2008. As a guest instrument, M3 was required to be low mass, low volume and low power. Yet, the imaging spectroscopy science required a broad spectral range, excellent radiometric precision and unmatched uniformity. The complete M3 instrument measures the spectral range from 430 to 3000 run at 10 nm sampling, with a 24-degree cross-track field-of-view and 0.7 milliradian sampling as well as greater than 90% spectral cross-track uniformity and 90% spectral IFOV uniformity. The mass and power of the M3 instrument are 8.3 kilograms and 16 Watts average. The volume of the optical and detector assembly is 25 X 18 X 12 centimeters. The M3 instrument preship review was successfully completed on the 3rd of May 2007. In this paper, the M3 characteristics and initial laboratory calibration results are presented.(12). C1 [Green, Robert O.; Mouroulis, Pantazias; Koch, Timothy] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Pieters, Carle] Brown Univ, Providence, RI 02912 USA. RP Green, RO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rog@jpl.nasa.gov FU NASA Discovery Program FX We thank NASA Discovery Program for supporting M3development, implementation and science. A portion of this work was carried out at the Jet Propulsion Laboratory / California Institute of Technology, Pasadena, California, under contract with the National Aeronautics and Space Administration. We are honored to be part of ISRO's Chandrayaan- 1 mission. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1504 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321200149 ER PT S AU Ismail, S Koch, G Abedin, N Refaat, T Rubio, M Singh, U AF Ismail, Syed Koch, Grady Abedin, Nurul Refaat, Tamer Rubio, Manuel Singh, Upendra GP IEEE TI Development of laser, detector, and receiver systems for an atmospheric CO2 lidar profiling system SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID CARBON-DIOXIDE; VARIABILITY; CYCLE AB A ground-based Differential Absorption Lidar (DIAL) is being developed with, the capability to measure range-resolved and column amounts of atmospheric CO2. This system is also capable of providing high-resolution aerosol profiles and cloud distributions. It is being developed as part of the NASA Earth Science Technology Office's Instrument Incubator Program. This three year program involves the design, development, evaluation, and fielding of a ground-based CO2 profiling system. At the end of a three-year development this instrument is expected to be capable of making measurements in the lower troposphere and boundary-layer where the sources and sinks of CO2 are located. It will be a valuable tool in the validation of NASA Orbiting Carbon Observatory (OCO) measurements of column CO2 and suitable for deployment in the North American Carbon Program (NACP) regional intensive field campaigns. The system can also be used as a test-bed for the evaluation of lidar technologies for space-application. (1) (2). C1 [Ismail, Syed; Koch, Grady; Abedin, Nurul; Rubio, Manuel; Singh, Upendra] NASA, Langley Res Ctr, Hampton, VA 23681 USA. [Refaat, Tamer] Old Dominion Univ, Norfolk, VA 23529 USA. RP Ismail, S (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM Syed.Ismail-1@nasa.gov; Grady.j.Koch@nasa.gov; m.n.abedin@nasa.gov; Manuel.a.rubio@nasa.gov; Upendra.n.singh@nasa.gov; trefaat@jlab.org FU 2-ptm CO2 DIAL IIP Project under NASA's Earth Science Technology Office. FX This work is supported by 2-ptm CO2 DIAL IIP Project under NASA's Earth Science Technology Office. The authors would like to thanks Terry Mack for developing phototransistor electronics and also optimizing post detector electronics; Bruce Barnes for development of data acquisition software; Yonghoon Choi and Stephanie Vay for providing in situ data for comparison with DIAL measurements; and Shane Mayor, Scott Spuler and NCAR management for their support and facilities for conducting detector tests at NCAR, Boulder, CO. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1527 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201004 ER PT S AU Allan, GR Riris, H Abshire, JB Sun, XL Wilson, E Burris, JF Krainak, MA AF Allan, Graham R. Riris, Haris Abshire, James B. Sun, Xiaoli Wilson, Emily Burris, John F. Krainak, Michael A. GP IEEE TI Laser sounder for active remote sensing measurements of CO2 concentrations SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID ABSORPTION-SPECTROSCOPY; MODULATION AB We report on progress of our CO2 laser sounder laboratory breadboard system the goal of which is to measure the integrated column abundance of CO2 to better than 1 ppm from low Earth orbit globally, measuring at all latitudes and seasons through day and night. The challenge for an orbiting CO2 instrument is to achieve high precision not high sensitivity. We have made simple yet significant improvements to our active, optical-sensing laser-sounder instrument and real-time data processing that now enables absolute absorption measurements to better than +/- 0.05% for over 10 hours before re-calibration (equivalent to a 1ppm precision from orbit). Data from an eight day, 0.8 Km open path comparison test with a LICOR shows excellent agreement. (12). C1 [Allan, Graham R.] NASA, Goddard Space Flight Ctr, Sigma Space Inc, Mail Code 694, Greenbelt, MD 20771 USA. [Riris, Haris; Abshire, James B.; Sun, Xiaoli; Burris, John F.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Wilson, Emily; Krainak, Michael A.] NASA, Goddard Space Flight Ctr, Laser & Electro Opt Branch, Greenbelt, MD 20771 USA. RP Allan, GR (reprint author), NASA, Goddard Space Flight Ctr, Sigma Space Inc, Mail Code 694, Greenbelt, MD 20771 USA. EM graham.allan@gsfc.nasa.gov RI Wilson, Emily/C-9158-2012; Sun, Xiaoli/B-5120-2013; Riris, Haris/D-1004-2013; Abshire, James/I-2800-2013; Allan, Graham/D-3905-2013 OI Wilson, Emily/0000-0001-5634-3713; NR 9 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1534 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201005 ER PT S AU Stephen, MA Mao, J Abshire, JB Kawa, SR Sun, X Krainak, MA AF Stephen, Mark A. Mao, Jianping Abshire, James B. Kawa, S. Randy Sun, Xiaoli Krainak, Michael A. GP IEEE TI Oxygen spectroscopy laser sounding instrument for remote sensing of atmospheric pressure SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID DIFFERENTIAL ABSORPTION LIDAR AB We report on the progress of an Oxygen spectroscopy laser sounding instrument designed as a calibration channel for a carbon dioxide (CO2) laser sounding instrument. We have developed a pulsed, frequency-doubled, fiber laser transmitter for use in an oxygen instrument. The instrument concept uses the pressure broadening of spectroscopic lines of the diatomic oxygen A-band to deduce atmospheric pressure. There are many uses for this measurement but we are developing it primarily to make a measurement of the dry mixing ratio of CO2. The CO2 measurement can be affected by changes in atmospheric properties such as humiditiy, temperature and pressure. To remove these variances requires measuring a stable, well-mixed gas like Oxygen. We will report on the basic theory behind the instrument, measurements made at a test site at Goddard, review the current state of the instrument technologies and the necessary steps to bring them to space readiness, and review the current state of the instrument development. C1 [Stephen, Mark A.; Abshire, James B.; Kawa, S. Randy; Sun, Xiaoli; Krainak, Michael A.] NASA, Goddard Space Flight Ctr, Code 554, Greenbelt, MD 20771 USA. [Mao, Jianping] RSIS, Greenbelt, MD 20771 USA. RP Stephen, MA (reprint author), NASA, Goddard Space Flight Ctr, Code 554, Greenbelt, MD 20771 USA. EM mark.a.stephen@nasa.gov; jmao@pop600.gsfc.nasa.gov; James.B.Abshire.1@gsfc.nasa.gov; Stephan.R.Kawa@gsfc.nasa.gov; Xiaoli.Sun@gsfc.nasa.gov; mkrainak@pop500.gsfc.nasa.gov RI Kawa, Stephan/E-9040-2012; Abshire, James/I-2800-2013 NR 14 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1541 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201006 ER PT S AU Spinhime, JD AF Spinhime, James D. GP IEEE TI Performance of the GLAS satellite lidar cloud and aerosol measurements SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Launched in early 2003, the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and Land Elevation Satellite is the first polar orbiting satellite lidar and is intended for comprehensive earth science applications covering surface altimetry for ice sheets and vegetation and atmospheric profiling. The instrument design includes high performance observations of the distribution and optical scattering cross sections of atmospheric clouds and aerosol. The backscatter lidar operates at two wavelengths, 532 and 1064 nm. For the atmospheric cloud and aerosol measurements, the 532 nm channel was designed for ultra high efficiency with solidstate photon counting detectors and etalon filtering. Data processing algorithms were developed to calibrate and normalize the signals and produce global scale data products of the height distribution of cloud and aerosol layers and their optical depths and particulate scattering cross sections up to the limit of optical attenuation. Since the initial production of data products there has been extensive studies of the accuracy and limitation of the data products. Studies include the statistical analysis of results, quality checking surveys and inter-comparison to ground and airborne measurements. The paper concentrates on the effectiveness, results and limitations of the atmospheric lidar channel design and data product algorithms. Overall, given known instrument problems uncorrected before launch, the results validate the expectations of the lidar design. (12). C1 NASA, Goddard Space Flight Ctr, Lab Atmospheres 613 1, Greenbelt, MD 20771 USA. RP Spinhime, JD (reprint author), NASA, Goddard Space Flight Ctr, Lab Atmospheres 613 1, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1547 EP 1554 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201007 ER PT S AU Liebe, CC Abramovici, A Bartman, RK Chapsky, J Chapsky, L Coste, K Lam, R AF Liebe, Carl Christian Abramovici, Alex Bartman, Randall K. Chapsky, Jacob Chapsky, Lars Coste, Keith Lam, Raymond GP IEEE TI Optical metrology system for radar phase correction on large flexible structure SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In aerospace applications there is an increasing interest in metrology systems. Metrology systems are used in applications such as wave front correction and formation flying, for measuring deployable structure deformation/oscillations, and as the crude stage for interferometer missions. In this paper we describe a concept for a metrology system. The metrology system concept will be able to determine the Cartesian (x,y,z) coordinates of 100+ fiducials to an accuracy of 1 mm with an update rate of 10 Hz. Considerable deployment uncertainty can be accepted. The system operates by laser illuminated fiducials feed though optical fibers. One fiducial. is illuminated at a time. A camera reads the transverse position of the fiducial, and the distance to the fiducial is determined by modulating the laser light and measuring a phase difference. The inertial orientation of the structure is measured by imaging the stars. A metrology system as described is essential to a radar antenna on a large flexible structure. C1 [Liebe, Carl Christian; Abramovici, Alex; Bartman, Randall K.; Chapsky, Jacob; Coste, Keith; Lam, Raymond] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Chapsky, Lars] Columbus Technol & Serv Inc, Pasadena, CA 91101 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM carl.c.liebe@jpl.nasa.gov FU DARPA; Raytheon Company FX The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology and was sponsored by DARPA and the Raytheon Company. References herein to any specific commercial product, process or service by trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, Raytheon or the Jet Propulsion Laboratory, California Institute of Technology. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1561 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201009 ER PT S AU Liebe, CC Alexander, JW Scherr, L AF Liebe, Carl Christian Alexander, James W. Scherr, Larry GP IEEE TI Sun Imaging though the Martian atmosphere SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper discusses the sun images acquired with the panoramic cameras (pancam) on the Mars Exploration Rovers. The mission goals, the camera design, the data processing and the results are discussed. Each of the two rovers has two cameras, one with a bandpass filter centered at 880 mn and one centered at 440 mn. It is observed that some of the pancams show ghost images. Based on analysis of the images, the transparency of the Martian atmosphere (tau) is estimated to be similar to 0.9. A seasonal change in tau is observed. C1 [Liebe, Carl Christian; Alexander, James W.; Scherr, Larry] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1630 EP 1640 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201017 ER PT S AU Bekker, DL Lukowiak, M Shaaban, M Blavier, JFL Pingree, PJ AF Bekker, Dmitriy L. Lukowiak, Marcin Shaaban, Muhammad Blavier, Jean-Francois L. Pingree, Paula J. GP IEEE TI A hybrid-FPGA system for on-board data processing targeting the MATMOS FTIR instrument SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The MATMOS Fourier Transform Infrared (FTIR) spectrometer is one of three scientific instruments on the previously proposed MARVEL mission. MATMOS requires computationally intensive floating-point signal processing to reduce the amount of data prior to downlink. With the goal of reducing design time and the size and weight of instrument electronics, this paper presents an FTIR spectrometry implementation targeting the Xilinx Virtex-4FX hybrid-FPGA and its embedded PowerPC 405 processor. We explore different hardware and software optimizations and architectural configurations of the hybrid-FPGA system to demonstrate optimal performance in onboard data processing. By including a dedicated floating-point unit and dot-product co-processor in the hardware as well as utilizing optimized single-precision math library functions and a modified IBM PowerPC performance library in the software, we demonstrate a more than 8x reduction in execution time compared to the non-optimized software only implementation. A dual-processor design concept as an enhancement that would further reduce the execution time is also presented. (1 2 3). C1 [Bekker, Dmitriy L.; Lukowiak, Marcin; Shaaban, Muhammad] Rochester Inst Technol, Dept Comp Engn, 83 Lomb Mem Dr, Rochester, NY 14623 USA. [Blavier, Jean-Francois L.; Pingree, Paula J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bekker, DL (reprint author), Rochester Inst Technol, Dept Comp Engn, 83 Lomb Mem Dr, Rochester, NY 14623 USA. EM dbekker@alum.rit.edu; mxleec@rit.edu; meseec@rit.edu; Jean-Francois.Blavier@jpl.nasa.gov; Paula.J.Pingree@jpl.nasa.gov NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1641 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201018 ER PT S AU Carswell, JR Heymsfield, G Li, L Schaubert, D Creticos, J AF Carswell, James R. Heymsfield, Gerald Li, Lihua Schaubert, Dan Creticos, Justin GP IEEE TI A high altitude airborne wind mapping radar SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB (1)Through the NASA Instrument Incubator Program (IIP), NASA, the University of Massachusetts and Remote Sensing Solutions have teamed to design and develop a dual wavelength, dual beam conically scanning Doppler radar for deployment on the NASA Global Hawk platform and other high altitude aircraft. This system is to map the tropospheric, atmospheric, and surface wind fields in and around tropical cyclones by using cloud particles and precipitation as tracers. The design has been completed and the instrument is now being fabricated. To realize this system, innovations in antenna design, transmitter design and measurement processing were required. This paper shall present these innovations and outline the expected performance of this novel system. C1 [Carswell, James R.] Remote Sensing Solut, Barnstable, MA USA. [Heymsfield, Gerald] Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Li, Lihua] Univ Maryland Baltimore, Baltimore, MD USA. [Schaubert, Dan; Creticos, Justin] Univ Mass, Amherst, MA 01003 USA. RP Carswell, JR (reprint author), Remote Sensing Solut, Barnstable, MA USA. EM carswell@remotesensingsolutions.com NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1656 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201019 ER PT S AU Tanner, AB Gaier, TC Lambrigtsen, BH AF Tanner, A. B. Gaier, T. C. Lambrigtsen, B. H. GP IEEE TI GeoSTAR performance demonstration SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Ground based tests of the GeoSTAR (geostationary synthetic thinned array radiometer) demonstrator instrument are reported which simulate the view of the earth from geosynchronous earth orbit (GEO). The test used a 4-meter target disk mounted on a tower above the instrument to simulate the brightness of the earth with a contrasting cold background. Continuous observations at 50.3 GHz for over 100 hours, along with simultaneous atmospheric measurements from independent radiometers, yielded an excellent data set with which to test all aspects of the GeoSTAR calibration. This paper presents a preliminary look at these data, and presents an algorithm to remove the aliased background from the synthesized image. (1 2). C1 [Tanner, A. B.; Gaier, T. C.; Lambrigtsen, B. H.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanner, AB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1663 EP 1668 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201020 ER PT S AU Pingree, P Janssen, M Oswald, J Brown, S Chen, J Hurst, K Kitiyakara, A Maiwald, F Smith, S AF Pingree, P. Janssen, M. Oswald, J. Brown, S. Chen, J. Hurst, K. Kitiyakara, A. Maiwald, F. Smith, S. GP IEEE TI Microwave radiometers from 0.6 to 22 GHz for Juno, a polar orbiter around Jupiter SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB A compact instrument called the MWR (MicroWave Radiometer) is under development at JPL for Juno, the next NASA New Frontiers mission, scheduled to launch in 2011. It's purpose is to measure the thermal emission from Jupiter's atmosphere at six selected frequencies from 0.6 to 22 GHz, operating in direct detection mode, in order to quantify the distributions and abundances of water and ammonia in Jupiter's atmosphere. The goal is to understand the previously unobserved dynamics of the sub-cloud atmosphere, and to discriminate among models for planetary formation in our solar system. As part of a deep space mission aboard a solar-powered spacecraft, MWR is designed to be compact, lightweight, and low power. The receivers and control electronics are protected by a radiation-shielding enclosure on the Juno spacecraft that also provides for a benign and stable operating temperature environment. All antennas and RF transmission lines outside the vault must withstand low temperatures and the harsh radiation environment surrounding Jupiter. This paper describes the concept of the MWR instrument and presents results of one breadboard receiver channel. (1,2). C1 [Pingree, P.; Janssen, M.; Oswald, J.; Brown, S.; Chen, J.; Hurst, K.; Kitiyakara, A.; Maiwald, F.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Smith, S.] MMW Technol Inc, Lawndale, CA 90260 USA. RP Pingree, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Paula.J.Pingree@jpl.nasa.gov; Michael.A.Janssen@jpl.nasa.gov; John.E.Oswald@jpl.nasa.gov; Shannon.T.Brown@jpl.nasa.gov; Jacqueline.C.Chen@jpl.nasa.gov; Kenneth.J.Hurst@jpl.nasa.gov; Amarit.Kitiyakara@jpl.nasa.gov; Frank.W.Maiwald@jpl.nasa.gov; Steve@mmwtechnology.com NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1669 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201021 ER PT S AU Chamberlain, N Sadowy, G AF Chamberlain, Neil Sadowy, Gregory GP IEEE TI The UAVSAR transmit/receive module SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper describes the L-band transmit/receive (T/R) modules of the UAVSAR phased array antenna. UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) is an airborne, repeat-pass, polarimetric radar interferometer instrument that is being developed at JPL and NASA Dryden. The instrument has demanding requirements for phase stability over temperature and the antenna components, particularly the T/R modules, are key to meeting these requirements. The UAVSAR T/R modules have a bandwidth of more than 80 MHz centered at 1257.5 MHz and support dual receivers for full quad polarization measurements. Phase and amplitude are controlled by a 7-bit phase shifter and a 5-bit attenuator, respectively. Custom microwave integrated circuits were developed and fabricated for the low noise amplifier (LNA) and phase shifter circuits. The receiver noise figure is 2.25 dB at 0C including all front-end losses. The transmitter power amplifiers use silicon bipolar junction transistors that typically generate 162 W peak into a nominal 50 ohm load. The modules have an overall efficiency of 32% at the peak operating duty cycle of 5%. Module mass and dimensions are 567g and 16 cm x 12 cm x 3 cm, respectively. Fifty four of these T/R modules were fabricated for integration into two antennas. System architecture and performance data for this ensemble of modules are discussed.(1,2). C1 [Chamberlain, Neil; Sadowy, Gregory] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chamberlain, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1684 EP 1698 PG 15 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201022 ER PT S AU Kangaslahti, P Deal, WR Mei, XB Lai, R AF Kangaslahti, P. Deal, W. R. Mei, X. B. Lai, R. GP IEEE TI Broadband characterization of a 100 to 180 GHz amplifier SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE DE high electron mobility transistors (HEMTs); indium phosphide; millimeter wave field-effect transistor (FET) amplifiers; monolithic millimeter wave integ low noise amplifier; MMIC ID MMIC AMPLIFIER AB Atmospheric science and weather forecasting require measurements of the temperature and humidity vs. altitude. These sounding measurements are obtained at frequencies close to the resonance frequencies of oxygen (118 GHz) and water (183 GHz) molecules. We have characterized a broadband amplifier that will increase the sensitivity of sounding and other instruments at these frequencies. This study demonstrated for the first time continuous low noise amplification from 100 to 180 GHz. The measured InP monolithic millimeter-wave integrated circuit (MMIC) amplifier had more than 18 dB of gain from 100 to 180 GHz and 15 dB of gain up to 220 GHz. This is the widest bandwidth low noise amplifier result at these frequencies to date. The circuit was fabricated in Northrop Grumman Corporation 35 nm InP high electron mobility transistor (HEMT) process. C1 [Kangaslahti, P.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Deal, W. R.; Mei, X. B.; Lai, R.] Northrop Grumman Corp, Redondo Beach, CA 90278 USA. RP Kangaslahti, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Pekka.Kangaslahti@jpl.nasa.gov FU NASA ESTO Advanced Component Technologies [ACT-05]; DARPA SWIFT Program and Army Research Laboratory under the DARPA MIPR [06-U037]; ARL [W91 IQX-06-C-0050] FX This work was supported by the by the NASA ESTO Advanced Component Technologies ACT-05 program and DARPA SWIFT Program and Army Research Laboratory under the DARPA MIPR no.06-U037 and ARL Contract no. W91 IQX-06-C-0050. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1699 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201023 ER PT S AU Wallace, JK Bartos, R Best, P Levine, BM Nemati, B Shao, M Shelton, C AF Wallace, J. Kent Bartos, Randall Best, Paul Levine, B. Martin Nemati, Bijan Shao, Mike Shelton, Chris GP IEEE TI Preliminary results from an interferometric post-coronagraph wave front sensor SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In high contrast imaging system, semi-static, non-common path wave front errors not sensed by the active wave front sensor in an adaptive optics system win 'leak' around the coronagraph and lead to focal plane speckles that will mask exo-planets. Sensing and controlling these speckles is an absolute necessity for direct detection of planets from the ground. The next generation of AO systems that will enable direct detection of planets from the ground will become operational in the next couple of years. One of them, the Gemini Planet Imager, or GPI, win incorporate an interferometric wave front sensor, designed and developed at JPL, which will measure these errors. This talk will emphasis this novel sensor and describes how it is used to measure the non-common path amplitude and phase errors in the system that would otherwise limit the achievable contrast. We will describe the system error budget as well as simulations that model the system performance. The current status of the GPI Calibration System will be detailed, along with initial wavefront measurement results. This system promises a rich combination of interferometry and large optical systems in support of cutting edge science research. C1 [Wallace, J. Kent; Bartos, Randall; Best, Paul; Levine, B. Martin; Nemati, Bijan; Shao, Mike; Shelton, Chris] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wallace, JK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1723 EP 1728 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201026 ER PT S AU Goullioud, R Catanzarite, JH AF Goullioud, R. Catanzarite, J. H. GP IEEE TI Looking for earth-like planets with the SIM planet quest light mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Space Interferometry Mission Planet Quest Light (SIM PQL) is a new concept for a space borne astrometric instrument. It will be located in a solar Earth-trailing orbit. SIM PQL utilized technology developed for the Space Interferometry Mission Planet Quest (SIM PQ). The instrument consists of two Michelson stellar interferometers and a telescope. The first interferometer chops between the target star and a set of reference stars. The second interferometer monitors the attitude of the instrument in the direction of the target star. The telescope monitors the attitude of the instrument in the other two directions. C1 [Goullioud, R.; Catanzarite, J. H.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Goullioud, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 171-113, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1729 EP 1737 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201027 ER PT S AU Martin, S Scharf, DP Wirz, R Lay, O McKinstry, D Mennesson, B Purcell, G Rodriguez, J Scherr, L Smith, JR Wayne, L AF Martin, Stefan Scharf, Daniel P. Wirz, Richard Lay, Oliver McKinstry, David Mennesson, Bertrand Purcell, George Rodriguez, Jose Scherr, Laurence Smith, James R. Wayne, Leonard GP IEEE TI Design study for a planet-finding space iterferometer SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The characterization of earthlike planets that may be orbiting nearby stars will require large observatories capable of detecting a small number of planet photons and separating them from the much larger flux from the parent star. One approach to this is to employ nulling interferometry on a space-based platform utilizing a number of spacecraft. At the Jet Propulsion Laboratory, a linear dual chopped Bracewell array design was studied in depth while in Europe various two-dimensional designs were discussed. This study looks in a little more depth at the design issues for one of the European concepts and concludes that the concept has promise for a significant reduction in spacecraft complexity and mass and therefore would result in a lower cost mission". C1 [Martin, Stefan; Scharf, Daniel P.; Wirz, Richard; Lay, Oliver; McKinstry, David; Mennesson, Bertrand; Purcell, George; Rodriguez, Jose; Scherr, Laurence; Smith, James R.; Wayne, Leonard] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Martin, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1738 EP 1756 PG 19 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201028 ER PT S AU Memarsadeghi, N Raykar, VC Duraiswami, R Mount, DM AF Memarsadeghi, Nargess Raykar, Vikas C. Duraiswami, Ramani Mount, David M. GP IEEE TI Efficient kriging via fast matrix-vector products SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE DE geostatistics; image fusion; kriging; approximate algorithms; fast multipole methods; fast Gauss transform; nearest neighbors; iterative methods ID IMAGE FUSION; INTERPOLATION; COVARIANCE; SYSTEMS AB Interpolating scattered data points is a problem of wide ranging interest. Ordinary kriging is an optimal scattered data estimator, widely used in geosciences and remote sensing. A generalized version of this technique, called cokriging, can be used for image fusion of remotely sensed data. However, it is computationally very expensive for large data sets. We demonstrate the time efficiency and accuracy of approximating ordinary kriging through the use of fast matrixvector products combined with iterative methods. We used methods based on the fast Multipole methods and nearest neighbor searching techniques for implementations of the fast matrix-vector products. C1 [Memarsadeghi, Nargess] NASA, Goddard Space Flight Ctr, Code 587, Greenbelt, MD 20771 USA. [Raykar, Vikas C.] Siemens Medical Solut, Malvern, PA USA. [Duraiswami, Ramani; Mount, David M.] Univ Maryland, College Pk 20742, MD USA. RP Memarsadeghi, N (reprint author), NASA, Goddard Space Flight Ctr, Code 587, Greenbelt, MD 20771 USA. EM Nargess.Memarsadeghi@nasa.gov; vikas.raykar@siemens.com; ramani@cs.umd.edu; mount@cs.umd.edu FU National Science Foundation [CCR-0635099] FX The work of D.M. Mount has been supported in part by the National Science Foundation under grant CCR-0635099. NR 29 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 1966 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201051 ER PT S AU Woo, S Jennings, E Clare, L AF Woo, Simon Jennings, Esther Clare, Loren GP IEEE TI A simulation tool for ASCTA microsensor network architecture SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Advances in technology have made the large-scale deployment of low-cost networked sensors possible for situational awareness. We developed a Simulation Tool for the Advanced Sensors Collaborative Technology Alliance (ASCTA) Microsensor Network Architecture (STAMiNA) to evaluate the performance of networked sensor systems. This tool is built upon a commercial network simulator engine (QualNet), with extended capabilities to include both sensing and communication models in a discrete-event simulation environment. Using this tool, we can simulate target detection (sensing) and information dissemination (information fusion) via wireless communications under different parameters and scenarios, incorporating such metrics as target detection probabilities, false alarm rates, and communications load, and capturing effects of terrain and threat characteristics. An example of tool usage is presented illustrating the comparison of alternative microsensor network architectures such as localized-fusion, hierarchical-fusion, and distributed-fusion in the presence of false detection events. The trade-offs among these three different sensor architectures are examined under different fusion rules, sensing sliding window sizes, and false-event occurrence rates. Operating parameters that yield high detection and low false-alarm performance are examined. C1 [Woo, Simon; Jennings, Esther; Clare, Loren] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Woo, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2115 EP 2123 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201065 ER PT S AU Hilliard, L AF Hilliard, L. GP IEEE TI Development of coherent, Expandable, Reconfigurable Instrument Node (ERIN) for web sensor applications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Microwave radars operating over the L-band microwave spectrum are often used as sensors for estimation of vegetation biomass, land surface topography and surface deformation, surface soil moisture, and polar ice sheets thickness. Monitoring of these parameters is essential for gauging the Earth's ecosystem. Because of restriction on the mass and size of a radar sensor that can be deployed on a small aircraft/spacecraft, the surface resolution with which these essential earth parameters can be improved using this technology by forming interferometric baselines between nodes. The Expandable Reconfigurable Instrument Node (ERIN) will provide a semi-closed loop system solution for a variety of sensors. The ERIN baselines a reconfigurable processing technology with required memory to allow on-board processing of science data. Standardized interfaces are provided to allow for interfacing to attitude control instrumentation such as Global Positioning Systems (GPS) and Inertial Measurement Units (IMU). A communications device will be added to the node that would allow for node-to-node communications.(12). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hilliard, L (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2134 EP 2141 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201067 ER PT S AU Morris, R Dungan, J Votava, P Khatib, L AF Morris, Robert Dungan, Jennifer Votava, Petr Khatib, Lina GP IEEE TI Coordinated data acquisition on sensor webs SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper focuses on the application of automated planning, scheduling, and plan execution to Earth science campaigns, an organized sequence of observations and data analysis activities associated with an Earth science objective. We propose a layered architecture for coordinating sensing assets, and describe a process for automatically transforming science goals (such as monitoring a volcano or other Earth process) into sequences of data acquisitions. C1 [Morris, Robert; Dungan, Jennifer; Votava, Petr; Khatib, Lina] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Morris, R (reprint author), NASA, Ames Res Ctr, MS 269-1, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2142 EP 2148 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201068 ER PT S AU Burl, MC Garay, NJ Wang, Y Ng, J AF Burl, Michael C. Garay, Nfichael J. Wang, Yi Ng, Justin GP IEEE TI Adaptive Sky: A feature correspondence toolbox for a multi-instrument, multi-platform distributed cloud monitoring sensor web SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SYSTEM AB The current suite of spaceborne and in-situ assets, including those deployed by NASA, NOAA, and other groups, provides distributed sensing of the Earth's atmosphere, oceans, and land masses. As part of an activity supported through NASA's Earth Science Technology Office (ESTO), we have developed techniques that enable such assets to be dynamically combined to form sensor webs that can respond quickly to short-lived events and provide rich multi-modal observations of objects, such as clouds, that are evolving in space and time. A key focus of this work involves relating the observations made by one instrument to the observations made by another instrument. We have applied approaches derived from data mining, computer vision, and machine learning to automatically establish correspondence between different sets of observations. We will describe a number of Earth science scenarios that were used to direct this development and which have benefited from the approach.(12). C1 [Burl, Michael C.; Garay, Nfichael J.; Wang, Yi; Ng, Justin] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Burl, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2149 EP 2156 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201069 ER PT S AU Tian, YD Houser, PR Su, HB Kumar, SV Geiger, JV AF Tian, Yudong Houser, Paul R. Su, Hongbo Kumar, Sujay V. Geiger, James V., Jr. GP IEEE TI Integrating sensor webs with modeling and data-assimilation applications: An SOA implementation SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SYSTEM; FRAMEWORK AB A sensor web framework is implemented to enable two-way interactions between sensors and traditional modeling/data-assimilation applications for the Land Information Sensor Web (LISW). A service-oriented architecture (SOA) is adopted and implemented with REpresentational State Transfer (REST)-style web services. The web services are built upon a message-oriented middleware with a publish/subscribe model. Prototype sensor observation service (SOS) and sensor planning service (SPS) are implemented as REST-style web services. These services are provided by a sensor simulator. Such an open, interoperable and dynamic framework greatly simplifies the integration of sensing agents and modeling applications. It also enables development of feature-rich web applications which can tap into LISW's web services for data visualization and decision making. As an example, we demonstrate an interactive web application with Asynchronous JavaScript and XML (AJAX) technology, its integration with Google Map, and its two-way interaction with the sensor simulator which simulates 60 temperature sensors over the U.S.(1) (2). C1 [Tian, Yudong; Kumar, Sujay V.; Geiger, James V., Jr.] NASA, Goddard Space Flight Ctr, Code 614-3, Greenbelt, MD 20771 USA. [Houser, Paul R.; Su, Hongbo] IGES, Ctr Res Environ & Water, Beltsville, MD 20705 USA. RP Tian, YD (reprint author), NASA, Goddard Space Flight Ctr, Code 614-3, Greenbelt, MD 20771 USA. EM Yudong.Tian@nasa.gov RI Houser, Paul/J-9515-2013; Kumar, Sujay/B-8142-2015 OI Houser, Paul/0000-0002-2991-0441; NR 8 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2157 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201070 ER PT S AU Donnellan, A Parker, J Granat, R Fox, G Pierce, M Rundle, J McLeod, D Al-Ghanmi, R Grant, L Brooks, W AF Donnellan, Andrea Parker, Jay Granat, Robert Fox, Geoffrey Pierce, Marlon Rundle, John McLeod, Dennis Al-Ghanmi, Rami Grant, Lisa Brooks, Walter GP IEEE TI QuakeSim: Efficient modeling of sensor web data in a web services environment SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID THRESHOLD SYSTEMS; EARTHQUAKES; DYNAMICS AB QuakeSim is a project to develop a modeling environment for studying earthquake processes using a web services environment. In order to model interseismic processes multiple data types must be ingested including spaceborne GPS and InSAR data, geological fault data, and seismicity data. QuakeSim federates data from these multiple sources and integrates the databases with modeling applications. Because the models are complex and compute intensive we are using the Columbia computer located at NASA Ames to integrate and run software programs to improve our understanding of the solid Earth and earthquake processes. The complementary software programs are used to simulate interacting earthquake fault systems, model nucleation and slip on faults, and calculate run-up and inundation from tsunamis generated by offshore earthquakes. QuakeSim also applies pattern recognition techniques to real and simulated data to elucidate subtle features in the processes.(1 2). C1 [Donnellan, Andrea; Parker, Jay; Granat, Robert] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Fox, Geoffrey; Pierce, Marlon] Indiana Univ, Community Grids Lab, Bloomington, IL USA. [Rundle, John] Univ Calif Davis, Dept Phys, Davis, CA USA. [McLeod, Dennis; Al-Ghanmi, Rami] Univ Southern Calif, Los Angeles, CA 90089 USA. [Grant, Lisa] Univ Calif Irvine, Irvine, CA 92697 USA. RP Donnellan, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrea.Donnellan@jpl.nasa.gov NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2164 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201071 ER PT S AU Davies, AG Castano, R Chien, S Tran, D Mandrake, L Wright, R Kyle, P Komorowski, JC Mandl, D Noblis, SF AF Davies, Ashley Gerard Castano, Rebecca Chien, Steve Tran, Daniel Mandrake, Lukas Wright, Robert Kyle, Philip Komorowski, Jean-Christophe Mandl, Dan Noblis, Stuart Frye GP IEEE TI Rapid response to volcanic eruptions with an autonomous sensor web: The Nyamulagira eruption of 2006 SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Rapid response to alerts of impending or active volcanism is vital in the assessment of volcanic risk and hazard. The JPL Model-Driven Volcano Sensor Web (MSW) demonstrated such an autonomous response during a volcanic crisis at Nyamulagira. volcano, D. R. Congo, in December 2006, quickly providing vital information to volcanologists in the field. The MSW was developed to enable fast science-driven asset command and control. Alerts of volcanic activity from around the world are used to trigger high resolution observations (both spectral and spatial) by the EO-1 spacecraft. Data are processed onboard EO-1 by advanced software (the Autonomous Sciencecraft Experiment [ASE]). If volcanic thermal emission is detected, ASE retasks EO-1 to obtain more data. A summary of the observation is returned within two hours of data acquisition. T-12. C1 [Davies, Ashley Gerard; Castano, Rebecca; Chien, Steve; Tran, Daniel; Mandrake, Lukas] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Wright, Robert] Univ Hawai Manoa, Inst Geophys & Planetol, Honolulu, HI 96822 USA. [Kyle, Philip] New Mexico Inst Min & Technol, Dept Earth & Environm Sci, Socorro, NM 87801 USA. [Komorowski, Jean-Christophe] CNRS, Inst Physique Globe Paris, UMR 7154, Dept Geol Systemes Volcaniques, F-75252 Paris, France. [Mandl, Dan] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Davies, AG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ashley.Davies@jpl.nasa.gov; wright@higp.hawaii.edu; kyle@nmt.edu; komorow@ipgp.jussieu.fr; dan.mandl@gsfc.nasa.gov; Stuart.Frye@gsfc.nasa.gov FU NASA Advanced Information Science Technology (AIST) Program FX This work was carried out at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA. We gratefully acknowledge funding from the NASA Advanced Information Science Technology (AIST) Program. We acknowledge the contributions to this work of Paolo Papale and colleagues at L'Istituto Nazionale di Geofisica e Vulcanologia (INGV) and of Kasereka Mahinda and colleagues at the Goma Volcano Observatory (GVO-CRSN). EO-1 is managed by the NASA Goddard Space Flight Center. With a task of this magnitude, many persons are involved. We especially thank Chris Stevens, NMP Program Manager at JPL, Simon Hook, the NMP Program Scientist (Earth) at JPL, Art Chmielewski, NMP ST-6 Project Manager, Rob Sherwood, ASE Project Manager and JPL AIST Program Manager; and the staff, faculty and students of the Mount Erebus Volcano Observatory, New Mexico Institute of Mining and Technology. NR 15 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2190 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201074 ER PT S AU Moe, K Smith, S Prescott, G Sherwood, R AF Moe, Karen Smith, Steve Prescott, Glenn Sherwood, Rob GP IEEE TI Sensor web technologies for NASA earth science SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Recent technological advancements in microelectronics, wireless communications, intelligent systems and networking have led to the conceptualized notion of a "web" of sensors, interconnected and interacting with one another to provide observations and measurements of geophysical phenomena, and routing data (or information) directly to researchers, scientists and other destinations (including forecast models and data archives). This is the concept that we call the "sensor web." A vision for NASA sensor webs for Earth science is to enable "on-demand sensing of a broad array of environmental and ecological phenomena across a wide range of spatial and temporal scales, from a heterogeneous suite of sensors both in situ and in orbit." This paper takes a high level. view of sensor webs, describing their characteristics and giving examples of how NASA sees these systems contributing to our knowledge of the world in which we live. Examples of sensor web prototypes and research highlights will be presented from some of the research projects recently funded by the NASA Earth Science Technology Office and currently underway in universities, industries and NASA research centers throughout the country. The paper concludes by imagining how sensor webs will be used in the future and describing the key research technologies that will be needed to fully realize this vision. C1 [Moe, Karen; Smith, Steve; Prescott, Glenn] NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA. [Sherwood, Rob] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Moe, K (reprint author), NASA, Goddard Space Flight Ctr, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA. EM Karen.Moe@nasa.gov; Steven.A.Smith@nasa.gov; Glenn.E.Prescott@nasa.gov; Rob.Sherwood@jpl.nasa.gov NR 8 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2211 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201076 ER PT S AU Talukder, A Panangadan, A Herrington, T Blumberg, A Georgias, N AF Talukder, Ashit Panangadan, Anand Herrington, Thomas Blumberg, Alan Georgias, Nickitas GP IEEE TI Autonomous adaptive resource management in sensor network systems for environmental monitoring SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID MODEL-PREDICTIVE CONTROL; OPTIMIZATION AB The paper describes the use of model predictive control (MPC) as a framework for optimal resource management in environmental monitoring sensor networks. The WC formulation adapts sensor and network parameters (such as sensor sampling rates, and routing of data) that impact the utilization of the system resources (such as energy reserves at off-shore in-situ sensors, and wireless bandwidth). The control parameters are optimized so as to maximize a measure of the total information extracted from the system. This information measure takes into account the spatio-temporal events of interests that are detected in the environment. The approach is illustrated on a coastal monitoring and forecast system that is in operation in the New York harbor and surrounding area. Offline results using actual modeled data from in-situ sensory measurements demonstrate how the sensor parameters can be adapted to maximize observability of a freshwater plume while ensuring that individual system components operate within their physical limitations. (c) 2008 IEEE. C1 [Talukder, Ashit] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Panangadan, Anand] CHLA USC, Los Angeles, CA 90027 USA. [Herrington, Thomas; Blumberg, Alan; Georgias, Nickitas] Stevens Inst Technol, Hoboken, NJ USA. RP Talukder, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ashit.Talukder@jpl.nasa.gov; APanangadan@chla.usc.edu FU NASA Applied Information Systems Technology Program under AISTQRS [AIST-QRS-06-0017] FX This work has been sponsored by the NASA Applied Information Systems Technology Program under AISTQRS Award # AIST-QRS-06-0017. NR 35 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2218 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201077 ER PT S AU Elfes, A Podnar, GW Dolan, JM Stancliff, S Lin, E Hosler, JC Ames, TJ Higinbotham, J Moisan, JR Moisan, TA Kulczycki, EA AF Elfes, Alberto Podnar, Gregg W. Dolan, John M. Stancliff, Stephen Lin, Ellie Hosler, Jeffrey C. Ames, Troy J. Higinbotham, John Moisan, John R. Moisan, Tiffany A. Kulczycki, Eric A. GP IEEE TI The telesupervised adaptive ocean sensor fleet architecture SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Earth science research must bridge the gap between the atmosphere and the ocean to foster understanding of Earth's climate and ecology. Ocean sensing is typically done with satellites, buoys, and crewed research ships. The limitations of these systems include the fact that satellites are often blocked by cloud cover, and buoys and ships have spatial coverage limitations. This paper describes a Multilevel Autonomy. Robot Telesupervision Architecture (MARTA) for multi-robot science exploration, and an embodiment of the MARTA architecture in a real-world system called the Telesupervised Adaptive Ocean Sensor Fleet (TAOSF). TAOSF supervises and coordinates a group of robotic boats, the OASIS platforms, to enable in-situ study of phenomena in the ocean/atmosphere interface, as well as on the ocean surface and sub-surface. The OASIS platforms are extended-deployment autonomous ocean surface vehicles, whose development is funded separately by the National Oceanic and Atmospheric Administration (NOAA). TAOSF allows a human operator to effectively supervise and coordinate multiple robotic assets using the MARTA multi-level autonomy control architecture, where the operating mode of the vessels ranges from autonomous control to teleoperated human control. TAOSF increases data-gathering effectiveness and science return while reducing demands on scientists for robotic asset tasking, control, and monitoring. The first field application chosen for TAOSF is the characterization of Harmful Algal Blooms (HABs). We discuss the overall TAOSF system and the underlying MARTA architecture, describe field tests conducted under controlled conditions using rhodamine dye as a HAB simulant, present initial results from these tests, and outline the next steps in the development of TAOSF. C1 [Elfes, Alberto; Kulczycki, Eric A.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Podnar, Gregg W.; Dolan, John M.; Stancliff, Stephen; Lin, Ellie] Carnegie Mellon Univ, Inst Robot, Pittsburgh, PA 15213 USA. [Ames, Troy J.] NASA, Goddard Space Flight Fac, Code 916, Greenbelt, MD 20771 USA. [Higinbotham, John] Emergent Space Technol, Greenbelt, MD 20770 USA. [Ames, Troy J.; Moisan, John R.; Moisan, Tiffany A.] NASA, Wallops Flight Facility, Wallops Isl, VA 23337 USA. RP Elfes, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM elfes@jpl.nasa.gov; gwp@cs.cmu.edu; jmd@cs.cmu.edu; stancliff@cmu.edu; elliel@andrew.cmu.edu; jeffrey.c.hosler@nasa.gov; troy.j.ames@nasa.gov; john.higinbotham@emergentspace.com; John.R.Moisan@nasa.gov; tmoisan@osb1.wff.nasa.gov; eric.a.kulczycki@jpl.nasa.gov RI Elfes, Alberto/E-2463-2011; Moisan, John/B-8762-2016 OI Elfes, Alberto/0000-0003-2433-995X; Moisan, John/0000-0002-8078-8939 FU NASA [NNX06AF27G]; National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce [NA03NOS4730220] FX This work was supported by NASA award NNX06AF27G, Telesupervised Adaptive Ocean Sensor Fleet, granted under the Advanced Information Systems Technology program of NASAs Earth Systems Technology Office (ESTO). The TAOSF project is a collaboration among Carnegie Mellon University (CMU), NASA Goddard Space Flight Center (GSFC), NASA Goddards Wallops Flight Facility (WFF), Emergent Space Technologies, Inc. (EST), and the Jet Propulsion Laboratory (JPL), California Institute of Technology. Work on the OASIS platforms is conducted by Emergent Space Technologies, Inc., EG&G, and Zinger Enterprises under award NA03NOS4730220 from the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2227 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201078 ER PT S AU Patrick, MC AF Patrick, M. Clinton GP IEEE TI Reconfigurable computing concepts for space missions: Universal modular spares SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Computer hardware systems for control, data collection and other purposes will once more be crucial resources in NASA's upcoming space missions. Compulsion to provide these resources within mission payload requirements, with hardiness to operate for extended periods under potentially harsh conditions in off-World environments, is daunting enough without considering the possibility of doing so with conventional electronics. This paper examines some ideas and options, and proposes some initial approaches, for design of reconfigurable computing resources offering true modularity, universal compatibility, and unprecedented flexibility to service all forms and needs of mission infrastructure. C1 NASA MSFC EV43, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Patrick, MC (reprint author), NASA MSFC EV43, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2279 EP 2286 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201084 ER PT S AU Shahabuddin, M Murray, A Carson, V AF Shahabuddin, Mohammad Murray, Alexander Carson, Vanessa GP IEEE TI Component-based, run-time flight software modification SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Missions involving robotic space flight typically have a way to change the software that controls the flight system, or some part of it, such as an instrument, after launch. Usually this is accomplished by uplinking small sets of binary machine instructions and writing them to known locations in memory. We-present an approach, used on the Aquarius mission, that involves replacing running components of, or adding components to, the running software at a higher logical level, specifically at the software architecture level, and on the C++ rather than machine-language level. This approach provides significant advantages in flexibility, robustness, reliability, and testability. We present the component-based flight software (FSW) design features that enable these capabilities. We then discuss the approach used to verify the robustness and reliability of these techniques, and finally describe usages to date. C1 [Shahabuddin, Mohammad; Murray, Alexander; Carson, Vanessa] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shahabuddin, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2287 EP 2302 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201085 ER PT S AU Stoica, A Keymeulen, D Mojarradi, M Zebulum, R Daud, T AF Stoica, Adrian Keymeulen, Didier Mojarradi, Mohammad Zebulum, Ricardo Daud, Taher GP IEEE TI Progress in the development of field programmable analog arrays for space applications SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID EVOLVABLE HARDWARE AB Development of analog electronic solutions for space avionics is expensive and lengthy. Lack of flexible analog devices, counterparts to digital Field Programmable Gate Arrays (FPGA), prevents analog designers from benefits of rapid prototyping. This forces them to expensive and lengthy custom design, fabrication, and qualification of application specific integrated circuits (ASIC). The limitations come from two directions: first, commercial Field Programmable Analog Arrays (FPAA) have very limited variability in the components offered on-chip (practically one type of operational amplifiers/ comparator per chip); and second, these are only qualified for best case scenarios for military grade (-55 degrees C to +125 degrees C). However, analog circuitry required for sensing and control involves a larger variability. Moreover, in order to avoid huge overheads in mass, energy and wiring, there is a growing trend towards avoiding thermal and radiation protection by developing extreme environment electronics. This means electronics that maintain correct operation while exposed to temperature extremes e.g., on Moon (-180 degrees C to +125 degrees C). This paper describes a recent FPAA design, the Self Reconfigurable Analog Array (SRAA) that was developed at JPL. It overcomes both limitations, offering a variety of analog cells inside the array together with the possibility of self-correction at extreme temperatures. C1 [Stoica, Adrian; Keymeulen, Didier; Mojarradi, Mohammad; Zebulum, Ricardo; Daud, Taher] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stoica, A (reprint author), CALTECH, Jet Prop Lab, MS 303-300,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2360 EP 2368 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201092 ER PT S AU Gontijo, I AF Gontijo, Ivair GP IEEE TI High speed RF packaging design and fabrication for Ka-band radar systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The various choices of materials for RF packaging are reviewed and two groups of materials are used to package components for a Ka-band landing radar. A Kovar housing was designed and built for a Transmit/Receive module, which provides good RF performance and allows the high power semiconductor amplifiers to be mounted directly to pedestals at the bottom of the package. For the Up/Down converter, an Aluminum housing was designed and built with all connectors laser welded in place. Both packages are hermetic and capable of withstanding a differential pressure of over 30 psi. Environmental requirements are taken into consideration during package design, such as thermal cycling, absolute maximum temperature ratings of components and structural aspects. Details of the electrical package design to minimize radiation loss and cross talk are discussed, as well as various methods of attachment of the RF connectors to the housings. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gontijo, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2389 EP 2394 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201095 ER PT S AU Schatzel, DV AF Schatzel, Donald V. GP IEEE TI Flip chip reliability on dynamically loaded multi-functional spacecraft structures SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Electronic packages for space flight are becoming increasingly dense to allow for increased processing power and functionality. This has resulted in further hybridization of electronics where active devices are no longer surrounded by there own case or component package and are directly attached to the substrate. Chip-On-Board approaches are being qualified for space flight use with Flip Chip approaches required to meet smaller volume requirements. These bare die attachment solutions are resulting in electronic sub-systems that have significantly lower weight and volume than state-of-the-art designs. Incorporating electronic traces or signal paths directly into the spacecraft or instrument structure can provide a significant savings in weight and volume. In addition, local computer processing power, increased operational speed and larger memory storage are achievable by using embedded or direct chip attach design methods. Recent developments in printed circuit board fabrication processes has given printed circuit boards increased strength and stiffness by incorporating single or multiple carbon graphite weave layers within the printed circuit board structure during the lamination fabrication process. Previous technology development work has demonstrated the significant mechanical yield strength and stiffness of multifunctional structures when printed circuit boards are laminated with graphite weave made from carbon fiber strands. Standard printed circuit board planar geometries with unique design features are used to construct three dimensional structural elements comprising a subsystem multi-functional structure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schatzel, DV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2395 EP 2400 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201096 ER PT S AU Tudryn, CD AF Tudryn, Carissa D. GP IEEE TI Survivability of flip chips using PCBs with carbon fiber in a fatigue environment SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Flip Chip packaging technology is being developed using printed circuit boards (PCBs) with carbon fiber composites or STABLCOR (R), to withstand low temperature, fatigue conditions on Mars, from -130 degrees C to +85 degrees C, for a 1 year mission. This technology will benefit future rovers by allowing for electronic packaging to be incorporated as highly dense, low mass multifunctional structures outside a warm electronics box (WEB). STABLCOR (R) is fabricated within the PCB in proximity to the flip chips. The flip chips on. boards with and without carbon fiber weave failed due to thermal strain and, ultimately, fatigue. It was also found that the carbon fiber weave within the board affects the flatness and, ultimately, the survivability of flip chips. Further experiments must be performed in order to fully determine if STABCLOR (R) increases the flip chip survivability in this extreme environment. This paper describes the design, assembly, and testing of flip chips in this extreme environment, and additional experiments needed for the flip chip packaging on boards with and without STABLCOR (R). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tudryn, CD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2401 EP 2406 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201097 ER PT S AU Rice, EB Lev-Tov, SJ AF Rice, Eric B. Lev-Tov, Sean J. GP IEEE TI Optimized spacecraft fault protection for the WISE mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The WISE project is a NASA-funded medium-class Explorer mission to map the entire sky in four infrared bands during the course of a 6-month survey. Because of the mission's limited financial resources, a traditional robustness strategy of full block-redundancy was not feasible. By leveraging aspects of the mission design that tend to reduce the risk associated with certain failures, the project has been able to adopt a robustness strategy of initigating high-risk failures, while accepting the risk of low-impact faults or unlikely faults in heritage equipment with proven reliability. The resulting WISE flight system design is primarily single-string with some select functional- and block-redundancy and includes fault tolerance measures targeted at achieving the most cost-effective risk reduction possible for the system design. The fault protection team has been challenged with balancing the risk of faults, cost, and down-time with Ground Segment capabilities, heritage, and effectively designed fault mitigations. Faults were identified via a collection of analyses, and a criticality rating was applied to each fault to assess its impact to the mission. Taking into consideration each fault's impact and time criticality, mitigations to each possible fault were considered in areas such as on-board autonomy, the addition or use of functional and block redundancy, and ground system detection. Through this exercise, the project has realized a robust and reliable system design in line with the project's risk posture and cost constraints. C1 [Rice, Eric B.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Lev-Tov, Sean J.] Ball Aerospace & Technol Corp, Boulder, CO 80301 USA. RP Rice, EB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Eric.Rice@jpl.nasa.gov; slevtov@ball.com NR 5 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2416 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201100 ER PT S AU Barltrop, KJ Friberg, KH Horvath, GA AF Barltrop, Kevin J. Friberg, Kenneth H. Horvath, Gregory A. GP IEEE TI Automated generation and assessment of autonomous systems test cases SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Verification and validation testing of autonomous spacecraft routinely culminates in the exploration of anomalous or faulted mission-like scenarios. Prioritizing which scenarios to develop usually comes down to focusing on the most vulnerable areas and ensuring the best return on investment of test time. Rules-of-thumb strategies often come into play, such as injecting applicable anomalies prior to, during, and after system state changes; or, creating cases that ensure good safety-net algorithm coverage. Although experience and judgment in test selection can lead to high levels of confidence about the majority of a system's autonomy, it's likely that important test cases are overlooked. One method to fill in potential test coverage gaps is to automatically generate and execute test cases using algorithms that ensure desirable properties about the coverage. For example, generate cases for all possible fault monitors, and across all state change boundaries. Of course, the scope of coverage is determined by the test environment capabilities, where a faster-than-real-time, high-fidelity, software-only simulation would allow the broadest coverage. Even real-time systems that can be replicated and run in parallel, and that have reliable set-up and operations features provide an excellent resource for automated testing. Making detailed predictions for the outcome of such tests can be difficult, and when algorithmic means are employed to produce hundreds or even thousands of cases, generating predicts individually is impractical, and generating predicts with tools requires executable models of the design and environment that themselves require a complete test program. Therefore, evaluating the results of large number of mission scenario tests Poses special challenges. A good approach to address this problem is to automatically score, the results based on a range of metrics. Although the specific means of scoring depends highly on the application, the use of formal scoring metrics has high value in identifying and Prioritizing anomalies, and in presenting an overall picture of the state of the test program. In this paper we present a case study based on automatic generation and assessment of faulted test runs for the Dawn mission, and discuss its role in optimizing the allocation of resources for completing the test program. C1 [Barltrop, Kevin J.; Friberg, Kenneth H.; Horvath, Gregory A.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barltrop, KJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2437 EP 2446 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201102 ER PT S AU Keymeulen, D Peay, C Foor, D Trung, T Bakhshi, A Withington, P Yee, K Terrile, R AF Keymeulen, Didier Peay, Chris Foor, David Trung, Tran Bakhshi, Alireza Withington, Phil Yee, Karl Terrile, Rich GP IEEE TI Control of MEMS Disc Resonance Gyroscope (DRG) using a FPGA platform SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Inertial navigation systems based upon optical gyroscopes tend to be expensive, large, power consumptive, and are not long lived. Micro-Electromechanical Systems (MEMS) based gyros do not have these shortcomings; however, until recently, the performance of MEMS based gyros had been below navigation grade. Boeing and JPL have been co-operating since 1997 to develop high performance MEMS gyroscopes for miniature, low power space Inertial Reference Unit applications(12). The efforts resulted in demonstration of a Post Resonator Gyroscope (PRG). This experience led to the more compact Disc Resonator Gyroscope (DRG) for further reduced size and power with potentially increased performance. Currently, the mass, volume and power of the DRG are dominated by the size of the electronics. This paper will detail the FPGA based digital electronics architecture and its implementation for the DRG which will allow reduction of size and power and will increase performance through a reduction in electronics noise. Using the digital control based on FPGA, we can program and modify in real-time the control loop to adapt to the specificity of each particular gyro and the change of the mechanical characteristic of the gyro during its life time. C1 [Keymeulen, Didier; Peay, Chris; Foor, David; Withington, Phil; Yee, Karl; Terrile, Rich] CALTECH, Jet Prop Lab, MS 303-300,4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Trung, Tran] Univ Calif Berkeley, Berkeley, CA USA. [Bakhshi, Alireza] B&A Engn, Sand Dimas, CA 91773 USA. RP Keymeulen, D (reprint author), CALTECH, Jet Prop Lab, MS 303-300,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM didier.keymeulen@jpl.nasa.gov NR 13 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2488 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201106 ER PT S AU Chen, Y Mojaradi, M Aranki, N Kazemian, E Grogan, R Kolawa, E Blalock, B Greenwell, R Westergard, L AF Chen, Yuan Mojaradi, Mohammad Aranki, Nazeeh Kazemian, Ehsan Grogan, Robert Kolawa, Elizabeth Blalock, Benjamin Greenwell, Robert Westergard, Lynett GP IEEE TI Design and qualification methodology for a successful technology infusion for a wide temperature Op-Amp SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In this paper(1,2), we present a methodology for design and qualification of microelectronics for low temperature applications, which has enabled the successful infusion of a custom designed Operational Amplifier into flight mission. The Op-Amp was designed to target a wide temperature range of -150 degrees C to +125 degrees C for at least 5 years operation for Mars Mission. The design and qualification methodology developed have provided the critical path for the technology infusion. C1 [Chen, Yuan; Mojaradi, Mohammad; Aranki, Nazeeh; Kazemian, Ehsan; Grogan, Robert; Kolawa, Elizabeth] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. [Blalock, Benjamin; Greenwell, Robert] Univ Tennessee, Dept Elect & Comp Engn, Knoxville, TN 37996 USA. [Westergard, Lynett] AMI Semicond, Pocatello, ID 83201 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. EM yuan.chen@jpl.nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2518 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201109 ER PT S AU Del Castillo, L West, W Vo, T Hatake, T Mojarradi, M Kolawa, E AF Del Castillo, Linda West, William Vo, Tuan Hatake, Toshiro Mojarradi, Mohammad Kolawa, Elizabeth GP IEEE TI Extreme temperature sensing system for Venus surface missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID IONIC-CONDUCTION; ENHANCEMENT; CAF2 AB Previous Venus Landers used high temperature pressure vessels with passive thermal protection systems and protected conventional electronics, which limited their surface operation life to 127 minutes. The operating life and science return for future Venus surface missions, however, can significantly be increased through the use of high temperature electronics capable of extending the operating range of electronic systems to Venus surface temperatures (up to 480 degrees C). Toward that end, this paper details the development and evaluation (at 480 degrees C) of a stand-alone, high temperature, battery powered, sensor system, including a multi-sensor interface, multiplexer, signal conditioner, and amplifier, that can directly operate at the extremely high temperatures of the Venus surface. This work employs commercial, high temperature sensors, electronic devices, and packaging materials and leverages their operating margin to realize the aforementioned high temperature sensor system. As a result, the technology could rapidly rise through technology readiness level gates for future NASA missions toVenus. (12). C1 [Del Castillo, Linda; West, William; Vo, Tuan; Hatake, Toshiro; Mojarradi, Mohammad; Kolawa, Elizabeth] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Del Castillo, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2525 EP 2530 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201110 ER PT S AU Berger, R Garbos, R Cressler, J Mojarradi, M Peltz, L Blalock, B Johnson, W Niu, GF Dai, F Mantooth, A Holmes, J Alles, M McClusky, P AF Berger, Richard Garbos, Raymond Cressler, John Mojarradi, Mohammad Peltz, Leora Blalock, Ben Johnson, Wayne Niu, Guofu Dai, Foster Mantooth, Alan Holmes, Jim Alles, Mike McClusky, Patrick GP IEEE TI Miniaturized data acquisition system tor extreme temperature environments SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB A data acquisition system is being developed for use on the NASA Lunar-Mars series of missions. The unit will accept inputs from multiple types of sensors, employing three types of input channels that each incorporate programmable elements to accommodate a wider variety of input signals. Based in part on a subsystem called the Remote Health Node (RHN) that was originally developed during the 1990s for use on the now-defunct NASA X-33 "space plane", the Remote Electronics Unit (REU) is being developed using a 0.5 micron Silicon Germanium (SiGe) BiCMOS technology from IBM with a circuit library that has been designed to operate normally across a temperature range from -180 degrees C up through +125 degrees C. (12) This NASA project is one of the Exploration Technology Development Projects (EDTP) associated with NASA's Radiation Hardened Electronics for Space Environments (RHESE) program. A large team combining both University and Industry partners is being led by Dr. John Cressler from the Georgia Institute of Technology. Other University team members include the University of Arkansas, Auburn University, the University of Maryland, the University of Tennessee, and Vanderbilt University. Industry members are BAE Systems, Boeing, Lynguent, and Jet Propulsion Laboratories. IBM is acting as the foundry. The REU will support sixteen input channels, including twelve low speed channels designed for signals in the 1-200 Hz range, two higher speed channels that support inputs up to 5 KHz, and two charge amplifier channels that support piezoelectric transducers up to 5 KHz. All sixteen input channels reside on a single mixed signal ASIC that includes analog-to-digital (A/D) conversion to provide a digital output for back-end processing of the signals. The low speed and high speed channels incorporate a programmable Wheatstone bridge that can be programmed as a 1/4, 1/2, or full bridge, along with variable gain amplifiers. The A/D converter employs a novel Wilkinson architecture that allows 16 inputs without the use of an analog multiplexer, employs common circuitry to minimize die area, and dissipates very little power. The programmable elements of the input channels are controlled by a Field Programmable Gate Array (FPGA) that also provides signals for both sensor stimulation and input channel calibration. These signals are translated to analog values by a pair of digital-to-analog (D/A) converters that reside on each of the low and high speed channels. The stimulus is boosted to higher voltages through use of a,current mirror that employs special high voltage transistors that do not require any special processing steps. Back-end processing will also include a small processor to supply commands and accept data before passing the information on to the main computer via RS485 links. Support of extreme temperatures is achieved through the use of device models that have been extended to cover the desired temperature range, adapted technology ground rules to support long term reliability, and unique packages that are designed for this extended range. The circuitry employs both heterojunction bipolar transistors (HBTs) and field effect transistors (FETs). Where needed, radiation hardened by design (RHBD) techniques are being employed in the circuits to provide mitigation against single event latch-up (SEL), single event upsets (SEU), and total dose accumulation. C1 [Berger, Richard] BAE Syst, 9300 Wellington Rd, Manassas, VA 20110 USA. [Garbos, Raymond] Aura Instrumentat Inc, Mont Vernon, NH USA. [Cressler, John] Georgia Inst Technol, Atlanta, GA 30332 USA. [Mojarradi, Mohammad] Jet Prop Lab, Pasadena, CA USA. [Peltz, Leora] Boeing Inc, Chicago, IL USA. [Blalock, Ben] Univ Tennessee, Knoxville, TN 37996 USA. [Johnson, Wayne; Niu, Guofu; Dai, Foster] Auburn Univ, Auburn, AL 36849 USA. [Mantooth, Alan] Univ Arkansas, Fayetteville, AR 72701 USA. [Holmes, Jim] Lynguent Corp, Portland, OR USA. [Alles, Mike] Vanderbilt Univ, Nashville, TN USA. [McClusky, Patrick] Univ Maryland, College Pk, MD USA. RP Berger, R (reprint author), BAE Syst, 9300 Wellington Rd, Manassas, VA 20110 USA. EM richard.w.berger@baesystems.com NR 11 TC 0 Z9 0 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2531 EP + PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201111 ER PT S AU Muirhead, BK AF Muirhead, Brian K. GP IEEE TI Constellation major technical challenges of 2007 SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper discusses the identification and progress toward resolution of the two of the most significant technical challenges the Constellation Program faced during 2007. Constellation is NASA's program to implement the human exploration of the moon, Mars, and beyond This paper is written from the perspective of the Program Systems Engineer, also known at the Chief Architect, who happens to be from the robotic community of NASA. This paper will briefly provide some background on the Constellation program and describe the Office of the Program Systems Engineer, created to lead major cross program technical issues and to lead the development of the program architecture to the moon and beyond. The paper will focus on two of the major technical challenges of the year. The first is understanding and establishing adequate performance and mass margin for the initial low earth orbit capability, targeted to support ISS, the second is the lunar capability to establish an outpost(s) on the moon including the core elements of the lunar transportation architecture. Other interesting challenges will also be discussed briefly including some parallels and differences between human and robotic cultural approaches to problem solving and systems engineering.(12). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. RP Muirhead, BK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-370, Pasadena, CA 91009 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2559 EP 2565 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201114 ER PT S AU Webb, DJ Smith, EE AF Webb, Dennis J. Smith, Ernest E. GP IEEE TI Constellation Program Mission Operations Project Office, status and support philosophy SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Constellation Program Mission Operations Project Office (CxP MOP) at Johnson Space Center in Houston Texas is preparing to support the CxP mission operations objectives for the CEV/Orion flights, the Lunar Lander, and Lunar surface operations. Initially with the retirement of the Shuttle, the Orion will provide access to the International Space Station, then progress to the lunar missions. While initial CEV mission operations support will be conceptually similar to the Shuttle mission to ISS, we have set a challenge to support the Orion missions to ISS with 50% of the mission operations support currently required for Shuttle missions. Therefore, we are assessing more efficient ways to organize the support and new technologies which will enhance our operations support. This paper will address the status of our preparation for these CxP missions, our philosophical approach to CxP operations support, and some of the technologies we are assessing to streamline our mission operations infrastructure.(12). C1 [Webb, Dennis J.; Smith, Ernest E.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Webb, DJ (reprint author), NASA, Lyndon B Johnson Space Ctr, Mail Code DA4,2101 NASA Pkwy, Houston, TX 77058 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2566 EP 2572 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201115 ER PT S AU Mazanek, DD Goodliff, KE Cornelius, DM AF Mazanek, Daniel D. Goodliff, Kandyce E. Cornelius, David M. GP IEEE TI Descent Assisted Split Habitat lunar lander concept SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Descent Assisted Split Habitat (DASH) lunar lander concept utilizes a disposable braking stage for descent and a minimally sized pressurized volume for crew transport to and from the-lunar surface. The lander can also be configured to perform autonomous cargo missions. Although a braking-stage approach represents a significantly different operational concept compared with a traditional two-stage lander, the DASH lander offers many important benefits. These benefits include improved crew egress/ingress and large-cargo unloading; excellent surface visibility during landing; elimination of the need for deep-throttling descent engines; potentially reduced plume-surface interactions and lower vertical touchdown velocity; and reduced lander gross mass through efficient mass staging and volume segmentation. This paper documents the conceptual study on various aspects of the design, including development of sortie and outpost lander configurations and a mission concept of operations; the initial descent trajectory design; the initial spacecraft sizing estimates and subsystem design; and the identification of technology needs. (12). C1 [Mazanek, Daniel D.; Goodliff, Kandyce E.] NASA, Langley Res Ctr, Multictr Design & Tech Evaluat Teams, MS 462, Hampton, VA 23681 USA. [Cornelius, David M.] Analyt Mech Associates Inc, Hampton, VA 23666 USA. RP Mazanek, DD (reprint author), NASA, Langley Res Ctr, Multictr Design & Tech Evaluat Teams, MS 462, Hampton, VA 23681 USA. EM Daniel.D.Mazanek@nasa.gov; Kandyce.E.Goodliff@nasa.gov; Cornelius@ama-inc.com NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2573 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201116 ER PT S AU Cook, SA Vanhooser, T AF Cook, Stephen A. Vanhooser, Teresa GP IEEE TI The next giant leap: NASA's Ares launch vehicles SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The National Aeronautics and Space Administration (NASA)'s Constellation Program is developing new launch vehicles (Arcs) and spacecraft (Orion) to send astronauts to the Moon, Mars, and beyond. This paper presents plans, projections, and progress toward fielding the Arcs I and Arcs V vehicles, and the Arcs I-X test flight in 2009. NASA is building on both new research and aeronautical capabilities, as well as lessons learned from almost 50 years of aerospace experience. The Arcs Projects Office (APO) completed the Arcs I System Requirements Review (SRR) in 2006 and the System Definition Review in autumn 2007; and will focus on the Preliminary Design Review in 2008. Arcs I is currently being refined to meet safety, operability, reliability, and affordability goals. The Arcs team is simultaneously testing Arcs I elements and building hardware for Arcs I-X, while the Arcs V is in the early design stage, with the team validating requirements and ensuring commonality with Arcs I. Arcs I and V are key to opening the space frontier for peaceful endeavors.(1) (2). C1 [Cook, Stephen A.; Vanhooser, Teresa] NASA, George C Marshall Space Flight Ctr, Ares Projects Off, Huntsville, AL 35812 USA. RP Cook, SA (reprint author), NASA, George C Marshall Space Flight Ctr, Ares Projects Off, Huntsville, AL 35812 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2589 EP 2596 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201117 ER PT S AU Doreswamy, R Self, TA AF Doreswamy, Rajiv Self, Timothy A. GP IEEE TI Ares launch vehicles Lean practices case study SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Ares launch vehicles team, managed by the Ares Projects Office (APO) at NASA Marshall Space Flight Center, has completed the Ares I Crew Launch Vehicle System Requirements Review and System Definition Review and early design work for the Ares V Cargo Launch Vehicle. This paper provides examples of how Lean Manufacturing, Kaizen events, and Six Sigma practices are helping APO deliver a new space transportation capability on time and within budget, while still meeting stringent technical requirements. For example, Lean philosophies have been applied to numerous process definition efforts and existing process improvement activities, including the Ares I-X test flight Certificate of Might Readiness (CoFR) process, risk management process, and review board organization and processes. Ares executives learned Lean practices firsthand, making the team "smart buyers" during proposal reviews and instilling the team with a sense of what is meant by "value-added" activities. Since the goal of the APO is to field launch vehicles at a reasonable cost and on an ambitious schedule, adopting Lean philosophies and practices will be crucial to the Ares Project's long-term success.(1 2). C1 [Doreswamy, Rajiv; Self, Timothy A.] NASA, George C Marshall Space Flight Ctr, Ares Projects Off, Huntsville, AL 35812 USA. RP Doreswamy, R (reprint author), NASA, George C Marshall Space Flight Ctr, Ares Projects Off, Huntsville, AL 35812 USA. NR 9 TC 0 Z9 0 U1 2 U2 7 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2597 EP 2603 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201118 ER PT S AU Wilcox, BR Schneider, EG Vaughan, DA Hall, JL AF Wilcox, Brian R. Schneider, Evan G. Vaughan, David A. Hall, Jeffrey L. GP IEEE TI Low-cost propellant launch to Earth orbit from a tethered balloon - an update SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB As previously reported [1], it may be possible to launch payloads into low-Earth orbit (LEO) at a per-kilogram cost that is one to two orders of magnitude lower than current launch systems, using only a relatively small capital investment (comparable to a single large present-day launch).(12) An attractive payload would be large quantities of high-performance rocket propellant as required for the exploration of the moon, Mars, and beyond. The concept is to use small mass-produced rockets that can reach orbit with modest atmospheric drag losses because they are launched from high altitude (e.g. 22 km). These small rockets launch from this altitude by being winched up a tether to a balloon. The drag losses on a rocket are strongly related to the ratio of the rocket launch mass to the mass of the atmospheric column displaced as the vehicle ascends from the launch site to orbit. By reducing the mass of this atmospheric column to a few percent of what it would be launching from sea level, the mass of the rocket can be proportionately reduced while maintaining the drag loss at an acceptably small level. C1 [Wilcox, Brian R.; Schneider, Evan G.; Vaughan, David A.; Hall, Jeffrey L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilcox, BR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2624 EP 2637 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201120 ER PT S AU Gorinevsky, D Hoffmann, GM Shmakova, M Mah, RW Cryan, S Mitchell, JD AF Gorinevsky, Dimitry Hoffmann, Gabriel M. Shmakova, Marina Mah, Robert W. Cryan, Scott Mitchell, Jennifer D. GP IEEE TI Fault tolerance of relative navigation sensing in docking approach of spacecraft SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SYSTEMS; DESIGN AB This paper analyzes fault tolerance of spacecraft relative navigation in Automated Rendezvous and Docking (AR&D). The relatively low technology readiness of existing relative navigation sensors for AR&D has been carried as one of the NASA Crew Exploration Vehicle Project's top tasks. Fault tolerance could be enhanced with the help of FDIR (Fault Detection, Identification and Recovery) logic and use of redundant sensors. Because of mass and power constraints, it is important to choose a fault tolerant design that provides the required reliability without adding excessive hardware. An important design trade is determining whether a redundant sensor can be normally unpowered and activated only when necessary. This paper analyzes reliability trades for such fault tolerant system. A Markov Chain model of the system is composed of sub-models for sensor faults and for sensor avionics states. The sensor fault sub-model parameters are based on sensor testing data. The avionics sub-model includes FDIR states; the parameters are determined by Monte Carlo simulations of the near field docking approach. The integrated Markov Chain model allows the probabilities of mission abort and a mishap to be computed. The results of the trade study include dependence of the probabilities on the backup sensor activation delay. C1 [Gorinevsky, Dimitry; Hoffmann, Gabriel M.; Shmakova, Marina] Mitek Analyt LLC, Palo Alto, CA 94306 USA. [Gorinevsky, Dimitry] Stanford Univ, EE Dept, Stanford, CA 94305 USA. [Shmakova, Marina] Stanford Univ, Dept Phys, Stanford, CA 94305 USA. [Mah, Robert W.] NASA, Ames Res Ctr, Mountain View, CA USA. [Cryan, Scott; Mitchell, Jennifer D.] NASA, Johnson Space Ctr, Houston, TX USA. [Hoffmann, Gabriel M.] Stanford Univ, AA Dept, Stanford, CA 94305 USA. RP Gorinevsky, D (reprint author), Mitek Analyt LLC, Palo Alto, CA 94306 USA. EM dimitry@mitekan.com NR 25 TC 0 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2695 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201127 ER PT S AU Brewster, LL Howard, RT Johnston, AS Carrington, C Mitchell, JD Cryan, SP AF Brewster, Linda L. Howard, Richard T. (Nick) Johnston, A. S. Carrington, Connie Mitchell, Jennifer D. Cryan, Scott P. GP IEEE TI Multi-sensor testing for automated rendezvous and docking sensor testing at the flight robotics lab SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-loop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockap that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS.(1) The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (1) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multi-sensor series of trajectories.(2). C1 [Brewster, Linda L.; Howard, Richard T.; (Nick) Johnston, A. S.; Carrington, Connie] NASA, George C Marshall Space Flight Ctr, MSFC, Bldg 4619,MC ES62, Huntsville, AL 35812 USA. [Mitchell, Jennifer D.; Cryan, Scott P.] NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Brewster, LL (reprint author), NASA, George C Marshall Space Flight Ctr, MSFC, Bldg 4619,MC ES62, Huntsville, AL 35812 USA. EM linda.brewster@nasa.gov NR 2 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2704 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201128 ER PT S AU Wilcox, BR AF Wilcox, Brian R. GP IEEE TI ATHLETE: An option for mobile lunar landers SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB As part of the NASA Exploration Technology Development Program, the Jet Propulsion Laboratory is developing a vehicle called ATHLETE: the All-Terrain Hex-Limbed Extra-Terrestrial Explorer. 1 2 Each vehicle is based on six wheels at the ends of six multi-degree-of-freedom limbs. Because each limb has enough degrees of freedom for use as a general-purpose leg, the wheels can be locked and used as feet to walk out of excessively soft or other extreme terrain. Since the vehicle has this alternative mode of traversing through or at least extracting itself out of extreme terrain, the wheels and wheel actuators can be sized for nominal terrain. There are substantial mass savings in the wheel and wheel actuators associated with designing for nominal instead of extreme terrain. These mass savings are comparable-to or larger-than the mass increase of the articulated limbs. As a result, the entire mobility system, including wheels and limbs, can be lighter than a conventional mobility chassis. In addition, each limb has sufficient degrees-of-freedom to use as a general-purpose manipulator. Our prototype ATHLETE vehicles have quick-disconnect tool adapters on the limbs that allow tools to be drawn out of a "tool belt" and positioned by the limb. A power-take-off from the wheel actuates the tools, so that they can take advantage of the 1+ horsepower motor in each wheel to enable drilling, gripping or other power-tool functions. One of the most attractive uses for ATHLETE limbs is as part of a "mobile lander". Lunar landers are traditionally conceived-of as static - remaining stationary after landing on pads that deploy to a large radius to reduce the likelihood of overturning and that incorporate energy absorption (e.g. crushable materials) to cushion whatever residual impact remains after the rocket propulsion system is shut down. Landers implicitly integrate all the subsystems required for a complete spacecraft - power, communications, computation, inertial sensing, etc. All these subsystems would need to be re-implemented on any rover that deploys from a lander. Instead, these subsystems can be used "as-is" (perhaps with additional qualification testing) if only the lander were equipped with post-landing mobility. This obvious advantage of mobile landers has been recognized for decades (see Section 3), but use of ATHLETE limbs as landing outriggers together with crushable materials under the primary structure of the lander combines the benefits of the reduced mobility mass and tool-use of the ATHLETE concept with the intrinsic efficiency of the mobile lander concept. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Wilcox, BR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr M-S 303-300818-354-4625, Pasadena, CA 91125 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2711 EP 2718 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201129 ER PT S AU Garcia-Galan, C Armstrong, RE Lammers, ML McMillan, CR AF Garcia-Galan, Carlos Armstrong, Robert E. Lammers, Michael L. McMillan, Courtenay R. GP IEEE TI Operational lessons learned for systems management and automation on manned spacecraft SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB over the last four decades of human spaceflight, the capabilities and complexity of manned spacecraft systems have increased significantly to meet the evolving requirements of the mission. The management of the vehicle systems, both by the crew on-board and the operators in the Mission Control Center (MCC), has also evolved to take advantage of new capabilities, or simply to react to the features of the spacecraft design. 12 As we embark in a new era of space exploration, with firm plans for the development of a new fleet of spacecraft intended to carry out the objectives of the Constellation program, it is relevant to examine important lessons learned on the design and management of manned spacecraft systems and the mission. This paper will focus on lessons learned related to system management capabilities that directly impact crew safety, mission success and/or improve operability of the spacecraft. In particular, the authors will examine current system design features, capabilities and processes that provide valuable capabilities or create operational challenges for the current manned spacecraft operated by NASA; the Space Transportation System (STS) (a.k.a. the Space Shuffle) and the International Space Station (ISS). Furthermore, it is important to analyze relevant events for which specific design capabilities have enabled safety or mission success, and others where system or process anomalies led to reduced system capabilities or operational challenges. A notable example of such events are the recent on-board Command and Control (C&C) computer anomalies in ISS, both on the US (during mission ISS 6A) and Russian segments (mission ISS 13A). For such events, it is important to understand the root-cause of the problem, to avoid it in future designs. However, it is more relevant to understand what aspects of the design led to the mitigation or further propagation of the impact of the failure, and the capabilities that enabled the team to recover from the anomalies. Moreover, relevant lessons learned are equally beneficial to standard practices or specific system capabilities that provide enabling tools for safer and more efficient operations. The purpose of this paper is to identify relevant operational lessons learned from current architectural designs and processes. For that purpose, the authors combine the discussion of "real-life" events, along with selected standard desired design features, to provide an illustration of capabilities that should be considered during the design and implementation of future spacecraft, including the Crew Exploration Vehicle (CEV) and other elements of the Constellation Program. C1 [Garcia-Galan, Carlos; Armstrong, Robert E.; Lammers, Michael L.; McMillan, Courtenay R.] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Garcia-Galan, C (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 5 TC 0 Z9 0 U1 0 U2 8 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2719 EP 2732 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201130 ER PT S AU Tripathi, RK Nealy, JE AF Tripathi, Ram K. Nealy, John E. GP IEEE TI Mars radiation risk assessment and shielding design for long-term exposure SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA is now focused on the agency's vision for space exploration encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. As a result, there is a focus on long duration space missions. NASA is committed to the safety of the missions and the crew, and there is an overwhelming emphasis on the reliability issues for space missions and the habitat. The cost-effective design of the spacecraft demands a very stringent requirement on the optimization process. Exposure from the hazards of severe space radiation in deep space and/or long duration missions is a critical design constraint and a potential 'show stopper.' Thus, protection from the hazards of severe space radiation is of paramount importance to the agency's vision. It is envisioned to have long duration human presence on the Moon for deep space exploration. The exposures from ionizing radiation galactic cosmic radiation and solar particle events - and optimized shield design for a swing-by and a long duration Mars mission have been investigated. It is found that the technology of today is inadequate for safe human missions to Mars, and revolutionary technologies need to be developed for long duration and/or deep space missions. The study will provide a guideline for radiation exposure and protection for long duration missions and career astronauts and their safety.(12). C1 [Tripathi, Ram K.; Nealy, John E.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Tripathi, RK (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 15 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2733 EP 2741 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201131 ER PT S AU Comstock, DA AF Comstock, Douglas A. GP IEEE TI Technology development and infusion from NASA's innovative partnerships program SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's Innovative Partnerships Program (IPP) develops many technologies for NASA's programs and projects through a portfolio of technology investments and partnerships. The investment portfolio includes Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR), the IPP Seed Fund, and NASA's Centennial Challenges prize program. In the process of technology development and infusion, the transition of technologies from laboratories or testbeds to their application in flight programs is often one of the most challenging steps. Newly developed technologies achieve full success when they are infused into programs and projects, although there are numerous obstacles to achieving infusion. This paper(1,2) addresses the IPP portfolio for providing technology, the challenges and obstacles to technology infusion, and some of the methods currently being employed by NASA to help address those challenges and obstacles. The paper also presents some examples of IPP technologies infused into high profile programs and projects and draws lessons learned and best practices from those successful examples. C1 NASA, Washington, DC 20546 USA. RP Comstock, DA (reprint author), NASA, Headquarters 300 E St,SW, Washington, DC 20546 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2742 EP 2752 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201132 ER PT S AU Howard, RT Heaton, AF Pinson, RM Carrington, CK AF Howard, Richard T. Heaton, Andrew F. Pinson, Robin M. Carrington, Connie K. GP IEEE TI Orbital express advanced video guidance sensor SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In May 2007 the first US-sponsored fully autonomous rendezvous and capture was successfully performed by DARPA's Orbital Express (OE) mission. For the following three months, the Boeing ASTRO spacecraft and the Ball Aerospace NEXTSat performed multiple rendezvous and docking maneuvers to demonstrate some of the technologies needed for satellite servicing. MSFC's Advanced Video Guidance Sensor (AVGS) was a near-field proximity operations sensor integrated into ASTRO's Autonomous Rendezvous and Capture Sensor System (ARCSS), which provided relative state knowledge to the ASTRO GN&C system. AVGS was one of the primary docking sensors included in ARCSS. This paper provides an overview of the AVGS sensor that flew on Orbital Express, a summary of the AVGS ground testing, and a discussion of AVGS performance on-orbit for OE.(1 2) The AVGS is a laser-based system that is capable of providing bearing at midrange distances and full six degree-of-freedom (6-DOF) knowledge at near ranges. The sensor fires lasers of two different wavelengths to illuminate retro-reflectors on the Long Range Target (LRT) and the Short Range Target (SRT) mounted on NEXTSat. The retro-reflector filters allow one laser wavelength to pass through and be reflected, while blocking the other wavelength. Subtraction of one return image from the other image removes extraneous light sources and reflections from anything other than the corner cubes on the LRT and SRT. The very bright spots that remain in the subtracted image are processed to provide bearing or 6-DOF relative state information. AVGS was operational during the Orbital Express unmated scenarios and the sensor checkout operations. The OE unmated scenarios ranged from 10 meters to 7 kilometers ending in either a docking or a free-flyer capture. When the target was pointed toward the AVGS and in the AVGS operating range and Field-of-View (i.e. along the Approach Corridor of the NEXTSat), the AVGS provided full 6-DOF measurements. The AVGS performed very well during the sensor check-out operations, effectively tracking beyond its 10-degree Pitch and Yaw limit-specifications. AVGS also provided excellent performance during the unmated operations, effectively tracking its targets, and showing good agreement between the SRT and LRT data. The AVGS consistently exceeded the tracking range expectations for both the SRT and LRT. During the approach to re-mate in Scenario 3-1 Recovery the AVGS began tracking the LRT at 150 m, well beyond the OE specified operational range of 120 meters, and functioned as the primary sensor for the autonomous rendezvous and docking. For all scenarios, the AVGS was used while ASTRO was in the approach corridor to NEXTSat, and during close proximity operations and docking. C1 [Howard, Richard T.; Heaton, Andrew F.; Pinson, Robin M.; Carrington, Connie K.] NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Howard, RT (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 3 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2784 EP 2793 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201136 ER PT S AU Bryan, TC Howard, R Johnson, JE Lee, JE Murphy, L Spencer, SH AF Bryan, Thomas C. Howard, Richard Johnson, Jimmie E. Lee, James E. Murphy, Lucinda Spencer, Susan H. GP IEEE TI Next Generation Advanced Video Guidance Sensor SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express (OE) in May of 2007, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. The United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transportation Services (COTS) Automated Rendezvous and Docking (AR&D).(1 2) Video-based sensors have been under regular development, testing, and upgrading at Marshall Space Flight Center (MSFC) for almost 20 years. The first sensor flown was the Video Guidance Sensor (VGS) in 1997, followed by the AVGS on the Demonstration of Autonomous Rendezvous Technologies (DART) mission in 2005 [2]. AVGS has a proven pedigree, based on extensive ground testing and flight demonstrations. The AVGS on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 kin. The first generation rendezvous and docking sensor, the VGS, was developed and successfully flown on Space Shuttle flights in 1997 and 1998. Parts obsolescence issues prevent the construction of more AVGS units, and the next generation sensor must be updated to support the CEV and COTS programs. The flight proven AR&D sensor is being redesigned to update parts and add additional capabilities for CEV and COTS with the development of the Next Generation AVGS (NGAVGS) at MSFC. The obsolete imager and processor are being replaced with new radiation tolerant parts. In addition, new capabilities might include greater sensor range, auto ranging, and real-time video output. This paper presents an approach to sensor hardware trades, use of highly integrated laser components, and addresses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It will also discuss approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, parts selection and test plans for the NGAVGS will be addressed to provide a highly reliable flight qualified sensor. Expanded capabilities through innovative use of existing test capabilities will also be discussed along with some of the test results achieved during the preliminary development of the NGAVGS. C1 [Bryan, Thomas C.; Howard, Richard] NASA Bldg 4619, George C Marshall Space Flight Ctr, Autonomous Rendezvous & Docking Dev & Test Branch, Huntsville, AL USA. [Johnson, Jimmie E.; Lee, James E.; Spencer, Susan H.] NASA, Marshall Space Flight Ctr, Explorat Adv Capabil Off VP33, Huntsville, AL USA. [Murphy, Lucinda] NASA, Marshall Space Flight Ctr, Project Engn Branch ES11, Huntsville, AL USA. RP Bryan, TC (reprint author), NASA Bldg 4619, George C Marshall Space Flight Ctr, Autonomous Rendezvous & Docking Dev & Test Branch, Huntsville, AL USA. EM tom.bryan@nasa.gov; ricky.howard@nasa.gov; jimmie.e.johnson@nasa.gov; james.e.lee@nasa.gov; lucinda.m.murphy@nasa.gov; susan.h.spencer@nasa.gov NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2794 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201137 ER PT S AU Ho, SS Talukder, A AF Ho, Shen-Shyang Talukder, Ashit GP IEEE TI Automated cyclone identification from remote QuikSCAT satellite data SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID MODEL AB We discuss a fully automated remote cyclone identification and tracking approach using the QuikSCAT wind sensor data. Our approach consists of five main automated steps: QuikSCAT data retrieval, QuikSCAT feature extraction & data preprocessing, cyclone identification, motion/location prediction, and cyclone tracking. Ensemble learning based on a committee of support vector machines using features extracted from QuikSCAT wind sensor data are used for cyclone identification. Experimental results demonstrates the feasibility and usefulness of our automated approach. C1 [Ho, Shen-Shyang; Talukder, Ashit] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ho, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Ave 300-123, Pasadena, CA 91109 USA. RI Ho, Shen-Shyang/B-7034-2012 OI Ho, Shen-Shyang/0000-0002-0353-7159 NR 16 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2813 EP 2821 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201139 ER PT S AU Pingree, PJ Scharenbroich, LJ Werne, TA Hartzell, C AF Pingree, Paula J. Scharenbroich, Lucas J. Werne, Thomas A. Hartzell, Christine GP IEEE TI Implementing legacy-C algorithms in FPGA co-processors for performance accelerated smart payloads SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Accurate, on-board classification of instrument data is used to increase science return by autonomously identifying regions of interest for priority transmission or generating summary products to conserve transmission bandwidth. Due to on-board processing constraints, such classification has been limited to using the simplest functions on a small subset of the full instrument data. FPGA co-processor designs for SVM1 classifiers will lead to significant improvement in on-board classification capability and accuracy. We implemented a SWIL2 classifier, developed for the Hyperion instrument on the EO-1 spacecraft, on the Xilinx Virtex-4FX60 FPGA as a baseline challenge. We have taken advantage of Impulse C (TM), the commercially available C-to-HDL tool by Impulse Accelerated Technologies, which supports the development of highly parallel, co-designed hardware algorithms (from software) and applications. This paper describes our approach for implementing the Hyperion linear SVM on the Virtex-4FX FPGA, as well as additional experiments with increased numbers of data bands and a more sophisticated SVM kernel to show the potential for better on-board classification achieved with embedded FPGAs over current in-flight capabilities.(3,4). C1 [Pingree, Paula J.; Scharenbroich, Lucas J.; Werne, Thomas A.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Hartzell, Christine] Georgia Inst Technol, Atlanta, GA 30332 USA. RP Pingree, PJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Paula.J.Pingree@jpl.nasa.gov; LucasJ.Scharenbroich@jpl.nasa.gov; ThomasA.Werne@jpl.nasa.gov; Gtg733w@mail.gatech.edu NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2822 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201140 ER PT S AU Castano, R Estlin, T Gaines, D Bornstein, B Anderson, RC Bue, B Judd, M AF Castano, Rebecca Estlin, Tara Gaines, Dan Bornstein, Ben Anderson, Robert C. Bue, Brian Judd, Michele GP IEEE TI Experiments in onboard rover traverse science SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Onboard Autonomous Science Investigation System (OASIS) evaluates geologic data gathered by a planetary rover. This analysis is used to prioritize the data for transmission, so that the data with the highest science value is transmitted to Earth. In addition, the onboard analysis results are used to identify science opportunities. A planning and scheduling component of the system enables the rover to take advantage of identified science opportunities. in this paper, we provide a brief overview of the entire OASIS system, and then describe new system capabilities with an emphasis on the identification of novel features during a traverse. This capability has been integrated into the full system and validated in field testing. In addition, the system has been integrated with the Visual Target Tracking (VTT) capability recently uploaded to the Mars Exploration Rovers. VTT enables the system to robustly track a specified target. By integrating this with the autonomous science system, the rover can approach targets identified onboard and acquire targeted measurements both from additional viewing angles as well as from positions in close proximity to the target.(1) (2). C1 [Castano, Rebecca; Estlin, Tara; Gaines, Dan; Bornstein, Ben; Anderson, Robert C.; Bue, Brian; Judd, Michele] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Castano, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2830 EP 2839 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201141 ER PT S AU Lee, S Bornstein, B AF Lee, Seungwon Bornstein, Benjamin GP IEEE TI Autonomous calibration of Vehicle Cabin Atmosphere Monitor SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Vehicle Cabin Atmosphere Monitor (VCAM) is designed to autonomously detect and identify trace organic species in the International Space Station (ISS) cabin air and monitor changes in species concentrations over time after chemical events. VCAM uses a gas chromatograph and quadrupole ion trap mass spectrometer to separate chemical analytes and determine mass fractionation patterns of the chemical analytes. In order to obtain the desired mass resolution and dynamic range, several instrument parameters must be calibrated. We present our lessons learned developing a heuristic calibration procedure and translating the procedure into a procedure suitable for direct conversion to flight software. The heuristic procedure involves the detection of changes in signal trends that humans can easily recognize, but are not necessarily straightforward to codify in an algorithm. We developed an algorithm by working closely with instrument experts and designed several test cases and data sets to verify that the algorithm achieved the same as the original human heuristics.(1) (2). C1 [Lee, Seungwon; Bornstein, Benjamin] Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, S (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2840 EP 2847 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201142 ER PT S AU Bornstein, B Lee, S Mandrake, L Bue, B AF Bornstein, Benjamin Lee, Seungwon Mandrake, Luke Bue, Brian GP IEEE TI Autonomous identification and quantification of chemical species with VCAM for use onboard the ISS SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID COMPOUND IDENTIFICATION; MASS-SPECTROMETRY; EXTRACTION AB The Vehicle Cabin Atmosphere Monitor (VCAM) instrument is designed to autonomously detect and identify trace organic species in the International Space Station (ISS) cabin air and monitor changes in species concentrations over time after chemical events. The physical instrument is comprised of two subsystems. The first subsystem is a preconcentrator gas chromatograph (PCGC) which separates chemical analytes in time, based on compound specific properties such as molecular weight. The second subsystem is a Mass Spectrometer (MS) which measures the abundance of ionized analytes, separated in the GC phase, at specific mass-to-charge ratios. The VCAM PCGC/MS produces a time-series of mass fractionation patterns, indicative of the chemical compounds present, which is used for subsequent compound detection, identification, and quantification. In order to autonomously identify and quantify chemical species from the PGGC/MS data, VCAM employs a variant of the de-facto industry standard Automated Mass Spectral Deconvolution and Identification System (AMDIS) algorithm developed by the National Institute of Standards and Technology (NIST). AMDIS was chosen first for its superior performance, when compared to a neural network classifier developed in-house and a proprietary, third-party, commercial algorithm, and second for its reputation within the mass spectrometry community. In this paper we provide an overview of AMDIS, including GC peak identification and spectral matching, as well our variations and additions to the core algorithm for performing mass calibration beforehand and species quantification afterward. We also discuss some of the challenges faced creating an independent implementation of AMDIS for delivery to VCAM flight software. Testing our algorithm, both individual components and in its entirety, was a particularly challenging, as the VCAM instrument was still in development and only periodically able to produce validation datasets(12). C1 [Bornstein, Benjamin; Lee, Seungwon; Mandrake, Luke; Bue, Brian] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bornstein, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2848 EP 2855 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201143 ER PT S AU Alena, R Ellis, SR Hieronymus, J Maclise, D AF Alena, Richard Ellis, Steven R. Hieronymus, Jim Maclise, Dougal GP IEEE TI Wireless avionics and human interfaces for inflatable spacecraft SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Revolutionary capabilities for robust control of inflatable Lunar and Martian transit vehicles and planetary habitats can be developed using advanced wireless network technology and modular avionics coupled with facile human to system interfaces. Fully wireless modular avionics would eliminate any cabling associated with power and data transmission, allowing easy deployment of flexible control systems and human interfaces. Furthermore, wearable human interface systems hosting virtual reality interaction methods can provide significant improvement in human situational awareness and control of dynamic space systems. The crew can interact with intelligent software agents providing human-like interaction using speech. These advanced information management systems would incorporate intelligent software agents to assist the crew in performing vehicle and mission operations. Advances in robust wireless data communications and wireless power transmission are the key technologies that enable this new spacecraft architecture. This paper will cover the proposed architecture for wireless spacecraft avionics including innovative human interaction techniques with spacecraft systems. The team believes these two aspects are intimately related and that mobile virtual human interfaces can solve many problems associated with operating spacecraft based on inflatable structures. Conventional architectures allocate much space to a cockpit from which the spacecraft is piloted and monitored. For the transit to Mars, which in most scenarios takes approximately 6 months, the cockpit becomes a major consumer of available space while being used only briefly during the journey for earth departure and planetary approach. Wireless control of the spacecraft would allow the piloting and monitoring function to be carried out from any location within the crew space. Identifying key technology developments required to support this architecture will involve evaluating current and next generation wireless networks, computational modules and wireless power transmission for avionics. Complementary methods for virtual human interfaces will be evaluated, with the rapid development of this technology enabling significant advances to be realized in the next decade.(12) For piloting and monitoring functions it will be necessary to have virtual reality for looking outside the transit ship. Because of the radiation shielding required beyond the atmosphere and magnetosphere, there will be no clear view to the outside of the spacecraft. The visual capability will have to be provided by remote presence technology, which ties the virtual reality visual system with cameras on the outside of the craft. Spoken commanding and interaction with ship systems is also an important part of this concept. As ship systems become more complex, it will become impossible for the crew to remember exact details of all aspects of the operating environment. in this case the ability to ask questions about spacecraft status and have the agents issue audible spoken advisories and warnings becomes an important part of safely operating a very complex system. The shipboard agent systems can become in effect a much larger crew for the mission. With the round trip communication times approaching 40 minutes for the Mars transit, all of the mission operations knowledge will have to be built into the spacecraft, lessening dependence upon earth-based support. The operational authority has to be given to the astronauts augmented by virtual mission support provided by the knowledge agents on the spacecraft. A distributed wireless avionics system would provide the computational capacity for sophisticated support systems that inform the correct crewmember of a problem needing their attention, and to assist them in performing a complex task. C1 [Alena, Richard; Ellis, Steven R.; Hieronymus, Jim; Maclise, Dougal] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Alena, R (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 12 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2864 EP 2879 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201145 ER PT S AU Cholakian, T Gallon, J AF Cholakian, Tanya Gallon, John GP IEEE TI Mars Science Laboratory Roll Control System thruster seals SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB During atmospheric entry into Mars, Mars Science Laboratory (MSL) requires a dynamic seal around the Roll Control System (RCS) thrusters. The RCS thrusters are mounted on the Descent Stage which is on the inside of Backshell. The thrusters protrude slightly through cutouts in the Backshell. The seal is mounted on the Backshell and interfaces with an aerodynamic shroud that surrounds the thruster nozzle ends. The seal's main requirement is to aid in blocking the aero-thermal heating during atmospheric entry from entering into the Backshell. The seal must also be able to take the heat loading that is subjected by the thruster themselves, in addition to being a dynamic seal as there are relative deflections on the order of 6.5mm (designed to handle 15mm) across the sealing interface. The seal design is comprised of thin titanium shim stock that is arranged in a staggered-shingled blade configuration that flexes, absorbs relative motion, and seals gaps between blades. Analysis and testing was performed to validate the design's capability to perform as required during atmospheric entry into Mars(12). C1 [Cholakian, Tanya; Gallon, John] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cholakian, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2923 EP 2928 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201151 ER PT S AU Quicksall, JJ Gallon, JC AF Quicksall, J. J. Gallon, J. C. GP IEEE TI Guide rails for linear separation of Powered Descent Vehicle from Mars Science Laboratory Backshell SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB During descent through the Martian atmosphere, Mars Science Laboratory (MSL) uses three sets of guide rails and rollers to control the separation dynamics of the Powered Descent Vehicle (PDV) from the Backshell and parachute. The guided linear separation of the two bodies over a distance of half a meter mitigates the risk of re-contact which could result in unexpected and detrimental vehicle dynamics. The guide rails are comprised of three thin beams oriented in 120 degree intervals around the circumference of the Backshell's internal structure, and they interface with three sets of four rollers mounted on the exterior of the PDV. This configuration resists motion in 5 DOF. The only unconstrained DOF is in the direction of desired separation. Analysis was used to size the guide rail and rollers, and tests will be performed to validate the design's capability to perform as required during the dynamic separation event(12). C1 [Quicksall, J. J.; Gallon, J. C.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quicksall, JJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2929 EP 2934 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201152 ER PT S AU Gallon, JC Umland, J Cholakian, T AF Gallon, John C. Umland, Jeff Cholakian, Tanya GP IEEE TI Testing and analysis of separation joints for Mars Science Laboratory SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Each of the separating subsystems on the Mars Science Laboratory incorporates the use of separation joints. These joints serve as the structural connection between the mating subsystems during all dynamic loading prior to separation. Once the separation command is given, the structural connection is severed via actuation of pyrotechnic release nuts that let loose the structural bolts that hold the subsystems together. The use of a cup-and-cone design is utilized at the subsystem interfaces. Analysis and testing was performed to capture the stresses and deflection of the separation joint hardware under maximum shear loading. Testing included the use of an instrumented bolt that allowed bending moments down the length of the shank to be captured while the joint slipped from induced shear loading until the cup-and-cones engaged and took the shear across the joint. Extensometers were also used to capture the shear displacement of the structures to capture the slip event as well as elastic deflection of the cup-and-cone and parent structure. An analytical model was created and validated based on the test results. This analytical model was then used to calculate the structural margins of the separation joint at each of the subsystem's separation pianes(12). C1 [Gallon, John C.; Umland, Jeff; Cholakian, Tanya] NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gallon, JC (reprint author), NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2935 EP 2942 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201153 ER PT S AU Roberts, ET Gallon, JC AF Roberts, Eric T. Gallon, John C. GP IEEE TI Mars Science Laboratory Heat Rejection System (HRS) tubing retractor SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In support of the Cruise Stage form Entry Vehicle separation event for Mars Science Laboratory (MSL), two 3/8" aluminum tubes that are part of the Heat Rejection System (HRS) must be cut and retracted. Due to size and stiffness of the tubes to be retracted and the mass and volume constraints on MSL, the typical preloaded spring retraction mechanism was deemed to not be the ideal mechanism. Instead a pyrotechnic thruster was designed to perform the job. This thruster was baselined from the design details of an existing 5/8" cable cutter, but highly modified to meet the needs of the retraction device. Due to the added kinetic energy of an increased stroke, as compared to the cutter, a new attenuator to absorb the residual energy at the end of stroke had to be designed to keep the thruster housing from yielding. Volume constraints limited the size of the attenuator so the typical honeycomb crushable was not an option. Instead a collapsing thin walled tube design was analyzed, tested and implemented. Part of the analysis and testing was the process of correlating the difference between static and dynamic flow stresses of the attenuator material as well as the collapse modes of the cylinder walls. Upon completion of the preliminary attenuator design, proof of concept testing was done to validate the design of the retraction system such that the thruster has adequate capability to retract the HRS lines away from the Entry Vehicle. In that process the attenuator was also validated to absorb the majority of the thruster's energy as not to yield any other components of the devise. C1 [Roberts, Eric T.] Flight Hardware Engn Inc, 381 Pershing Dr, Playa Del Rey, CA 90293 USA. [Gallon, John C.] Jet Prop Lab, Pasadena, CA 91109 USA. RP Roberts, ET (reprint author), Flight Hardware Engn Inc, 381 Pershing Dr, Playa Del Rey, CA 90293 USA. EM EricRobertsFHW@gmail.com; john.c.gallon@jpl.nasa.gov NR 1 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2943 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201154 ER PT S AU Shafer, MW AF Shafer, Michael W. GP IEEE TI Passive management of deployable cordage during and after MSL touchdown SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's next generation Mars rover will land unlike any previous mission. A rocket powered descent stage will lower the rover on three bridles as it flies toward the ground. An electrical umbilical cable will be deployed as well to keep the descent stage and rover in communication. Once on the ground, the rover will cut all soft-good lines, allowing the descent stage to fly clear of the rover. The management of these cables from the moment of rover touchdown until the descent stage has flown clear required a great deal of attention. Slack from these soft-goods could not accumulate on the rover deck and the lines had to avoid both the rover and descent stage during flyaway. The bridles were managed by two systems. One kept tension on all together from within the descent stage. The other, on the rover deck, was able to individually tension each of the bridles. The umbilical management system relied on a single tensioning mechanism within the descent stage. This mechanism was specifically sized such that it simultaneously moved the umbilical away from the rover and descent stage during fly-away. It also had to be sized to manage transient slack at touchdown. As a result, the effects of peak retraction force on these performance characteristics were quantified. Additionally, the umbilical had to be designed to survive the loads associated with deployment and slack management. Finally, a model was developed to characterize the profile of the umbilical during the descent stage fly-away event to understand potential rover deck recontact locations. Those pieces of deck hardware that had the potential to be impacted by the umbilical were identified and recommendations were made as to how to avoid snagging the umbilical(12). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shafer, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove,M-S 422-R, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2951 EP 2966 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201155 ER PT S AU Kern, DL Gerace, CA AF Kern, Dennis L. Gerace, Christopher A. GP IEEE TI Implementation of a whole spacecraft isolation system for the OSTM/Jason 2 mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The OSTM/Jason 2 mission will be the lightest payload to ever launch on a 2-stage Delta II 7320-10 launch vehicle. The moment-based lateral loads predicted for this launch configuration significantly exceed the qualification history of the inherited spacecraft bus. Additionally, payload sine vibration requirements for this launch configuration exceed the OSTM/Jason 2 spacecraft and equipment sine vibration qualification heritage. C1 [Kern, Dennis L.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 157-410, Pasadena, CA 91109 USA. [Gerace, Christopher A.] Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Kern, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 157-410, Pasadena, CA 91109 USA. EM dennis.l.kern@jpl.nasa.gov; christopher.a.gerace@nasa.gov NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2967 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201156 ER PT S AU Dahya, N Roberts, ET AF Dahya, Neil Roberts, Eric T. GP IEEE TI Design and fabrication of the cruise stage spacecraft for MSL SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Mars Science Laboratory (MSL) is a scientific mission that will deliver a roving science platform to the surface of Mars. In order to accomplish this mission, the rover must be safely transported from the surface of Earth to the surface of Mars. To achieve this, a Launch Vehicle, Cruise Stage, Entry Vehicle, which is comprised of an Aeroshell,Parachute, and Descent Stage must be employed. The Cruise Stage, Descent Stage and Rover are being designed and assembled at the Jet Propulsion Laboratory in Pasadena, California, while the Aeroshell is being designed and built by Lockheed Martin in Denver, Colorado, and the Parachute is being designed and built by Pioneer Aerospace in South Windsor, Connecticut. The primary function of the Cruise stage is to interface to the Launch Vehicle, and provide the structural load path to the Entry Vehicle, during the launch phase of the mission and then to provide power, telecommunications, navigation and propulsion for the 9 month journey from Earth to Mars, and lastly to orient the Entry Vehicle for Mars Atmospheric entry before burning up in the Mars atmosphere. The Cruise Stage design was based on the heritage Cruise Stages from the Mars Pathfinder (MPF) and Mars Exploration Rover (MER) Missions. These spacecrafts were composed of a similar architecture and provided the same functions, However both MPF and MER Cruise Stages were a 2.75m diameter by 10cm high spacecraft while the MSL Cruise Stage is 4.40m diameter by 60cm. high spacecraft. This size is driven by the size of the MSL Rover which will be the largest vehicle delivered to the Mars surface to date. The key challenges in the MSL cruise stage reside in reacting to the loads from a 3400kg Entry Body, interfacing to a new launch vehicle, meeting the new alignment requirements for GNC, defining the structure configuration and assembly process, and the design and build of the assembly tooling for such a large structure. This paper describes the design and assembly of the Cruise Stage along with how the key challenges were met(12). C1 [Dahya, Neil] NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Roberts, Eric T.] Flight Hardware Engn Inc, Pasadena, CA 91109 USA. RP Dahya, N (reprint author), NASA, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Neil.T.Dahya@jpl.nasa.gov; EricRobertsFHW@gmail.com NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2975 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201157 ER PT S AU Knight, J Ghandchi, S AF Knight, Jennifer Ghandchi, Saina GP IEEE TI Mars Science Laboratory - Backshell Interface Plate and Parachute Support Structure subsystem SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Mars Science Laboratory is a scientific mission to deliver a rover with ten science instruments to the surface of Mars. In order to accomplish this, a Cruise Stage and Entry Vehicle, which is comprised of an Aeroshell and Descent Stage, are used. The Backshell Interface Plate (BIP) interfaces to the Backshell, the Cruise Stage and the Descent Stage. Also attached to the BIP is the Parachute Support Structure (PSS) which interfaces to both structure and soft goods of the Parachute Deceleration System. The primary function of the BIP and PSS is to anchor all of these major subsystems together and provide the structural load paths necessary to support the launch, entry, mortar fire, and parachute inflation loads. The key challenges for this hardware he in the complex configuration, several unique load cases, multiple load paths, and the magnitude of the loads. This paper will describe the design of the Backshell Interface Plate and Parachute Support Structure as well as the key challenges and how they were met(12). C1 [Knight, Jennifer; Ghandchi, Saina] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Knight, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2981 EP 2986 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201158 ER PT S AU Cook, B Braun, D Hankins, S Koenig, J Moore, D AF Cook, Brant Braun, Dave Hankins, Steve Koenig, John Moore, Don GP IEEE TI Direct drive precision linear actuator for space interferometry mission (SM) Siderostat pointing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB "SIM PlanetQuest will exploit the classical measuring tool of astrometry (interferometry) with unprecedented precision to make dramatic advances in many areas of astronomy and astrophysics." (1) In order to achieve the required pointing precision of SIM, a gimbaled Siderostat (SID) pointing mechanism with coarse and fine stage actuators is being employed. In order to better understand the coarse pointing accuracy, a team of engineers set out to design, build, and test a linear ballscrew actuator that can perform submicron incremental steps for 10 years of continuous operation. Point tracking and low disturbance requirements lead the team to implement a ballscrew actuator with a direct drive DC motor and a piezo brake. By using an off the shelf motor, Hall effect sensor, ballscrew, and glass scale encoder, repeatable 20 nm incremental steps (actuator resolution) over a 120mm range was achieved. The results exceed expectations by a factor of 50 times and prove linear nanometer positioning requires no gears, levers, or hydraulic converters(12). C1 [Cook, Brant; Braun, Dave; Hankins, Steve; Koenig, John; Moore, Don] Jet Prop Lab, Los Angeles, CA 91101 USA. RP Cook, B (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Los Angeles, CA 91101 USA. NR 3 TC 0 Z9 0 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 2987 EP 3000 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201159 ER PT S AU Gradziel, MJ Holgerson, KJ AF Gradziel, Michael J. Holgerson, Kristopher J. GP IEEE TI Mechanisms for lowering tethered payloads: Lessons learned from the Mars Exploration Program SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Compact, lightweight, highly reliable lowering devices capable of paying out tether to lower a payload some number of meters with exacting performance, from a balloon or a parachute or part of a spacecraft, typically appear in systems so unique that there is little historical precedent to build upon when preparing designs. However the NASA Mars Exploration Program has in recent years sent three such lowering devices to the red planet, producing an abundance of lessons learned and three satisfactory - though not flawless - landings. Anomalous drag behavior on the first MER lander, results from tests seeking to find the cause of change in brake drag, basic equations for centrifugal brakes and tapered spool descent mechanisms, tether design, and a lowering device designed for an upcoming Mars landing will be discussed(12). C1 [Gradziel, Michael J.; Holgerson, Kristopher J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gradziel, MJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3001 EP 3020 PG 20 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201160 ER PT S AU Jau, BM AF Jau, Bruno M. GP IEEE TI Mechanical description of the Mars Climate Sounder Instrument SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper introduces the Mars Climate Sounder (MCS) Instrument of the Mars Reconnaissance Orbiter (MRO) spacecraft. The instrument scans the Martian atmosphere almost continuously to systematically acquire weather and climate observations over time. Its primary components are an optical bench that houses dual telescopes With a total of nine channels for visible and infrared sensing, and a two axis gimbal that provides pointing capabilities. Both rotating joints consist of an integrated actuator with a hybrid planetary/harmonic transmission and a twist cap section that enables the electrical wiring to pass through the rotating joint. Micro stepping is used to reduce spacecraft disturbance torques to acceptable levels while driving the stepper motors. To ensure survivability over its four year life span, suitable mechanical components, lubrication, and an active temperature control system were incorporated. Some life test results and lessons learned are provided to serve as design guidelines for actuator parts and flex cables(12). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jau, BM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3021 EP 3028 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321201161 ER PT S AU Kremic, T Anderson, DJ Dankanich, JW AF Kremic, Tibor Anderson, David J. Dankanich, John W. GP IEEE TI NASA's In-Space Propulsion Technology Project overview and mission applicability SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The In-Space Propulsion Technology Project, funded by NASA!s Science Mission Directorate (SMD), is continuing to invest in propulsion technologies that win enable or enhance NASA robotic science missions. This paper provides development status, near-term mission benefits, applicability, and availability of in-space propulsion technologies in the areas of aerocapture, electric propulsion, and advanced chemical thrusters. Aerocapture investments have 1) improved models for: guidance, navigation, and control of blunt body rigid aeroshells, 2) atmospheric models for Earth, Titan, Mars and Venus, and 3) models for aerothermal effects. Investments in electric propulsion technologies have focused on completing the NEXT ion propulsion system, a 0.6-7kW throttle-able gridded ion system. The primary chemical propulsion investment is on a high-temperature storable bi-propellant rocket engine providing higher performance for lower cost. Development status of mid-term technology, the low-cost HiVHAC Hall thruster is also presented. In-space propulsion technologies are applicable, and potentially enabling for flagship destinations currently under evaluation, as well as having broad applicability to future Discovery and New Frontiers mission solicitations. C1 [Kremic, Tibor; Anderson, David J.] NASA, Glenn Res Ctr, ISPT, 21000 Brookpk Rd, Cleveland, OH 44135 USA. [Dankanich, John W.] Gray Res Inc, Cleveland, OH 44135 USA. RP Kremic, T (reprint author), NASA, Glenn Res Ctr, ISPT, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Tibor.Kremic@nasa.gov; David.J.Anderson@nasa.gov; John.Dankanich@nasa.gov FU National Aeronautics and Space Administration (NASA); Science Mission Directorate (SMD) FX The results and findings presented here are based on work funded by the National Aeronautics and Space Administration (NASA), Science Mission Directorate (SMD). The authors acknowledge the technical achievements by the respective NASA and contractor teams and the contributions of the respective technology area project managers. NR 16 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3029 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202001 ER PT S AU Munk, MM Moon, SA AF Munk, Michelle M. Moon, Steven A. GP IEEE TI Aerocapture technology development overview SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper will explain the investment strategy, the role of detailed systems analysis, and the hardware and modeling developments that have resulted from the past 5 years of work under NASA's In-Space Propulsion Program (ISPT) Aerocapture investment area. The organizations that have been funded by ISPT over that time period received awards from a 2002 NASA Research Announcement. They are: Lockheed Martin Space Systems, Applied Research Associates, Inc., Ball Aerospace, NASA's Ames Research Center, and NASA's Langley Research Center. Their accomplishments include improved understanding of entry aerothermal environments, particularly at Titan, demonstration of aerocapture guidance algorithm robustness at multiple bodies, manufacture and test of a 2-meter Carbon-Carbon "hot structure," development and test of evolutionary, high-temperature structural systems with efficient ablative materials, and development of aerothermal sensors that will fly on the Mars Science Laboratory in 2009. Due in large part to this sustained ISPT support for Aerocapture, the technology is ready to be validated in flight.(12). C1 [Munk, Michelle M.] NASA, Langley Res Ctr, Mail Stop 494, Hampton, VA 23681 USA. [Moon, Steven A.] Gray Res Inc, Huntsville, AL 35806 USA. RP Munk, MM (reprint author), NASA, Langley Res Ctr, Mail Stop 494, Hampton, VA 23681 USA. EM Michelle.M.Munk@nasa.gov; Steve.Moon@nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3039 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202002 ER PT S AU Pencil, EJ AF Pencil, Eric J. GP IEEE TI An overview of recent developments in electric propulsion for NASA science mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The primary source of electric propulsion development throughout NASA is managed by the In-Space Propulsion Technology Project at the NASA Glenn Research Center for the Science Mission Directorate. The objective of the Electric Propulsion project area is to develop near-term electric propulsion technology to enhance or enable science mission while minimizing risk and cost to the end user. Major hardware tasks include developing NASA's Evolutionary Xenon Thruster (NEXT), developing a long-life High Voltage Hall Accelerator (HIVHAC), developing an advanced feed system, and developing cross-platform components. The objective of the NEXT task is to advance next generation ion propulsion technology readiness. The NEXT system consists of a high-performance, 7-kW ion thruster; a high-efficiency, 7-kW power processor unit (PPU); a highly flexible advanced xenon propellant management system (PMS); a lightweight engine gimbal; and key elements of a digital control interface unit (DCIU) including software algorithms. This design approach was selected to provide future NASA science missions with the greatest value in mission performance benefit at a low total development cost. The objective of the HIVHAC task is to advance the Hall thruster technology readiness for science mission applications. The task seeks to increase specific impulse, throttle-ability and lifetime to make Hall propulsion systems applicable to deep space science missions. The primary application focus for the resulting Hall propulsion system would be cost-capped missions, such as competitively-selected, Discovery-class missions. The objective of the advanced xenon feed system task is to demonstrate novel manufacturing techniques that will significantly reduce mass, volume, and footprint size of xenon feed systems over conventional feed systems. The task has focused on the development of a flow control module, which consists of a three-channel flow system based on a piezo-electrically actuated valve concept. Component standardization and simplification are being investigated through the Standard Architecture task to reduce first user costs for implementing electric propulsion systems. Progress on current hardware development, recent test activities and future plans are discussed.(12). C1 [Pencil, Eric J.] NASA, Glenn Res Ctr, In Space Prop Technol Off, Cleveland, OH 44135 USA. RP Pencil, EJ (reprint author), NASA, Glenn Res Ctr, In Space Prop Technol Off, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 21 TC 0 Z9 0 U1 3 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3046 EP 3054 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202003 ER PT S AU Benson, SW Patterson, MJ AF Benson, Scott W. Patterson, Michael J. GP IEEE TI Technology readiness of the NEXT ion propulsion system SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system has been in advanced technology development under the NASA In-Space Propulsion Technology project. The highest fidelity hardware planned has now been completed by the government/industry team, including: a flight prototype model (PM) thruster, an engineering model (EM) power processing unit, EM propellant management assemblies, a breadboard gimbal, and control unit simulators. Subsystem and system level technology validation testing is in progress. To achieve the objective Technology Readiness Level 6, environmental testing is being conducted to qualification levels in ground facilities simulating the space environment. Additional tests have been conducted to characterize the performance range and life capability of the NEXT thruster. This paper presents the status and results of technology validation testing accomplished to date, the validated subsystem and system capabilities, and the plans for completion of this phase of NEXT development. The next round of competed planetary science mission announcements of opportunity, and directed mission decisions, are anticipated to occur in 2008 and 2009. Progress to date, and the success of on-going technology validation, indicate that the NEXT ion propulsion system will be a primary candidate for mission consideration in these upcoming opportunities.(12). C1 [Benson, Scott W.; Patterson, Michael J.] NASA, Glenn Res Ctr, NEXT Ion Prop Syst Technol Dev Project, 21000 Brookpk Rd, Cleveland, OH 44135 USA. RP Benson, SW (reprint author), NASA, Glenn Res Ctr, NEXT Ion Prop Syst Technol Dev Project, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Scott.W.Benson@nasa.gov; Michael.J.Patterson@nasa.gov NR 29 TC 0 Z9 0 U1 2 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3055 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202004 ER PT S AU Liou, L AF Liou, Larry GP IEEE TI Advanced chemical propulsion for science missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The advanced chemical propulsion technology area of NASA's In-Space Technology Project is investing in systems and components for increased performance and reduced cost of chemical propulsion technologies applicable to near-term science missions. Presently the primary investment in the advanced chemical propulsion technology area is in the AMBR high temperature storable bipropellant rocket engine. Scheduled to be available for flight development starting in year 2008, AMBR engine shows a 60 kg payload gain in an analysis for the Titan-Enceladus orbiter mission and a 33% manufacturing cost reduction over its baseline, state-of-the-art counterpart. Other technologies invested include the reliable lightweight tanks for propellant and the precision propellant management and mixture ratio control. Both technologies show significant mission benefit, can be applied to any liquid propulsion system, and upon completion of the efforts described in this paper, are at least in parts ready for flight infusion. Details of the technologies are discussed.(1 2). C1 NASA, John H Glenn Res Ctr, In Space Prop Technol Project Off, Adv Chem Prop Area, Cleveland, OH 44135 USA. RP Liou, L (reprint author), NASA, John H Glenn Res Ctr, In Space Prop Technol Project Off, Adv Chem Prop Area, Mail Stop 142-2,21000 Brook Pk Rd, Cleveland, OH 44135 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3072 EP 3081 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202006 ER PT S AU Joo, S Ippolito, C Al-Ali, K Yeh, YH AF Joo, Sungmoon Ippolito, Corey Al-Ali, Khalid Yeh, Yoo-Hsiu GP IEEE TI Vision aided inertial navigation with measurement delay for fixed-wing unmanned aerial vehicle landing SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID OPTICAL-FLOW AB Usually, standard inertial navigation unit (INU) with global positioning system (GPS) provides relatively poor accuracy in altitude estimation, while autonomous landing of unmanned aerial vehicles (UAVs) requires accurate position estimation. In this paper, a UAV navigation system with aid from an external camera for landing is investigated. This paper presents: (i) a sensor fusion algorithm for passive monocular vision and INU based on the Extended Kalman Filter (EKF) considering measurement delay to improve the accuracy of position estimates, and (ii) a robust object-detection vision algorithm using optical flow. Pilot controlled landing experiments on a NASA UAV platform and the filter simulations validate the feasibility and performance of the proposed approach(12). C1 [Joo, Sungmoon] Stanford Univ, Dept Aeronaut & Astronaut, Aerosp Robot Lab, Stanford, CA 94305 USA. [Ippolito, Corey] NASA, Ames Res Ctr, Adv Control & Evolable Syst Grp, Moffett Field, CA 94035 USA. [Al-Ali, Khalid; Yeh, Yoo-Hsiu] Carnegie Mellon Univ, Carnegie Mellon Innovat Lab, Moffett Field, CA 94035 USA. RP Joo, S (reprint author), Stanford Univ, Dept Aeronaut & Astronaut, Aerosp Robot Lab, Stanford, CA 94305 USA. EM joosm@stanford.edu; cippolito@mail.arc.nasa.gov; alali@cmu.edu; yoohsiu.yeh@west.cmu.edu FU NASA [NNA05CV37A] FX This work was supported in part by NASA Grant NNA05CV37A. The authors wish to thank Mark Sumich from NASA ARC, and the student interns, Matt Walliser and Ace Shelander, for providing support to this research. NR 18 TC 0 Z9 0 U1 4 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3152 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202014 ER PT S AU Lindvall, M Ackermann, C Stratton, WC Sibol, DE Ray, A Yonkwa, L Kresser, J Godfrey, S Knodel, J AF Lindvall, Mikael Ackermann, Chris Stratton, William C. Sibol, Deane E. Ray, Arnab Yonkwa, Lyly Kresser, Jan Godfrey, Sally Knodel, Jens GP IEEE TI Using sequence diagrams to detect communication problems between systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Many software systems are evolving complex system of systems (SoS) for which inter-system communication is both mission-critical and error-prone. Such communication problems ideally would be detected before deployment. In a NASA-supported Software Assurance Research Program (SARP) project, we are researching a new approach addressing such problems. In this paper, we show that problems in the communication between two systems can be detected by using sequence diagrams to model the planned communication and by comparing the planned sequence to the actual sequence. We identify different kinds of problems that can be addressed by modeling the planned sequence using different level of abstractions. C1 [Lindvall, Mikael; Ackermann, Chris] Fraunhofer Ctr Expt Software Engn Maryland FC MD, 4321 Hartwick Rd,Suite 500, College Pk, MD 20740 USA. [Stratton, William C.; Sibol, Deane E.] Johns Hopkins Univ, Appl Phys Lab, Dept Ground Appl Grp, Laurel, MD 20723 USA. [Ray, Arnab; Yonkwa, Lyly; Kresser, Jan] Johns Hopkins Univ, FC MD, Laurel, MD 20723 USA. [Godfrey, Sally] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. [Knodel, Jens] Univ Kaiserslautern, IESE, D-67663 Kaiserslautern, Germany. RP Lindvall, M (reprint author), Fraunhofer Ctr Expt Software Engn Maryland FC MD, 4321 Hartwick Rd,Suite 500, College Pk, MD 20740 USA. EM mlindvall@fc-md.umd.edu; cackermann@fc-md.umd.edu; Wilham.Stratton@jhuapl.edu; Deane.Sibol@jhuapl.edu; array@fc-md.umd.edu; lyonkwa@fc-md.umd.edu; jkresser@fc-md.umd.edu; Sara.H.Godfrey@nasa.gov; Jens.Knodel@iese.fraunhofer.de FU NASA IV&V Center's Software Assurance Research Program; NSF [CCF0438933]; German Ministry of Education and Research (BMBF) [01 IS F14] FX The authors acknowledge support form the NASA IV&V Center's Software Assurance Research Program and, from NSF grant CCF0438933, "Flexible High Quality Design for Software." This work was partially performed as part of the ArQuE (Architecture-Centric Quality Engineering) project, which is funded by the German Ministry of Education and Research (BMBF) under grant number 01 IS F14.The authors would like to thank Dr. Mike Hinchey for supporting this work, Mr. Dharmalingam Ganesan and Mr. Jorg Weinmann for their work on the dynamic analysis feature, and Ms. Myma Regardie for proof reading and editing this paper. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3302 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202028 ER PT S AU Mehlitz, PC AF Mehlitz, Peter C. GP IEEE TI Trust your model - Verifying aerospace system models with Java (TM) Pathfinder SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Model Driven Development (NOD) is rapidly becoming a mainstream practice for the development of complex aerospace systems. UML has emerged as the de facto standard for modeling languages, supporting a wide range of modeling aspects and refinement levels. As a consequence, models can easily become too complex for manual verification and simple static analysis(12). This paper describes an approach to using the Java (TM) Pathfmder (JPF) software model checker to systematically verify UML state charts. While state machines in general are amenable to model checking, embedded actions and guards in UML state charts are not, since they require execution and analysis of a full programming language to cover the whole model behavior. Many UML development systems can produce code from diagrams, but this code is usually aimed at production systems, and is not suitable for software model checkers. Our approach is based on a specific translation scheme from UML state charts into Java code that (a) is highly readable, (b) shows close correspondence between diagram and program, (c) provides a 1:1 mapping between model and program states, and (d) imposes no restrictions about aspects and actions that can be modeled. We have demonstrated scalability and efficiency of this approach on hierarchical state charts with up to 1000 states, including verification of incomplete models by means of guided model checking. This paper provides an overview of the method based on an exemplary spacecraft model. C1 NASA, Ames Res Ctr, Perot Syst Govt Serv, Moffett Field, CA 94035 USA. RP Mehlitz, PC (reprint author), NASA, Ames Res Ctr, Perot Syst Govt Serv, M-S 269-2, Moffett Field, CA 94035 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3321 EP 3331 PG 11 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202030 ER PT S AU Brat, G Gheorghiu, M Giannakopoulou, D Pasareanu, C AF Brat, G. Gheorghiu, M. Giannakopoulou, D. Pasareanu, C. GP IEEE TI Verification of plans and procedures SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Procedures and plans are used across NASA missions. For example, astronaut activities on the International Space Station are regulated by procedures which are uploaded from the ground. It is critical that these procedures are verified and validated before being executed by astronauts. This paper describes how we are applying advanced formal verification techniques, such as model checking, to plans and procedures expressed in semantically well-defined languages such as PRL and PLEXIL1,2,3. C1 [Brat, G.; Gheorghiu, M.; Giannakopoulou, D.; Pasareanu, C.] NASA, Ames Res Ctr, USRA RIACS, Perot Syst Govr Serv, Moffett Field, CA 94035 USA. RP Brat, G (reprint author), NASA, Ames Res Ctr, USRA RIACS, Perot Syst Govr Serv, MS 269-2, Moffett Field, CA 94035 USA. NR 8 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3332 EP 3339 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202031 ER PT S AU Denney, E Trac, S AF Denney, Ewen Trac, Steven GP IEEE TI A software safety certification tool for automatically generated Guidance, Navigation and Control code SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Model-based(1,2) design and automated code generation are being used increasingly at NASA. Many NASA projects now use MathWorks Simulink and Real-Time Workshop for at least some of their modeling and code development. The trend is to move beyond simulation and prototyping to actual flight code, particularly in the Guidance, Navigation, and Control domain. However, there are substantial obstacles to more widespread adoption of code generators in such safety-critical domains. Since code generators are typically not qualified, there is no guarantee that their output is correct, and consequently the generated code still needs to be fully tested and certified. Moreover, the regeneration of code can require complete recertification, which offsets many of the advantages of using a generator. Indeed, manual review of autocode can be more challenging than for hand-written code. Since the direct V&V of code generators is too laborious and complicated due to their complex (and often proprietary) nature, we have developed a generator plug-in to support the subsequent certification of the code that is generated. Specifically, the AutoCert tool supports certification by formally verifying that the generated code is free of different safety violations, by constructing an independently verifiable certificate, and by explaining its analysis in a textual form suitable for code reviews. This enables missions to obtain assurance about the safety and reliability of the code without excessive manual V&V effort and, as a consequence, increases the acceptance of code generators in safety-critical contexts. The generation of explicit certificates and textual reports is particularly well-suited to supporting independent V&V. The key technical idea of our approach is to exploit the idiomatic nature of auto-generated code in order to automatically infer logical annotations. These allow the automatic formal verification of the safety properties without requiring access to the internals of the code generator. The approach is independent of the particular generator used but is currently being adapted to code generated using MathWorks Real-Time Workshop, an automatic code generator that translates from Simulink/Stateflow models into embedded C code. C1 [Denney, Ewen] NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. [Trac, Steven] Univ Miami, Coral Gables, FL 33146 USA. RP Denney, E (reprint author), NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. EM edenney@email.arc.nasa.gov; strac@mail.cs.miami.edu NR 12 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3347 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202033 ER PT S AU Thompson, S Brat, G AF Thompson, S. Brat, G. GP IEEE TI Verification of C++ flight software with the MCP model checker SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Constellation project at NASA calls for designing a Crew Exploration Vehicle (Orion, also called CEV) and Cargo Launch Vehicle (Ares, also called CLV). Both projects will rely on newly designed flight control software. The verification of these C++ flight codes is critical, especially for Orion, since human life will be at stake. There exist some commercial tools for the verification of C++ code. However, none of the commercially available tools does a good job a finding bugs dealing with concurrency. Yet both software for Orion and Ares are expected to be multi-threaded. With this work we are proposing to address the issue by developing a suite of tools that can be used to verify C++ code. Our tools will range from a static analyzer (based on abstract interpretation like C Global Surveyor) to a model checker (MCP, which we present in this paper) including a symbolic execution engine for test case generation (TPGEN). This paper focuses on MCP and its application to Aerospace software(1). C1 [Thompson, S.; Brat, G.] NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. RP Thompson, S (reprint author), NASA, Ames Res Ctr, USRA RIACS, MS 269-2, Moffett Field, CA 94035 USA. EM thompson@email.arc.nasa.gov; brat@email.arc.nasa.gov NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3358 EP 3366 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202034 ER PT S AU White, AL AF White, Allan L. GP IEEE TI Efficient simulation for testing loss of separation algorithms SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Given increased air traffic and the possible use of autonomous vehicles, there is interest in the verification of separation algorithms. Because of the complexity of the environment and the presence of perturbations, a candidate approach is simulation and Monte Carlo. There are several desirable properties of the simulation: realism, portability, transparency, and efficiency. This paper is an initial effort using MATLAB to study a separation algorithm. An original separation algorithm was developed to make this project independent of any other effort. The algorithms and program were effective enough and efficient enough that the project will proceed(1,2). C1 NASA Langley, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA Langley, Hampton, VA 23681 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3385 EP 3393 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202037 ER PT S AU Powell, MW Crockett, TM Fox, JM Joswig, J Norris, JS Shams, K Torres, RJ AF Powell, Mark W. Crockett, Thomas M. Fox, Jason M. Joswig, Joseph Norris, Jeffrey S. Shams, Khawaja Torres, Recaredo Jay GP IEEE TI Delivering images for Mars rover science planning SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Mars rover images provide essential context for planning science activities. This work describes a method for delivering Mars rover images to operations planners that is highly efficient and scalable. Experimental results of various image compression strategies applied to rover images are given. Next, an adaptive level-of-detail tile-based delivery methodology for images is presented. With a tile-aware image browsing application, images of virtually limitless size may be distributed to participating scientists with great efficiency and thus provide a common collaborative context. This work also describes advances in mosaicking rover images in support of operations planning(12). C1 [Powell, Mark W.; Crockett, Thomas M.; Fox, Jason M.; Joswig, Joseph; Norris, Jeffrey S.; Shams, Khawaja; Torres, Recaredo Jay] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Powell, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3394 EP 3405 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202038 ER PT S AU Knight, CD Malin, JT AF Knight, Christopher D. Malin, Jane T. GP IEEE TI Contextualized search and faceted browsing of heterogeneous ISS mission operations data SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper(12) details a full-text search interface developed to support mission operators to quickly search across multiple databases simultaneously and allow for search result refinement using a faceted user interface. By leveraging the contextualized NETMARK[1] eXtensible DataBase (XDB), this search interface automatically infers categories for facets and allows users to select one or more category for each facet to narrow the results to only display those that meet all of the selected facet categories. C1 [Knight, Christopher D.] NASA, Ames Res Ctr, Mail Stop 269-4, Moffett Field, CA 94035 USA. [Malin, Jane T.] NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Knight, CD (reprint author), NASA, Ames Res Ctr, Mail Stop 269-4, Moffett Field, CA 94035 USA. EM Christopher.D.Knight@nasa.gov; jane.t.malin@nasa.gov NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3406 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202039 ER PT S AU Gurram, MM Knight, CD AF Gurram, Mohana M. Knight, Christopher D. GP IEEE TI Functional hierarchical search results data analysis SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB (1)NASA Ames, in collaboration with JSC ISS MOD, has been developing novel systems for searching across multiple heterogeneous data systems in order to facilitate rapid retrieval of relevant information for flight controllers on console and in their off-console duties. Traditional data mining techniques to identify document similarity rely upon brute-force O(n(2)) cosine similarity of vectors representing text contained in the documents--an expensive and time-consuming operation that becomes unfeasible on large data sets such as those in use by the Shuttle and Station programs at NASA. This paper details a technique developed as part of this activity to identify documents similar to documents relevant and of interest to the user by leveraging the prior search results to produce a weighted graph of document relationships based upon search terms. This paper details the algorithms used, the user interface prototypes developed to evaluate the usefulness of similarity to the browsing activities of users, and the evaluation of the accuracy of this technique as compared with traditional data mining techniques. C1 [Gurram, Mohana M.] NASA, Ames Res Ctr, Res Inst Adv Comp Sci, Univ Space Res Assoc, Mailstop 269-1, Moffett Field, CA 94035 USA. [Knight, Christopher D.] NASA, Ames Res Ctr, Moffett Field, CA 95050 USA. RP Gurram, MM (reprint author), NASA, Ames Res Ctr, Res Inst Adv Comp Sci, Univ Space Res Assoc, Mailstop 269-1, Moffett Field, CA 94035 USA. EM mgurram@email.arc.nasa.gov; Christopher.D.Knight@nasa.gov FU NASA [NCC2-1426, NNA07BB97C] FX U.S. Government work not protected by U.S. copyright, based on work supported by NASA under awards NCC2-1426 and NNA07BB97C. NR 8 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3414 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202040 ER PT S AU Leucht, KW Semmel, GS AF Leucht, Kurt W. Semmel, Glenn S. GP IEEE TI Automated translation of safety critical application software specifications into PLC ladder logic SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The numerous benefits of automatic application code generation are widely accepted within the software engineering community. A few of these benefits include raising the abstraction level of application programming, shorter product development time, lower maintenance costs, and increased code quality and consistency. Surprisingly, code generation concepts have not yet found wide acceptance and use in the field of programmable logic controller (PLC) software development. Software engineers at the NASA Kennedy Space Center (KSC) recognized the need for PLC code generation while developing their new ground checkout and launch processing system. They developed a process and a prototype software tool that automatically translates a high-level representation or specification of safety critical application software into ladder logic that executes on a PLC. This process and tool are expected to increase the reliability of the PLC code over that which is written manually, and may even lower life-cycle costs and shorten the development schedule of the new control system at KSC. This paper examines the problem domain and discusses the process and software tool that were prototyped by the KSC software engineers(1,2). C1 [Leucht, Kurt W.; Semmel, Glenn S.] NASA, Engn Dev Directorate, Applicat Simulat & Support Scftware Branch, Kennedy Space Ctr, FL 32899 USA. RP Leucht, KW (reprint author), NASA, Engn Dev Directorate, Applicat Simulat & Support Scftware Branch, Kennedy Space Ctr, FL 32899 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3447 EP 3460 PG 14 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202044 ER PT S AU James, ML Zima, HP AF James, Mark L. Zima, Hans P. GP IEEE TI An introspection framework for fault tolerance in support of autonomous space systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper describes a software system designed for the support of future autonomous space missions by providing an infrastructure for runtime monitoring, analysis, and feedback. The objective of this research is to make mission software executing on parallel on-board architectures fault tolerant through an introspection mechanism that provides automatic recovery minimizing the loss of function and data. Such architectures are essential for future JPL missions because of their increased need for autonomy along with enhanced on-board computational capabilities while in deep space or time-critical situations. The standard framework for introspection described in this paper integrates well with existing flight software architectures and can serve as an enabling technology for the support of such systems. Furthermore, it separates the introspection capability from applications and the underlying system, providing a generic framework that can be also applied to a broad range of problems beyond fault tolerance, such as behavior analysis, intrusion detection, performance tuning, and power management(12). C1 [James, Mark L.; Zima, Hans P.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP James, ML (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Mark.James@JPL.NASA.GOV; Zima@JPL.NASA.GOV NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3510 EP 3517 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202049 ER PT S AU Bennett, M Dvorak, D Hutcherson, J Ingham, M Rasmussen, R Wagner, D AF Bennett, Matthew Dvorak, Daniel Hutcherson, Joseph Ingham, Michel Rasmussen, Robert Wagner, David GP IEEE TI An architectural pattern for goal-based control SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Time-based command sequencing is the traditional paradigm for control of spacecraft and rovers in NASA's robotic missions, but this paradigm has been increasingly strained to accommodate today's missions. Goal-based control is a new paradigm that supports time-driven and event-driven operation in a more natural way and permits a melding of sequencing and fault protection into a single control paradigm. This paper describes one approach to goal-based control as an architectural pattern in terms of purpose, motivation, structure, applicability, and consequences. This paper is intended to help flight and ground software engineers understand the new paradigm and how it compares to time-based sequencing.(12). C1 [Bennett, Matthew; Dvorak, Daniel; Hutcherson, Joseph; Ingham, Michel; Rasmussen, Robert; Wagner, David] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bennett, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3530 EP 3546 PG 17 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202051 ER PT S AU Mindock, J Watney, G AF Mindock, Jennifer Watney, Garth GP IEEE TI Integrating system and software engineering through modeling SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB System engineers(1,2) who are responsible for capturing the formal requirements of a system typically have relied on text-based tools and free-form diagrams, otherwise known as "shall statements" and "PowerPoint engineering". In our work with the Space Interferometry Mission (SIM) at NASA's Jet Propulsion Laboratory, we found the need to unambiguously represent behaviors and interfaces using common language and terminology across multiple project elements, for example, throughout different levels of system engineering and among system, software, and controls engineering. The system engineers adopted portions of the Unified Modeling Language (UML) [1] as a means to effectively communicate interfaces and desired system behaviors. UML sequence diagrams were used to capture scenarios and provide context for and understanding of the intent of the typical "shall statements". UML Statechart diagrams were used to capture dynamic behavior. In practice, the system and software engineers would iterate together on these models. Iterating on models proved to be a highly effective method of "fleshing-in" loosely worded and ambiguous requirements. Requirements have typically been difficult for the software engineer to implement without understanding the intent behind the requirements. Through the process of modeling, we found that system and software engineers effectively communicated interfaces and behavior. Modeling provided other benefits as well, notably, the ability to auto-generate portions of the flight code from these models and to apply formal methods to prove various correctness properties regarding the model. In this paper, we will describe in further detail how system engineers used modeling as an effective communication tool to capture requirements, their context, and the ensuing design throughout multiple levels of the system and within a subsystem. This increased software engineers' understanding of and insight into the system, making the software design process more efficient. In addition, we win describe how software engineers leveraged the models to improve the quality and reduce the cost of the final software product. C1 [Mindock, Jennifer; Watney, Garth] CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RP Mindock, J (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3547 EP 3558 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202052 ER PT S AU Oh, JMC Watney, GJ Benowitz, EG AF Oh, Jane M. C. Watney, Garth J. Benowitz, Edward G. GP IEEE TI Software assurance for model-based design SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Within(1,2) JPL and NASA, the emergence of model-based design will reformulate the design process. Simultaneously, the mission-critical role of software is increasing. Thus, the nature of software assurance must change accordingly. This paper examines the experience of using model-based design in the context of development of mission flight software and also covers how software assurance practices are being adapted to work with this approach. In the model-based development paradigm, novelty stems from the fact that many of the artifacts are in machine manipulable representations, not simply paragraphs of textual descriptions or drawings intended purely for human viewing. Furthermore, using tools that support the model-based paradigm allows automatic code generation to be employed, yielding significant portions of machine-generated source code as significant parts of the development efforts. C1 [Oh, Jane M. C.; Watney, Garth J.; Benowitz, Edward G.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Oh, JMC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Jane.C.Oh@jpl.nasa.gov; Garth.J.Watney@jpl.nasa.gov; Edward.G.Benowitz@jpl.nasa.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3559 EP 3564 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202053 ER PT S AU Mazer, AS Loring, SM AF Mazer, Alan S. Loring, Scott M. GP IEEE TI Automated testing of science instrument flight software SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper(12) describes an approach to automated testing of science instrument flight software using scripted commanding, telemetry capture, and intelligent telemetry verification. The most difficult piece of this approach, telemetry verification, is accomplished with a JPL-developed software package, HKCheck, which takes user-defined packet formats, error conditions, and goals, and verifies that binary telemetry meets the specified conditions. Packet formats are defined using an ASCII file, easily created in any text editor. Test-specific and context-specific error conditions are expressed using a simple C-like notation, enabling large amounts of-telemetry from normal flight operation or system testing to be rapidly scanned for anomalous telemetry. Goals, like waypoints, are similarly expressed in simple notation, and allow telemetry analysts or test conductors to look for specific events in the telemetry stream. The power and flexibility of the HKCheck error and goal specification language enables context-dependent analysis of telemetry, and rapid, repeatable analysis of test results, encouraging more frequent testing, and reducing the risk of human error in test analysis. Use of HKCheck on Mars Climate Sounder enabled full regression testing of flight software every month or two, rather than just on major deliveries, giving developers confidence that software was working correctly and uncovering potential bugs earlier in the development cycle than standard methods allow. It has since been used, with extensions, on other flight projects as well. C1 [Mazer, Alan S.; Loring, Scott M.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mazer, AS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 168-514, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3565 EP 3576 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202054 ER PT S AU Khalak, A Goebel, K AF Khalak, Asif Goebel, Kai GP IEEE TI Real-time probabilistic forecasting of wear degradation using a macro-scale physical model SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Friction and wear processes have their origins in the surface interactions between solid materials with many dynamically important details at the microscale. These details such as the structure of surface roughness, etc. may be framed in terms of macro parameters, but there is necessarily a degree of abstraction and uncertainty in this description. As such, wear models tend to have a significant degree of uncertainty. Moreover, since the physics of contact wear as wen as the relevant parameters are uncertain, the damage may be multi-modal and tends to take non-Gaussian Forms. C1 [Khalak, Asif] Sci Monitoring Inc, Manager Res & Technol, Scottsdale, AZ 85258 USA. [Goebel, Kai] NASA Ames Res Ctr, Prognost Ctr Excellence, Moffett Field, CA USA. RP Khalak, A (reprint author), Sci Monitoring Inc, Manager Res & Technol, Scottsdale, AZ 85258 USA. EM asif@scientificmonitoring.com; kai.f.goebel@nasa.gov FU NASA STTR [NNX07CA35P] FX This work was partially supported by NASA STTR Contact NNX07CA35P, Technical Monitor, Dr. Dogan Timucin. The authors would like to thank Mr. Hoang Van Tran for developing the flight control model and assisting in the interpretation of the model NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3899 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202085 ER PT S AU Saha, B Goebel, K AF Saha, Bhaskar Goebel, Kai GP IEEE TI Uncertainty management for diagnostics and prognostics of batteries using Bayesian techniques SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID HYBRID-ELECTRIC VEHICLES; LEAD-ACID-BATTERIES; STATE-OF-CHARGE; HEALTH AB Uncertainty management has always been the key hurdle faced by diagnostics and prognostics algorithms. A Bayesian treatment of this problem provides an elegant and theoretically sound approach to the modem Condition-Based Maintenance (CBM)/Prognostic Health Management (PHM) paradigm. The application of the Bayesian techniques to regression and classification in the form of Relevance Vector Machine (RVM), and to state estimation as in Particle Filters (PF), provides a powerful tool to integrate the diagnosis and prognosis of battery health. The RVK which is a Bayesian treatment of the Support Vector Machine (SVM), is used for model identification, while the PF framework uses the learnt model, statistical estimates of noise and anticipated operational conditions to provide estimates of remaining useful life (RUL) in the form of a probability density function (PDF). This type of prognostics generates a significant value addition to the management of any operation involving electrical systems. C1 [Saha, Bhaskar] Georgia Inst Technol, Sch Elect & Comp Engn, 777 Atlantic Dr NW, Atlanta, GA 30332 USA. [Goebel, Kai] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Saha, B (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, 777 Atlantic Dr NW, Atlanta, GA 30332 USA. EM bsaha@ece.gatech.edu; goebel@email.arc.nasa.gov NR 16 TC 0 Z9 0 U1 0 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 3925 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202088 ER PT S AU Pisanich, G Bajwa, A Sanderfer, D AF Pisanich, Greg Bajwa, Anupa Sanderfer, Dwight GP IEEE TI An Abort Failure Detection, Notification, & Response System: Overview of an ISHM development process SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Timely detection and response to catastrophic events during the launch and ascent phase of a launch system is of paramount importance to crew safety. This requires an abort system capable of detecting and confirming conditions that may lead to catastrophic failure, notifying the crew of the problem, and responding in time to allow the crew to escape safely. The development process for an Abort Failure Detection, Notification, and Response System is described. The process follows an iterative approach that first analyzes the vehicle design and identifies potential abort conditions. Those conditions are then characterized through modeling and simulation, with the results being used to identify required sensors and develop algorithms capable of detecting and responding to abort anomalies that could jeopardize the crew and mission. This process can be applied in the development of future crewed vehicles and other complex vehicle systems(1,2). C1 [Pisanich, Greg] NASA, Ames Res Ctr, Perot Syst Govt Serv, MS 269-3, Moffett Field, CA 94035 USA. [Bajwa, Anupa] Univ Calif, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Sanderfer, Dwight] NASA, Ames Res Ctr, Div Intelligent Syst, Moffett Field, CA 94035 USA. NASA, George C Marshall Space Flight Ctr, EV Adv Sensor & Syst Hlth Management, Huntsville, AL 35812 USA. RP Pisanich, G (reprint author), NASA, Ames Res Ctr, Perot Syst Govt Serv, MS 269-3, Moffett Field, CA 94035 USA. EM Gregory.M.Pisanich@nasa.gov; Anupa.R.Bajwa@nasa.gov; Dwight.T.Sanderfer@nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4044 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202100 ER PT S AU Luchinsky, DG Osipov, VV Smelyanskiy, VN Timucin, DA Uckun, S AF Luchinsky, Dmitry G. Osipov, Vyatcheslav V. Smelyanskiy, Vadim N. Timucin, Dogan A. Uckun, Serdar GP IEEE TI Model based IVHM system for the solid rocket booster SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB We report progress in the development of a model-based hybrid probabilistic approach to an on-board IVHM for solid rocket boosters (SRBs) that can accommodate the abrupt changes of the model parameters in various nonlinear dynamical off-nominal regimes. The work is related to the ORION mission program. Specifically, a case breach fault for SRBs is considered that takes into account burning a hole through the rocket case, as wen as ablation of the nozzle throat under the action of hot gas flow. A high-fidelity model (HIM) of the fault is developed in FLUENT in cylindrical symmetry. The results of the FLUENT simulations are shown to be in good agreement with quasi-stationary approximation and analytical solution of a system of one-dimensional partial differential equations (PDEs) for the gas flow in the combustion chamber and in the hole through the rocket case. The low-dimensional performance model (LDPM) of the fault is derived by integrating a set of one-dimensional PDEs along the axis of the rocket. The LDPM is used to build a model-based fault diagnostic and prognostic (FD&P) algorithm for the case breach fault. In particular, two algorithms are introduced. The first algorithm is based on the self-consistent algorithm that solves the LDPM in a quasi-adiabatic approximation, when the pressure and density follow adiabatically dynamics of the propellant burning, melting and burning of the metal case, ablation and erosion of nozzle and insulator. The second algorithm is based on the dynamical inference method [1]-[3] of the system of stochastic differential equations of the LDPM. The parameters of the HFM model and of the LDPM are tuned to reproduce the results of recent experiments of the rocket firing with the case breach fault in the forward closure. The FD&P is then applied to illustrate real-time diagnostics of the model parameters and prognostics of the SRB internal ballistics. All the algorithms discussed in this paper were verified using experimental data as will be discussed elsewhere. The accuracy of the algorithm and the possibility of its application to FD&P for other SRB fault modes are discussed. C1 [Luchinsky, Dmitry G.] NASA, Ames Res Ctr, Computat Sci Div, Phys Modeling Grp, MS 269-3, Moffett Field, CA 94035 USA. [Smelyanskiy, Vadim N.; Timucin, Dogan A.; Uckun, Serdar] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Luchinsky, DG (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Phys Modeling Grp, MS 269-3, Moffett Field, CA 94035 USA. EM Vadim.N.Smelyanskiy@nasa.gov RI Luchinsky, Dmitry/N-4177-2014 NR 30 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4054 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202101 ER PT S AU Schwabacher, M Waterman, R AF Schwabacher, Mark Waterman, Robert GP IEEE TI Pre-launch diagnostics for launch vehicles SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper discusses the opportunities for automating pre-launch fault detection and diagnostics for launch vehicles, by using ground-based computers to analyze data obtained from the pre-launch umbilical during integrated test and launch countdown operations in near-real time. Automation will improve the time to diagnose and isolate failures, which is critical for planned space missions that require multiple coordinated launches. The paper describes a prototype diagnostic system that we are currently developing for Ares I-X and the foundation that will be developed along with the prototype that will lead to certification of a diagnostic system. The prototype diagnostic system will focus on monitoring and diagnosing the Arcs I-X first-stage thrust-vector control system and solid rocket motor during pre-launch activities at Kennedy Space Center. It will analyze data from existing sensors using rule-based, model-based, and data-driven algorithms. C1 [Schwabacher, Mark] NASA, Ames Res Ctr, Mail Stop 269-3, Moffett Field, CA 94035 USA. [Waterman, Robert] NASA, John F Kennedy Space Ctr, Kennedy Space Ctr, FL 32899 USA. RP Schwabacher, M (reprint author), NASA, Ames Res Ctr, Mail Stop 269-3, Moffett Field, CA 94035 USA. EM mark.a.schwabacher@nasa.gov; robert.d.waterman@nasa.gov NR 18 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4069 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202102 ER PT S AU Iverson, DL AF Iverson, David L. GP IEEE TI System health monitoring for space mission operations SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Many spacecraft provide an abundance of system status telemetry that is monitored in real time by ground personnel and archived to allow for further analysis. In the flight control room, controllers typically monitor these values using text or graphical displays that incorporate individual parameter limit checking or simple trend analysis. Recent developments in data mining techniques for anomaly detection make it possible to use the wealth of archived system data to produce more sophisticated system health monitoring applications. These "data driven" applications are capable of characterizing and monitoring interactions between multiple parameters and can complement existing practice to provide valuable decision support for mission controllers. Data driven software tools have been successfully applied to mission operations for both the Space Shuttle and the International Space Station. These tools have been applied to engineering analysis of spacecraft data to detect unusual events in the data, and to real-time system health monitoring in the flight control room. Augmenting traditional mission control software with advanced monitoring tools can provide controllers with greater insight into the health and performance of the space systems under their watch. Adding heuristic rule based methods that encode system knowledge obtained from seasoned mission controllers can also be helpful to less experienced personnel. We will describe how such techniques have been applied to NASA mission control operations and discuss plans for future mission control system health monitoring software systems.(1,2). C1 NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. RP Iverson, DL (reprint author), NASA, Ames Res Ctr, Intelligent Syst Div, Mail Stop 269-4, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4077 EP 4084 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202103 ER PT S AU Kurien, J R-Moreno, MD AF Kurien, James R-Moreno, Maria Dolores GP IEEE TI Costs and benefits of model-based diagnosis SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Over the past 20 years, there has been much work in the area of model-based diagnosis (MBD). By this we mean diagnosis systems arising from Computer Science or Artificial Intelligence approaches where a generic software engine is developed to address a large class of diagnosis problems [1], [2]. Later, models are created to apply the engine to a specific problem. These techniques are very attractive, suggesting a vision of machines that repair themselves, reduced costs for all kinds of endeavors, spacecraft that continue their missions even when failing, and so on. This promise inspired a broad range of activity, including our involvement over several years in flying the Livingstone and Livingstone 2 on-board model-based diagnosis and recovery systems as experiments on two spacecraft [3], [4], [5], [6], [7]. While a great deal was learned through a variety of applications to simulators, testbeds and flight experiments, no project adopted the technology in operations and the expected benefits have not yet come to fruition. This led us to ask what are the costs of using MBD for the operational scenarios we encountered, what are the benefits, and how do we approach the question of whether the benefits outweigh the costs? How are missions today approaching fault diagnosis and recovery during operations? If we characterize the cost and benefits of using MBD, how would it compare with traditional ways of making a system more robust? How did expectations for MBD compare to benefits seen in the field and why? The literature does provide existing cost models for related endeavors such as integrated vehicle health management [8], [9], [10]. It also provides excellent narratives of why projects chose not to use MBD after considering it [11]. However, we believe that this paper is the first to unpack and discuss the cost, benefit and risk factors that impact the net value of model-based diagnosis and recovery. We use experience with systems such as Livingstone as an example, so our focus is on-board model-based diagnosis and recovery, but we believe many of the insights and remaining questions on the costs and benefits are applicable to other diagnosis applications. While the analysis is not yet mature enough to provide a quantitative model of when on-board model-based diagnosis would be an effective choice, it lays out the cost/benefit proposition and identifies several disconnects that we believe prevent adoption as an operational tool. While we do not suggest metrics for every cost, benefit and risk factor we identify, we do discuss where each factor arises in development or operations and how model-based diagnosis and recovery tends to leverage or exacerbate each. As such we believe the analysis is of use to those developing MBD or related techniques and those who may employ them. It also serves as one example of how honest expectations based on technical capability can come to differ from the net impact on customer problems. In this paper we present a cost/benefit analysis for MBD, using expectations and experiences with Livingstone as an example. We provide an overview of common techniques for making spacecraft robust, citing fault protection schemes from recent missions [12], [13]. We lay out the cost, benefit and risk advantages associated with on-board MBD, and use the examples to probe each expected advantage in turn. We conclude our analysis with a summary of our method for analyzing the costs and benefits in a particular domain, and encourage others to come forward with analyses of costs and benefits for fielded systems. Finally, we discuss related work both in terms of similar analyses and fielded systems. C1 [Kurien, James] NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. [R-Moreno, Maria Dolores] Univ Alcala de Henares, European Space Agcy, ESTEC, Madrid 28805, Spain. [R-Moreno, Maria Dolores] Univ Alcala De Henares, Dept Automat, Madrid 28805, Spain. RP Kurien, J (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM James.A.Kurien@nasa.gov; mdolores@aut.uah.es NR 34 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4085 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202104 ER PT S AU Bell, DG Brat, GP AF Bell, David G. Brat, Guillaume P. GP IEEE TI Automated software verification & validation: Am emerging approach for ground operations SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Software is an increasingly critical component in aerospace systems, and automated software testing technologies that use formal methods are emerging as a new type of ground data system for verifying and validating software changes. With each change made to software for use in operational settings, there is the opportunity for new bugs to be introduced that can cause potentially catastrophic results. This research has evolved two formal method approaches for automated software verification and validation model checking and static analysis, with extensions of the approaches for multiple languages including Java, C and C++. The research is removing the barriers to routine use of formal methods to gain high assurance for human-rated space missions. These methods have been used on control software for a variety of mission critical systems including guidance, navigation and control (GN&C) subsystems, and for various projects such as the NASA Crew Exploration Vehicle (CEV).(1 2). C1 [Bell, David G.; Brat, Guillaume P.] NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. RP Bell, DG (reprint author), NASA, Ames Res Ctr, USRA RIACS, MS 269-1,MS 269-2, Moffett Field, CA 94035 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4099 EP 4106 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202105 ER PT S AU Maluf, DA Tran, PB Tran, D AF Maluf, David A. Tran, Peter B. Tran, David GP IEEE TI Effective data representation and compression in ground data systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Storing vast amounts of multidimensional telemetry data presents a challenge. Telemetry data being relayed from sensors to the ground station comes in the form of text, images, audio, and various other formats. Compressing this data would optimize bandwidth usage during transmission and reduce storage resources needed at the ground level. However, the multitude of heterogeneous data types present in telemetry data and the need for data precision makes compression quite difficult. The application of a single compression technique for all data types usually yields ineffective results. We will present a telemetry data compression algorithm that utilizes Discrete Fourier Transforms (DFTs) along with different compression algorithms for different data types, including Lempel-Ziv-Welch (LZW) and Flate (which combines LZW with adaptive Huffman coding) for textual and numerical data and JPEG coding for images. Although these algorithms do not yield the greatest compression ratios, the Portable Document Format (PDF) standard supports decoding of 0 of them, which allows us to write our encoded data streams directly to a PDF file. This approach alleviates the need for traditional database storage systems. It also standardizes and simplifies the data retrieval, decoding, and viewing process. This work results in packets-oriented telemetry data encapsulated with multiple compression stream algorithms, which can be decoded, rendered and viewed by any standard PDF viewer. This paper presents the aforementioned algorithms and its development status as applicable proof-of-concept prototypes.(1 2). C1 [Maluf, David A.; Tran, Peter B.] NASA, Ames Res Ctr, Intelligent Syst Div, Mail Stop 269-4, Moffett Field, CA 94035 USA. [Tran, David] Stanford Univ, Stanford, CA 94305 USA. RP Maluf, DA (reprint author), NASA, Ames Res Ctr, Intelligent Syst Div, Mail Stop 269-4, Moffett Field, CA 94035 USA. EM david.a.maluf@nasa.gov; peter.b.tran@nasa.gov; davetran@stanford.edu NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4107 EP + PG 2 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202106 ER PT S AU Saucillo, RJ Reeves, DM Chrone, JD Stromgren, C Reeves, JD North, DD AF Saucillo, Rudolph J. Reeves, David M. Chrone, Jonathan D. Stromgren, Chel Reeves, John D. North, David D. GP IEEE TI Dual mission scenarios for the human lunar campaign - Performance, cost, and risk benefits SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB NASA's future human lunar campaign faces significant performance, cost, and risk challenges. These include: Providing access to large portions of the lunar surface for expanded science and exploration opportunities within the performance constraints of the integrated transportation system Minimizing the annual cost of the lunar campaign Minimizing operational risk, including probability of loss of mission (PLOM) and probability of loss of crew (PLOC) Innovative lunar operations scenarios that address these challenges are potentially feasible based on the concept of dual, sequential missions utilizing a common crew and a single Ares I/Crew Exploration Vehicle (CEV). Dual mission scenarios possible within the scope of baseline technology planning include outpost-based sortie missions, dual sortie missions, and enhanced outpost deployment. Additional mission scenarios are potentially possible with the development of advanced capabilities. These include expanded lunar abort modes and lander reusability options. Top-level benefits of these dual mission scenarios may be estimated by comparison with the Constellation Program reference two-mission-per-year lunar campaign. The primary performance benefit is substantially improved surface access and an increase in payload mass to the lunar surface for Mission B of the two-mission sequence. The cost benefit is the accomplishment of Mission B with a "single launch solution" because no Ares I launch is required. Compared with other single launch solutions that have been proposed, this option provides an additional cost benefit because it does not require the human rating of the Ares V. The PLOM for dual mission scenarios is significantly lower because Mission B does not require the successful launch of two launch vehicles and an orbital rendezvous in time for the translunar injection (TLI) window. Cumulative risk to the crew is lower because crew exposure to Earth launch risks and Earth entry risks is reduced versus comparable Constellation Program reference two-mission-per-year scenarios. C1 [Saucillo, Rudolph J.; Reeves, David M.; North, David D.] NASA, Langley Res Ctr, Space Miss Anal Branch, 1 N Dryden St,Mail Stop 462, Hampton, VA 23681 USA. [Chrone, Jonathan D.] Anal Mech Assoc Inc, Hampton, VA USA. [Stromgren, Chel] SAIC Inc, Mclean, VA USA. RP Saucillo, RJ (reprint author), NASA, Langley Res Ctr, Space Miss Anal Branch, 1 N Dryden St,Mail Stop 462, Hampton, VA 23681 USA. EM Rudolph.J.Saucillo@nasa.gov; David.M.Reeves@nasa.gov; Jonathan.D.Chrone@nasa.gov; Chel.Stromgren@saic.corn; John.D.Reeves@nasa.gov; David.D.North@nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4175 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202114 ER PT S AU Badaruddin, KS AF Badaruddin, Kareem S. GP IEEE TI System testbed use on a mature deep space mission: Cassini SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Cassini-Huygens Program is a joint effort between the European Space Agency (ESA), which delivered the Huygens probe, and the National Aeronautics and Space Administration (NASA), which delivered the Cassini spacecraft. The Jet Propulsion Laboratory (JPL) manages the Cassini spacecraft for NASA. Cassini's primary mission is to survey the complex Saturnian system and release the ESA-Huygens probe at Titan. The Cassini Integrated Test Lab (ITL) at JPL is a high-fidelity hardware-in-the-loop testbed. It uses Attitude and Articulation Control Subsystem (AACS) and Command and Data Subsystem (CDS) flight hardware (H/W), as well as high-fidelity simulations of the other spacecraft subsystems and signals. System Testbeds like the Cassini ITL are often considered to be primarily used in the Final Design and Fabrication Phase and the System Assembly, Integration & Test and Launch Phase of a Mission, but the Cassini ITL has proven to be an essential component of an extremely successful Operations and Sustainment Phase. This paper discusses the role of the Cassini ITL since Cassini's launch, through cruise, orbit insertion at Saturn, probe release at Titan and throughout its tour as Cassini enters the final year of its primary mission. (1 2). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Badaruddin, KS (reprint author), CALTECH, Jet Prop Lab, M-S 230-104,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4190 EP 4198 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202115 ER PT S AU Bennett, M Borgen, R Havelund, K Ingham, M Wagner, D AF Bennett, Matthew Borgen, Richard Havelund, Klaus Ingham, Michel Wagner, David GP IEEE TI Development of a prototype Domain-Specific Language for monitor and control systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper describes the Domain-Specific Language (DSL) prototype developed for the NASA Constellation Launch Control System (LCS) project. A key element of the LCS architecture, the DSL prototype is a specialized monitor and control language composed of constructs for specifying and programming test, checkout, and launch processing applications for flight and ground systems. The principal objectives of the prototyping activity were to perform a proof-of-concept of an approach to ultimately lower the lifecycle costs of application software for the LCS, and to explore mitigations for a number of development risks perceived by the project. The language has been implemented as a library that extends the Python scripting language, and validated in a successful demonstration of capability required for Constellation. (12). C1 [Bennett, Matthew; Borgen, Richard; Havelund, Klaus; Ingham, Michel; Wagner, David] CALTECH, Jet Prop Lab, Flight Software & Data Syst Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Bennett, M (reprint author), CALTECH, Jet Prop Lab, Flight Software & Data Syst Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM matthew.b.bennett@jpl.nasa.gov; richard.l.borgen@jpl.nasa.gov; klaus.havelund@jpl.nasa.gov; michel.d.ingham@jpl.nasa.gov; david.a.wagner@jpl.nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4206 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202117 ER PT S AU Scott, DW AF Scott, David W. GP IEEE TI "Built-In" action/issues tracking and post-ops analysis tool for real-time console operations SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB At Marshall Space Flight Center's (MSFC) Payload Operations Integration Center (POIC) for the International Space Station (ISS), the Payload Communications Manager (PAYCOM) team, whose members speak directly with the ISS onboard crew with respect to NASA payload operations, has found a creative way to reformat a mandatory Daily Report to organize action items, standing reminders, significant events, and other comments. While the report keeps others apprised of PAYCOM's current activities and issues, very brief summaries of the items are put into a "Roll Off Matrix", including start and stop dates, resolution, and possible applicability to future ops. The matrix provides accountability for all action items, gives direct insight into issues regarding payloads, control center operations, and methods, yields indirect information on PAYCOM priorities and processes, and provides a roadmap for locating extensive details if needed. This paper describes how the Daily Report and Roll Off Matrix are organized, used, and inter-related to each other and the PAYCOM operations log. While the application is for a manned vehicle, the concepts could apply in a wide spectrum of operational settings. (12). C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Scott, DW (reprint author), NASA, George C Marshall Space Flight Ctr, EO20, Huntsville, AL 35812 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4266 EP 4275 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202122 ER PT S AU Maluf, DA Tran, PB AF Maluf, David A. Tran, Peter B. GP IEEE TI Managing unstructured data with structured legacy systems SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In this paper we describe an approach and system for managing and joining enterprise semi-structured data in a high-throughput, nimble, and scalable systems with traditional relational database management systems (RDBMS). This paper presents the second release of NASA's NETMARK system. NETMARK is an Enterprise Information Integration (EH) framework based on a modem "schema-less" concept approach. NETMARK "schema-less" information integration reinvents the way of managing semi-structured documents within traditional RDBMS. We describe in particular detail the unique underlying data storage approach and efficient query processing mechanisms given the new proposed storage system upgrade. We present an extensive evaluation of the virtual union between NETMARK with the persistent schemas similar to commercial off-the-self products, such as Systems Applications and Products (SAP), currently utilized for NASA's Financial System, through well validated applications. At the heart of the approach is the philosophy of a well-defined and focused approach on most common data management requirements in the enterprise, and not burdening users and application developers with unnecessary complexity and formal data integration processes. This paper presents the details of achieving the integration between two incompatible systems. (1 2). C1 [Maluf, David A.; Tran, Peter B.] NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. RP Maluf, DA (reprint author), NASA, Ames Res Ctr, Intelligent Syst Div, Mail Stop 269-4, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4276 EP 4280 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202123 ER PT S AU Hardash, JAC McGurk, S AF Hardash, Jill A-C McGurk, Sheryl GP IEEE TI Credible space cost estimating policy for NASA: Making sensible requirements work SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB With the introduction of the 2008 NASA Cost Estimating Handbook (CEH) comes a new responsibility. The 2008 CEH provides credible cost estimating policy for NASA which has been streamlined to make references easy to find and new initiatives simple to understand and communicate to others. The challenge is one of implementation. The cost estimating capability at NASA has reached a point of maturity. Program and Project Managers have come to expect the involvement of the cost estimators on their team. Major programs including Constellation have written Affordability Plans and conducted Cost Confidence Level Assessments for their programs. The NASA Administrator understands and expects to see probabilistic cost estimates. Cost has a much wider audience at NASA than ever before. The initiatives and new policies have been created by the experts within and adopted by the agency. Now the challenge is for all to consistently interpret and implement the policies resulting in cost effective programs for NASA. The NASA CEH contains the details introduced in NASA Program Requirement (NPR) 7120.5d. This paper focuses on the streamlined requirements of the 2008 NASA CEH and the approach the cost estimators at NASA are using to implement these requirements to a wider audience. Once this was a reference for the cost community, now it has become a sensible requirement for successful programs and the cost estimators are the responsible ambassadors for this Policy. C1 [Hardash, Jill A-C] Booz Allen Hamilton, 5220 Pacific Concourse Dr,Ste 390, Los Angeles, CA 90045 USA. [McGurk, Sheryl] NASA, Program Anal & Evaluat, Washington, DC 20546 USA. RP Hardash, JAC (reprint author), Booz Allen Hamilton, 5220 Pacific Concourse Dr,Ste 390, Los Angeles, CA 90045 USA. EM Hardash_Jill@BAH.com; smcgurk@hq.nasa.gov NR 4 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4308 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202126 ER PT S AU Bryson, JG Brill, SR McGurk, S AF Bryson, Jonathan G. Brill, Steven R. McGurk, Sheryl GP IEEE TI NASA's cost analysis steering group as a community of practice SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The National Aeronautics and Space Administration (NASA) and other Federal agencies face a wave of retirements in the near future which could lead to a significant loss of experience and knowledge. As a response, the organizations need to utilize multiple strategies to capture, retain, and transfer knowledge and to maintain skill competency. This paper describes the use of the concept of a "community of practice" (CoP) and the initial steps to develop an Agency-wide discipline group for cost estimation and analysis into a more highly functioning community for the purpose of successful knowledge management. CoP resources from academia and other Federal sources are identified. A new model of a Knowledge Curriculum is also introduced.(1,2) C1 [Bryson, Jonathan G.] NASA, Goddard Space Flight Ctr, Earth Sci Projects Div 420, Greenbelt, MD 20771 USA. [Brill, Steven R.] NASA, Comp Sci Corp, Engn & Program Management Div, Washington, DC USA. [McGurk, Sheryl] NASA, Off Program Anal & Evaluat, Cost Anal Div, Washington, DC USA. RP Bryson, JG (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Projects Div 420, Greenbelt, MD 20771 USA. EM Jonathan.G.Bryson@nasa.gov; sbrill1@csc.com; sheryl.mcgurk-1.@nasa.gov NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4317 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202127 ER PT S AU Aster, R AF Aster, Robert GP IEEE TI Lessons learned from developing new engineering managers at JPL SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB Engineers who become managers must acquire essential knowledge about management to be successful. Major aerospace projects are complex organizations with three or four levels of management, and often have over a hundred cost account managers. Management skills are critical to the planning and implementation of these projects, especially in today's cost-conscious world. Aerospace organizations must address the gaps between excellent engineering educations and excellent knowledge about engineering management if they hope to succeed with major aerospace projects. Essential engineering management knowledge includes how to: plan work, estimate cost, prepare schedules, manage performance under normal circumstances, manage performance under adverse circumstances, and handle people. While some engineering students learn about cost estimation in their university education, many do not. Few engineering students get significant training on the other management skills mentioned above. However, the best and brightest engineers often become cost account managers within several years after they graduate, and many of these move on to higher levels of management within several more years. Their management skills, or lack thereof, lead directly to the success or failure of complex aerospace projects. There are at least four approaches for developing engineering managers: (1) let them watch other managers perform on real jobs; (2) active mentoring; (3) self-directed study of books and journal articles on management; (4) formal training sponsored by the employer. Formal training is the foundation for sound development of engineering managers. All of the other approaches can be helpful, but are seriously undermined if formal training is absent or otherwise inadequate. Bad habits and inconsistent practices can be learned, until the organization gets itself into serious trouble. This paper(1 2) describes successful practices at JPL in developing engineering managers through formal training. The author has been engaged in project and proposal work for over thirty years at JPL, and in formal training over the last ten years. Over the last decade he has addressed the needs of approximately 1,500 students. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Aster, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4324 EP 4331 PG 8 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202128 ER PT S AU Jones, MA Chase, JP AF Jones, Melissa A. Chase, James P. GP IEEE TI Conceptual design methods and the application of a tradespace modeling tool for deep space missions SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SYSTEMS AB Concept studies for deep space missions are typically time-consuming and costly, given the variety of missions and uniqueness of each design. Yet, in an increasingly cost-constrained environment, it is critical to identify the most scientifically valuable and cost-effective designs early in the design process. Modeling is an integral part in helping to identify the most desirable design option. While some spacecraft design models currently exist for Earth-orbiting spacecraft, there has been less success with deep space missions. Instead, these missions require a modified design and modeling approach to enable the same construction of a comprehensive, yet credible, mission tradespace. This paper presents an approach for efficiently constructing such a mission tradespace. In addition to a proposed design and modeling approach, three case study missions are presented including a solar orbiter, a Europa orbiter, and a near-Earth asteroid (NEA) sample return mission. C1 [Jones, Melissa A.; Chase, James P.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jones, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4340 EP 4354 PG 15 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202130 ER PT S AU Lee, M Weidner, RJ AF Lee, Meemong Weidner, Richard J. GP IEEE TI Juno mission simulation SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The Juno spacecraft is planned to launch in August of 2012 and would arrive at Jupiter four years later. The spacecraft would spend more than one year orbiting the planet and investigating the existence of an ice-rock core; determining the amount of global water and ammonia present in the atmosphere, studying convection and deep-wind profiles in the atmosphere; investigating the origin of the Jovian magnetic field, and exploring the polar magnetosphere. Juno mission management is responsible for mission and navigation design, mission operation planning, and ground-data-system development. In order to ensure successful mission management from initial check-out to final de-orbit, it is critical to share a common vision of the entire mission operation phases with the rest of the project teams. Two major challenges are 1) how to develop a shared vision that can be appreciated by all of the project teams of diverse disciplines and expertise, and 2) how to continuously evolve a shared vision as the project lifecycle progresses from formulation phase to operation phase. The Juno mission simulation team addresses these challenges by developing agile and progressive mission models, operation simulations, and real-time visualization products. This paper presents mission simulation visualization network (MSVN) technology that has enabled a comprehensive mission simulation suite (MSVN-Juno) for the Juno project. C1 [Lee, Meemong; Weidner, Richard J.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4355 EP 4363 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202131 ER PT S AU Terrile, RJ Lee, S Tinetti, G Fink, W von Allmen, P Huntsberger, TL AF Terrile, Richard J. Lee, Seungwon Tinetti, Giovanna Fink, Wolfgang von Allmen, Paul Huntsberger, Terrance L. GP IEEE TI Evolutionary Computational Methods for the design of spectral instruments SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID EARTHSHINE AB We have developed a technique based on Evolutionary Computational Methods (ECM) that allows for the automated optimization of complex computationally modeled systems. We have demonstrated that complex engineering and science models can be automatically inverted by incorporating them into evolutionary frameworks and that these inversions have advantages over conventional searches by not requiring expert starting guesses (designs) and by running on large cluster computers with less overall computational time than conventional approaches. We have applied these techniques to the automated retrieval of atmospheric and surface spectral signatures from Earthshine observational data. We have demonstrated that in addition to automated spectral retrieval, ECM can also be used to evaluate the discriminability of scientific results as a function of requirements placed on the spectral model. An important application of this technique is for the optimization of design parameters for spectral instruments. C1 [Terrile, Richard J.; Lee, Seungwon; Fink, Wolfgang; von Allmen, Paul; Huntsberger, Terrance L.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Tinetti, Giovanna] UCL, European Space Agcy, London WC1E 6BT, England. RP Tinetti, G (reprint author), UCL, European Space Agcy, London WC1E 6BT, England. EM rich.terrile@jpl.nasa.gov; g.tinetti@ucl.ac.uk NR 26 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4364 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202132 ER PT S AU Lee, CH Cheung, KM AF Lee, Charles H. Cheung, Kar-Ming GP IEEE TI Communication-centric spacecraft design optimization tool and its application to the lunar relay satellite design SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The process of spacecraft design is highly complicated and often requires in-depth trade studies that involve a large number of variables in vast search spaces. Leading factors such as payload, technological capabilities, and trajectory, to name a few, are traded against costs. It is highly desirable to have a design tool at the early conceptual phases that could lead to an optimal design of the system and prevent unforeseen setback, cumbersome mission operations, or budget overrun. In this paper, we propose a communication-centric spacecraft design optimization tool, to be used at the beginning of the spacecraft design phases, to assess the design performance based on communication metrics. The considered tool takes into account the dynamic geometry of the spacecraft, either an orbiter or a landing asset, along with the planetary ephemeris and spacecraft telecom systems to calculate the telecom metrics of interest to optimize the design. Key spacecraft design parameters will be quantified from the communication perspective by the proposed tool, including optimal aperture size, the need of a gimbal mechanism for the antenna, and the required transmitting power, etc. In addition, the tool can optimize the overall layout of the spacecraft antennas, the solar panels, and other onboard instruments. Simulations from the proposed tool can suggest where the appropriate devices can be placed to ensure constant and unobstructed view. It can point out possible risks of the maneuvers in order for the spacecraft to maintain the desired position by identifying how frequently and how elaborately the spacecraft must be oriented.(1,2) Preliminary work has been implemented for a future lunar relay satellite to be launched no later than 2020 to provide relay communication service to a human base stationed in the Southern Polar region. Discussion on how the tool can align the design parameters with the lunar infrastructure communication needs and how the antenna should be oriented, including pointing strategy will also be presented. C1 [Lee, Charles H.; Cheung, Kar-Ming] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4373 EP 4379 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202133 ER PT S AU Owens, BD Herring, MS Dulac, N Leveson, NG Ingham, MD Weiss, KA AF Owens, Brandon D. Herring, Margaret Stringfellow Dulac, Nicolas Leveson, Nancy G. Ingham, Michel D. Weiss, Kathryn Anne GP IEEE TI Application of a safety-driven design methodology to an outer planet exploration mission SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE ID SYSTEMS AB Traditional requirements specification and hazard analysis techniques have not kept pace with the increasing complexity and constraints of modem space systems development. These techniques are incomplete and often consider safety late in the development cycle when the most significant design decisions have already been made. The lack of an integrated approach to perform safety-driven system development from the beginning of the system lifecycle hinders the ability to create safe space systems on time and within budget. To address this need, the authors have created an integrated methodology for safety-driven system development that combines four state-of-the-art techniques: 1) Intent Specification, a framework for organizing system development and operational information in a hierarchical structure; 2) the STAMP model of accident causation, a system-theoretic framework upon which to base more powerful safety engineering techniques; 3) STAMP-based Hazard Analysis (STPA); and 4) State Analysis, a model-based systems engineering approach. The iterative approach specified in the methodology employs State Analysis in the modeling of system behavior. STPA is used to identify system hazards and the constraints that must be enforced to mitigate these hazards. Finally, Intent Specification is used to document traceability of behavioral requirements and subject them to formal analysis using the SpecTRM-RL software package. In this paper, 1,2 the application of this methodology is demonstrated through the specification of a spacecraft high gain antenna pointing mechanism for a hypothetical outer planet exploration mission. C1 [Owens, Brandon D.; Herring, Margaret Stringfellow; Dulac, Nicolas; Leveson, Nancy G.] MIT, Complex Syst Res Lab, 77 Massachusetts Ave,Bldg 33-407C, Cambridge, MA 02139 USA. [Ingham, Michel D.; Weiss, Kathryn Anne] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Owens, BD (reprint author), MIT, Complex Syst Res Lab, 77 Massachusetts Ave,Bldg 33-407C, Cambridge, MA 02139 USA. EM owensbd@mit.edu; sapphire@mit.edu; ndulac@mit.edu; leveson@mit.edu; Michel.D.Ingham@jpl.nasa.gov; Kathryn.A.Weiss@jpl.nasa.gov FU Massachusetts Institute of Technology [1297013]; Jet Propulsion Laboratory; California Institute of Technology FX This research was performed at the Massachusetts In stitute of Technology (supported through JPL University Subcontract 1297013), and at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 14 TC 0 Z9 0 U1 1 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4380 EP + PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202134 ER PT S AU Jansma, PA AF Jansma, P. A. (Trisha) GP IEEE TI A field guide to the NASA Procedural Requirements for systems engineering SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In March 2007, NASA issued the new NASA Procedural Requirements (NPR) for systems engineering NPR 7123.1A NASA Systems Engineering Processes and Requirements - as part of the NASA systems engineering framework. This NPR "establishes a core set of common Agency-level technical processes and requirements needed to define, develop, realize, and integrate the quality of the system products created and acquired by or for NASA." The processes described in the NPR are intended to "clearly delineate a successful model to complete comprehensive technical work, reduce program and technical risk, and improve mission success." The rationale for the Systems Engineering (SE) NPR is the fact that "systems engineering at NASA requires the application of a systematic, disciplined engineering approach that is quantifiable, recursive, iterative, and repeatable for the development, operation, maintenance, and disposal of systems integrated into a whole throughout the life-cycle of a project or program. The emphasis of systems engineering is on safely achieving stakeholder functional, physical, and operational performance requirements in the intended use environments over the system's planned life within cost and schedule constraints."[6] This paper(1,2) provides an overview of NPR 7123.1A, including institutional and programmatic requirements, requirements for common technical processes, NASA oversight activities on contracted projects, systems engineering technical reviews, and the purpose and function of a Systems Engineering Management Plan (SEMP). It also includes an overview of the practices for common technical processes - system design processes, technical management processes, and product realization processes as well as a discussion of the entrance and success criteria for technical reviews. It concludes with how the NPR is being implemented across the Agency, how NASA systems engineers are being trained in its use, and the impact of the NPR to date. C1 CALTECH, Jet Prop Lab, Syst Engn Advancement Project, Pasadena, CA 91109 USA. RP Jansma, PA (reprint author), CALTECH, Jet Prop Lab, Syst Engn Advancement Project, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Patti.A.Jansma@jpl.nasa.gov NR 15 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4404 EP 4419 PG 16 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202135 ER PT S AU Derro, ME Jansma, PA AF Derro, Mary Ellen Jansma, P. A. (Trisha) GP IEEE TI Coaching valuable systems engineering behaviors SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB The JPL Systems Engineering Advancement (SEA) Project was launched in FY2004 to advance the practice of systems engineering at JPL, and to address the three key aspects of change: people, process and technology. A significant portion of the People component of the SEA Project is devoted to systems engineering training. The SEA trains systems engineers according to a three-pronged systems engineering competency model. This competency model includes technical domain knowledge, understanding of systems engineering standards, processes and practices, and highly valued behavioral attributes. The SEA Project utilized a rigorous process to identify a list of highly valued personal behaviors of systems engineers. The process yielded common themes and clusters of competencies with associated behaviors. The behavioral attributes fall into four broad themes: leadership, communication, problem solving and systems thinking, and attitudes and attributes. This paper(1,2) summarizes the method, findings, and conclusions of the study of behavioral competencies of highly regarded systems engineers at JPL. It details the competencies and associated behaviors for each of the themes in depth, and discusses the Lab's experience to date in coaching and inculcating these behaviors into systems engineers on the job. C1 [Derro, Mary Ellen; Jansma, P. A. (Trisha)] CALTECH, Jet Prop Lab, Human Resources Directorate, Syst Engn Advancement Project,Profess Dev Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Derro, ME (reprint author), CALTECH, Jet Prop Lab, Human Resources Directorate, Syst Engn Advancement Project,Profess Dev Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Maryellen.Derro@jpl.nasa.gov; Patti.A.Jansma@jpl.nasa.gov NR 26 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4420 EP + PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202136 ER PT S AU Meshkat, L Jenkins, S Mandutianu, S Heron, V AF Meshkat, Leila Jenkins, Steve Mandutianu, Sanda Heron, Vance GP IEEE TI Automated generation of risk and failure models during early phase design SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB A functional model of a space mission represents the various functions that need to succeed in order for the mission to be successful. The various outcomes of each of these functions and their combinations determine the different possible outcomes for the mission. Recent research and development by Jenkins and Heron has led to the development of a common ontology that is used to completely specify the important attributes of a space mission; including the risks and failures. Using this ontology, we have organized the information obtained at the preliminary design phase of a sample space mission and linked the various attributes together within the context of the Systems Engineering tool, CORE3. In this paper, we elaborate on the process of developing automated risk and failure models by examining the possible combinations and order of events that can occur with respect to the existing elements of the ontology, and by leveraging on the existing body of work in the area of systems modeling and ontology development, as well as dynamic fault trees. We generate the dynamic fault tree corresponding with the functional model developed in CORE, and then develop a generalized algorithm for the conversion of functional models into dynamic fault trees. It is important to note that once a dynamic fault tree has been generated, it is possible to conduct quantitative risk assessment studies, sensitivity analysis, and minimal cutset analysis by exercising the dynamic fault tree. Hence the organization of the mission information in CORE not only allows for the specification of the mission attributes, but also enables further analysis of the system. C1 [Meshkat, Leila; Jenkins, Steve; Mandutianu, Sanda; Heron, Vance] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meshkat, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4447 EP 4458 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202138 ER PT S AU White, AL AF White, Allan L. GP IEEE TI Sensitivity study for long term reliability SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB This paper illustrates using Markov models to establish system and maintenance requirements for small electronic controllers where the goal is a high probability of continuous service for a long period of time. The system and maintenance items considered are quality of components, various degrees of simple redundancy, redundancy with reconfiguration, diagnostic levels, periodic maintenance, and preventive maintenance. Markov models permit a quantitative investigation with comparison and contrast. An element of special interest is the use of conditional probability to study the combination of imperfect diagnostic and periodic maintenance. C1 NASA Langley, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA Langley, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4466 EP 4474 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202140 ER PT S AU Peterson, C Cutts, J Balint, T Hall, JB AF Peterson, Craig Cutts, James Balint, Tibor Hall, James B. GP IEEE TI Rapid cost assessment of space mission concepts through application of complexity-based cost indices SO 2008 IEEE AEROSPACE CONFERENCE, VOLS 1-9 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT 2008 IEEE Aerospace Conference CY MAR 01-08, 2008 CL Big Sky, MT SP IEEE AB In 2005, the Solar System Exploration Strategic Roadmap Committee (chartered by NASA to develop the roadmap for Solar System Exploration Missions for the coming decades) found itself posed with the difficult problem of sorting through several mission concepts and determining their relative costs. While detailed mission studies are the normal approach. to costing, neither the budget nor schedule allotted to the committee could support such studies. Members of the Jet Propulsion Laboratory (JPL) supporting the committee were given the challenge of developing a semi-quantitative approach that could provide the relative costs of these missions, without requiring an in depth study of the missions. In response to this challenge, a rapid cost assessment methodology based on a set of mission cost/complexity indexes was developed. This methodology also underwent two separate validations, one comparing its results when applied to historical missions, and another comparing its estimates against those of veteran space mission managers. Remarkably good agreement was achieved, suggesting that this approach provides an effective early indication of space mission costs. C1 [Peterson, Craig; Cutts, James; Balint, Tibor; Hall, James B.] CALTECH, Jet Prop Lab, Miss Syst Concepts Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Peterson, Craig; Cutts, James; Balint, Tibor; Hall, James B.] Jet Prop Lab, Pasadena, CA 91109 USA. RP Peterson, C (reprint author), CALTECH, Jet Prop Lab, Miss Syst Concepts Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Craig.Peterson@jpl.nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 978-1-4244-1487-1 J9 AEROSP CONF PROC PY 2008 BP 4519 EP + PG 3 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BIC00 UT WOS:000258321202146 ER PT B AU Llombart, N Bradford, CM Neto, A Chattopadhyay, G AF Llombart, N. Bradford, C. M. Neto, A. Chattopadhyay, G. GP IEEE TI Impedance Matching of a Micromesh Bolometer Placed in a Silicon Parallel Plate Waveguide Spectrometer SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Llombart, N.; Bradford, C. M.; Chattopadhyay, G.] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. [Neto, A.] TNO Def Secur & Safety, The Hague, Netherlands. RP Llombart, N (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 248 EP + PG 2 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600063 ER PT B AU Cable, VP AF Cable, Vaughn P. GP IEEE TI Patch Antennas for VHF vs Ka-band The Very Large & the Very Small SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cable, VP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 603 EP 606 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600152 ER PT B AU Lee, RQ Chun, K AF Lee, Richard Q. Chun, Kue GP IEEE TI Compact Miniaturized Antenna for 210 MHz RFID SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE ID SLOT-ANTENNA C1 [Lee, Richard Q.; Chun, Kue] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lee, RQ (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 675 EP 678 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600170 ER PT B AU Llombart, N Skalare, A Siegel, PH AF Llombart, N. Skalare, A. Siegel, P. H. GP IEEE TI High-Efficiency Array for Submillimeter-Wave Imaging Applications SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Llombart, N.; Skalare, A.; Siegel, P. H.] CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Llombart, N (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 787 EP 790 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600198 ER PT B AU Rajagopalan, H Rahmat-Samii, Y Imbriale, WA AF Rajagopalan, Harish Rahmat-Samii, Yahya Imbriale, William A. GP IEEE TI Integration of RF MEMS Switches with the Reconfigurable Reflectarray Element: A Novel Patch-Slot Implementation SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Rajagopalan, Harish; Rahmat-Samii, Yahya] Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. [Imbriale, William A.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rajagopalan, H (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. EM harish@ee.ucla.edu; rahmat@ee.ucla.edu; imbriale@jpl.nasa.gov FU Jet Propulsion Laboratory California Institute of Technology; National Aeronautics and Space Administration FX This work was supported in part by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 1024 EP + PG 3 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600258 ER PT B AU Scardelletti, MC Ponchak, GE Jordan, JL Merritt, SJ AF Scardelletti, Maximilian C. Ponchak, George E. Jordan, Jennifer L. Merritt, Shane J. GP IEEE TI Reduced Size Folded Slot Antennas with Capacitive Loading SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Scardelletti, Maximilian C.; Ponchak, George E.; Jordan, Jennifer L.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. [Merritt, Shane J.] Univ Iowa, Iowa City, IA 52240 USA. RP Scardelletti, MC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Maximilian.C.Scardelletti@nasa.gov FU Wireless Communications group of the Integrated Vehicle Health Management (IVHM) project at NASA FX The authors would like to thank Elizabeth McQuaid for her CAD and fabrication efforts. This work was supported by the Wireless Communications group of the Integrated Vehicle Health Management (IVHM) project at NASA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 1116 EP 1119 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440600281 ER PT B AU Jamnejad, V Hoorfar, A AF Jamnejad, Vahraz Hoorfar, Ahmad GP IEEE TI Optimization of Antenna Beam Transmission Efficiency SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Jamnejad, Vahraz] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Hoorfar, Ahmad] Villanova Univ, ECE Dept, Villanova, PA 19085 USA. RP Jamnejad, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Vahraz.jamnejad@jpl.nasa.gov FU Jet Propulsion Laboratory; California Institute of Technology; National Aeronautics and Space Administration FX This work was supported in part by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 1784 EP + PG 3 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440601059 ER PT B AU Rengarajan, SR Zawaki, MS Hodges, RE AF Rengarajan, Sembiam R. Zawaki, Mark S. Hodges, Richard E. GP IEEE TI Slot Array Antennas for the Juno Radiometer Application SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Rengarajan, Sembiam R.] Calif State Univ Northridge, Dept Elect & Comp Engn, Northridge, CA 91330 USA. [Rengarajan, Sembiam R.; Zawaki, Mark S.; Hodges, Richard E.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rengarajan, SR (reprint author), Calif State Univ Northridge, Dept Elect & Comp Engn, Northridge, CA 91330 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 1986 EP + PG 3 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440601110 ER PT B AU Jordan, JL Scardelletti, M Ponchak, GE AF Jordan, Jennifer L. Scardelletti, Maximilian Ponchak, George E. GP IEEE TI A 1 GHz Oscillator-Type Active Antenna SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Jordan, Jennifer L.; Scardelletti, Maximilian; Ponchak, George E.] NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Jordan, JL (reprint author), NASA Glenn Res Ctr, Cleveland, OH 44135 USA. EM Jennifer.L.Jordan@nasa.gov NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 2454 EP 2457 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440601226 ER PT B AU Yu, A Yang, F Elsherbeni, AZ Huang, J AF Yu, Ang Yang, Fan Elsherbeni, Atef Z. Huang, John GP IEEE TI An X-Band Circularly Polarized Reflectarray Using Split Square Ring Elements and the Modified Element Rotation Technique SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Yu, Ang; Yang, Fan; Elsherbeni, Atef Z.] Univ Mississippi, CAESR, Dept Elect Engn, University, MS 38677 USA. [Huang, John] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RP Yu, A (reprint author), Univ Mississippi, CAESR, Dept Elect Engn, University, MS 38677 USA. EM ayu@olemiss.edu; fyang@olemiss.edu; atef@olemiss.edu; john.huang@jpl.nasa.gov NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 3355 EP 3358 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440602068 ER PT B AU Tavassolian, N Ponchak, GE Papapolymerou, J AF Tavassolian, Negar Ponchak, George E. Papapolymerou, John GP IEEE TI Compact Conformal Dipole Antenna on Organic Substrate for 2.4 GHz Applications SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Tavassolian, Negar; Papapolymerou, John] Georgia Inst Technol, Atlanta, GA 30332 USA. [Ponchak, George E.] NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Tavassolian, N (reprint author), Georgia Inst Technol, Atlanta, GA 30332 USA. EM negar@ece.gatech.edu NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 3667 EP 3670 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440602146 ER PT B AU Scardelletti, MC Zorman, CA Oldham, DR AF Scardelletti, Maximilian C. Zorman, Christian. A. Oldham, Daniel R. GP IEEE TI RF MEMS Switches with SiC Microbridges for Improved Reliability SO 2008 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM, VOLS 1-9 LA English DT Proceedings Paper CT IEEE Antennas-and-Propagation-Society International Symposium CY JUL 05-11, 2008 CL San Diego, CA SP IEEE C1 [Scardelletti, Maximilian C.; Oldham, Daniel R.] NASA Glenn Res Ctr, Cleveland, OH 44135 USA. [Zorman, Christian. A.] Case Western Reserve Univ, Cleveland, OH 44106 USA. RP Scardelletti, MC (reprint author), NASA Glenn Res Ctr, Cleveland, OH 44135 USA. EM Maximilian..C.Seardelletti@nasa.gov FU Wireless Communications group at NASA FX The authors would like to thank Elizabeth McQuaid and Nick Varaljay for their CAD and fabrication efforts. This work was supported by the Wireless Communications group of the Integrated Vehicle Health Management (IVHM) project at NASA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2041-4 PY 2008 BP 4030 EP + PG 3 WC Engineering, Electrical & Electronic; Physics, Applied; Telecommunications SC Engineering; Physics; Telecommunications GA BIO99 UT WOS:000261440602237 ER PT S AU Sonnenfeld, G Goebel, K Celaya, JR AF Sonnenfeld, Greg Goebel, Kai Celaya, Jose R. GP IEEE TI An Agile Accelerated Aging, Characterization and Scenario Simulation System for Gate Controlled Power Transistors SO 2008 IEEE AUTOTESTCON, VOLS 1 AND 2 SE IEEE Autotestcon LA English DT Proceedings Paper CT 43rd Annual IEEE AUTOTESTCON Conference CY SEP 08-11, 2008 CL Salt Lake City, UT SP IEEE Aerosp & Elect Syst Soc DE prognostics; aging; characterization; damage progression; semiconductor test systems; degradation; electronics; remaining useful life; IGBT and MOSFET ID SEMICONDUCTOR MODULES AB To advance the field of electronics prognostics, the study of transistor fault modes and their precursors is essential. This paper reports on a platform for the aging, characterization, and scenario simulation of gate controlled power transistors. The platform supports thermal cycling, dielectric over-voltage, acute/chronic thermal stress, current overstress and application specific scenario simulation. In addition, the platform supports in-situ transistor state monitoring, including measurements of the steady-state voltages and currents, measurements of electrical transient response, measurement of thermal transients, and extrapolated semiconductor impedances, all conducted at varying gate and drain voltage levels. The aging and characterization platform consists of an acquisition and aging hardware system, an agile software architecture for experiment control and a collection of industry developed test equipment. C1 [Sonnenfeld, Greg; Goebel, Kai] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Celaya, Jose R.] NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. RP Sonnenfeld, G (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM greg.r.sonnenfeld@nasa.gov; kai.goebel@nasa.gov; jcelaya@mail.arc.nasa.gov NR 19 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1088-7725 BN 978-1-4244-2225-8 J9 IEEE AUTOTESTCON PY 2008 BP 325 EP + PG 2 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIZ84 UT WOS:000264052700063 ER PT S AU Mazumder, MK Sharma, R Biris, AS Horenstein, MN Trigwell, S Abbas, MM AF Mazumder, M. K. Sharma, R. Biris, A. S. Horenstein, M. N. Trigwell, S. Abbas, M. M. GP IEEE TI Electrostatic and Gravitational Transport of Lunar Dust in the Airless Atmosphere of the Moon SO 2008 IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING, VOLS 1-5 SE IEEE Industry Applications Society Annual Meeting LA English DT Proceedings Paper CT IEEE Industry-Applications-Society Annual Meeting CY OCT 05-09, 2008 CL Alberta, CANADA SP Ind Applicat Soc DE lunar dust; mars dust; dust mitigation; electrostatic charging; photoemission AB Since its formation about 4.6 billion years ago, the surface of the moon has become covered with a thick layer of fine dust which has been preserved in a pristine, ultrahigh vacuum condition without any atmosphere-related changes of its physical properties and chemical compositions. The lunar surface has no atmosphere. Yet, Apollo and surveyor missions observed there is an atmospheric glow in the horizon and streamers of dust arising from the surface and scattering solar radiation during the sunrise. Apollo astronauts saw fountains of lunar dust rising hundreds of kilometers above the surface. The Apollo landing sites showed that the moon is virtually an ocean of electrostatically charged dust containing fractured glass-like particles with a high adhesive property. We present here an analysis of electrostatic charging by the photoemission and solar plasma electrons based on the current understanding of surface dust and the environmental conditions of the moon. The photon-particle interactions causing the particles to be positively charged during the day negatively charged during the night by solar wind including the effect of the earth's magnetosphere. The cyclical charging and charge neutralization processes are briefly discussed in view of the observed electrostatic levitation of the dust. As the moon rotates on its axis, the dividing boundary line between the illuminated (sunlit) and the shaded (dark) regions, called the terminator, across which the charge polarity of dust layer and the intensity and the electric field change, also rotates. The reversal of direction of the electric field along the dividing line and the rotational motion cause dust trajectories to cross the terminator. Possible inhalation hazards of the toxic surface reactive dust with sharp edges in the nano- and micrometer size ranges are considered to be high in view of the increased lung deposition efficiency caused by the electrostatic image and space charge forces. A clear understanding of the lunar dust dynamics is needed for developing effective dust hazard mitigation for future robotic and human missions to the moon. C1 [Mazumder, M. K.; Sharma, R.; Biris, A. S.] Univ Arkansas, Dept Appl Sci, Little Rock, AR 72204 USA. [Trigwell, S.] NASA, Kennedy Space Ctr, Appl Sci & Technol, ASRC Aerospace, Kennedy Space Ctr, FL 32899 USA. [Horenstein, M. N.] Boston Univ, Dept Elect & Comp Engn, Boston, MA 02115 USA. NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Mazumder, MK (reprint author), Univ Arkansas, Dept Appl Sci, Little Rock, AR 72204 USA. FU NASA [NRA 02-0SS-01]; JPL [1263202] FX The research was supported by a NASA Grant NRA 02-0SS-01 (ROSS- 2002), JPL Contract No. 1263202 NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0197-2618 BN 978-1-4244-2278-4 J9 IEEE IND APPLIC SOC PY 2008 BP 2236 EP + PG 2 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BIW69 UT WOS:000263417001099 ER PT S AU Huston, A Zhang, Y Zhang, GF Yeary, M Neece, RT AF Huston, Andrew Zhang, Yan Zhang, Guifu Yeary, Mark Neece, Robert T. GP IEEE TI A LABORATORY STUDY FOR DUAL-POLARIZATION SCATTERING CHARACTERISTICS OF METEOROLOGICAL OBJECTS SO 2008 IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1-5 SE IEEE Instrumentation and Measurement Technology Conference LA English DT Proceedings Paper CT 25th IEEE Instrumentation and Measurement Technology Conference CY MAY 12-15, 2008 CL Victoria, CANADA SP IEEE Instrumentat & Measurement Soc DE Dual-polarization; Scattering; Hydrometeors; Scatterometer ID RADAR; SIGNATURES AB Radar sensors with dual-polarization capability allow a better understanding and characterization of weather hazards. Especially, scattering characteristics become important for optimally designing and utilizing phase-array dual-polarization radar systems. In this investigation, an experimental approach was designed with the assistance of a controlled laboratory environment. As such, an advanced network analyzer-based scatterometer system has been developed in harmony with a new room that resembles an anechoic chamber. As discussed in the results section of this paper, the instrumented facility allows for key radar cross-section (RCS) parameters and preliminary validations through detailed scattering measurements. C1 [Huston, Andrew; Zhang, Yan; Zhang, Guifu; Yeary, Mark] Univ Oklahoma, Sch Elect & Comp Engn, Norman, OK 73072 USA. [Neece, Robert T.] Langley Res Ctr, NASA, Hampton, VA USA. RP Zhang, Y (reprint author), Univ Oklahoma, Sch Elect & Comp Engn, Norman, OK 73072 USA. EM rockee@ou.edu FU NASA-Langley Research Center [NNX07AN15A] FX This work is partially supported by the NASA-Langley Research Center (grant # NNX07AN15A). The authors greatly appreciate for the comments and guidance from Dr. Robert Neece, Mr. Steven Harrach and other NASA researchers. The hailstones were collected by OU students Matthew Kumjian and Alexander Schenkman. This work has also received important help from the National Severe Storm Laboratory (NSSL) and the members of the Atmospheric Radar Research Center (ARRC), in the University of Oklahoma. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 978-1-4244-1540-3 J9 IEEE IMTC P PY 2008 BP 507 EP + DI 10.1109/IMTC.2008.4547088 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BIP18 UT WOS:000261512100096 ER PT S AU Schmalzel, JL Figueroa, F Mandayam, SA AF Schmalzel, John L. Figueroa, Fernando Mandayam, Shreekanth A. GP IEEE TI A Road Manp for Integrated Systems Health Management SO 2008 IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1-5 SE IEEE Instrumentation and Measurement Technology Conference LA English DT Proceedings Paper CT 25th IEEE Instrumentation and Measurement Technology Conference CY MAY 12-15, 2008 CL Victoria, CANADA SP IEEE Instrumentat & Measurement Soc DE Anomaly Detection; Health Management; Intelligent Sensors; ISHM; Smart Sensors ID MAINTENANCE AB Integrated systems health management (ISHM) is one of several approaches to building automated diagnostic and prognostic systems. We describe a unique architecture for ISHM along with other key technology elements such as Smart Sensors complying with the IEEE 1451.x family of standards, and user interaction methods. Technology readiness levels (TRL) and functional capability levels (FCL) are useful metrics for evaluating the readiness of each contributing technology and identifying those technologies that need further development. C1 [Schmalzel, John L.] Rowan Univ, IPA Assignment NASAs John C Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. [Figueroa, Fernando] NASA, EA41, Sci Technol Dirextorate, Stennis Space Ctr, MS 39529 USA. Jacobs Technol, Stennis Space Ctr, MS USA. [Mandayam, Shreekanth A.] Rowan Univ, ECE Dept, Glassboro, NJ USA. RP Schmalzel, JL (reprint author), Rowan Univ, IPA Assignment NASAs John C Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA.; Schmalzel, JL (reprint author), NASA, EA41, Sci Technol Dirextorate, Stennis Space Ctr, MS 39529 USA. EM John.L.Schmalzel@nasa.gov FU NASA FX Manuscript received November 15, 2007. This work was supported in part by NASA; the opinions expressed in this paper are those of the authors and are not to be construed as those ofNASA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1091-5281 BN 978-1-4244-1540-3 J9 IEEE IMTC P PY 2008 BP 522 EP + DI 10.1109/IMTC.2008.4547091 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BIP18 UT WOS:000261512100099 ER PT B AU Anghel, A Astilean, A Letia, T Komjathy, A AF Anghel, Adela Astilean, Adina Letia, Tiberiu Komjathy, Attila BE Miclea, L Stoian, I TI Near real-time monitoring of the ionosphere using dual frequency GPS data in a Kalman filter approach SO 2008 IEEE INTERNATIONAL CONFERENCE ON AUTOMATION, QUALITY AND TESTING, ROBOTICS (AQTR 2008), THETA 16TH EDITION, VOL II, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Automation, Quality and Testing, Robotics (AQTR 2008) CY MAY 22-25, 2008 CL Cluj Napoca, ROMANIA SP IEEE Comp Soc, TTTC ID TOTAL ELECTRON-CONTENT AB The ionosphere is an important source of errors for the GPS signals that travel through the ionosphere on their way to the ground-based receivers by introducing a frequency dependent path delay proportional to the total electron content (TEC) along the signal path. For dual-frequency GPS receivers, the ionospheric effects can be accounted for by taking advantage of the dispersive nature of the ionosphere in the microwave region of the electromagnetic spectrum, while for the single frequency GPS receivers the ionospheric effects can be minimized by modeling them using, for example, empirical or physics-based ionospheric models. On the other hand, the errors imposed by the ionosphere on the GPS signals can provide important temporal and spatial information about the electron density distribution in the ionosphere. Besides the ionospheric errors, there are some other sources of errors that can affect the GPS signals, such as the satellite and receiver instrumental biases, carrier phase ambiguities, multipath effects, clock errors, orbital errors, tropospheric errors, but which can be compensated for, estimated, or neglected depending on the particular application. In this paper, we are only concerned with the ionospheric effects on the GPS signals, and describe a Kalman filter-based algorithm for near real-time estimation of the line-of-sight and vertical ionospheric TEC and of the combined satellite and receiver instrumental biases, using data from dual-frequency GPS receivers. C1 [Anghel, Adela] Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. [Anghel, Adela] Space Weather Predict Ctr, Natl Ocean & Atmospher Admn, Boulder, CO 80309 USA. [Astilean, Adina; Letia, Tiberiu] Tech Univ, Dept Comp Sci & Automat, Cluj Napoca, Romania. [Komjathy, Attila] CALTECH, NASA Jet Propuls Lab, Pasadena, CA USA. RP Anghel, A (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. FU NSF [0207992] FX Funding to carry out this study came from an NSF Space Weather grant, ATM#0207992. NR 14 TC 1 Z9 1 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2576-1 PY 2008 BP 54 EP + DI 10.1109/AQTR.2008.4588793 PG 3 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA BIF22 UT WOS:000259080000004 ER PT S AU Bodine, EA Cheng, MK AF Bodine, Elizabeth A. Cheng, Michael K. GP IEEE TI Characterization of Luby Transform codes with small message size for low-latency decoding SO 2008 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, PROCEEDINGS, VOLS 1-13 SE IEEE International Conference on Communications LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC 2008) CY MAY 19-23, 2008 CL Beijing, PEOPLES R CHINA SP IEEE, Chinese Inst Elect, Chinese Inst Commun, Tsinghu Univ, Beijing Univ, Posts & Telecommun AB Luby Transform (LT) codes provide efficient erasure protection for information distributed across a multi-user channel with unknown characteristics. For real-time applications, however, the random selection of information symbols within a large message can increase encoding and decoding latency beyond allowable parameters. By using a smaller message size, the encoder can generate a codeword at a faster rate, leading to a higher decoder throughput. We decrease decoding latency by optimizing various parameters of the Robust Soliton distribution. This optimization in terms of delay does not lead to minimizing overhead. However, if a small increase in overhead can be tolerated, particularly for a smaller message size, then the overall encoding and decoding delay can be greatly reduced. C1 [Bodine, Elizabeth A.; Cheng, Michael K.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bodine, EA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM eabodine@caltech.edu; mkcheng@jpl.nasa.gov NR 6 TC 19 Z9 22 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1550-3607 BN 978-1-4244-2074-2 J9 IEEE ICC PY 2008 BP 1195 EP 1199 DI 10.1109/ICC.2008.233 PG 5 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BIH49 UT WOS:000259505000225 ER PT S AU Yao, JT Yao, YY Kreinovich, V da Silva, PP Starks, SA Xiang, G Nguyen, HT AF Yao, JingTao Yao, Yiyu Kreinovich, Vladik da Silva, Paulo Pinheiro Starks, Scott A. Xiang, Gang Nguyen, Hung T. GP IEEE TI Towards More Adequate Representation of Uncertainty: From Intervals to Set Intervals, with the Possible Addition of Probabilities and Certainty Degrees SO 2008 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOLS 1-5 SE IEEE International Conference on Fuzzy Systems LA English DT Proceedings Paper CT IEEE International Conference on Fuzzy Systems CY JUN 01-06, 2008 CL Hong Kong, PEOPLES R CHINA SP IEEE ID EXPERT-SYSTEMS AB In the ideal case of complete knowledge, for each property P-i (such as "high fever", "headache", etc.), we know the exact set S-i of all the objects that satisfy this property. In practice, we usually only have partial knowledge. In this case, we only know the set S-i of all the objects about which we know that P-i holds and the set (S) over bar (i) about which we know that P-i may hold (i.e., equivalently, that we have not yet excluded the possibility of P-i). This pair of sets is called a set interval. Based on the knowledge of the original properties, we would like to describe the set S of all the values that satisfy some combination of the original properties: e.g., high fever and headache and not rash. In the ideal case when we know the exact set S-i of all the objects satisfying each property, it is sufficient to apply the corresponding set operation (composition of union, intersection, and complement) to the known sets S-i. In this paper, we describe how to compute the class S of all possible sets S. C1 [Yao, JingTao; Yao, Yiyu] Univ Regina, Dept Comp Sci, Regina, SK S4S 0A2, Canada. [Kreinovich, Vladik; da Silva, Paulo Pinheiro; Starks, Scott A.; Xiang, Gang] Univ Texas, NASA, Pan Amer Ctr Earth & Environm Studies, El Paso, TX USA. [Nguyen, Hung T.] New Mexico State Univ, Dept Math Sci, Las Cruces, NM 88003 USA. RP Yao, JT (reprint author), Univ Regina, Dept Comp Sci, Regina, SK S4S 0A2, Canada. EM jtyao@cs.uregina.ca; yyao@cs.uregina.ca; vladik@utep.edu; hunguyen@nmsu.edu RI Yao, JingTao/A-8483-2008; Yao, Yiyu/B-2926-2008 OI Yao, JingTao/0000-0002-7823-4136; Yao, Yiyu/0000-0001-6502-6226 FU NSF [HRD-0734825, EAR-0225670, EIA-0080940]; Texas Department of Transportation [0-5453]; Japan Advanced Institute of Science and Technology (JAIST) International Joint Research; Max Planck Institut fur Mathematik FX This work was supported in part by NSF grants HRD-0734825, EAR-0225670, and EIA-0080940, by Texas Department of Transportation grant No. 0-5453, by the Japan Advanced Institute of Science and Technology (JAIST) International Joint Research Grant 2006-08, and by the Max Planck Institut fur Mathematik. NR 8 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1098-7584 BN 978-1-4244-1818-3 J9 IEEE INT CONF FUZZY PY 2008 BP 983 EP + DI 10.1109/FUZZY.2008.4630489 PG 2 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIU85 UT WOS:000262974000156 ER PT S AU Johnson, AE Goldberg, SB Cheng, Y Matthies, LH AF Johnson, Andrew E. Goldberg, Steven B. Cheng, Yang Matthies, Larry H. GP IEEE TI Robust and efficient stereo feature tracking for visual odometry SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB Visual odometry can augment or replace wheel odometry when navigating in high slip terrain which is quite important for autonomous navigation on Mars. We present a computationally efficient and robust visual odometry algorithm developed for the Mars Science Laboratory mission. This algorithm is a significant improvement over the algorithm developed for the Mars Exploration Rover Mission because it is at least four time more computationally efficient and it tracks significantly more features. The core of the algorithm is an integrated motion estimation and stereo feature tracking loop that allows for feature recovery while guiding feature correlation search to minimize computation. Results on thousands of terrestrial and Martian stereo pairs show that the algorithm can operate with no initial motion estimate while still obtaining subpixel attitude estimation performance. C1 [Johnson, Andrew E.; Cheng, Yang; Matthies, Larry H.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Goldberg, Steven B.] Ind Syst Inc, Northridge, CA 91324 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM aej@jpl.nasa.gov; indeliblesteve@gmail.com; ycheng@jpl.nasa.gov; lhm@jpl.nasa.gov NR 11 TC 34 Z9 38 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 39 EP + DI 10.1109/ROBOT.2008.4543184 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095000007 ER PT S AU Badescu, M Stroescu, S Sherrit, S Aldrich, J Bao, X Bar-Cohen, Y Chang, Z Hernandez, W Ibrahim, A AF Badescu, M. Stroescu, S. Sherrit, S. Aldrich, J. Bao, X. Bar-Cohen, Y. Chang, Z. Hernandez, W. Ibrahim, A. GP IEEE TI Rotary hammer ultrasonic/sonic drill system SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB Subsurface sampling systems for future planetary robotic missions which include reliable methods of generating, acquiring, and delivering samples to a scientific instrument for analysis are of extreme importance to the success of future insitu and sample return missions. Operating at remote locations the sampler needs to deal with a variety of disparate rock sources while being essential to deliver samples in different forms and to accommodate the requirements of a wide range of scientific instruments. Existing highly efficient terrestrial drilling techniques have limited space applications due to their need for large axial forces and holding torques, high power consumption and inability to efficiently duty cycle, and the use of rigid handling platforms. This paper describes the work performed at Jet Propulsion Laboratory (JPL) and Honeybee Robotics for the development of a rotary percussive drill that uses an ultrasonic/sonic drill/corer as the hammering device integrated in a sampling system capable of automatic operation in a Mars environment. C1 [Badescu, M.; Sherrit, S.; Aldrich, J.; Bao, X.; Bar-Cohen, Y.; Chang, Z.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Stroescu, S.; Hernandez, W.; Ibrahim, A.] Honeybee Robot Spacecraft Mechanisms Corp, New York, NY 10001 USA. RP Badescu, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Mircea.Badescu@jpl.nasa.gov NR 9 TC 4 Z9 4 U1 1 U2 9 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 602 EP + DI 10.1109/ROBOT.2008.4543272 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095000095 ER PT S AU Gaines, DM Estlin, T Chouinard, C AF Gaines, Daniel M. Estlin, Tara Chouinard, Caroline GP IEEE TI Spatial coverage planning for a planetary rover SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB We are developing onboard planning and execution technologies to support the exploration and characterization of geological features by autonomous rovers. In order to generate high quality mission plans, an autonomous rover must reason about the relative importance of the observations it can perform. In this paper we look at the scientific criteria of selecting observations that improve the quality of the area covered by samples. Our approach makes use of a priori information, if available, and allows scientists to mark sub-regions of the area with relative priorities for exploration. We use an efficient algorithm for prioritizing observations based on spatial coverage that allows the system to update observation rankings as new information is gained during execution. C1 [Gaines, Daniel M.; Estlin, Tara; Chouinard, Caroline] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaines, DM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 614 EP 620 DI 10.1109/ROBOT.2008.4543274 PG 7 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095000097 ER PT S AU Thompson, DR Smith, T Wettergreen, D AF Thompson, David R. Smith, Trey Wettergreen, David GP IEEE TI Information-optimal selective data return for autonomous rover traverse science and survey SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB Selective data return leverages onboard data analysis to allocate limited bandwidth resources during remote exploration. Here we present an adaptive method to subsample image sequences for downlink. We treat selective data return as a compression problem in which the explorer agent transmits the subset of measurements that are most informative with respect to the complete dataset. Experiments demonstrate selective downlink of navigation imagery by a rover during autonomous geologic investigations in the Atacama desert of Chile. Here automatic analysis identifies informative images using classifications based on natural image statistics. Image texture analysis, together with a context-sensitive Hidden Markov Model representation, permits adaptive downlink in response to geologic unit boundaries. Selective data return improves the science content of returned data for this geologic mapping task. C1 [Thompson, David R.; Wettergreen, David] Carnegie Mellon Univ, Inst Robot, 5000 Forbes Ave, Pittsburgh, PA 15213 USA. [Smith, Trey] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Thompson, DR (reprint author), Carnegie Mellon Univ, Inst Robot, 5000 Forbes Ave, Pittsburgh, PA 15213 USA. EM drt@ri.cmu.edu; trey.smith@west.cmu.edu; dsw@ri.cmu.edu FU NASA [NNG0-4GB66G] FX The authors thank the Life in the Atacama project teamincluding Dominic Jonak and Michael Wagner, and the science team for their assistance with geologic interpretatio ns. NASA ASTEP grant NNG0-4GB66G supported the work. NR 22 TC 3 Z9 4 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 968 EP + DI 10.1109/ROBOT.2008.4543330 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095000153 ER PT S AU Podnar, GW Dolan, JM Elfes, A Stancliff, S Lin, E Hosler, JC Ames, TJ Moisan, J Moisan, TA Higinbotham, J Kulczycki, EA AF Podnar, Gregg W. Dolan, John M. Elfes, Alberto Stancliff, Stephen Lin, Ellie Hosler, Jeffrey C. Ames, Troy J. Moisan, John Moisan, Tiffany A. Higinbotham, John Kulczycki, Eric A. GP IEEE TI Operation of robotic science boats using the Telesupervised Adaptive Ocean Sensor Fleet system SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB This paper describes a multi-robot science exploration software architecture and system called the Telesupervised Adaptive Ocean Sensor Fleet (TAOSF). TAOSF supervises and coordinates a group of robotic boats, the OASIS platforms, to enable in situ study of phenomena in the ocean/atmosphere interface, as well as on the ocean surface and sub-surface. The OASIS platforms are extended-deployment autonomous ocean surface vessels, whose development is funded separately by the National Oceanic and Atmospheric Administration (NOAA). TAOSF allows a human operator to effectively supervise and coordinate multiple robotic assets using a multi-level autonomy control architecture, where the operating mode of the vehicles ranges from autonomous control to teleoperated human control. TAOSF increases data-gathering effectiveness and science return while reducing demands on scientists for robotic asset tasking, control, and monitoring. The first field application chosen for TAOSF is the characterization of Harmful Algal Blooms (HABs). We discuss the overall TAOSF architecture, describe field tests conducted under controlled conditions using rhodamine dye as a HAB simulant, present initial results from these tests, and outline the next steps in the development of TAOSF. C1 [Elfes, Alberto; Kulczycki, Eric A.] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. [Podnar, Gregg W.; Dolan, John M.; Elfes, Alberto; Stancliff, Stephen; Lin, Ellie] Carnegie Mellon Univ, Inst Robot, Pittsburgh, PA 15213 USA. [Hosler, Jeffrey C.; Ames, Troy J.] NASA, Goddard Space Flight Facil, Greenbelt, MD 20771 USA. [Moisan, John; Moisan, Tiffany A.] NASA, Wallops Flight Facil, Wallops Isl, VA 23337 USA. [Higinbotham, John] Emergent Space Technol, Greenbelt, MD 20770 USA. [Kulczycki, Eric A.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Elfes, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM gwp@cs.cmu.edu; jmd@cs.cmu.edu; elfes@jpl.nasa.gov; stancliff@cmu.edu; elliel@andrew.cmu.edu; Jeffrey.C.Hosler@nasa.gov; troyj.ames@nasa.gov; john.moisan@gsfc.nasa.gov; tmoisan@osb1.wffnasa.gov; john.higinbotham@emergentspace.com; eric.a.kulczycki@jpl.nasa.gov RI Elfes, Alberto/E-2463-2011; Moisan, John/B-8762-2016 OI Elfes, Alberto/0000-0003-2433-995X; Moisan, John/0000-0002-8078-8939 FU NASA "Telesupervised Adaptive Ocean Sensor Fleet" - Advanced Information Systems Technology program of NASA's Earth Systems Technology Office (ESTO) [NNX06AF27G]; Zinger Enterprises under award from the National Oceanic and Atmospheric Administration (NOAA) [NA03NOS4730220] FX This work was supported by NASA award NNX06AF27G, Telesupervised Adaptive Ocean Sensor Fleet, granted under the Advanced Information Systems Technology program of NASAs Earth Systems Technology Office (ESTO. The TAOSF project is a collaboration among Carnegie Mellon University (CMU), NASA Goddard Space Flight Center (GSFC), NASA Goddards Wallops Flight Facility (WFF), Emergent Space Technologies, Inc. (EST), and the Jet Propulsion Laboratory (JPL). Work on the OASIS platforms is conducted by Emergent Space Technologies, Inc., EG&G, and Zinger Enterprises under award NA03NOS4730220 from the National Oceanic and Atmospheric Administration (NOAA), U.S. Department of Commerce. NR 12 TC 8 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 1061 EP + DI 10.1109/ROBOT.2008.4543345 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095000168 ER PT S AU Matthies, L Huertas, A Cheng, Y Johnson, A AF Matthies, Larry Huertas, Andres Cheng, Yang Johnson, Andrew GP IEEE TI Stereo vision and shadow analysis for landing hazard detection SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB Unmanned planetary landers to date have landed "blind", without the benefit of onboard landing hazard detection and avoidance systems. This constrains landing sites to very benign terrain and limits the scientific goals of missions. We review sensor options for landing hazard detection, then identify an approach based on stereo vision and shadow analysis that appears to address the broadest set of missions with the lowest cost. We describe algorithms for slope estimation and rock detection with this approach, develop models of their performance, and validate those models experimentally. Instantiating our model of rock detection reliability for Mars predicts that this approach would reduce the probability of failed landing by at least a factor of 4 compared to blind landing. Conversely, for the safety level desired for the 2009 Mars lander, this approach would increase the fraction of the planet that is accessible for landing from about 1/3 to nearly 100%. C1 [Matthies, Larry; Huertas, Andres; Cheng, Yang; Johnson, Andrew] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matthies, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 8 Z9 10 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 2735 EP 2742 DI 10.1109/ROBOT.2008.4543625 PG 8 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095002003 ER PT S AU Marks, TK Howard, A Bajracharya, M Cottrell, GW Matthies, L AF Marks, Tim K. Howard, Andrew Bajracharya, Max Cottrell, Garrison W. Matthies, Larry GP IEEE TI Gamma-SLAM: Using stereo vision and variance grid maps for SLAM in unstructured environments SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB We introduce a new method for stereo visual SLAM (simultaneous localization and mapping) that works in unstructured, outdoor environments. Unlike other grid-based SLAM algorithms, which use occupancy grid maps, our algorithm uses a new mapping technique that maintains a posterior distribution over the height variance in each cell. This idea was motivated by our experience with outdoor navigation tasks, which has shown height variance to be a useful measure of traversability. To obtain a joint posterior over poses and maps, we use a Rao-Blackwellized particle filter: the pose distribution is estimated using a particle filter, and each particle has its own map that is obtained through exact filtering conditioned on the particle's pose. Visual odometry provides good proposal distributions for the particle pose. In the analytical (exact) filter for the map, we update the sufficient statistics of a gamma distribution over the precision (inverse variance) of heights in each grid cell. We verify the algorithm's accuracy on two outdoor courses by comparing with ground truth data obtained using electronic surveying equipment. In addition, we solve for the optimal transformation from the SLAM map to georeferenced coordinates, based on a noisy GPS signal. We derive an online version of this alignment process, which can be used to maintain a running estimate of the robot's global position that is much more accurate than the GPS readings. C1 [Marks, Tim K.; Cottrell, Garrison W.] Univ Calif San Diego, Dept Comp Sci & Engn, La Jolla, CA 92093 USA. [Howard, Andrew; Bajracharya, Max; Matthies, Larry] NASA, Jet Prop Lab, Pasadena, CA USA. RP Marks, TK (reprint author), Univ Calif San Diego, Dept Comp Sci & Engn, La Jolla, CA 92093 USA. EM tkmarks@cs.ucsd.edu; abhoward@robotics.jpl.nasa.gov; maxb@robotics.jpl.nasa.gov; gary@cs.ucsd.edu; lhm@robotics.jpl.nasa.gov FU DARPA LAGR program through an agreement; National Aeronautics and Space Administration; NSF [SBE-0542013] FX This work was performed for the Jet Propulsion Laboratory, California Institute of Technology, and was sponsored by the DARPA LAGR program through an agreement with the National Aeronautics and Space Administration. GWC is supported in part by NSF grant SBE-0542013. NR 16 TC 9 Z9 9 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 3717 EP + DI 10.1109/ROBOT.2008.4543781 PG 2 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095002159 ER PT S AU Bajracharya, M Tang, B Howard, A Turmon, M Matthies, L AF Bajracharya, Max Tang, Benyang Howard, Andrew Turmon, Michael Matthies, Larry GP IEEE TI Learning long-range terrain classification for autonomous navigation SO 2008 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-9 SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 19-23, 2008 CL Pasadena, CA SP IEEE AB This paper describes a method for learning the terrain classification of long-range appearance data from short-range, stereo-based geometry, along with a map representation for utilizing this data to improve autonomous off-road navigation. The continuous, online learning method allows the system to constantly adapt to changing terrain and environmental conditions, while the polar-perspective map representation allows the system to effectively plan with stereo data at long ranges. Various evaluations of the long-range classification and improvements in system performance are described, including results from an independent third-party testing team. C1 [Bajracharya, Max; Tang, Benyang; Howard, Andrew; Turmon, Michael; Matthies, Larry] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bajracharya, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 14 Z9 15 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 978-1-4244-1646-2 J9 IEEE INT CONF ROBOT PY 2008 BP 4018 EP 4024 DI 10.1109/ROBOT.2008.4543828 PG 7 WC Automation & Control Systems; Robotics SC Automation & Control Systems; Robotics GA BIB31 UT WOS:000258095002206 ER PT B AU Bhasin, KB Hayden, JL AF Bhasin, Kul B. Hayden, Jeffrey L. GP IEEE TI Architecting Communication Network of Networks for Space System of Systems SO 2008 IEEE INTERNATIONAL CONFERENCE ON SYSTEM OF SYSTEMS ENGINEERING (SOSE) LA English DT Proceedings Paper CT IEEE International Conference on System of Systems Engineering CY JUN 02-04, 2008 CL Monterey, CA SP IEEE DE Architecting; space communications; system of systems; SoS; network of networks; NoN; Internet Protocol; IP; DoDAF; architecture framework AB The National Aeronautics and Space Administration (NASA) and the Department of Defense (DoD) are planning Space System of Systems (SoS) to address the new challenges of space exploration, defense, communications, navigation, Earth observation, and science. In addition, these complex systems must provide interoperability, enhanced reliability, common interfaces, dynamic operations, and autonomy in system management. Both NASA and the DoD have chosen to meet the new demands with high data rate communication systems and space Internet technologies that bring Internet Protocols (IP), routers, servers, software, and interfaces to space networks to enable as much autonomous operation of those networks as possible. These technologies reduce the cost of operations' and, with higher bandwidths, support the expected voice, video, and data needed to coordinate activities at each stage of an exploration mission. In this paper, we discuss, in a generic fashion, how the architectural approaches and processes are being developed and used for defining a hypothetical communication and navigation networks infrastructure to support lunar exploration. Examples are given of the products generated by the architecture development process. C1 [Bhasin, Kul B.] NASA, Glenn Res Ctr, Cleveland, OH USA. [Hayden, Jeffrey L.] PresciPoint Solut LLC, Littleton, CO USA. RP Bhasin, KB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. EM Kul.B.Bhasin@nasa.gov; jlhayden@earthlink.net NR 13 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2172-5 PY 2008 BP 129 EP + PG 2 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BJE67 UT WOS:000265213000023 ER PT B AU Wilson, WC Perey, DF Atkinson, GM Barclay, RO AF Wilson, William C. Perey, Daniel F. Atkinson, Gary M. Barclay, Rebecca O. GP IEEE TI Passive Wireless SAW Sensors for IVHM SO 2008 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 19-21, 2008 CL Honolulu, HI SP IEEE ID ACOUSTIC-WAVE DEVICES AB NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to he small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology. C1 [Wilson, William C.; Perey, Daniel F.] NASA, Nondestruct Evaluat Branch, Langley Res Ctr, Hampton, VA 23681 USA. [Atkinson, Gary M.] Virginia Commonwealth Univ, Elect & Comp Engn, Richmond, VA 23284 USA. [Barclay, Rebecca O.] Christopher Newport Univ, Dept English, Newport News, VA 23606 USA. RP Wilson, WC (reprint author), NASA, Nondestruct Evaluat Branch, Langley Res Ctr, Hampton, VA 23681 USA. EM gmatkins@vcu.edu FU NASA Integrated Vehicle Heath Management (IVHM); Aeronautics Research Mission Directorate (ARMD) FX This work is funded by NASA Integrated Vehicle Heath Management (IVHM) Project which is part of the Aviation Safety Program under the Aeronautics Research Mission Directorate (ARMD). NR 38 TC 4 Z9 4 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1794-0 PY 2008 BP 273 EP + DI 10.1109/FREQ.2008.4623003 PG 3 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIO06 UT WOS:000261285400058 ER PT B AU Burt, EA Taghavi, S Prestage, JD Tjoelker, RL AF Burt, E. A. Taghavi, S. Prestage, J. D. Tjoelker, R. L. GP IEEE TI Stability Evaluation of Systematic Effects in a Compensated Multi-pole Mercury Trapped Ion Frequency Standard SO 2008 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 19-21, 2008 CL Honolulu, HI SP IEEE ID CLOCKS AB A compensated multi-pole Linear Ion Trap Standard (LITS) using trapped Hg-199+ has recently demonstrated a fractional frequency deviation from the laser-cooled primary standards and the post-processed version of TAI known as TT(BIPM) of < 2.7(0.4)x10(-17)/day over a 9-month period. A subsequent stability evaluation performed after the 9-month comparison is in statistical agreement with the measured instability. We will describe the largest remaining sources of instability including a first measurement of the Hg+/Hg pressure shift of +3.8(7.2)x10(-8)/Pa. We also describe initial results using a sealed vacuum system. Finally we are beginning an investigation of Hg-201+ and will describe a proposed frequency comparison between Hg-201+ and Hg-199+ that may be able to place a new limit on fundamental constant variation*. C1 [Burt, E. A.; Taghavi, S.; Prestage, J. D.; Tjoelker, R. L.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Burt, EA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 1 Z9 1 U1 0 U2 5 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1794-0 PY 2008 BP 371 EP 376 DI 10.1109/FREQ.2008.4623022 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIO06 UT WOS:000261285400077 ER PT B AU Prestage, JD Tu, MR Chung, SK MacNeal, P AF Prestage, John D. Tu, Meirong Chung, Sang K. MacNeal, Paul GP IEEE TI Compact Microwave Mercury Ion Clock for Space Applications SO 2008 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 19-21, 2008 CL Honolulu, HI SP IEEE AB We have recently completed a breadboard ion-clock physics package based on Hg ions shuttled between a quadrupole and a 16-pole rf trap. With this architecture we have demonstrated short-term stability similar to 1-2x10(-13) at 1 second, averaging to 10(-15) at 1 day. This development shows that H-maser quality stabilities can be produced in a small clock package, comparable in size to an ultra-stable quartz oscillator required for holding 1-2x10(-13) at 1 second. This performance was obtained in a sealed vacuum configuration where only a getter pump was used to maintain vacuum. The vacuum tube containing the traps has now been under sealed vacuum conditions for nearly three years with no measurable degradation of ion trapping lifetimes or clock short-term performance. We have fabricated the vacuum tube, ion trap and UV windows from materials that will allow a similar to 400 degrees C bake-out to prepare for tube seal-off. This approach to the vacuum follows the methods used in flight vacuum tube electronics, such as flight TWTA's where tube operation lifetime and shelf life of up to 15 years is achieved. C1 [Prestage, John D.; Tu, Meirong; Chung, Sang K.; MacNeal, Paul] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Prestage, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM John.D.Prestage@jpl.nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1794-0 PY 2008 BP 651 EP 654 DI 10.1109/FREQ.2008.4623080 PG 4 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIO06 UT WOS:000261285400135 ER PT B AU Tinto, M AF Tinto, Massimo GP IEEE TI Frequency and Timing Requirements for the LISA Mission SO 2008 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 19-21, 2008 CL Honolulu, HI SP IEEE ID TIME-DELAY INTERFEROMETRY; GRAVITATIONAL-RADIATION; TRACKING AB The Laser Interferometer Space Antenna (LISA) is a deep-space mission, jointly proposed to the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA), to detect and study gravitational radiation in the milliHertz frequency band. LISA will use coherent laser beams exchanged between three remote, widely separated, spacecraft, and onboard frequency standards for measuring phase differences between the received and transmitted laser beams. By properly combining the one-way measurements collected by the three spacecraft it is possible to simultaneously synthesize several interferometric observables. All are independent of the lasers and frequency standards phase fluctuations, but have different couplings to gravitational waves and to the various LISA instrumental noises. An overview or this exciting and technologically challenging deep space mission is presented, with special emphasis on its frequency and timing requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tinto, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Massimo.Tinto@jpl.nasa.gov NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1794-0 PY 2008 BP 801 EP 806 DI 10.1109/FREQ.2008.4623109 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA BIO06 UT WOS:000261285400164 ER PT S AU Chen, XJ Barnaby, HJ Pease, RL Adell, P AF Chen, X. J. Barnaby, H. J. Pease, R. L. Adell, P. GP IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP TI Behavior of radiation-induced defects in bipolar oxides during irradiation and annealing in hydrogen-rich and -depleted ambients SO 2008 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 46TH ANNUAL SE International Reliability Physics Symposium LA English DT Proceedings Paper CT 46th Annual IEEE International Reliability Physics Symposium CY APR 27-MAY 01, 2008 CL Phoenix, AZ SP IEEE Electron Devices Soc, IEEE Reliabil Soc DE oxide charge; interface traps; radiation environment; hydrogen; gated bipolar transistor ID INTERFACE-TRAP FORMATION; MOS DEVICES; MOLECULAR-HYDROGEN; SI-SIO2 INTERFACE; BORDER TRAPS; HARDNESS; ENVIRONMENTS; SIO2 AB The results of this study showed that when excess hydrogen is introduced to gated bipolar devices in the radiation environment, the buildup of radiation-induced defects in device oxides and their annealing behaviors are dramatically changed due to hydrogen. The different annealing behaviors of oxide charge between hydrogen-rich and -depleted devices suggest that the defects contributing to the enhanced oxide charge may be microscopically different from the conventional trapped charge described in literature. C1 [Chen, X. J.; Barnaby, H. J.] Arizona State Univ, Tempe, AZ 85287 USA. [Pease, R. L.] RLP Res, Los Lunas, NM USA. [Adell, P.] Jet Prop Lab, Pasadena, CA USA. RP Chen, XJ (reprint author), Arizona State Univ, Tempe, AZ 85287 USA. FU NASA Electronics Parts Program (NEPP); Air Force Office of Scientific Research; MURI FX This work is support funding from the NASA Electronics Parts Program (NEPP), and the Air Force Office of Scientific Research with funding from the MURI program. irrad NR 25 TC 1 Z9 1 U1 0 U2 2 PU IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1541-7026 BN 978-1-4244-2049-0 J9 INT RELIAB PHY SYM PY 2008 BP 115 EP + DI 10.1109/RELPHY.2008.4558871 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA BHZ18 UT WOS:000257615900017 ER PT S AU Chen, Y Mojarradi, M Westergard, L Aranki, N Kolawa, E Blalock, B AF Chen, Yuan Mojarradi, Mohammad Westergard, Lynett Aranki, Nazeeh Kolawa, Elizabeth Blalock, Benjamin GP IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP TI A case study: Design for reliability for a rail-to-rail operational amplifier for wide temperature range operation for mars missions SO 2008 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 46TH ANNUAL SE International Reliability Physics Symposium LA English DT Proceedings Paper CT 46th Annual IEEE International Reliability Physics Symposium CY APR 27-MAY 01, 2008 CL Phoenix, AZ SP IEEE Electron Devices Soc, IEEE Reliabil Soc DE wide temperature op-amp; low temperature electronics; design for reliability AB A case study is presented applying a design-for-reliability methodology to design, fabricate and qualify a quad rail-to-rail operational amplifier for the wide temperature range operation of -140 degrees C to +125 degrees C to for space applications. The design-for-reliability approach was developed and implemented from transistor level up to board/system level, along with a comprehensive qualification procedure for the wide temperature range. The quad op-amp is used for a flight mission and available from a commercial production line. C1 [Chen, Yuan; Mojarradi, Mohammad; Aranki, Nazeeh; Kolawa, Elizabeth] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. [Westergard, Lynett] AMI Semicond, Pocatello, ID 83201 USA. [Blalock, Benjamin] Univ Tennessee, Integrated Circuits & Syst Lab, Knoxville, TN 37996 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. EM yuan.chen@jpl.nasa.gov NR 10 TC 1 Z9 1 U1 0 U2 0 PU IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1541-7026 BN 978-1-4244-2049-0 J9 INT RELIAB PHY SYM PY 2008 BP 121 EP + PG 2 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA BHZ18 UT WOS:000257615900018 ER PT S AU Chen, Y Del Castillo, L Aranki, N Assad, C Mazzola, M Mojarradi, M Kolawa, E AF Chen, Yuan Del Castillo, Linda Aranki, Nazeeh Assad, Chris Mazzola, Mike Mojarradi, Mohammad Kolawa, Elizabeth GP IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP TI Reliability assessment of high temperature electronics and packaging technologies for Venus Mission SO 2008 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 46TH ANNUAL SE International Reliability Physics Symposium LA English DT Proceedings Paper CT 46th Annual IEEE International Reliability Physics Symposium CY APR 27-MAY 01, 2008 CL Phoenix, AZ SP IEEE Electron Devices Soc, IEEE Reliabil Soc C1 [Chen, Yuan; Del Castillo, Linda; Aranki, Nazeeh; Assad, Chris; Mazzola, Mike; Mojarradi, Mohammad; Kolawa, Elizabeth] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. NR 2 TC 4 Z9 4 U1 0 U2 0 PU IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1541-7026 BN 978-1-4244-2049-0 J9 INT RELIAB PHY SYM PY 2008 BP 641 EP + PG 2 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA BHZ18 UT WOS:000257615900113 ER PT B AU Scheick, L Selva, L Chen, Y Edmonds, L AF Scheick, Leif Selva, Luis Chen, Yuan Edmonds, Larry GP IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP TI Current leakage evolution in partially gate-ruptured power MOSFETs SO 2008 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 46TH ANNUAL SE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM LA English DT Proceedings Paper CT 46th Annual IEEE International Reliability Physics Symposium CY APR 27-MAY 01, 2008 CL Phoenix, AZ SP IEEE Electron Devices Soc, IEEE Reliabil Soc ID SEGR; ENERGY AB The range of resulting leakage from single-event gate rupture (SEGR) in power MOSFETs spans several decades, from hundreds of nanoamps to tens of milliamps being qualified as rupture events. The differences in the magnitude of the breaks are correlated to the physical and operational effects of the devices investigated. The maximum leakage current that a part may endure and not destroy itself is determined experimentally and analytically. C1 [Scheick, Leif; Selva, Luis; Chen, Yuan; Edmonds, Larry] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scheick, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2049-0 J9 INT REL PHY PY 2008 BP 645 EP 646 DI 10.1109/RELPHY.2008.4558968 PG 2 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA BHZ18 UT WOS:000257615900115 ER PT B AU Laird, JS Chen, Y AF Laird, J. S. Chen, Y. GP IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP TI Picosecond laser microscopy for investigating localization of alpha particle induced soft error rates in deep submicron CMOS VLSI SO 2008 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS - 46TH ANNUAL SE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM LA English DT Proceedings Paper CT 46th Annual IEEE International Reliability Physics Symposium CY APR 27-MAY 01, 2008 CL Phoenix, AZ SP IEEE Electron Devices Soc, IEEE Reliabil Soc DE alpha particle; soft error rate; picosecond laser microscopy; deep-submicron CMOS; charge sharing ID CHARGE COLLECTION; PULSED-LASER C1 [Laird, J. S.; Chen, Y.] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Laird, JS (reprint author), CALTECH, Jet Prop Lab, 4800 Oakgrove Dr, Pasadena, CA 91109 USA. EM Jamie.S.Laird@jpl.nasa.gov RI Laird, Jamie/A-7683-2011 NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2049-0 J9 INT REL PHY PY 2008 BP 731 EP 732 DI 10.1109/RELPHY.2008.4559011 PG 2 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA BHZ18 UT WOS:000257615900158 ER PT B AU Nguyen, TX Melnik, JJ AF Nguyen, Truong X. Melnik, John J. GP IEEE TI Radio Frequency Compatibility of an RFID Tag on Glideslope Navigation Receivers SO 2008 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, VOLS 1-3 LA English DT Proceedings Paper CT IEEE International Symposium on Electromagnetic Compatibility CY AUG 18-22, 2008 CL Detroit, MI SP IEEE DE interference threshold; RFID; aircraft; glideslope; navigation; interference path loss AB A process is demonstrated to show compatibility between a radio frequency identification (RFID) tag and an aircraft glideslope (GS) radio receiver. The particular tag chosen was previously shown to have significant peak spurious emission levels that far exceeded the emission limits in the GS aeronautical band. The spurious emissions are emulated in the study by capturing the RFID fundamental transmission and playing back the signal in the GS band. The signal capturing and playback are achieved with a vector signal generator and a spectrum analyzer that can output the in-phase and quadrature components (IQ). The simulated interference signal is combined with a desired GS signal before being injected into a GS receiver's antenna port for interference threshold determination. Minimum desired propagation loss values to avoid interference are then computed and compared against actual propagation losses for several aircraft. C1 [Nguyen, Truong X.] NASA, Langley Res Ctr, Hampton, VA 23665 USA. [Melnik, John J.] Lockheed Martin Corp, Hampton, VA 23666 USA. RP Nguyen, TX (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM Truong.x.nguyen@nasa.gov NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1699-8 PY 2008 BP 502 EP + PG 2 WC Engineering, Electrical & Electronic SC Engineering GA BIW65 UT WOS:000263416300093 ER PT B AU Dolinar, S Andrews, K Pollara, F Divsalar, D AF Dolinar, Sam Andrews, Kenneth Pollara, Fabrizio Divsalar, Dariush GP IEEE TI The Limits of Coding with Joint Constraints on Detected and Undetected Error Rates SO 2008 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY PROCEEDINGS, VOLS 1-6 LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUL 06-11, 2008 CL Toronto, CANADA SP IEEE, RIM, Ontario Cent Excellence, IBM Res, Microsoft Res ID DECODING ERROR; PROBABILITY; BOUNDS; CODES AB We develop a remarkably tight upper bound on the performance of a parameterized family of bounded angle maximum-likelihood (BA-ML) incomplete decoders. The new bound for this class of incomplete decoders is calculated from the code's weight enumerator, and is an extension of Poltyrev-type bounds developed for complete ML decoders. This bound can also be applied to bound the average performance of random code ensembles in terms of an ensemble average weight enumerator. We also formulate conditions defining a parameterized family of optimal incomplete decoders, defined to minimize both the total codeword error probability and the undetected error probability for any fixed capability of the decoder to detect errors. We illustrate the gap between optimal and BA-ML incomplete decoding via simulation of a small code. C1 [Dolinar, Sam; Andrews, Kenneth; Pollara, Fabrizio; Divsalar, Dariush] CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Dolinar, S (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA USA. EM sam@shannon.jpl.nasa.gov; andrews@shannon.jpl.nasa.gov; fabrizio@shannon.jpl.nasa.gov; dariush@shannon.jpl.nasa.gov NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2256-2 PY 2008 BP 970 EP 974 DI 10.1109/ISIT.2008.4595131 PG 5 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIK25 UT WOS:000260364400196 ER PT B AU Klimesh, M AF Klimesh, Matthew GP IEEE TI Redundancy and Optimality of Codes for Infinite-Entropy Sources SO 2008 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY PROCEEDINGS, VOLS 1-6 LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUL 06-11, 2008 CL Toronto, CANADA SP IEEE, RIM, Ontario Cent Excellence, IBM Res, Microsoft Res ID HUFFMAN; BOUNDS AB Redundancy and optimatity are standard concepts for prefix codes for finite-entropy sources, but they can be extended to codes for (discrete) infinite-entropy sources as well. Here three redundancy definitions and two optimality definitions are considered that accomplish this. The redundancy definitions turn out to be equivalent, and they are also equivalent to the 'expected codeword length minus entropy' definition when the source entropy is finite. An analogous statement holds for the optimality definitions. A theorem on the redundancy of finite sources is also presented; it provides a simple bound on the difference between the redundancies of optimal codes for two sources that contain an identical subset of symbol probabilities. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Klimesh, M (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA USA. EM matthew.a.klimesh@jpl.nasa.gov NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-2256-2 PY 2008 BP 1949 EP 1953 DI 10.1109/ISIT.2008.4595329 PG 5 WC Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BIK25 UT WOS:000260364401112 ER PT B AU Zhouo, S Van Aartsen, BH Clune, TL AF Zhouo, Shujia Van Aartsen, Bruce H. Clune, Thomas L. GP IEEE TI A lightweight scalable I/O utility for optimizing High-End Computing applications SO 2008 IEEE INTERNATIONAL SYMPOSIUM ON PARALLEL & DISTRIBUTED PROCESSING, VOLS 1-8 LA English DT Proceedings Paper CT 22nd IEEE International Parallel and Distributed Processing Symposium (IPDPS 2008) CY APR 14-18, 2008 CL Miami, FL SP IEEE ID MODEL COUPLING TOOLKIT AB Filesystem I/O continues to be a major performance bottleneck for many High-End Computing (HEC) applications and in particular for Earth science models, which often generate a relatively large volume of data for a given amount of computational work. The severity of this I/O bottleneck rapidly increases with the number of processors utilized. Consequently, considerable computing resources are wasted, and the sustained Performance of HEC applications such as climate and weather models is highly constrained. To alleviate much of this bottleneck, we have developed a lightweight software utility designed to improve performance of typical scientific applications by circumventing bandwidth limitations of typical HEC filesystems. The approach is to exploit the faster interprocessor bandwidth to move output data from compute nodes to designated I/O nodes as quickly as possible, thereby minimizing the I/O wait time. This utility has successfully demonstrated a significant performance improvement within a major NASA weather application. C1 [Zhouo, Shujia; Van Aartsen, Bruce H.; Clune, Thomas L.] NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zhouo, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1693-6 PY 2008 BP 2922 EP 2928 PG 7 WC Computer Science, Theory & Methods SC Computer Science GA BID12 UT WOS:000258501402014 ER PT B AU Saini, S Jespersen, DC Talcott, D Djomehri, J Sandstrom, T AF Saini, Subhash Jespersen, Dennis C. Talcott, Dale Djomehri, Jahed Sandstrom, Timothy GP IEEE TI Performance comparison of SGI Altix 4700 and SGI Altix 3700 Bx2 SO 2008 IEEE INTERNATIONAL SYMPOSIUM ON PARALLEL & DISTRIBUTED PROCESSING, VOLS 1-8 LA English DT Proceedings Paper CT 10th Workshop on Advances in Parallel and Distributed Computational Models/22nd IEEE International Parallel and Distributed Processing Symposium CY APR 14-18, 2008 CL Miami, FL SP IEEE AB Suitability of the next generation of high-performance computing systems for petascale simulations will depend on a balance between factors such as processor performance, memory performance, local and global network performance, and Input/Output (RO) performance. As the supercomputing industry develops new technologies for these subsystems, achieving system balance becomes challenging. In this paper, we evaluate the performance of a newly introduced dual-core-based SGI Altix 4700 system and we compare its performance with that of a single-core-based SGI Altix 3700 Bx2 system. We used the High-Performance Computing Challenge (HPCC) benchmarks and five real-world applications, three from computational fluid dynamics, one from climate modeling and one from nanotechnology. Our study shows that the SGI Altix 4700 performs slightly better than the SGI Altix 3700 Bx2 up to 128 processors, while the performance of the systems is almost the same beyond 128 processors, when the communication time dominates the compute time. C1 [Saini, Subhash; Jespersen, Dennis C.; Talcott, Dale; Djomehri, Jahed; Sandstrom, Timothy] NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. RP Saini, S (reprint author), NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. EM Subhash.Saini@nasa.gov; Dennis.C.Jespersen@nasa.gov; Dale.R.Talcott@nasa.gov; Mohammad.J.Djomehri@nasa.gov; Timothy.A.Sandstrom@nasa.gov NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 978-1-4244-1693-6 PY 2008 BP 3182 EP 3189 PG 8 WC Computer Science, Theory & Methods SC Computer Science GA BID12 UT WOS:000258501402047 ER EF