FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Cabrol, NA Grin, EA AF Cabrol, NA Grin, EA TI Overview on the formation of paleolakes and ponds on Mars SO GLOBAL AND PLANETARY CHANGE LA English DT Article; Proceedings Paper CT Symposium on Subglacial Lakes CY 2001 CL SAN FRANCISCO, CALIFORNIA DE paleolake; Mars; ponds ID MARTIAN OUTFLOW CHANNELS; IMPACT CRATER LAKES; ORIGIN; ICE; SURFACE; EARTH; WATER; ATMOSPHERE; DEPOSITS; EROSION AB Lakes on Mars were formed under periglacial to glacial climates. Extreme conditions prevailed including freezing temperatures, low atmospheric pressure, high evaporation/sublimation rates, and liquid water reservoirs locked in aquifers below a thick cryosphere. Although many of the Martian paleolakes display evidence of a short period of activity consistent with these conditions, others display clear evidence of lifetimes ranging from 10(4) to 10(5) years. The discovery of young seeping processes in impact craters and pole-facing valley slopes along with young volcanic activity raise questions about the conditions and limitations of liquid water flow and potential lacustrine activity today on Mars. Current climate models show that in today's conditions there exist regions on Mars of sols above the triple point and below boiling point of water that could provide hydrogeological conditions comparable to these of the Antarctic Dry Valley lakes (with the exception of the atmosphere pressure). The locations of the most recent Martian paleolakes are correlated with these regions. Throughout the history of Mars, lakes generated diversified environments, which could have provided potential habitats for life. The recent discovery of young energy sources from volcanism and the potential for liquid water reinforces the possibility of extant life on Mars, and suggests recent ponds and ancient paleolakes as primary targets for rover and sample return missions. (C) 2002 Elsevier Science B.V All rights reserved. C1 NASA, Ames Res Ctr, SETI Inst, Div Space Sci, Moffett Field, CA 94035 USA. RP Cabrol, NA (reprint author), NASA, Ames Res Ctr, SETI Inst, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. NR 111 TC 9 Z9 10 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD FEB PY 2003 VL 35 IS 3-4 BP 199 EP 219 AR PII S0921-8181(02)00127-3 DI 10.1016/S0921-8181(02)00127-3 PG 21 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 634XA UT WOS:000180366700005 ER PT J AU Nakagawa, M Agui, JH Wu, DT Extramiana, DV AF Nakagawa, M Agui, JH Wu, DT Extramiana, DV TI Impulse dispersion in a tapered granular chain SO GRANULAR MATTER LA English DT Article; Proceedings Paper CT Meeting on Behaviour of Granular Materials CY FEB 22, 2002 CL UNIV LEEDS, LEEDS, ENGLAND SP Univ Inst Particle Sci & Engn HO UNIV LEEDS DE tapered granular chain; impulse; dispersion; experiment ID SOUND-PROPAGATION; BEADS; SAND AB This paper describes a unique way to disperse an impulse in granular material. A number of chrome steel balls are arranged in a chain formation with monotonically decreasing size. The incoming impulse is received by the largest ball at one end and propagates through the chain. Due to translation symmetry breaking, the classical solitary wave known to develop in a chain of particles of the same size quickly lose its signature, disperses itself throughout the balls in the chain, and finally manifests itself as a collection of smaller impulses. This paper presents experimental confirmation of this mechanism and a comparison with recent theoretical predictions of impulse dispersion in a chain of hard inelastic spheres. Some discrepancies with theory are interpreted in terms of energy transfer to rotational degrees of freedom. C1 Colorado Sch Mines, Dept Min Engn, Golden, CO 80401 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Colorado Sch Mines, Dept Chem Engn, Golden, CO 80401 USA. Colorado Sch Mines, Dept Chem, Golden, CO 80401 USA. RP Nakagawa, M (reprint author), Colorado Sch Mines, Dept Min Engn, Golden, CO 80401 USA. NR 25 TC 32 Z9 32 U1 0 U2 6 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-5021 J9 GRANUL MATTER JI Granul. Matter PD FEB PY 2003 VL 4 IS 4 BP 167 EP 174 DI 10.1007/s10035-002-0119-1 PG 8 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied SC Materials Science; Mechanics; Physics GA 652QQ UT WOS:000181390200004 ER PT J AU Korycansky, DG Zahnle, KJ AF Korycansky, DG Zahnle, KJ TI High-resolution simulations of the impacts of asteroids into the venusian atmosphere III: further 3D models SO ICARUS LA English DT Article DE impact processes ID COMET SHOEMAKER-LEVY-9; JUPITER; 253-MATHILDE; EXPLOSION AB We report on high-resolution three-dimensional calculations of oblique impacts into planetary atmospheres, specifically the atmosphere of Venus, extending the results of Korycansky et al. (2000, Icarus 146, 387-403; 2002, Icarus 157, 1-23). We have made calculations for impacts at 0degrees, 45degrees, and 60degrees from the vertical, different impactor velocities (10, 20, and 40 km s(-1)), and different impactor masses and orientations. We present results for porous impactors using a simple model of porosity. We have investigated the sensitivity to initial conditions of the calculations [as a follow-up to the results found in Korycansky et al. (2002)] and resolution effects. For use in cratering calculations, we fit simple functions to the numerical results for mass and momentum that penetrate to a given altitude (column mass) and investigate the behavior of the fit coefficients as functions of impactor parameters such as mass, velocity, and impact angle. Generally speaking, the mass and momentum (and hence resulting crater diameters) depend primarily on impactor mass and mass of atmosphere encountered and weakly or not at all on other parameters such as impactor velocity, impact angle, or porosity. The column mass to which the last portion of the impactor penetrates is approximately equal to the mass of impactor at the top of the atmosphere before the impact takes place. Finally, we present the beginnings of a simplified but physically based model for the impactor and its fragments to reproduce the mass and momentum fluxes as a function of height during the impact. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Korycansky, DG (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, CODEP, Santa Cruz, CA 95064 USA. NR 29 TC 8 Z9 8 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 2003 VL 161 IS 2 BP 244 EP 261 DI 10.1016/S0019-1035(02)00049-0 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500004 ER PT J AU Glenar, DA Samuelson, RE Pearl, JC Bjoraker, GL Blaney, D AF Glenar, DA Samuelson, RE Pearl, JC Bjoraker, GL Blaney, D TI Spectral imaging of martian water ice clouds and their diurnal behavior during the 1999 aphelion season (L-s=130 degrees) SO ICARUS LA English DT Article DE Mars; Mars atmosphere; infrared observations ID THERMAL EMISSION SPECTROMETER; HUBBLE-SPACE-TELESCOPE; GENERAL-CIRCULATION MODEL; OPTICAL-CONSTANTS; MU-M; MARS ATMOSPHERE; REFLECTANCE SPECTROSCOPY; H2O ICE; VIKING; TEMPERATURE AB We report high-spectral-resolution (lambda/deltalambda = 800-2300) near-infrared mapping observations of Mars at L-s = 130degrees (April 1999), which were obtained by drift-scanning the cryogenic long-slit spectrometer at the KPNO 2.2-m telescope across the disk. Data were reformatted into calibrated spectral image cubes (x,y,lambda) spanning 2.19 to 4.12 mum, which distinguish atmospheric CO2 features, solar lines, and surface and aerosol features. Maps of relative band depth between 3.0 and 3.5 mum trace water ice clouds and show the diurnal evolution of features in the persistent northern summer aphelion cloud belt, which was mapped contemporaneously but at fixed local time by the Mars Global Surveyor Thermal Emission Spectrometer (MGS/TES). Cloud optical depth, particle sizes, and ice aerosol content were estimated using a two-stream, single-layer scattering model, with Mie coefficients derived from recently published ice optical constants, followed by a linear spectral deconvolution process. A comparison of data and model spectra shows evaporating nighttime clouds in the morning followed by afternoon growth of a prominent orographic cloud feature on the west flank of Elysium Mons. Cloud optical depth at 3.2 mum evolved to 0.28 +/- 0.13 and ice aerosol column abundance to 0.9 +/- 0.3 pr mum in the afternoon. Column abundances as large as 0.17 pr mum were retrieved in nonorographic clouds within the aphelion cloud band around midday. These clouds exhibit a modest decline in optical depth during the afternoon. Results show that ice particle radii from <2 mum to >4 mum exist in both cloud types. However, large particles dominate the spectra, consistent with recent MGSfTES emission phase function measurements of aphelion cloud aerosol properties. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Glenar, DA (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. RI Bjoraker, Gordon/D-5032-2012 NR 66 TC 17 Z9 17 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 2003 VL 161 IS 2 BP 297 EP 318 DI 10.1016/S0019-1035(02)00046-5 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500007 ER PT J AU Banfield, D Conrath, BJ Smith, MD Christensen, PR Wilson, RJ AF Banfield, D Conrath, BJ Smith, MD Christensen, PR Wilson, RJ TI Forced waves in the martian atmosphere from MGS TES nadir data SO ICARUS LA English DT Article DE atmospheres; structure; Mars, atmosphere; meteorology; tides, atmospheric ID THERMAL EMISSION SPECTROMETER; GENERAL-CIRCULATION MODEL; STATIONARY WAVES; MARS; TIDES; TEMPERATURES; AEROBRAKING; DYNAMICS; MISSION AB We have analyzed the temperature retrievals from Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) nadir spectra to yield latitude-height resolved maps of various atmospheric forced wave modes as a function of season for a full Mars year. Among the isolated wave modes is the zonal mean, time mean temperature, which we used to derive zonal mean zonal winds and stationary wave quasi-geostrophic indices of refraction, diagnostic of their propagation. The diurnal Kelvin wave was isolated in the data, with results roughly consistent with models (Wilson and Hamilton, 1996, J. Atmos. Sci. 33, 1290-1326). The s = I and S = 2 stationary waves were found to have significant amplitude in ducts extending up the winter polar jets, while the s = 3 stationary wave was found to be confined to near the surface. The s = 1 stationary wave was found to have little phase tilt with height during northern winter, but significant westward phase tilt with height in the southern winter. This indicates that the wave carries heat poleward, slightly more than that found in Barnes et al. (1996; J. Geophys. Res. 101, 12,753-12,776). The s = I stationary wave is likely the dominant mechanism for eddy meridional heat transport for the southern winter. We noted that the phase of the s = 2 stationary wave is nearly constant with time, but that the s = 1 stationary wave moved 90degrees of longitude from fall to winter and back in spring in the North. While interannual variability is not yet addressed, overall, these results provide the first comprehensive benchmark for forced waves in Mars's atmosphere against which future atmospheric models of Mars can be compared. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Banfield, D (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RI Smith, Michael/C-8875-2012; OI Banfield, Don/0000-0003-2664-0164 NR 34 TC 69 Z9 69 U1 1 U2 4 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 2003 VL 161 IS 2 BP 319 EP 345 DI 10.1016/S0019-1035(02)00044-1 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500008 ER PT J AU Hudson, RS Ostro, SJ Scheeres, DJ AF Hudson, RS Ostro, SJ Scheeres, DJ TI High-resolution model of Asteroid 4179 Toutatis SO ICARUS LA English DT Article DE asteroids; radar; photometry; image processing ID RADAR; 4179-TOUTATIS; EROS AB A model of the shape of Toutatis based on "high-resolution" radar images obtained in 1992 and 1996 consists of 39,996 triangular facets of roughly equal area, defined by the locations of 20,000 vertices. These define the average spatial resolution of the model as approximately 34 m, significantly finer than Hudson and Ostro's (1995, Science 270, 84-86) model (1600 vertices, resolution 84 m). The high-resolution model reveals complex linear features as well as circular crater-like structures down to the resolution limit. There is a dichotomy between the gravitational slope distributions on the asteroid's two lobes. The noncraterlike features may be the manifestation of complex interior configurations involving monolithic fragments with various sizes and shapes, presumably due to collisions in various energy regimes. However, it may be impossible to decipher the interior structure and responsible collisional history of Toutatis and other small objects without extended, intensive, direct examination. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. Washington State Univ, Richland, WA 99352 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scheeres, DJ (reprint author), Univ Michigan, Dept Aerosp Engn, 3048 FXB, Ann Arbor, MI 48109 USA. NR 17 TC 28 Z9 33 U1 2 U2 6 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 2003 VL 161 IS 2 BP 346 EP 355 DI 10.1016/S0019-1035(02)00042-8 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500009 ER PT J AU Bakes, ELO Lebonnois, S Bauschlicher, CW McKay, CP AF Bakes, ELO Lebonnois, S Bauschlicher, CW McKay, CP TI The role of submicrometer aerosols and macromolecules in H-2 formation in the Titan haze SO ICARUS LA English DT Article DE Titan; stratospheric chemistry; hydrogen; aerosol charging ID POLYCYCLIC AROMATIC-HYDROCARBONS; ATMOSPHERE; HYDROGEN; CHEMISTRY; GRAINS; ATOM AB Previous studies of the photochemistry of small molecules in Titan's atmosphere found it difficult to have hydrogen atoms removed at a rate sufficient to explain the observed abundance of unsaturated hydrocarbons. One qualitative explanation of the discrepancy nominated catalytic aerosol surface chemistry as an efficient sink of hydrogen atoms, although no quantitative study of this mechanism was attempted. In this paper, we quantify how haze aerosols and macromolecules may efficiently catalyze the formation of hydrogen atoms into H-2 We describe the prompt reaction model for the formation of H-2 on aerosol surfaces and compare this with the catalytic formation of H-2 using negatively charged hydrogenated aromatic macromolecules. We conclude that the PRM is an efficient mechanism for the removal of hydrogen atoms from the atmosphere to form H-2 with a peak formation rate of similar to 70 cm(-3) s(-1) at 420 km. We also conclude that catalytic H-2 formation via hydrogenated anionic macromolecules is viable but much less productive (a maximum of similar to 0.1 cm(-3) s(-1) at 210 km) than microphysical aerosols. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Bakes, ELO (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 245-33, Moffett Field, CA 94035 USA. NR 27 TC 9 Z9 9 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 2003 VL 161 IS 2 BP 468 EP 473 DI 10.1016/S0019-1035(02)000404 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500016 ER PT J AU Lebonnois, S Bakes, ELO McKay, CP AF Lebonnois, S Bakes, ELO McKay, CP TI Atomic and molecular hydrogen budget in Titan's atmosphere SO ICARUS LA English DT Article DE Titan; photochemistry; atmospheres, composition ID METHANE; HAZE; NM AB Using a one-dimensional model, we investigate the hydrogen budget and escape to space in Titan's atmosphere. Our goal is to study in detail the distributions and fluxes of atomic and molecular hydrogen in the model, while identifying sources of qualitative and quantitative uncertainties. Our study confirms that the escape of atomic and molecular hydrogen to space is limited by the diffusion through the homopause level. The H distribution and flux inside the atmosphere are very sensitive to the eddy diffusion coefficient used above altitude 600 km. We chose a high value of this coefficient 1 x 10(8) cm(2) s(-1) and a homopause level around altitude 900 km. We find that H flows down significantly from the production region above 500 km to the region [300-500] km, where it recombines into H-2. Production of both H and H2 also occurs in the stratosphere, mostly from photodissociation of acetylene. The only available observational data to be compared are the escape rate of H deduced from Pioneer 11 and IUE observations of the H torus 1-3 x 10(9) cm(-2) s(-1) and the latest retrieved value of the H-2 mole fraction in the stratosphere: (1.1 +/- 0.1) x 10(-3). Our results for both of these values are at least 50-100% higher, though the uncertainties within the chemical schemes and other aspects of the model are large. The chemical conversion from H to H, is essentially done through catalytic cycles using acetylene and diacetylene. We have studied the role of this diacetylene cycle, for which the associated reaction rates are poorly known. We find that it mostly affects C, species and benzene in the lower atmosphere, rather than the H profile and the hydrogen budget. We have introduced the heterogenous recombination of hydrogen on the surface of aerosol particles in the stratosphere, and this appears to be a significant process, comparable to the chemical processes. It has a major influence on the H distribution, and consequently on several other species, especially C3H4, C4H2 and C6H6. Therefore, this heterogenous process should be taken into account when trying to understand the stratospheric distribution of these hydrocarbons. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Univ Paris 06, Meteorol Dynam Lab, F-75252 Paris 05, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lebonnois, S (reprint author), Univ Paris 06, Meteorol Dynam Lab, Box 99, F-75252 Paris 05, France. OI LEBONNOIS, SEBASTIEN/0000-0002-2390-8164 NR 26 TC 36 Z9 36 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 2003 VL 161 IS 2 BP 474 EP 485 DI 10.1016/S0019-1035(02)00039-8 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500017 ER PT J AU Moore, MH Hudson, RL AF Moore, MH Hudson, RL TI Infrared study of ion-irradiated N-2-dominated ices relevant to Triton and Pluto: formation of HCN and HNC SO ICARUS LA English DT Article DE radiation chemistry; Pluto; Triton; spectroscopy; ices ID DENSE MOLECULAR CLOUDS; TIME-DEPENDENT CHEMISTRY; OUTER SOLAR-SYSTEM; COMET HALE-BOPP; INTERSTELLAR ICES; HYDROGEN-CYANIDE; FROZEN METHANE; UV PHOTOLYSIS; GRAIN MANTLES; SOLID NEON AB Infrared spectra and radiation chemical behavior of N-2-dominated ices relevant to the surfaces of Triton and Pluto are presented. This is the first systematic IR study of proton-irradiated N-2-rich ices containing CH, and CO. Experiments at 12 K show that HCN, HNC, and diazomethane (CH2N2) form in the solid phase, along with several radicals. NH3 is also identified in irradiated N-2 + CH4 and N-2 + CH4 + CO. We show that HCN and HNC are made in irradiated binary ice mixtures having initial N-2/CH4 ratios from 100 to 4, and in three-component mixtures have an initial N-2/(CH4 + CO) ratio of 50. HCN and HNC are not detected in N-2-dominated ices when CH4 is replaced with C2H6, C2H2, or CH3OH. The intrinsic band strengths of HCN and HNC are measured and used to calculate G(HCN) and G(HNC) in irradiated N-2 + CH4 and N-2 + CH4 + CO ices. In addition, the HNC/HCN ratio is calculated to be similar to 1 in both icy mixtures. These radiolysis results reveal, for the first time, solid-phase synthesis of both HCN and HNC in N2-rich ices containing CH4. We examine the evolution of spectral features due to acid-base reactions (acids such as HCN, HNC, and HNCO and a base, NH3) triggered by warming irradiated ices from 12 K to 30-35 K. We identify anions (OCN-, CN-, and N-3(-)) in ices warmed to 35 K. These ions are expected to form and survive on the surfaces of Triton and Pluto. Our results have astrobiological implications since many of these products (HCN, HNC, HNCO, NH3, NH4OCN, and NH4CN) are involved in the syntheses of biomolecules such as amino acids and polypeptides. (C) 2003 Elsevier Science (USA). All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Eckerd Coll, Dept Chem, St Petersburg, FL 33733 USA. RP Moore, MH (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Hudson, Reggie/E-2335-2012 NR 86 TC 92 Z9 92 U1 1 U2 21 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 2003 VL 161 IS 2 BP 486 EP 500 DI 10.1016/S0019-1035(02)00037-4 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 653FA UT WOS:000181423500018 ER PT J AU Krol, SJ Rao, GM AF Krol, SJ Rao, GM TI Hubble performance on-orbit SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB A summary of the Hubble Space Telescope (HST) nickel-hydrogen (NiH,) battery performance from launch to the present. Over the life of HST vehicle configuration, charge system degradation and failures, together with thermal design limitations, have had a significant effect on the capacity of HST batteries. Changes made to the charge system configuration to. protect against power system failures and to maintain battery thermal stability resulted in undercharging of the batteries. This undercharging resulted in decreased usable battery capacity as well as battery cell voltage/capacity divergence. This cell divergence was made. evident during on-orbit battery capacity measurements by a relatively shallow slope of the discharge curve following the discharge knee. Early efforts to improve battery performance have been successful. On-orbit capacity measurement data indicates increases in the usable battery capacity of all six batteries as well as improvements in the battery cell voltage/capacity divergence. Additional measures have been implemented to improve battery performance, however, failures within the HST Power Control Unit (PCU) have prevented verification of battery status. As this PCU fault prevents the execution of on-orbit capacity testing, the HST Project has based battery capacity on trends which utilizes previous on-orbit battery capacity test data, for science mission and servicing mission planning. The Servicing Mission 3B (SM-3B) in March 2002 replaced the faulty PCU. Following the servicing mission, on-orbit capacity testing resumed; battery performance since launch is reviewed. C1 Lockheed Martin Tech Operat, Elect Power Subsyst, Hubble Space Telescope, Greenbelt, MD 20770 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krol, SJ (reprint author), Lockheed Martin Tech Operat, Elect Power Subsyst, Hubble Space Telescope, 474 Greenway Ctr Dr,Suite 200, Greenbelt, MD 20770 USA. NR 2 TC 0 Z9 0 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD FEB PY 2003 VL 18 IS 2 BP 13 EP 17 DI 10.1109/MAES.2003.1183863 PG 5 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 644EX UT WOS:000180905900003 ER PT J AU Morabito, DD Shambayati, S Finley, S Fort, D AF Morabito, DD Shambayati, S Finley, S Fort, D TI The Cassini May 2000 solar conjunction SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE charged particles; propagation; scattering; scintillation; solar plasma ID DENSITY FLUCTUATIONS; SCINTILLATION; WIND AB Interplanetary spacecraft, which fly in the ecliptic plane, typically encounter solar conjunctions during their main missions. The communications link between an interplanetary spacecraft and Earth is affected by the charged particles that constitute the intervening solar corona and solar wind. As the Sun-Earth-probe (SEP) angle becomes small (usually <3degrees for X band or 8.43 GHz), the signal suffers increased degradation. The effects on the received signal include time delay and phase fluctuations due to the fluctuating columnar electron density, which in turn cause carrier lock problems and telemetry data loss. Because of these effects, studies of solar corona charged particle effects on spacecraft signals were conducted to determine strategies for optimizing data return during these periods. The first solar conjunction of the Cassini spacecraft occurred between May 8, 2000 (2000/129) and May 18, 2000 (2000/139). During this period, the Cassini spacecraft was within 3.2degrees of the Sun as seen from Earth with the minimum SEP angle of 0.56degrees occurring on May 13 (2000/134). This solar conjunction occurred prior to the expected peak of the current solar cycle. Coherent dual-frequency X band (8.43 GHz) and Ka band (32 GHz) data were acquired from 3.2degrees to near the minimum SEP angle at 0.6degrees for both ingress and egress. The measurements of amplitude scintillation, spectral broadening and phase scintillation were examined as a function of SEP angle. As expected, these solar effects are significantly less at Ka band than at X band for the same SEP angle. This study's results will be combined with those of other spacecraft solar conjunctions in order to build a statistical database of solar effects as a function of solar elongation angle and phase of the solar cycle. Such studies are useful in the design of telecommunications systems for future spacecraft missions, which may have stringent communication requirements during their solar conjunction phases. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Morabito, DD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 18 TC 14 Z9 18 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD FEB PY 2003 VL 51 IS 2 BP 201 EP 219 DI 10.1109/TAP.2003.809055 PG 19 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 672LL UT WOS:000182522000006 ER PT J AU Parkinson, CL Chahine, MT Kummerow, CD Salomonson, VV AF Parkinson, CL Chahine, MT Kummerow, CD Salomonson, VV TI Foreword to the EOS Aqua special issue SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Parkinson, CL (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Parkinson, Claire/E-1747-2012 OI Parkinson, Claire/0000-0001-6730-4197 NR 0 TC 4 Z9 5 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 172 EP 172 DI 10.1109/TGRS.2003.811217 PG 1 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600001 ER PT J AU Parkinson, CL AF Parkinson, CL TI Aqua: An earth-observing satellite mission to examine water and other climate variables SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Aqua; Earth Observing System (EOS); remote sensing; satellites; water cycle ID IMAGING SPECTRORADIOMETER MODIS; RADIATION BUDGET EXPERIMENT; ENERGY SYSTEM CERES; SOIL-MOISTURE; RETRIEVAL; ALGORITHM; SCIENCE; CLOUDS; IRIS AB Aqua is a major satellite mission of the Earth Observing System (EOS), an international program centered at the U.S. National Aeronautics and Space Administration (NASA). The Aqua satellite carries six distinct earth-observing instruments to measure numerous aspects of earth's atmosphere, land, oceans, biosphere, and cryosphere, with a concentration on water in the earth system. Launched on May 4, 2002, the satellite is in a sun-synchronous orbit at an altitude of 705 km, with a track that takes it north across the equator at 1:30 P.M. and south across the equator at 1:30 A.M. All of its earth-observing instruments are operating, and all have the ability to obtain global measurements within two days. The Aqua data will be archived and available to the research community through four Distributed Active Archive Centers (DAACs). C1 NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Parkinson, CL (reprint author), NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Code 971, Greenbelt, MD 20771 USA. RI Parkinson, Claire/E-1747-2012 OI Parkinson, Claire/0000-0001-6730-4197 NR 59 TC 190 Z9 206 U1 3 U2 23 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 173 EP 183 DI 10.1109/TGRS.2002.808319 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600002 ER PT J AU Njoku, EG Jackson, TJ Lakshmi, V Chan, TK Nghiem, SV AF Njoku, EG Jackson, TJ Lakshmi, V Chan, TK Nghiem, SV TI Soil moisture retrieval from AMSR-E SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE hydrology; microwave; radiometry; remote sensing; satellite; soil moisture ID PASSIVE MICROWAVE MEASUREMENTS; BRIGHTNESS TEMPERATURES; UNITED-STATES; WATER-CONTENT; VEGETATION; EMISSION; MODEL; INDEX; HETEROGENEITY; POLARIZATION AB The Advanced Microwave Scanning Radiometer (AMSR-E) on the Earth Observing System (EOS) Aqua satellite was launched on May 4, 2002. The AMSR-E instrument provides a potentially improved soil moisture sensing capability over previous spaceborne radiometers such as the Scanning Multichannel Microwave Radiometer and Special Sensor Microwave/Imager due to its combination of low frequency and higher spatial resolution (approximately 60 km at 6.9 GHz). The AMSR-E soil moisture retrieval approach and its implementation are described in this paper. A postlaunch validation program is in progress that will provide evaluations of the retrieved soil moisture and enable improved hydrologic applications of the data. Key aspects of the validation program include assessments of the effects on retrieved soil moisture of variability in vegetation water content, surface temperature, and spatial heterogeneity. Examples of AMSR-E brightness temperature observations over land are shown from the first few months of instrument operation, indicating general features of global vegetation and soil moisture variability. The AMSR-E sensor calibration and extent of radio frequency interference are currently being assessed, to be followed by quantitative assessments of the soil moisture retrievals. The AMSR-E instrument was developed by the National Space Development Agency of Japan (NASDA) and provided to the U.S. National Aeronautics. and Space Administration. A similar instrument was launched in December 2002 on NASDA's ADEOS-II satellite. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. USDA ARS, Beltsville Agr Res Ctr, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. Univ S Carolina, Dept Geol Sci, Columbia, SC 29208 USA. RP Njoku, EG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Xie, Xingmei/G-7311-2011; Lakshmi, Venkat/I-3078-2016 OI Lakshmi, Venkat/0000-0001-7431-9004 NR 52 TC 684 Z9 740 U1 13 U2 118 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 215 EP 229 DI 10.1109/TGRS.2002.808243 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600006 ER PT J AU Kelly, RE Chang, AT Tsang, L Foster, JL AF Kelly, RE Chang, AT Tsang, L Foster, JL TI A prototype AMSR-E global snow area and snow depth algorithm SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE dense media radiative transfer model; microwave radiometry; remote sensing; snow depth ID WATER EQUIVALENT; SSM/I MEASUREMENTS; MICROWAVE; VARIABILITY; RETRIEVAL; EXTENT; SPACE AB dA methodologically simple approach to estimate snow depth from spaceborne microwave instruments is described. The scattering signal observed in multifrequency passive microwave data is used to detect snow cover. Wet snow, frozen ground, precipitation, and other anomalous scattering signals are screened using established methods. The results from two different approaches (a simple time and continentwide static approach and a space and time dynamic approach) to estimating snow depth were compared. The static approach, based on radiative transfer calculations, assumes a temporally constant grain size and density. The dynamic approach assumes that snowpack properties are spatially and temporally dynamic and requires two simple empirical models of density and snowpack grain radius evolution, plus a dense media radiative transfer model based on the quasicrystalline approximation and sticky particle theory. To test the approaches, a four-year record of daily snow depth measurements at 71 meteorological stations plus passive microwave data from the Special Sensor Microwave Imager, land cover data and a digital elevation model were used. In addition, testing was performed for a global dataset of over 1000 World Meteorological Organization meteorological stations recording snow depth during the 2000-2001 winter season. When compared with the snow depth data, the new algorithm had an average error of 23 cm for the one-year dataset and 21 cm for the four-year dataset (131% and 94% relative error, respectively). More importantly, the dynamic algorithm tended to underestimate the snow depth less than the static algorithm. This approach will be developed further and implemented for use with the Advanced Microwave Scanning Radiometer-Earth Observing System aboard Aqua. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. RP Kelly, RE (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NR 40 TC 231 Z9 254 U1 3 U2 47 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 230 EP 242 DI 10.1109/TGRS.2003.809118 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600007 ER PT J AU Comiso, JC Cavalieri, DJ Markus, T AF Comiso, JC Cavalieri, DJ Markus, T TI Sea ice concentration, ice temperature, and snow depth using AMSR-E data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE algorithms; Arctic regions; microwave radiometry; sea ice; snow; temperature ID INTERANNUAL VARIABILITY; COASTAL POLYNYAS; WEDDELL SEA; SOUTHERN-OCEAN; ARCTIC-OCEAN; MODEL; CONVECTION; HALOCLINE; TRENDS AB A summary of the theoretical basis and initial performance of the algorithms that are used to derive sea ice concentration, ice temperature, and snow depth on sea ice from newly acquired Earth Observing System-Aqua/Advanced Microwave Scanning Radiometer-EOS (AMSR-E) radiances is presented. The algorithms have been developed and tested using historical satellite passive microwave data and are expected to provide more accurate products, since they are designed to take advantage of the wider range of frequencies and higher spatial resolution of the AMSR-E microwave instrument. Validation programs involving coordinated satellite, aircraft, and surface measurements to determine the accuracies of these sea ice products and to improve further our capability to monitor global sea ice are currently underway. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Markus, Thorsten/D-5365-2012 NR 47 TC 119 Z9 124 U1 3 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 243 EP 252 DI 10.1109/TGRS.2002.808317 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600008 ER PT J AU Aumann, HH Chahine, MT Gautier, C Goldberg, MD Kalnay, E McMillin, LM Revercomb, H Rosenkranz, PW Smith, WL Staelin, DH Strow, LL Susskind, J AF Aumann, HH Chahine, MT Gautier, C Goldberg, MD Kalnay, E McMillin, LM Revercomb, H Rosenkranz, PW Smith, WL Staelin, DH Strow, LL Susskind, J TI AIRS/AMSU/HSB on the aqua mission: Design, science objectives, data products, and processing systems SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE climate; greenhouse gases; humidity sounder; hyperspectral; infrared; microwave; temperature sounder; weather forecasting ID SATELLITE AB The Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU), and the Humidity Sounder for Brazil (HSB) form an integrated cross-track scanning temperature and humidity sounding system on the Aqua satellite of the Earth Observing System (EOS). AIRS is an infrared spectrometer/radiometer that covers the 3.7-15.4-tim spectral range with 2378 spectral channels. AMSU is a 15-channel microwave radiometer operating between 23 and 89 GHz. HSB is a four-channel microwave radiometer that makes measurements between 150 and 190 GHz. In addition to supporting the National Aeronautics and Space Administration's interest in process study and climate research, AIRS is the first hyperspectral infrared radiometer designed to support the operational requirements for medium-range weather forecasting of the National Ocean and Atmospheric Administration's National Centers for Environmental Prediction (NCEP) and other numerical weather forecasting centers. AIRS, together with the AMSU and HSB microwave radiometers, will achieve global retrieval accuracy of better than 1 K in the lower troposphere under clear and partly cloudy conditions. This paper presents an overview of the science objectives, AIRS/AMSU/HSB data products, retrieval algorithms, and the ground-data processing concepts. The EOS Aqua was launched on May 4, 2002 from Vandenberg AFB, CA, into a 705-km-high, sun-synchronous orbit. Based on the excellent radiometric and spectral performance demonstrated by AIRS during prelaunch testing, which has by now been verified during on-orbit testing, we expect the assimilation of AIRS data into the numerical weather forecast to result in significant forecast range and reliability improvements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Camp Springs, MD 20746 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. MIT, Cambridge, MA 02139 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Aumann, HH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kalnay, Eugenia/F-4393-2010; Goldberg, Mitch/F-5589-2010; OI Kalnay, Eugenia/0000-0002-9984-9906 NR 40 TC 696 Z9 732 U1 13 U2 60 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 253 EP 264 DI 10.1109/TGRS.2002.808356 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 671ZB UT WOS:000182494600009 ER PT J AU Pagano, TS Aumann, HH Hagan, DE Overoye, K AF Pagano, TS Aumann, HH Hagan, DE Overoye, K TI Prelaunch and in-flight radiometric calibration of the Atmospheric Infrared Sounder (AIRS) SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; infrared radiometry; infrared spectroscopy; remote sensing AB With 2378 infrared spectral channels ranging in wavelength from 3.7-15.4mum, the Atmospheric Infrared Sounder (AIRS) represents a quantum leap in spaceborne sounding instruments. Each channel of the AIRS instrument has a well-defined spectral bandshape and must be radiometrically calibrated to standards developed by the National Institute of Standards and Technology. This paper defines the algorithms, methods, and test results of the prelaunch radiometric calibration of the AIRS infrared channels and the in-flight calibration approach. Derivation of the radiometric transfer equations is presented with prelaunch measurements of the radiometric accuracy achieved on measurements of independent datasets. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. BAE Syst, Lexington, MA 02421 USA. RP Pagano, TS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 119 Z9 121 U1 3 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 265 EP 273 DI 10.1109/TGRS.2002.808324 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600010 ER PT J AU Strow, LL Hannon, SE Weiler, M Overoye, K Gaiser, SL Aumann, HH AF Strow, LL Hannon, SE Weiler, M Overoye, K Gaiser, SL Aumann, HH TI Prelaunch spectral calibration of the Atmospheric Infrared Sounder (AIRS) SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric retrievals; calibration; grating spectrometer; remote sensing AB The Atmospheric Infrared Sounder (AIRS) is a high-resolution infrared sounder launched aboard the National Aeronautics and Space Administration's Aqua satellite on May 4, 2002. AIRS is a grating spectrometer with 2378 channels located between 15 and 3.8 mum, with nominal resolving powers of nu/Deltanu = 1200. As the first of a new generation of upcoming infrared instruments with similar spectral coverage and resolution, there will be much interest in the performance of AIRS. The ability to retrieve good atmospheric profiles from AIRS observations will depend in part upon our knowledge of the spectral response of AIRS to the upwelling radiance. This paper discusses the spectral calibration of AIRS based upon an extensive set of laboratory test data generated by the instruments prime contractor, BAE. In particular, we describe the calibration of the AIRS spectral response functions, showing that our requirement for accuracies of "1% of a width" have been achieved. C1 Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. BAE Syst, Lexington, MA 02421 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Strow, LL (reprint author), Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA. NR 7 TC 32 Z9 33 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 274 EP 286 DI 10.1109/TGRS.2002.808245 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600011 ER PT J AU Gaiser, SL Aumann, HH Strow, LL Hannon, SE Weiler, M AF Gaiser, SL Aumann, HH Strow, LL Hannon, SE Weiler, M TI In-flight spectral calibration of the atmospheric infrared sounder SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmosphere; grating spectrometer; spectral calibration ID SPACED DATA AB Preflight testing of AIRS determined that the shapes of the detector spectral response functions (SRFs) do not vary under different instrument conditions. This reduces in-flight spectral calibration to the determination of detector spectral centroids. A spectrometer grating model has been developed to calculate detector centroids. Only two parameters of this model need to be determined in orbit. An algorithm is presented for determining these two parameters in orbit by correlating observed upwelling radiance spectra with modeled spectra. The method of selecting spectral regions against which to correlate is detailed. The in-orbit spectral calibration algorithm was tested on one day of simulated global AIRS radiances, showing that the uncertainty in the frequencies of the SRF centroids is between 0.006 Deltanu and 0.01 Deltanu, compared to the spectral calibration requirement of 0.01 Deltanu, where Deltanu is the SRF full width at half maximum. The simulation also indicates that the stability of the spectral calibration can be monitored at the 0.001-Deltanu level on a daily basis. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21205 USA. BAE Syst, Elect Warfare Div, Lexington, MA 02421 USA. RP Gaiser, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 22 Z9 23 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 287 EP 297 DI 10.1109/TGRS.2003.809708 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600012 ER PT J AU Gregorich, DT Aumann, HH AF Gregorich, DT Aumann, HH TI Verification of AIRS boresight accuracy using coastline detection SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE AIRS; calibration; coastlines; geolocation AB The longitude and latitude of the centroids of the Atmospheric Infrared Sounder (AIRS) infrared spectrometer footprints are calculated by the Level la calibration software based on transformations of scan angles, instrument alignment angles relative to the Earth Observing System Aqua spacecraft, and the spacecraft ephemeris. The detection of coastline crossings is used to determine the accuracy of these coordinates. Tests using simulated AIRS data derived from real Moderate Resolution Imaging Spectroradiometer (MODIS) Terra satellite 10-mum window data indicate that an accuracy of 1.7 km is easily achievable with modest amounts of data, such as should be available from AIRS by launch + 90 days. This accuracy is a small fraction of the 13.5-km AIRS footprint and is consistent with the accuracy required by the Level 2 software. Preliminary results from actual AIRS data indicate that the algorithm works as predicted. For combined use of the AIRS 13.5-km footprints with MODIS 1-km footprints, accuracy of the order of 0.5 km is desirable. This accuracy may be achievable with several months of data, but depends on the accuracy of the reference map and whether a sufficient number of large clear homogeneous surface scenes can be found. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Calif State Univ Los Angeles, Dept Phys & Astron, Los Angeles, CA 90032 USA. RP Gregorich, DT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 12 Z9 13 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 298 EP 302 DI 10.1109/TGRS.2002.808311 PG 5 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600013 ER PT J AU Fishbein, E Farmer, CB Granger, SL Gregorich, DT Gunson, MR Hannon, SE Hofstadter, MD Lee, SY Leroy, SS Strow, LL AF Fishbein, E Farmer, CB Granger, SL Gregorich, DT Gunson, MR Hannon, SE Hofstadter, MD Lee, SY Leroy, SS Strow, LL TI Formulation and validation of simulated data for the Atmospheric Infrared Sounder (AIRS) SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE algorithm development; atmospheric retrieval; cloud scene modeling; data simulation; High Resolution Infrared Sounder (HIRS); satellite remote sensing ID SEA-SURFACE; LAND-COVER; EMISSIVITY; VERIFICATION; TEMPERATURE; SYSTEM; LAYER; MODEL; AMSU AB Models for synthesizing radiance measurements by the Atmospheric Infrared Sounder (AIRS) are described. Synthetic radiances have been generated for developing and testing data processing algorithms. The radiances are calculated from geophysical states derived from weather forecasts and climatology using the AIRS rapid transmission algorithm. The data contain horizontal variability at the spatial resolution of AIRS from the surface and cloud fields. This is needed to test retrieval algorithms under partially cloudy conditions. The surface variability is added using vegetation and International Geosphere Biosphere Programme surface type maps, while cloud variability is added randomly. The radiances are spectrally averaged to create High Resolution Infrared Sounder (HIRS) data, and this is compared with actual HIRS2 data on the NOAA 14 satellite. The simulated data underrepresent high-altitude equatorial cirrus clouds and have too much local variability. They agree in the mean to within 1-4 K, and global standard deviation agrees to better than 2 K. Simulated data have been a valuable tool for developing retrieval algorithms and studying error characteristics and will continue to be so after launch. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21205 USA. RP Fishbein, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 44 TC 21 Z9 21 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 314 EP 329 DI 10.1109/TGRS.2002.808325 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600015 ER PT J AU Gautier, C Shiren, Y Hofstadter, M AF Gautier, C Shiren, Y Hofstadter, M TI AIRS/Vis near IR instrument SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; cloud detection; cloud height; surface irradiance; surface solar radiation; three-dimensional (3-D) cloud effects; visible; near Infra-Red ID SURFACE SOLAR IRRADIANCE; RADIATIVE-TRANSFER MODEL; RADIOMETRIC CALIBRATION; SATELLITE DATA; SCATTERING; REFLECTANCE; ATMOSPHERE; CHANNELS; PROJECT; NOAA-7 AB A component of the Atmospheric Infrared Sounder (AIRS) instrument system is the AIRS/Visible Near InfraRed (Vis/NIR) instrument. With a nadir ground resolution of 2.28 km and four channels, the Vis/NIR instrument provides diagnostic support to the infrared retrievals from the AIRS instrument and several research products, including surface solar flux studies. The AIRS Vis/NIR is composed of three narrowband (channel 1: 0.4070.44 mum; channel 2: 0.58-0.68 mum, and channel 3: 0.71-0.92 mum) and one broadband (channel 4: 0.49-0.94 mum) channel, each a linear detector array of nine pixels. It is calibrated onboard with three tungsten lamps. Vicarious calibrations using ground targets of known reflectance and a cross-calibration with the Moderate Resolution Imaging Spectroradiometer (MODIS) augment the onboard calibration. One of AIRS Vis/NIR's principal supporting functions is the detection of low clouds to flag these conditions for atmospheric temperature retrievals. Once clouds are detected, a cloud height index is obtained based on the ratio (channel 2 - channel 3)/channel 1 that is sensitive to the partitioning of water vapor absorption above and below clouds. The determination of the surface solar radiation flux is principally based on channel 4 broadband measurements and the well-established relationship between top-of-the atmosphere (broadband) radiance and the surface irradiance. C1 Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gautier, C (reprint author), Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. NR 35 TC 22 Z9 23 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 330 EP 342 DI 10.1109/TGRS.2002.808242 PG 13 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600016 ER PT J AU Lambrigtsen, BH Lee, SY AF Lambrigtsen, BH Lee, SY TI Coalignment and synchronization of the AIRS instrument suite SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric measurements; calibration; radiometry; remote sensing AB Previous multispectral sounders have consisted of infrared and microwave instruments operated asynchronously, with the data interpolated during ground processing to common fields of view (FOVs) for geophysical retrieval processing. To help achieve the high retrieval accuracy required for the Atmospheric Infrared Sounder (AIRS) system, the four instruments making up the AIRS suite are aligned and synchronized in such a way as to achieve common FOVs without,interpolation. We describe the system, how the alignment is accomplished, and the plans to verify performance after launch and compensate for misalignments that might be revealed then. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91009 USA. RP Lambrigtsen, BH (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91009 USA. NR 2 TC 18 Z9 19 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 343 EP 351 DI 10.1109/TGRS.2002.80846 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600017 ER PT J AU Lambrigtsen, BH Calheiros, RV AF Lambrigtsen, BH Calheiros, RV TI The humidity sounder for Brazil - An international partnership SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric measurements; humidity measurement; microwave radiometry; remote sensing AB The Humidity Sounder for Brazil (HSB) is a crucial component of the Atmospheric Infrared Sounder (AIRS) sounding suite and a valuable contribution from Brazil to the National Aeronautics and Space Administration's Aqua mission. Its design and functionality are practically identical to that of the Advanced Microwave Sounding Unit-B-proven on the latest National Oceanic and Atmospheric Administration's, weather satellites. We briefly discuss,its heritage, the measurement concept and principle of operation, and the design. The complex multinational acquisition process employed for HSB is described, along with the approach to be used for operations, derivation of radiometric and geophysical data products, and validation of those products-with emphasis on activities in Brazil. We also describe postlaunch research plans and discuss the importance of humidity observations in tropical regions like Brazil. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91009 USA. Brazilian Space Agcy, Brazilian Natl Inst Space Res, Sao Paulo, Brazil. Univ State Sao Paulo, Meteorol Res Inst, Sao Paulo, Brazil. RP Lambrigtsen, BH (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91009 USA. NR 12 TC 20 Z9 21 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 352 EP 361 DI 10.1109/TGRS.2002.808304 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600018 ER PT J AU Lambrigtsen, BH AF Lambrigtsen, BH TI Calibration of the AIRS microwave instruments SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospberic measurements; calibration; microwave radiometry; remote sensing AB Aqua carries three microwave radiometers that form an integral part of the Atmospheric Infrared Souding (AIRS) sounding suite. Two Advanced Microwave Sounding. Unit-A modules, one operating with two channels in the 23-31-GHz range and on e operating with 12-channels in the 50-60-GHz range and one channel at 89 GHz, provide all-weather temperature soundings and cloud information. The Humidity Sounder for Brazil operates with four channels-in the 150-190-GHz range and provides all-weather humidity and cloud soundings. All are crosstrack scanners, as is AIRS. While there are significant differences between these three instruments, they are sufficiently alike that a common approach can be used to calibrate them. We describe the instruments and their heritage, the onboard calibration system, and the ground-based calibration processing. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91009 USA. RP Lambrigtsen, BH (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, 4800 Oak Grove Dr, Pasadena, CA 91009 USA. NR 5 TC 43 Z9 44 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 369 EP 378 DI 10.1109/TGRS.2002.808247 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600020 ER PT J AU Susskind, J Barnet, CD Blaisdell, JM AF Susskind, J Barnet, CD Blaisdell, JM TI Retrieval of atmospheric and surface parameters from AIRS/AMSU/HSB data in the presence of clouds SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE infrared measurements; inverse problems; iterative methods; linear approximation; matrices; microwave measurements; moisture measurements; remote sensing; satellites; temperature measurement ID INVERSION; RADIANCES; RADIATION; SOUNDER AB New state-of-the-art methodology is described to analyze the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit/Humidity Sounder for Brazil (AIRS/AMSU/HSB) data in the presence of multiple cloud formations. The methodology forms the basis for, the AIRS Science Team algorithm, which will be used to analyze AIRS/AMSU/HSB data on the Earth Observing System Aqua platform. The cloud-clearing methodology requires no knowledge of. the spectral properties of the clouds. The basic retrieval methodology is general and extracts the maximum information from the radiances, consistent with the channel noise covariance matrix. The retrieval methodology minimizes the dependence of the solution on the first-guess field and the first-guess error characteristics. Results are shown for AIRS Science Team simulation studies with multiple cloud formations. These simulation studies imply that clear column radiances can,be reconstructed under partial cloud cover with an accuracy comparable to single spot channel noise in the temperature and water vapor sounding regions; temperature soundings can be produced under partial cloud cover with RMS errors on the order of, or better than, 1 degreesK in 1-km-thick layers from the surface to 700 mb, 1-km layers from 700-300 mb, 3-km layers from 300-30 mb, and 5-km layers from 30-1 mb; and moisture profiles can be obtained with an accuracy better than 20% absolute errors in 1-km layers from the surface to nearly 200 mb. C1 NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst Technol, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, Greenbelt, MD 20771 USA. RP Susskind, J (reprint author), NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst Technol, Code 661, Greenbelt, MD 20771 USA. RI Barnet, Christopher/F-5573-2010 NR 25 TC 393 Z9 411 U1 4 U2 31 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 390 EP 409 DI 10.1109/TGRS.2002.808236 PG 20 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600022 ER PT J AU Fetzer, E McMillin, LM Tobin, D Aumann, HH Gunson, MR McMillan, WW Hagan, DE Hofstadter, MD Yoe, J Whiteman, DN Barnes, JE Bennartz, R Vomel, H Walden, V Newchurch, M Minnett, PJ Atlas, R Schmidlin, F Olsen, ET Goldberg, MD Zhou, SS Ding, HJ Smith, WL Revercomb, H AF Fetzer, E McMillin, LM Tobin, D Aumann, HH Gunson, MR McMillan, WW Hagan, DE Hofstadter, MD Yoe, J Whiteman, DN Barnes, JE Bennartz, R Vomel, H Walden, V Newchurch, M Minnett, PJ Atlas, R Schmidlin, F Olsen, ET Goldberg, MD Zhou, SS Ding, HJ Smith, WL Revercomb, H TI AIRS/AMSU/HSB validation SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric measurements; infrared spectroscopy; inverse problems; microwave radiometry; remote sensing; terrestrial atmosphere ID SEA-SURFACE TEMPERATURE; EMITTED RADIANCE INTERFEROMETER; COMPLEX QUALITY-CONTROL; WATER-VAPOR; ENVIRONMENTAL PREDICTION; RADIOSONDE HEIGHTS; NATIONAL CENTERS; RAMAN LIDAR; SATELLITE; CLOUD AB The Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit/Humidity Sounder for Brazil (AIRS/AMSU/HSB) instrument suite onboard Aqua observes infrared and microwave radiances twice daily over most of the planet. AIRS offers unprecedented radiometric accuracy and signal to noise throughout the thermal infrared. Observations from the combined suite of AIRS, AMSU, and HSB are processed into retrievals of atmospheric parameters such as temperature, water vapor, and trace gases under all but the cloudiest conditions. A more limited retrieval set based on the microwave radiances is obtained under heavy cloud cover. Before measurements and retrievals from AIRS/AMSU/HSB instruments can be fully utilized they must be compared with the best possible in situ and other ancillary "truth" observations. Validation is the process of estimating the measurement and retrieval uncertainties through comparison with a set of correlative data of known uncertainties. The ultimate goal of the validation effort is retrieved product uncertainties constrained to those of radiosondes; tropospheric rms uncertainties of 1.0 degreesC over a 1-km layer for temperature, and 10% over 2-km layers for water vapor. This paper describes the data sources and approaches to be used for validation of the AIRS/AMSU/HSB instrument suite, including validation of the forward models necessary for calculating observed radiances, validation of the observed radiances themselves, and validation of products retrieved from the observed radiances. Constraint of the AIRS product uncertainties to within the claimed specification of 1 K/1 kin over well-instrumented regions is feasible within 12 months of launch, but global validation of all AIRS/AMSU/HSB products may require considerably more time due to the novelty and complexity of this dataset and the sparsity of some types of correlative observations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Camp Springs, MD 20746 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. Univ Kansas, Lawrence, KS 66045 USA. Natl Ocean & Atmospher, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. Univ Idaho, Moscow, ID 83844 USA. Univ Alabama, Huntsville, AL 35899 USA. Univ Miami, Coral Gables, FL 33124 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fetzer, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Atlas, Robert/A-5963-2011; Goldberg, Mitch/F-5589-2010; Bennartz, Ralf/F-3760-2010 OI Atlas, Robert/0000-0002-0706-3560; NR 55 TC 77 Z9 80 U1 1 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 418 EP 431 DI 10.1109/TGRS.2002.808293 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600024 ER PT J AU Hagan, DE Minnett, PJ AF Hagan, DE Minnett, PJ TI AIRS radiance validation over ocean from sea surface temperature measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE drifting buoy; infrared radiometry; remote sensing; satellite radiometry; sea surface temperature ID SATELLITE MEASUREMENTS; RADIOMETER; ACCURACY AB This paper demonstrates the accuracy of methods and in situ data for early validation of calibrated earth scene radiances measured by the Atmospheric InfraRed Sounder (AIRS) on the Aqua spacecraft. We describe an approach for validation that relies on comparisons of AIRS radiances with drifting buoy measurements, ship radiometric observations and mapped sea surface temperature products during the first six months after launch. The focus of the validation is on AIRS channel radiances in narrow spectral window regions located between 800-1250 cm(-1) and between 2500 and 2700 cm(-1) Simulated AIRS brightness temperatures are compared to in situ and satellite-based observations of sea surface temperature colocated in time and space, to demonstrate accuracies that can be achieved in clear atmospheres. An error budget, derived from single channel, single footprint matchups, indicates AIRS can be validated to better than 1% in absolute radiance (equivalent to 0.5 K in brightness temperature, at 300 K and 938 cm(-1)) during early mission operations. The eventual goal is to validate instrument radiances close to the demonstrated prelaunch calibration accuracy of about 0.4 % (equivalent to 0.2 K in brightness temperature, at 300 K and 938 cm(-1)). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Coral Gables, FL 33124 USA. RP Hagan, DE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 15 Z9 15 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 432 EP 441 DI 10.1109/TGRS.2002.808316 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600025 ER PT J AU King, MD Menzel, WP Kaufman, YJ Tanre, D Gao, BC Platnick, S Ackerman, SA Remer, LA Pincus, R Hubanks, PA AF King, MD Menzel, WP Kaufman, YJ Tanre, D Gao, BC Platnick, S Ackerman, SA Remer, LA Pincus, R Hubanks, PA TI Cloud and aerosol properties, precipitable water, and profiles of temperature and water vapor from MODIS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosols; aqua; clouds; meteorology; remote sensing; satellite applications; Terra; terrestrial atmosphere; water vapor ID RESOLUTION IMAGING SPECTRORADIOMETER; RETRIEVAL; SOUNDINGS; ALGORITHM; SOUNDER; 1ST AB The Moderate Resolution Imaging Spectroradiometer (MODIS) is an earth-viewing sensor that flies on the Earth Observing System Terra and Aqua satellites, launched in 1999 and 2002, respectively. MODIS scans a swath width of 2330 km that is sufficiently wide to provide nearly complete global coverage every two days from a polar-orbiting, sun-synchronous, platform at an altitude of 705 km. MODIS provides images in 36 spectral bands between 0.415 and 14.235 mum with spatial resolutions of 250 m (two bands), 500 m (five bands), and 1000 m (29 bands). These bands have been carefully selected to enable advanced studies of land, ocean, and atmospheric properties. Twenty-six bands are used to derive atmospheric properties such as cloud mask, atmospheric profiles, aerosol properties, total precipitable water, and cloud properties. In this paper we describe each of these atmospheric data products, including characteristics of each of these products such as file size, spatial resolution used in producing the product, and data availability. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Univ Wisconsin, NOAA, Natl Environm Satellite Data & Informat Serv, Madison, WI 53706 USA. Univ Sci & Technol Lille, Opt Atmospher Lab, Villeneuve Dascq, France. USN, Res Lab, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Lab Atmospheres, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA. NOAA, Climate Diagnost Ctr, Boulder, CO 80309 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP King, MD (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. RI Menzel, W. Paul/B-8306-2011; King, Michael/C-7153-2011; Ackerman, Steven/G-1640-2011; Platnick, Steven/J-9982-2014; Pincus, Robert/B-1723-2013 OI Menzel, W. Paul/0000-0001-5690-1201; King, Michael/0000-0003-2645-7298; Ackerman, Steven/0000-0002-4476-0269; Platnick, Steven/0000-0003-3964-3567; Pincus, Robert/0000-0002-0016-3470 NR 25 TC 527 Z9 540 U1 5 U2 69 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 442 EP 458 DI 10.1109/TGRS.2002.808226 PG 17 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600026 ER PT J AU Platnick, S King, MD Ackerman, SA Menzel, WP Baum, BA Riedi, JC Frey, RA AF Platnick, S King, MD Ackerman, SA Menzel, WP Baum, BA Riedi, JC Frey, RA TI The MODIS cloud products: Algorithms and examples from Terra SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE clouds; meteorology; remote sensing; satellite applications; terrestrial atmosphere ID IMAGING SPECTRORADIOMETER MODIS; AIRBORNE SIMULATOR IMAGERY; LIQUID WATER CLOUDS; SPECTROMETER MODIS; OPTICAL-THICKNESS; LIGHT-SCATTERING; ICE CRYSTALS; RETRIEVAL; SYSTEM; REFLECTANCE AB The Moderate Resolution Imaging Spectroradiometer (MODIS) is one of five instruments aboard the Terra Earth Observing System (EOS) platform launched in December 1999. After achieving final orbit, MODIS began earth observations in late February 2000 and has been acquiring data since that time. The instrument is also being flown on the Aqua spacecraft, launched in May 2002. A comprehensive set of remote sensing algorithms for cloud detection and the retrieval of cloud physical and optical properties have been developed by members of the MODIS atmosphere science team. The archived products from these algorithms have applications in climate change studies, climate modeling, numerical weather prediction, as well as fundamental atmospheric research. In addition to an extensive cloud mask, products include cloud-top properties (temperature, pressure, effective emissivity), cloud thermodynamic phase, cloud optical and microphysical parameters (optical thickness, effective particle radius, water path), as well as derived statistics. We will describe the various algorithms being used for the remote sensing of cloud properties from MODIS data with an emphasis on the pixel-level retrievals (referred to as Level-2 products), with 1-km or 5-km spatial resolution at nadir. An example of each Level-2 cloud product from a common data granule (5 min of data) off the coast of South America will be discussed. Future efforts will also be mentioned. Relevant points related to the global gridded statistics products (Level-3) are highlighted though additional details are given in an accompanying paper in this issue. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA. Univ Wisconsin, NOAA, Natl Environm Satellite Data & Informat Serv, Madison, WI 53706 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. RP Platnick, S (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RI Menzel, W. Paul/B-8306-2011; Baum, Bryan/B-7670-2011; King, Michael/C-7153-2011; Ackerman, Steven/G-1640-2011; Platnick, Steven/J-9982-2014 OI Menzel, W. Paul/0000-0001-5690-1201; Baum, Bryan/0000-0002-7193-2767; King, Michael/0000-0003-2645-7298; Ackerman, Steven/0000-0002-4476-0269; Platnick, Steven/0000-0003-3964-3567 NR 38 TC 893 Z9 909 U1 11 U2 120 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 459 EP 473 DI 10.1109/TGRS.2002.808301 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600027 ER PT J AU Gao, BC Yang, P Li, RR AF Gao, BC Yang, P Li, RR TI Detection of high clouds in polar regions during the daytime using the MODIS 1.375-mu m channel SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmosphere; cirrus cloud; remote sensing ID IMAGING SPECTROMETER DATA; COVER ANALYSIS; SURFACE; CLASSIFICATION AB Identification of clouds over earth's polar regions is difficult from satellite radiometric measurements in the visible and infrared (IR) atmospheric window regions because of the high albedos of snow- and ice-covered surfaces in the visible and the low-temperature contrast between the surface and the troposphere in the IR. The Moderate Resolution Imaging SpectroRadiometer (MODIS) on the Terra Spacecraft has a near-IR channel located within the strong water vapor absorption regions close to 1.38 mum. This channel was originally designed for remote sensing of high-altitude clouds in the tropical and mid-latitude regions. In this paper, we report that this channel is also quite useful for detecting high clouds in polar regions during the daytime. Comparisons with IR emission techniques for polar cloud detections are also presented. C1 USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. RP Gao, BC (reprint author), USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RI Yang, Ping/B-4590-2011 NR 22 TC 14 Z9 17 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 474 EP 481 DI 10.1109/TGRS.2002.808290 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 671ZB UT WOS:000182494600028 ER PT J AU Key, JR Santek, D Velden, CS Bormann, N Thepaut, JN Riishojgaard, LP Zhu, YQ Menzel, WP AF Key, JR Santek, D Velden, CS Bormann, N Thepaut, JN Riishojgaard, LP Zhu, YQ Menzel, WP TI Cloud-drift and water vapor winds in the polar regions from MODIS SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE MODIS; numerical weather prediction; polar meteorology; satellite applications; winds ID METEOSAT; FORECASTS; SYSTEM; IMPACT; IMAGES AB Wind products from geostationary satellites have been generated for over 20 years and are now used in numerical weather prediction systems. However, geostationary satellites are of limited utility poleward of the midlatitudes. This study demonstrates the feasibility of deriving high latitude tropospheric wind information from polar-orbiting satellites. The methodology employed is based on the algorithms currently used with geostationary satellites, modified for use with the Moderate-Resolution Imaging Spectroradiometer (MODIS) infrared window and water vapor bands. These bands provide wind information throughout the troposphere in both clear and cloudy conditions. The project presents some unique challenges, including the irregularity of temporal sampling, varying viewing geometries, and uncertainties in wind vector height assignment as a result of low atmospheric water vapor amounts and thin clouds. A 30-day case study dataset has been produced and is being used in model impact studies. Preliminary results are encouraging: when the MODIS winds are assimilated in the European Centre for Medium Range Weather Forecasts (ECMWF) system and the NASA Data Assimilation Office system, forecasts of the geopotential height for the Arctic, the Northern Hemisphere extratropics, and the Antarctic are improved significantly. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Madison, WI 53706 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Key, JR (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Madison, WI 53706 USA. RI Menzel, W. Paul/B-8306-2011; Key, Jeffrey/F-5597-2010 OI Menzel, W. Paul/0000-0001-5690-1201; Key, Jeffrey/0000-0001-6109-3050 NR 25 TC 39 Z9 40 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2003 VL 41 IS 2 BP 482 EP 492 DI 10.1109/TGRS.2002.808238 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 671ZB UT WOS:000182494600029 ER PT J AU Simons, RN Neudeck, PG AF Simons, RN Neudeck, PG TI Intermodulation-distortion performance of silicon-carbide Schottky-barrier RF mixer diodes SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE global positioning system (GPS); intermodulation distortion (IMD); mixers; Schottky diodes; silicon carbide (4H-SiC); VHF circuits AB This paper presents the fabrication and characterization of silicon carbide (SiC) Schottky-barrier mixer diodes of 25- and 50-mum diameter on a conducting 4H-SiC wafer. The single-balanced mixer circuits with a diode in each arm (two diodes total) were tested at 200 MHz (VHF) and 1.5 GHz [global positioning system (GPS)]. The experiments show that the conversion loss/input third-order intercept point (IP3) are 8.0 dB/+25 dBm and 7.5 dB/+22 dBm at these frequencies, respectively. The measured second-order intercept point (IP2) over the VHF frequency band is +38 dBm. The above conversion-loss values are about the same as that of commercially available single-balanced mixers with silicon Schottky-barrier diodes. However, to achieve a comparable input IP3 performance with Si Schottky-barrier diodes, a more complex mixer design involving double-balanced mixers with two diodes in each arm of a quad (eight diodes total) is required. Applications include RF-based navigational instruments on board commercial/general aviation aircraft and GPSs. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Simons, RN (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 12 TC 1 Z9 1 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD FEB PY 2003 VL 51 IS 2 BP 669 EP 672 DI 10.1109/TMTT.2002.807689 PN 2 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA 645MA UT WOS:000180980200010 ER PT J AU Sternberg, O Moller, KD Grebel, H Stewart, KP Henry, RM AF Sternberg, O Moller, KD Grebel, H Stewart, KP Henry, RM TI Inductive cross shaped metal meshes on silicon substrate SO INFRARED PHYSICS & TECHNOLOGY LA English DT Article AB Thin inductive metal meshes on silicon substrate have been studied in the infrared spectral region. The wavelength-dependent transmissions of meshes with cross shaped, square shaped, rectangular shaped openings, and meshes with grating pattern were measured. The resonance wavelength and width of resonance were determined for various geometries of the openings. The Micro-Stripes program was used for the calculation of resonance wavelength and width of resonance of cross shaped metal meshes and best-fit formulas were developed for the presentation of the data. The dependence on the shape of the opening was studied for free standing thin meshes and meshes on a silicon substrate. The Wood anomaly was studied experimentally for cross, square, rectangular shaped meshes and for gratings on silicon substrate. A simple model for the dependence of the Wood anomaly on the refractive index is presented. (C) 2002 Elsevier Science B.V. All rights reserved. C1 New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. New Jersey Inst Technol, Elect Imaging Ctr, Newark, NJ 07102 USA. New Jersey Inst Technol, Dept Elect Engn, Newark, NJ 07102 USA. USN, Res Lab, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moller, KD (reprint author), New Jersey Inst Technol, Dept Phys, Newark, NJ 07102 USA. NR 8 TC 0 Z9 0 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1350-4495 J9 INFRARED PHYS TECHN JI Infrared Phys. Technol. PD FEB PY 2003 VL 44 IS 1 BP 17 EP 25 AR PII S1350-4495(02)00181-0 DI 10.1016/S1350-4495(02)00181-0 PG 9 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 614YC UT WOS:000179218200003 ER PT J AU Jalobeanu, A Blanc-Feraud, L Zerubia, J AF Jalobeanu, A Blanc-Feraud, L Zerubia, J TI Satellite image deblurring using complex wavelet packets SO INTERNATIONAL JOURNAL OF COMPUTER VISION LA English DT Article DE deblurring; Bayesian estimation; complex wavelet packets; satellite and aerial images AB The deconvolution of blurred and noisy satellite images is an ill-posed inverse problem. Direct inversion leads to unacceptable noise amplification. Usually the problem is regularized during the inversion process. Recently, new approaches have been proposed, in which a rough deconvolution is followed by noise filtering in the wavelet transform domain. Herein, we have developed this second solution, by thresholding the coefficients of a new complex wavelet packet transform; all the parameters are automatically estimated. The use of complex wavelet packets enables translational invariance and improves directional selectivity, while remaining of complexity O(N). A new hybrid thresholding technique leads to high quality results, which exhibit both correctly restored textures and a high SNR in homogeneous areas. Compared to previous algorithms, the proposed method is faster, rotationally invariant and better takes into account the directions of the details and textures of the image, improving restoration. The images deconvolved in this way can be used as they are (the restoration step proposed here can be inserted directly in the acquisition chain), and they can also provide a starting point for an adaptive regularization method, enabling one to obtain sharper edges. C1 NASA, Ames Res Ctr, USRA RIACS, Moffett Field, CA 94035 USA. INRIA, CNRS INRIA UNSA, Project Ariana, F-06902 Sophia Antipolis, France. RP Jalobeanu, A (reprint author), NASA, Ames Res Ctr, USRA RIACS, MS 269-4, Moffett Field, CA 94035 USA. NR 28 TC 18 Z9 29 U1 0 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-5691 J9 INT J COMPUT VISION JI Int. J. Comput. Vis. PD FEB-MAR PY 2003 VL 51 IS 3 BP 205 EP 217 DI 10.1023/A:1021801918603 PG 13 WC Computer Science, Artificial Intelligence SC Computer Science GA 633TA UT WOS:000180297500003 ER PT J AU Gorla, RSR Pai, SS Rusick, JJ AF Gorla, RSR Pai, SS Rusick, JJ TI Probabilistic study of fluid structure interaction SO INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual Technical Meeting of the Society-of-Engineering-Science CY OCT 13-16, 2002 CL PENNSYLVANIA STATE UNIV, UNIVERSITY PK, PENNSYLVANIA SP Soc Engn Sci HO PENNSYLVANIA STATE UNIV DE probabilistic evaluation; fluid structure interaction; combustor liner; structural analysis; computational fluid dynamics ID TURBULENCE MODELS; 2-EQUATION AB A combustor liner was computationally simulated and probabilistically evaluated in view of the several uncertainties in the aerodynamic, structural, material and thermal variables that govern the combustor liner. The interconnection between the computational fluid dynamics code and the finite element structural analysis codes was necessary to couple the thermal profiles with structural design. The stresses and their variations were evaluated at critical points on the liner. Cumulative distribution functions and sensitivity factors were computed for stress responses due to the aerodynamic, mechanical and thermal random variables. It was observed that the inlet and exit temperatures have a lot of influence on the hoop stress. For prescribed values of inlet and exit temperatures, the Reynolds number of the flow, coefficient of thermal expansion, gas emissivity and absorptivity and thermal conductivity of the material have about the same impact on the hoop stress. These results can be used to quickly identify the most critical design variables in order to optimize the design and make it cost effective. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Cleveland State Univ, Dept Mech Engn, Cleveland, OH 44115 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Gorla, RSR (reprint author), Cleveland State Univ, Dept Mech Engn, Euclid Ave & E 24th St, Cleveland, OH 44115 USA. NR 14 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7225 J9 INT J ENG SCI JI Int. J. Eng. Sci. PD FEB-MAR PY 2003 VL 41 IS 3-5 BP 271 EP 282 AR PII S0020-7225(02)00205-7 DI 10.1016/S0020-7225(02)00205-7 PG 12 WC Engineering, Multidisciplinary SC Engineering GA 645MT UT WOS:000180982100006 ER PT J AU Chen, G Dresselhaus, MS Dresselhaus, G Fleurial, JP Caillat, T AF Chen, G Dresselhaus, MS Dresselhaus, G Fleurial, JP Caillat, T TI Recent developments in thermoelectric materials SO INTERNATIONAL MATERIALS REVIEWS LA English DT Review ID BISMUTH NANOWIRE ARRAYS; LATTICE THERMAL-CONDUCTIVITY; MULTILAYER THERMIONIC REFRIGERATION; TEMPERATURE TRANSPORT-PROPERTIES; STRAINED SI/GE SUPERLATTICES; QUANTUM-WELL STRUCTURES; THIN-FILM STRUCTURES; HEAT-CONDUCTION; GAAS/ALAS SUPERLATTICES; SKUTTERUDITE COMPOUNDS AB Efficient solid state energy conversion based on the Peltier effect for cooling and the Seebeck effect for power generation calls for materials with high electrical conductivity a, high Seebeck coefficient S, and low thermal conductivity k. Identifying materials with a high thermoelectric figure of merit Z(= S(2)sigma/k) has proven to be an extremely challenging task. After 30 years of slow progress, thermoelectric materials research experienced a resurgence, inspired by the developments of new concepts and theories to engineer electron and phonon transport in both nanostructures and bulk materials. This review provides a critical summary of some recent developments of new concepts and new materials. In nanostructures, quantum and classical size effects provide opportunities to tailor the electron and phonon transport through structural engineering. Quantum wells, superlattices, quantum wires, and quantum dots have been employed to change the band structure, energy levels, and density of states of electrons, and have led to improved energy conversion capability of charged carriers compared to those of their bulk counterparts. Interface reflection and the scattering of phonons in these nanostructures have been utilised to reduce the heat conduction loss. Increases in the thermoelectric figure of merit based on size effects for either electrons or phonons have been demonstrated. In bulk materials, new synthetic routes have led to engineered complex crystal structures with the desired phonon-glass electron-crystal behaviour. Recent studies on new materials have shown that dimensionless figure of merit (Zx temperature) values close to 1.5 could be obtained at elevated temperatures. These results have led to intensified scientific efforts to identify, design, engineer and characterise novel materials with a high potential for achieving ZT much greater than 1 near room temperature. C1 MIT, Dept Mech Engn, Cambridge, MA 02139 USA. MIT, Dept Elect Engn & Comp Sci, Dept Phys, Cambridge, MA 02139 USA. MIT, Francis Bitter Natl Magnet Lab, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP MIT, Dept Mech Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM gchen2@mit.edu RI Chen, Gang/J-1325-2014 OI Chen, Gang/0000-0002-3968-8530 NR 159 TC 496 Z9 506 U1 62 U2 592 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0950-6608 EI 1743-2804 J9 INT MATER REV JI Int. Mater. Rev. PD FEB PY 2003 VL 48 IS 1 BP 45 EP 66 DI 10.1179/095066003225010182 PG 22 WC Materials Science, Multidisciplinary SC Materials Science GA 659QB UT WOS:000181787400002 ER PT J AU Bourras, D Liu, WT Eymard, L Tang, WQ AF Bourras, D Liu, WT Eymard, L Tang, WQ TI Evaluation of latent heat flux fields from satellites and models during SEMAPHORE SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ATMOSPHERE RESPONSE EXPERIMENT; SEA-SURFACE TEMPERATURE; TOGA COARE; WIND-SPEED; OCEAN; LAYER; SSM/I; HUMIDITY; WATER AB Latent heat fluxes were derived from satellite observations in the region of Structure des Echanges Mer-Atmosphere, Propriete's des Heterogeneites Oceaniques: Recherche Experimentale (SEMAPHORE), which was conducted near the Azores islands in the North Atlantic Ocean in autumn of 1993. The satellite fluxes were compared with output fields of two atmospheric circulation models and in situ measurements. The rms error of the instantaneous satellite fluxes is between 35 and 40 W m(-2) and the bias is 60-85 W m(-2). The large bias is mainly attributed to a bias in satellite-derived atmospheric humidity and is related to the particular shape of the vertical humidity profiles during SEMAPHORE. The bias in humidity implies that the range of estimated fluxes is smaller than the range of ship fluxes, by 34%-38%. The rms errors for fluxes from models are 30-35 W m(-2), and the biases are smaller than the biases in satellite fluxes (14-18 W m(-2)). Two case studies suggest that the satellites detect horizontal gradients of wind speed and specific humidity if the magnitude of the gradients exceeds a detection threshold, which is 1.27 g kg(-1) (100 km)(-1) for specific humidity and between 0.35 and 0.82 m s(-1) (30 km)(-1) for wind speed. In contrast, the accuracy of the spatial gradients of bulk variables from models always varies as a function of the location and number of assimilated observations. A comparison between monthly fluxes from satellites and models reveals that satellite-derived flux anomaly fields are consistent with reanalyzed fields, whereas operational model products lack part of the mesoscale structures present in the satellite fields. C1 CETP, IPSL, CNRS, F-78140 Velizy Villacoublay, France. Ctr Etud Environm Terr & Planetaires, Velizy Villacoublay, France. CALTECH, Jet Prop Lab, NASA, Pasadena, CA USA. RP Bourras, D (reprint author), CETP, IPSL, CNRS, 10-12 Ave Europe, F-78140 Velizy Villacoublay, France. NR 22 TC 20 Z9 20 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 2003 VL 42 IS 2 BP 227 EP 239 DI 10.1175/1520-0450(2003)042<0227:EOLHFF>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 640BU UT WOS:000180667200005 ER PT J AU Loeb, NG Manalo-Smith, N Kato, S Miller, WF Gupta, SK Minnis, P Wielicki, BA AF Loeb, NG Manalo-Smith, N Kato, S Miller, WF Gupta, SK Minnis, P Wielicki, BA TI Angular distribution models for top-of-atmosphere radiative flux estimation from the clouds and the Earth's Radiant Energy System instrument on the Tropical Rainfall Measuring Mission satellite. part I: Methodology SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID REFLECTED SOLAR RADIANCES; BOUNDARY-LAYER CLOUDS; BIDIRECTIONAL REFLECTANCE; SURFACE; PARAMETERIZATION; IDENTIFICATION; ANISOTROPY; ABSORPTION; AEROSOLS; IMAGERY AB Clouds and the Earth's Radiant Energy System (CERES) investigates the critical role that clouds and aerosols play in modulating the radiative energy flow within the Earth-atmosphere system. CERES builds upon the foundation laid by previous missions, such as the Earth Radiation Budget Experiment, to provide highly accurate top-of-atmosphere (TOA) radiative fluxes together with coincident cloud and aerosol properties inferred from high-resolution imager measurements. This paper describes the method used to construct empirical angular distribution models (ADMs) for estimating shortwave, longwave, and window TOA radiative fluxes from CERES radiance measurements on board the Tropical Rainfall Measuring Mission satellite. To construct the ADMs, multiangle CERES measurements are combined with coincident high-resolution Visible Infrared Scanner measurements and meteorological parameters from the European Centre for Medium-Range Weather Forecasts data assimilation product. The ADMs are stratified by scene types defined by parameters that have a strong influence on the angular dependence of Earth's radiation field at the TOA. Examples of how the new CERES ADMs depend upon the imager-based parameters are provided together with comparisons with existing models. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 59 TC 148 Z9 149 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 2003 VL 42 IS 2 BP 240 EP 265 DI 10.1175/1520-0450(2003)042<0240:ADMFTO>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 640BU UT WOS:000180667200006 ER PT J AU Durden, SL Li, L Im, E Yueh, SH AF Durden, SL Li, L Im, E Yueh, SH TI A surface reference technique for airborne Doppler radar measurements in hurricanes SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID TRMM PRECIPITATION RADAR; PATH ATTENUATION; MODEL FUNCTION; CROSS-SECTION; TOGA COARE; KU-BAND; OCEAN; RAIN; GHZ; ALGORITHM AB The operational algorithm for rainfall retrieval from the Tropical Rainfall Measuring Mission (TRMM) precipitation radar data requires a measurement of the path-integrated attenuation (PIA) as a constraint. This constraint is derived via the surface reference technique, whereby a measurement of the ocean surface in a raining area is compared with the ocean surface backscatter in a neighboring clear area. This method assumes that the surface backscatter difference is due only to the presence of rain, although variation in surface winds could also cause differences in the reference and rain measurements. An alternative surface reference method is to use a measurement of the surface winds and a backscatter model to predict the rain-free, or reference, cross section. Such an approach is developed here for airborne Doppler radar measurements in hurricanes. This approach provides an independent measurement of the reference backscatter, which is compared with the standard clear-air reference. The mean difference between the standard and Doppler-derived PIA is less than or equal to 1 dB; the rms difference is in the range 0.9-2.6 dB. In deriving the model function for backscatter estimation from wind measurements, the authors also find that the dependence of ocean backscatter on wind appears to saturate at high wind speeds at 25degrees incidence. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Durden, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 29 TC 8 Z9 8 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD FEB PY 2003 VL 20 IS 2 BP 269 EP 275 DI 10.1175/1520-0426(2003)020<0269:ASRTFA>2.0.CO;2 PG 7 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 640BX UT WOS:000180667600004 ER PT J AU Obrou, OK Radicella, SM Adeniyi, JO AF Obrou, OK Radicella, SM Adeniyi, JO TI The equatorial electrojet and the profile parameters B0 and B1 around midday SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE equatorial ionosphere; equatorial electrojet; electron density profiles ID MAGNETIC MEASUREMENTS; CURRENTS; REGION; MODEL; RADAR AB This study presents the results of the comparison of B0, B1 and hmF2 With DeltaH. B0 and B1 are parameters used in the international reference ionosphere model for the calculation of the F region bottom side profiles. The parameter DeltaH obtained from the magnetic data recorded during the International Equatorial Electrojet Year (IEEY) in West Africa is used to describe the strength of the equatorial electrojet. This work covers the years 1993 and 1994, two years of low and moderate solar activity. The result shows that the electric field (E), which drives the equatorial electrojet, plays a major role in the variation of the thickness and the height of the F2 layer. However, the variation of the shape of the bottomside F2 is not sensitive to the electric field. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Int Ctr Theoret Phys, Trieste, Italy. Univ Cocody, UFR SSMT, Lab Phys Atmosphere, Abidjan, Cote Ivoire. Univ Ilorin, Dept Phys, Ilorin, Nigeria. RP Obrou, OK (reprint author), NASA, Goddard Space Flight Ctr, Code 632, Greenbelt, MD 20771 USA. NR 16 TC 7 Z9 7 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 2003 VL 65 IS 3 BP 299 EP 304 DI 10.1016/S1364-6826(02)00336-X PG 6 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 650EL UT WOS:000181249800005 ER PT J AU Wang, DY Stallcop, JR Huo, WM Dateo, CE Schwenke, DW Partridge, H AF Wang, DY Stallcop, JR Huo, WM Dateo, CE Schwenke, DW Partridge, H TI Quantal study of the exchange reaction for N+N-2 using an ab initio potential energy surface SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RATE COEFFICIENTS; CROSS-SECTIONS; WAVE-FUNCTIONS; BASIS-SETS; NITROGEN; ATOMS; COLLISIONS; MOLECULES; HYDROGEN; DYNAMICS AB The N+N-2 exchange rate is calculated using a time-dependent quantum dynamics method on a newly determined ab initio potential energy surface (PES) for the ground (4)A" state. This ab initio PES shows a double barrier feature in the interaction region with the barrier height at 47.2 kcal/mol, and a shallow well between these two barriers, with the minimum at 43.7 kcal/mol. A quantum dynamics wave packet calculation has been carried out using the fitted PES to compute the cumulative reaction probability for the exchange reaction of N+N-2(J=0). The J-K shift method is then employed to obtain the rate constant for this reaction. The calculated rate constant is compared with experimental data and a recent quasiclassical calculation using a London-Eyring-Polanyi-Sato PES. Significant differences are found between the present and quasiclassical results. The present rate calculation is the first accurate three-dimensional quantal dynamics study for the N+N-2 reaction system and the ab initio PES reported here is the first such surface for N-3. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94087 USA. RP Wang, DY (reprint author), NASA, Ames Res Ctr, MS T27B-1, Moffett Field, CA 94035 USA. RI schwenke, david/I-3564-2013 NR 28 TC 41 Z9 41 U1 1 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 2003 VL 118 IS 5 BP 2186 EP 2189 DI 10.1063/1.1534092 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 638PR UT WOS:000180579900020 ER PT J AU Weill, A Eymard, L Caniaux, G Hauser, D Planton, S Dupuis, H Brut, A Guerin, C Nacass, P Butet, A Cloche, S Pedreros, R Durand, P Bourras, D Giordani, H Lachaud, G Bouhours, G AF Weill, A Eymard, L Caniaux, G Hauser, D Planton, S Dupuis, H Brut, A Guerin, C Nacass, P Butet, A Cloche, S Pedreros, R Durand, P Bourras, D Giordani, H Lachaud, G Bouhours, G TI Toward a better determination of turbulent air-sea fluxes from several experiments SO JOURNAL OF CLIMATE LA English DT Article ID STRATOCUMULUS TRANSITION EXPERIMENT; ATMOSPHERIC BOUNDARY-LAYER; SEMAPHORE EXPERIMENT; WIND STRESS; SURFACE FLUXES; HEAT-FLUX; ATLANTIC; OCEAN; CIRCULATION; BUOY AB An accurate determination of turbulent exchanges between the ocean and the atmosphere is a prerequisite to identify and assess the mechanisms of interaction that control part of the variability in the two media over a wide range of spatial and temporal scales. An extended dataset for estimating air-sea fluxes (representing nearly 5700 h of turbulence measurements) has been collected since 1992 during six dedicated experiments performed in the Atlantic Ocean and the Mediterranean Sea. This paper presents the methodology used through the successive experiments to progress in this field. The major developments concern (i) flux instrumentation, with the deployment of a microwave refractometer to get the latent heat flux in most meteorological conditions; (ii) the analysis of airflow distortion effects around the ship structure and sensors through both computational fluid dynamics and physical simulations in a water tank, then the derivation of correction for these effects; (iii) the application of both inertial dissipation and eddy-correlation methods from the various experiments, allowing the authors to assess and discuss flux-determination methods on ships, and particularly bulk parameterization; (iv) the validation and analysis of mesoscale surface flux fields from models and satellites by using ship data, showing some deficiencies in operational model fields from ECMWF, the need of high-quality fluxes to interpret ocean-atmosphere exchanges, and the potential advantage of satellite retrieval methods. Further analysis of these datasets is being performed in a unique database (the ALBATROS project, open to the international scientific community). It will include refinement of airflow distortion correction and reprocessing of earlier datasets, the investigation of fluxes under specific conditions (low wind), and the effect of sea state among others. It will also contribute to further validation and improvements of satellite retrievals in various climatic/meteorological conditions. C1 CETP IPSL CNRS, F-78140 Velizy Villacoublay, France. Meteo France CNRM, Toulouse, France. DGO, Talence, France. Meteo France CAM, Bretigny Sur Orge, France. NASA, Jet Propuls Lab, Pasadena, CA USA. RP Eymard, L (reprint author), CETP IPSL CNRS, F-78140 Velizy Villacoublay, France. RI PLANTON, Serge/L-3112-2016; tournadre, jean/F-8402-2010 OI tournadre, jean/0000-0003-1159-4388 NR 59 TC 34 Z9 34 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 2003 VL 16 IS 4 BP 600 EP 618 DI 10.1175/1520-0442(2003)016<0600:TABDOT>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 644HP UT WOS:000180912100004 ER PT J AU Sui, CH Li, XF Rienecker, MM Lau, KM Laszlo, I Pinker, RT AF Sui, CH Li, XF Rienecker, MM Lau, KM Laszlo, I Pinker, RT TI The role of daily surface forcing in the upper ocean over the tropical Pacific: A numerical study SO JOURNAL OF CLIMATE LA English DT Article ID AIR-SEA INTERACTION; EQUATORIAL PACIFIC; SOLAR-RADIATION; EL-NINO; SOUTHERN OSCILLATION; WESTERN PACIFIC; HEAT-BALANCE; TOGA COARE; NCAR CCM2; WARM POOL AB The impacts of high-frequency surface forcing in the upper ocean over the equatorial Pacific are investigated using a nonlinear reduced-gravity isopycnal ocean circulation model forced by daily and monthly mean forcing. The simulated sea surface temperature (SST) in the daily forcing experiment is colder than that in the monthly forcing experiment near the equator. A mixed layer heat budget calculation shows that the net surface heat flux is primarily responsible for the SST difference in the western Pacific, while zonal advection accounts for the SST difference in the eastern Pacific where other budget terms are large but canceling each other. The daily forcing primarily enhances vertical mixing that reduces the vertical shear of the upper ocean. It also changes the net heat into the ocean through two contrasting processes: one is the increased surface latent heat loss induced by transient winds and the other is colder SST due to stronger mixing, which further reduces heat loss at the surface. As a result, the annual mean net surface heat flux into the ocean is reduced and the meridional thermal advection is weaker. The daily forcing also impacts the variation of the thermocline through a changing mixed layer depth so that the temperature in the simulation with the daily forcing is warmer around the thermocline. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, NESDIS, Off Res & Applicat, Camp Springs, MD USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. RP Sui, CH (reprint author), Natl Cent Univ, Inst Hydrol Sci, 300 Junda Rd, Tao Yuan 320, Taiwan. EM sui@cc.ncu.edu.tw RI Laszlo, Istvan/F-5603-2010; Pinker, Rachel/F-6565-2010; Li, Xiaofan/F-5605-2010; Li, Xiaofan/G-2094-2014; Lau, William /E-1510-2012; OI Laszlo, Istvan/0000-0002-5747-9708; Lau, William /0000-0002-3587-3691; SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 46 TC 10 Z9 10 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD FEB PY 2003 VL 16 IS 4 BP 756 EP 766 DI 10.1175/1520-0442(2003)016<0756:TRODSF>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 644HP UT WOS:000180912100016 ER PT J AU Diedrichsen, J Ivry, RB Hazeltine, E Kennerley, S Cohen, A AF Diedrichsen, J Ivry, RB Hazeltine, E Kennerley, S Cohen, A TI Bimanual interference associated with the selection of target locations SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID DISCRETE FINGER RESPONSES; DUAL-TASK INTERFERENCE; STRUCTURAL CONSTRAINTS; CALLOSOTOMY PATIENTS; DIFFERENT AMPLITUDES; MOVEMENT AMPLITUDES; TIME-COURSE; CROSS-TALK; COORDINATION; PERFORMANCE AB Four experiments were conducted to identify the locus of interference observed during the preparation of bimanual reaching movements. Target locations were specified by color, and the right-hand and left-hand targets could be either the same or a different color. Movements of different amplitudes (Experiment 1) or different directions (Experiment 2) to targets of the same color were initiated more quickly than symmetric movements to targets of different colors. These results indicate that costs observed during bimanual movements arise during target selection rather than during motor programming. Experiments 3 and 4 further examined the interference associated with target selection. Reaction time costs were found with unimanual movements when the target was presented among distractors associated with responses for the other hand. Interference observed during bimanual reaching appears to reflect difficulty in segregating the response rules assigned to each hand. C1 Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Hebrew Univ Jerusalem, Dept Psychol, Jerusalem, Israel. RP Diedrichsen, J (reprint author), Univ Calif Berkeley, Dept Psychol, Tolman Hall 1650, Berkeley, CA 94720 USA. RI Diedrichsen, Jorn/A-7789-2010 OI Diedrichsen, Jorn/0000-0003-0264-8532 FU NINDS NIH HHS [NS 30256, NS 17778] NR 44 TC 43 Z9 43 U1 1 U2 6 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0096-1523 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD FEB PY 2003 VL 29 IS 1 BP 64 EP 77 DI 10.1037/0096-1523.29.1.64 PG 14 WC Psychology; Psychology, Experimental SC Psychology GA 650YA UT WOS:000181291000005 PM 12669748 ER PT J AU Byun, SH AF Byun, SH TI Satellite orbit determination using triple-differenced GPS carrier phase in pure kinematic mode SO JOURNAL OF GEODESY LA English DT Article DE kinematic; orbit determination; triple difference; global positioning system AB A new algorithm and computer program, KODAC (Kinematic Orbit Determination And Comparison), was developed for precise satellite orbit determination using a kinematic approach with the ionospheric-free triple-differenced (TD) global positioning system (GPS) carrier phase as the main observable. Epoch-by-epoch satellite positions are estimated by assuming that the GPS satellite ephemerides, ground station positions, and the time series of wet tropospheric zenith delay are known in advance. The technique was demonstrated with TOPEX/POSEIDON GPS data, which gave a final radial root-mean-square orbit accuracy of 8 cm with respect to a fully dynamic solution. This new approach has the advantage of having consistent orbit accuracy regardless of satellite altitude due to its non-dynamic approach. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Byun, SH (reprint author), CALTECH, Jet Prop Lab, MS 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM shb@cobra.jpl.nasa.gov NR 14 TC 5 Z9 10 U1 1 U2 4 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-7714 J9 J GEODESY JI J. Geodesy PD FEB PY 2003 VL 76 IS 9-10 BP 569 EP 585 DI 10.1007/s00190-002-0279-0 PG 17 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 657QY UT WOS:000181678900008 ER PT J AU Mohr, KI Baker, RD Tao, WK Famiglietti, JS AF Mohr, KI Baker, RD Tao, WK Famiglietti, JS TI The sensitivity of West African convective line water budgets to land cover SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID TROPICAL SQUALL LINES; 23 JUNE 1981; MOIST CONVECTION; BOUNDARY-LAYER; SOIL-MOISTURE; PRECIPITATION; PARAMETERIZATION; ORGANIZATION; MIDLATITUDE; SIMULATIONS AB This study used a two-dimensional coupled land-atmosphere (cloud resolving) model to investigate the influence of land cover on the water budgets of convective lines in West Africa. Study simulations used the same initial sounding and one of three different land covers: a sparsely vegetated semidesert, a grassy savanna, and a dense evergreen broadleaf forest. All simulations began at midnight and ran for 24 h to capture a full diurnal cycle. During the morning, the forest had the highest latent heat flux, the shallowest, moistest, slowest growing boundary layer, and more convective available potential energy than the savanna and semidesert. Although the savanna and forest environments produced virtually the same total rainfall mass (semidesert 18%), the spatial and temporal patterns of the rainfall were significantly different and can be attributed to the boundary layer evolution. The forest produced numerous convective cells with very high rain rates mainly during the early afternoon. During the morning, the savanna built up less but still significant amounts of convective available potential energy and enough convective inhibition so that the strongest convection in the savanna did not occur until late afternoon. This timing resulted in the largest, most intense convective line of the three land covers. C1 SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA. Austin Coll, Dept Phys, Sherman, TX 75090 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. RP Mohr, KI (reprint author), SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA. RI Mohr, Karen/E-4331-2012 NR 29 TC 25 Z9 26 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD FEB PY 2003 VL 4 IS 1 BP 62 EP 76 DI 10.1175/1525-7541(2003)004<0062:TSOWAC>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 642VX UT WOS:000180827100005 ER PT J AU Han, S Jin, W Tang, T Li, C Zhang, DH Liu, XL Han, J Zhou, CW AF Han, S Jin, W Tang, T Li, C Zhang, DH Liu, XL Han, J Zhou, CW TI Controlled growth of gallium nitride single-crystal nanowires using a chemical vapor deposition method SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID LIGHT-EMITTING-DIODES; GAN NANOWIRES; CATALYTIC GROWTH; SYNTHETIC ROUTE; LASER-DIODES; SILICON; NANOTUBES; NANORODS AB Chemical vapor deposition (CVD) using gold nanoparticles as the catalyst to grow high-quality single-crystal gallium nitride nanowires was developed.. This method enables control over several important aspects of the growth, including control of the nanowire diameter by using monodispersed gold clusters, control of the nanowire location via e-beam patterning of the catalyst sites, and control of the nanowire orientation via epitaxial growth on a-plane sapphire substrates. Our work opens up new ways to use GaN nanowires as nanobuilding blocks. C1 Univ So Calif, Dept Elect Engn Electrophys, Los Angeles, CA 90089 USA. NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 USA. RP Zhou, CW (reprint author), Univ So Calif, Dept Elect Engn Electrophys, Los Angeles, CA 90089 USA. RI Tang, Tao/C-8123-2011; Zhou, Chongwu/F-7483-2010 NR 26 TC 49 Z9 49 U1 0 U2 22 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 2003 VL 18 IS 2 BP 245 EP 249 DI 10.1557/JMR.2003.0033 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 643XY UT WOS:000180889900001 ER PT J AU Widicus, SL Drouin, BJ Dyl, KA Blake, GA AF Widicus, SL Drouin, BJ Dyl, KA Blake, GA TI Millimeter wavelength measurements of the rotational spectrum of 2-aminoethanol SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID INTERSTELLAR AB Aminoethanol is a predicted precursor to the amino acid alanine in the interstellar medium and is therefore of great interest for observational studies. However, previous work involving the rotational spectrum of this molecule is limited to centimeter wavelengths and additional laboratory work is necessary to support astronomical heterodyne spectroscopy, This work presents the Doppler-limited rotational spectrum of aminoethanol measured in selected regions between 72 and 305Gliz. Measurements of ground state and V-27 transitions have been extended up to J = 51 and J 43. respectively. Additional rotational transitions were hot bands, resulting in improved rotational and Centrifugal distortion constants assigned for the v(25), v(26), v(25) + v(27), 2v(27), and v(26) + v(27) for these states. (C) 2003 Elsevier Science (USA). All rights reserved. C1 CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Widicus, SL (reprint author), CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. NR 11 TC 13 Z9 13 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD FEB PY 2003 VL 217 IS 2 BP 278 EP 281 DI 10.1016/S0022-2852(02)00056-5 PG 4 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 655NK UT WOS:000181558800013 ER PT J AU Arepalli, S Fischer, J AF Arepalli, S Fischer, J TI A special issue on carbon nanotubes SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Editorial Material C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Penn, Philadelphia, PA 19104 USA. RP Arepalli, S (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RI Arepalli, Sivaram/A-5372-2010 NR 0 TC 1 Z9 1 U1 0 U2 3 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB-APR PY 2003 VL 3 IS 1-2 BP 1 EP 2 PG 2 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 694UN UT WOS:000183793100001 ER PT J AU Scott, CD Povitsky, A Dateo, C Gokcen, T Willis, PA Smalley, RE AF Scott, CD Povitsky, A Dateo, C Gokcen, T Willis, PA Smalley, RE TI Iron catalyst chemistry in modeling a high-pressure carbon monoxide nanotube reactor SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE single-wall carbon nanotubes; HiPCo; nanotube reactor; iron catalyst ID HIPCO PROCESS; KINETICS AB The high-pressure carbon monoxide (HiPco) technique for producing single-wall carbon nanotubes (SWNTs) is analyzed with the use of a chemical reaction model coupled with flow properties calculated along streamlines, calculated by the FLUENT code for pure carbon monoxide. Cold iron pentacarbonyl, diluted in CO at about 30 atmospheres, is injected into a conical mixing zone, where hot CO is also introduced via three jets at 30degrees with respect to the axis. Hot CO decomposes the Fe(CO), to release atomic Fe. Then iron nucleates and forms clusters that catalyze the formation of SWNTs by a disproportionation reaction (Boudouard) of CO on Fe-containing clusters. Alternative nucleation rates are estimated from the theory of hard sphere collision dynamics with an activation energy barrier. The rate coefficient for carbon nanotube growth is estimated from activation energies in the literature. The calculated growth was found be about an order of magnitude greater than measured, regardless of the nucleation rate. A study of cluster formation in an incubation zone prior to injection into the reactor shows that direct dimer formation from Fe atoms is not as important as formation via an exchange reaction of Fe with CO in FeCO. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23665 USA. NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77251 USA. RP Scott, CD (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RI Willis, Peter/I-6621-2012 NR 13 TC 27 Z9 27 U1 1 U2 6 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB-APR PY 2003 VL 3 IS 1-2 BP 63 EP 73 DI 10.1166/jnn.2003.164 PG 11 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 694UN UT WOS:000183793100006 PM 12908231 ER PT J AU Scott, CD Smalley, RE AF Scott, CD Smalley, RE TI Effects of carbonyl bond, metal cluster dissociation, and evaporation rates on predictions of nanotube production in high-pressure carbon monoxide SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE singte-wall carbon nanotubes; HiPGo; nanotube production cluster model AB The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon, nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the coformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77251 USA. RP Scott, CD (reprint author), NASA, Lyndon B Johnson Space Ctr, ES4, Houston, TX 77058 USA. NR 10 TC 14 Z9 14 U1 2 U2 5 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB-APR PY 2003 VL 3 IS 1-2 BP 75 EP 79 DI 10.1166/jnn.2003.165 PG 5 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 694UN UT WOS:000183793100007 PM 12908232 ER PT J AU Sadanadan, B Savage, T Bhattacharya, S Tritt, T Cassell, A Meyyappan, M Dai, ZR Wang, ZL Zidan, R Rao, AM AF Sadanadan, B Savage, T Bhattacharya, S Tritt, T Cassell, A Meyyappan, M Dai, ZR Wang, ZL Zidan, R Rao, AM TI Synthesis and thermoelectric power of nitrogen-doped carbon nanotubes SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE carbon nanotubes; synthesis; nitrogen doping; thermoelectric power; SEM; HRTEM ID CHEMICAL-VAPOR-DEPOSITION; ELECTRONIC-PROPERTIES; ELECTRICAL-TRANSPORT; GROWTH; PYROLYSIS AB We have previously shown that high-purity multiwalled carbon nanotubes (pristine MWNTs) can be prepared from a mixture of xylene-ferrocene,(99 at% C:1 at% Fe) inside a quartz tube reactor operating at similar to700 degreesC. In a similar process, similar to3 g of melamine (C3H6N6) was introduced during the growth of MWNTs to prepare nitrogen-doped nanotubes. The structural and electronic properties of nitrogen-doped MWNTs were determined by scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), and thermopower measurements. The individual nitrogen-doped nanotube exhibits a bamboo-like structure and comprises 6-16 tube walls, as evidenced by HRTEM studies. The EELS measurements yielded an average nitrogen content of similar to5 at% in the doped tubes. The thermoelectric power data of nitrogen-doped MWNTs remained negative even after exposure to oxygen for an extended period of time, suggesting that nitrogen doping of MWNTs renders them n-type, consistent with scanning tunneling spectroscopic studies on similar nanotubes. C1 Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Georgia Inst Technol, Dept Mat Sci & Engn, Atlanta, GA 30332 USA. Savannah River Technol Ctr, Aiken, SC USA. RP Rao, AM (reprint author), Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. RI Dai, Zurong/E-6732-2010; Wang, Zhong Lin/E-2176-2011 OI Wang, Zhong Lin/0000-0002-5530-0380 NR 24 TC 15 Z9 15 U1 1 U2 17 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB-APR PY 2003 VL 3 IS 1-2 BP 99 EP 103 DI 10.1166/jnn.2003.186 PG 5 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 694UN UT WOS:000183793100011 PM 12908236 ER PT J AU Nguyen, CV Delziet, L Matthews, K Chen, B Meyyappan, M AF Nguyen, CV Delziet, L Matthews, K Chen, B Meyyappan, M TI Purification process for vertically aligned carbon nanofibers SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE carbon nanofibers; Raman spectroscopy; purification; vertical alignment ID CHEMICAL-VAPOR-DEPOSITION; NANOTUBES; GROWTH; ARRAYS AB Individual, free-standing, vertically aligned multiwall carbon nanotubes or nanofibers are ideal for sensor and electrode applications. Our plasma-enhanced chemical vapor deposition techniques for producing free-standing and vertically aligned carbon nanofibers use catalyst particles at the tip of the fiber. Here we present a simple purification process for the removal of iron catalyst particles at the tip of vertically aligned carbon nanofibers derived by plasma-enhanced chemical vapor deposition. The first step involves thermal oxidation in air, at temperatures of 200-400 degreesC, resulting in the physical swelling of the iron particles from the formation of iron oxide. Subsequently, the complete removal of the iron oxide particles is achieved with diluted acid (12% HCl). The purification process appears to be very efficient at removing all of the iron catalyst particles. Electron microscopy images and Raman spectroscopy data indicate that the purification process does not damage the graphitic structure of the nanotubes. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Nguyen, CV (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 20 TC 6 Z9 6 U1 0 U2 4 PU AMER SCIENTIFIC PUBLISHERS PI VALENCIA PA 26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB-APR PY 2003 VL 3 IS 1-2 BP 121 EP 125 DI 10.1166/jnn.2003.178 PG 5 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 694UN UT WOS:000183793100014 PM 12908239 ER PT J AU Fu, LL AF Fu, LL TI Wind-forced intraseasonal sea level variability of the extratropical oceans SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID DRIVEN CURRENT FLUCTUATIONS; WESTERN NORTH-ATLANTIC; SATELLITE ALTIMETRY; TOPEX/POSEIDON ALTIMETER; PACIFIC; CIRCULATION; WAVES; OSCILLATIONS AB Seven years' worth of sea level observations from the TOPEX/Poseidon altimeters and wind observations from the European Remote-Sensing Satellites (ERS-1/2) scatterometers were used to investigate the dynamics of large-scale intraseasonal sea level variability at mid- and high latitudes. Coherent patterns of sea level variability with spatial scales of 1000 km and timescales of 20 days to 1 year are identified in three particular regions: the Bellingshausen Basin west of Drake Passage, the Australian-Antarctic Basin, and the central North Pacific Ocean (30degrees-50degreesN) near the date line. Significant coherence is found between wind stress curl and the sea level variability. A simple barotropic vorticity equation, in which the time rate of relative vorticity variation is balanced by the wind stress curl and a damping term, is used to simulate the sea level anomalies with a significant degree of correlation with the observations. Although the coherence between the simulation and the observation is significant from periods of 30 days to 1 yr, the variance of the simulation is too low at periods shorter than 100 days. This is probably caused by the errors in the wind forcing as well as the other terms neglected in the vorticity equation. The simulation requires a damping timescale generally longer than 20 days, consistent with theoretical estimates of the dissipation timescales of a frictional bottom boundary layer. In the Bellingshausen Basin, the phase of the coherence between sea level and wind stress curl also shows dependence on frequency according to the dissipation mechanism and estimated damping timescales. However, the results at the other two locations are less conclusive. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RP Fu, LL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91101 USA. NR 32 TC 36 Z9 36 U1 0 U2 1 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 2003 VL 33 IS 2 BP 436 EP 449 DI 10.1175/1520-0485(2003)033<0436:WFISLV>2.0.CO;2 PG 14 WC Oceanography SC Oceanography GA 642VW UT WOS:000180827000008 ER PT J AU Devi, VM Benner, DC Smith, MAH Rinsland, CP AF Devi, VM Benner, DC Smith, MAH Rinsland, CP TI Nitrogen broadening and shift coefficients in the 4.2-4.5-mu m bands of CO2 SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE CO2; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; spectral lineshape ID 4.3-MU-M REGION; PRESSURE; (CO2)-C-12-O-16; ABSORPTION; STRENGTHS; MIXTURES; SPECTRA; NU-3 AB In this study we report the first high-resolution measurements of pressure broadening and pressure-induced shift coefficients due to nitrogen for rovibrational transitions in the v(3) band of C-13(16) O-2. N-2 broadening and shift coefficients Of v(3)(12)C(16)O(2) transitions were also measured. In addition, nitrogen-broadening coefficients for many transitions in the v(3) + v(2) - v(2) hot band of 13C16 02 as well as the v(3) band of (COO)-C-13-O-16-O-18 were also determined. The results were obtained by analyzing five high-resolution (0.0028 cm(-1)) room temperature laboratory absorption spectra with a multispectrum nonlinear least-squares spectral fitting technique. The data were recorded with the McMath-Pierce Fourier transform spectrometer of the National Solar Observatory on Kitt Peak using a 4.08 cm sample cell, total pressures up to 470 Torr, and a 90% C-13-enriched CO2 sample. For the pressure-broadened spectra the (CO2)-C-13-O-16 volume-mixing ratios were less than or equal to 0.5%. Similar to broadening coefficients, the measured pressure shift coefficients were also found to be transition dependent. However, the shift coefficients were different in the P and R branch lines with the same rotational quantum number, J. The measured nitrogen-broadening coefficients range from 0.0960 to 0.0643 cm(-1) atm(-1) at 296 K. The measured shift coefficients were all negative and varied between 0 and -0.0036 cm(-1) atm(-1). The results obtained are compared with other values reported in the literature. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 25 TC 14 Z9 14 U1 0 U2 4 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 1 PY 2003 VL 76 IS 3-4 BP 289 EP 307 AR PII S0022-4073(02)00057-2 DI 10.1016/S0022-4073(02)00057-2 PG 19 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 618CV UT WOS:000179401300003 ER PT J AU Devi, VM Benner, DC Smith, MAH Brown, LR Dulick, M AF Devi, VM Benner, DC Smith, MAH Brown, LR Dulick, M TI Absolute intensity measurements of the (CO2)-C-12-O-16 laser bands near 10 mu m SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE CO2; CO2 laser bands; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; absolute intensity ID REGION; COEFFICIENTS; DATABASE; LINES; CO2; N2O AB Line intensities of the two (CO2)-C-12-O-16 laser bands (v(3)-v(1) and v(3)-2v(2)(0)) centered near 960.9 and 1063.7 cm(-1), respectively, were obtained from analysis of 30 room temperature long path laboratory absorption spectra recorded at 0.0028 and 0.0053 cm(-1) resolution with the McMath-Pierce Fourier transform spectrometer at the National Solar Observatory (located on Kitt Peak). The spectra were analyzed simultaneously with the multispectrum nonlinear least-squares fitting procedure. The measured line intensities were further analyzed to derive the vibrational band intensities and Herman-Wallis coefficients. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Atmospher Sci, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Natl Solar Observ, Tucson, AZ 85726 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 18 TC 11 Z9 11 U1 0 U2 2 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 1 PY 2003 VL 76 IS 3-4 BP 393 EP 410 AR PII S0022-4073(02)00067-5 PG 18 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 618CV UT WOS:000179401300009 ER PT J AU Devi, VM Benner, DC Smith, MAH Brown, LR Dulick, M AF Devi, VM Benner, DC Smith, MAH Brown, LR Dulick, M TI Multispectrum analysis of pressure broadening and pressure shift coefficients in the (CO2)-C-12-O-16 and (CO2)-C-13-O-16 laser bands SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE CO2; CO2 isotopomers; CO2 laser bands; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; spectral line shape ID FREQUENCY MEASUREMENTS; CO2 LINES; INTENSITIES; PARAMETERS; REGION; CO2-LASER; CONSTANTS AB Extensive high-resolution experimental determination is provided for air- and N-2-broadening and pressure shift coefficients for the two (CO2)-C-13-O-16 laser bands (located at 913.4 and 1017.6 cm(-1), respectively), in addition to new measurements of self-broadening and self-shift coefficients for the (CO2)-C-12-O-16 laser bands. These parameters were determined from analysis of spectra recorded with the McMath-Pierce Fourier transform spectrometer (FTS) of the National Solar Observatory on Kitt Peak, Arizona. We used a multispectrum nonlinear least-squares fitting technique to analyze 30 long path, room temperature absorption spectra. By combining the spectra of (CO2)-C-12 and (CO2)-C-13 in the same fit we were able to obtain a consistent set of line parameters for both molecules. The results obtained for the (CO2)-C-12 and (CO2)-C-13 laser bands were compared with each other, with values in the HITRAN database, and with values reported in the literature for CO2 bands. Comparisons revealed no significant differences in the broadening or shift coefficients between the two laser bands. The coefficients determined for the two isotopomers agreed closely. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Atmospher Sci, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Solar Observ, Natl Opt Astron, Tucson, AZ 85726 USA. RP Devi, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 30 TC 20 Z9 20 U1 0 U2 0 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 1 PY 2003 VL 76 IS 3-4 BP 411 EP 434 AR PII S0022-4073(02)00068-7 PG 24 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 618CV UT WOS:000179401300010 ER PT J AU Carpenter, MH Gottlieb, D Shu, CW AF Carpenter, MH Gottlieb, D Shu, CW TI On the conservation and convergence to weak solutions of global schemes SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article DE conservation laws; conservation; weak solutions; convergence ID FINITE-DIFFERENCE SCHEMES; SPECTRAL VISCOSITY METHOD; LAWS; COMPACT AB In this paper we discuss the issue of conservation and convergence to weak solutions of several global schemes, including the commonly used compact schemes and spectral collocation schemes, for solving hyperbolic conservation laws. It is shown that such schemes, if convergent boundedly almost everywhere, will converge to weak solutions. The results are extensions of the classical Lax-Wendroff theorem concerning conservative schemes. C1 NASA, Langley Res Ctr, CMSB, Hampton, VA 23681 USA. Brown Univ, Div Appl Math, Providence, RI 02912 USA. RP Carpenter, MH (reprint author), NASA, Langley Res Ctr, CMSB, Hampton, VA 23681 USA. RI Shu, Chi-Wang/A-3216-2013 OI Shu, Chi-Wang/0000-0001-7720-9564 NR 21 TC 7 Z9 7 U1 1 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD FEB PY 2003 VL 18 IS 1 BP 111 EP 132 DI 10.1023/A:1020390212806 PG 22 WC Mathematics, Applied SC Mathematics GA 694KN UT WOS:000183773900006 ER PT J AU Figielski, T Morawski, A Wosinski, T Wrotek, S Makosa, A Lusakowska, E Story, T Sipatov, AY Szczerbakow, A Grasza, K Wrobel, J Palosz, W AF Figielski, T Morawski, A Wosinski, T Wrotek, S Makosa, A Lusakowska, E Story, T Sipatov, AY Szczerbakow, A Grasza, K Wrobel, J Palosz, W TI Search for spin filtering by electron tunneling through ferromagnetic EuS barriers in PbS SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT PASPS Conference 2002 CY JUL, 2002 CL WURZBURG, GERMANY SP PASPS DE spin; tunneling; EuS; PbS AB Perpendicular transport through single- and double-barrier heterostructures made up of ferromagnetic EuS layers embedded into a PbS matrix was investigated. Both resonant tunneling and probably spin filtering through EuS barrier were observed. C1 Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. Natl Tech Univ KPI, Kharkov, Ukraine. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Polish Acad Sci, Inst Phys, Al Lotnikow 32-46, PL-02668 Warsaw, Poland. RI Wosinski, Tadeusz/A-2020-2008; Wrobel, Jerzy/G-8042-2014; OI Sipatov, Alexander/0000-0002-2693-2135 NR 9 TC 3 Z9 3 U1 0 U2 2 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD FEB PY 2003 VL 16 IS 1 BP 183 EP 185 DI 10.1023/A:1023290213877 PG 3 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 664KN UT WOS:000182060400045 ER PT J AU Davis, JB Hay, RS Marshall, DB Morgan, PED Sayir, A AF Davis, JB Hay, RS Marshall, DB Morgan, PED Sayir, A TI Influence of interfacial roughness on fiber sliding in oxide composites with La-Monazite Interphases SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID DISSIMILAR ELASTIC-MATERIALS; HIGH-TEMPERATURE STABILITY; MECHANICAL-PROPERTIES; PLASTIC-DEFORMATION; CRACK DEFLECTION; ALUMINA; ABRASION; LAPO4; AL2O3; DISLOCATIONS AB Room-temperature debonding and sliding of fibers coated with La-monazite is assessed using a composite with a polycrystalline alumina matrix and fibers of several different single crystal (mullite and sapphire) and directionally solidified eutectic (Al(2)O(3)/Y(3)Al(5)O(12) and Al(2)O(3)-ZrO(2)) compositions. These fibers provide a range of residual stresses and interfacial roughnesses. Sliding occurred over a debond crack at the fiber-coating interface when the sliding displacement and surface roughness were relatively small. At large sliding displacements with relatively rough interfaces, the monazite coatings were deformed extensively by fracture, dislocations, and occasional twinning, whereas the fibers were undamaged. Dense, fine-grained areas (10 nm grain size) resembling recrystallized microstructures were also observed in the most heavily deformed regions of the coatings. Frictional heating during sliding is assessed. Potential mechanisms for forming such microstructures at low temperature are discussed, and a parallel is drawn with the known resistance of monazite to radiation damage. The ability of La-monazite to undergo both debonding and plastic deformation relatively easily at low temperatures may enable its use as a composite interface. C1 Rockwell Sci, Thousand Oaks, CA 91360 USA. USAF, Res Lab, Mat Directorate, Wright Patterson AFB, OH 45433 USA. Case Western Reserve Univ, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Davis, JB (reprint author), Rockwell Sci, Thousand Oaks, CA 91360 USA. NR 64 TC 30 Z9 30 U1 3 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 2003 VL 86 IS 2 BP 305 EP 316 PG 12 WC Materials Science, Ceramics SC Materials Science GA 644JV UT WOS:000180914900016 ER PT J AU Luo, YL Krueger, SK Mace, GG Xu, KM AF Luo, YL Krueger, SK Mace, GG Xu, KM TI Cirrus cloud properties from a cloud-resolving model simulation compared to cloud radar observations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CUMULUS ENSEMBLE MODEL; ICE-PHASE MICROPHYSICS; MARINE BOUNDARY-LAYER; NUMERICAL-SIMULATION; ATMOSPHERIC RADIATION; MACROSCOPIC BEHAVIOR; CLIMATE MODELS; WATER-CONTENT; PARAMETERIZATION; CIRCULATION AB Cloud radar data collected at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains site were used to evaluate the properties of cirrus clouds that occurred in a cloud-resolving model (CRM) simulation of the 29-day summer 1997 intensive observation period (IOP). The simulation was "forced'' by the large-scale advective temperature and water vapor tendencies, horizontal wind velocity, and turbulent surface fluxes observed at the Southern Great Plains site. The large-scale advective condensate tendency was not observed. The correlation of CRM cirrus amount with Geostationary Operational Environmental Satellite (GOES) high cloud amount was 0.70 for the subperiods during which cirrus formation and decay occurred primarily locally, but only 0.30 for the entire IOP. This suggests that neglecting condensate advection has a detrimental impact on the ability of a model (CRM or single-column model) to properly simulate cirrus cloud occurrence. The occurrence, vertical location, and thickness of cirrus cloud layers, as well as the bulk microphysical properties of thin cirrus cloud layers, were determined from the cloud radar measurements for June, July, and August 1997. The composite characteristics of cirrus clouds derived from this dataset are well suited for evaluating CRMs because of the close correspondence between the timescales and space scales resolved by the cloud radar measurements and by CRMs. The CRM results were sampled at eight grid columns spaced 64 km apart using the same definitions of cirrus and thin cirrus as the cloud radar dataset. The composite characteristics of cirrus clouds obtained from the CRM were then compared to those obtained from the cloud radar. Compared with the cloud radar observations, the CRM cirrus clouds occur at lower heights and with larger physical thicknesses. The ice water paths in the CRM's thin cirrus clouds are similar to those observed. However, the corresponding cloud-layer-mean ice water contents are significantly less than observed due to the CRM's larger cloud-layer thicknesses. The strong dependence of cirrus microphysical properties on layer-mean temperature and layer thickness as revealed by the observations is reproduced by the CRM. In addition, both the CRM and the observations show that the thin cirrus ice water path during large-scale ascent is only slightly greater than during no ascent or descent. C1 Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Luo, YL (reprint author), Univ Utah, Dept Meteorol, 135 S 1460 E,Room 819, Salt Lake City, UT 84112 USA. EM yali@met.utah.edu RI Xu, Kuan-Man/B-7557-2013 OI Xu, Kuan-Man/0000-0001-7851-2629 NR 49 TC 32 Z9 33 U1 1 U2 4 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 2003 VL 60 IS 3 BP 510 EP 525 DI 10.1175/1520-0469(2003)060<0510:CCPFAC>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 634NX UT WOS:000180348000004 ER PT J AU Creekmore, S Seo, JT Yang, Q Wang, Q Anderson, J Pompey, C Temple, D Peng, X Qu, JL Yu, W Wang, A Mott, A Namkung, M Jung, SS Kim, JH AF Creekmore, S Seo, JT Yang, Q Wang, Q Anderson, J Pompey, C Temple, D Peng, X Qu, JL Yu, W Wang, A Mott, A Namkung, M Jung, SS Kim, JH TI Nonlinear optical properties of cadmium telluride semiconductor nanocrystals for optical power-limiting application SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 11th Seoul International Symposium on the Physics of Semiconductors and Applications CY AUG 20-23, 2002 CL SEOUL, SOUTH KOREA SP AIXTRON AG, Epichem Inc, KODENSHI AUK, LG Electr Inst Technol, LUXPIA Co Ltd, Natl Program Tera Level Nanodevices, Thomas Swan Sci Equipment Ltd, Kyung Hee Univ, Adv Display Res Ctr, Sungkyunkwan Univ, Ctr Nanotubes & Nanostruct Composites, Dongguk Univ, Quantum Funct Semiconductor Res Ctr, Chonbuk Natl Univ, Semiconductor Phys Res Ctr DE nanocrystals; nonliner refraction; optical limiting ID SINGLE-BEAM; Z-SCAN; ABSORPTION; ELECTRON; GLASSES; CDTE AB Nonlinear optical properties of cadmium telluride semiconductor nanocrystals were investigated for optical power self-limiting application. The semiconductor nanocrystals were synthesized through colloidal methods. The nonlinear refraction and the nonlinear figure of merit of CdTe nanocrystals in toluene (similar to8 x 10(-5) mol/L) were estimated to be similar to -1 x 10(-13) m(2)/N, and similar to200, respectively. The optical power limiting through CdTe nanoscale materials was mainly by the nonlinear refraction because of the high nonlinear FOM. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Univ Arkansas, Dept Chem & Biochem, Fayetteville, AR 72701 USA. USA, Res Lab, Adelphi, MD 20783 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. Korea Res Inst Stand & Sci, Taejon 305600, South Korea. RP Seo, JT (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. RI Namkung, Min/E-1533-2012 NR 25 TC 12 Z9 12 U1 0 U2 3 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD FEB PY 2003 VL 42 SU S BP S143 EP S148 PG 6 WC Physics, Multidisciplinary SC Physics GA 651TE UT WOS:000181337500009 ER PT J AU Elmustafa, AA Stone, DS AF Elmustafa, AA Stone, DS TI Nanoindentation and the indentation size effect: Kinetics of deformation and strain gradient plasticity SO JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS LA English DT Article DE indentation size effect; activation volume; nanoindentation; strain gradient plasticity; indentation creep; geometrically necessary dislocations; alpha brass; aluminum ID SINGLE-CRYSTALS; HARDNESS; CREEP; INDENTER; METALS; COPPER; DEPTH; MODEL; LAW AB A study of the indentation size effect (ISE) in aluminum and alpha brass is presented. The study employs rate effects to examine the fundamental mechanisms responsible for the ISE. These rate effects are characterized in terms of the rate sensitivity of the hardness, partial derivativeH/partial derivative ln (epsilon)over-dot(eff), where H is the hardness and (epsilon)over-dot(eff) is an effective strain rate in the plastic volume beneath the indenter. partial derivativeH/partial derivative ln (epsilon)over-dot(eff) can be measured using indentation creep, load relaxation, or rate change experiments. The activation volume V*, calculated based on partial derivativeH/partial derivative ln (epsilon)over-dot(eff) which can traditionally be used to compare rate sensitivity data from a hardness test to conventional uniaxial testing, is calculated. Using materials with different stacking fault energy and specimens with different levels of work hardening, we demonstrate how increasing the dislocation density affects V*; these effects may be taken as a kinetic signature of dislocation strengthening mechanisms. We noticed both H and partial derivativeH/partial derivative ln (epsilon)over-dot(eff) (V*) exhibit an ISE. The course of V* vs. H as a result of the ISE is consistent with the course of testing specimens with different level of work hardening. This result was observed in both materials. This suggests that a dislocation mechanism is responsible for the ISE. When the results are fitted to a strain gradient plasticity model, the data at deep indents (microhardness and large nanoindentation) exhibit a straight-line behavior closely identical to literature data. However, for shallow indents (nanoindentation data), the slope of the line severely changes, decreasing by a factor of 10, resulting in a "bilinear behavior". (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, CONITS, Ctr Adv Computat Technol UVA, Hampton, VA 23666 USA. Univ Wisconsin, Madison, WI USA. RP Elmustafa, AA (reprint author), NASA, Langley Res Ctr, CONITS, Ctr Adv Computat Technol UVA, Mail Stop 142, Hampton, VA 23666 USA. RI Stone, Donald/A-7496-2016 NR 42 TC 170 Z9 171 U1 4 U2 69 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-5096 J9 J MECH PHYS SOLIDS JI J. Mech. Phys. Solids PD FEB PY 2003 VL 51 IS 2 BP 357 EP 381 AR PII S0022-5096(02)00033-9 DI 10.1016/S0022-5096(02)00033-9 PG 25 WC Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 629XD UT WOS:000180076800007 ER PT J AU Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L AF Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L TI Whispering-gallery-mode electro-optic modulator and photonic microwave receiver SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID FUSED-SILICA MICROSPHERES; LASER-EMISSION; WAVE RECEIVER; RESONATORS; MICRODROPLETS; RESONANCES; MICROCAVITY; SYSTEMS; CAVITY AB We report on the experimental observation of efficient all-resonant three-wave mixing using high-Q whispering-gallery modes. The modes were excited in a millimeter size toroidal cavity fabricated from LiNbO3. We implemented a low-noise resonant electro-optic modulator based on this wave mixing process. We observe an efficient modulation of light with coherent microwave pumping at 9 GHz with applied power of approximately 10 mW Used as a receiver, the modulator allows us to detect nanowatt microwave radiation. Preliminary results with a 33-GHz modulator prototype are also reported., We present a theoretical interpretation of the experimental results and discuss possible applications of the device. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 37 TC 92 Z9 93 U1 3 U2 23 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD FEB PY 2003 VL 20 IS 2 BP 333 EP 342 DI 10.1364/JOSAB.20.000333 PG 10 WC Optics SC Optics GA 642ZF UT WOS:000180836700009 ER PT J AU Catalina, AV Sen, S Stefanescu, DM AF Catalina, AV Sen, S Stefanescu, DM TI A new analytical approach to predict spacing selection in lamellar and rod eutectic systems SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID FE-C; GROWTH TEMPERATURE; IRREGULAR EUTECTICS; SOLIDIFICATION; ALLOYS; UNDERCOOLINGS; VELOCITY AB The Jackson and Hunt (JH) theory has been modified to relax the assumption of isothermal solid/ liquid interface used in their treatment. Based on the predictions of this modified theory, the traditional definitions of regular and irregular eutectics are revised. For regular eutectics, the new model identifies a range of spacing within the limits defined by the minimum undercooling of the alpha and beta phases. For the irregular Al-Si eutectic system, two different spacing selection mechanisms were identified: (1) for a particular growth rate, a nearly isothermal interface can be achieved at a unique minimum spacing lambda(1); (2) the average spacing (lambda(av) > lambda(1)) is essentially dictated by the undercooling of the faceted phase. Based on the modified theoretical model, a semiempirical expression has been developed to account for the influence of the temperature gradient, which is dominant in the irregular Al-Si system. The behavior of the Fe-Fe3C eutectic is also discussed. The theoretical calculations have been found to be in good agreement with the published experimental measurements. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Solidificat Lab, Tuscaloosa, AL 35487 USA. RP Catalina, AV (reprint author), NASA, George C Marshall Space Flight Ctr, USRA-SD46, Huntsville, AL 35812 USA. RI Stefanescu, Doru/G-8101-2012; OI Stefanescu, Doru M./0000-0001-5544-8396 NR 35 TC 14 Z9 14 U1 0 U2 7 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD FEB PY 2003 VL 34 IS 2 BP 383 EP 394 DI 10.1007/s11661-003-0339-y PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 640GT UT WOS:000180680800019 ER PT J AU Hyers, RW Trapaga, G Abedian, B AF Hyers, RW Trapaga, G Abedian, B TI Laminar-turbulent transition in an electromagnetically levitated droplet SO METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE LA English DT Article ID METAL DROPLETS; MAGNETIC-FIELD; FLOW; OSCILLATIONS; MICROGRAVITY; SPHERE; HEAT AB During experiments on the MSL-1 (first microgravity science laboratory) mission of the space shuttle (STS-83 and STS-94, April and July 1997), a droplet of palladium-silicon alloy was electromagnetically levitated for viscosity measurements. For the nondeforming droplet, the resultant magnetohydrodynamic (MHD) flow inside the drop can be inferred from motion of impurity particulates on the surface. In the experiments, subsequent to melting, Joule heating produces a continuous reduction of viscosity of the fluid resulting in an acceleration of the flow with time. These observations indicate formation of a pair of co-rotating toroidal flow structures inside the spheroidal drop that undergo flow instabilities. As the fluid temperature rises, the amplitude of the secondary flow increases, and beyond a point, the tracers exhibit noncoherent chaotic motion signifying emergence of turbulence inside the drop. Assuming that the observed laminar-turbulent transition is shear-layer type, the internal structure of the toroidal loops is used to develop a semiempirical correlation for the onset of turbulence. Our calculations indicate that the suggested correlation is in modest agreement with the experimental data, with the transition occurring at a Reynolds number of 600. C1 Univ Massachusetts, Dept Mech & Ind Engn, Amherst, MA 01002 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. CINVESTAV, Lab Invest Mat, Unidad Queretaro, Queretaro 76230, Qro, Mexico. Tufts Univ, Dept Mech Engn, Medford, MA 02155 USA. RP Hyers, RW (reprint author), Univ Massachusetts, Dept Mech & Ind Engn, Amherst, MA 01002 USA. RI Hyers, Robert/G-3755-2010; OI Trapaga-Martinez, L. Gerardo/0000-0002-6780-5917 NR 39 TC 22 Z9 22 U1 8 U2 16 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5615 J9 METALL MATER TRANS B JI Metall. Mater. Trans. B-Proc. Metall. Mater. Proc. Sci. PD FEB PY 2003 VL 34 IS 1 BP 29 EP 36 DI 10.1007/s11663-003-0052-7 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 638YK UT WOS:000180600300004 ER PT J AU Chabot, NL Campbell, AJ Jones, JH Humayun, M Agee, CB AF Chabot, NL Campbell, AJ Jones, JH Humayun, M Agee, CB TI An experimental test of Henry's Law in solid metal-liquid metal systems with implications for iron meteorites SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID FE-NI-S; TRACE-ELEMENT FRACTIONATION; SIDEROPHILE ELEMENTS; GROUP IIIAB; IVA IRON; CRYSTALLIZATION; CORE; SOLIDIFICATION; IMMISCIBILITY; BEHAVIOR AB Experimental solid metal-liquid metal partition coefficients have been used to model the crystallization of magmatic iron meteorites and understand the evolution of asteroid cores. However, the majority of the partitioning experiments have been conducted with trace elements doped at levels that are orders of magnitude higher than measured in iron meteorites. Concern about Henry's Law and the unnatural doping levels have been cited as one reason that two recent iron meteorite studies have dismissed the experimental partition coefficients in their modeling. Using laser ablation ICP-MS analysis, this study reports experimentally determined solid metal-liquid metal trace element partition coefficients from runs doped down to the levels occurring in iron meteorites. The analyses for 12 trace elements (As, Co, Cr, Cu, Ga, Ge, Ir, Os, Pd, Pt, Re, and W) show no deviations from Henry's Law, and these results support decades of experimental work in which the partition coefficients were assumed to be independent of trace element concentration. Further, since our experiments are doped with natural levels of trace elements, the partitioning results are directly applicable to iron meteorites and should be used when modeling their crystallization. In contrast, our new Ag data are inconsistent with previous studies, suggesting the high Ag-content in previous studies may have influenced the measured Ag partitioning behavior. C1 Case Western Reserve Univ, Cleveland, OH 44106 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. NASA, Mail Code SR, Houston, TX 77058 USA. Univ New Mexico, Inst Meteorit, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Chabot, NL (reprint author), Case Western Reserve Univ, 112 AW Smith Bldg, Cleveland, OH 44106 USA. RI Chabot, Nancy/F-5384-2015; OI Chabot, Nancy/0000-0001-8628-3176; Humayun, Munir/0000-0001-8516-9435 NR 36 TC 70 Z9 70 U1 2 U2 12 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD FEB PY 2003 VL 38 IS 2 BP 181 EP 196 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 681HT UT WOS:000183031300001 ER PT J AU Nakamura, T Zolensky, M Sekiya, M Okazaki, R Naga, K AF Nakamura, T Zolensky, M Sekiya, M Okazaki, R Naga, K TI Acid-susceptive material as a host phase of argon-rich noble gas in the carbonaceous chondrite Ningqiang SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID METEORITE; SOLAR; COMPONENTS; UREILITE; DIAMONDS; ORIGINS; ALLENDE; HISTORY; RECORD; SHOCK AB A fine-grained dark inclusion in the Ningqiang carbonaceous chondrite consists of relatively pristine solar nebular materials and has high concentrations of heavy primordial rare gases. Trapped Ar-36 concentration amounts to 6 x 10(-6) CC STP/g, which is higher than that of Ningqiang host by a factor of three. Light HF-HCl etching of the dark inclusion removed 86, 73, and 64% of the primordial Ar-36, Kr-84, and Xe-132, respectively. Thus, the majority of the noble gases in this inclusion are located in very acid-susceptive material. Based on the elemental composition, the noble gases lost from the dark inclusion during the acid-treatments are Ar-rich, and the noble gases remaining in the inclusion are Q and HL gases. Transmission electron microscopy showed that the acid treatments removed thin Si, Mg, and Fe-rich amorphous rims present around small olivine and pyroxene grains in the dark inclusion, suggesting that the Ar-rich gases reside in the amorphous layers. A possible origin of the Ar-rich gases is the acquisition of noble-gas ions with a composition fractionated relative to solar abundance favoring the heavy elements by the effect of incomplete ionization under plasma conditions at 8000 K electron temperature. C1 Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan. NASA, Lyndon B Johnson Space Ctr, Mail Code ST, Houston, TX 77058 USA. Univ Tokyo, Grad Sch Sci, Earthquake Chem Lab, Tokyo 1130033, Japan. RP Nakamura, T (reprint author), Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan. NR 31 TC 9 Z9 9 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD FEB PY 2003 VL 38 IS 2 BP 243 EP 250 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 681HT UT WOS:000183031300004 ER PT J AU Tonui, EK Zolensky, ME Lipschutz, ME Wang, MS Nakamura, T AF Tonui, EK Zolensky, ME Lipschutz, ME Wang, MS Nakamura, T TI Yamato 86029: Aqueously altered and thermally metamorphosed CI-like chondrite with unusual textures SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID MARTIAN METEORITE ALH84001; CARBONACEOUS CHONDRITES; TRACE-ELEMENTS; SHOCK METAMORPHISM; PARENT BODY; TAGISH LAKE; MINERALOGY; MATRIX; PHYLLOSILICATES; SIMULATIONS AB We describe the petrologic and trace element characteristics of the Yamato 86029 (Y-86029) meteorite. Y-86029 is a breccia consisting of a variety of clasts, and abundant secondary minerals including coarse- and fine-grained phyllosilicates, Fe-Ni sulfides, carbonates, and magnetite. There are no chondrules, but a few anhydrous olivine-rich grains are present within a very fine-grained phyllosilicate-rich matrix. Analyses of 14 thermally mobile trace elements suggest that Y-86029 experienced moderate, open-system thermal metamorphism. Comparison with data for other heated carbonaceous chondrites suggests metamorphic temperatures of 500-600degreesC for Y-86029. This is apparent petrographically, in partial dehydration of phyllosilicates to incompletely re-crystallized olivine. This transformation appears to proceed through 'intermediate' highly-disordered 'poorly crystalline' phases consisting of newly formed olivine and residual desiccated phyllosilicate and their mixtures. Periclase is also present as a possible heating product of Mg-rich carbonate precursors. Y-86029 shows unusual textures rarely encountered in carbonaceous chondrites. The periclase occurs as unusually large Fe-rich clasts (300-500 mum). Fine-grained carbonates with uniform texture are also present as small (10-15 mum in diameter), rounded to sub-rounded 'shells' of ankerite/siderite enclosing magnetite. These carbonates appear to have formed by low temperature aqueous alteration at specific thermal decomposition temperatures consistent with thermodynamic models of carbonate formation. The fine and uniform texture suggests crystallization from a fluid circulating in interconnected spaces throughout entire growth. One isolated aggregate in Y-86029 also consists of a mosaic of polycrystalline olivine aggregates and sulfide blebs typical of shock-induced melt recrystallization. Except for these unusual textures, the isotopic, petrologic and chemical characteristics of Y86029 are quite similar to those of Y-82162, the only other heated CI-like chondrite known. They were probably derived from similar asteroids rather than one asteroid, and hence may not necessarily be paired. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA, Lyndon B Johnson Space Ctr, ARES, Houston, TX 77058 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Kyushu Univ, Fac Sci, Dept Earth & Planetary Sci, Fukuoka 8128581, Japan. RP Tonui, EK (reprint author), CALTECH, Div Geol & Planetary Sci, Mail Code 170-25, Pasadena, CA 91125 USA. NR 82 TC 27 Z9 27 U1 1 U2 3 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD FEB PY 2003 VL 38 IS 2 BP 269 EP 292 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 681HT UT WOS:000183031300006 ER PT J AU Zolensky, M Nakamura, K Weisberg, MK Prinz, M Nakamura, T Ohsumi, K Saitow, A Mukai, M Gounelle, M AF Zolensky, M Nakamura, K Weisberg, MK Prinz, M Nakamura, T Ohsumi, K Saitow, A Mukai, M Gounelle, M TI A primitive dark inclusion with radiation-damaged silicates in the Ningqiang carbonaceous chondrite SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID ION-BEAM IRRADIATION; REFRACTORY INCLUSIONS; RICH INCLUSIONS; CV3 CHONDRITES; SOLAR NEBULA; OLIVINE; ALLENDE; COMPONENTS; ORIGIN; PHASE AB A petrologic and TEM study of a remarkable dark inclusion (DI) in the Ningqiang CV3 chondrite reveals that it is a mixture of highly primitive solar nebula materials. The DI contains two lithologies. The first, lithology A, contains micron-sized olivine and pyroxene grains rimmed by amorphous materials with compositions similar to the underlying crystalline grains. The second, lithology B, appears to preserve the mineralogy of lithology A before formation of the amorphous rims. Overall, the Ningqiang DI appears to record the following processes: 1) formation (condensation and Fe-enrichment) of olivine crystals in the nebula with compositions of Fo(42-62); 2) irradiation, resulting in amorphitization of the olivine and pyroxene to varying degrees; 3) partial annealing, resulting in formation of fairly large, euhedral olivine and pyroxene grains with remnant amorphous sharply-bounded rims; 4) in some cases, prolonged annealing, resulting in the formation of microcrystalline olivine or pyroxene rims. The latter annealing would have been a natural consequence of irradiation near the critical temperature for olivine; and 5) mixture of the above materials (lithology A) with nebular condensate high-Ca pyroxene and olivine, which escaped nebular processing, to become lithology B. We suggest that the amorphous rims in lithology A formed in an energetic solar event such as a bi-polar outflow or FU-orionis flare. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. CUNY, Kingsborough Coll, Dept Phys Sci, New York, NY 11235 USA. Amer Museum Nat Hist, Dept Earth & Planetary Sci, New York, NY 10024 USA. Kyushu Univ, Fac Sci, Fukuoka 8120053, Japan. Inst Mat Struct Sci, KEK, High Energy Accelerator Res Org, Photon Factory, Tsukuba, Ibaraki 305, Japan. Univ Paris 11, CSNSM, F-91405 Orsay, France. RP Zolensky, M (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 45 TC 15 Z9 15 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD FEB PY 2003 VL 38 IS 2 BP 305 EP 322 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 681HT UT WOS:000183031300008 ER PT J AU Cooper, SM Chuang, HF Cinke, M Cruden, BA Meyyappan, M AF Cooper, SM Chuang, HF Cinke, M Cruden, BA Meyyappan, M TI Gas permeability of a buckypaper membrane SO NANO LETTERS LA English DT Article ID CARBON NANOTUBES AB Gas permeability has been measured through a carbon nanotube-based "buckypaper" membrane and through commercially available porous anodized alumina membranes with 200 nm nominal pore dimensions. Permeation relationships through the alumina membrane are consistent with Knudsen-type diffusion. Permeation behavior in the "buckypaper" membrane, however, shows a strong dependence of permeability on pressure that is not explained by typical transport mechanisms. It is suggested that elastic deformation of the membrane from the pressure differential may contribute to this behavior. C1 NASA, Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Cruden, BA (reprint author), NASA, Ames Ctr Nanotechnol, Moffett Field, CA 94035 USA. NR 12 TC 81 Z9 82 U1 2 U2 36 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 2003 VL 3 IS 2 BP 189 EP 192 DI 10.1021/nl0259131 PG 4 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 645VW UT WOS:000181001500017 ER PT J AU Vander Wal, RL Tomasek, AJ Ticich, TM AF Vander Wal, RL Tomasek, AJ Ticich, TM TI Synthesis, laser processing, and flame purification of nanostructured carbon SO NANO LETTERS LA English DT Article ID VAPORIZATION; NANOTUBES; POWDERS; LITHIUM; SOOT AB Initial results are presented here for laser-induced restructuring of nanospheric carbon. Laser fluence is used to control the degree of restructuring. A flame-based oxidation process treats the post-annealed carbon as an aerosol stream to remove unconverted carbon and residual carbon generated at higher laser fluences. The initial carbon nanostructure is shown to direct the annealing process and resulting carbon "nanoorganization" at the atomic level. C1 NASA Glenn, NCMR, Cleveland, OH 44135 USA. Centenary Coll Louisiana, Dept Chem, Shreveport, LA 71104 USA. RP Vander Wal, RL (reprint author), NASA Glenn, NCMR, MS 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 36 TC 23 Z9 24 U1 0 U2 8 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 2003 VL 3 IS 2 BP 223 EP 229 DI 10.1021/nl020232r 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 645VW UT WOS:000181001500024 ER PT J AU Cartoixa, X Ting, DZY McGill, TC AF Cartoixa, X Ting, DZY McGill, TC TI An efficient multiband envelope function approximation method for spintronics SO NANOTECHNOLOGY LA English DT Article; Proceedings Paper CT 3rd International Conference on Trends in Nanotechnology CY SEP 09-13, 2002 CL SANTIAGO COMPOSTE, SPAIN SP Univ Autonoma Madrid, Consejo Superior Investigaciones Cient, CMP Cient, Univ Cambridge, Univ Purdue, Univ Complutense Madrid, Univ Carlos III Madrid, Univ Santiago Compostela ID LATTICE BAND-STRUCTURE; GASB QUANTUM-WELLS; SEMICONDUCTOR HETEROSTRUCTURES; THEORETICAL INVESTIGATIONS; ELECTRON SUBBAND; LIGHT-HOLE; SPIN; STATES; DIODE AB We have developed an eight-band finite-difference envelope function approximation model capable of reproducing in almost all situations the true D-2d or C-2v symmetry of [001] grown zinc-blende heterostructures. We have used our model to study the relative contributions of the bulk inversion asymmetry (BIA) and structural inversion asymmetry to the spin splitting in the conduction band of asymmetric AlSb/GaSb/InAs/AlSb quantum wells, and clarify apparently contradictory statements about the relative magnitude of the two contributions. We show that, in the system under study, the inclusion of BIA effects changes considerably the angular dependence and the magnitude of the splitting. We also investigate how BIA changes the transmission properties of a resonant tunnelling structure. C1 CALTECH, TJ Watson Sr Labs Appl Phys 128 95, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McGill, TC (reprint author), CALTECH, TJ Watson Sr Labs Appl Phys 128 95, Pasadena, CA 91125 USA. NR 43 TC 3 Z9 3 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD FEB PY 2003 VL 14 IS 2 BP 308 EP 311 AR PII S0957-4484(03)54372-0 DI 10.1088/0957-4484/14/2/340 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 656TG UT WOS:000181624100041 ER PT J AU Adamovsky, G Lekki, J Lock, JA AF Adamovsky, G Lekki, J Lock, JA TI Detection sensitivity optimization of optical signals generated by fiber optic Bragg gratings under dynamic excitation SO OPTICAL ENGINEERING LA English DT Article DE Bragg gratings; fiber optics; optical sensors; wavelength detection; unbalanced interferometers ID SENSORS; SYSTEM AB The dynamic response of a fiber optic Bragg grating to mechanical vibrations is examined both theoretically and experimentally. The theoretical expressions describing the consequences of changes in the grating's reflection spectrum are derived for partially coherent beams in an interferometer. The analysis is given in terms of the dominant wavelength, optical bandwidth, and optical path difference of the interfering signals. Changes in the reflection spectrum caused by a periodic stretching and compression of the grating are experimentally measured using an unbalanced Michelson interferometer, a Michelson interferometer with a nonzero optical path difference. The interferometer's sensitivity to changes in the dominant wavelength of the interfering beams is measured as a function of interferometer unbalance and is compared to theoretical predictions. The theoretical analysis enables the user to determine the optimum performance for an unbalanced interferometer. (C) 2003 Society of Photo-Optical Instrumentation Engineers. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. Cleveland State Univ, Dept Phys, Cleveland, OH 44115 USA. RP Adamovsky, G (reprint author), NASA, Glenn Res Ctr Lewis Field, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD FEB PY 2003 VL 42 IS 2 BP 425 EP 430 DI 10.1117/1.1534593 PG 6 WC Optics SC Optics GA 655BM UT WOS:000181531500019 ER PT J AU Klaasen, KP Breneman, HH Simon-Miller, AA Banfield, D Levanas, GC AF Klaasen, KP Breneman, HH Simon-Miller, AA Banfield, D Levanas, GC TI Operations and calibration of the solid-state imaging system during the Galileo extended mission at Jupiter SO OPTICAL ENGINEERING LA English DT Article DE charge-coupled device camera; calibration; digital imaging; remote sensing; space instrumentation; astronomy ID JOVIAN PLANETS; SPECTROPHOTOMETRY; PERFORMANCE; METHANE; CAMERA; TITAN AB The solid state imaging (SSI) subsystem on the National Aeronautics and Space Administration's (NASA's) Galileo spacecraft has successfully completed a 4-yr extended mission exploring the Jovian system. The SSI remained in stable calibration throughout its total 12-yr flight time and returned valuable scientific data until the end of the mission. A slight loss in spatial resolution occurred between the last primary-mission calibration and that done during the extended mission. The absolute spectral radiometric calibration has been determined to 5 to 7% accuracy across the camera's eight spectral filters. A possible shift in the central wavelength of one of the methane-absorption-band filters of similar to3 nm shortward may have occurred late in the extended mission. The charge-coupled device (CCD) detector endured the harsh radiation environment at Jupiter to a total dose of similar to4 krad without any serious permanent damage. Some radiation-induced problems in the detector clocking and signal-chain electronics rendered the 2-X2-pixel summation modes unusable and required that the CCD light flood and erasure prior to each exposure be disabled. However, good-quality imaging continued to be possible even in the most extreme radiation fluxes encountered. The successful return of 1453 images during the extended mission nearly matched the number of frames returned during the primary mission. (C) 2003 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Cornell Univ, Ithaca, NY 14853 USA. RP Klaasen, KP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 230-260, Pasadena, CA 91109 USA. RI Simon, Amy/C-8020-2012; OI Simon, Amy/0000-0003-4641-6186; Banfield, Don/0000-0003-2664-0164 NR 15 TC 5 Z9 5 U1 0 U2 3 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD FEB PY 2003 VL 42 IS 2 BP 494 EP 509 DI 10.1117/1.1534590 PG 16 WC Optics SC Optics GA 655BM UT WOS:000181531500029 ER PT J AU Shan, HZ Singh, JP Oliker, L Biswas, R AF Shan, HZ Singh, JP Oliker, L Biswas, R TI Message passing and shared address space parallelism on an SMP cluster SO PARALLEL COMPUTING LA English DT Article DE PC cluster; message passing; distributed shared memory; benchmark applications; parallel performance ID PROGRAMMING PARADIGMS; ALGORITHM; MODELS AB Currently, message passing (MP) and shared address space (SAS) are the two leading parallel programming paradigms. MP has been standardized with MPI, and is the more common and mature approach; however, code development can be extremely difficult, especially for irregularly structured computations. SAS offers substantial ease of programming, but may suffer from performance limitations due to poor spatial locality and high protocol overhead. In this paper, we compare the performance of and the programming effort required for six applications under both programming models on a 32-processor PC-SMP cluster, a platform that is becoming increasingly attractive for high-end scientific computing. Our application suite consists of codes that typically do not exhibit scalable performance under shared-memory programming due to their high communication-to-computation ratios and/or complex communication patterns. Results indicate that SAS can achieve about half the parallel efficiency of MPI for most of our applications, while being competitive for the others. A hybrid MPI + SAS strategy shows only a small performance advantage over pure MPI in some cases. Finally, improved implementations of two MPI collective operations on PC-SMP clusters are presented. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Adv Supercomp NAS Div, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. Princeton Univ, Dept Comp Sci, Princeton, NJ 08544 USA. RP NASA, Ames Res Ctr, Adv Supercomp NAS Div, Mail Stop T27A-1, Moffett Field, CA 94035 USA. EM hshan@lbl.gov; jps@cs.princeton.edu; loliker@lbl.gov; rbiswas@nas.nasa.gov NR 24 TC 21 Z9 22 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8191 EI 1872-7336 J9 PARALLEL COMPUT JI Parallel Comput. PD FEB PY 2003 VL 29 IS 2 BP 167 EP 186 AR PII S0167-8191(02)00222-3 DI 10.1016/S0167-8191(02)00222-3 PG 20 WC Computer Science, Theory & Methods SC Computer Science GA 645EX UT WOS:000180964200001 ER PT J AU Lallemand, P d'Humieres, D Luo, LS Rubinstein, R AF Lallemand, P d'Humieres, D Luo, LS Rubinstein, R TI Theory of the lattice Boltzmann method: Three-dimensional model for linear viscoelastic fluids SO PHYSICAL REVIEW E LA English DT Article ID NAVIER-STOKES EQUATION; GAS AUTOMATA; FLOWS AB A three-dimensional lattice Boltzmann model with thirty two discrete velocity distribution functions for viscoelastic fluid is presented in this work. The model is based upon the generalized lattice Boltzmann equation constructed in moment space. The nonlinear equilibria of the model have a number of coupling constants that are free parameters. The dispersion equation of the model is analyzed under various conditions to obtain the constraints on the free parameters such that the model satisfies isotropy and Galilean invariance. The macroscopic equations are also derived from the lattice Boltzmann model through the dispersion equation analysis and the Chapman-Enskog analysis. We demonstrate that the dispersion equation analysis can be used as a general and effective means to derive hydrodynamic equations, excluding some nonlinear source terms, from the lattice Boltzmann model, to obtain conditions for its isotropy and Galilean invariance, and to optimize its stability. We show that the hydrodynamic behavior of the lattice Boltzmann model has memory effects, and that in the linear regime, it behaves as a viscoelastic fluid described by the Jeffreys model. Some numerical results to verify the theoretical analysis of the model are also presented. C1 Univ Paris 11, Lab CNRS ASCI, F-91405 Orsay, France. Ecole Normale Super, Lab Phys Stat, F-75321 Paris 05, France. NASA, ICASE, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Computat Modeling & Simulat Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP Lallemand, P (reprint author), Univ Paris 11, Lab CNRS ASCI, Batiment 506, F-91405 Orsay, France. EM lalleman@asci.fr; domimq.dhumieres@lps.ens.fr; luo@NIAnet.org; r.rubinstein@larc.nasa.gov RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 28 TC 34 Z9 34 U1 3 U2 12 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2003 VL 67 IS 2 AR 021203 DI 10.1103/PhysRevE.67.021203 PN 1 PG 19 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 654WP UT WOS:000181520200020 PM 12636662 ER PT J AU Zhong, F Barmatz, M Hahn, I AF Zhong, F Barmatz, M Hahn, I TI Application of minimal subtraction renormalization to crossover behavior near the He-3 liquid-vapor critical point SO PHYSICAL REVIEW E LA English DT Article ID EPSILON-EXPANSION; 3 DIMENSIONS; AMPLITUDE FUNCTIONS; HE-3-HE-4 MIXTURES; CRITICAL EXPONENTS; FIELD-THEORY; HEAT; SUSCEPTIBILITY; EQUATION; FLUIDS AB Parametric expressions are used to calculate the isothermal susceptibility, specific heat, order parameter, and correlation length along the critical isochore and coexistence curve from the asymptotic region to crossover region. These expressions are based on the minimal-subtraction renormalization scheme within the phi(4) model. Using two adjustable parameters in these expressions, we fit the theory globally to recently obtained experimental measurements of isothermal susceptibility and specific heat along the critical isochore and coexistence curve, and early measurements of coexistence curve and light scattering intensity along the critical isochore of He-3 near its liquid-vapor critical point. The theory provides good agreement with these experimental measurements within the reduced temperature range \t\less than or equal to2x10(-2). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zhong, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 16 Z9 16 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD FEB PY 2003 VL 67 IS 2 AR 021106 DI 10.1103/PhysRevE.67.021106 PN 1 PG 20 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 654WP UT WOS:000181520200010 ER PT J AU Vassiliadis, D Weigel, RS Klimas, AJ Kanekal, SG Mewaldt, RA AF Vassiliadis, D Weigel, RS Klimas, AJ Kanekal, SG Mewaldt, RA TI Modes of energy transfer from the solar wind to the inner magnetosphere SO PHYSICS OF PLASMAS LA English DT Article ID GEOSYNCHRONOUS ORBIT; RADIATION BELT; RELATIVISTIC ELECTRONS; SPACE WEATHER; PREDICTION; PARTICLES; SAMPEX; STORMS; CUSP AB Energy transport from the interplanetary plasma to Earth's inner magnetosphere occurs in a range of time scales and efficiencies. It is often hypothesized that this range is smoothly varying with radial geocentric distance, indicating the transport involves many processes, whose ranges overlap. Here we report evidence from observations, and time series analysis, and other data-based modeling which indicates that the coupling of magnetospheric relativistic electron fluxes to solar wind variables occurs in specific ranges of radial distance (L shell). These findings probably have important consequences for the understanding of physical mechanisms responsible for the acceleration in each region. We identify three distinct regions: P-0 at approximately 37 R-E. Each one responds to a different combination of solar wind variables, and couples to the main driver variable, the solar wind speed V-SW, in a different way. Mode P-1 is the prototypical response of the inner magnetosphere. The electron flux responds more slowly than the other two regions to V-SW (2-3 days): high-speed streams are the most geoeffective structures for that region. Mode P-0 responds significantly faster (<1 day) and seems to be more affected by the negative B-z component of the interplanetary field (probably through magnetic reconnection) and the magnitude of the field, rather than by variations in solar wind plasma variables. Region P-2 contains much lower fluxes of trapped particles than the other two, and responds rapidly (similar to1 day) to positive B-z and to lower solar wind speed. The interpretation is that these regions are representative of different modes of energy transfer from the interplanetary medium to the inner magnetosphere with implications for very different particle acceleration mechanisms. (C) 2003 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Natl Res Council, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Colorado, Lab Astrophys & Space Phys, Boulder, CO 80309 USA. CALTECH, Pasadena, CA 91125 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. NR 31 TC 11 Z9 11 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 2003 VL 10 IS 2 BP 463 EP 473 DI 10.1063/1.1535938 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 636JA UT WOS:000180450000020 ER PT J AU Atreya, SK Mahaffy, PR Niemann, HB Wong, MH Owen, TC AF Atreya, SK Mahaffy, PR Niemann, HB Wong, MH Owen, TC TI Composition and origin of the atmosphere of Jupiter - an update, and implications for the extrasolar giant planets SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Meeting of the European-Geophysical-Society CY MAR, 2001 CL NICE, FRANCE SP European Geophys Soc ID PROBE MASS-SPECTROMETER; ISO-SWS OBSERVATIONS; SOLAR; SATURN; NITROGEN; ABUNDANCE; DEUTERIUM; REGOLITH; PROFILE; CLOUD AB New developments have led to this update of the composition and origin of Jupiter's atmosphere that were originally discussed in our Planet. Space Sci. 47 (1999) 1243 paper. Since Jupiter can provide important insight into the atmospheres of extrasolar giant planets (EGP), we also discuss here the possible implications of the first detection of an atmosphere on an EGP. The ammonia mixing ratio on Jupiter has now been determined directly from the Galileo probe mass spectrometer (GPMS) data, and its value relative to H-2 (7.1 +/- 3.2) x 10(-4) in the 9-12 bar region, is found to be similar to the previously reported result inferred from the radio attenuation technique on Galileo. The Jovian N-15/N-14 ratio is found to be much lower than the terrestrial value at (2.3 +/- 0.3) x 10(-3). A complete analysis of the various uncertainties in the GPMS data yields an H2O mixing ratio of 6.0(+3.9,-2.8) x 10(-4) at 19 bar in the hotspot, and a trend of increase with depth; all other mixing ratios and error bars remain unchanged. CH3, previously detected on Saturn and Neptune, has now also been detected in the atmosphere of Jupiter recently by Cassini. Benzene is the heaviest hydrocarbon detected to date in the atmospheres of Jupiter and Saturn. Abundances inferred from Infrared Space Observatory measurements are 9(+4.5,-7.5) x 10(14) and 4.7(+2.1, -1.1) X 10(13) cm(-2) for pressures less than 50 and 10 mbar on Jupiter and Saturn, respectively. Finally, we propose that the recently detected sodium in the atmosphere of the EGP orbiting HD 209458 may have mainly a post-accretionary extraplanetary origin, rather than being primordial. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Atreya, SK (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RI Mahaffy, Paul/E-4609-2012 NR 42 TC 94 Z9 94 U1 1 U2 8 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 2003 VL 51 IS 2 BP 105 EP 112 AR PII S0032-0633(02)00144-7 DI 10.1016/S0032-0633(02)00144-7 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 651WN UT WOS:000181345300003 ER PT J AU Samuelson, RE AF Samuelson, RE TI Titan's atmospheric engine: an overview SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Meeting of the European-Geophysical-Society CY MAR, 2001 CL NICE, FRANCE SP European Geophys Soc DE titan; engine; atmosphere; overview ID VOYAGER INFRARED OBSERVATIONS; SEASONAL CHANGE; MODEL; STRATOSPHERE; TROPOSPHERE; SATURN; CLOUDS; PHOTOCHEMISTRY; TEMPERATURE; OCCULTATION AB Heating occurs in Titan's stratosphere from the absorption of incident solar radiation by methane and aerosols. About 10% of the incident sunlight reaches Titan's surface and causes beating there. Thermal radiation redistributes heat within the atmosphere and cools to space. The resulting vertical temperature profile is stable against convection and a state of radiative equilibrium is established. Equating theoretical and observed temperature profiles enables an empirical determination of the vertical distribution of thermal opacity. A uniformly mixed aerosol is responsible for most of the opacity in the stratosphere, whereas collision-induced absorption of gases is the main contributor in the troposphere. Occasional clouds are observed in the troposphere in spite of the large degrees of methane supersaturation found there. Photochemistry converts CH4 and N-2 into more complex hydrocarbons and nitriles in the stratosphere and above. Thin ice clouds of trace organics are formed in the winter and early spring polar regions of the lower stratosphere. Precipitating ice particles serve as condensation sites for supersaturated methane vapor in the troposphere below, resulting in lowered methane degrees of supersaturation in the polar regions. Latitudinal variations of stratospheric temperature are seasonal, and lag instantaneous response to solar irradiation by about one season for two reasons: (1) an actual instantaneous thermal response to a latitudinal distribution of absorbing gases, themselves out of phase with the sun by about one season, and (2) a sluggish dynamical response of the stratosphere to the latitudinal transport of angular momentum, induced by radiative heating and cooling. Mean vertical abundances of stratospheric organics and aerosols are determined primarily by atmospheric chemistry and condensation, whereas latitudinal distributions are more influenced by meridional circulations. In addition to preferential scavenging by precipitating ice particles from above, the polar depletion of supersaturated methane results from periodic scavenging by short-lived tropospheric clouds, coupled with the steady poleward march of the continuously drying atmosphere due to meridional transport. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Samuelson, RE (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. NR 57 TC 9 Z9 9 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 2003 VL 51 IS 2 BP 127 EP 145 AR PII S0032-0633(02)00143-5 DI 10.1016/S0032-0633(02)00143-5 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 651WN UT WOS:000181345300005 ER PT J AU Pawlowski, KJ Belvin, HL Raney, DL Su, J Harrison, JS Siochi, EJ AF Pawlowski, KJ Belvin, HL Raney, DL Su, J Harrison, JS Siochi, EJ TI Electrospinning of a micro-air vehicle wing skin SO POLYMER LA English DT Article DE electrospinning; electroactive polymers; micro-air vehicle ID ELECTRICALLY FORCED JETS; NANOFIBERS; POLYMERS; FIBERS; MORPHOLOGY AB Electrospinning was utilized to create lightweight, electrically responsive wing skins for micro-air vehicle (MAV) wing frame designs. Various compositions of an electroactive polymer were investigated to determine the appropriate electrospinning conditions for these materials. Electrospun mats of these materials were characterized via optical microscopy and scanning electron microscopy. Tensile properties of the electrospun fibers were also measured. An optimal polymer composition was electrospun onto MAV wing frames to create a bird wing-like texture. Preliminary testing of electroactivity of these prototype MAV wings is reported here. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Pawlowski, KJ (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 35 TC 63 Z9 69 U1 0 U2 14 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD FEB PY 2003 VL 44 IS 4 BP 1309 EP 1314 AR PII S0032-3861(02)00859-5 DI 10.1016/S0032-3861(02)00859-5 PG 6 WC Polymer Science SC Polymer Science GA 638TA UT WOS:000180585400044 ER PT J AU Brentner, KS Farassat, F AF Brentner, KS Farassat, F TI Modeling aerodynamically generated sound of helicopter rotors SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review ID WILLIAMS-HAWKINGS EQUATION; VORTEX INTERACTION NOISE; SPEED IMPULSIVE NOISE; TRAILING-EDGE NOISE; LOW MACH NUMBERS; ACOUSTIC SCATTERING; QUADRUPOLE NOISE; 3-DIMENSIONAL BODIES; ROBUST METHOD; PREDICTION AB A great deal of progress has been made in the modeling of aerodynamically generated sound of rotors over the past decade. Although the modeling effort has focused on helicopter main rotors, the theory is generally valid for a wide range of rotor configurations. The Ffowcs Williams-Hawkings (FW-H) equation has been the foundation for much of the development. The monopole and dipole source terms of the FW-H equation account for the thickness and loading noise, respectively. Blade-vortex-interaction noise and broadband noise are important types of loading noise, hence much research has been directed toward the accurate modeling of these noise mechanisms. Both subsonic and supersonic quadrupole noise formulations have been developed for the prediction of high-speed impulsive noise. In an effort to eliminate the need to compute the quadrupole contribution, the FW-H equation has also been utilized on permeable surfaces surrounding all physical noise sources. Comparisons of the Kirchhoff formulation for moving surfaces with the FW-H equation have shown that the Kirchhoff formulation for moving surfaces can give erroneous results for aeroacoustic problems. Finally, significant progress has been made incorporating the rotor noise models into full vehicle noise prediction tools. Published by Elsevier Science Ltd. C1 Penn State Univ, Dept Aerosp Engn, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Aeroacoust Branch, Hampton, VA 23681 USA. RP Brentner, KS (reprint author), Penn State Univ, Dept Aerosp Engn, University Pk, PA 16802 USA. EM ksbrentner@psu.edu NR 117 TC 81 Z9 84 U1 1 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0376-0421 J9 PROG AEROSP SCI JI Prog. Aeosp. Sci. PD FEB-APR PY 2003 VL 39 IS 2-3 BP 83 EP 120 DI 10.1016/S0376-0421(02)00068-4 PG 38 WC Engineering, Aerospace SC Engineering GA 661VE UT WOS:000181909900001 ER PT J AU Hazeltine, E Diedrichsen, J Kennerley, SW Ivry, RB AF Hazeltine, E Diedrichsen, J Kennerley, SW Ivry, RB TI Bimanual cross-talk during reaching movements is primarily related to response selection, not the specification of motor parameters SO PSYCHOLOGICAL RESEARCH-PSYCHOLOGISCHE FORSCHUNG LA English DT Article ID OVERLAPPING-TASK-PERFORMANCE; DUAL-TASK; MEMORY RETRIEVAL; COMPATIBILITY; INTERFERENCE; STIMULUS; COORDINATION; CALLOSOTOMY; AMPLITUDES; MODEL AB Simultaneous reaching movements made with the two hands can show a considerable increase in reaction time (RT) when they differ in terms of direction or extent, compared to when the movements involve the same direction and extent. This cost has been attributed to cross-talk in the specification of the motor parameters for the two hands. However, a recent study [Diedrich-sen, Hazeltine, Kennerley, & Ivry, (2001). Psychological Science, 12, 493-498] indicates that when reaching movements are cued by the onset of the target endpoint, no compatibility effects are observed. To determine why directly cued movements are immune from interference, we varied the stimulus onset asynchrony for the two movements and used different combinations of directly cued and symbolically cued movements. In two experiments, compatibility effects were only observed when both movements were symbolically cued. No difference was found between compatible and incompatible movements when both movements were directly cued or when one was directly cued and the other was symbolically cued. These results indicate that interference is not related to the specification of movement parameters but instead emerges from processes associated with response selection. Moreover, the data suggest that cross-talk, when present, primarily shortens the RT of the second movement on compatible trials rather than lengthening this RT on incompatible trials. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA. RP Hazeltine, E (reprint author), NASA, Ames Res Ctr, Mail Stop 262-4, Moffett Field, CA 94035 USA. RI Diedrichsen, Jorn/A-7789-2010 OI Diedrichsen, Jorn/0000-0003-0264-8532 NR 41 TC 42 Z9 42 U1 2 U2 6 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0340-0727 J9 PSYCHOL RES-PSYCH FO JI Psychol. Res.-Psychol. Forsch. PD FEB PY 2003 VL 67 IS 1 BP 56 EP 70 DI 10.1007/s00426-002-0119-0 PG 15 WC Psychology, Experimental SC Psychology GA 657AT UT WOS:000181643800006 PM 12589450 ER PT J AU Malumuth, EM Hill, RS Gull, T Woodgate, BE Bowers, CW Kimble, RA Lindler, D Plait, P Blouke, M AF Malumuth, EM Hill, RS Gull, T Woodgate, BE Bowers, CW Kimble, RA Lindler, D Plait, P Blouke, M TI Removing the fringes from Space Telescope Imaging Spectrograph slitless spectra SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID LIBRARY AB Using what is known about the physical and chemical structure of the CCD detector on the Space Telescope Imaging Spectrograph (STIS) and over 50 calibration images taken with different wavelength mappings onto the detector, we have devised a model function that allows us to predict the fringing of any spectral image taken with the STIS CCD. This function is especially useful for spectra taken without a slit with the G750L grating. The STIS parallel observing program uses this "slitless spectroscopy" mode extensively. The arbitrary mapping of wavelength versus position that results from each source's chance position in the field renders direct calibration of the fringe amplitudes in this mode impossible. However, we find that correcting observed data using our semiempirical fringing model produces a substantial reduction in the fringe amplitudes. Tests using the flux calibration white dwarf standard G191-B2B show that we can reduce the fringe amplitude in the 9000-10000 Angstrom region from about 20% peak to peak (10% rms) to about 4% peak to peak (2% rms) using the model, while a standard calibration using a "fringe flat" reduces the fringe amplitudes to 3.3% peak to peak (1.7% rms). The same technique is applicable to other astronomical CCDs. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Raytheon ITSS Corp, Lanham, MD 20706 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Adv Comp Concepts, Potomac, MD 20854 USA. Sigma Space Corp, Lanham, MD 20706 USA. Sonoma State Univ, Dept Phys & Astron, Rohnert Pk, CA 94928 USA. Sci Imaging Technol Inc, Tigard, OR 97223 USA. RP Malumuth, EM (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Woodgate, Bruce/D-2970-2012; Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 9 TC 9 Z9 10 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD FEB PY 2003 VL 115 IS 804 BP 218 EP 234 DI 10.1086/345913 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 636LX UT WOS:000180458400007 ER PT J AU Hooper, DM Bursik, MI Webb, FH AF Hooper, DM Bursik, MI Webb, FH TI Application of high-resolution, interferometric DEMs to geomorphic studies of fault scarps, Fish Lake Valley, Nevada-California, USA SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SEGMENTATION; RADAR; MONTANA; HISTORY; ZONES; BASIN; LIDAR; AGES AB Recent developments in interferometric radar remote sensing provide a method for deriving detailed topographic and slope information for fault-scarp detection. In October 1996, the airborne TOPSAR instrument [IEEE Trans. Geosci. Remote Sens., 30 (1992) 933] was flown over southwest Nevada and east-central California. Topography calculated from TOPSAR data are in the form of a high-resolution (5-mi spatial grid) digital elevation model (DEM). In this study, we focus upon the large, steep fault scarps that cut alluvium and alluvial fans, in Fish Lake Valley, east of the White Mountains of Nevada- California. A series of topographic profiles extracted from the DEM reveal that the larger fault scarps are greater than 40 in in height and that the average midsection slope angle for all measured scarps is approximately 23degrees. These large scarps are the product of multiple offsets rather than a single event. Other relevant geomorphic features present in the digital topography include splays and benches along the main fault, levees, cutbanks, gullies incising fault scarp slopes, shutterridges, offset drainage, and small normal faults with scarp heights of only 4-6 m. Field work corroborated general geomorphologic landforms, confirmed fault-scarp morphometry, and aided the evaluation of the accuracy of the DEM. We are also able to assess fault segmentation models that divide the Fish Lake Valley fault zone (FLVFZ) into discrete segments based upon surface-rupture characteristics. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Youngstown State Univ, Dept Geol & Environm Sci, Youngstown, OH 44555 USA. SUNY Buffalo, Dept Geol, Buffalo, NY 14260 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hooper, DM (reprint author), Youngstown State Univ, Dept Geol & Environm Sci, 1 Univ Plaza, Youngstown, OH 44555 USA. EM dmhooper@ysu.edu RI Namikawa, Laercio/C-5559-2013 OI Namikawa, Laercio/0000-0001-7847-1804 NR 22 TC 27 Z9 31 U1 0 U2 7 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 FEB PY 2003 VL 84 IS 2 BP 255 EP 267 AR PII S0034-4257(02)00110-4 DI 10.1016/S0034-4257(02)00110-4 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 673RA UT WOS:000182592900008 ER PT J AU Hodgson, ME Jensen, JR Schmidt, L Schill, S Davis, B AF Hodgson, ME Jensen, JR Schmidt, L Schill, S Davis, B TI An evaluation of LIDAR- and IFSAR-derived digital elevation models in leaf-on conditions with USGS Level 1 and Level 2 DEMs SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE LIDAR; IFSAR; DEM; elevation accuracy ID ACCURACY AB An assessment of four different remote sensing based methods for deriving digital elevation models (DEMs) was conducted in a flood-prone watershed in North Carolina. New airborne LIDAR (light detecting and ranging) and IFSAR (interferometric synthetic aperture radar (SAR)) data were collected and corresponding DEMs created. These new sources were compared to two methods: Gestalt Photomapper (GPM) and contour-to-grid, used by the U.S. Geological Survey (USGS) for creating DEMs. Survey-grade points (1470) for five different land cover classes were used as reference points. One unique aspect of this study was the LIDAR and IFSAR data were collected during leaf-on conditions. Analyses of absolute elevation accuracy and terrain slope were conducted. The LIDAR- and contour-to-grid derived DEMs exhibited the highest overall absolute elevation accuracies. Elevation accuracy was found to vary with land cover categories. Elevation accuracy also decreased with increasing slopes-but only for the scrub/shrub land cover category. Appreciable terrain slope errors for the reference points were found with all methods. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ S Carolina, Dept Geog, Columbia, SC 29208 USA. Baruch Marine Sci Lab, Georgetown, SC 29585 USA. GeoMetr Inc, Columbia, SC 29210 USA. NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, MS 39529 USA. RP Hodgson, ME (reprint author), Univ S Carolina, Dept Geog, Columbia, SC 29208 USA. NR 30 TC 122 Z9 125 U1 0 U2 16 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 FEB PY 2003 VL 84 IS 2 BP 295 EP 308 AR PII S0034-4257(02)00114-1 DI 10.1016/S0034-4257(02)00114-1 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 673RA UT WOS:000182592900011 ER PT J AU Tumer, IY Stone, RB AF Tumer, IY Stone, RB TI Mapping function to failure mode during component development SO RESEARCH IN ENGINEERING DESIGN-THEORY APPLICATIONS AND CONCURRENT ENGINEERING LA English DT Article DE failure prevention in design; function-failure similarity; design for failure; design for reliability; risk-based design ID DESIGN AB When designing aerospace systems, it is essential to provide crucial failure information for failure prevention. Failure modes and effects types of analyses and prior engineering knowledge and experience are commonly used to determine the potential modes of failures a product might encounter during its lifetime. When new products are being considered and designed, this knowledge and information is expanded upon to help designers extrapolate based on their similarity with existing products and the potential design tradeoffs. In this work, we aim to enhance this process by providing design-aid tools which derive similarities between functionality and failure modes. Specifically, this paper presents the theoretical foundations of a matrix-based approach to derive similarities that exist between different failure modes, by mapping observed failure modes to the functionality of each component, and applies it to a simple design example. The function-failure mode method is proposed to design new products or redesign existing ones with solutions for functions that eliminate or reduce the potential of a failure mode. C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. Univ Missouri, Dept Basic Engn, Rolla, MO 65409 USA. RP Tumer, IY (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. NR 28 TC 53 Z9 56 U1 0 U2 5 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL ROAD, GODALMING GU7 3DJ, SURREY, ENGLAND SN 0934-9839 J9 RES ENG DES JI Res. Eng. Design-Theory Appl. Concurrent Eng. PD FEB PY 2003 VL 14 IS 1 BP 25 EP 33 DI 10.1007/s00163-002-0024-y PG 9 WC Engineering, Multidisciplinary; Engineering, Industrial; Engineering, Manufacturing SC Engineering GA 656DX UT WOS:000181594500003 ER PT J AU Collier, MR Chornay, DJ Keller, JW Coplan, M Dionne, NJ Marji, BE Herrero, F Hirman, J Houser, J Moore, J Slavin, JA AF Collier, MR Chornay, DJ Keller, JW Coplan, M Dionne, NJ Marji, BE Herrero, F Hirman, J Houser, J Moore, J Slavin, JA TI Tomographic imaging of electron distributions: Leveraging computing power advances to produce inexpensive, low-power, lightweight, and robust instrumentation SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We describe a prototype of a novel electron spectrometer that employs a two-dimensional tomographic method to obtain the electron velocity distribution in a space plasma. The spectrometer consists of a magnetic field cavity with a single entrance aperture and a one-dimensional position sensitive microchannel plate/anode assembly electron detector. Electrons entering the instrument through the aperture which have the same component of velocity normal to the aperture plane will all strike the electron detector at the same location regardless of the magnitude of the other velocity component. Thus, the instrument performs line integrals in velocity space. By placing the instrument on a spinning spacecraft, it will provide a complete set of these integrals that may be deconvoluted using standard tomographic techniques. In many cases, basic plasma parameters can be inferred directly from the raw data without deconvolution. This instrument has advantages over conventional electrostatic analyzers: it does not require power consuming voltage stepping, makes efficient use of volume, and operates with a high duty cycle. A modified version of the instrument that is insensitive to photons and can determine three-dimensional distribution functions is also described. (C) 2003 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Raytheon Co, Sudbury, MA 01776 USA. RP Collier, MR (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Slavin, James/H-3170-2012; Keller, John/I-5097-2013; Collier, Michael/I-4864-2013 OI Slavin, James/0000-0002-9206-724X; Collier, Michael/0000-0001-9658-6605 NR 5 TC 0 Z9 0 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 2003 VL 74 IS 2 BP 1002 EP 1007 DI 10.1063/1.1532543 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 638PM UT WOS:000180579500011 ER PT J AU Lepping, RP Berdichevsky, DB Szabo, A Arqueros, C Lazarus, AJ AF Lepping, RP Berdichevsky, DB Szabo, A Arqueros, C Lazarus, AJ TI Profile of an average magnetic cloud at 1 au for the quiet solar phase: Wind observations SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; FLUX ROPES; PLASMA; ALPHA AB Using WIND magnetic field (MFI) and plasma (SWE) data, an 'average' profile of an interplanetary magnetic cloud was developed in terms of five physical (scalar) quantities based on appropriately selected individual clouds. The period of study was from early 1995 to late in 1998, primarily during the quiet part of a solar cycle. The physical quantities are: magnetic field magnitude, proton density, solar wind bulk speed, proton thermal speed, and proton plasma beta. Selection of the clouds was based on two considerations: (1) their 'quality', determined objectively from the application of a static magnetic field model of cloud field structure, had to be good, and (2) distant spacecraft approaches from the cloud axes were not accepted. Nineteen clouds resulted out of 35 original cases. A superposed epoch analysis was performed on the 5 parameters generating summary profiles of a generic magnetic cloud at 1 AU. The density within the generic magnetic cloud reached a distinct minimum near the center and peaked in the trailing part (closest to Sun) after a slow rise. The individual clouds fall into two classes, those that have such an enhanced density feature (about 1 2 of them) and those that have an overall nearly flat density profile. For the first 85% of the generic magnetic cloud the bulk speed decreased almost uniformly by 45 km s(-1) indicating marked expansion over 1 AU. The field intensity peaked very near the cloud's center but was noticeably asymmetric. Proton thermal speed was quite symmetric with local maxima at the front, center, and rear. Proton plasma beta was low throughout the cloud (0.12 on average), but had a broad minimum at its center. The relative degree of fluctuation level for the parameters ranged from the most quiet for both speed and field magnitude, to the most 'noisy' for proton plasma beta, with fluctuations in density and thermal speed at intermediate levels, all being below 0.2, based on a sample-scale of 1/100 of the cloud duration. These profiles may be useful in constraining future structural and thermodynamic models of clouds with regard to their solar birth conditions and interplanetary evolution. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Commun EER Syst, Largo, MD 20774 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Lepping, RP (reprint author), NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 35 TC 43 Z9 43 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD FEB PY 2003 VL 212 IS 2 BP 425 EP 444 DI 10.1023/A:1022938903870 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 660DM UT WOS:000181818600013 ER PT J AU Johnston, S Cordes, J AF Johnston, S Cordes, J TI Public good or commercial opportunity? Case studies in remote sensing commercialization SO SPACE POLICY LA English DT Article; Proceedings Paper CT 53rd International-Astronautical-Federation Congress CY OCT 10-19, 2002 CL HOUSTON, TEXAS SP Int Astronaut Federat AB The US government is once again attempting to commercialize the Landsat program and is asking the private sector to develop a next-generation mid-resolution remote sensing system that will provide continuity with the thirty-year data archive of Landsat data. Much of the case for commercializing the Landsat program rests on the apparently successful commercialization of high-resolution remote sensing activities coupled with the belief that conditions have changed since the failed attempt to commercialize Landsat in. the 1980s. This paper analyzes the economic, political and technical conditions that prevailed in the 1980s as well as conditions that might account for the apparent success of the emerging high-resolution remote sensing industry today. Lessons are gleaned for the future of the Landsat program. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. George Washington Univ, Washington, DC 20052 USA. RP Johnston, S (reprint author), NASA, Goddard Space Flight Ctr, Code 920-1,Greenbelt Rd, Greenbelt, MD 20771 USA. NR 12 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0265-9646 J9 SPACE POLICY JI Space Policy PD FEB PY 2003 VL 19 IS 1 BP 23 EP 31 DI 10.1016/S0265-9646(02)00070-X PG 9 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 650DN UT WOS:000181247500004 ER PT J AU Miyoshi, K Lerch, BA Draper, SL AF Miyoshi, K Lerch, BA Draper, SL TI Fretting fatigue and wear SO TRIBOLOGY INTERNATIONAL LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Miyoshi, K (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 106-5, Cleveland, OH 44135 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-679X J9 TRIBOL INT JI Tribol. Int. PD FEB PY 2003 VL 36 IS 2 BP 69 EP 69 AR PII S0301-679X(02)00133-0 PG 1 WC Engineering, Mechanical SC Engineering GA 632QF UT WOS:000180233800001 ER PT J AU Miyoshi, K Lerch, BA Draper, SL AF Miyoshi, K Lerch, BA Draper, SL TI Fretting wear of Ti-48Al-2Cr-2Nb SO TRIBOLOGY INTERNATIONAL LA English DT Article DE titanium alummide (gamma-TiAl); fretting wear; fatigue; oxidation; high temperature ID FATIGUE BEHAVIOR AB An investigation was conducted to examine the wear behavior of gamma titanium aluminide (Ti-48Al-2Cr-2Nb in atomic percent) in contact with a typical nickel-base superalloy under repeated microscopic vibratory motion in air at temperatures from 296-823 K. The surface damage observed on the interacting surfaces of both Ti-48Al-2Cr-2Nb and superalloy consisted of fracture pits, oxides, metallic debris, scratches, craters, plastic deformation, and cracks. The Ti-48Al-2Cr-2Nb transferred to the superalloy at all fretting conditions and caused scuffing or galling. The increasing rate of oxidation at elevated temperatures led to a drop in Ti-48Al-2Cr-2Nb wear at 473 K. Mild oxidative wear was observed at 473 K. However, fretting wear increased as the temperature was increased from 473-823 K. At 723 and 823 K, oxide disruption generated cracks, loose wear debris, and pits on the Ti-48Al-2Cr-2Nb wear surface. Ti-48Al-2Cr-2Nb wear generally decreased with increasing fretting frequency. Both increasing slip amplitude and increasing load tended to produce more metallic wear debris, causing severe abrasive wear in the contacting metals. Published by Elsevier Science Ltd. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Miyoshi, K (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 15 TC 32 Z9 37 U1 3 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-679X J9 TRIBOL INT JI Tribol. Int. PD FEB PY 2003 VL 36 IS 2 BP 145 EP 153 AR PII S0301-679X(02)00142-1 DI 10.1016/S0301-679X(02)00142-1 PG 9 WC Engineering, Mechanical SC Engineering GA 632QF UT WOS:000180233800009 ER PT J AU Jansen, MJ Jones, WR Pepper, SV AF Jansen, MJ Jones, WR Pepper, SV TI Evaluation of an in-situ liquid lubrication system for space mechanisms using a vacuum spiral orbit tribometer SO TRIBOLOGY LETTERS LA English DT Article DE space tribology; spiral orbit tribometer AB Many moving mechanical assemblies (MMAs) for space applications rely on a small, initial charge of lubricant for the entire mission lifetime, often in excess of five years. In many cases, the premature failure of a lubricated component can result in mission failure. If lubricant could be re-supplied to the contact in-situ, the life of the MMA could be extended. A vacuum spiral orbit tribometer (SOT) was modified to accept a device to supply re-lubrication during testing. It was successfully demonstrated that a liquid lubricant (Pennzane(R)/Nye 2001A) could be evaporated into a contact during operation, lowering the friction coefficient and therefore extending the life of the system. C1 Sest Inc, Middleburg Hts, OH 44130 USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Jansen, MJ (reprint author), Sest Inc, Middleburg Hts, OH 44130 USA. NR 23 TC 6 Z9 6 U1 3 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD FEB PY 2003 VL 14 IS 2 BP 61 EP 67 DI 10.1023/A:1021791817718 PG 7 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 629KJ UT WOS:000180048600002 ER PT J AU Bertucci, C Mazelle, C Crider, DH Vignes, D Acuna, MH Mitchell, DL Lin, RP Connerney, JEP Reme, H Cloutier, PA Ness, NF Winterhalter, D AF Bertucci, C Mazelle, C Crider, DH Vignes, D Acuna, MH Mitchell, DL Lin, RP Connerney, JEP Reme, H Cloutier, PA Ness, NF Winterhalter, D TI Magnetic field draping enhancement at the Martian magnetic pileup boundary from Mars global surveyor observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND INTERACTION; VENUS; MAGNETOSPHERE; MAGNETOTAIL; ENCOUNTER AB The Magnetic Pileup Boundary (MPB) is a sharp and permanent plasma boundary located between the bow shock and the ionospheric boundary, reported so far at Mars and comets. We use Mars Global Surveyor Magnetometer data to do a quantitative analysis of the magnetic field geometry in the surroundings of the Martian MPB. As a result, we report for the first time a dramatic enhancement of the magnetic field draping at this boundary. This new feature, already reported at comets, is independent of the presence of the crustal magnetic sources. Comparisons with similar results across the Martian and cometary magnetotails reveal that the MPB and the magnetotail boundary are connected. Moreover, the study of this feature can help understand the physics of the Venusian magnetic barrier. C1 Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. NASA, Jet Prop Lab, Pasadena, CA USA. RP Bertucci, C (reprint author), Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. RI connerney, john/I-5127-2013; Hurley, Dana/F-4488-2015; OI Hurley, Dana/0000-0003-1052-1494; Bertucci, Cesar/0000-0002-2540-5384 NR 20 TC 54 Z9 54 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 31 PY 2003 VL 30 IS 2 AR 1099 DI 10.1029/2002GL015713 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678YB UT WOS:000182893300005 ER PT J AU Thompson, AM Witte, JC Oltmans, SJ Schmidlin, FJ Logan, JA Fujiwara, M Kirchhoff, VWJH Posny, F Coetzee, GJR Hoegger, B Kawakami, SJ Ogawa, T Fortuin, JPF Kelder, HM AF Thompson, AM Witte, JC Oltmans, SJ Schmidlin, FJ Logan, JA Fujiwara, M Kirchhoff, VWJH Posny, F Coetzee, GJR Hoegger, B Kawakami, SJ Ogawa, T Fortuin, JPF Kelder, HM TI Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology - 2. Tropospheric variability and the zonal wave-one SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE free-words-ozone; tropospheric ozone; ozonesondes; satellite ozone; tropical climatology; wave-one; biomass burning; El Nino; satellite retrievals ID QUASI-BIENNIAL OSCILLATIONS; GROUND-BASED OBSERVATIONS; INDIAN-OCEAN; VERTICAL-DISTRIBUTION; FIELD OBSERVATIONS; DEEP CONVECTION; COLUMN OZONE; DRY SEASON; ATLANTIC; TRACE AB The first view of stratospheric and tropospheric ozone variability in the Southern Hemisphere tropics is provided by a 3-year record of ozone soundings from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network (http://croc.gsfc.nasa.gov/shadoz). Observations covering 1998-2000 were made over Ascension Island, Nairobi ( Kenya), Irene ( South Africa), Reunion Island, Watukosek (Java), Fiji, Tahiti, American Samoa, San Cristobal (Galapagos), and Natal (Brazil). Total, stratospheric, and tropospheric column ozone amounts usually peak between August and November. Other features are a persistent zonal wave-one pattern in total column ozone and signatures of the quasi-biennial oscillation (QBO) in stratospheric ozone. The wave-one is due to a greater concentration of free tropospheric ozone over the tropical Atlantic than the Pacific and appears to be associated with tropical general circulation and seasonal pollution from biomass burning. Tropospheric ozone over the Indian and Pacific Oceans displays influences of the waning 1997-1998 El Nino, seasonal convection, and pollution transport from Africa. The most distinctive feature of SHADOZ tropospheric ozone is variability in the data, e. g., a factor of 3 in column amount at 8 of 10 stations. Seasonal and monthly means may not be robust quantities because statistics are frequently not Gaussian even at sites that are always in tropical air. Models and satellite retrievals should be evaluated on their capability for reproducing tropospheric variability and fine structure. A 1999 2000 ozone record from Paramaribo, Surinam (6degreesN, 55degreesW) (also in SHADOZ) shows a marked contrast to southern tropical ozone because Surinam is often north of the Intertropical Convergence Zone (ITCZ). A more representative tropospheric ozone climatology for models and satellite retrievals requires additional Northern Hemisphere tropical data. C1 NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. NASA, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Kyoto, Japan. INPE Lab Ozonio, Sao Jose Dos Campos, Brazil. Univ Reunion, St Denis, Reunion. S African Weather Serv, ZA-0001 Pretoria, South Africa. Swiss Aerol Observ, Meteo Suissem, Payerne, Switzerland. NASDA Earth Observat Res Ctr, Tokyo, Japan. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Tech Univ Eindhoven, NL-5600 MB Eindhoven, Netherlands. RP Thompson, AM (reprint author), NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Bldg 33,Room E417,Code 916, Greenbelt, MD 20771 USA. EM anne.m.thompson@nasa.gov RI Fujiwara, Masatomo/F-7852-2012; Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 69 TC 141 Z9 143 U1 3 U2 12 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 31 PY 2003 VL 108 IS D2 AR 8241 DI 10.1029/2002JD002241 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678ZU UT WOS:000182897200010 ER PT J AU Polito, PS Liu, WT AF Polito, PS Liu, WT TI Global characterization of Rossby waves at several spectral bands SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE Rossby waves; tropical instability waves; FIR filters; Kelvin waves; phase speed ID TROPICAL NORTH PACIFIC; LONG WAVES; PROPAGATION; OCEAN; ALTIMETER; SATELLITE; TOPEX/POSEIDON; GENERATION; ATLANTIC; MOTIONS AB [1] Global sea surface height anomaly signals from the TOPEX/Poseidon satellite altimeter from 1992 to 2000 are filtered into several spectral bands. These bands include propagating (Rossby, Kelvin, and tropical instability waves) and nonpropagating (annual and interannual basin-scale variability and eddies) signals. These signals are decomposed through a series of finite impulse response band-pass filters. Phase speed, period, wavelength, and amplitude are estimated. Signal-to-noise ratio, methodological errors, and natural variability are also estimated. Results are shown for the Pacific, Atlantic, and Indian basins for four Rossby wave components with periods between 3 and 24 months. Equatorial Kelvin waves and tropical instability waves are shown as peripheral results. The clearest and most energetic wave signals are generally observed for annual Rossby waves. Semiannual Rossby waves often have the largest amplitudes near the tropics. The Rossby wave phase speeds are in agreement with the linear theory, except for a similar to25% bias toward high speeds found in mid to high latitudes. This revitalizes the idea that on the average the Rossby wave signal in the ocean is in the form of free waves. C1 Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Paulo, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Polito, PS (reprint author), Inst Nacl Pesquisas Espaciais, Av Astronautas 1758, BR-12227010 Sao Paulo, Brazil. RI Polito, Paulo/F-3040-2013 OI Polito, Paulo/0000-0003-2217-3853 NR 36 TC 42 Z9 44 U1 0 U2 6 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 31 PY 2003 VL 108 IS C1 AR 3018 DI 10.1029/2000JC000607 PG 18 WC Oceanography SC Oceanography GA 679DD UT WOS:000182904800001 ER PT J AU Schmidt, GA Shindell, DT AF Schmidt, GA Shindell, DT TI Atmospheric composition, radiative forcing, and climate change as a consequence of a massive methane release from gas hydrates SO PALEOCEANOGRAPHY LA English DT Article ID PALEOCENE THERMAL MAXIMUM; POLAR STRATOSPHERIC CLOUDS; GREENHOUSE-GAS; EOCENE BOUNDARY; CIRCULATION; OZONE; SIMULATION; CHRONOLOGY; RECOVERY; RECORDS AB [1] The massive perturbation to global climate and the carbon cycle during the Paleocene/Eocene Thermal Maximum (PETM) (approx. 55.5 Ma) may have been forced by a catastrophic release of methane gas (CH4) from hydrate deposits on the continental slope. We investigate whether reported PETM paleotemperature and paleo-CO2 proxies are consistent with this hypothesis by considering the impact of large increases in CH4 emissions to the atmosphere. Significant effects on atmospheric chemistry and CH4 lifetime are seen for a range of plausible emission rates (1500 Gt carbon over 500 - 20,000 years). The resulting peak anomalous radiative forcing is 1.5 - 13.3 W/m(2) depending on the emission scenario. The scenarios most closely matched to the PETM carbon isotope excursion have peak forcing of around 3 W/m(2), which translates to peak temperature changes as a function of latitude that are a reasonable match to derived estimates. High CH4 levels and enhanced stratospheric water vapor amounts persist for as long as do the emissions and are responsible for more of the peak radiative forcing than CO2 levels, although results are sensitive to the background climate state and base CH4 concentration. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Ctr Climate Syst Res, New York, NY 10025 USA. RP Schmidt, GA (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gschmidt@giss.nasa.gov RI Shindell, Drew/D-4636-2012; Schmidt, Gavin/D-4427-2012 OI Schmidt, Gavin/0000-0002-2258-0486 NR 44 TC 51 Z9 51 U1 1 U2 24 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 EI 1944-9186 J9 PALEOCEANOGRAPHY JI Paleoceanography PD JAN 31 PY 2003 VL 18 IS 1 AR 1004 DI 10.1029/2002PA000757 PG 9 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA 679FA UT WOS:000182909000001 ER PT J AU Dixon, ET AF Dixon, ET TI Interpretation of helium and neon isotopic heterogeneity in Icelandic basalts SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Iceland; noble; gas; helium; neon ID RARE-GAS SYSTEMATICS; NOBLE-GASES; REYKJANES RIDGE; MANTLE-PLUME; NORTHWEST ICELAND; LOIHI SEAMOUNT; SOLAR-WIND; CONSTRAINTS; ARGON; EARTH AB New noble gas data from stepwise heating of nine samples from the Reykjanes Peninsula, Iceland, show total gas He-3/He-4 ratios ranging from relatively low values of 11 +/- 1 R/R-a to higher values of 21 +/- 2 R/R-a (where R-a = atmospheric He-3/He-4 ratio). These values are similar to previously measured ratios in Icelandic basalts, and higher than the average mid-ocean ridge basalt (MORB) He-3/He-4 ratio of similar to8.5 R/R-a. Significantly, new neon isotopic data from five of these samples lie on, or above, the MORB trend in the neon three-isotope plot. These data provide the first strong evidence for a MORB-like neon isotopic component in Icelandic basalts. The remaining data lie on or near the air-solar mixing line, or within 1sigma of the atmospheric ratio. The combined new and previously published Icelandic mantle neon isotopic ratios range from MORB-like to solar-like compositions. The possible origins of this significant noble gas isotopic heterogeneity are evaluated in terms of two previously published models, the plume source model and the binary mixing model [Moreira et al., Earth Panct. Sci. Lett. 185 (2001) 15-23]. The plume source model is evaluated by comparison of the calculated He-3/Ne-22 elemental ratios from Iceland with the published estimates of the He-3/Ne-22 ratios in the solar nebula (1.9) and MORB (similar to10). Most Icelandic He-3/Ne-22 (calculated) ratios are between similar to1 and 12 and suggest the Icelandic plume source is quite heterogeneous, but alternative explanations are possible. The heterogeneous Icelandic helium and neon isotopic ratios that give rise to the range in calculated He-3/Ne-22 ratios are also consistent with binary mixing between solar-like Icelandic plume- and MORB-derived noble gases. These end-members have specifically defined isotopic ratios but elemental ratios that may be variably modified. A large degree of recent relative elemental fractionation of He/Ne ratios in the Icelandic plume and MORB end-members would be needed to produce the observed range in isotopic ratios. The binary mixing model was further evaluated by comparison of Icelandic data with those from the Shona Ridge, a locality where binary mixing is believed to occur. In a plot of calculated He-3/Ne-22 and Ne-21/Ne-22 ratios, the Icelandic and Shona Ridge data form divergent linear trends that can be reconciled with binary mixing and that, interestingly, intersect at values of 1.6 and 0.036, respectively. These values are similar to the estimated solar nebula composition (1.9 and 0.0328). Such low calculated He-3/Ne-22 ratios have not been determined previously in terrestrial mantle-derived samples and may suggest that the plume source contains a component that is relatively unfractionated compared with the primordial solar nebula composition. Published steady-state upper mantle models require that the He-3/Ne-22 ratios in the plume (lower mantle) and MORB (upper mantle) sources are about equal to each other. The calculated He-3/Ne-22 ratio of near 1.6, inferred to represent the Icelandic and Shona Ridge mantle plume source composition, is dissimilar from the estimated MORB He-3/Ne-22 ratio of near 10. This appears to suggest the upper mantle is not at steady state with respect to the plume source mantle. The results of this study do not rule out the possible existence of Icelandic plume source noble gas elemental and isotopic heterogeneity. However, they do suggest that evidence for plume source heterogeneity may be obscured as a result of relatively shallow-level elemental fractionation and binary mixing processes. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. RP Dixon, ET (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1,Mail Code SR, Houston, TX 77058 USA. NR 65 TC 22 Z9 22 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD JAN 30 PY 2003 VL 206 IS 1-2 BP 83 EP 99 AR PII S0012-821X(02)01071-3 DI 10.1016/S0012-821X(02)01071-3 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 642EY UT WOS:000180792300007 ER PT J AU DiNunno, B Davis, D Chen, G Gregory, G Sachse, G Anderson, B Vay, S Avery, M Ridley, B Carroll, M Walega, J Montzka, D Grahek, F Bradshaw, J Sandholm, S Kondo, Y Kok, G Blake, D Blake, N Barrick, J Fuelberg, H Martin, B Balok, A AF DiNunno, B Davis, D Chen, G Gregory, G Sachse, G Anderson, B Vay, S Avery, M Ridley, B Carroll, M Walega, J Montzka, D Grahek, F Bradshaw, J Sandholm, S Kondo, Y Kok, G Blake, D Blake, N Barrick, J Fuelberg, H Martin, B Balok, A TI Central/eastern North Pacific photochemical precursor distributions for fall/spring seasons as defined by airborne field studies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; Pacific; troposphere; photochemistry ID CARBON-MONOXIDE MEASUREMENTS; PEM-TROPICS-A; SPRING OZONE MAXIMUM; TROPOSPHERIC OZONE; BOUNDARY-LAYER; NITRIC-OXIDE; EXPLORATORY MISSION; MAUNA-LOA; GLOBAL DISTRIBUTION; WEST-A AB Data from 10 aircraft programs recorded over the central/eastern North Pacific (180degrees-120degreesW, 0degrees-45degreesN) were assembled for the purpose of assessing an atmospheric chemical climatology for this region. It represents an early effort at carrying out this task and, thus, it can be expected to undergo many updates in the future. Such a database is useful in both gaining further insights concerning the fundamental processes controlling the chemistry of this region as well as serving as an important baseline by which to evaluate future change. Critical photochemical precursors examined included O-3, CO, NOx, and H2O. In addition, the distribution profiles for select nonmethane hydrocarbons were explored. The precursor data were analyzed according to latitude, pressure altitude, and season of the year. Contrasting the spring and fall measurements, major trends that surfaced in both ozone and CO included observing elevated levels in spring compared to fall, with the largest spring increase occurring at latitudes north of 15degreesN. Both NOx and H2O showed trends quite different from that of CO and O-3, with an indication of higher mixing ratio levels during the fall season. Variations in precursor distribution patterns within a season will be explained based on climatological flow patterns for the region and the resulting connection to source regions. Where possible, comparisons were performed with other sampling strategies, including ground-based observations, sonde, and satellite data, and data collected during shuttle missions. Overall, these comparisons revealed a reasonably high level of correspondence between the airborne ensemble data and those collected using other sampling strategies. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Tokyo, Adv Sci & Technol Res Ctr, Tokyo, Japan. Natl Ctr Atmospher Res, Res Aviat Facil, Boulder, CO 80307 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. RP DiNunno, B (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM bd42@prism.gatech.edu RI Kondo, Yutaka/D-1459-2012 NR 87 TC 2 Z9 2 U1 0 U2 1 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 30 PY 2003 VL 108 IS D2 AR 8240 DI 10.1029/2001JD001044 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678YN UT WOS:000182894400003 ER PT J AU Staudt, AC Jacob, DJ Ravetta, F Logan, JA Bachiochi, D Krishnamurti, TN Sandholm, S Ridley, B Singh, HB Talbot, B AF Staudt, AC Jacob, DJ Ravetta, F Logan, JA Bachiochi, D Krishnamurti, TN Sandholm, S Ridley, B Singh, HB Talbot, B TI Sources and chemistry of nitrogen oxides over the tropical Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; nitrogen oxides; troposphere; lightning; convection; tropics ID MARCH-APRIL 1999; UPPER TROPOSPHERE; EXPLORATORY MISSION; SOUTH-PACIFIC; REACTIVE NITROGEN; NITRIC-ACID; ORGANIC-COMPOUNDS; ICE SURFACES; MODEL; TRANSPORT AB We examine the sources and chemistry affecting nitrogen oxides (NOx = NO + NO2) over the tropical Pacific (30degreesS-20degreesN) using observations from the Pacific Exploratory Mission to the Tropics B (PEM-Tropics B) aircraft mission conducted in March-April 1999. A global model of tropospheric chemistry driven by assimilated meteorological data is used to interpret the observations. Median concentrations observed over the South Pacific during PEM-Tropics B were 7 pptv NO, 16 pptv peroxyacetyl nitrate ( PAN), and 34 pptv nitric acid (HNO3); the model generally reproduces these observations but overestimates those over the North Pacific. Lightning was the largest source of these species in the equatorial and South Pacific tropospheric column and in the tropical North Pacific upper troposphere. The oceanic source of acetone implied by high observations of acetone concentrations (mean 431 pptv) allows an improved simulation of PAN/NOx chemistry. However, the high acetaldehyde concentrations (mean 78 pptv) measured throughout the troposphere are inconsistent with our understanding of acetaldehyde and PAN chemistry. Simulated concentrations of HNO3 and HNO3/NOx are highly sensitive to the model representation of deep convection and associated HNO3 scavenging. Chemical losses of NOx during PEM-Tropics B exceed chemical sources by a factor of 2 in the South Pacific upper troposphere. The chemical imbalance, also apparent in the low observed HNO3/NOx ratio, is explained by NOx injection from lightning and by frequent convective overturning which depletes HNO3. The observed imbalance was less during the PEM-Tropics A campaign in September 1996, when aged biomass burning effluents over the South Pacific pushed the NOx budget toward chemical steady state. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Complex Syst Res Ctr, Durham, NH 03824 USA. RP Staudt, AC (reprint author), Natl Acad, Natl Res Council, Board Atmospher Sci & Climate, 500 5th St NW, Washington, DC 20001 USA. EM astaudt@nas.edu; djj@io.harvard.edu; francois.ravetta@aero.jussieu.fr; jal@io.harvard.edu; tnk@met.fsu.edu; ss27@prism.gatech.edu; ridley@acd.ucar.edu; hsingh@mail.arc.nasa.gov; robert.talbot@unh.edu NR 77 TC 37 Z9 38 U1 1 U2 9 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 30 PY 2003 VL 108 IS D2 AR 8239 DI 10.1029/2002JD002139 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678YN UT WOS:000182894400005 ER PT J AU Thompson, AM Witte, JC McPeters, RD Oltmans, SJ Schmidlin, FJ Logan, JA Fujiwara, M Kirchhoff, VWJH Posny, F Coetzee, GJR Hoegger, B Kawakami, S Ogawa, T Johnson, BJ Vomel, H Labow, G AF Thompson, AM Witte, JC McPeters, RD Oltmans, SJ Schmidlin, FJ Logan, JA Fujiwara, M Kirchhoff, VWJH Posny, F Coetzee, GJR Hoegger, B Kawakami, S Ogawa, T Johnson, BJ Vomel, H Labow, G TI Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology - 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; ozonesondes; satellite ozone; tropical climatology ID TROPOSPHERIC COLUMN OZONE; MODIFIED-RESIDUAL METHOD; GAS EXPERIMENT DATA; VERTICAL-DISTRIBUTION; INDIAN-OCEAN; INTERCOMPARISON CAMPAIGN; STRATOSPHERIC AEROSOL; FIELD OBSERVATIONS; BREWER-MAST; NIMBUS 7 AB A network of 10 southern hemisphere tropical and subtropical stations, designated the Southern Hemisphere Additional Ozonesondes (SHADOZ) project and established from operational sites, provided over 1000 ozone profiles during the period 1998-2000. Balloon-borne electrochemical concentration cell (ECC) ozonesondes, combined with standard radiosondes for pressure, temperature, and relative humidity measurements, collected profiles in the troposphere and lower to midstratosphere at: Ascension Island; Nairobi, Kenya; Irene, South Africa; Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristobal, Galapagos; and Natal, Brazil. The archived data are available at: . In this paper, uncertainties and accuracies within the SHADOZ ozone data set are evaluated by analyzing: (1) imprecisions in profiles and in methods of extrapolating ozone above balloon burst; (2) comparisons of column-integrated total ozone from sondes with total ozone from the Earth-Probe/Total Ozone Mapping Spectrometer ( TOMS) satellite and ground-based instruments; and (3) possible biases from station to station due to variations in ozonesonde characteristics. The key results are the following: (1) Ozonesonde precision is 5%. (2) Integrated total ozone column amounts from the sondes are usually to within 5% of independent measurements from ground-based instruments at five SHADOZ sites and overpass measurements from the TOMS satellite (version 7 data). (3) Systematic variations in TOMS-sonde offsets and in ground-based-sonde offsets from station to station reflect biases in sonde technique as well as in satellite retrieval. Discrepancies are present in both stratospheric and tropospheric ozone. (4) There is evidence for a zonal wave-one pattern in total and tropospheric ozone, but not in stratospheric ozone. C1 NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. NASA, Wallops Flight Facil, Wallops Isl, VA 23337 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Kyoto, Japan. INPE Lab Ozonio, Sao Jose Dos Campos, Brazil. Univ Reunion, St Denis, Reunion. S African Weather Serv, ZA-0001 Pretoria, South Africa. Swiss Aerol Observ, Meteo Suisse, Payerne, Switzerland. NASDA Earth Observat Res Ctr, Tokyo, Japan. Sci Syst & Applicat Inc, Lanham, MD USA. RP Thompson, AM (reprint author), NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Bldg 33,Room E417,Mail Code 916, Greenbelt, MD 20771 USA. EM anne.m.thompson@nasa.gov RI Fujiwara, Masatomo/F-7852-2012; McPeters, Richard/G-4955-2013; Thompson, Anne /C-3649-2014 OI McPeters, Richard/0000-0002-8926-8462; Thompson, Anne /0000-0002-7829-0920 NR 56 TC 245 Z9 248 U1 1 U2 26 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 30 PY 2003 VL 108 IS D2 AR 8238 DI 10.1029/2001JD000967 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 678YN UT WOS:000182894400002 ER PT J AU Hinson, DP Wilson, RJ Smith, MD Conrath, BJ AF Hinson, DP Wilson, RJ Smith, MD Conrath, BJ TI Stationary planetary waves in the atmosphere of Mars during southern winter SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; atmosphere; meteorology; dynamics ID THERMAL EMISSION SPECTROMETER; RADIO OCCULTATION MEASUREMENTS; GENERAL-CIRCULATION MODEL; GLOBAL SURVEYOR; MARTIAN ATMOSPHERE; ACCELEROMETER; HEMISPHERE; RESOLUTION; EDDIES; TIDES AB [1] We report new observations of stationary planetary waves in the Southern Hemisphere of Mars by Mars Global Surveyor (MGS). We focus on a period during midwinter (L-s = 134degrees - 160degrees) when independent observations were acquired by two techniques. Radio occultation experiments sounded the atmosphere at essentially fixed latitude (similar to68degreesS) and local time (similar to1030), yielding profiles of geopotential and temperature between the surface and the 9 Pa pressure level. Observations by the Thermal Emission Spectrometer (TES) included systematic limb sounding at nine discrete latitudes and two local times (similar to0200 and similar to1500), yielding temperature profiles at pressures of 1 - 100 Pa. We supplemented these data with a simulation by a Mars general circulation model (MGCM), which provides an accurate synthesis of the observations. These stationary planetary waves have significant amplitudes at zonal wave numbers s = 1 and 2. The s = 1 component propagates vertically, as reflected by a westward tilt with increasing height in the geopotential and temperature fields and a net poleward eddy heat flux. The peak amplitude at s = 1 is similar to1 km in geopotential height and similar to7 K in temperature. The geopotential field of the s = 2 component is "barotropic'' in character, which results through hydrostatic balance in a distinctive temperature field. The peak amplitude at s = 2 is similar to700 m in geopotential height and 4 - 6 K in temperature. C1 Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Stanford Univ, Dept Elect Engn, Stanford, CA 94305 USA. EM hinson@nimbus.stanford.edu; rjw@gfdl.noaa.gov; Michael.D.Smith.1@gsfc.nasa.gov; barney@chryse.gsfc.nasa.gov RI Smith, Michael/C-8875-2012 NR 26 TC 25 Z9 25 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JAN 30 PY 2003 VL 108 IS E1 AR 5004 DI 10.1029/2002JE001949 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 679DJ UT WOS:000182905300002 ER PT J AU Wang, A Haskin, LA Lane, AL Wdowiak, TJ Squyres, SW Wilson, RJ Hovland, LE Manatt, KS Raouf, N Smith, CD AF Wang, A Haskin, LA Lane, AL Wdowiak, TJ Squyres, SW Wilson, RJ Hovland, LE Manatt, KS Raouf, N Smith, CD TI Development of the Mars microbeam Raman spectrometer (MMRS) SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Raman spectroscopy; Mars in-situ mineralogy; planetary on-surface mineral identification; water on Mars; miniaturized Raman spectrometer; Mars microbeam Raman spectrometer ID IN-SITU; SPECTROSCOPIC CHARACTERIZATION; MINERAL IDENTIFICATION; MARTIAN METEORITE; PROBE DESIGNS; SURFACE; SPECTRA; MISSIONS; FEATURES; ANALOGS AB [1] Raman spectroscopy is a powerful tool for mineral characterization and for detection of water and organic and inorganic forms of carbon. The Mars microbeam Raman spectrometer (MMRS) is designed for close-up analysis of rocks and soils in planetary surface exploration. The MMRS consists of a probe ( in a flight unit to be deployed by a robotic arm) and a spectrograph, laser source, and electronics ( in a flight unit to reside on a rover or lander). The Raman probe has a scanning optical bench that enables a 1-cm linear traverse across a target rock or soil, both on target materials as encountered and on fresh surfaces of rocks exposed by abrasion or coring. From these spectra, one can identify major, minor, and trace minerals, obtain their approximate relative proportions, and determine chemical features ( e. g., Mg/Fe ratio) and rock textural features ( e. g., mineral clusters, amygdular fill, and veins). One can also detect and identify organic species, graphitic carbon, and water-bearing phases. Extensive performance tests have been done on a brassboard model of the MMRS using a variety of geological materials ( minerals, rocks, Martian meteorites, etc.). These tests show that a Raman spectrometer can be built that is suitably miniaturized, sufficiently robust, and low enough in power usage to serve as an on-surface planetary instrument, yet the spectrometer can retain high detection sensitivity and yield near laboratory quality spectra over a broad wavelength range. These features are essential to provide definitive mineralogy in a planetary exploration. C1 Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Washington Univ, McDonnell Ctr Space Sci, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Observat Syst Div, Pasadena, CA 91109 USA. Univ Alabama, Dept Phys, Birmingham, AL 35294 USA. Cornell Univ, Ctr Radiophys & Space Phys, Ithaca, NY 14853 USA. Swales Aerosp Corp, Engn Serv, Pasadena, CA 91107 USA. RP Wang, A (reprint author), Washington Univ, Dept Earth & Planetary Sci, 1 Brookings Dr, St Louis, MO 63130 USA. NR 56 TC 64 Z9 64 U1 2 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JAN 30 PY 2003 VL 108 IS E1 AR 5005 DI 10.1029/2002JE001902 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 679DJ UT WOS:000182905300001 ER PT J AU Palmroth, M Pulkkinen, TI Janhunen, P Wu, CC AF Palmroth, M Pulkkinen, TI Janhunen, P Wu, CC TI Stormtime energy transfer in global MHD simulation SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE energy transfer; magnetic storms; magnetopause; solar wind-magnetosphere coupling ID INTERPLANETARY MAGNETIC-FIELD; SOLAR-WIND; SUBSTORM ONSET; MAGNETOSPHERE; MAGNETOPAUSE; MAGNETOHYDRODYNAMICS; RECONNECTION; MAGNETOTAIL; SCHEME AB [1] We use a three-dimensional global magnetohydrodynamic (MHD) simulation code to examine the energy flow from the solar wind to the magnetosphere. We simulate a major magnetic storm, which occurred on 6-7 April 2000. During this disturbed period the energy input to the magnetosphere was highly enhanced. For the energy transfer calculation a method for identifying the magnetopause surface from the simulation is developed. We calculate the total energy flux component normal to the magnetopause surface, thus giving the energy flux transferred from the solar wind to the magnetosphere. With this method we identify the locations on the magnetopause surface where significant energy transfer takes place during the storm evolution. During the main phase the energy is transferred from the plane parallel and antiparallel to the interplanetary magnetic field (IMF) clock angle Sunward of X-GSE > -10 R-E. During the recovery phase most of the energy is transferred in the low-latitude equatorial sectors Sunward of the dawn-dusk terminator. We discuss the possible explanations to the observed energy transfer locations. We also compare the time evolution of the total transferred energy to the time evolution of the empirical epsilon parameter calculated from the solar wind parameters. During the main phase the total transferred energy in the simulation is well correlated with epsilon, although it is about four times larger. During the recovery phase the total transferred energy and epsilon are not well correlated, and their ratio is much larger than during the main phase. Finally, we discuss limitations of the developed method, which is based on calculating fluxes through surfaces using surface integrals. C1 Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Palmroth, M (reprint author), Finnish Meteorol Inst, POB 503, FIN-00101 Helsinki, Finland. RI Pulkkinen, Tuija/D-8403-2012 OI Pulkkinen, Tuija/0000-0002-6317-381X NR 30 TC 67 Z9 71 U1 0 U2 9 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 2003 VL 108 IS A1 AR 1048 DI 10.1029/2002JA009446 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679ER UT WOS:000182908200004 ER PT J AU Chapman, CR Morrison, D AF Chapman, CR Morrison, D TI No reduction in risk of a massive asteroid impact SO NATURE LA English DT Letter C1 SW Res Inst, Boulder, CO 80302 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Chapman, CR (reprint author), SW Res Inst, 1050 Walnut St, Boulder, CO 80302 USA. NR 2 TC 2 Z9 2 U1 2 U2 3 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 30 PY 2003 VL 421 IS 6922 BP 473 EP 473 DI 10.1038/421473b PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 640DB UT WOS:000180670600016 PM 12556862 ER PT J AU Manney, GL Sabutis, JL Pawson, S Santee, ML Naujokat, B Swinbank, R Gelman, ME Ebisuzaki, W AF Manney, GL Sabutis, JL Pawson, S Santee, ML Naujokat, B Swinbank, R Gelman, ME Ebisuzaki, W TI Lower stratospheric temperature differences between meteorological analyses in two cold Arctic winters and their impact on polar processing studies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratosphere; temperatures; meteorological analyses; polar processing ID DATA ASSIMILATION SCHEME; MICROWAVE LIMB SOUNDER; DURATION BALLOON DATA; SSI ANALYSIS SYSTEM; OZONE LOSS; VARIATIONAL ASSIMILATION; VORTEX CONDITIONS; MLS OBSERVATIONS; DENITRIFICATION; IMPLEMENTATION AB A quantitative comparison of six meteorological analyses is presented for the cold 1999/2000 and 1995/1996 Arctic winters. Using different analyzed data sets to obtain temperatures and temperature histories can have significant consequences. The area with temperatures below a polar stratospheric cloud (PSC) formation threshold commonly varies by similar to25% between the analyses, with some differences over 50%. Biases between analyses vary from year to year; in January 2000, Met Office analyses were coldest and National Centers for Environmental Prediction (NCEP) analyses were warmest, while NCEP analyses were usually coldest in 1995/1996 and NCEP/National Center for Atmospheric Research Reanalysis (REAN) were usually warmest. Freie Universitat Berlin analyses are often colder than others at T less than or similar to 205 K. European Centre for Medium-Range Weather Forecasts (ECMWF) temperatures agreed better with other analyses in 1999/2000, after improvements in the assimilation system, than in 1995/1996. Temperature history case studies show substantial differences using Met Office, NCEP, REAN, ECMWF, and NASA Data Assimilation Office (DAO) analyses. In January 2000 ( when a large cold region was centered in the polar vortex), all analyses gave qualitatively similar results. However, in February 2000 ( a much warmer period) and in January and February 1996 ( comparably cold to January 2000 but with the cold region near the polar vortex edge), distributions of "potential PSC lifetimes" and total time spent below a PSC formation threshold varied significantly between the analyses. Largest peaks in "PSC lifetime" distributions in January 2000 were at 4-6 and 11-14 days, while in 1996 they were at 1-3 days. Different meteorological conditions in comparably cold winters have a large impact on expectations for PSC formation and on the effects of discrepancies between different meteorological analyses. Met Office, NCEP, REAN, ECMWF, and DAO analyses are commonly used in modeling polar processes; the choice of analysis can strongly influence the results of such studies. C1 New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NV USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. New Mexico Highlands Univ, Sch Educ, Las Vegas, NV USA. New Mexico Highlands Univ, Dept Phys, Las Vegas, NV USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Free Univ Berlin, Inst Meteorol, D-12165 Berlin, Germany. Meteorol Off, Bracknell RG12 2SZ, Berks, England. NOAA, Climate Predict Ctr, Natl Ctr Environm Predict, Natl Weather Serv, Washington, DC USA. RP New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NV USA. RI Ebisuzaki, Toshikazu/N-6998-2014; Pawson, Steven/I-1865-2014 OI Ebisuzaki, Toshikazu/0000-0002-3918-1166; Pawson, Steven/0000-0003-0200-717X NR 61 TC 37 Z9 37 U1 1 U2 3 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 29 PY 2003 VL 108 IS D5 AR 8328 DI 10.1029/2001JD001149 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 679AC UT WOS:000182898000001 ER PT J AU Wimmers, AJ Moody, JL Browell, EV Hair, JW Grant, WB Butler, CF Fenn, MA Schmidt, CC Li, J Ridley, BA AF Wimmers, AJ Moody, JL Browell, EV Hair, JW Grant, WB Butler, CF Fenn, MA Schmidt, CC Li, J Ridley, BA TI Signatures of tropopause folding in satellite imagery SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tropopause folding; stratosphere-troposphere exchange; water vapor channel; ozone; specific humidity; TOPSE ID STRATOSPHERE-TROPOSPHERE EXCHANGE; ARCTIC AIR-POLLUTION; NORTH-ATLANTIC; OZONE; INTRUSIONS; SYSTEM; LIDAR; DISTRIBUTIONS; TEMPERATURE; RESOLUTION AB A satellite-based conceptual picture of the stratospheric contribution to the spring ozone peak is presented through a survey of flight measurements and satellite imagery from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) program. We address the stratospheric contribution through the process of tropopause folding across air mass boundaries (the arctic and polar tropopause break) in the polar and midlatitude upper troposphere. These boundaries and the boundaries of their related outgrowing streamers are easily identifiable as sharp gradients in the altered water vapor (AWV) imagery, a linear modification of the GOES water vapor channel that represents upper tropospheric specific humidity. The close relationship between altered brightness temperature and total ozone (from the Total Ozone Mapping Spectrometer ( TOMS) and the GOES sounder) along this gradient confirms the utility of AWV imagery in detecting the tropopause break. Transects constructed from aircraft lidar and in situ observations of ozone illustrate the existence of tropopause folding along the AWV gradient. Ten out of ten available transects during the February to May study period show tropopause folding where indicated by the satellite imagery. This is strong evidence that folding is ubiquitous across the polar/stratospheric air mass boundary during the study period, and that the associated intrusions of stratospheric air into the troposphere can be located continuously using AWV imagery. C1 Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. NASA, Lidar Applicat Grp, Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. RP Wimmers, AJ (reprint author), Univ Virginia, Dept Environm Sci, 291 McCormick Rd,POB 400123, Charlottesville, VA 22904 USA. EM wimmers@virginia.edu; moody@virginia.edu; e.v.browell@larc.nasa.gov; j.w.hair@larc.nasa.gov; w.b.grant@larc.nasa.gov; c.f.butler@larc.nasa.gov; m.a.fenn@larc.nasa.gov; chris.schmidt@ssec.wisc.edu; jun.li@ssec.wisc.edu; ridley@ucar.edu RI Grant, William/B-8311-2009; Li, Jun/H-3579-2015 OI Grant, William/0000-0002-1439-3285; Li, Jun/0000-0001-5504-9627 NR 46 TC 20 Z9 20 U1 0 U2 3 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 29 PY 2003 VL 108 IS D4 AR 8360 DI 10.1029/2001JD001358 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 679AA UT WOS:000182897800003 ER PT J AU Sinyuk, A Torres, O Dubovik, O AF Sinyuk, A Torres, O Dubovik, O TI Combined use of satellite and surface observations to infer the imaginary part of refractive index of Saharan dust SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OPTICAL-PROPERTIES; AEROSOL; AERONET; ABSORPTION; NETWORK AB We present a method for the retrieval of the imaginary part of refractive index of desert dust aerosol at near UV wavelengths. The method uses observations of radiances at 331 and 360 nm by the Total Ozone Mapping Spectrometer, and aerosol optical depth measurements by the Aerosol Robotic Network. The derived values of imaginary part of refractive index of Saharan dust aerosol at 360 nm are significantly lower than previously reported values. The average retrieved values vary between 0.0054 and 0.0066 for different geographical locations. The results reported in this work are in good agreement with the results of several recent investigations. C1 Univ Maryland, JCET, College Pk, MD 20742 USA. Univ Maryland, GEST, College Pk, MD 20742 USA. RP Sinyuk, A (reprint author), NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. RI Dubovik, Oleg/A-8235-2009; Torres, Omar/G-4929-2013 OI Dubovik, Oleg/0000-0003-3482-6460; NR 18 TC 92 Z9 92 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 28 PY 2003 VL 30 IS 2 AR 1081 DI 10.1029/2002GL016189 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 678XU UT WOS:000182892600005 ER PT J AU Gonzalez-Esparza, JA Lara, A Perez-Tijerina, E Santillan, A Gopalswamy, N AF Gonzalez-Esparza, JA Lara, A Perez-Tijerina, E Santillan, A Gopalswamy, N TI A numerical study on the acceleration and transit time of coronal mass ejections in the interplanetary medium SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ejecta; CMEs; interplanetary; numerical simulations ID SOLAR-WIND AB [1] Recently, an empirical model of the acceleration/deceleration of coronal mass ejections (CMEs) as they propagate through the solar wind was developed using near-Sun (coronagraphic) and near-Earth ( in situ) observations [Gopalswamy et al., 2000, 2001a]. This model states and quantifies the fact that slow CMEs are accelerated and fast CMEs are decelerated toward the ambient solar wind speed (similar to400 km/s). In this work we study the propagation of CMEs from near the Sun (0.083 AU) to 1 AU using numerical simulations and compare the results with those of the empirical model. This is a parametric study of CME-like disturbances in the solar wind using a one-dimensional, hydrodynamic single-fluid model. Simulated CMEs are propagated through a variable ambient solar wind and their 1 AU characteristics are derived to compare with observations and the empirical CME arrival model. We were able to reproduce the general characteristics of the prediction model and to obtain reasonable agreement with two-point measurements from spacecraft. Our results also show that the dynamical evolution of fast CMEs has three phases: ( 1) an abrupt and strong deceleration just after their injection against the ambient wind, which ceases before 0.1 AU, followed by ( 2) a constant speed propagation until about 0.45 AU, and, finally, ( 3) a gradual and small deceleration that continues beyond 1 AU. The results show that it is somewhat difficult to predict the arrival time of slow CMEs ( V-cme < 400 km/s) probably because the travel time depends not only on the CME initial speed but also on the characteristics of the ambient solar wind and CMEs. However, the simulations show that the arrival time of very fast CMEs (V-cme > 1000 km/s) has a smaller dispersion so the prediction can be more accurate. C1 Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. Univ Nacl Autonoma Mexico, Computo Aplicado DGSCA, Mexico City 04510, DF, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Ctr Solar Phys & Space Weather, Washington, DC 20064 USA. RP Gonzalez-Esparza, JA (reprint author), Univ Nacl Autonoma Mexico, Inst Geofis, Ciudad Univ, Mexico City 04510, DF, Mexico. RI Gopalswamy, Nat/D-3659-2012; Gonzalez-Esparza, J. Americo/A-6720-2013 NR 14 TC 26 Z9 27 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 28 PY 2003 VL 108 IS A1 AR 1039 DI 10.1029/2001JA009186 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 679EN UT WOS:000182907900001 ER PT J AU Liu, XM Shemansky, DE Abgrall, H Roueff, E Ahmed, SM Ajello, JM AF Liu, XM Shemansky, DE Abgrall, H Roueff, E Ahmed, SM Ajello, JM TI Electron impact excitation of H-2: resonance excitation of B (1)Sigma(+)(u)(J(j)=2, v(j)=0) and effective excitation function of EF E-1(g)+ SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID QUANTUM-DEFECT THEORY; MINIMUM 1-SIGMA-G+ STATES; WERNER BAND SYSTEM; MOLECULAR-HYDROGEN; HIGH-RESOLUTION; ULTRAVIOLET EMISSION; TRANSITION MOMENTS; CROSS-SECTIONS; ROVIBRONIC STRUCTURES; DIATOMIC-MOLECULES AB The electron impact emission function of the P(3) branch for the (0, 4) band of the H(2)B(1)Sigma(u)(+)-X(1)Sigma(g)(+) band system has been measured from threshold to 1800 eV. The emission function exhibits structure indicating strong contributions from both resonance and non-resonance excitation. The non-resonance component contains direct and cascade contributions. A combination of experimental and theoretical considerations permits separation of resonance, dipole-allowed direct, dipole-allowed indirect, and dipole-forbidden excitation components for the J(j) = 2, v(j) = 0 level of the B(1)Sigma(u)(+) state. An effective excitation function for the EF (1)Sigma(g)(+)-X(1)Sigma(g)(+) band system has been obtained from a nonlinear least squares analysis of the dipole-forbidden component of the B(1)Sigma(u)(+) state emission function. The absolute value of EF(1)Sigma(g)(+)-X(1)Sigma(g)(+) cross section is established on the basis of earlier experimental results of Liu et al 1995 Astrophys. J. Suppl. 101 375-99 and 2002 Astrophys J. Suppl. 138 229-45 and Abgrall et al 1997 Astrophys. J. 481 557-66 and 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3813-38. A near-threshold apparent resonance excitation cross section of (8.1 +/- 3.2) x 10(-18) cm(2) is obtained for the B (1)Sigma(u)(+) (J(j) = 2 and v(j) = 0). An EF (1)Sigma(g)(+)-X-1 E-g(+) Born cross section has been calculated from the electronic form factor of Kolos et al 1982a J Chem. Phys. 77 1335-44. Analysis shows that the Born asymptotic shape function of the EF (1)Sigma(g)(+)-X (1)Sigma(g)(+) band system starts at similar to400 eV, a significantly higher energy than previously expected. The excitation function is especially important for interpreting outer planet atmospheric dayglow and auroral activity and can be used to infer energy deposition and heating rates. C1 Univ So Calif, Dept Aeronaut & Mech Engn, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Paris, Sect Meudon, F-92195 Meudon, France. DAEC, F-92195 Meudon, France. CNRS UMR 8631, F-92195 Meudon, France. RP Liu, XM (reprint author), Univ So Calif, Dept Aeronaut & Mech Engn, Los Angeles, CA 90089 USA. NR 75 TC 23 Z9 23 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JAN 28 PY 2003 VL 36 IS 2 BP 173 EP 196 AR PII S0953-4075(03)36915-9 DI 10.1088/0953-4075/36/2/301 PG 24 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 642YT UT WOS:000180835500003 ER PT J AU Wilke, CO Adami, C AF Wilke, CO Adami, C TI Evolution of mutational robustness SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE mutation-selection balance; mutational robustness; neutral mutation; quasispecies ID RNA VIRUSES; SEXUAL REPRODUCTION; SELECTION; RATES; HSP90; RECOMBINATION; HETEROGENEITY; EVOLVABILITY; POPULATIONS; SURVIVAL AB We review recent advances in the understanding of the mutation-selection balance of asexual replicators. For over 30 years, population geneticists thought that an expression derived by Kimura and Maruyama in 1966 fully solved this problem. However, Kimura and Maruyama's result is only correct in the absence of neutral mutations. The inclusion of neutral mutations leads to a wealth of interesting new effects, and, in particular, to a selective pressure to evolve robustness against mutations. We cover recent literature on the population dynamics of asexual replicators on networks of neutral genotypes, on the outcompetition of fast replicators by slower ones with better mutational support, and on the probability of fixation at high mutation rates. We discuss empirical evidence for the evolution of mutational robustness, and speculate on its relevance for higher organisms. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, Digital Life Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilke, CO (reprint author), CALTECH, Digital Life Lab, Mail Code 136-93, Pasadena, CA 91125 USA. EM wilke@caltech.edu RI Adami, Christoph/A-5181-2009; Adami, Christoph/A-9675-2011; Wilke, Claus/B-4643-2008 OI Adami, Christoph/0000-0002-2915-9504; Wilke, Claus/0000-0002-7470-9261 NR 53 TC 82 Z9 82 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 EI 1873-135X J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD JAN 28 PY 2003 VL 522 IS 1-2 BP 3 EP 11 AR PII S0027-5107(02)00307-X DI 10.1016/S0027-5107(02)00307-X PG 9 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 642BR UT WOS:000180784900002 PM 12517406 ER PT J AU Li, C Zhang, DH Liu, XL Han, S Tang, T Zhou, CW Fan, W Koehne, J Han, J Meyyappan, M Rawlett, AM Price, DW Tour, JM AF Li, C Zhang, DH Liu, XL Han, S Tang, T Zhou, CW Fan, W Koehne, J Han, J Meyyappan, M Rawlett, AM Price, DW Tour, JM TI Fabrication approach for molecular memory arrays SO APPLIED PHYSICS LETTERS LA English DT Article ID CONDUCTANCE; WIRES AB We present an approach to tackle long-standing problems in contacts, thermal damage, pinhole induced short circuits and interconnects in molecular electronic device fabrication and integration. Our approach uses metallic nanowires as top electrodes to connect and interconnect molecular wires assembled on electrode arrays in crossbar architectures. Using this simple and reliable approach, we have revealed intriguing memory effects for several different molecular wires, and demonstrated their applications in molecular memory arrays. Our approach has great potential to be used for fast screening of molecular wire candidates and construction of molecular devices. (C) 2003 American Institute of Physics. C1 Univ So Calif, Dept EE Electrophys, Los Angeles, CA 90089 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Rice Univ, Dept Chem, Houston, TX 77005 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77005 USA. Eloret Corp, Sunnyvale, CA 94087 USA. RP Li, C (reprint author), Univ So Calif, Dept EE Electrophys, Los Angeles, CA 90089 USA. RI Tang, Tao/C-8123-2011; Zhou, Chongwu/F-7483-2010; OI Tour, James/0000-0002-8479-9328 NR 13 TC 128 Z9 130 U1 0 U2 8 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 27 PY 2003 VL 82 IS 4 BP 645 EP 647 DI 10.1063/1.1541943 PG 3 WC Physics, Applied SC Physics GA 638GV UT WOS:000180564000054 ER PT J AU Zak, M Kulikov, I AF Zak, M Kulikov, I TI Supersonic effects and shock waves in a Bose-Einstein condensate SO PHYSICS LETTERS A LA English DT Article ID GROUND-STATE; GAS AB An analysis of sub- and supersonic waves as well as a mechanism of transformation of sound waves into shock waves is described. Based upon that, a theoretical possibility of shock wave formation in a high density Bose condensate with strong repulsive interaction is obtained. The speed of shock waves as well as relationships between jumps of velocity and density at the front of surface of discontinuity are-derived. The theory is illustrated by the analytical solution for shock wave propagation in a dense condensate cloud. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Explorat Syst Authon Sec 367, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, Explorat Syst Authon Sec 367, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JAN 27 PY 2003 VL 307 IS 2-3 BP 99 EP 106 DI 10.1016/S0375-9601(02)01669-9 PG 8 WC Physics, Multidisciplinary SC Physics GA 639ZG UT WOS:000180660200003 ER PT J AU Xu, J Bergin, MH Greenwald, R Russell, PB AF Xu, J Bergin, MH Greenwald, R Russell, PB TI Direct aerosol radiative forcing in the Yangtze delta region of China: Observation and model estimation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol; optical depth; single scattering albedo; radiative forcing; Yangtze delta ID TROPICAL INDIAN-OCEAN; MID-ATLANTIC COAST; OPTICAL-PROPERTIES; UNITED-STATES; ATMOSPHERIC ABSORPTION; SUN PHOTOMETRY; BOUNDARY-LAYER; SURFACE; PARAMETERIZATION; SULFATE AB [1] The Yangtze delta region of China is a key agricultural area that experiences relatively high aerosol loadings [Xu et al., 2002]. In order to characterize the aerosol radiative properties and estimate direct aerosol radiative forcing in this region, measurements of the multiwavelength aerosol optical depth, tau(lambda), light scattering coefficient, sigma(sp), and absorption coefficient, sigma(ap), as well as the downward photosynthetically active radiation (400-700 nm), DPAR, were conducted during November 1999 in Linan, China. The direct aerosol radiative forcing for photosynthetically active radiation ( PAR) and total solar radiation (0.2-4.0 mum, TSR) at both the surface and top of atmosphere (TOA) are estimated based on the measurements using two radiative transfer models. The model estimates indicate that the mean cloud-free instantaneous direct aerosol radiative forcing efficiency ( for solar zenith angle < 70 degrees) at the surface for PAR is -73.5 W m(-2), which is in agreement with the value of -74.4 W m(-2) derived directly from the measurements of DPAR and 500 nm aerosol optical depth (tau(500)). On the basis of the measured mean tau(500) of 0.61, and the estimated cloud optical depth and cloud coverage of 5.0 and 50%, respectively, the 24-hr mean direct aerosol radiative forcing at the surface for PAR is estimated to be approximately -11.2 W m(-2). This suggests that the amount of PAR reaching the surface over the Yangtze delta region is reduced by similar to 16% as a result of the direct radiative effect of aerosols. The model results also indicate that the cloud-free 24-hr average direct aerosol radiative forcing efficiency at the TOA for TSR is -30.4 W m(-2). When the presence of clouds is considered, the mean direct aerosol radiative forcing at the TOA for TSR is estimated to be approximately -12.1 W m(-2). This value is roughly an order of magnitude greater than the estimated global mean aerosol radiative forcing of -0.3 to -1.0 W m(-2) suggested by the Intergovernmental Panel on Climate Change [ 1996]. Overall, this study indicates that aerosols have a substantial impact on the amount of radiation reaching the surface as well as the radiation balance at the TOA in the Yangtze delta region. C1 Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Xu, J (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, 200 Bobby Dodd Way, Atlanta, GA 30332 USA. EM jin.xu@ce.gatech.edu; mike.bergin@ce.gatech.edu; roby.greenwald@ce.gatech.edu; prussell@mail.arc.nasa.gov NR 56 TC 36 Z9 43 U1 0 U2 6 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 25 PY 2003 VL 108 IS D2 AR 4060 DI 10.1029/2002JD002550 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 660GB UT WOS:000181824500006 ER PT J AU Ogawa, K Schmugge, T Jacob, F French, A AF Ogawa, K Schmugge, T Jacob, F French, A TI Estimation of land surface window (8-12 mu m) emissivity from multispectral thermal infrared remote sensing - A case study in a part of Sahara Desert SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID REFLECTION RADIOMETER ASTER AB [1] Land surface window emissivity is an important parameter for estimating the longwave radiative budget. This study focuses on estimating the window (8-12 mum) emissivity from the waveband emissivities of the five thermal infrared channels of the Advanced Spaceborne Thermal Emission and Reflection Radiometer ( ASTER). ASTER data along with the Temperature-Emissivity Separation (TES) algorithm allows us to estimate surface channel emissivities with 90 m spatial resolution globally. Multiple regression was used to relate window emissivity to the five ASTER emissivities. This regression was developed using spectral libraries. Its residual error was less than 0.005 (RMSE) for values ranging between 0.81 and 1.00. We applied this regression to ASTER emissivities extracted from data acquired in 2001 and 2002 over a 240 x 1200 km area in a desert of North Africa. A comparison against a classification based emissivity map showed significant differences ranging between -0.08 and + 0.06. C1 USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Ogawa, K (reprint author), USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. RI Ogawa, Kenta/B-7687-2008; Jacob, Frederic/A-5946-2011 OI Jacob, Frederic/0000-0002-2491-3096 NR 10 TC 48 Z9 52 U1 0 U2 6 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 24 PY 2003 VL 30 IS 2 AR 1067 DI 10.1029/2002GL016354 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 660EV UT WOS:000181821600006 ER PT J AU Yang, RH Cohn, SE da Silva, A Joiner, J Houser, PR AF Yang, RH Cohn, SE da Silva, A Joiner, J Houser, PR TI Tangent linear analysis of the Mosaic land surface model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tangent linear analysis; land surface state variability; soil moisture dynamics ID RIVER BASIN EXPERIMENT; SIMPLE BIOSPHERE MODEL; PARAMETERIZATION SCHEMES; ATMOSPHERE INTERACTION; SOIL-MOISTURE; PROJECT; VARIABILITY; SIMULATIONS; SENSITIVITY; FLUXES AB [1] In this study, a tangent linear eigenanalysis is applied to the Mosaic land surface model (LSM) [Koster and Suarez, 1992] to examine the impacts of the model internal dynamics and physics on the land surface state variability. The tangent linear model (TLM) of the Mosaic LSM is derived numerically for two sets of basic states and two tile types of land condition, grass and bare soil. An additional TLM, for the soil moisture subsystem of this LSM, is derived analytically for the same cases to obtain explicit expressions for the eigenvalues. An eigenvalue of the TLM determines a characteristic timescale, and the corresponding eigenvector, or mode, describes a particular coupling among the perturbed states. The results show that ( 1) errors in initial conditions tend to decay with e-folding times given by the characteristic timescales; ( 2) the LSM exhibits a wide range of internal variability, modes mainly representing surface temperature and surface moisture perturbations exhibit short timescales, whereas modes mainly representing deep soil temperature perturbations and moisture transfer throughout the entire soil column exhibit much longer timescales; ( 3) the modes of soil moisture tend to be weakly coupled with other perturbed variables, and the mode representing the deep soil temperature perturbation has a consistent e-folding time across the experiments; ( 4) the key parameters include soil moisture, soil layer depth, and soil hydraulic parameters. The results agree qualitatively with previous findings. However, tangent linear eigenanalysis provides a new approach to the quantitative substantiation of those findings. Also, it reveals the evolution and the coupling of the perturbed land states that are useful for the development of land surface data assimilation schemes. One must be careful when generalizing the quantitative results since they are obtained with respect to two specific basic states and two simple land conditions. Also, the methodology employed here does not apply directly to an actual time-varying basic state. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Yang, RH (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. EM ryang@dao.gsfc.nasa.gov RI Joiner, Joanna/D-6264-2012; da Silva, Arlindo/D-6301-2012; Cohn, Stephen/K-1954-2012; Houser, Paul/J-9515-2013 OI da Silva, Arlindo/0000-0002-3381-4030; Cohn, Stephen/0000-0001-8506-9354; Houser, Paul/0000-0002-2991-0441 NR 27 TC 0 Z9 1 U1 0 U2 3 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 2003 VL 108 IS D2 AR 4054 DI 10.1029/2002JD002410 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 660GA UT WOS:000181824400003 ER PT J AU Sanderson, TR Appourchaux, T Hoeksema, JT Harvey, KL AF Sanderson, TR Appourchaux, T Hoeksema, JT Harvey, KL TI Observations of the Sun's magnetic field during the recent solar maximum SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE current sheet; source surface; Sun's dipole; Sun's quadrupole; coronal holes; solar maximum ID HELIOSPHERIC CURRENT SHEET; INTERACTION REGIONS; CORONAL HOLES; ULYSSES; WIND; SOUTH AB [1] We present new observations and analyses of the Sun's magnetic field and coronal holes. Using magnetic field observations from the Wilcox Solar Observatory, we present a simple means whereby the tilt angle of the current sheet can be calculated. We use a data set covering the last 26 years, which shows for the first time how the dipole component rotated once during a full 22-year solar cycle. We show how this influenced the current sheet. At solar minimum, the Sun's coronal magnetic field was essentially dipolar and aligned parallel to the spin axis. As a result, the heliospheric current sheet was flat and had very little warp. Around solar maximum, the dipole was perpendicular to the spin axis, and the ratio of quadrupole to dipole strength was high for much of the time. This meant that the current sheet was tilted and highly warped, and reached up to high latitudes. Surprisingly, there were also times close to solar maximum when the quadrupole/dipole ratio was low, and the current sheet was relatively flat, but still highly inclined. We apply for the first time to solar magnetic data a method, which quantitatively analyses the quadrupole component of the magnetic field. From the terms of the expansion of the observed photospheric magnetic field, we compute the position of the poles of the magnetic field. We combine for the first time over an extended period of time magnetic field data from the Wilcox Solar Observatory with coronal hole positions taken from the National Solar Observatory/Kitt Peak. We find that the position of the coronal holes followed the motion of the poles of the magnetic field as the poles moved over the surface of the Sun and that the polar coronal holes broke up into groups of smaller like-polarity holes as the poles approached the midlatitude regions and the quadrupole became more important. We discuss the implications for energetic particle observations at Ulysses. C1 European Space Agcy, Estec, Dept Space Sci, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. NASA Headquarters, Off Space Sci, Sun Earth Connect Div, Washington, DC 20546 USA. Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. Solar Phys Res Corp, Tucson, AZ USA. RP Sanderson, TR (reprint author), European Space Agcy, Estec, Dept Space Sci, Res & Sci Support Dept, Keplerlaan 1, NL-2200 AG Noordwijk, Netherlands. NR 28 TC 25 Z9 25 U1 0 U2 0 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 24 PY 2003 VL 108 IS A1 AR 1035 DI 10.1029/2002JA009388 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 660KJ UT WOS:000181832100001 ER PT J AU Polyansky, OL Csaszar, AG Shirin, SV Zobov, NF Barletta, P Tennyson, J Schwenke, DW Knowles, PJ AF Polyansky, OL Csaszar, AG Shirin, SV Zobov, NF Barletta, P Tennyson, J Schwenke, DW Knowles, PJ TI High-accuracy ab initio rotation-vibration transitions for water SO SCIENCE LA English DT Article ID POTENTIAL-ENERGY SURFACE; BORN-OPPENHEIMER APPROXIMATION; BASIS-SET CONVERGENCE; RELATIVISTIC CORRECTIONS; SPECTROSCOPIC ACCURACY; WAVE-FUNCTIONS; MOLECULE; LIMIT; H-3(+) AB The spectrum of water vapor is of fundamental importance for a variety of processes, including the absorption and retention of sunlight in Earth's atmosphere. Therefore, there has long been an urgent need for a robust and accurate predictive model for this spectrum. In our work on the high-resolution spectrum of water, we report first-principles calculations that approach experimental accuracy. To achieve this, we performed exceptionally large electronic structure calculations and considered a variety of effects, including quantum electrodynamics, which have routinely been neglected in studies of small many-electron molecules. The high accuracy of the resulting ab initio procedure is demonstrated for the main isotopomers of water. C1 UCL, Dept Phys & Astron, London WC1E 6BT, England. Eotvos Lorand Univ, Dept Theoret Chem, H-1518 Budapest 112, Hungary. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603950, Russia. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Birmingham, Sch Chem Sci, Birmingham B15 2TT, W Midlands, England. RP Tennyson, J (reprint author), UCL, Dept Phys & Astron, Gower St, London WC1E 6BT, England. EM j.tennyson@ucl.ac.uk RI Knowles, Peter/G-2985-2010; Csaszar, Attila/A-5241-2009; Tennyson, Jonathan/I-2222-2012; schwenke, david/I-3564-2013 OI Knowles, Peter/0000-0003-4657-6331; Tennyson, Jonathan/0000-0002-4994-5238; NR 29 TC 225 Z9 227 U1 7 U2 63 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 24 PY 2003 VL 299 IS 5606 BP 539 EP 542 DI 10.1126/science.1079558 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 638EZ UT WOS:000180559800041 PM 12543967 ER PT J AU Ginoux, P AF Ginoux, P TI Effects of nonsphericity on mineral dust modeling SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust; settling; sedimentation; nonsphericity; global model ID AEROSOL OPTICAL-PROPERTIES; SKY RADIANCE MEASUREMENTS; SAHARAN DUST; GOCART MODEL; PARTICLES; CLOUDS; SUN; DISTRIBUTIONS; THICKNESS; SATELLITE AB [1] The dependency of nonsphericity on gravitational settling of mineral dust particles is parameterized for prolate ellipsoids and Reynolds number lower than 2. The settling speed is numerically solved from the momentum equation as a function of particle diameter and aspect ratio. The reduction of settling speed due to nonsphericity is included in the Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model to simulate dust size distribution for April 2001. Two numerical schemes for solving sedimentation are compared. For particles of diameter greater than 5 mum, the simulated size distribution is sensitive to the numerical sedimentation scheme. Changing the particle shape from spherical to nonspherical with lambda = 2 makes little difference to the simulated surface concentration and size distribution except at the periphery of the dust sources. However, when very elongated particles ( lambda = 5) are simulated, the differences between nonspherical and spherical particles are significant. With limited in situ measurements reporting most frequent lambda around 1.5, the overall effects on global modeling is rather negligible and the essential benefit is to relax the CFL condition of Eulerian settling schemes. C1 Univ Maryland Baltimore Cty, Catonsville, MD USA. RP Ginoux, P (reprint author), NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. EM ginoux@rondo.gsfc.nasa.gov RI Ginoux, Paul/C-2326-2008 OI Ginoux, Paul/0000-0003-3642-2988 NR 31 TC 30 Z9 30 U1 1 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 23 PY 2003 VL 108 IS D2 AR 4052 DI 10.1029/2002JD002516 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 660FU UT WOS:000181823800001 ER PT J AU Kabir, HRH Al-Khaleefi, AM Chaudhuri, RA AF Kabir, HRH Al-Khaleefi, AM Chaudhuri, RA TI Frequency response of a moderately thick antisymmetric cross-ply cylindrical panel using mixed type of Fourier solution functions SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID DOUBLY-CURVED PANELS; SHALLOW SHELL THEORIES; FREE-VIBRATION AB A hitherto unavailable analytical solution to the boundary-value problem of the free vibration response of shear-flexible antisymmetric cross-ply laminated cylindrical panels is presented. The laminated shell theory formulation is based on the first order shear deformation theory (FSDT) including rotatory and surface-parallel inertias. The governing equations of the panel are defined by five highly coupled partial differential equations in five unknowns-three displacements, and two rotations. The assumed solution functions for the eigen/boundary-value problem are selected in terms of mixed-type double Fourier series. Numerical results presented for parametric effects, such as length-to-thickness ratio and radius-to-thickness ratio, should serve as a bench mark for future comparison. A four-node shear-flexible finite element is selected to compare the results with the present solution. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Kennedy Space Ctr, Engn & Anal Div, Cape Canaveral, FL 32920 USA. Kuwait Univ, Dept Civil Engn, Safat 13060, Kuwait. Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA. RP Kabir, HRH (reprint author), NASA, Kennedy Space Ctr, Engn & Anal Div, Cape Canaveral, FL 32920 USA. NR 16 TC 16 Z9 16 U1 1 U2 1 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 23 PY 2003 VL 259 IS 4 BP 809 EP 828 DI 10.1006/jsvi.2002.5123 PG 20 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 639YX UT WOS:000180658900005 ER PT J AU Reichhardt, T AF Reichhardt, T TI Balloon-based astronomy: Up, up and away SO NATURE LA English DT News Item C1 NASA, Balloon Program Off, Washington, DC 20546 USA. RP Reichhardt, T (reprint author), NASA, Balloon Program Off, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 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 23 PY 2003 VL 421 IS 6921 BP 308 EP 309 DI 10.1038/421308a PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 637UW UT WOS:000180533000013 PM 12540870 ER PT J AU Smialek, JL AF Smialek, JL TI A deterministic interfacial cyclic oxidation spalling model SO ACTA MATERIALIA LA English DT Article DE thermal cycling; oxidation; modeling; kinetics; nickel alloys ID OXIDE LAYERS; BEHAVIOR; STRESS; SCALES; COSP AB A series summation has been developed to model the iterative scale growth and spalling process of cyclic oxidation. Parabolic scale growth has been assumed. Interfacial spallation of a constant area fraction was stipulated to occur only at the thickest portions. Inputs are the parabolic growth rate constant, spall area fraction, oxide stoichiometry, and cycle duration. Outputs include the net weight change, amount of oxygen and metal consumed, and amount of oxide spalled. Classic weight change curves are produced with an initial maximum and final linear weight loss rate. This simplicity allowed for representation by explicit algebraic functions for all outputs and characteristic features. The maximum in weight change varies directly with the parabolic rate constant and cycle duration and inversely with the spall fraction, all to the 1/2 power. The ratio of the number of cycles to reach maximum and zero weight change is exactly 1:3, and these vary only with the inverse of the spall fraction. Many similarities to and some differences with previous cyclic models are identified. Published by Elsevier Science Ltd on behalf of Acta Materialia. C1 NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, Div Mat, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM james.l.smialek@grs.nasa.gov NR 19 TC 28 Z9 28 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD JAN 22 PY 2003 VL 51 IS 2 BP 469 EP 483 DI 10.1016/S1359-6454(02)00430-5 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 643CR UT WOS:000180844800015 ER PT J AU Work, TM Balazs, GH Wolcott, M Morris, R AF Work, TM Balazs, GH Wolcott, M Morris, R TI Bacteraemia in free-ranging Hawaiian green turtles Chelonia mydas with fibropapillomatosis SO DISEASES OF AQUATIC ORGANISMS LA English DT Article DE bacteria; bacteraemia; Chelonia mydas; green turtle; haematology; Vibrio ID MARINE TURTLES; VIBRIO-HARVEYI; NORTHERN AUSTRALIA; ALGINOLYTICUS; INFECTION; DISEASES; ISLANDS; TISSUES; BLOOD AB Past studies of free-ranging green turtles Chelonia mydas with fibropapillomatosis (FP) in Hawaii have shown that animals become immunosuppressed with increasing severity of this disease. Additionally, preliminary clinical examination of moribund turtles with FP revealed that some animals were also bacteraemic. We tested the hypothesis that bacteraemia in sea turtles is associated with the severity of FP. We captured free-ranging green turtles from areas in Hawaii where FP is absent, and areas where FP has been endemic since the late 1950s. Each turtle was given an FP severity score ranging from 0 (no tumours) to 3 (severely affected). A fifth category included turtles that were stranded ashore and moribund with FP. We found that the percentage of turtles with bacteraemia increased with the severity of FP, and that the majority of bacteria cultured were Vibrio spp. Turtles with severe FP were more susceptible to bactaeremia, probably in, part due to immunosuppression. The pattern of bacteraemia in relation to severity of disease strengthens the hypothesis that immunosuppression is a sequel to FP. C1 US Geol Survey, Natl Wildlife Hlth Ctr, Hawaii Field Stn, Honolulu, HI 96850 USA. Natl Marine Fisheries Serv, SW Fisheries Ctr, Honolulu Lab, Honolulu, HI 96822 USA. US Geol Survey, Natl Wildlife Hlth Ctr, Madison, WI 53711 USA. Makai Anim Clin, Kailua, HI 96734 USA. RP Work, TM (reprint author), US Geol Survey, Natl Wildlife Hlth Ctr, Hawaii Field Stn, 300 Ala Moana Blvd,Room 5-231, Honolulu, HI 96850 USA. EM thierry_work@usgs.gov RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 43 TC 32 Z9 34 U1 0 U2 4 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0177-5103 J9 DIS AQUAT ORGAN JI Dis. Aquat. Org. PD JAN 22 PY 2003 VL 53 IS 1 BP 41 EP 46 DI 10.3354/dao053041 PG 6 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 658FT UT WOS:000181711500006 PM 12608567 ER PT J AU Siskind, DE Eckermann, SD McCormack, JP Alexander, MJ Bacmeister, JT AF Siskind, DE Eckermann, SD McCormack, JP Alexander, MJ Bacmeister, JT TI Hemispheric differences in the temperature of the summertime stratosphere and mesosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE mesosphere; stratosphere; gravity waves; polar mesospheric clouds; temperature ID GRAVITY-WAVE; MIDDLE ATMOSPHERE; THERMAL STRUCTURE; MESOPAUSE REGION; 2-DIMENSIONAL MODEL; SEASONAL-VARIATIONS; LOWER THERMOSPHERE; DOWNWARD CONTROL; WATER-VAPOR; MEAN-FLOW AB [1] We study two processes which may govern interhemispheric differences in the temperature of the summertime middle atmosphere. The first is the direct radiative effect arising from the eccentricity of Earth's orbit. The second factor is the difference in gravity-wave filtering due to the hemispheric asymmetries in the summertime mean winds of the troposphere and lower stratosphere. Using two different gravity-wave drag parameterizations and a zonal wind climatology, we find greater gravity wave induced acceleration of the zonal flow in the southern summer lower stratosphere, which leads to weaker gravity wave drag in the southern upper mesosphere. Using a two-dimensional chemical-dynamical model, we evaluate the temperature changes caused by these drag differences and compare them with those caused by direct radiative asymmetry. The radiative asymmetry peaks in the upper stratosphere but is nonnegligible between 20 and 80 km. The dynamical asymmetry has a primary contribution in the upper mesosphere and a secondary contribution in the lower stratosphere. Overall, our results support the idea that poleward of 30degrees the southern middle atmosphere is warmer than the north by 3-8K between 20 and 85 km. As a result, our model suggests that the relative humidity of the northern summer mesopause region is greater than in the south. This implies that mesospheric clouds (PMCs and NLCs) should be more frequent and more extensive in the north than in the south. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Colorado Res Associates, Boulder, CO 80301 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Siskind, DE (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7640,4555 Overlook Ave SW, Washington, DC 20375 USA. EM siskind@uap2.nrl.navy.mil; eckerman@uap2.nrl.navy.mil; mccormack@uap2.nrl.navy.mil; alexand@colorado-research.com; bacmj@janus.gsfc.nasa.gov OI Siskind, David/0000-0003-1394-7730 NR 45 TC 56 Z9 58 U1 0 U2 4 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 22 PY 2003 VL 108 IS D2 AR 4051 DI 10.1029/2002JD002095 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 660FT UT WOS:000181823700001 ER PT J AU Stamnes, K Yan, BH Li, W Stamnes, JJ Tsay, SC AF Stamnes, K Yan, BH Li, W Stamnes, JJ Tsay, SC TI Pitfalls in atmospheric correction of ocean color imagery: how should aerosol optical properties be computed?: reply to comment SO APPLIED OPTICS LA English DT Editorial Material ID SEAWIFS AB Gordon [Appl. Opt. 42, 542 (2003)] argues that use of external rather than internal mixing when aerosol optical properties are computed will not seriously affect atmospheric correction of ocean color imagery, in spite of the fact that top of the atmosphere reflectances computed with the two approaches differ significantly as shown by Yan et al. [Appl. Opt. 41,412 (2002)]. We apply an algorithm for simultaneous retrieval of aerosol optical properties and chlorophyll concentrations to demonstrate that use of the internal-mixing approach leads to atmospheric corrections that differ significantly from those obtained with the more realistic external-mixing approach. For relative humidities of 90% or more, the differences in retrieved aerosol optical properties and chlorophyll concentrations, incurred by application of the internal-mixing approach, become unacceptably large. (C) 2003 Optical Society of America. C1 Stevens Inst Technol, Dept Phys & Engn Phys, Hoboken, NJ 07030 USA. Decis Syst Technol Inc, Rockville, MD 20850 USA. Univ Bergen, Dept Phys, N-5007 Bergen, Norway. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stevens Inst Technol, Dept Phys & Engn Phys, Hoboken, NJ 07030 USA. EM kstamnes@stevens-tech.edu; banghua.yan@noaa.gov RI Tsay, Si-Chee/J-1147-2014 NR 12 TC 6 Z9 6 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 2003 VL 42 IS 3 BP 545 EP 549 DI 10.1364/AO.42.000545 PG 5 WC Optics SC Optics GA 636XV UT WOS:000180483300028 ER PT J AU Bennett, CL Bay, M Halpern, M Hinshaw, G Jackson, C Jarosik, N Kogut, A Limon, M Meyer, SS Page, L Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL AF Bennett, CL Bay, M Halpern, M Hinshaw, G Jackson, C Jarosik, N Kogut, A Limon, M Meyer, SS Page, L Spergel, DN Tucker, GS Wilkinson, DT Wollack, E Wright, EL TI The Microwave Anisotropy Probe mission SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; dark matter; early universe; space vehicles : instruments ID ANGULAR POWER SPECTRUM; SYSTEMATIC-ERROR ANALYSIS; SMALL-SCALE ANISOTROPY; COBE FIRAS INSTRUMENT; SPINNING DUST GRAINS; BACKGROUND-RADIATION; INFLATIONARY UNIVERSE; SKY MAPS; FLAT UNIVERSE; SOURCE COUNTS AB The purpose of the MAP mission is to determine the geometry, content, and evolution of the universe via a 13' full width half-maximum ( FWHM) resolution full-sky map of the temperature anisotropy of the cosmic microwave background radiation with uncorrelated pixel noise, minimal systematic errors, multifrequency observations, and accurate calibration. These attributes were key factors in the success of NASA's Cosmic Background Explorer (COBE) mission, which made a 7degrees FWHM resolution full sky map, discovered temperature anisotropy, and characterized the fluctuations with two parameters, a power spectral index and a primordial amplitude. Following COBE, considerable progress has been made in higher resolution measurements of the temperature anisotropy. With 45 times the sensitivity and 33 times the angular resolution of the COBE mission, MAP will vastly extend our knowledge of cosmology. MAP will measure the physics of the photon-baryon fluid at recombination. From this, MAP measurements will constrain models of structure formation, the geometry of the universe, and inflation. In this paper we present a prelaunch overview of the design and characteristics of the MAP mission. This information will be necessary for a full understanding of the MAP data and results, and will also be of interest to scientists involved in the design of future cosmic microwave background experiments and/or space science missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Jackson & Tull, Washington, DC 20018 USA. Univ British Columbia, Dept Phys, Vancouver, BC V6T 1Z4, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Univ Chicago, Chicago, IL 60637 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Brown Univ, Dept Phys, Providence, RI 02912 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. RP Bennett, CL (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. RI Kogut, Alan/D-6293-2012; Spergel, David/A-4410-2011; Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 100 TC 269 Z9 271 U1 1 U2 7 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 2003 VL 583 IS 1 BP 1 EP 23 DI 10.1086/345346 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NJ UT WOS:000180346800001 ER PT J AU Cohen, JG Lawrence, CR Blandford, RD AF Cohen, JG Lawrence, CR Blandford, RD TI The redshift of the lensed object in the Einstein ring B0218+357 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : distances and redshifts; galaxies : individual (B0218+357); gravitational lensing ID ABSORPTION; GALAXIES; SYSTEM; EVOLUTION; Z=0.685; RADIO AB We present a secure redshift of z = 0.944 +/- 0.002 for the lensed object in the Einstein ring gravitational lens B0218+357 based on five broad emission lines, in good agreement with our preliminary value announced several years ago based solely on the detection of a single emission line. C1 CALTECH, Palomar Observ, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cohen, JG (reprint author), CALTECH, Palomar Observ, Mail Stop 105-24, Pasadena, CA 91125 USA. NR 20 TC 32 Z9 32 U1 1 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 20 PY 2003 VL 583 IS 1 BP 67 EP 69 DI 10.1086/344837 PN 1 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NJ UT WOS:000180346800006 ER PT J AU Gabel, JR Crenshaw, DM Kraemer, SB Brandt, WN George, IM Hamann, FW Kaiser, ME Kaspi, S Kriss, GA Mathur, S Mushotzky, RF Nandra, K Netzer, H Peterson, BM Shields, JC Turner, TJ Zheng, W AF Gabel, JR Crenshaw, DM Kraemer, SB Brandt, WN George, IM Hamann, FW Kaiser, ME Kaspi, S Kriss, GA Mathur, S Mushotzky, RF Nandra, K Netzer, H Peterson, BM Shields, JC Turner, TJ Zheng, W TI The ionized gas and nuclear environment in NGC 3783. II. Averaged Hubble Space Telescope/STIS and Far Ultraviolet Spectroscopic Explorer Spectra SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3783); galaxies : Seyfert; ultraviolet : galaxies ID ACTIVE GALACTIC NUCLEI; X-RAY-ABSORPTION; C-IV ABSORPTION; INTRINSIC ABSORPTION; IMAGING SPECTROGRAPH; ECHELLE OBSERVATIONS; GALAXY NGC-3783; LINES; NGC-4151; VARIABILITY AB We present observations of the intrinsic absorption in the Seyfert 1 galaxy NGC 3783 obtained with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer (FUSE). We have combined 18 STIS and five FUSE observations to obtain a high signal-to-noise ratio averaged spectrum spanning 905-1730 Angstrom. The averaged spectrum reveals absorption in O VI, N V, C IV, N III, C III, and the Lyman lines up to Lyepsilon in the three blueshifted kinematic components previously detected in the STIS spectrum ( at radial velocities of -1320, -724, and -548 km s(-1)). The highest velocity component exhibits absorption in Si IV We also detect metastable C III in this component, indicating a high density in this absorber. No lower ionization lines, i.e., C II and Si II are detected. A weak, fourth absorption component is tentatively detected in the high-ionization lines and Lyalpha and Lybeta at a radial velocity of -1027 km s(-1). The Lyman lines reveal a complex absorption geometry. The strength of the higher order lines indicates that Lyalpha and Lybeta are saturated over much of the resolved profiles in the three strongest absorption components and that, therefore, their observed profiles are determined by the covering factor. We separate the individual covering factors of the continuum and emission-line sources as a function of velocity in each kinematic component using the Lyalpha and Lybeta lines. The covering factor of the broad-line region is found to vary dramatically between the cores of the individual kinematic components, ranging from 0 to 0.84. In addition, we find that the continuum covering factor varies with velocity within the individual kinematic components, decreasing smoothly in the wings of the absorption by at least 60%. Comparison of the effective covering factors derived from the H I results with those determined directly from the doublets reveals that the covering factor of Si IV is less than half that of H I and N V in the high-velocity component. In addition, the FWHMs of N III and Si IV are narrower than those of the higher ionization lines in this component. These results indicate there is substructure within this absorber. We also find evidence for structure in the column density profiles of the high-ionization lines in this component. We derive a lower limit on the total column (N(H)greater than or equal to10(19) cm(-2)) and ionization parameter (Ugreater than or equal to0.005) in the low-ionization subcomponent of this absorber. The metastable-to-total C III column density ratio implies n(e)approximate to10(9)cm(-3) and an upper limit on the distance of the absorber from the ionizing continuum of Rless than or equal to8x10(17). The decreasing covering factor found in the wings of the absorption and the extreme compactness of the C III* absorber are suggestive of a clumpy absorption gas with a low volume filling factor. C1 Catholic Univ Amer, Inst Astrophys & Computat Sci, NASA,Lab Astron & Solar Phys, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Dept Phys, Baltimore, MD 21250 USA. Univ Florida, Dept Astron, Bryant Space Sci Ctr 211, Gainesville, FL 32611 USA. Johns Hopkins Univ, Dept Phys & Astron, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Tel Aviv Univ, Sch Phys & Astron, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Ohio State Univ, Dept Astron, Baltimore, MD 21218 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. Ohio Univ, Dept Phys & Astron, Clippinger Res Labs, Athens, OH 45701 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Gabel, JR (reprint author), Catholic Univ Amer, Inst Astrophys & Computat Sci, NASA,Lab Astron & Solar Phys, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. RI Brandt, William/N-2844-2015 OI Brandt, William/0000-0002-0167-2453 NR 38 TC 65 Z9 65 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 2003 VL 583 IS 1 BP 178 EP 191 DI 10.1086/345096 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NJ UT WOS:000180346800015 ER PT J AU Padoan, P Boldyrev, S Langer, W Nordlund, A AF Padoan, P Boldyrev, S Langer, W Nordlund, A TI Structure function scaling in the Taurus and Perseus molecular cloud complexes SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : clouds; ISM : individual (Perseus Molecular Cloud, Taurus Molecular Cloud); ISM : kinematics and dynamics; radio lines : ISM; turbulence ID FULLY-DEVELOPED TURBULENCE; LOG-POISSON STATISTICS; INTERSTELLAR CLOUDS; FRACTAL STRUCTURE; STAR-FORMATION; HIERARCHICAL STRUCTURE; DARK CLOUDS; MODEL; CASCADE; ORIGIN AB We compute the structure function scaling of the integrated intensity images of two J=1-0 (13)CO maps of Taurus and Perseus. The scaling exponents of the structure functions, normalized to the third order, follow the velocity scaling of supersonic turbulence, suggesting that turbulence plays an important role in the fragmentation of cold interstellar clouds. The data also allow one to verify the validity of the two basic assumptions of the hierarchical symmetry model, originally proposed for the derivation of the velocity structure function scaling. This shows that the same hierarchical symmetry holds for the projected density field of cold interstellar clouds. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Astron Observ, DK-2100 Copenhagen, Denmark. Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark. RP Padoan, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-506, Pasadena, CA 91109 USA. EM padoan@jpl.nasa.gov; aake@astro.ku.dk RI Nordlund, Aake/M-4528-2014; OI Nordlund, Aake/0000-0002-2219-0541; Padoan, Paolo/0000-0002-5055-5800 NR 38 TC 52 Z9 52 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2003 VL 583 IS 1 BP 308 EP 313 DI 10.1086/345351 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NJ UT WOS:000180346800025 ER PT J AU Gudipati, MS Dworkin, JP Chillier, XDF Allamandola, LJ AF Gudipati, MS Dworkin, JP Chillier, XDF Allamandola, LJ TI Luminescence from vacuum-ultraviolet irradiated cosmic ice analogs and residues SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; comets : general; dust, extinction; ISM : molecules; methods : laboratory; molecular data ID INTERSTELLAR DUST; ION IRRADIATION; SOLAR-SYSTEM; COMET HALLEY; AMINO-ACIDS; PHOTOLYSIS; IAPETUS; MOLECULE; SPECTROPHOTOMETRY; FORMALDEHYDE AB Here we report a study of the optical luminescent properties for a variety of vacuum-ultraviolet (VUV) irradiated cosmic ice analogs and the complex organic residues produced. Detailed results are presented for the irradiated, mixed molecular ice: H(2)O : CH(3)OH : NH(3) : CO (100 : 50 : 1 : 1), a realistic representation for an interstellar/precometary ice that reproduces all the salient infrared spectral features associated with interstellar ices. The irradiated ices and the room-temperature residues resulting from this energetic processing have remarkable photoluminescent properties in the visible (520-570 nm). The luminescence dependence on temperature, thermal cycling, and VUV exposure is described. It is suggested that this type of luminescent behavior might be applicable to solar system and interstellar observations and processes for various astronomical objects with an ice heritage. Some examples include grain temperature determination and vaporization rates, nebula radiation balance, albedo values, color analysis, and biomarker identification. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Cologne, Inst Phys Chem, D-50939 Cologne, Germany. Univ Geneva, Dept Chim Phys, CH-1211 Geneva, Switzerland. RP Gudipati, MS (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. EM mgudipati@mail.arc.nasa.gov RI Gudipati, Murthy/F-7575-2011; Dworkin, Jason/C-9417-2012 OI Dworkin, Jason/0000-0002-3961-8997 NR 42 TC 22 Z9 23 U1 0 U2 7 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JAN 20 PY 2003 VL 583 IS 1 BP 514 EP 523 DI 10.1086/345349 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NJ UT WOS:000180346800046 ER PT J AU Holder, J Bond, IH Boyle, PJ Bradbury, SM Buckley, JH Carter-Lewis, DA Cui, W Dowdall, C Duke, C Perez, ID Falcone, A Fegan, DJ Fegan, SJ Finley, JP Fortson, L Gaidos, JA Gibbs, K Gammell, S Hall, J Hall, TA Hillas, AM Horan, D Jordan, M Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krawczynski, H Krennrich, F LeBohec, S Linton, ET Lloyd-Evans, J Moriarty, P Muller, D Nagai, TN Ong, R Page, M Pallassini, R Petry, D Power-Mooney, B Quinn, J Rebillot, P Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Swordy, SP Vassiliev, VV Wakely, SP Walker, G Weekes, TC AF Holder, J Bond, IH Boyle, PJ Bradbury, SM Buckley, JH Carter-Lewis, DA Cui, W Dowdall, C Duke, C Perez, ID Falcone, A Fegan, DJ Fegan, SJ Finley, JP Fortson, L Gaidos, JA Gibbs, K Gammell, S Hall, J Hall, TA Hillas, AM Horan, D Jordan, M Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krawczynski, H Krennrich, F LeBohec, S Linton, ET Lloyd-Evans, J Moriarty, P Muller, D Nagai, TN Ong, R Page, M Pallassini, R Petry, D Power-Mooney, B Quinn, J Rebillot, P Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Swordy, SP Vassiliev, VV Wakely, SP Walker, G Weekes, TC TI Detection of TeV gamma rays from the BL Lacertae object 1ES 1959+650 with the Whipple 10 meter telescope SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (1ES 1959+650); gamma rays : observations ID ACTIVE GALAXY MARKARIAN-421; X-RAY; ENERGY-SPECTRUM; STRONG FLARES; RADIATION; MKN-501; BLAZARS; PHOTONS; SYSTEM AB We present the first strong detection of very high energy gamma-rays from the close (z=0.048) X-ray-selected BL Lacertae object 1ES 1959+650. Observations were made with the Whipple 10 m telescope on Mount Hopkins, Arizona, using the atmospheric Cerenkov imaging technique. The flux between 2002 May and July was highly variable, with a mean of 0.64+/-0.03 times the steady flux from the Crab Nebula and reaching a maximum of 5 crab, with variability on timescales as short as 7 hr. C1 Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Galway Mayo Inst Technol, Sch Sci, Galway, Ireland. Grinnell Coll, Dept Phys, Grinnell, IA 50112 USA. Natl Univ Ireland, Dept Phys, Dublin 4, Ireland. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Univ Utah, High Energy Astrophys Inst, Salt Lake City, UT 84112 USA. Univ Arkansas, Dept Phys & Astron, Little Rock, AR 72204 USA. Depauw Univ, Dept Phys, Greencastle, IN 46135 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Cork Inst Technol, Dept Phys, Cork, Ireland. RP Holder, J (reprint author), Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. RI Hall, Jeter/F-6108-2013; Hall, Jeter/E-9294-2015 NR 55 TC 51 Z9 51 U1 0 U2 3 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 2003 VL 583 IS 1 BP L9 EP L12 DI 10.1086/367816 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634NL UT WOS:000180347000003 ER PT J AU Krafczyk, M Tolke, J Luo, LS AF Krafczyk, M Tolke, J Luo, LS TI Large-eddy simulations with a multiple-relaxation-time LBE model SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 11th International Conference on Discrete simulation of Fluid Dynamics and Soft Condensed Matter CY AUG 05-09, 2002 CL SHANGHAI, PEOPLES R CHINA SP Fudan Univ, Natl Nat Sci Fdn China, Fudan Univ, TD Lee Phys Lab ID NAVIER-STOKES EQUATION; BOLTZMANN METHOD; LATTICE AB We include Smagorinsky's algebraic eddy viscosity approach into the multiple-relaxation-time (MRT) lattice Boltzmann equation (LBE) for large-eddy simulations (LES) of turbulent flows. The main advantage of the MRT-LBE model over the popular lattice BGK model is a significant improvement of numerical stability which leads to a substantial reduction of oscillations in the pressure field, especially for turbulent flow simulations near the numerical stability limit. The MRT-LBE model for LES is validated with a benchmark case of a surface mounted cube in a channel at Re = 40 000. Our preliminary results agree well with experimental data. C1 Tech Univ Carolo Wilhelmina Braunschweig, Inst Computeranwendungen Bauingenieurwesen, D-38106 Braunschweig, Germany. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Krafczyk, M (reprint author), Tech Univ Carolo Wilhelmina Braunschweig, Inst Computeranwendungen Bauingenieurwesen, Pockelstr 3, D-38106 Braunschweig, Germany. RI Toelke, Jonas/A-1531-2009; Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 14 TC 95 Z9 101 U1 1 U2 18 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD JAN 20 PY 2003 VL 17 IS 1-2 BP 33 EP 39 DI 10.1142/S0217979203017059 PG 7 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 652PM UT WOS:000181387600007 ER PT J AU Lallemand, P Luo, LS AF Lallemand, P Luo, LS TI Hybrid finite-difference thermal lattice Boltzmann equation SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 11th International Conference on Discrete simulation of Fluid Dynamics and Soft Condensed Matter CY AUG 05-09, 2002 CL SHANGHAI, PEOPLES R CHINA SP Fudan Univ, Natl Nat Sci Fdn China, Fudan Univ, TD Lee Phys Lab ID RAYLEIGH-BENARD CONVECTION; MACH NUMBER COMBUSTION; MODEL; STABILITY; SCHEME; FLOWS; SIMULATIONS; DISSIPATION; ALGORITHM; ENERGY AB We analyze the acoustic and thermal properties of athermal and thermal lattice Boltzmann equation (LBE) in 2D and show that the numerical instability in the thermal lattice Boltzmann equation (TLBE) is related to the algebraic coupling among different modes of the linearized evolution operator. We propose a hybrid finite-difference (FD) thermal lattice Boltzmann equation (TLBE). The hybrid FD-TLBE scheme is far superior over the existing thermal LBE schemes in terms of numerical stability. We point out that the lattice BGK equation is incompatible with the multiple relaxation time model. C1 Univ Paris 11, Lab ASCI, F-91405 Orsay, France. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Lallemand, P (reprint author), Univ Paris 11, Lab ASCI, Batiment 506, F-91405 Orsay, France. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 36 TC 46 Z9 46 U1 1 U2 18 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD JAN 20 PY 2003 VL 17 IS 1-2 BP 41 EP 47 DI 10.1142/S0217979203017060 PG 7 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 652PM UT WOS:000181387600008 ER PT J AU Markham, BL Barker, JL Kaita, E Seiferth, J Morfitt, R AF Markham, BL Barker, JL Kaita, E Seiferth, J Morfitt, R TI On-orbit performance of the Landsat-7 ETM+ radiometric calibrators SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Conference on Characterization and Radiometric Calibration fo Remote Sensing CY NOV 09-11, 1999 CL UTAH STATE UNIV, LOGAN, UTAH HO UTAH STATE UNIV AB The Landsat-7 Enhanced Thematic Mapper Plus (ETM +) incorporates two new devices to improve its absolute radiometric calibration: a Full Aperture Solar Calibrator (FASC) and a Partial Aperture Solar Calibrator (PASC). The FASC is a diffuser panel, typically deployed once per month. Initial FASC absolute calibration results were within 5% of the pre-launch calibrations. Over time, the responses of the ETM + to the FASC have varied with the location viewed on the panel, suggesting a localized degradation or contamination of the panel. On the best part of the panel, the I rends in response range from -1.4% y(-1) (band 4) to +0.6% y(-1) (band 7), with band 5 showing the least change at -0.4% y(-1). Changes in the panel reflectance due to UV exposure are believed to be the origin of these trends. The PASC is a set of auxiliary optics that allows the ETM + to image the Sun through reduced apertures. PASC data have normally been acquired on a daily basis. Unlike the FASC, the PASC has exhibited significant anomalies. During the first six months of operation, responses to the PASC increased up to 60%, sending bands 2, 3 and 8 into saturation (band I was saturated at launch). The short-wave infrared (SWIR) band individual detectors have shown variations up to +/-20% in response to the PASC. The variation is different for each detector. After the first six months, the responses to the PASC have become more stable, with much of the variation related to the within-scan position of the solar image. Overall results to date for all calibrators and comparisons with vicarious calibrations indicate that most of the response variations have been due to the calibrators themselves and suggest that the instrument has been stable with changes in response of less than 0.5% y(-1). C1 NASA, Goddard Space Flight Ctr, Landstat Sci Off, Greenbelt, MD 20771 USA. SSAI Inc, Goddard Space Flight Ctr, Landstat Sci Off, Greenbelt, MD 20771 USA. RITSS Inc, Goddard Space Flight Ctr, Landstat Sci Off, Greenbelt, MD 20771 USA. RITSS Inc, EROS Data Ctr, Sioux Falls, SD 57198 USA. RP Markham, BL (reprint author), NASA, Goddard Space Flight Ctr, Landstat Sci Off, Greenbelt, MD 20771 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 4 TC 23 Z9 25 U1 1 U2 5 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 2003 VL 24 IS 2 BP 265 EP 285 DI 10.1080/01431160110113179 PG 21 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 640YV UT WOS:000180717400007 ER PT J AU Huang, LK Cebula, RP Taylor, SL Deland, MT McPeters, RD Stolarski, RS AF Huang, LK Cebula, RP Taylor, SL Deland, MT McPeters, RD Stolarski, RS TI Determination of NOAA-11 SBUV/2 radiance sensitivity drift based on measurements of polar ice cap radiance SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Conference on Characterization and Radiometric Calibration fo Remote Sensing CY NOV 09-11, 1999 CL UTAH STATE UNIV, LOGAN, UTAH HO UTAH STATE UNIV ID SOLAR BACKSCATTER ULTRAVIOLET; OZONE RETRIEVAL; BUV INSTRUMENT; CALIBRATION; SATELLITE; NIMBUS-4; IMPACT AB The Solar Backscattered Ultraviolet model 2 (SBUV/2) instrument on the National Oceanic and Atmospheric Administration (NOAA-11) satellite has measured global total ozone and its altitude profile in the stratosphere since 1989. For the ozone measurement, its monochromator scans 12 discrete wavelengths from 252-340 nm. An onboard calibration system malfunctioned in late 1994. This necessitated the development of alternative methods of characterizing sensor sensitivity change. Assuming that the seasonal variation of surface reflectivity is the same from year to year, we used radiance measurements at 340 nm over the polar snow and ice to determine long-term instrument sensitivity drift at 340 nm. The spectral dependence of sensor sensitivity change in 1993 was used as an initial estimate for the current calibration. We then refined the calibration at 313, 318 and 331 run for the total ozone retrieval, using the D-pair validation analysis. The estimated uncertainty in the extended calibration is less than 1%. The updated calibration has been used for NOAA-11 SBUV/2 operation. The resulting NOAA-11 SBUV/2 total ozone data were compared with ozone data from the Earth Probe Total Ozone Mapping Spectrometers (TOMS). The two agree with each other to better than 2%. C1 SSAI, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Huang, LK (reprint author), SSAI, 10210 Greenbelt Rd, Lanham, MD 20706 USA. RI Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013 OI Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462 NR 23 TC 5 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 2003 VL 24 IS 2 BP 305 EP 314 DI 10.1080/01431160110113133 PG 10 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 640YV UT WOS:000180717400009 ER PT J AU Taylor, SL Cebula, RP Deland, MT Huang, LK Stolarski, RS McPeters, RD AF Taylor, SL Cebula, RP Deland, MT Huang, LK Stolarski, RS McPeters, RD TI Improved calibration of NOAA-9 and NOAA-11 SBUV/2 total ozone data using in-flight validation methods SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Conference on Characterization and Radiometric Calibration fo Remote Sensing CY NOV 09-11, 1999 CL UTAH STATE UNIV, LOGAN, UTAH HO UTAH STATE UNIV AB The Solar Backscattered Ultraviolet (SBUV)/2 instrument on-board the National Oceanic and Atmospheric Administration (NOAA)-9 satellite monitored global total ozone and its vertical distribution from 1985 to 1998. The instrument's diffuser reflectivity calibration system failed early in the mission and an alternative calibration procedure with a time extrapolation was used for an initial processing (Version 6.1 data). The total ozone data shows a +3% drift from 1992 to 1998 as well as large seasonal variations with respect to ground based and other satellite data. Using two internal data validation techniques the total ozone data quality is significantly improved. One method, the 'D-pair Method', which is analogous to the method used for the Nimbus 7 SBUV, corrects the diffuser reflectivity calibration and eliminates the drift in total ozone for NOAA-9. The D-pair Method applied to NOAA-11 SBUV/2 data from 1989 to 1994 shows good agreement with the NOAA-11 on-board diffuser reflectivity calibration system. The second validation method, the 'PMT System Method', is a new method that corrects the Photomultiplier Tube System Nonlinearity Characterization in Range 3 thereby reducing the seasonal variation in total ozone. The PMT System Method corrects both the NOAA-9 and NOAA-11 data. C1 SESDA Program Off, Lanham, MD 20710 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Taylor, SL (reprint author), SESDA Program Off, Aerosp Bldg,10210 Greenbelt Rd,Suite 500, Lanham, MD 20710 USA. RI Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013 OI Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462 NR 11 TC 6 Z9 6 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 2003 VL 24 IS 2 BP 315 EP 328 DI 10.1080/0143116021000018282 PG 14 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 640YV UT WOS:000180717400010 ER PT J AU Jaross, G Taylor, SL Wellemeyer, CG Cebula, RP Huang, LK Stolarski, RS McPeters, RD AF Jaross, G Taylor, SL Wellemeyer, CG Cebula, RP Huang, LK Stolarski, RS McPeters, RD TI An assessment of long-term ozone trend uncertainties using Total Ozone Mapping Spectrometers (TOMS) SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Conference on Characterization and Radiometric Calibration fo Remote Sensing CY NOV 09-11, 1999 CL UTAH STATE UNIV, LOGAN, UTAH HO UTAH STATE UNIV ID DATA SET; CALIBRATION AB We provide here an estimate of the uncertainties that would result when combining multiple Total Ozone Mapping Spectrometer (TOMS) datasets to produce a long-term column ozone record. We use calibration results and various post-launch validations to estimate calibration-related uncertainties for each of the instruments. Two basic methods for combining the individual data records are examined. We assess the combined uncertainty in the global column ozone data record for the period 1978-2000 for both methods using a Monte Carlo model with basic Gaussian statistics. In the case where TOMS data are combined without relative adjustments we estimate a trend uncertainty of slightly less than 1% per decade in the column ozone time dependence. The recently re-calibrated Solar Backscattered Ultraviolet 2 (SBUV2) datasets can be utilized to bridge a gap between TOMS datasets that occurred in the mid-1990s. With our current understanding of the sensor comparisons, we estimate a small improvement in the combined TOMS trend uncertainty. A more significant improvement comes from considering an extended TOMS data record, out to 2007. We estimate an extended ozone trend uncertainty as low as 0.5% per decade. C1 Raytheon ITSS, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Jaross, G (reprint author), Sci Syst & Applicat Inc, 10210 Greenbelt Rd, Lanham, MD 20706 USA. RI Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013 OI Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462 NR 14 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 2003 VL 24 IS 2 BP 329 EP 338 DI 10.1080/01431160110113124 PG 10 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 640YV UT WOS:000180717400011 ER PT J AU Tansock, JJ Hansen, S Paskett, K Shumway, A Peterson, J Stauder, J Gordley, LL Wang, Y Melbert, M Russell, JM Mlynczak, MG AF Tansock, JJ Hansen, S Paskett, K Shumway, A Peterson, J Stauder, J Gordley, LL Wang, Y Melbert, M Russell, JM Mlynczak, MG TI SABER ground calibration SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Conference on Characterization and Radiometric Calibration fo Remote Sensing CY NOV 09-11, 1999 CL UTAH STATE UNIV, LOGAN, UTAH HO UTAH STATE UNIV AB This paper describes ground calibration of a 10-channel infrared (1.27-17 mum wavelength) radiometer instrument known as sounding of the atmosphere using broadband emission radiometry (SABER). SABER is one of four experiments that will fly on the thermosphere, ionosphere, mesosphere, energetics and dynamics (TIMED) mission to be launched in 2001. SABER will be used to measure atmospheric infrared emissions from the earthlimb. Ground calibration testing was completed in September 1999. Subsequent data analyses and report generation was completed in June 2000. This paper provides an overview of the instrument design, calibration approach, calibration equation and radiometric model. It also describes the SABER ground calibration facility, survey of calibration results and calibration radiance uncertainty. C1 Utah State Univ, Space Dynam Lab, Logan, UT 84341 USA. GATS Inc, Newport News, VA 23606 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Tansock, JJ (reprint author), Utah State Univ, Space Dynam Lab, 1695 N Res Pkwy, Logan, UT 84341 USA. RI Mlynczak, Martin/K-3396-2012 NR 11 TC 4 Z9 4 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 20 PY 2003 VL 24 IS 2 BP 403 EP 420 DI 10.1080/01431160110113106 PG 18 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 640YV UT WOS:000180717400016 ER PT J AU Lallemand, P Luo, LS AF Lallemand, P Luo, LS TI Lattice Boltzmann method for moving boundaries SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE generalized lattice Boltzmann equation; moving boundary; Galilean invariance; flows past an impulsively started cylinder moving in a channel ID NAVIER-STOKES EQUATION; PARTICULATE SUSPENSIONS; NUMERICAL SIMULATIONS; ANALYTIC SOLUTIONS; CIRCULAR-CYLINDER; NONIDEAL GASES; SIMPLE FLOWS; MODELS; DERIVATION; SYSTEM AB We propose a lattice Boltzmann method to treat moving boundary problems for solid objects moving in a fluid. The method is based on the simple bounce-back boundary scheme and interpolations. The proposed method is tested in two flows past an impulsively started cylinder moving in a channel in two dimensions: (a) the flow past an impulsively started cylinder moving in a transient Couette flow; and (b) the flow past an impulsively started cylinder moving in a channel flow at rest. We obtain satisfactory results and also verify the Galilean invariance of the lattice Boltzmann method. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Paris 11, Lab CNRS ASCI, F-91405 Orsay, France. RP Luo, LS (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C,3 W Reid St,Bldg 1152, Hampton, VA 23681 USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 30 TC 235 Z9 245 U1 4 U2 36 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 JAN 20 PY 2003 VL 184 IS 2 BP 406 EP 421 AR PII S0021-9991(02)00022-0 DI 10.1016/S0021-9991(02)00022-0 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 652WA UT WOS:000181402800004 ER PT J AU King, JC Comiso, JC AF King, JC Comiso, JC TI The spatial coherence of interannual temperature variations in the Antarctic Peninsula SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VARIABILITY AB [1] The west coast of the Antarctic Peninsula is a region of extreme interannual variability in near-surface temperatures. Recently the region has also experienced more rapid warming than any other part of the Southern Hemisphere. In this paper we use a new dataset of satellite-derived surface temperatures to define the extent of the region of extreme variability more clearly than was possible using the sparse station data. The region in which satellite surface temperatures correlate strongly with west Peninsula station temperatures is largely confined to the seas just west of the Peninsula. Correlation of Peninsula surface temperatures with those over the rest of continental Antarctica is poor confirming that the west Peninsula is in a different climate regime. Our analysis suggests that only one of five existing ice cores from the region is likely to provide a proxy climate record that is representative of the west coast. C1 British Antarctic Survey, NERC, Cambridge CB3 0ET, England. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP King, JC (reprint author), British Antarctic Survey, NERC, Cambridge CB3 0ET, England. EM jcki@bas.ac.uk; joey@gsfc.nasa.gov NR 8 TC 46 Z9 47 U1 0 U2 5 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 18 PY 2003 VL 30 IS 2 AR 1040 DI 10.1029/2002GL015580 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 655VP UT WOS:000181573600002 ER PT J AU Weimer, DR Ober, DM Maynard, NC Collier, MR McComas, DJ Ness, NF Smith, CW Watermann, J AF Weimer, DR Ober, DM Maynard, NC Collier, MR McComas, DJ Ness, NF Smith, CW Watermann, J TI Predicting interplanetary magnetic field (IMF) propagation delay times using the minimum variance technique SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID SOLAR-WIND AB [1] It has been known that the fluctuations in the interplanetary magnetic field ( IMF) may be oriented in approximately planar structures that are tilted with respect to the solar wind propagation direction along the Sun-Earth line. This tilting causes the IMF propagating from a point of measurement to arrive at other locations with a timing that may be significantly different from what would be expected. The differences between expected and actual arrival times may exceed an hour, and the tilt angles and subsequent delays may have substantial changes in just a few minutes. A consequence of the tilting of phase planes is that predictions of the effects of the IMF at the Earth, on the basis of IMF measurements far upstream in the solar wind, will suffer from reduced accuracy in the timing of events. It has recently been shown how the tilt angles may be determined using multiple satellite measurements. However, since the multiple satellite technique cannot be used with real-time data from a single sentry satellite, then an alternative method is required to derive the phase front angles, which can then be used for more accurate predictions. In this paper we show that the minimum variance analysis (MVA) technique can be used to adequately determine the variable tilt of the plane of propagation. The number of points that is required to compute the variance matrix has been found to be much higher than expected, corresponding to a time period in the range of 7 to 30 min. The optimal parameters for the MVA were determined by a comparison of simultaneous IMF measurements from four satellites. With use of the optimized parameters it is shown that the MVA method performs reasonably well for predicting the actual time lags in the propagation between multiple spacecraft, as well as to the Earth. Application of this technique can correct for errors, on the order of 30 min or more, in the timing of predictions of geomagnetic effects on the ground. C1 Mission Res Corp, Nashua, NH 03062 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SW Res Inst, San Antonio, TX USA. Bartol Res Inst, Newark, DE USA. Danish Meteorol Inst, Copenhagen, Denmark. RP Weimer, DR (reprint author), Mission Res Corp, 589 W Hollis St,Suite 201, Nashua, NH 03062 USA. EM dweimer@mrcnh.com RI Collier, Michael/I-4864-2013 OI Collier, Michael/0000-0001-9658-6605 NR 18 TC 182 Z9 182 U1 1 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 17 PY 2003 VL 108 IS A1 AR 1026 DI 10.1029/2002JA009405 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 659WK UT WOS:000181800300001 ER PT J AU Custaud, MA Arnaud, SB Monk, TH Claustrat, B Gharib, C Gauquelin-Koch, G AF Custaud, MA Arnaud, SB Monk, TH Claustrat, B Gharib, C Gauquelin-Koch, G TI Hormonal changes during 17 days of head-down bed-rest SO LIFE SCIENCES LA English DT Article DE circadian rhythms; human; hormones; head-down bed rest ID CIRCADIAN-RHYTHMS; CATECHOLAMINE EXCRETION; LIGHT EXPOSURE; SELF-RATINGS; SLEEP; MELATONIN; PLASMA; SULFATE; MEN AB We investigated in six men the impact of 17 days of head-down bed rest (HDBR) on the daily rhythms of the hormones involved in hydroelectrolytic regulation. This HDBR study was designed to mimic a real space flight. Urine samples were collected at each voiding before, during and after HDBR. Urinary excretion of Growth Hormone (GH), Cortisol, 6 Sulfatoxymelatonin, Normetadrenaline (NMN) and Metadrenaline (NM) was determined. A decrease in urinary cortisol. excretion during the night of HDBR was noted. For GH, a rhythm was found before and during HDBR. The rhythm of melatonin, evaluated with the urine excretion of 6 Sulfatoxymelatonin (aMT6S), the main hepatic metabolite, persisted throughout the experiment without any modification to the level of phase. A decrease during the night was noted for normetadrenaline urinary derivates, but only during the HDBR. Published by Elsevier Science Inc. C1 Fac Med Lyon Grange Blanche, Lab Physiol Environm, GIP Exercice, F-69373 Lyon 08, France. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Pittsburgh, Sleep & Chronobiol Ctr, Western Psychiat Inst & Clin, Pittsburgh, PA 15213 USA. Hop Neurol, Serv Radioanal Ctr Med Nucl, F-69394 Lyon 03, France. Ctr Natl Etud Spatiales, F-75039 Paris 01, France. RP Custaud, MA (reprint author), Fac Med Lyon Grange Blanche, Lab Physiol Environm, GIP Exercice, 8 Ave Rockefeller, F-69373 Lyon 08, France. RI Custaud, Marc-Antoine/K-1376-2015 NR 30 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0024-3205 J9 LIFE SCI JI Life Sci. PD JAN 17 PY 2003 VL 72 IS 9 BP 1001 EP 1014 AR PII S0024-3205(02)02349-4 DI 10.1016/S0024-3205(02)02349-4 PG 14 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA 637NJ UT WOS:000180518400003 PM 12495779 ER PT J AU Murphy, D Genio, E Ahlers, G Liu, FC Liu, YM AF Murphy, D Genio, E Ahlers, G Liu, FC Liu, YM TI Finite-size scaling and universality of the thermal resistivity of liquid He-4 near T-lambda SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERFLUID TRANSITION; PLANAR GEOMETRY; CONDUCTIVITY; HEAT; GRAVITY AB We present measurements of the thermal resistivity rho(t,P,L) near the superfluid transition of He-4 at saturated vapor pressure and confined in cylindrical geometries with radii L=0.5 and 1.0 mum [tequivalent toT/T-lambda(P)-1]. For L=1.0 mum measurements at six pressures P are presented. At and above T-lambda the data are consistent with a universal scaling function F(X)=(L/xi(0))(x/nu)(rho/rho(0)), X=(L/xi(0))(1/nu)t valid for all P (rho(0) and x are the pressure-dependent amplitude and effective exponent of the bulk resistivity rho, and xi=xi(0)t(-nu) is the correlation length). Indications of breakdown of scaling and universality are observed below T-lambda. C1 Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, iQUEST, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Murphy, D (reprint author), Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. NR 19 TC 11 Z9 11 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 17 PY 2003 VL 90 IS 2 AR 025301 DI 10.1103/PhysRevLett.90.025301 PG 4 WC Physics, Multidisciplinary SC Physics GA 636FP UT WOS:000180444200023 PM 12570552 ER PT J AU Irizarry-Ortiz, MM Wang, GL Eltahir, EAB AF Irizarry-Ortiz, MM Wang, GL Eltahir, EAB TI Role of the biosphere in the mid-Holocene climate of West Africa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE West Africa; Holocene; vegetation dynamics; monsoon; climate change; insolation ID LAKE STATUS DATA; NORTHERN AFRICA; LARGE-SCALE; ATMOSPHERE INTERACTIONS; MODEL SIMULATIONS; ARABIAN PENINSULA; BIOME MODEL; VEGETATION; MIDHOLOCENE; FEEDBACKS AB [1] In previous studies, a zonally symmetric, synchronously coupled biosphere-atmosphere model ( ZonalBAM), which includes explicit representation of ecosystem dynamics, has been developed and validated based on current conditions over the region of West Africa. Here, we use ZonalBAM to study the response of the coupled biosphere-atmosphere system to changes in the Earth's orbital forcing during the Middle Holocene (6K yrs BP) and the relative contribution of vegetation feedbacks. Simulations in which vegetation conditions were fixed to the current distribution, show that an orbitally induced increased seasonality in insolation for the Middle Holocene, by itself, results in a 1.1degrees northward shift in the location of the southern margin of the Sahara as compared to current solar forcings. When vegetation is allowed to be dynamic, a 2.4degrees northward shift is simulated. However, when dynamic vegetation is initialized to palaeovegetation, a 5.1degrees northward shift is simulated, bringing results more consistent with palaeoevidence. Based on previous studies on the role of the gradient of moist static energy on the dynamics of large-scale tropical circulations, a mechanism for the enhancement of the summer monsoon circulation has been developed. Our results suggest that multiple equilibria could have coexisted over the region of West Africa during the Middle Holocene. Furthermore, based on previous studies on the current climate over the region, we hypothesize that transitions between the different equilibria could have taken place during the Middle Holocene causing the southern desert margin to migrate between 18.1degreesN and 21.4degreesN and shaping climate variability. C1 MIT, Ralph M Parsons Lab, Cambridge, MA 02139 USA. NASA, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Greenbelt, MD USA. Univ Maryland, Greenbelt, MD USA. RP Irizarry-Ortiz, MM (reprint author), S Florida Water Management Dist, W Palm Beach, FL USA. EM michelle@boriken.com; gwang@engr.uconn.edu; eltahir@mit.edu NR 40 TC 16 Z9 16 U1 0 U2 1 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 2003 VL 108 IS D2 AR 4042 DI 10.1029/2001JD000989 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 659TN UT WOS:000181793700002 ER PT J AU Kita, NT Mostefaoui, S Liu, YZ Togashi, S Morishita, Y AF Kita, NT Mostefaoui, S Liu, YZ Togashi, S Morishita, Y TI Application of high precision SIMS Al-26-Mg-26 analyses to the early solar system chronology SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 13th International Conference on Secondary Ion Mass Spectrometry and Related Topics (SIMS XIII) CY NOV 11-16, 2001 CL NARA, JAPAN DE SIMS; magnesium; isotope; electron multiplier; multi-collector; Faraday cup ID AL-26; NEBULA AB High precision SIMS Al-26-Mg-26 isotopic analyses were performed in order to detect the excesses of (26)mg that derived from in situ decay of Al-26 (half-life of 0.73 million years) in primitive meteorites. The electron multiplier is used to analyze Mg isotopes in Al-rich glass using 5 mum O-2(-) primary ion beam. The EM dead time correction and Al/Mg sensitivity calibration are applied to obtain accurate data. The precisions of Mg-26/Mg-24 isotopic ratios and Al-27/Mg-24 atomic ratios were 2-5parts per thousand and 10%, respectively. The relative formation time of less than I million years among chondrules is able to be determined. Further attempt was made to improve the precision of Mg isotopic ratios using the multi-collector Faraday cups. The preliminary tests showed both internal and external precisions of better than 0.1parts per thousand. (C) 2002 Elsevier Science B.V. All rights reserved. C1 AIST, Geol Survey Japan, Tsukuba, Ibaraki 3058567, Japan. Max Planck Inst Chem, D-55020 Mainz, Germany. NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Kita, NT (reprint author), AIST, Geol Survey Japan, AIST Tsukuba Cent 7, Tsukuba, Ibaraki 3058567, Japan. RI Togashi, Shigeko/A-8459-2011; Kita, Noriko/H-8035-2016 OI Togashi, Shigeko/0000-0003-3209-4956; Kita, Noriko/0000-0002-0204-0765 NR 6 TC 4 Z9 4 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JAN 15 PY 2003 VL 203 BP 806 EP 809 AR PII S0169-4332(02)00829-2 DI 10.1016/S0169-4332(02)00829-2 PG 4 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 637RT UT WOS:000180527300180 ER PT J AU Houser, JG Farrell, WM Metzger, SM AF Houser, JG Farrell, WM Metzger, SM TI ULF and ELF magnetic activity from a terrestrial dust devil SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MARS AB [1] Terrestrial dust devils are known to be triboelectric generators: electric charge is generated and exchanged via the mixing and colliding of moving grains. Static electric fields from the structures have been previously reported, this in excess of 1/2 kV/m at a couple hundred meters from the devil. In this work, we report on AC magnetic measurements made during the passage of an intense similar to10-m wide, couple hundred-meter tall dust devil in the Nevada desert. The devil-related magnetic activity appears in two forms: Impulsive extremely-low-frequency (ELF: 30-300 Hz) static discharges to the instrument as the sensor became immersed directly into the devil's electrified dust and ultra-low-frequency (ULF: 3-30 Hz), continuous emissions that were sensed remotely as the storm approached and receded from the mobile station. The latter is a new finding not previously reported. Such measurements not only prove that individual dust grains within the devil are charged, but that the grains are transported in bulk to form an extended, coherent radiation source. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Nevada, Reno, NV 89557 USA. RP Houser, JG (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. RI Farrell, William/I-4865-2013 NR 14 TC 18 Z9 18 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 15 PY 2003 VL 30 IS 1 AR 1027 DI 10.1029/2001GL014144 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 655VD UT WOS:000181572600001 ER PT J AU Wang, DY AF Wang, DY TI Quantum dynamics study of the isotopic effect on capture reactions: HD, D-2+CH3 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID H-2 REVERSIBLE CH4+H; H+CH4->H-2+CH3 REACTION; RATE CONSTANTS; DIMENSIONALITY CALCULATIONS; REDUCED DIMENSIONALITY; SHOCK-TUBE; CH4+H->CH3+H-2; H+CH4->CH3+H-2; ABSTRACTION; SCATTERING AB Time-dependent wave-packet-propagation calculations are reported for the isotopic reactions, HD+CH3 and D-2+CH3, in six degrees of freedom and for zero total angular momentum. Initial-state-selected reaction probabilities for different initial rotational-vibrational states are presented in this study. This study shows that excitations of the HD(D-2) enhances the reactivities, whereas the excitations of the CH3 umbrella mode have the opposite effects. This is consistent with the reaction of H-2+CH3. The comparison of these three isotopic reactions also shows the isotopic effects in the initial-state-selected reaction probabilities. The cumulative reaction probabilities (CRPs) are obtained by summing over initial-state-selected reaction probabilities. Theenergy-shift approximation to account for the contribution of degrees of freedom missing in the six dimensionality calculation is employed to obtain approximate full dimensional CRPs. The rate constant comparison shows the H-2+CH3 reaction has the biggest reactivity, then HD+CH3, and D-2+CH3 has the smallest. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Eloret Inst, Moffett Field, CA 94035 USA. RP Wang, DY (reprint author), NASA, Ames Res Ctr, Eloret Inst, Mail Stop T27B-1, Moffett Field, CA 94035 USA. NR 35 TC 18 Z9 18 U1 0 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JAN 15 PY 2003 VL 118 IS 3 BP 1184 EP 1188 DI 10.1063/1.1529178 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 634AB UT WOS:000180316700023 ER PT J AU DiNunno, B Davis, D Chen, G Crawford, J Olson, J Liu, S AF DiNunno, B Davis, D Chen, G Crawford, J Olson, J Liu, S TI An assessment of ozone photochemistry in the central/eastern North Pacific as determined from multiyear airborne field studies SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEM-TROPICS-B; TROPOSPHERIC OZONE; TRANSPORT; PHOTOLYSIS; CHEMISTRY; POLLUTION; AEROSOL; ORIGIN; AIR AB [1] In this study, the photochemistry of ozone is examined for the central/eastern North Pacific (CENP), a region bounded by 180degrees-120degreesW and 0degrees-45degreesN. Measurements of ozone precursors have been made in this region during 10 previous airborne studies covering the last two decades. The two seasons for which the most extensive analysis has been possible are spring (March-May) and fall (September-November). Box model results have been displayed in the form of latitudinal/altitudinal plots for ozone formation, destruction, and net tendency. They indicate that for both seasons of the year, significant net destruction is found for altitudes in the 0-4 km range; whereas, at higher altitudes, the ozone tendency calculations lead to small values of net production. For both seasons, however, the total column integrated ozone trend is one of net destruction. The largest difference between seasons was in the value for ozone destruction. During springtime, this value was significantly larger than for fall. This trend coincides with higher average springtime ozone levels. The trends in CENP ozone were also compared to those for the western Pacific using measurements recorded during PEM-West A (fall 1991) and PEM-West B (spring 1994). While the PEM-West A results revealed a neutral ozone column tendency, those from PEM-West B showed net production at all altitudes. Both results are in sharp contrast to those reported here for the CENP region showing net destruction. This suggests that while lightning and surface emissions of NOx from the northwestern Pacific Rim have a strong influence on the ozone tendency in the surrounding region, due to the combined effects of dispersion and chemical loss most of this NOx does not reach the CENP region. Hence, ozone in the central Pacific is typically destroyed by photochemistry. C1 Georgia Inst Technol, Dept Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Acad Sinica, Inst Earth Sci, Taipei 115, Taiwan. RP DiNunno, B (reprint author), Georgia Inst Technol, Dept Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM bd42@prism.gatech.edu RI Crawford, James/L-6632-2013 OI Crawford, James/0000-0002-6982-0934 NR 45 TC 4 Z9 4 U1 0 U2 2 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 15 PY 2003 VL 108 IS D2 AR 8237 DI 10.1029/2001JD001468 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 659TL UT WOS:000181793500003 ER PT J AU Hutterli, MA McConnell, JR Bales, RC Stewart, RW AF Hutterli, MA McConnell, JR Bales, RC Stewart, RW TI Sensitivity of hydrogen peroxide (H2O2) and formaldehyde (HCHO) preservation in snow to changing environmental conditions: Implications for ice core records SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE air-snow exchange; ice core; formaldehyde; hydrogen peroxide; Greenland; snow ID TO-FIRN TRANSFER; SOUTH-POLE; ATMOSPHERIC CHEMISTRY; SURFACE SNOW; GREENLAND; SUMMIT; AIR; TROPOSPHERE; EXCHANGE; INCREASE AB [1] Sensitivity studies with physically based numerical air-snow-firn transfer models for formaldehyde (HCHO) and hydrogen peroxide (H2O2) show that even though nonlinear processes determine the preservation of HCHO and H2O2 in snow and firn, changes in atmospheric mixing ratios are linearly recorded in ice cores under otherwise constant environmental conditions. However, temperature, snowpack ventilation, and rate and timing of snow accumulation also affect the ice core records of reversibly deposited species and must be considered when inferring past atmospheric mixing ratios. The results of the sensitivity studies allow quantitative separation of these factors in ice core records. Past temperatures and accumulation rates are generally determined in ice cores and the preservation of HCHO and H2O2 is not highly sensitive to snowpack ventilation, leaving changes in seasonality of snow accumulation as the main source of uncertainty in a reconstruction of past atmospheric mixing ratios. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Desert Res Inst, Div Hydrol Sci, Reno, NV 89512 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. RP Hutterli, MA (reprint author), Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. EM manuel@hwr.arizona.edu; jmcconn@dri.edu; roger@hwr.arizona.edu; stewart@oasis.gsfc.nasa.gov NR 42 TC 47 Z9 47 U1 1 U2 11 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 15 PY 2003 VL 108 IS D1 AR 4023 DI 10.1029/2002JD002528 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655WZ UT WOS:000181576800012 ER PT J AU Miller, TM Ballenthin, JO Hunton, DE Viggiano, AA Wey, CC Anderson, BE AF Miller, TM Ballenthin, JO Hunton, DE Viggiano, AA Wey, CC Anderson, BE TI Nitric acid emission from the F100 jet engine SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE nitric acid; nitrous acid; nitrogen dioxide; hydroxyl radical; F100 jet engine; chemical ionization mass spectrometer ID CRUISE ALTITUDE; AIRCRAFT PLUMES; HNO3; COMBUSTION; EVOLUTION; AEROSOL AB [1] A chemical ionization mass spectrometer (CIMS) from the Air Force Research Laboratory at Hanscom AFB was used to measure levels of HNO3 in the exhaust stream of the F100 jet engine both in a test cell at NASA Glenn Research Center (GRC) at simulated altitudes 3-17 km and in flight behind F-16 aircraft at 9-11 km altitude. The HNO3 concentrations have been expressed as emission indices (EI) by normalizing to engine-produced CO2 measured by GRC instruments in the test cell and NASA-Langley Research Center instruments in flight. The test cell data showed that EI(HNO3) is independent of fuel sulfur level, and is highly dependent upon altitude for altitudes at which most commercial aircraft fly (below 12 km), mainly because the emission is a strong function of combustor inlet temperature, which is lower at high altitudes. EI(HNO3) at military power was 0.003 g NO2 kg(-1) fuel at low altitude (similar to3 km), and increased to 0.02 g kg(-1) for altitudes above 11 km. Operating the engine at 85% maximum turbine speed increased the figures above by a factor of about 2.5. At engine idle, EI(HNO3) was typically 0.14 g kg(-1). The decrease in EI(HNO3) with combustor inlet temperature is attributed to the temperature dependence of the NO2 + OH reaction producing HNO3. Comparing HNO3 emission indices with those measured at GRC for NO and NOx allowed us to determine the fraction of NO2 which is converted into HNO3 in the combustion process as a function of inlet temperature. Conversion of NO2 to HNO3 is 0.9% at military power for altitudes greater than or equal to11 km, and twice that at 85% maximum turbine speed. The conversion fraction changes dramatically in the 8-11 km altitude range, and is only 0.02% at 3 km altitude, for military power, or 0.2% at 85% maximum turbine speed. At engine idle, this fraction was about 8% at all altitudes. The accuracy of the (average) figures quoted above is +/-25%. The in situ data, obtained on 10 flights during the NASA Subsonic Near-Interaction Field (SNIF) experiment, are much less definitive but are consistent with the test cell results. C1 AF Res Lab, Space Vehicles Directorate, VSBXT, Hanscom AFB, MA 01731 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NASA, Engine Components Div, Army Res Lab, High Speed Syst Off,Glenn Res Ctr, Cleveland, OH 44135 USA. RP Miller, TM (reprint author), AF Res Lab, Space Vehicles Directorate, VSBXT, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. EM thomas.miller@hanscom.af.mil; john.ballenthin@hanscom.af.mil; donald.hunton@hanscom.af.mil; albert.viggiano@hanscom.af.mil; chowen.c.wey@grc.nasa.gov; b.e.anderson@larc.nasa.gov NR 22 TC 2 Z9 2 U1 1 U2 1 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 15 PY 2003 VL 108 IS D1 AR 4032 DI 10.1029/2001JD001522 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655WZ UT WOS:000181576800004 ER PT J AU Oreopoulos, L Marshak, A Cahalan, RF AF Oreopoulos, L Marshak, A Cahalan, RF TI Consistency of ARESE II cloud absorption estimates and sampling issues SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE atmospheric absorption; cloud absorption; solar radiation; 3-D effects; sampling; horizontal flux ID SHORTWAVE EXPERIMENT ARESE; SOLAR-RADIATION; AIRCRAFT MEASUREMENTS; ATMOSPHERE; SATELLITE; SURFACE AB [1] Data from three cloudy days (3, 21, and 29 March 2000) of the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment II (ARESE II) were analyzed and broadband absorptances were obtained for three sets of instruments. Grand (total flight) averages of fractional solar absorptances were similar to0.21-0.22, with the exception of 3 March when two sets of instruments gave values smaller by similar to0.03-0.04. The robustness of these values was evaluated by examining potential sampling problems with the aid of 500 nm spectral fluxes. The grand average of 500 nm apparent absorptance was statistically indistinguishable from zero for 21 and 29 March but acquired a large positive value of similar to0.10 on 3 March, which is not physically understood. We present results showing that each of the three days is unique in terms of cloud morphology and behavior of the absorptance time series. When the conditional sampling method is applied to the two days with reliable 500 nm absorptances (21 and 29 March), the resulting histogram of broadband absorptances is significantly narrower than the histogram constructed from the original time series. Corrections to the absorptance time series a la Cess et al. [1999] were successful for all three days because of the generally good correlation between broadband and 500 nm absorptances, removing the bulk of low-end and high-end extremes most likely associated with sampling and horizontal flux artifacts. The above two methods suggest an ARESE II range of broadband absorptances of similar to0.18-0.26. Finally, our study shows that the data set obtained on 29 March is the most self-consistent and straightforward to analyze among the three, because this day fulfilled all the requirements of the ARESE II experimental design, namely the presence of thick, overcast, homogeneous clouds. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Oreopoulos, L (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. EM lazaros@climate.gsfc.nasa.gov RI Oreopoulos, Lazaros/E-5868-2012; Cahalan, Robert/E-3462-2012; Marshak, Alexander/D-5671-2012 OI Oreopoulos, Lazaros/0000-0001-6061-6905; Cahalan, Robert/0000-0001-9724-1270; NR 19 TC 6 Z9 6 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 15 PY 2003 VL 108 IS D1 AR 4029 DI 10.1029/2002JD002243 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655WZ UT WOS:000181576800009 ER PT J AU Ridley, BA Atlas, EL Montzka, DD Browell, EV Cantrell, CA Blake, DR Blake, NJ Cinquini, L Coffey, MT Emmons, LK Cohen, RC DeYoung, RJ Dibb, JE Eisele, FL Flocke, FM Fried, A Grahek, FE Grant, WB Hair, JW Hannigan, JW Heikes, BJ Lefer, BL Mauldin, RL Moody, JL Shetter, RE Snow, JA Talbot, RW Thornton, JA Walega, JG Weinheimer, AJ Wert, BP Wimmers, AJ AF Ridley, BA Atlas, EL Montzka, DD Browell, EV Cantrell, CA Blake, DR Blake, NJ Cinquini, L Coffey, MT Emmons, LK Cohen, RC DeYoung, RJ Dibb, JE Eisele, FL Flocke, FM Fried, A Grahek, FE Grant, WB Hair, JW Hannigan, JW Heikes, BJ Lefer, BL Mauldin, RL Moody, JL Shetter, RE Snow, JA Talbot, RW Thornton, JA Walega, JG Weinheimer, AJ Wert, BP Wimmers, AJ TI Ozone depletion events observed in the high latitude surface layer during the TOPSE aircraft program SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; arctic; surface layer; ozone depletion; TOPSE ID POLAR SUNRISE EXPERIMENT; ARCTIC BOUNDARY-LAYER; TROPOSPHERIC OZONE; HALOGEN COMPOUNDS; BROMINE OXIDE; PHOTOCHEMICAL PRODUCTION; HYDROCARBON MEASUREMENTS; ATOM CONCENTRATIONS; CARBONYL-COMPOUNDS; NY-ALESUND AB [1] During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) aircraft program, ozone depletion events (ODEs) in the high latitude surface layer were investigated using lidar and in situ instruments. Flight legs of 100 km or longer distance were flown 32 times at 30 m altitude over a variety of regions north of 58degrees between early February and late May 2000. ODEs were found on each flight over the Arctic Ocean but their occurrence was rare at more southern latitudes. However, large area events with depletion to over 2 km altitude in one case were found as far south as Baffin Bay and Hudson Bay and as late as 22 May. There is good evidence that these more southern events did not form in situ but were the result of export of ozone-depleted air from the surface layer of the Arctic Ocean. Surprisingly, relatively intact transport of ODEs occurred over distances of 900-2000 km and in some cases over rough terrain. Accumulation of constituents in the frozen surface over the dark winter period cannot be a strong prerequisite of ozone depletion since latitudes south of the Arctic Ocean would also experience a long dark period. Some process unique to the Arctic Ocean surface or its coastal regions remains unidentified for the release of ozone-depleting halogens. There was no correspondence between coarse surface features such as solid ice/snow, open leads, or polynyas with the occurrence of or intensity of ozone depletion over the Arctic or subarctic regions. Depletion events also occurred in the absence of long-range transport of relatively fresh "pollution'' within the high latitude surface layer, at least in spring 2000. Direct measurements of halogen radicals were not made. However, the flights do provide detailed information on the vertical structure of the surface layer and, during the constant 30 m altitude legs, measurements of a variety of constituents including hydroxyl and peroxy radicals. A summary of the behavior of these constituents is made. The measurements were consistent with a source of formaldehyde from the snow/ice surface. Median NOx in the surface layer was 15 pptv or less, suggesting that surface emissions were substantially converted to reservoir constituents by 30 m altitude and that ozone production rates were small (0.15-1.5 ppbv/d) at this altitude. Peroxyacetylnitrate (PAN) was by far the major constituent of NOy in the surface layer independent of the ozone mixing ratio. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. RP Ridley, BA (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM ridley@acd.ucar.edu RI Cohen, Ronald/A-8842-2011; Grant, William/B-8311-2009; Atlas, Elliot/J-8171-2015; Lefer, Barry/B-5417-2012; Emmons, Louisa/R-8922-2016; Thornton, Joel/C-1142-2009 OI Cohen, Ronald/0000-0001-6617-7691; Grant, William/0000-0002-1439-3285; Lefer, Barry/0000-0001-9520-5495; Emmons, Louisa/0000-0003-2325-6212; Thornton, Joel/0000-0002-5098-4867 NR 72 TC 45 Z9 46 U1 1 U2 4 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 15 PY 2003 VL 108 IS D4 AR 8356 DI 10.1029/2001JD001507 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 659VJ UT WOS:000181797900004 ER PT J AU Smirnov, A Holben, BN Dubovik, O Frouin, R Eck, TF Slutsker, I AF Smirnov, A Holben, BN Dubovik, O Frouin, R Eck, TF Slutsker, I TI Maritime component in aerosol optical models derived from Aerosol Robotic Network data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol optical depth; Sun photometer; maritime aerosol; atmospheric correction; retrieval; phase function ID MARINE BOUNDARY-LAYER; CHARACTERIZATION EXPERIMENT ACE-1; SKY RADIANCE MEASUREMENTS; INDIAN-OCEAN EXPERIMENT; SIZE DISTRIBUTION; ATMOSPHERIC CORRECTION; ANTHROPOGENIC AEROSOLS; COLOR IMAGERY; PARTICLE-SIZE; MACE HEAD AB [1] Aerosol optical properties above the oceans vary considerably, depending on contributions of major aerosol components, i.e., urban/industrial pollution, desert dust, biomass burning, and maritime. The optical characterization of these aerosols is fundamental to the parameterization of radiative forcing models as well as to the atmospheric correction of ocean color imagery. We present a model of the maritime aerosol component derived using Aerosol Robotic Network (AERONET) data from three island locations: Bermuda (Atlantic Ocean), Lanai, Hawaii (Pacific Ocean), and Kaashidhoo, Maldives (Indian Ocean). To retrieve the maritime component, we have considered the data set with aerosol optical depth at a wavelength 500 nm less than 0.15 and Angstrom parameter alpha less than 1. The inferred maritime component in the columnar size distribution, which was found to be very similar for the three study sites, is bimodal with a fine mode at an effective radius (r(eff)) similar to 0.11-0.14 mum and a coarse mode r(eff) of similar to1.8-2.1 mum. The results are comparable with size distributions reported in the literature. The refractive index is spectrally independent and estimated to be 1.37-0.001i (single-scattering albedo is about 0.98), based on the single-component homogenous particle composition assumption. Fractional contributions of the fine and coarse modes to the computed tau(a) (500 nm) are within the range of tau(fine) similar to0.03-0.05 and tau(coarse) similar to 0.05-0.06 correspondingly. Angstrom parameters vary from similar to0.8 to 1.0 computed in the UV-visible (340-670 nm) and from 0.4 to 0.5 estimated in the near IR (870-2130 nm) spectral ranges. Aerosol phase functions are very similar for all three sites considered. The maritime aerosol component presented in this paper can serve as a candidate model in atmospheric correction algorithms. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92037 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Smirnov, A (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Code 923, Greenbelt, MD 20771 USA. EM asmirnov@aeronet.gsfc.nasa.gov; brent@aeronet.gsfc.nasa.gov; dubovik@aeronet.gsfc.nasa.gov; rfrouin@ucsd.edu; tom@aeronet.gsfc.nasa.gov; ilya@aeronet.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; ECK, THOMAS/D-7407-2012 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; NR 55 TC 68 Z9 69 U1 0 U2 2 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 15 PY 2003 VL 108 IS D1 AR 4033 DI 10.1029/2002JD002701 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655WZ UT WOS:000181576800014 ER PT J AU Kodibagkar, VD Fedders, PA Browning, CD Bowman, RC Adolphi, NL Conradi, MS AF Kodibagkar, VD Fedders, PA Browning, CD Bowman, RC Adolphi, NL Conradi, MS TI Vacancy ordering phase transition in ZrBe2(H/D)(x): NMR and electronic structure study SO PHYSICAL REVIEW B LA English DT Article ID HYDROGEN DIFFUSION; ZRBE2H1.4 AB The layered intermetallic compound ZrBe2(H/D)(x) (xsimilar or equal to1.5) was studied using deuterium and beryllium NMR. A temperature-induced structural transition in the deuteride reported earlier is further investigated here using Be-9 NMR, which reveals the transition in both the hydride and deuteride at 200 and 235 K, respectively. Above the transition temperature a single pair of quadrupolar satellites is present. Each quadrupolar satellite splits into two resonances below the transition temperature, implying the existence of two different classes of Be sites. The temperature dependence of the satellite frequencies and the appearance of two-phase coexistence spectra show the transition to be first order. Be-D spin-echo double resonance (SEDOR) experiments were performed to identify the two sites; SEDOR demonstrates that the D environments of the two classes of Be sites are similar. Electronic structure calculations show the binding energy of H decreases gradually for x greater than 1.38. The calculations allow a vacancy ordered structure to be proposed. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Knox Coll, Galesburg, IL 61401 USA. RP Kodibagkar, VD (reprint author), Univ Texas, SW Med Ctr, Dept Radiol, 5323 Harry Hines Blvd, Dallas, TX 75390 USA. NR 16 TC 3 Z9 3 U1 0 U2 1 PU AMERICAN 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 JAN 15 PY 2003 VL 67 IS 4 AR 045107 DI 10.1103/PhysRevB.67.045107 PG 7 WC Physics, Condensed Matter SC Physics GA 646CA UT WOS:000181016200018 ER PT J AU Wu, J Walukiewicz, W Yu, KM Ager, JW Haller, EE Miotkowski, I Ramdas, AK Su, CH Sou, IK Perera, RCC Denlinger, JD AF Wu, J Walukiewicz, W Yu, KM Ager, JW Haller, EE Miotkowski, I Ramdas, AK Su, CH Sou, IK Perera, RCC Denlinger, JD TI Origin of the large band-gap bowing in highly mismatched semiconductor alloys SO PHYSICAL REVIEW B LA English DT Article ID NITROGEN-INDUCED INCREASE; ELECTRONIC-STRUCTURE; ZNSE; ZNTE AB Photomodulated reflection, optical absorption, and photoluminescence spectroscopies have been used to measure the composition dependence of interband optical transitions in ZnSe1-xTex and ZnS1-xTex alloys. The results reveal entirely different origins of the large band-gap bowing for small and large Te content. On the Te-rich side, the reduction of the band gap is well explained by the band anticrossing interaction between the Se or S localized states and the ZnTe conduction-band states. On the Se- or S-rich side, an interaction between the localized Te states and the degenerate Gamma valence bands of ZnSe or ZnS is responsible for the band-gap reduction and the rapid increase of the spin-orbit splitting with increasing Te concentration. Results of the soft-x-ray emission experiment provide direct proof of the valence-band anticrossing interaction. The band-gap bowing in the entire composition range is accounted for by a linear interpolation between the conduction-band anticrossing and valence-band anticrossing models. C1 Univ Calif Berkeley, Appl Sci & Technol Grad Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NASA, George C Marshall Space Flight Ctr, Sci Directorate SD46, Huntsville, AL 35812 USA. Hong Kong Univ Sci & Technol, Dept Phys, Kowloon, Hong Kong, Peoples R China. Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. RP Wu, J (reprint author), Univ Calif Berkeley, Appl Sci & Technol Grad Grp, Berkeley, CA 94720 USA. RI Wu, Junqiao/G-7840-2011; Yu, Kin Man/J-1399-2012 OI Wu, Junqiao/0000-0002-1498-0148; Yu, Kin Man/0000-0003-1350-9642 NR 21 TC 39 Z9 39 U1 2 U2 15 PU AMERICAN 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 JAN 15 PY 2003 VL 67 IS 3 AR 035207 DI 10.1103/PhysRevB.67.035207 PG 5 WC Physics, Condensed Matter SC Physics GA 644WR UT WOS:000180943800058 ER PT J AU Neugebauer, M Liewer, PC AF Neugebauer, M Liewer, PC TI Creation and destruction of transitory coronal holes and their fast solar wind streams SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind; coronal holes ID OPEN MAGNETIC-FLUX; EVOLUTION; CYCLE; FIELD AB A qualitative model is proposed whereby foot point exchange diffusion of open field lines from a solar active region may have led to the formation of a coronal hole and a corotating stream of fast solar wind. The solar wind speed changed from fast back to slow when the coronal hole was later disrupted by the emergence of a new active region. A corollary of this model is that a corotating interplanetary field line may have both fast and slow solar wind at different places along its length. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Neugebauer, M (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NR 20 TC 7 Z9 7 U1 0 U2 0 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 11 PY 2003 VL 108 IS A1 AR 1013 DI 10.1029/2002JA009326 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 655QJ UT WOS:000181563700002 ER PT J AU Slavin, JA Lepping, RP Gjerloev, J Fairfield, DH Hesse, M Owen, CJ Moldwin, MB Nagai, T Ieda, A Mukai, T AF Slavin, JA Lepping, RP Gjerloev, J Fairfield, DH Hesse, M Owen, CJ Moldwin, MB Nagai, T Ieda, A Mukai, T TI Geotail observations of magnetic flux ropes in the plasma sheet SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TRAVELING COMPRESSION REGIONS; ISEE 3 OBSERVATIONS; EARTHS MAGNETOTAIL; DISTANT MAGNETOTAIL; GEOMAGNETIC TAIL; FIELD; RECONNECTION; SPACECRAFT; EJECTION; AVERAGE AB Examination of Geotail measurements in the near-tail (X > 30 R(E)) has revealed the presence of small flux ropes in the plasma sheet. A total of 73 flux rope events were identified in the Geotail magnetic field measurements between November 1998 and April 1999. This corresponds to an estimated occurrence frequency of similar to1 flux rope per 5 hours of central plasma sheet observing time. All of the flux ropes were embedded within high-speed plasma sheet flows with 35 directed Earthward, (V(x)) = 431 km/s, and 38 moving tailward, (V(x)) = -451 km/s. We refer to these two populations as "BBF-type" and "plasmoid-type" flux ropes. The flux ropes were usually several tens of seconds in duration, and the two types were readily distinguished by the sense of their quasisinusoidal DeltaB(z) perturbations, i.e., -/+ for the "BBF" events and +/- for the "plasmoid" events. Most typically, a flux rope was observed to closely follow the onset of a high-speed flow within similar to1-2 min. Application of the Lepping-Burlag-alpha constant-alpha flux rope model (i.e., J = alphaB) to these events showed that approximately 60% of each class could be acceptably described as cylindrical, force-free flux ropes. The modeling results yielded mean flux rope diameters and core field intensities of 1.4 R(E) and 20 nT and 4.4 R(E) and 14 nT for the BBF and plasmoid-type events, respectively. The inclinations of the flux ropes were small relative to the GSM X-Y plane, but a wide range of azimuthal orientations were determined within that plane. The frequent presence of these flux ropes in the plasma sheet is interpreted as strong evidence for multiple reconnection X-lines (MRX) in the near-tail. Hence, our results suggest that reconnection in the near-tail may closely resemble that at the dayside magnetopause where MRX reconnection has been hypothesized to be responsible for the generation of flux transfer events. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Univ Calif Los Angeles, ESS Inst Geophys & Planetary Phys, Los Angeles, CA USA. Tokyo Inst Technol, Dept Earth & Planetary Sci, Meguro Ku, Tokyo 1528551, Japan. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. RP Slavin, JA (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. EM james.a.slavin@gsfc.nasa.gov RI Owen, Christopher/C-2999-2008; Moldwin, Mark/F-8785-2011; Hesse, Michael/D-2031-2012; Slavin, James/H-3170-2012 OI Owen, Christopher/0000-0002-5982-4667; Moldwin, Mark/0000-0003-0954-1770; Slavin, James/0000-0002-9206-724X NR 60 TC 176 Z9 181 U1 0 U2 16 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 11 PY 2003 VL 108 IS A1 AR 1015 DI 10.1029/2002JA009557 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 655QJ UT WOS:000181563700005 ER PT J AU Lamer, G McHardy, IM Uttley, P Jahoda, K AF Lamer, G McHardy, IM Uttley, P Jahoda, K TI X-ray spectral variability of the Seyfert galaxy NGC 4051 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : individual : NGC 4051; galaxies : Seyfert; X-rays : galaxies ID RXTE OBSERVATIONS; ACCRETION DISK; ALPHA EMISSION; BLACK-HOLE; SWAN SONG; NGC-4051; LINE; MCG-6-30-15; ULTRAVIOLET; ABSORPTION AB We report on the X-ray spectral variability of the Seyfert 1 galaxy NGC 4051 observed with the Rossi X-ray Timing Explorer (RXTE) during a 1000-d period between 1996 May and 1999 March. The spectra were obtained as part of monitoring observations and from two long observations using the RXTE Proportional Counter Array (PCA). During the monitoring period the 2-10 keV flux of NGC 4051 varied between 10(-12) and 7 x 10(-11) erg cm (-2) s (-1). We re-analysed RXTE PCA observations from a distinct low state in 1998 May using the latest background and detector response models. The RXTE and BeppoSAX observations of NGC 4051 during the low state show a very hard spectrum with a strong unresolved fluorescence line. This emission, probably caused by reflection from a molecular torus, is likely to be constant over long time-scales and is therefore assumed as an underlying component at all flux states. By subtracting the torus component we are able to determine the spectral variability of the primary continuum. In the variable component we observe a strong anticorrelation of X-ray flux and spectral hardness in the PCA energy band. We show that the changes in hardness are caused by slope variability of the primary power-law spectrum rather than by changing reflection or variable photoelectric absorption. The primary spectral index varies between 2) candidates that are selected using an ultrasteep radio spectrum criterion fail to show optical emission (continuum, lines) in deep Keck exposures. Their parent objects are only detected in the near-IR and are probably heavily obscured and/or at very high redshift. To search for signatures of dust and help constrain the nature and redshifts of these "no-z" radio galaxies, we have conducted a program of submillimeter and millimeter observations. Here we report the first results of a detailed study of one of these objects, WN J0305+3525. It appears associated with a small group of Ksimilar to21-22 objects and is strongly detected at both 850 mum and 1.25 mm. On the basis of its faint K-band magnitude, spectral energy distribution, and other evidence, we estimate that the radio galaxy is probably at a redshift zsimilar or equal to3+/-1. This would make WN J0305-3525 a radio-loud hyperluminous infrared galaxy (L(FIR)similar to10(13) L-circle dot) similar to, but more obscured than, other dusty radio galaxies in this redshift range. This, together with the absence of Lyalpha emission and compact (thetaless than or similar to1".9) radio structure, suggests that WN J0305+3525 is embedded in a very dense, dusty medium and is probably at an early stage of its formation. C1 Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Inst Astrophys Paris, F-75014 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Reuland, M (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, L-413,POB 808, Livermore, CA 94551 USA. OI De Breuck, Carlos/0000-0002-6637-3315 NR 38 TC 2 Z9 2 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 10 PY 2003 VL 582 IS 2 BP L71 EP L74 DI 10.1086/367689 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 633KQ UT WOS:000180282800003 ER PT J AU Still, CJ Berry, JA Collatz, GJ DeFries, RS AF Still, CJ Berry, JA Collatz, GJ DeFries, RS TI Global distribution of C-3 and C-4 vegetation: Carbon cycle implications SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article DE C-4 photosynthesis; discrimination; carbon cycle; carbon isotopes; double deconvolution; global ecology ID SURFACE PARAMETERIZATION SIB2; NET PRIMARY PRODUCTION; ATMOSPHERIC CO2; ISOTOPE DISCRIMINATION; LAND-USE; TERRESTRIAL ECOSYSTEMS; STOMATAL CONDUCTANCE; FUNCTIONAL TYPES; MIXED PRAIRIE; NORTH-AMERICA AB The global distribution of C-3 and C-4 plants is required for accurately simulating exchanges of CO2, water, and energy between the land surface and atmosphere. It is also important to know the C-3/C-4 distribution for simulations of the carbon isotope composition of atmospheric CO2 owing to the distinct fractionations displayed by each photosynthetic type. Large areas of the land surface are spatial and temporal mosaics of both photosynthetic types. We developed an approach for capturing this heterogeneity by combining remote sensing products, physiological modeling, a spatial distribution of global crop fractions, and national harvest area data for major crop types. Our C-3/C-4 distribution predicts the global coverage of C4 vegetation to be 18.8 million km(2), while C-3 vegetation covers 87.4 million km(2). We incorporated our distribution into the SiB2 model and simulated carbon fluxes for each photosynthetic type. The gross primary production (GPP) of C4 plants is 35.3 Pg C yr(-1), or similar to23% of total GPP, while that of C-3 plants is 114.7 Pg C yr(-1). The assimilation-weighted terrestrial discrimination against (CO2)-C-13 is 16.5parts per thousand. If the terrestrial component of the carbon sink is proportional to GPP, this implies a net uptake of 2.4 Pg C yr(-1) on land and 1.4 Pg C yr(-1) in the ocean using a C-13 budgeting approach and average carbon cycle parameter values for the 1990s. We also simulated the biomass of each photosynthetic type using the CASA model. The simulated biomass values of C-3 and C-4 vegetation are 389.3 and 18.6 Pg C, respectively. C1 Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94305 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RP Still, CJ (reprint author), Univ Calif Berkeley, Berkeley Atmospher Sci Ctr, 307 McCone Hall, Berkeley, CA 94720 USA. RI Berry, Joseph/B-8211-2009; collatz, george/D-5381-2012 OI Berry, Joseph/0000-0002-5849-6438; NR 84 TC 229 Z9 235 U1 7 U2 88 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JAN 10 PY 2003 VL 17 IS 1 AR 1006 DI 10.1029/2001GB001807 PG 14 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 655GY UT WOS:000181544000001 ER PT J AU Kharuk, VI Ranson, KJ Burenina, TA Fedotova, EV AF Kharuk, VI Ranson, KJ Burenina, TA Fedotova, EV TI Mapping of Siberian forest landscapes along the Yenisey transect with AVHRR SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID COVER; VEGETATION; CLASSIFICATION; IMAGERY AB In this paper NOAA AVHRR data acquired at the Sukachev Institute of Forest in Siberia, Russia is evaluated for forest management mapping applications. First a classification of the entire 1000 km x 3000 km transect was performed, but was found to be too general to be of value. More useful interpretation procedures require a landscape-ecological approach. This means that computer classification should be made separately for segments of territory based ecologically distinct regions. This segmentation of the transect into ecological regions was found to improve the level of detail available in the classification. Using this approach AVHRR data were found to be adequate for small scale mapping at the level of vegetation types or plant formations. A limited study using AVHRR data for classification of mountainous regions showed that AVHRR-derived maps were more detailed than existing landscape maps. AVHRR derived classifications also compared favourably to larger scale forest management maps of softwood and hardwood forests. Current forest management in Siberia relies on very small-scale inventory maps. Thus, there is a potential role for AVHRR (or Terra) data for northern Siberian forest monitoring. The southern forests of the Yenisey meridian (below the 57th parallel) are less uniform due to considerable human activity, and NOAA/AVHRR data will play a subordinate role in its monitoring. C1 Sukachev Inst Forest, Krasnoyarsk, Russia. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Kharuk, VI (reprint author), Sukachev Inst Forest, Krasnoyarsk, Russia. RI Ranson, Kenneth/G-2446-2012; Буренина, Тамара/F-2887-2016; Fedotova, Elena/K-4573-2015 OI Ranson, Kenneth/0000-0003-3806-7270; NR 30 TC 4 Z9 6 U1 1 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 10 PY 2003 VL 24 IS 1 BP 23 EP 37 DI 10.1080/0143116021000021143 PG 15 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 639JK UT WOS:000180624800003 ER PT J AU Andrefouet, S Robinson, JA AF Andrefouet, S Robinson, JA TI The use of Space Shuttle images to improve cloud detection in mapping of tropical coral reef environments SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID PHOTOGRAPHS AB Landsat and SPOT sensor data used for coral reef mapping were combined with multidate Space Shuttle photographs and digital video to distinguish small clouds from reef features. By using public-domain data from human spaceflights, we could use multidate techniques to improve mapping while reducing the number of satellite sensor images that had to be purchased. Results are illustrated for South Pacific atolls. C1 Univ S Florida, Coll Marine Sci, Remote Sensing Biol Oceanog Lab, St Petersburg, FL 33701 USA. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Image Anal Lab, Houston, TX 77058 USA. RP Andrefouet, S (reprint author), Univ S Florida, Coll Marine Sci, Remote Sensing Biol Oceanog Lab, 140,7th Av S, St Petersburg, FL 33701 USA. OI Robinson, Julie/0000-0002-6832-6459 NR 14 TC 4 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JAN 10 PY 2003 VL 24 IS 1 BP 143 EP 149 DI 10.1080/01431160110109615 PG 7 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 639JK UT WOS:000180624800010 ER PT J AU Hitchman, MH Buker, ML Tripoli, GJ Browell, EV Grant, WB McGee, TJ Burris, JF AF Hitchman, MH Buker, ML Tripoli, GJ Browell, EV Grant, WB McGee, TJ Burris, JF TI Nonorographic generation of Arctic polar stratospheric clouds during December 1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE gravity waves; polar stratospheric clouds (PSCs); synoptic waves; mesoscale modeling; Rossby wave breaking; ozone ID GRAVITY-WAVES; OZONE DEPLETION; MOUNTAIN WAVES; SIMULATION; MODEL; CYCLONE; SYSTEM; VORTEX AB During December 1999, polar stratospheric clouds (PSCs) were observed in the absence of conditions conducive to generation by topographic gravity waves. The possibility is explored that PSCs can be generated by inertia gravity waves (IGW) radiating from breaking synoptic-scale Rossby waves on the polar front jet. The aerosol features on 7 and 12 December are selected for comparison with theory and with simulations using the University of Wisconsin Nonhydrostatic Modeling System (UWNMS). Consistent with Rossby adjustment theory, a common feature in the UWNMS simulations is radiation of IGW from the tropopause polar front jet, especially from sectors which are evolving rapidly in the Rossby wave breaking process. Packets of gravity wave energy radiate upward and poleward into the cold pool, while individual wave crests propagate poleward and downward, causing mesoscale variations in vertical motion and temperature. On 12 December the eastbound DC-8 lidar observations exhibited a fairly uniform field of six waves in aerosol enhancement in the 14-20 km layer, consistent with vertical displacement by a field of IGW propagating antiparallel to the flow, with characteristic horizontal and vertical wavelengths of similar to300 and similar to10 km. UWNMS simulations show emanation of a field of IGW upward and southwestward from a northward incursion of the polar front jet. The orientation and evolution of the aerosol features on 7 December are consistent with a single PSC induced by an IGW packet propagating from a breaking Rossby wave over western Russia toward the northeast into the coldest part of the base of the polar vortex, with characteristic period similar to9 hours, vertical wavelength similar to12 km, and horizontal wavelength similar to1000 km. Linear theory shows that for both of these cases, IGW energy propagates upward at similar to1 km/hour and horizontally at similar to100 km/hour, with characteristic trace speed similar to30 m/s. The spatial orientation of the PSC along IGW phase lines is contrasted with the nearly horizontal filamentary structures in the PSC, which are indicative of flow streamlines. It is suggested that vertical displacement is a crucial factor in determining whether a PSC will form and that most PSCs are relatable to specific synoptic and mesoscale motions. C1 Univ Wisconsin, Dept Atmospher Sci, Madison, WI USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hitchman, MH (reprint author), Univ Wisconsin, Dept Atmospher & Ocean Sci, 1225 W Dayton St, Madison, WI 53706 USA. EM matt@aos.wisc.edu; marcus@aos.wisc.edu; tripoli@aos.wisc.edu; e.v.browell@larc.nasa.gov; w.b.grant@larc.nasa.gov; mcgee@hyperion.gsfc.nasa.gov; john.burris@gsfc.nasa.gov RI Grant, William/B-8311-2009; McGee, Thomas/G-4951-2013 OI Grant, William/0000-0002-1439-3285; NR 35 TC 26 Z9 26 U1 0 U2 3 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 10 PY 2003 VL 108 IS D1 AR 8325 DI 10.1029/2001JD001034 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655LV UT WOS:000181554600003 ER PT J AU Shindell, D AF Shindell, D TI Whither Arctic climate? SO SCIENCE LA English DT Editorial Material ID GENERAL-CIRCULATION MODEL; STRATOSPHERIC OZONE; TEMPERATURE; SIMULATIONS; CHEMISTRY; TRENDS; IMPACT; LAYER C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Shindell, D (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM dshindell@giss.nasa.gov NR 17 TC 10 Z9 11 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JAN 10 PY 2003 VL 299 IS 5604 BP 215 EP 216 DI 10.1126/science.1080855 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 633LD UT WOS:000180284000027 PM 12522240 ER PT J AU Austin, J Shindell, D Beagley, SR Bruhl, C Dameris, M Manzini, E Nagashima, T Newman, P Pawson, S Pitari, G Rozanov, E Schnadt, C Shepherd, TG AF Austin, J Shindell, D Beagley, SR Bruhl, C Dameris, M Manzini, E Nagashima, T Newman, P Pawson, S Pitari, G Rozanov, E Schnadt, C Shepherd, TG TI Uncertainties and assessments of chemistry-climate models of the stratosphere SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Review ID MIDDLE ATMOSPHERE MODEL; GENERAL-CIRCULATION MODEL; GRAVITY-WAVE DRAG; DOPPLER-SPREAD PARAMETERIZATION; NORTHERN-HEMISPHERE WINTER; WEATHER PREDICTION MODELS; WATER-VAPOR; ARCTIC STRATOSPHERE; OZONE RESPONSE; GLOBAL CLIMATE AB In recent years a number of chemistry-climate models have been developed with an emphasis on the stratosphere. Such models cover a wide range of time scales of integration and vary considerably in complexity. The results of specific diagnostics are here analysed to examine the differences amongst individual models and observations, to assess the consistency of model predictions, with a particular focus on polar ozone. For example, many models indicate a significant cold bias in high latitudes, the "cold pole problem", particularly in the southern hemisphere during winter and spring. This is related to wave propagation from the troposphere which can be improved by improving model horizontal resolution and with the use of non-orographic gravity wave drag. As a result of the widely differing modelled polar temperatures, different amounts of polar stratospheric clouds are simulated which in turn result in varying ozone values in the models. The results are also compared to determine the possible future behaviour of ozone, with an emphasis on the polar regions and mid-latitudes. All models predict eventual ozone recovery, but give a range of results concerning its timing and extent. Differences in the simulation of gravity waves and planetary waves as well as model resolution are likely major sources of uncertainty for this issue. In the Antarctic, the ozone hole has probably reached almost its deepest although the vertical and horizontal extent of depletion may increase slightly further over the next few years. According to the model results, Antarctic ozone recovery could begin any year within the range 2001 to 2008. The limited number of models which have been integrated sufficiently far indicate that full recovery of ozone to 1980 levels may not occur in the Antarctic until about the year 2050. For the Arctic, most models indicate that small ozone losses may continue for a few more years and that recovery could begin any year within the range 2004 to 2019. The start of ozone recovery in the Arctic is therefore expected to appear later than in the Antarctic. Further, interannual variability will tend to mask the signal for longer than in the Antarctic, delaying still further the date at which ozone recovery may be said to have started. Because of this inherent variability of the system, the decadal evolution of Arctic ozone will not necessarily be a direct response to external forcing. C1 Meteorol Off, Bracknell RG12 2SZ, Berks, England. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. York Univ, N York, ON M3J 1P3, Canada. Max Planck Inst Chem, D-55128 Mainz, Germany. DLR, Oberpfaffenhofen, Germany. Max Planck Inst Meteorol, Hamburg, Germany. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Univ Aquila, Dipartimento Fis, I-67010 Coppito, Italy. IAC ETH, PMOD, WRC, CH-7260 Davos, Switzerland. Univ Toronto, Dept Phys, Toronto, ON, Canada. RP Austin, J (reprint author), Meteorol Off, London Rd, Bracknell RG12 2SZ, Berks, England. EM john.austin@metoffice.com RI Manzini, Elisa/H-5760-2011; Shindell, Drew/D-4636-2012; Newman, Paul/D-6208-2012; Rozanov, Eugene/A-9857-2012; Pawson, Steven/I-1865-2014; OI Newman, Paul/0000-0003-1139-2508; Rozanov, Eugene/0000-0003-0479-4488; Pawson, Steven/0000-0003-0200-717X; Pitari, Giovanni/0000-0001-7051-9578 NR 110 TC 196 Z9 201 U1 1 U2 14 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JAN 9 PY 2003 VL 3 BP 1 EP 27 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 634FP UT WOS:000180329600001 ER PT J AU Wu, YH Brashers, B Finkelstein, PL Pleim, JE AF Wu, YH Brashers, B Finkelstein, PL Pleim, JE TI A multilayer biochemical dry deposition model - 2. Model evaluation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE multiplayer; biochemical; dry; deposition; model ID CO2; TRANSPIRATION; NITROGEN AB The multilayer biochemical dry deposition model (MLBC) described in the accompanying paper was tested against half-hourly eddy correlation data from six field sites under a wide range of climate conditions with various plant types. Modeled CO2, O-3, SO2, and H2O (latent heat) fluxes were compared with measurements. Model outputs have good correlations with measurements at all locations. Correlation coefficients between model outputs and measurements at all sites range from 0.72 to 0.96 for CO2 flux, from 0.84 to 0.98 for H2O flux, from 0.77 to 0.95 for O-3 flux, and from 0.36 to 0.86 for SO2 flux. Model sensitivity analyses were conducted to investigate the variation of model outputs due to measurement errors of input variables and to changes of environmental conditions such as changes in weather conditions. The MLBC outputs were also compared with outputs from the Multilayer Model (MLM) model [Meyers et al., 1998] and the Regional Acid Deposition Model (RADM) [Wesely, 1989] at two typical sites. Comparisons show that the MLBC performs better than the other two models. The model is suitable for use in nationwide dry deposition networks, for example, the Clean Air Status And Trends Network (CASTNet). It can be used to assist in describing total pollutant loadings to major ecosystems. With some modifications, the model may also be suitable for inclusion in region (meso-) scale numerical models, for example, the Community Multiscale Air Quality (CMAQ) model. C1 US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC USA. RP Wu, YH (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, NASA-GSFC Code 974, Greenbelt, MD 20771 USA. EM ywu@hsb.gsfc.nasa.gov RI Pleim, Jonathan Pleim/C-1331-2017 OI Pleim, Jonathan Pleim/0000-0001-6190-6082 NR 17 TC 6 Z9 6 U1 1 U2 3 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 9 PY 2003 VL 108 IS D1 AR 4014 DI 10.1029/2002JD002306 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655LP UT WOS:000181554000003 ER PT J AU Wu, YH Brashers, B Finkelstein, PL Pleim, JE AF Wu, YH Brashers, B Finkelstein, PL Pleim, JE TI A multilayer biochemical dry deposition model - 1. Model formulation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE multilayer; biochemical; dry; deposition; model ID STOMATAL CONDUCTANCE; SULFUR-DIOXIDE; PARTITION-COEFFICIENTS; ANGLE DISTRIBUTION; VEGETATION; HEAT; PHOTOSYNTHESIS; SURFACES; LEAVES; PARAMETERIZATION AB A multilayer biochemical dry deposition model has been developed based on the NOAA Multilayer Model (MLM; Meyers et al. [1998]) to study gaseous exchanges between the soil, plants, and the atmosphere. Most of the parameterizations and submodels have been updated or replaced. The numerical integration was improved, and an aerodynamic resistance based on Monin-Obukhov theory was added. An appropriate parameterization for the leaf boundary layer resistance was chosen. A biochemical stomatal resistance model was chosen based on comparisons of four different existing stomatal resistance schemes. It describes photosynthesis and respiration and their coupling with stomatal resistance for sunlit and shaded leaves separately. Various aspects of the photosynthetic process in both C-3 and C-4 plants are considered in the model. To drive the photosynthesis model, the canopy radiation scheme has been updated. Leaf area index measurements are adjusted to account for stem area index. A normalized soil water stress factor was applied to potential photosynthesis to account for plant response to both drought and water-logging stresses. A new cuticle resistance model was derived based on membrane passive transport theory and Fick's first law. It accounts for the effects of diffusivity and solubility of specific gases in the cuticle membrane, as well as the thickness of the cuticle membrane. The model is designed for use in the nationwide dry deposition networks, for example, the Clean Air Status And Trends Network (CASTNet), and mesoscale models, for example, the Community Multiscale Air Quality model (CMAQ) and even the Weather Research and Forecasting model (WRF). C1 US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC USA. RP Wu, YH (reprint author), NASA, Goddard Space Flight Ctr, NASA-GSFC Code 974, Greenbelt, MD 20771 USA. EM ywu@hsb.gsfc.nasa.gov RI Pleim, Jonathan Pleim/C-1331-2017 OI Pleim, Jonathan Pleim/0000-0001-6190-6082 NR 62 TC 23 Z9 23 U1 0 U2 10 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 9 PY 2003 VL 108 IS D1 AR 4013 DI 10.1029/2002JD002293 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655LP UT WOS:000181554000002 ER PT J AU Chao, Y Li, ZJ Kindle, JC Paduan, JD Chavez, FP AF Chao, Y Li, ZJ Kindle, JC Paduan, JD Chavez, FP TI A high-resolution surface vector wind product for coastal oceans: Blending satellite scatterometer measurements with regional mesoscale atmospheric model simulations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB A 2-dimensional variational method is used to blend the satellite scatterometer measured (QuikSCAT) and regional mesoscale atmospheric model simulated (COAMPS) surface vector winds for coastal central California. The approach is distinct from existing methods in that it considers errors from both measurements and models. When compared with independent in situ observations, the blended wind product shows consistently higher correlation and smaller RMS errors than QuikSCAT or COAMPS winds. The proposed algorithm can be implemented over any part of the world ocean. It should be a valuable tool for describing small-scale atmospheric processes in coastal zones and for forcing high-resolution coastal ocean models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Raytheon ITSS, Pasadena, CA 91101 USA. USN, Res Lab, Stennis Space Ctr, MS 39529 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. RP Chao, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. NR 6 TC 17 Z9 18 U1 1 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 8 PY 2003 VL 30 IS 1 AR 1013 DI 10.1029/2002GL015729 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 655GU UT WOS:000181543600001 ER PT J AU Stoner, AW Ottmar, ML AF Stoner, AW Ottmar, ML TI Relationships between size-specific sediment preferences and burial capabilities in juveniles of two Alaska flatfishes SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE habitat selection; behavior; sediment; halibut; rock sole; crypsis ID PLAICE PLEURONECTES-PLATESSA; FLOUNDER PSEUDOPLEURONECTES-AMERICANUS; WINTER FLOUNDER; BURYING ABILITY; KODIAK-ISLAND; GRAIN-SIZE; BERING SEA; SELECTION; HABITAT; PREDATION AB Laboratory experiments with juvenile Pacific halibut (Hippoglossus stenolepis Schmidt) (31-150 min TL) and northern rock sole (Lepidopsetta polyxystra Orr and Matarese) (15-150 mm TL) were conducted to examine relationships between sediment preference, burial performance, and general morphological characteristics. Both species demonstrated significant size-dependent changes in sediment choices during the first year of life. Highest sediment selectivity occurred in the smallest individuals of both species. There was a strong positive relationship between sediment choice and ability to bury quickly and completely, although the choices made by rock sole were less specific than those of comparably sized halibut and were less closely concordant with burial capability. In both species, fish >80 mm TL were relatively nonselective, except that they avoided sediments with the largest grain size (i.e., granules and pebbles). Pacific halibut have narrower, more powerful bodies than rock sole and were stronger burrowers than rock sole. Rock sole were more cryptic than halibut in general locomotion and color-matching capability, and appear to depend to a lesser extent on burial for survival than do halibut. Association with sediment is the first line of defense for juvenile flatfishes, and the relationships shift rapidly with fish size during the first year of benthic life. Therefore, habitat descriptions and models for young post-settlement, flatfishes need to be made for narrow size classes. Published by Elsevier Science B.V. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fisheries Behav Ecol Program, Newport, OR 97365 USA. RP Stoner, AW (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fisheries Behav Ecol Program, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 32 TC 41 Z9 41 U1 1 U2 8 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 8 PY 2003 VL 282 IS 1-2 BP 85 EP 101 AR PII S0022-0981(02)00447-1 DI 10.1016/S0022-0981(02)00447-1 PG 17 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 635UM UT WOS:000180417900006 ER PT J AU Gasso, S Hegg, DA AF Gasso, S Hegg, DA TI On the retrieval of columnar aerosol mass and CCN concentration by MODIS SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE CCN; aerosol mass; validation; MODIS ID MID-ATLANTIC COAST; CHARACTERIZATION EXPERIMENT ACE-2; OBSERVATIONAL EXPERIMENT TARFOX; MARINE BOUNDARY-LAYER; SCALE AIR-POLLUTION; AIRBORNE IN-SITU; OPTICAL-PROPERTIES; SIZE-DISTRIBUTION; UNITED-STATES; TROPOSPHERIC AEROSOL AB A parameterization is introduced for the derivation of columnar aerosol mass concentration (AMC) and cloud condensation nucleus concentration (CCNC) from the primary aerosol products of Moderate-Resolution Imaging Spectroradiometer (MODIS). The method relies on the scaling between AMC and optical depth with a proportionality constant dependent on MODIS-derived r(eff), eta (contribution of the accumulation mode radiance to the total radiance), ambient RH, and an assumed constant aerosol composition. The CCNC is derived from a parameterization of concentration as a function of the retrieved aerosol volume. By comparing with in situ data, it is shown that retrievals in dry ambient conditions (dust) are improved when using a proportionality constant dependent on r(eff) and eta obtained in the same pixel. In high-humidity environments, the improvement in the new method is inconclusive because of the difficulty in accounting for the uneven vertical distribution of relative humidity. Additionally, two detailed comparisons of AMC and CCNC retrieved by the MODIS Airborne Simulator (MAS) algorithm and the new method are shown. The new method and MAS retrievals of AMC are within the same order of magnitude with respect to the in situ measurements of aerosol mass. However, the proposed method is closer to the in situ measurements than the MODIS retrievals. The retrievals of CCNC are also within the same order of magnitude for both methods. Finally, the new method is applied to an actual MODIS retrieval. Although no in situ data is available for comparison, it is shown that the proposed method yields more credible values than the MODIS retrievals. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. EM santiago@climate.gsfc.nasa.gov RI Gasso, Santiago/H-9571-2014 OI Gasso, Santiago/0000-0002-6872-0018 NR 82 TC 24 Z9 24 U1 1 U2 7 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 8 PY 2003 VL 108 IS D1 AR 4010 DI 10.1029/2002JD002382 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655LH UT WOS:000181553400005 ER PT J AU Wang, PH Minnis, P Wielicki, BA Wong, TM Cess, RD Zhang, MH Vann, LB Kent, GS AF Wang, PH Minnis, P Wielicki, BA Wong, TM Cess, RD Zhang, MH Vann, LB Kent, GS TI Characteristics of the 1997/1998 El Nino cloud distributions from SAGE II observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE El Nino; clouds; climate; remote sensing ID TROPOPAUSE REGION; TROPICAL PACIFIC; SATELLITE; MODEL; REANALYSIS; RADIATION; CHEMISTRY; AEROSOL; DATASET; BUDGET AB The present study examines the characteristics of cloud distributions with emphasis on cloud longwave radiative forcing (CLRF) during the peak of the 1997/1998 El Nino in relation to climatological conditions, based on measurements from the Stratospheric Aerosol and Gas Experiment (SAGE) II. The observed distinct cloud occurrence and CLRF during this unusual 1997/1998 El Nino constitutes a unique data set for validating and improving cloud-radiation-climate interactions in general circulation and climate models. Using the solar occultation technique, the SAGE II satellite instrument is capable of providing measurements with a 1-km vertical resolution facilitating the analysis with sufficient vertical as well as near global scale (70degreesS-70degreesN) details. The present study indicates (1) above normal high-altitude opaque cloud occurrence over the eastern tropical Pacific and an opposite situation over the Pacific warm pool, leading to a distribution of the cumulative opaque cloud anomalies above 3 km generally consistent with the pattern of observed tropical sea surface temperature and precipitation anomalies; (2) a similar behavior in the subvisual cloud distributions near the tropical tropopause; (3) a zonally averaged cloud distribution that is characterized by reduced opaque clouds at low latitudes, except in the southern tropics below 10 km, and by enhanced opaque clouds at high latitudes, along with increased subvisual clouds in the southern tropics and decreased subvisual clouds in the northern subtropics in the upper troposphere; and (4) a geographic distribution of model-calculated CLRF anomalies that resembles closely that inferred from the Earth Radiation Budget Experiment and the Clouds and the Earth's Radiant Energy System. A discussion on the influence of the El Nino on large-scale mean tropospheric circulations is also provided. C1 NASA, STC, LaRC, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23665 USA. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. RP Wang, PH (reprint author), NASA, STC, LaRC, MS 475, Hampton, VA 23681 USA. EM p.wang@larc.nasa.gov; p.minnis@larc.nasa.gov; b.a.wielicki@larc.nasa.gov; takmeng.wong@larc.nasa.gov; rcess@notes.cc.sunysb.edu; mzhang@notes.cc.sunysb.edu; l.b.vann@larc.nasa.gov; g.s.kent@larc.nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 43 TC 16 Z9 16 U1 0 U2 1 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 8 PY 2003 VL 108 IS D1 AR 4009 DI 10.1029/2002JD002501 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 655LH UT WOS:000181553400007 ER PT J AU Rex, M Salawitch, RJ Santee, ML Waters, JW Hoppel, K Bevilacqua, R AF Rex, M Salawitch, RJ Santee, ML Waters, JW Hoppel, K Bevilacqua, R TI On the unexplained stratospheric ozone losses during cold Arctic Januaries SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID IN-SITU MEASUREMENTS; POLAR VORTEX; CLO DIMER; WINTER; DEPLETION; BRO; PHOTOCHEMISTRY; PROFILE; RATES; MODEL AB Using a combination of data from Match, POAM II, POAM III and MLS we show that the chemical loss rate of Arctic O-3 during January of four cold winters (1992, 1995, 1996, and 2000) is consistently faster than can be accounted for by assuming complete activation of reactive chlorine and standard reaction kinetics. However, O-3 loss rates measured during late February and early March 1996 are shown to be consistent with observations of ClO. The faster than expected O-3 loss rates during January are shown to occur when air parcels are illuminated at high solar zenith angles (SZAs between similar to85 and 94degrees), and to result in cumulative O-3 loss of similar to0.5 ppmv. The cause of the rapid January O-3 loss is unclear, but may be related to a photolytic process at high SZA that is poorly represented by current photochemical models. C1 Alfred Wegener Inst Polar & Marine Res, Potsdam, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. USN, Res Lab, Washington, DC 20375 USA. RP Rex, M (reprint author), Alfred Wegener Inst Polar & Marine Res, Potsdam, Germany. RI Rex, Markus/A-6054-2009; Salawitch, Ross/B-4605-2009 OI Rex, Markus/0000-0001-7847-8221; Salawitch, Ross/0000-0001-8597-5832 NR 23 TC 33 Z9 34 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 7 PY 2003 VL 30 IS 1 AR 1008 DI 10.1029/2002GL016008 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 655GR UT WOS:000181543400004 ER PT J AU Doran, PT Fritsen, CH McKay, CP Priscu, JC Adams, EE AF Doran, PT Fritsen, CH McKay, CP Priscu, JC Adams, EE TI Formation and character of an ancient 19-m ice cover and underlying trapped brine in an "ice-sealed" east Antarctic lake SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MCMURDO DRY VALLEYS; HOARE; TEMPERATURE; OASIS; LIFE AB Lake Vida, one of the largest lakes in the McMurdo Dry Valleys of Antarctica, was previously believed to be shallow (<10 m) and frozen to its bed year-round. New ice-core analysis and temperature data show that beneath 19 m of ice is a water column composed of a NaCl brine with a salinity seven times that of seawater that remains liquid below -10degreesC. The ice cover thickens at both its base and surface, sealing concentrated brine beneath. The ice cover is stabilized by a negative feedback between ice growth and the freezing-point depression of the brine. The ice cover contains frozen microbial mats throughout that are viable after thawing and has a history that extends to at least 2,800 C-14 years B.P., suggesting that the brine has been isolated from the atmosphere for as long. To our knowledge, Lake Vida has the thickest subaerial lake ice cover recorded and may represent a previously undiscovered end-member lacustrine ecosystem on Earth. C1 Univ Illinois, Dept Earth & Environm Sci, Chicago, IL 60607 USA. Desert Res Inst, Div Earth & Ecosyst Sci, Reno, NV 89512 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Montana State Univ, Bozeman, MT 59717 USA. Montana State Univ, Dept Civil Engn, Bozeman, MT 59717 USA. RP Doran, PT (reprint author), Univ Illinois, Dept Earth & Environm Sci, 845 W Taylor St,MS 186, Chicago, IL 60607 USA. NR 28 TC 40 Z9 42 U1 0 U2 18 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 7 PY 2003 VL 100 IS 1 BP 26 EP 31 DI 10.1073/pnas.222680999 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 633WG UT WOS:000180307100007 PM 12518052 ER PT J AU Yang, QG Seo, J Creekmore, S Temple, D Mott, A Min, NK Yoo, K Kim, SY Jung, SS AF Yang, QG Seo, J Creekmore, S Temple, D Mott, A Min, NK Yoo, K Kim, SY Jung, SS TI Distortions in Z-scan spectroscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID SINGLE-BEAM AB The sample imperfection induced distortions in the closed Z-scan curve are analyzed. It is found that both the magnitudes of the peak and valley transmittances and the shape of the curve are distorted significantly by the inhomogeneous thickness, the nonuniform nonlinearity, and the curved surfaces of the sample. The results suggest that the I-scan method is a more practical choice for the measurement of the third-order nonlinear susceptibility of an inhomogeneous sample. (C) 2003 American Institute of Physics. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. USA, Res Lab, Adelphi, MD 20783 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sogang Univ, Dept Chem Engn, Thermodynam & Green Proc Lab, Seoul 121742, South Korea. Korea Res Inst Stand & Sci, Taejon 305600, South Korea. RP Seo, J (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. NR 5 TC 20 Z9 20 U1 1 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 6 PY 2003 VL 82 IS 1 BP 19 EP 21 DI 10.1063/1.1535264 PG 3 WC Physics, Applied SC Physics GA 630WV UT WOS:000180134100007 ER PT J AU Walsh, P Omeltchenko, A Kalia, RK Nakano, A Vashishta, P Saini, S AF Walsh, P Omeltchenko, A Kalia, RK Nakano, A Vashishta, P Saini, S TI Nanoindentation of silicon nitride: A multimillion-atom molecular dynamics study SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL FORCE MICROSCOPY; SIMULATION; INDENTATION; FRACTURE; INSTABILITY; PRESSURE; ADHESION; SURFACES; STRESS AB Nanoindentation of crystalline and amorphous silicon nitride films is studied using 10-million-atom molecular dynamics simulations. A rigid pyramid-shaped indenter tip is used. Load-displacement curves are computed and are used to derive hardness and elastic moduli of the simulated crystalline and amorphous films. Computer images of local pressure distributions and configuration snapshots show that plastic deformation in the film extends to regions far from the actual indent. (C) 2003 American Institute of Physics. C1 Univ So Calif, Dept Mat Sci & Engn, Collab Adv Comp & Simulat, Los Angeles, CA 90089 USA. Univ So Calif, Dept Phys & Astron, Los Angeles, CA 90089 USA. Univ So Calif, Dept Comp Sci, Los Angeles, CA 90089 USA. NASA, Numer Aerosp Simulat Facil, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Walsh, P (reprint author), Univ So Calif, Dept Mat Sci & Engn, Collab Adv Comp & Simulat, Los Angeles, CA 90089 USA. EM priyav@usc.edu NR 25 TC 42 Z9 42 U1 1 U2 14 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 6 PY 2003 VL 82 IS 1 BP 118 EP 120 DI 10.1063/1.1535263 PG 3 WC Physics, Applied SC Physics GA 630WV UT WOS:000180134100040 ER PT J AU Shearer, CK Righter, K AF Shearer, CK Righter, K TI Behavior of tungsten and hafnium in silicates: A crystal chemical basis for understanding the early evolution of the terrestrial planets SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORE FORMATION; ORIGIN; MOON; DIFFERENTIATION; CONSTRAINTS; VOLCANISM; SYSTEM; MODEL AB The short-lived isotopic system involving the decay of Hf-182 to W-182 (half life of 9 Ma) has been used to establish a time-scale for planetary assembly and core formation. The W isotope signature of lunar and martian basalts appears to be correlated to characteristics of their source. On the Moon, the small amount of excess W-182 is associated with basalts that may be derived from an ilmenite- and clinopyroxene-bearing mantle that was produced during late-stages of lunar magma ocean crystallization. On Mars, excess W-182 is associated with a depleted mantle source. Our experimental measurements for the partitioning behavior of Hf and W between silicates and melt suggest that the early fractionation of Hf from W by phases such as ilmenite, high-Ca clinopyroxene, and garnet may be significant enough to account for the generation of all or part of the radiogenic W signatures in the mantle sources for these basalts. The duration and nature of early mantle differentiation events on the Moon and Mars may be calculated by combining Hf-W fractionation with the extent of radiogenic W enrichment. C1 Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Shearer, CK (reprint author), Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. NR 21 TC 6 Z9 6 U1 2 U2 8 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 4 PY 2003 VL 30 IS 1 AR 1007 DI 10.1029/2002GL015523 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 654KF UT WOS:000181495300001 ER PT J AU Bridges, JC Seabrook, AM Rothery, DA Kim, JR Pillinger, CT Sims, MR Golombek, MP Duxbury, T Head, JW Haldemann, AFC Mitchell, KL Muller, JP Lewis, SR Moncrieff, C Wright, IP Grady, MM Morley, JG AF Bridges, JC Seabrook, AM Rothery, DA Kim, JR Pillinger, CT Sims, MR Golombek, MP Duxbury, T Head, JW Haldemann, AFC Mitchell, KL Muller, JP Lewis, SR Moncrieff, C Wright, IP Grady, MM Morley, JG TI Selection of the landing site in Isidis Planitia of Mars probe Beagle 2 SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Isidis; Beagle 2; Mars Lander; Mars Express ID ORBITER LASER ALTIMETER; THERMAL EMISSION SPECTROMETER; BASALTIC TUFF RINGS; GLOBAL SURVEYOR; GROUND ICE; MARTIAN TOPOGRAPHY; CINDER CONES; LAVA FLOWS; MOLA DATA; PATHFINDER AB This paper describes selection and characterization of the landing site for the Mars 2004 Beagle 2 mission. The site is within Isidis Planitia between 10degrees-12N, 266degrees-274degreesW, centered at 11.6degreesN, 269.5degreesW. This is at low elevation (-3600 to -3900 m MOLA), is flat (MOLA RMS slope=0.57degrees), radar data suggest a smoother surface at decimeter to meter scales than the Pathfinder site and it has a moderate rock abundance (2-17%, mean 11%). In addition to this, Isidis shows evidence for concentration and remobilization of volatiles. In particular, the basin contains conical landforms. We favor models involving the formation of tuff cones during magma-ice interaction. Structures identified as dykes in MOC images may be remnants of magma conduits. The pattern of bulk thermal inertia in Isidis (higher values of 500 Jm(-2) s(-0.5) K(-1) around the SW-S-E margin decreasing toward the center and north) suggests that an influx of sediment spread from the Noachian areas around the southern half of the basin over the basin floor. The coarse, higher thermal inertia material was deposited closest to the sediment source. The variable state of erosion of the tuff cones suggests that they formed intermittently over a long period of time during Amazonian and possibly Hesperian epochs. Geologically recent resurfacing of Isidis has also occurred by aeolian processes, and this is shown by a deficit in impact craters <120 m diameter. The proportion of rocky material is predicted to be slightly less than the Viking and Pathfinder sites, but there will probably be more duricrust. C1 Nat Hist Museum, Dept Mineral, London SW7 5BD, England. Open Univ, PSSRI, Milton Keynes MK7 6AA, Bucks, England. Open Univ, Dept Earth Sci, Milton Keynes MK7 6AA, Bucks, England. UCL, Dept Geomatic Engn, London, England. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Lancaster, Dept Environm Sci, Lancaster, England. Univ Oxford, Dept Phys, AOPP, Oxford OX1 3PU, England. Nat Hist Museum, Dept Zool, London SW7 5BD, England. RP Bridges, JC (reprint author), Nat Hist Museum, Dept Mineral, London SW7 5BD, England. OI Muller, Jan-Peter/0000-0002-5077-3736; Lewis, Stephen/0000-0001-7237-6494 NR 88 TC 31 Z9 31 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-PLANET JI J. Geophys. Res.-Planets PD JAN 4 PY 2003 VL 108 IS E1 AR 5001 DI 10.1029/2001JE001820 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 654MV UT WOS:000181501400001 ER PT J AU Christian, HJ Blakeslee, RJ Boccippio, DJ Boeck, WL Buechler, DE Driscoll, KT Goodman, SJ Hall, JM Koshak, WJ Mach, DM Stewart, MF AF Christian, HJ Blakeslee, RJ Boccippio, DJ Boeck, WL Buechler, DE Driscoll, KT Goodman, SJ Hall, JM Koshak, WJ Mach, DM Stewart, MF TI Global frequency and distribution of lightning as observed from space by the Optical Transient Detector SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE lightning; thunderstorm; atmospheric electricity; convection; climatology; remote sensing ID EL-NINO EVENT; SCHUMANN RESONANCE; IMAGING SENSOR; UNITED-STATES; CROSS-SENSOR; CLOUD; VARIABILITY; RAINFALL; ATLANTIC; AFRICA AB The Optical Transient Detector (OTD) is a space-based instrument specifically designed to detect and locate lightning discharges as it orbits the Earth. This instrument is a scientific payload on the MicroLab-1 satellite that was launched into a 70degrees inclination low Earth orbit in April 1995. Given the orbital trajectory of the satellite, most regions of the Earth are observed by the OTD instrument more than 400 times during a 1 year period, and the average duration of each observation is 2 min. The OTD instrument optically detects lightning flashes that occur within its 1300x1300 km(2) field of view during both day and night conditions. A statistical examination of OTD lightning data reveals that nearly 1.4 billion flashes occur annually over the entire Earth. This annual flash count translates to an average of 44+/-5 lightning flashes (intracloud and cloud-to-ground combined) occurring around the globe every second, which is well below the traditional estimate of 100 fl s(-1) that was derived in 1925 from world thunder day records. The range of uncertainty for the OTD global totals represents primarily the uncertainty (and variability) in the flash detection efficiency of the instrument. The OTD measurements have been used to construct lightning climatology maps that demonstrate the geographical and seasonal distribution of lightning activity for the globe. An analysis of this annual lightning distribution confirms that lightning occurs mainly over land areas, with an average land/ocean ratio of similar to10:1. The Congo basin, which stands out year-round, shows a peak mean annual flash density of 80 fl km(-2) yr(-1) in Rwanda, and includes an area of over 3 million km(2) exhibiting flash densities greater than 30 fl km(-2) yr(-1) (the flash density of central Florida). Lightning is predominant in the northern Atlantic and western Pacific Ocean basins year-round where instability is produced from cold air passing over warm ocean water. Lightning is less frequent in the eastern tropical Pacific and Indian Ocean basins where the air mass is warmer. A dominant Northern Hemisphere summer peak occurs in the annual cycle, and evidence is found for a tropically driven semiannual cycle. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. Niagara Univ, Niagara, NY 14109 USA. CSC Huntsville, Huntsville, AL 35805 USA. RP Christian, HJ (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. NR 48 TC 508 Z9 534 U1 8 U2 63 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 3 PY 2003 VL 108 IS D1 AR 4005 DI 10.1029/2002JD002347 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654LN UT WOS:000181498500003 ER PT J AU Santer, BD Sausen, R Wigley, TML Boyle, JS AchutaRao, K Doutriaux, C Hansen, JE Meehl, GA Roeckner, E Ruedy, R Schmidt, G Taylor, KE AF Santer, BD Sausen, R Wigley, TML Boyle, JS AchutaRao, K Doutriaux, C Hansen, JE Meehl, GA Roeckner, E Ruedy, R Schmidt, G Taylor, KE TI Behavior of tropopause height and atmospheric temperature in models, reanalyses, and observations: Decadal changes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE tropopause height; tropospheric temperatures; stratospheric temperatures; climate modeling; microwave sounding unit ID CLIMATE-CHANGE SIMULATIONS; TROPICAL TROPOPAUSE; GREENHOUSE-GAS; 20TH-CENTURY TEMPERATURE; FINGERPRINT DETECTION; THERMAL STRUCTURE; OZONE DEPLETION; AEROSOL; TRENDS; ATTRIBUTION AB We examine changes in tropopause height, a variable that has hitherto been neglected in climate change detection and attribution studies. The pressure of the lapse rate tropopause, p(LRT), is diagnosed from reanalyses and from integrations performed with coupled and uncoupled climate models. In the National Centers for Environmental Prediction (NCEP) reanalysis, global-mean p(LRT) decreases by 2.16 hPa/decade over 1979-2000, indicating an increase in the height of the tropopause. The shorter European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis has a global-mean p(LRT) trend of -1.13 hPa/decade over 1979-1993. Simulated p(LRT) trends over the past several decades are consistent with reanalysis results. Superimposed on the overall increase in tropopause height in models and reanalyses are pronounced height decreases following the eruptions of El Chichon and Pinatubo. Interpreting these p(LRT) results requires knowledge of both T(z), the initial atmospheric temperature profile, and DeltaT(z), the change in this profile in response to external forcing. T( z) has a strong latitudinal dependence, as does DeltaT( z) for forcing by well-mixed greenhouse gases and stratospheric ozone depletion. These dependencies help explain why overall tropopause height increases in reanalyses and observations are amplified toward the poles. The pronounced increases in tropopause height in the climate change integrations considered here indicate that even AGCMs with coarse vertical resolution can resolve relatively small externally forced changes in tropopause height. The simulated decadal-scale changes in p(LRT) are primarily thermally driven and are an integrated measure of the anthropogenically forced warming of the troposphere and cooling of the stratosphere. Our algorithm for estimating p(LRT) (based on a thermal definition of tropopause height) is sufficiently sensitive to resolve these large-scale changes in atmospheric thermal structure. Our results indicate that the simulated increase in tropopause height over 1979-1997 is a robust, zero-order response of the climate system to forcing by well-mixed greenhouse gases and stratospheric ozone depletion. At the global-mean level, we find agreement between the simulated decadal-scale p(LRT) changes and those estimated from reanalyses. While the agreement between simulated p(LRT) changes and those in NCEP is partly fortuitous (due to excessive stratospheric cooling in NCEP), it is also driven by real pattern similarities. Our work illustrates that changes in tropopause height may be a useful "fingerprint'' of human effects on climate and are deserving of further attention. C1 Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Zentrum Luft & Raumfahrt, Inst Phys Atmosphere, D-82234 Wessling, Germany. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. RP Santer, BD (reprint author), Lawrence Livermore Natl Lab, PCMDI, POB 808,Mail Stop L-103, Livermore, CA 94550 USA. EM santer1@llnl.gov; robert.sausen@dlr.de; wigley@ucar.edu; boyle5@llnl.gov; achutarao1@llnl.gov; doutriaux1@llnl.gov; jhansen@giss.nasa.gov; meehl@ucar.edu; roeckner@dkrz.de; cdrar@ipcc2.giss.nasa.gov; gschmidt@giss.nasa.gov; taylor13@llnl.gov RI Wigley, Tom/B-4705-2008; Taylor, Karl/F-7290-2011; Santer, Benjamin/F-9781-2011; Schmidt, Gavin/D-4427-2012 OI Taylor, Karl/0000-0002-6491-2135; Schmidt, Gavin/0000-0002-2258-0486 NR 65 TC 97 Z9 108 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 3 PY 2003 VL 108 IS D1 AR 4002 DI 10.1029/2002JD002258 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654LN UT WOS:000181498500002 ER PT J AU Zhou, L Kaufmann, RK Tian, Y Myneni, RB Tucker, CJ AF Zhou, L Kaufmann, RK Tian, Y Myneni, RB Tucker, CJ TI Relation between interannual variations in satellite measures of northern forest greenness and climate between 1982 and 1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE NDVI; climate; greening; temperature; statistical techniques ID LEAF-AREA INDEX; VEGETATION INDEX; TERRESTRIAL ECOSYSTEMS; ATMOSPHERIC CO2; PLANT-GROWTH; TIME-SERIES; CARBON SINK; AVHRR DATA; TEMPERATURE; RESOLUTION AB This paper analyzes the relation between satellite-based measures of vegetation greenness and climate by land cover type at a regional scale (2degrees x 2degrees grid boxes) between 1982 and 1999. We use the normalized difference vegetation index (NDVI) from the Global Inventory Monitoring and Modeling Studies (GIMMS) data set to quantify climate-induced changes in terrestrial vegetation. Climatic conditions are represented with monthly data for land surface air temperature and precipitation. The relation between NDVI and the climate variables is represented using a quadratic specification, which is consistent with the notion of a physiological optimum. The effects of spatial heterogeneity and unobserved variables are estimated with specifications and statistical techniques that allow coefficients to vary among grid boxes. Using this methodology, we are able to estimate statistically meaningful relations between NDVI and climate during spring, summer, and autumn for forests between 40degreesN and 70degreesN in North America and Eurasia. Of the variables examined, changes in temperature account for the largest fraction of the change in NDVI between the early 1980s and the late 1990s. Changes in stratospheric aerosol optical depth and precipitation have a smaller effect, while artifacts associated with variations in solar zenith angle are negligible. These results indicate that temperature changes between the early 1980s and the late 1990s are responsible for much of the observed increase in satellite measures of northern forest greenness. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Zhou, L (reprint author), Boston Univ, Dept Geog, Boston, MA 02215 USA. EM lmzhou@eas.gatech.edu RI Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012 NR 56 TC 166 Z9 196 U1 4 U2 36 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 3 PY 2003 VL 108 IS D1 AR 4004 DI 10.1029/2002JD002510 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 654LN UT WOS:000181498500004 ER PT J AU Bauschlicher, CW Ricca, A AF Bauschlicher, CW Ricca, A TI Modelling of benzene-1,4-dithiol on a Au(111) surface SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; MOLECULES; TRANSPORT AB The bonding of benzene-1,4-dithiol to a Au(1 1 1) surface is studied using a Au-25-SC6H4SH model. We find that the most favorable structure has the S directly above an An atom, i.e., an on-top site. If the molecule is constrained to be perpendicular to the surface, the on-top site is the least favorable site and the threefold hollow is the most favorable one. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Space Technol Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 14 TC 19 Z9 19 U1 1 U2 6 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 2 PY 2003 VL 367 IS 1-2 BP 90 EP 94 AR PII S0009-2614(02)01626-3 DI 10.1016/S0009-2614(02)01626-3 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 633GB UT WOS:000180273300013 ER PT J AU Gizon, L Duvall, TL Schou, J AF Gizon, L Duvall, TL Schou, J TI Wave-like properties of solar supergranulation SO NATURE LA English DT Article ID TIME-DISTANCE HELIOSEISMOLOGY; COMPRESSIBLE CONVECTION; MAGNETIC FEATURES; ROTATION; EVOLUTION; FIELDS; MODES; FLOWS AB Supergranulation(1,2) on the surface of the Sun is a pattern of horizontal outflows, outlined by a network of small magnetic features, with a distinct scale of 30 million metres and an apparent lifetime of one day. It is generally believed that supergranulation corresponds to a preferred 'cellular' scale of thermal convection; rising magnetic fields are dragged by the outflows and concentrated into 'ropes' at the 'cell' boundaries(3). But as the convection zone is highly turbulent and stratified, numerical modelling has proved to be difficult and the dynamics remain poorly understood. Moreover, there is as yet no explanation for the observation that the pattern appears(4,5) to rotate faster around the Sun than the magnetic features. Here we report observations showing that supergranulation undergoes oscillations and supports waves with periods of 6-9 days. The waves are predominantly prograde, which explains the apparent super-rotation of the pattern. The rotation of the plasma through which the pattern propagates is consistent with the motion of the magnetic network. C1 Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Gizon, L (reprint author), Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. RI Gizon, Laurent/B-9457-2008; Duvall, Thomas/C-9998-2012 NR 18 TC 72 Z9 72 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 2 PY 2003 VL 421 IS 6918 BP 43 EP 44 DI 10.1038/nature01287 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 631JY UT WOS:000180165500030 PM 12511947 ER PT J AU Root, TL Price, JT Hall, KR Schneider, SH Rosenzweig, C Pounds, JA AF Root, TL Price, JT Hall, KR Schneider, SH Rosenzweig, C Pounds, JA TI Fingerprints of global warming on wild animals and plants SO NATURE LA English DT Article AB Over the past 100 years, the global average temperature has increased by approximately 0.6 degreesC and is projected to continue to rise at a rapid rate(1). Although species have responded to climatic changes throughout their evolutionary history(2), a primary concern for wild species and their ecosystems is this rapid rate of change(3). We gathered information on species and global warming from 143 studies for our meta-analyses. These analyses reveal a consistent temperature-related shift, or 'fingerprint', in species ranging from molluscs to mammals and from grasses to trees. Indeed, more than 80% of the species that show changes are shifting in the direction expected on the basis of known physiological constraints of species. Consequently, the balance of evidence from these studies strongly suggests that a significant impact of global warming is already discernible in animal and plant populations. The synergism of rapid temperature rise and other stresses, in particular habitat destruction, could easily disrupt the connectedness among species and lead to a reformulation of species communities, reflecting differential changes in species, and to numerous extirpations and possibly extinctions. C1 Stanford Univ, Inst Int Studies, Ctr Environm Sci & Policy, Stanford, CA 94305 USA. Amer Bird Conservancy, Boulder, CO 80301 USA. Michigan State Univ, Dept Fisheries & Wildlife, E Lansing, MI 48824 USA. Stanford Univ, Dept Biol Sci, Stanford, CA 94305 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Monteverde Cloud Forest Preserve & Trop Sci Ctr, Golden Toad Lab Conservat, Santa Elena, Puntarenas, Costa Rica. RP Root, TL (reprint author), Stanford Univ, Inst Int Studies, Ctr Environm Sci & Policy, Stanford, CA 94305 USA. NR 14 TC 2105 Z9 2281 U1 148 U2 2106 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 2 PY 2003 VL 421 IS 6918 BP 57 EP 60 DI 10.1038/nature01333 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 631JY UT WOS:000180165500035 PM 12511952 ER PT S AU Schepis, JP McClendon, MW Webb, MM Zewari, SW Hylan, JE Barthelmy, MP MacKenty, J AF Schepis, JP McClendon, MW Webb, MM Zewari, SW Hylan, JE Barthelmy, MP MacKenty, J BE Harris, RA TI Two cryogenic mechanisms for earth based infrared astronomy SO 10TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Space Mechanisms and Tribology Symposium CY SEP 24-26, 2003 CL SAN SEBASTIAN, SPAIN SP European Space Agcy, Fundac INASMET, CNES, SENER, ProESPacio, INTA AB The Infrared Multi-Object Spectrograph (IRMOS) is a ground based, low budget, principle investigator class, cryogenic instrument for IR astronomy. The instrument envelope and optomechanical designs were defined prior to beginning mechanism detailed designs, so serious volumetric constraints were encountered during the advanced design phase. This fact and the high precision requirements, room temperature and cryogenic operation, and budgetary constraints led to simple, robust and relatively cost effective designs. We describe the mechanism requirements, analysis and design. Without time for a development program, several significant assumptions proved incorrect and the lessons learned will also be discussed. C1 NASA, Goddard Space Flight Ctr, Mech Syst Div, Greenbelt, MD 20771 USA. RP Schepis, JP (reprint author), NASA, Goddard Space Flight Ctr, Mech Syst Div, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-834-4 J9 ESA SP PUBL PY 2003 VL 524 BP 341 EP 345 PG 5 WC Engineering, Aerospace; Engineering, Mechanical; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BX94T UT WOS:000186910000050 ER PT S AU Budinoff, JG AF Budinoff, JG BE Harris, RA TI Precision select mechanisms for the GLAS & SOLSE2 instruments SO 10TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Space Mechanisms and Tribology Symposium CY SEP 24-26, 2003 CL SAN SEBASTIAN, SPAIN SP European Space Agcy, Fundac INASMET, CNES, SENER, ProESPacio, INTA AB The Geoscience Laser Altimeter System (GLAS) instrument had requirements for a 2-position mechanism to rotate mirrors into and out of the optical path of the altimetry detectors and the lasers. The Solar Ozone Limb Sounding Experiment II (SOLSE2) instrument had a similar requirement of rotating a visible (VIS) or ultraviolet (UV) filter into the instrument optical path. Both GLAS and SOLSE2 had similar operational and survival environments and lifetime requirements. A novel, precision rotational latching mechanism was designed to fulfill the needs of both missions. The GLAS instrument had driving stability and repeatability requirements, such that if the mechanism met these stringent requirements, it would more than surpass the required performance for the SOLSE2 mechanism. The resulting mechanism, referred to as a "select mechanism" since it allows selection between 2 positions, was successfully designed and implemented for both missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Budinoff, JG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-834-4 J9 ESA SP PUBL PY 2003 VL 524 BP 347 EP 351 PG 5 WC Engineering, Aerospace; Engineering, Mechanical; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BX94T UT WOS:000186910000051 ER PT S AU Ahmed, R Johnston, AS Garrison, JC Gaines, JL Waggoner, JD AF Ahmed, R Johnston, AS Garrison, JC Gaines, JL Waggoner, JD BE Harris, RA TI Design and demonstration of Bolt Retractor separation system for X-38 Deorbit Propulsion Stage SO 10TH EUROPEAN SPACE MECHANISMS AND TRIBOLOGY SYMPOSIUM, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 10th European Space Mechanisms and Tribology Symposium CY SEP 24-26, 2003 CL SAN SEBASTIAN, SPAIN SP European Space Agcy, Fundac INASMET, CNES, SENER, ProESPacio, INTA AB A separation system was designed for the X-38 experimental crew return vehicle program to allow the Deorbit Propulsion Stage (DPS) to separate from the X-38 lifting body during reentry operations. The configuration chosen was a spring-loaded plunger, known as the Bolt Retractor Subsystem (BRS), that retracts each of the six DPS-to-lifting body attachment bolts across the interface plane after being triggered by a separation nut mechanism. The system was designed to function on the ground in an atmospheric environment as well as in space. The BRS provides the same functionality as that of a completely pyrotechnic shear separation system that would normally be considered ideal for this application, but at a much lower cost. This system also could potentially be applied to future space station crew return vehicles. The design goal of 40 ms retraction time was successfully met in a series of demonstrations performed at the NASA Marshall Space Flight Center's Pyrotechnic Shock Facility (PSF) and Flight Robotics Laboratory (FRL). It must be emphasized that a full-scale test series was not performed on the BRS due to program schedule and cost constraints. C1 NASA, George C Marshall Space Flight Ctr, MSFC, AL 35812 USA. RP Ahmed, R (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Code ED23, MSFC, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-834-4 J9 ESA SP PUBL PY 2003 VL 524 BP 371 EP 377 PG 7 WC Engineering, Aerospace; Engineering, Mechanical; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BX94T UT WOS:000186910000056 ER PT B AU Lutz, RR Mikulski, IC AF Lutz, RR Mikulski, IC GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Resolving requirements discovery in testing and operations SO 11TH IEEE INTERNATIONAL REQUIREMENTS ENGINEERING CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Requirement Engineering Conference CY SEP 08-12, 2003 CL MONTEREY, CA SP IEEE Comp Soc, IEEE Comp Soc Tech Council Software Engn, Univ Twente, Dept Comp Sci, Requirements Engn Journal, ACM SIGSOFT, IFIP Working Grp 2 9, Int Council Syst Engn AB This paper describes the results of an investigation into requirements discovery during testing and operations. Requirements discovery includes both new requirements and new knowledge regarding existing requirements. Analysis of anomaly reports shows that many of the anomalies that occur during these phases involve requirements discovery. Previous work by the authors. identified four common mechanisms for requirements discovery and resolution during testing. The results reported here extend that work in two ways: (1) to show that very similar requirements-discovery mechanisms are at work in both testing and operations, and (2) to evaluate the requirements-discovery mechanisms against experience with seven additional systems. The paper discusses the consequences of these classifications and results in terms of reducing requirements-based defects in critical, embedded systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lutz, RR (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1980-6 PY 2003 BP 33 EP 41 PG 9 WC Computer Science, Software Engineering SC Computer Science GA BX62C UT WOS:000185894600006 ER PT B AU Feather, MS Menzies, T Connelly, JR AF Feather, MS Menzies, T Connelly, JR GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Relating practitioner needs to research activities SO 11TH IEEE INTERNATIONAL REQUIREMENTS ENGINEERING CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 11th IEEE International Requirement Engineering Conference CY SEP 08-12, 2003 CL MONTEREY, CA SP IEEE Comp Soc, IEEE Comp Soc Tech Council Software Engn, Univ Twente, Dept Comp Sci, Requirements Engn Journal, ACM SIGSOFT, IFIP Working Grp 2 9, Int Council Syst Engn AB Many organizations look to research to yield new and improved products and practices. Connecting practitioners who have the need for research results to the researchers producing those results is important to guiding research and utilizing its results. Likewise, connecting researchers working on related topics to one another, and connecting practitioners with related needs to one another, is important to establishing communities of shared interests. We demonstrate an approach that helps identify fruitful such connections. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Feather, MS (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1980-6 PY 2003 BP 352 EP 352 PG 1 WC Computer Science, Software Engineering SC Computer Science GA BX62C UT WOS:000185894600052 ER PT S AU Winker, D AF Winker, D BE Werner, C Oppel, UG TI Accounting for multiple scattering in retrievals from space lidar SO 12TH INTERNATIONAL WORKSHOP ON LIDAR MULTIPLE SCATTERING EXPERIMENTS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 12th International Workshop on Lidar Multiple Scattering Experiments CY SEP 10-12, 2002 CL GERMAN AEROSP CTR, OBERPFAFFENHOFEN, GERMANY SP Inst Atmospher Phys, DLR HO GERMAN AEROSP CTR DE spaceborne lidar; multiple scattering; aerosols; clouds; extinction; CALIPSO ID MONTE-CARLO CALCULATIONS; SINGLE-SCATTERING; CIRRUS CLOUDS; ICE CRYSTALS; RETURNS; LITE AB Multiple scattering effects on signals from space lidar are significant and must be accounted for in the retrieval of aerosol and cloud extinction. It is shown that a simple parameterization of multiple scattering allows one to account for multiple scattering effects using a slightly modified form of a commonly used single-scatter retrieval solution. All orders of scattering are considered in the development of parameterizations appropriate for the CALIPSO lidar. Applications to aerosol and cloud retrievals are discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Winker, D (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 20 TC 43 Z9 45 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4865-6 J9 P SOC PHOTO-OPT INS PY 2003 VL 5059 BP 128 EP 139 DI 10.1117/12.512352 PG 12 WC Remote Sensing; Optics; Physics, Applied SC Remote Sensing; Optics; Physics GA BW54W UT WOS:000182379000014 ER PT B AU Chao, WC Chen, BD Tao, WK AF Chao, WC Chen, BD Tao, WK GP ams TI Tropical cyclogenesis as a catastrophe SO 14TH CONFERENCE ON ATMOSPHERIC AND OCEANIC FLUID DYNAMICS LA English DT Proceedings Paper CT 14th Conference on Atmospheric and Oceanic Fluid Dynamics CY JUN 09-13, 2003 CL SAN ANTONIO, TX SP Amer Meteorol Soc ID MODEL C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Chao, WC (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 157 EP 160 PG 4 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA BBB59 UT WOS:000224565100045 ER PT S AU Eberspeaker, PJ Gregory, DD Smith, IS AF Eberspeaker, PJ Gregory, DD Smith, IS BE Warmbein, B TI An overview of the NASA Sounding Rockets and Balloon Programs SO 16TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 16th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY JUN 02-05, 2003 CL ST GALLEN, SWITZERLAND SP European Space Agcy AB The U. S. National Aeronautics and Space Administration (NASA) Sounding Rockets and Balloon Programs conduct a total of 50 to 60 missions per year in support of the NASA scientific community. The NASA Sounding Rockets Program supports the science community by integrating their experiments into the sounding rocket payload, and providing both the rocket vehicle and launch operations. Sounding rockets provide an effective way to make in situ observations from 50 to 1500 km in altitude with unique coverage of the altitude regime between 50 km and 130 km, which is not accessible by balloons or satellites. The NASA Balloon Program continues to develop new technologies in its support of the scientific ballooning community. The Long Duration Balloon (LDB) is a prominent aspect of the program with campaigns supported in both the northern and southern hemispheres. NASA continues with its development of an Ultra Long Duration Balloon (ULDB) capability for the support of 100-day missions. The Program continues to introduce new technology and improvements in flight systems, ground systems and operations capabilities. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Eberspeaker, PJ (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-840-9 J9 ESA SP PUBL PY 2003 VL 530 BP 53 EP 59 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BX97A UT WOS:000187062200007 ER PT S AU Merritt, B Hottman, S Hansen, K Cathey, HM AF Merritt, B Hottman, S Hansen, K Cathey, HM BE Warmbein, B TI The NASA Suborbital Center of Excellence - Preparing the next generation of scientists and engineers (ESA SE-058) SO 16TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 16th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY JUN 02-05, 2003 CL ST GALLEN, SWITZERLAND SP European Space Agcy AB The NASA Suborbital Center of Excellence (SCE) is charting new territory. From an idea to promote science and engineering education and outreach, the SCE is working toward the objective of increasing numbers of college graduates choosing a career in suborbital programs. Educational outreach initiatives for young children to university students are presented. These include hands-on experiments, demonstrations, and suborbital educational materials. Approaches to excite university students to want to pursue these careers through relevant and useful work experiences are also presented. A key component of this is the SCE co-op program. Future programs and initiatives are presented. The SCE is evolving, meeting the needs to promote science and engineering education and outreach. C1 NASA, Goddard Space Flight Ctr, Balloon Program Off, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Merritt, B (reprint author), NASA, Goddard Space Flight Ctr, Balloon Program Off, Wallops Flight Facil, Code 820, Wallops Isl, VA 23337 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-840-9 J9 ESA SP PUBL PY 2003 VL 530 BP 79 EP 84 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BX97A UT WOS:000187062200012 ER PT S AU Ward, PR DeWeese, KD AF Ward, PR DeWeese, KD BE Warmbein, B TI Balloon borne arcsecond pointer feasibility study SO 16TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 16th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY JUN 02-05, 2003 CL ST GALLEN, SWITZERLAND SP European Space Agcy AB A major hurdle in extending the range of experiments for which balloon vehicles are useful has been the imposition of the gondola dynamics on the accuracy with which an instrument can be kept pointed at a celestial target. In this paper, the foundation for a high fidelity controller simulation is presented and it is shown that sub-arcsecond pointing stability can be achieved for a large instrument pointing at an inertial target. The flexibility of the flight train is represented through generalized modal analysis. A multiple controller scheme is introduced with a coarse azimuth pointer and a pitch-yaw gimbal mount for fine pointing. An analysis and demonstration of the necessity in eliminating static friction are provided along with a solution to eliminate static friction from the system dynamics. A control scheme involving linear accelerometers for enhanced disturbance rejection is also presented. This paper establishes that the proposed control strategy can be made robustly stable with significant design margins. Also demonstrated is the efficacy of the proposed system in rejecting disturbances larger than those considered realistic. C1 NASA, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Ward, PR (reprint author), NASA, Wallops Flight Facil, Code 598, Wallops Isl, VA 23337 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-840-9 J9 ESA SP PUBL PY 2003 VL 530 BP 197 EP 205 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BX97A UT WOS:000187062200033 ER PT S AU Kerzhanovich, VV Cutts, JA Hall, JL AF Kerzhanovich, VV Cutts, JA Hall, JL BE Warmbein, B TI Low-cost balloon missions to Mars and Venus SO 16TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 16th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY JUN 02-05, 2003 CL ST GALLEN, SWITZERLAND SP European Space Agcy AB The first successful flight demonstration of aerial deployment of Mars balloon prototypes in June 2002 and of a Venus balloon prototype in 1999 is deemed to be a turning point in the risk assessment of balloon missions. These flight tests as well as preceding development, simulations and tests have brought a better understanding of major influencing factors and proved the feasibility of the concept. A low-cost dedicated or piggyback mission based on this technology could be the first opportunity for planetary balloon missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kerzhanovich, VV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-840-9 J9 ESA SP PUBL PY 2003 VL 530 BP 285 EP 291 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BX97A UT WOS:000187062200048 ER PT S AU Goldberg, RA Fritts, DC Williams, BP Schmidlin, FJ Croskey, CL Mitchell, JD Lubken, FJ Rapp, M Singer, W Latteck, R Blix, TA Friedrich, M Kirkwood, S Mitchell, N Fricke, KH AF Goldberg, RA Fritts, DC Williams, BP Schmidlin, FJ Croskey, CL Mitchell, JD Lubken, FJ Rapp, M Singer, W Latteck, R Blix, TA Friedrich, M Kirkwood, S Mitchell, N Fricke, KH BE Warmbein, B TI The MaCWAVE program to study gravity wave forcing of the polar mesosphere during summer and winter SO 16TH ESA SYMPOSIUM ON EUROPEAN ROCKET AND BALLOON PROGRAMMES AND RELATED RESEARCH, PROCEEDINGS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 16th ESA Symposium on European Rocket and Balloon Programmes and Related Research CY JUN 02-05, 2003 CL ST GALLEN, SWITZERLAND SP European Space Agcy ID MESOPAUSE CIRCULATION; THERMAL STRUCTURE; MOMENTUM FLUX; DYNAMICS; BREAKING AB Gravity waves provide the dominant forcing of the mesosphere and lower thermosphere (MLT) under solstice conditions via energy and momentum transports from lower altitudes and their dissipation in the MLT. Despite this, the quantitative aspects of this important forcing are poorly understood at present. MaCWAVE is an acronym for Mountain and Convective Waves Ascending Vertically. This correlative rocket, ground-based, and satellite program was designed to address these issues with launch sequences into the polar MLT during summer 2002 and winter 2003 conditions. The programs were conducted at the Norwegian Andoya Rocket Range (ARR, 69.3degreesN) in July, 2002, and at the Swedish Rocket Range (ESRANGE, 67.9degreesN) during January, 2003. Correlative instrumentation included the ALOMAR radars and lidars (including the new Weber sodium lidar), ESRANGE RMR lidar, MST and meteor radars (ESRAD and SkiYmet), radiosondes, and TIMED satellite measurements of thermal, wind, and constituent structures. A program description plus preliminary results are discussed here. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Goldberg, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 690, Greenbelt, MD 20771 USA. RI Goldberg, Richard /E-1881-2012; Rapp, Markus/K-6081-2015; OI Rapp, Markus/0000-0003-1508-5900; Latteck, Ralph/0000-0002-0001-7473 NR 19 TC 3 Z9 3 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-840-9 J9 ESA SP PUBL PY 2003 VL 530 BP 345 EP 350 PG 6 WC Engineering, Aerospace; Instruments & Instrumentation; Meteorology & Atmospheric Sciences SC Engineering; Instruments & Instrumentation; Meteorology & Atmospheric Sciences GA BX97A UT WOS:000187062200057 ER PT B AU Pain, B Hancock, B Cunningham, T AF Pain, B Hancock, B Cunningham, T GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI CMOS digital imager design from a system-on-a-chip perspective SO 16TH INTERNATIONAL CONFERENCE ON VLSI DESIGN, PROCEEDINGS LA English DT Proceedings Paper CT 16th International Conference on VLSI Design/2nd International Conference on Embedded Systems Design CY JAN 04-08, 2003 CL NEW DELHI, INDIA SP VLSI Soc India, Govt India, Minist Commun & Informat Technol, IEEE Circuits & Syst Soc, ACM SIGDA, NASSCOM AB Due to substantial mixed analog-digital circuit integration in one chip, CMOS digital imager cannot be considered only as a photoelectric transducer. In this paper, we have identified timing and circuit layout considerations that are critical for implementing a digital CMOS camera-on-a-chip. An optimized binary-scaled tree-topology power routing has been shown to be critical for minimizing chip area and providing low spatial pattern noise. Imaging artifacts due to timing asymmetry has been quantified, and methods for elimination of the artifacts have been demonstrated. The impact of on-chip bias-generation and drive circuits on the on-chip ADC performance has been shown. New timing and circuit layout techniques has been presented for enabling random noise limited performance of a CMOS imager. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Pain, B (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1868-0 PY 2003 BP 395 EP 400 DI 10.1109/ICVD.2003.1183168 PG 6 WC Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BW06X UT WOS:000180780500068 ER PT B AU Fischer, B Schumann, J AF Fischer, B Schumann, J BE Werner, B TI Applying AutoBayes to the analysis of planetary nebulae images SO 18TH IEEE INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 18th IEEE International Conference on Automated Software Engineering CY OCT 06-10, 2003 CL MONTREAL, CANADA SP IEEE Comp Soc, CRIM, ACM SIGART, ACM SIGSOFT AB We take a typical scientific data analysis task, the analysis of planetary nebulae images taken by the Hubble Space Telescope, and describe how program synthesis can be used to generate the necessary analysis programs from high-level models. We describe the AUTOBAYES synthesis system, discuss its fully declarative specification language, and present the automatic program derivation starting with the scientists' original analysis [7]. C1 NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP Fischer, B (reprint author), NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. NR 12 TC 3 Z9 3 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2035-9 PY 2003 BP 337 EP 342 DI 10.1109/ASE.2003.1240333 PG 6 WC Computer Science, Software Engineering SC Computer Science GA BX81Y UT WOS:000186519300045 ER PT B AU Kim, CS Kiris, C Kwak, D AF Kim, CS Kiris, C Kwak, D GP ASME TI Simulation of local blood flow in human brain under altered gravity SO 2003 ADVANCES IN BIOENGINEERING LA English DT Proceedings Paper CT ASME International Mechanical Engineering Congress CY NOV 15-21, 2003 CL Washington, DC SP ASME, Fluid Power Syst & Technol Div, ASME, Micro Elect Mech Syst Div, ASME, Fluids Engn Div, ASME, Bioengn Div, ASME, Appl Mech Div, ASME, Elect & Photon Packaging Div, ASME, Mfg Engn Div, ASME, Adv Energy Syst Div, ASME, Aerosp Div ID CAROTID-ARTERY BIFURCATION; MODEL C1 NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94305 USA. RP Kim, CS (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94305 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3710-6 PY 2003 BP 87 EP 88 PG 2 WC Biophysics; Engineering, Biomedical; Mechanics; Medicine, Research & Experimental SC Biophysics; Engineering; Mechanics; Research & Experimental Medicine GA BAL07 UT WOS:000222660500039 ER PT B AU Frederickson, AR Dennison, JR AF Frederickson, AR Dennison, JR GP IEEE IEEE TI Measurement of conductivity and charge storage in insulators related to spacecraft charging SO 2003 ANNUAL REPORT CONFERENCE ON ELECTRICAL INSULATION AND DIELECTRIC PHENOMENA LA English DT Proceedings Paper CT Annual Conference on Electrical Insulation and Dielectric Phenomena (CEIDP) CY OCT 19-22, 2003 CL ALBUQUERQUE, NM SP IEEE Dielect & Elect Insulat Soc AB Novel methods have been developed to measure conductivity and charge storage in thin film insulating spacecraft materials subjected to space radiations. For a variety of such samples, Conductivity values differ by up to 10(4) from values based on ASTM standards. Conductivity and charge storage properties are found to be functions of prior radiation history. A highly-charged insulator emits electrons for hours (Matter Effect) after the irradiation beam is turned off. Visible light can be used to induce emission from previously charged samples with shallow traps. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Frederickson, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Dennison, JR/0000-0002-5504-3353 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 0-7803-7910-1 PY 2003 BP 24 EP 27 DI 10.1109/CEIDP.2003.1254785 PG 4 WC Engineering, Electrical & Electronic; Physics, Condensed Matter SC Engineering; Physics GA BX92E UT WOS:000186828000004 ER PT S AU Sledd, A Danford, M Key, B AF Sledd, A Danford, M Key, B GP IEEE IEEE TI EXPRESS rack: The extension of international space station resources for multi-discipline subrack payloads SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The EXpedite the PRocessing of Experiments to Space Station or(1) EXPRESS Rack System was developed to provide Space Station accommodations for subrack payloads. The EXPRESS Rack accepts Space Shuttle middeck locker type payloads and International Subrack Interface Standard (ISIS) Drawer payloads, allowing previously flown payloads an opportunity to transition to the International Space Station (ISS). The EXPRESS Rack provides power, data command and control, video, water cooling, air cooling, vacuum exhaust, and Nitrogen supply to payloads. The EXPRESS Rack system also includes transportation racks to transport payloads to and from the Space Station, Suitcase Simulators to allow a payload developer to verify data interfaces at the development site, Functional Checkout Units to allow payload checkout at Kennedy Space Center (KSC) prior to launch, and trainer racks for the astronauts to learn how to operate the EXPRESS Racks prior to flight. Standard hardware and software interfaces provided by the EXPRESS Rack simplify the integration processes, and facilitate simpler ISS payload development. Whereas most ISS Payload facilities are designed to accommodate one specific type of science, the EXPRESS Rack is designed to accommodate multi-discipline research within the same rack allowing for the independent operation of each subrack payload. On-orbit operations began with the EXPRESS Rack Project on April 24, 2001, with one rack operating continuously to support long-running payloads. The other on-orbit EXPRESS Racks operate based on payload need and resource availability. Sustaining Engineering and Logistics and Maintenance functions are in place to maintain operations and to provide software upgrades. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Sledd, A (reprint author), NASA, George C Marshall Space Flight Ctr, FD31, Huntsville, AL 35812 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 27 EP 35 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700008 ER PT S AU Pettigrew, PJ AF Pettigrew, PJ GP IEEE IEEE TI Design features and capabilities of the first materials science research rack (MSRR-1) SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The First Materials Science Research Rack (MSRR-1) aboard the International Space Station (ISS) will offer many unique capabilities and design features to facilitate a wide range of materials science investigations. The initial configuration of MSRR-1 will accommodate two independent Experiment Modules (EMs) and provide the capability for simultaneous on-orbit processing. The facility will provide the common subsystems and interfaces required for the operation of experiment hardware and accommodate telescience capabilities. MSRR-1 will utilize an International Standard Payload Rack (ISPR) equipped with an Active Rack Isolation System (ARIS) for vibration isolation of the facility. C1 NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Dept, Biol & Phys Space Res Lab, Huntsville, AL 35812 USA. RP Pettigrew, PJ (reprint author), NASA, George C Marshall Space Flight Ctr, Micrograv Sci & Applicat Dept, Biol & Phys Space Res Lab, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 55 EP 63 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700010 ER PT S AU Carswell, W Kroeger, F Hammond, M AF Carswell, W Kroeger, F Hammond, M GP IEEE IEEE TI QMI: A furnace for metals and alloys processing on the international space station SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Quench Module Insert (QMI) is being designed for materials science research on the International Space Station (ISS). It will operate inside the Materials Science Laboratory (MSL) in the first Materials Science Research Rack (MSRR-1) as part of the Materials Science Research Facility (MSRF). This unique materials processing furnace has been designed to create an extremely high temperature gradient for the directional solidification processing of metals and alloys, but at the same time is flexible enough to process samples in either low-gradient or isothermal environments. It is also capable of quenching samples at the end of processing to freeze in the interfacial microstructure developed during processing, which can then be analyzed on the ground by the principal investigators. Design and development of QMI was challenging given the requirement to operate for a long life on the space station, where opportunities for maintenance are minimal. Development was also constrained by the small MSL processing chamber inside which the furnace will operate. Details of the performance capabilities and how they relate to enabling science, along with some of the more significant design features implemented to overcome the space station design challenge, are presented. C1 NASA, George C Marshall Space Flight Ctr, Mat Sci Team, Huntsville, AL 35812 USA. RP Carswell, W (reprint author), NASA, George C Marshall Space Flight Ctr, Mat Sci Team, SK46-UAH, Huntsville, AL 35812 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 65 EP 74 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700011 ER PT S AU Uri, JJ Cooley, V AF Uri, JJ Cooley, V GP IEEE IEEE TI International Space Station - A unique place for research SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Since March 2001, International Space Station has supported continuous research operations. The facility actually opened for the business of science in September 2000, when the first experiments were launched to the outpost, even prior to the start of a permanent human presence. Since that time, even as construction of ISS has continued, several dozen unique investigations have been completed or are still in progress. Most of the experiments are stored and operated in research racks inside the US Laboratory module Destiny. These investigations in a variety of research disciplines take advantage of at least two unique aspects of ISS: a long-duration platform to study effects of microgravity, and a vantage point in low-Earth orbit for observations of our home planet and the Universe. Experiments conducted to date have: studied the effects of long-duration microgravity on biological systems, including plants and the crewmembers themselves; taken advantage of long-duration microgravity to determine whether the production of various substances can be improved in space for basic science as well as possible commercial endeavors; studied various physical and chemical processes in microgravity; studied the internal and external environment of the space station; observed short- and long-term changes on Earth; and sought to educate and inspire students of various age groups. To date, the construction of ISS and the research conducted aboard have been remarkably successful. Future years will see an expansion of the facility as International Partners add their own research modules.(1) C1 NASA, Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. RP Uri, JJ (reprint author), NASA, Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. NR 2 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 91 EP 100 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700014 ER PT S AU Tien, JY Purcell, GH Amaro, LR Young, LE Aung, M Srinivasan, JM Archer, ED Vozoff, AM Chong, Y AF Tien, JY Purcell, GH Amaro, LR Young, LE Aung, M Srinivasan, JM Archer, ED Vozoff, AM Chong, Y GP IEEE IEEE TI Technology validation of the autonomous formation flying sensor for precision formation flying SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A Radio Frequency (RF) based sensor, called the Autonomous Formation Flying (AFF) sensor(2), has been developed to enable deep space precision formation flying by measuring the relative range and bearing angles between multiple spacecraft. The AFF sensor operates at Ka-band and uses signal-processing schemes inherited from the Global Positioning System (GPS). The key features of the AFF sensor are: (a) it operates autonomously without the aid of spacecraft or ground control, (b) it simultaneously provides a wide field of view and accurate range and bearing angle measurements and it provides accuracy better than 2 cm and 1 arcmin (1-sigma) near the bore-sight of the antenna, and (c) it provides telemetry among the constellation elements. In this paper we describe the key technology challenges, the approach to resolving them through analysis and testbed activities, and the results of the testbed activities. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tien, JY (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 129 EP 140 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700018 ER PT S AU Everett, DF Bidwell, SW Flaming, GM Rykowski, TB Stocker, EF Braatz, LE AF Everett, DF Bidwell, SW Flaming, GM Rykowski, TB Stocker, EF Braatz, LE GP IEEE IEEE TI Engineering of the Global Precipitation Measurement system SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Global Precipitation Measurement (GPM) is an international effort to improve climate, weather, and hydrological predictions through more accurate and more frequent precipitation measurements. GPM will be conducted through an international partnership led by the National Aeronautics and Space Administration (NASA) of the United States and the National Space Development Agency (NASDA) of Japan, with other organizations and countries providing additional data streams and scientific analysis. Measurements will be made with a constellation of Earth observing satellites and a global ground validation program. NASA will provide two spacecraft to the constellation, the Core and the Constellation spacecraft. For instrumentation, NASA will provide a conical-scanning, polarization-sensitive, multi-frequency microwave radiometer termed the GPM Microwave Imager (GMI) for both the Core and Constellation satellite. NASA will also provide the mission operations for the two spacecraft, two ground validation "Supersites," and the Precipitation Processing System (PPS) needed to assimilate all of the various data streams and produce the products. NASDA will provide the Dual-frequency Precipitation Radar (DPR) for the Core spacecraft, the launch of the Core spacecraft, and a data stream from the GCOM-B1 spacecraft. This paper presents the engineering of the NASA portion of GPM from scientific objectives to viable system design. GPM's six elements, (1) the flight instruments, (2) the Core spacecraft, (3) the Constellation spacecraft, (4) the mission operations system, (5) the ground validation system, and (6) the PPS, must operate together and within the political environment of partnerships in order to achieve the science objectives. Decisions on topics such as autonomy, Internet Protocol, Virtual Direct Broadcast, and orbits affect multiple elements across the mission. Advances in system engineering tools and techniques will enable a more cost-effective development effort. As GPM approaches its Preliminary Design Review (PDR) and the start of implementation, we take a look at the current system design, how we arrived here, and where we plan to go. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Everett, DF (reprint author), NASA, Goddard Space Flight Ctr, Code 420-2, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 141 EP 153 PG 13 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700019 ER PT S AU Gervin, JC McClain, CR Hall, FG Caruso, PS AF Gervin, JC McClain, CR Hall, FG Caruso, PS GP IEEE IEEE TI A comprehensive plan for studying the carbon cycle from space SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB During 2001, a team of scientists and engineers from NASA Goddard Space Flight Center (GSFC) led a planning activity for future studies of the sources, sinks, and transport of carbon in the atmosphere, on land, and in the oceans. This study was conducted at the request of NASA Headquarters. Members of the Earth sciences community and representatives from other NASA centers and Headquarters participated in a series of workshops to further refine the science questions, determine the required measurements, and identify gaps in our current measurement suite. Three critical gaps were identified: (1) Global time series of CO, atmosphere-surface exchange, (2) Ecosystem carbon storage due to land biomass and its change as well as the carbon consequences of disturbance and (3) Measurements of critical biochemicals mediating global ocean surface layer uptake and export of carbon. The observations required to fill these gaps were also defined and include: (1) Satellite-based observations of column and profile carbon dioxide concentration, (2) Reprocessing of the historic land satellite record to track land use changes over time and quantify their carbon consequences, (3) Satellite-based measurement of low density and high density biomass, and (4) Satellite measurement of chlorophyll and related organic and inorganic compounds in the coastal and upper deep ocean. The status of observation technology to support these new measurements was investigated through detailed science and engineering studies, and developed into nominal missions in the Goddard Integrated Mission Design Center. Technologies are currently not at a high enough technology readiness level to support all of these missions. A program of technology development with priorities was recommended. Algorithm development, historical data analysis, in situ and aircraft measurements, field campaigns, calibration and validation requirements, numerical model and data assimilation development, and data synthesis were also included in the recommendations. The various elements were costed, prioritized, and provided to NASA Headquarters for consideration. This material was presented to OMB and subsequent activities have benefited from this planning effort. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gervin, JC (reprint author), NASA, Goddard Space Flight Ctr, Code 420-2, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 155 EP 172 PG 18 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700020 ER PT S AU Johnston, MD Graf, JE Zurek, RW Eisen, HJ Jai, B AF Johnston, MD Graf, JE Zurek, RW Eisen, HJ Jai, B GP IEEE IEEE TI The Mars Reconnaissance Orbiter mission SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Mars Reconnaissance Orbiter (MRO) will be launched in August 2005 by an Atlas IIIB expendable launch vehicle from Cape Canaveral Air Force Station, USA. It will deliver to Mars orbit a payload to conduct remote sensing science observations, identify and characterize sites for future landers, and provide critical telecom/navigation relay capability for follow-on missions. The mission is designed to provide global, regional survey, and targeted observations from a low 255km by 320km Mars orbit with a 3:00 P.M. local mean solar time (ascending node). During the one Martian year (687 Earth days) primary science phase, the orbiter will acquire visual and near-infrared high-resolution images of the planet's surface, monitor atmospheric weather and climate, and search the upper crust for evidence of water. After this science phase is completed, the orbiter will provide telecommunications support for spacecraft launched to Mars in the 2007 and 2009 opportunities. The primary mission ends on December 31, 2010, approximately 5.5 years after launch. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, MD (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 191 EP 204 PG 14 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700022 ER PT S AU Curtis, SA Rilee, ML Truszkowski, W Clark, PE AF Curtis, SA Rilee, ML Truszkowski, W Clark, PE GP IEEE IEEE TI ANTS for the human exploration and development of space SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The proposed Autonomous Nano-Technology Swarm (ANTS) is an enabling architecture for human/robotic missions envisaged by NASA's mission for the Human Exploration and Development of Space (REDS). ANTS design principles draw on successes observed in the realm of social insect colonies, which include task specialization and sociality. ANTS spacecraft act as independent, autonomous agents for specific functions, while cooperating to achieve mission goals. For example, the Prospecting ANTS Mission (PAM) is a long-term mission concept for the 2020-2025 time frame involving individual spacecraft agents that are optimized for specific asteroid prospecting functions. The objective of PAM is to characterize at least one thousand asteroids during each year of operations in the Main Belt. To achieve this objective, PAM spacecraft, individually and as a group, must achieve a high level of autonomy. This high degree of autonomy opens the possibility of a new kind of interaction between humans and these spacecraft, where human explorers and developers could interact with ANTS enabled resources by communicating high-level goals and data products. Thus ANTS enables new kinds of missions in which both human and robotic agents work together to achieve mission goals. In this paper we review and discuss the ANTS Architecture in the context of the BEDS mission. C1 NASA, Goddard Space Flight Ctr, Planetary Magnetospheres Branch, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Curtis, SA (reprint author), NASA, Goddard Space Flight Ctr, Planetary Magnetospheres Branch, Extraterr Phys Lab, Code 695, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 255 EP 261 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700027 ER PT S AU Chouinard, CM Fisher, F Gaines, DM Estlin, TA Schaffer, SR AF Chouinard, CM Fisher, F Gaines, DM Estlin, TA Schaffer, SR GP IEEE IEEE TI An approach to autonomous operations for remote mobile robotic exploration SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper presents arguments for a balanced approach to modeling and reasoning in an autonomous robotic system. The framework discussed uses both declarative and procedural modeling to define the domain, rules, and constraints of the system and also balances the use of deliberative and reactive reasoning during execution. This paper also details the implementations of such an approach on two research rovers and a simulated rover all in a Mars-like environment. Intelligent decision-making capabilities are shown in the context of several unforeseen events, which require action. These events test the system's framework by requiring the system to handle uncertainty in state and resource estimations and in real-world execution. Future work, which further enhances the idea of balanced reasoning, is also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chouinard, CM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 313 EP 322 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700032 ER PT S AU Starbird, T Lin, I Ko, AY AF Starbird, T Lin, I Ko, AY GP IEEE IEEE TI Mission interactive scenario studio (MISS) for autonomous spacecraft SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB We propose building a Studio enabling the use of diverse existing mission activity and scenario patterns, the creation of new ones, and the modeling of their effects using existing modeling tools. The core of the Studio is a component-based Type Library, which captures years of mission adaptation patterns in various forms. The Studio works as a content server to capture the developed adaptation knowledge for reuse and provides bridging into different mission uplink implementations, including the Mission Data System [1] (MDS) state/goal machinery. Various activities can be coordinated, controlled, and reused through the Studio's component interface to establish and model a mission scenario. A special component Factory mechanism will be in place to facilitate the adaptation of projects into the Studio. The architecture of the Studio reflects and enforces a division of knowledge and actions into three parts: Model, View, Controller, (MVC). The Model contains information about (a proposed version of) the spacecraft and mission. The Controller contains logic for constructing scenarios of mission activities. The information in the Model and Controller is principally in the form of reusable patterns. A Viewer can be a simple or complex software system. For example, Activity Plan Generator (Apgen) [2,3] is one possible viewer: MDS is another. A 3-tiered infrastructure is used for the Studio, reflecting the Model, Controller, Viewer architecture [4,5]. The Studio is useful in pre-phase A of a project by enabling spacecraft design options to be played against desired mission scenarios. In later design phases of a project, the construction and modeling of more detailed scenarios is supported by the Studio. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Starbird, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-250D, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 323 EP 332 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700033 ER PT S AU Dorais, GA Gawdiak, Y AF Dorais, GA Gawdiak, Y GP IEEE IEEE TI The personal satellite assistant: An internal spacecraft autonomous mobile monitor SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper presents an overview of the research and development effort at the NASA Ames Research Center to create an internal spacecraft autonomous mobile monitor capable of performing infra-vehicular sensing activities by autonomously navigating onboard the International Space Station. We describe the capabilities, mission roles, rationale, high-level functional requirements, and design challenges for an autonomous mobile monitor. The rapid prototyping design methodology used, in which five prototypes of increasing fidelity are designed, is described as well as the status of these prototypes, of which two are operational and being tested, and one is actively being designed. The physical test facilities used to perform ground testing are briefly described, including a micro-gravity test facility that permits a prototype to propel itself in 3 dimensions with 6 degrees-of-freedom as if it were in an micro-gravity environment. We also describe an overview of the autonomy framework and its components including the software simulators used in the development process. Sample mission test scenarios are also described. The paper concludes with a discussion of future and related work followed by the summary. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Dorais, GA (reprint author), NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. 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 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 333 EP 348 PG 16 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700034 ER PT S AU Kornfeld, RP Bunker, RL Cucullu, GC Essmiller, JC Hadaegh, FY Liebe, CC Padgett, CW Wong, EC Seereeram, S Mehra, RK AF Kornfeld, RP Bunker, RL Cucullu, GC Essmiller, JC Hadaegh, FY Liebe, CC Padgett, CW Wong, EC Seereeram, S Mehra, RK GP IEEE IEEE TI New millennium ST6 autonomous rendezvous experiment (ARX) SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This Paper presents an overview of the New Millennium Space Technology 6 (ST6) Autonomous Rendezvous Experiment (ARX) mission and system. ARX is to be hosted as a payload on a United States Air Force research spacecraft. Launch is currently planned for the fall of 2004. The objective of the ARX experiment is to demonstrate and characterize an autonomous rendezvous system that autonomously locates and rendezvous with a passive object. For this experiment, the object is a sphere of approximately 20 cm diameter and simulates the current concept of the Mars Sample Return mission's Orbiting Sample (OS) Canister. The spacecraft will carry the OS into orbit, and deploy it at the start of the experiment. The Rendezvous System is centered around a light-weight, low-power scanning Laser Mapper (LAMP) sensor, providing high accuracy angle and range information, and a set of rendezvous guidance, navigation and control algorithms that autonomously guide the spacecraft to the desired state with respect to the OS. The experiment will execute a host of different proximity operations around the OS, including a number of different transfer maneuvers, approach profiles and fly-arounds of the OS. The demonstrated rendezvous technology is applicable to all future planetary sample return missions, including the Mars Sample Return mission planned for the next decade. The operational experience gained from this experiment will benefit the design of future autonomous rendezvous and sample capture missions and systems where little or no 'ground-in-the-loop' control may be possible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kornfeld, RP (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 369 EP 380 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700037 ER PT S AU Sherwood, R Chien, S Castano, R Rabideau, G AF Sherwood, R Chien, S Castano, R Rabideau, G GP IEEE IEEE TI The Autonomous Sciencecraft Experiment SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Autonomous Sciencecraft Experiment (ASE) will fly onboard the Air Force TechSat 21 constellation of three spacecraft scheduled for launch in 2006. ASE uses onboard continuous planning, robust task and goal-based execution, model-based mode identification and reconfiguration, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. In this paper we discuss how these AI technologies are synergistically integrated in a hybrid multi-layer control architecture to enable a virtual spacecraft science agent. Demonstration of these capabilities in a flight environment will open up tremendous new opportunities in planetary science, space physics, and earth science that would be unreachable without this technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sherwood, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 381 EP 390 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700038 ER PT S AU Mackey, R Some, R Aljabri, A AF Mackey, R Some, R Aljabri, A GP IEEE IEEE TI Readiness levels for spacecraft information technologies SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The New Millennium Program (NMP) seeks to advance space exploration through the maturation of promising spaceflight technologies. NMP, like many other organizations, relies upon Technology Readiness Levels (TRLs) as a key indication of technology advancement, and assesses development progress against this generalized metric. A given technology's TRL is based upon our ability to predict how the technology will perform in various applications, and therefore depends on the environment in which the technology has been tested and validated. Testing begins in the laboratory, advancing through ever-improving simulations and testbeds, until finally actual in-space validation is achieved. This process is well understood for space hardware and has been applied for many years. Presented in this paper is a modified interpretation of the traditional TRLs [1] aimed solely at information technologies. The intent of this new set of definitions is twofold: First, to enable a definitive measurement of progress among developing information technologies for spacecraft; and second, to clarify particular challenges and requirements that must be met as these technologies are validated in increasingly realistic environments. The first goal of this paper reflects NMP's need to verify clear and defensible progress of technology development on the path to spaceflight. The second goal serves to answer the question of what technologies require validation in space, and what salient features of the space environment are important to technology developers. To answer this second question, we will revisit the notion of the "relevant environment," an environment that adequately stresses the technology to provide sufficient confidence in the results. This paper includes a direct comparison between the traditional TRLs and the modified definitions specific to information technologies. We will also discuss two representative examples to illustrate this process. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mackey, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 391 EP 398 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700039 ER PT S AU Minning, CP Moynihan, PI Stocky, JF AF Minning, CP Moynihan, PI Stocky, JF GP IEEE IEEE TI Technology readiness levels for the New Millennium Program SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB National Aeronautic and Space Administration's (NASA) New Millennium Program (NMP) seeks to advance space exploration by providing an in-space validating mechanism to verify the maturity of promising advanced technologies that cannot be adequately validated with Earth-based testing alone. In meeting this objective, NMP uses NASA Technology Readiness Levels (TRL) as key indicators of technology advancement and assesses development progress against this generalized metric. By providing an opportunity for in-space validation, NMP can mature a suitable advanced technology from TRL 4 (component and/or breadboard validation in laboratory environment) to a TRL 7 (system prototype demonstrated in an Earth-based space environment). Spaceflight technology comprises a myriad of categories, types, and functions, and as each individual technology emerges, a consistent interpretation of its specific state of technological advancement relative to other technologies is problematic. The resulting ambiguity forms an inconsistent basis on which to judge a new technology's TRL. To qualify for consideration by NMP, the technology must have at least achieved TRL 3 (analytical and experimental critical function and/or characteristic proof-of-concept achieved in a laboratory environment). The TRLs used by NMP are the same as those in general use at NASA. The criteria used by NMP to determine when a given TRL is reached are added to their description and are described here. The specific criteria for exit gates have become better defined as NMP itself has evolved. A brief summary of the NMP history shows how NMP missions have evolved, thus making the consistent interpretation of TRLs increasingly important. The notion of the "relevant environment" is specifically emphasized, wherein relevant environment refers to the environment that adequately stresses the technology in order to provide sufficient confi-dence in its testing. The TRL of a given technology is based on the environment in which the technology has been tested and validated-beginning in the laboratory, advancing through ever-improving simulation and testing, until finally achieving actual in-space validation. A corollary to what qualifies as a specific technology readiness is the pervasive confusion that exists between what is actually new technology and what is development, which this paper hopes to clarify. An assigned TRL pertains to the status of the technology itself, not to a particular stage in the design and fabrication of a specific item. If new physics elements are being applied or if combined effects from conventional elements create a new function never before experienced, then an item is new technology and the TRL may be very low. However, if the components and subsystems being designed are based on known quantities, and the end product will function within experienced operating ranges that demonstrate effects similar to those of components already flown, then this process is development and the TRL would be fairly high-regardless of the difficulty of producing the product. This is the interpretation of the TRLs that the present NMP flight-validation selections are following. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Minning, CP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 1 U2 7 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 417 EP 426 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700041 ER PT S AU Sherman, B Cuviello, M Giffin, G AF Sherman, B Cuviello, M Giffin, G GP IEEE IEEE TI NASA's LWS/SET technology experiment carrier SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper examines the approach taken to building a low-cost, modular spacecraft bus that can be used to support a variety of technology experiments in different space environments. It describes the techniques used and design drivers considered to ensure experiment independence from as yet unselected host spacecraft. It describes the technology experiment carriers that will support NASA's Living With a Star Space Environment Testbed space missions. NASA has initiated the Living With a Star (LWS) Program to develop a better scientific understanding to address the aspects of the connected Sun-Earth system that affect life and society. The Space Environment Testbed (SET) Project is one element of LWS. The Project will enable future science, operational, and commercial objectives in space and atmospheric environments by improving engineering approaches to the accommodation and/or mitigation of the effects of solar variability on technological systems. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sherman, B (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 427 EP 435 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700042 ER PT S AU Rosen, PA Davis, ME AF Rosen, PA Davis, ME GP IEEE IEEE TI A joint space-borne radar technology demonstration mission for NASA and the air force SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA and the Air Force are currently studying joint technology demonstration concepts for large aperture Space Based Radar (SBR) systems. The mission focuses on elements of NASA's Earth Science Enterprise Strategic Plan and Air Force Long Term Needs for global airborne and ground moving target indication (GMTI and AMTI) surveillance, and represents an unprecedented multi-agency approach to scientific and technological advancement of spaceborne radar. The preliminary design for the system specifies a low center frequency such as L-band, a large physical aperture between 50 and 150 square meters, and on-board processing capability for synthetic aperture radar (SAR) and moving target indication applications. The key technologies requiring demonstration of technical maturity and affordability are the active electronic scanned aperture (AESA) and the real-time On-Board Processing (OBP). The system concept incorporates active metrology for measurement of the shape of the aperture, and electronics and processing capability for active compensation of the aperture surface deformation. The goal of the mission is to demonstrate the ability to maintain coherence in a very large aperture in the space environment, to show scalability to larger apertures, and to demonstrate the ability to deliver fault-tolerant real-time products in space. The system will also permit characterization of spaceborne L-band phenomenology and validate adaptive processing for moving target detection. This paper describes the trades and technology risks addressed in this study, and highlights those elements in that could be developed in concert with other SBR programs. The work is being conducted jointly by Jet Propulsion Laboratory, California Institute of Technology, and the Air Force Research Laboratory, both under contract with NASA. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rosen, PA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 437 EP 444 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700043 ER PT S AU Raphael, D Luers, P Sank, V Jackson, G AF Raphael, D Luers, P Sank, V Jackson, G GP IEEE IEEE TI Timekeeping for the space technology 5 (ST-5) mission SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Space Technology 5, or better known as ST-5, is a space technology development mission in the New Millennium Program (NMP) and NASA's first experiment in the design of miniaturized satellite constellations. The mission will design, integrate and launch multiple spacecraft into an orbit high above the Earth's protective magnetic field known as the magnetosphere. Each spacecraft incorporates innovative technology and constellation concepts which will be instrumental in future space science missions. A total of three ST-5 spacecraft will be launched as "secondary" payloads into a highly elliptical geo-synchronous transfer orbit, and will operate as a 3-element constellation for a minimum duration of 90 days. In order to correlate the time of science measurements with orbit position relative to the Earth, orbit position in space (with respect to other objects in space) and/or with events measured on Earth or other spacecraft, accurate knowledge of spacecraft and ground time is needed. Ground time as used in the USA (known as Universal Time Coordinated or UTC) is maintained by the U.S. Naval Observatory. Spacecraft time is maintained onboard within the Command and Data Handling (C&DH) system. The science requirements for ST-5 are that spacecraft time and ground time be correlatable to each other, with some degree of accuracy. Accurate knowledge of UTC time on a spacecraft is required so that science measurements can be correlated with orbit position relative to the Earth, orbit position in space and with events measured on Earth or other spacecraft. The most crucial parameter is not the clock oscillator frequency, but more importantly, how the clock oscillator frequency varies with time or temperature (clock oscillator drift). Even with an incorrect clock oscillator frequency, if there were no drift, the frequency could be assessed by comparing the spacecraft clock to a ground clock during a few correlation events. Once the frequency is accurately known, it is easy enough to make a regular adjustment to the spacecraft clock or to calculate the correct ground time for a given spacecraft clock time. The oscillator frequency, however, is temperature dependent, drifts with age and is affected by radiation; hence, repeated correlation measurements are required. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Raphael, D (reprint author), NASA, Goddard Space Flight Ctr, Code 561, Greenbelt, MD 20771 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 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 457 EP 466 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700046 ER PT S AU Buehler, MG Kuhlman, GM Keymeulen, D Myung, NV Kounaves, SP AF Buehler, MG Kuhlman, GM Keymeulen, D Myung, NV Kounaves, SP GP IEEE IEEE TI Planar REDOX and conductivity sensors for ISS water quality measurements SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Bare-metal based REDOX and conductivity sensors that are used to detect ionic species in solution by measuring the electrochemical cell current as the voltage is scanned. The simplicity and robustness of these sensors allows their use in the analysis of ionic species found in natural and drinking water. The measurements include 1) conductivity measurements which provide a gross indication of the ion concentrations present in solution, 2) Cyclic Voltammetry (CV) which provide a survey of electroactive species, and 3) Anodic Stripping Voltammetry (ASV) which allow ion identification and quantification. The ions detected are Zn, Fe, Pb, Cu, and Ag and the methodology for their extraction is discussed. Also discussed is the dependence of ASV results on the deposition time and voltage scan rate. This paper also describes the construction of the sensors, the potentiostat electronics, the measurement methodology, and applications to water quality measurements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Buehler, MG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 12 TC 1 Z9 1 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 535 EP 550 PG 16 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700051 ER PT S AU Kloepfer, JA Ponce, A Nadeau, JL AF Kloepfer, JA Ponce, A Nadeau, JL GP IEEE IEEE TI Fluorescent labels for in situ wet chemistry instruments SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID TERBIUM DIPICOLINATE PHOTOLUMINESCENCE; BACTERIAL ENDOSPORE DETECTION; CDSE NANOPARTICLES; SPORE DETECTION; QUANTUM DOTS; 25-MILLION-YEAR-OLD; DEVICES; LIFE AB Extinct or extant life on Mars would leave a variety of complex organic signatures arising from cell structures and metabolic processes. Many of these biosignatures are likely to be similar to those found on Earth. Commercially available fluorescent dyes are able to label a variety of biological molecules, although they stiffer from many drawbacks in space applications, such as sensitivity to radiation, freeze-thaw, and oxidizing environments. We evaluate a wide selection of dyes and suggest a panel that would be the most likely to succeed in a simple flight instrument with a single excitation laser. We also investigate fluorescent semiconductor quantum dots as additions to or replacements for these organic dyes. While their properties remain to be fully investigated, they show great promise for labeling of specific bacteria and metabolic processes. Finally, we report a novel endospore viability assay based on dipicolinic acid triggered terbium luminescence. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kloepfer, JA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 183-301, Pasadena, CA 91109 USA. NR 28 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 551 EP 559 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700052 ER PT S AU Wilcox, JZ Urgiles, E Douglas, S George, T Feldman, JE AF Wilcox, JZ Urgiles, E Douglas, S George, T Feldman, JE GP IEEE IEEE TI Electron-induced luminescence and X-ray spectrometer development: Progress report SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The progress in the development of a surface analysis tool based on the excitation of characteristic luminescence and x-ray spectra at ambient pressure with an electron beam is described. This instrument relies on the use of a thin electron transmissive membrane to isolate the vacuum of the electron source from the ambient atmosphere, resulting in rapid spectrum acquisition, non-destructive evaluation of surfaces, and moderate-to-high variable spatial resolution in comparison to similar portable instruments. The applications of the instrument for NASA planetary exploration include determination of surface elemental composition and identification of signatures of extinct life through correlation of x-ray and optical luminescence data. The proof-of-principle for the instrument is being demonstrated through 1) simulation of observational capabilities through electron-induced excitation of x-ray and luminescent spectra from samples of interest to geologists and exobiologists, 2) characterization of the effect of thin membranes on the properties of the excitation beam, and 3) assembly and characterization of an encapsulated prototype instrument. The x-ray and luminescence spectra are acquired and analyzed using the Environmental Scanning Electron Microscope (ESEM) and Cathodo-Luminescence (CL) spectrometer, respectively. The effect of the membrane on the electron beam is being analyzed in an SEM, and the results are correlated with the results of simulations carried out to determine performance limits and to understand the influence of membrane and atmosphere interactions on the excited spectra. X-ray spectra from metal and mineral samples were obtained without and with the membrane intersecting the electron beam. A breadboard instrument supported by a vacuum apparatus is being assembled in our laboratory. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilcox, JZ (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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 569 EP 579 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700054 ER PT S AU Trombka, JI McCoy, TJ Starr, RD Schweitzer, J Eisen, Y Evans, LG Hoover, R Floyd, S Lim, L Groves, J James, RB AF Trombka, JI McCoy, TJ Starr, RD Schweitzer, J Eisen, Y Evans, LG Hoover, R Floyd, S Lim, L Groves, J James, RB GP IEEE IEEE TI The use of neutron/gamma-ray techniques for astrobiological and geochemical exploration of planetary bodies SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID ELEMENTAL COMPOSITION; MARS ODYSSEY; SPECTROMETER; DETECTORS; HYDROGEN; SURFACE; MAPS AB Orbital and in situ measurements of characteristic gamma-ray and neutron emission spectra are used in geochemical explorations of condensed bodies in our solar system. Orbital studies measure the characteristic gamma-ray emissions produced by the natural radioactive elements K, Th, and U, and the secondary. cosmic-ray induced gamma-ray and neutron emissions. The Moon, Mars, Eros, and Phobos have been studied successfully using orbital gamma-ray and neutron spectrometers. A neutron/gamma-ray system to identify samples of geochemical or astrobiological interest for further in situ analysis or potential sample return is of great interest. This instrument could determine the presence of sub-surface water (permafrost) and pinpoint areas of biological interest. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Trombka, JI (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI Lim, Lucy/C-9557-2012 OI Lim, Lucy/0000-0002-9696-9654 NR 17 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 581 EP 595 PG 15 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700055 ER PT S AU White, C Day, S AF White, C Day, S GP IEEE IEEE TI Analysis and experimentation for the aerial deployment of planetary balloons SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper presents the development of predictive computational models for the shock forces associated with aerial deployment of very thin, uninflated, polymer balloons. A set of three models has been developed - a multi-mass rigid body model to simulate the unpackaging and unfolding kinematics, a spring-mass model to predict the shock forces, and a large displacement non-linear finite element model to predict balloon internal stresses and strains. The models are validated through experimental deployment tests in large enclosed dirigible hangars. The work shows that the shock forces are initiated internal to the balloon and subsequently propagate away, that forces increase with separation velocity, and that there can be variability in the response for nominally identical deployments. Predictions for shock forces are consistently conservative. This work brings much insight and understanding, and predictive ability to aerial deployment, but more work is needed to confidently predict design margins. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP White, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 157-316, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 625 EP 635 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700059 ER PT S AU Volpe, R AF Volpe, R GP IEEE IEEE TI Rover functional autonomy development for the Mars mobile science laboratory SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper provides an overview of the rover technology development, integration, and validation process now being used by the Mars Technology Program. Described are the relevant mission scenarios of long traverse and instrument placement, and the enabling algorithmic components that are being captured into a common software environment for demonstration and validation. As discussed, these components come from the ongoing 2003 rover mission, funded MTP research, and other complementary sources. All are providing software elements integrated into the CLARAty software system, enabling test and validation on a group of Mars rover experimental platforms. C1 CALTECH, Jet Prop Lab, Space Explorat Technol Program, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, Space Explorat Technol Program, Pasadena, CA 91125 USA. EM volpe@jpl.nasa.gov NR 27 TC 8 Z9 8 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 643 EP 652 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700061 ER PT S AU Backes, PG Norris, JS Powell, M Tso, KS Tharp, GK Leger, C AF Backes, PG Norris, JS Powell, M Tso, KS Tharp, GK Leger, C GP IEEE IEEE TI Sequence planning for the FIDO Mars rover prototype SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A planetary rover operations system has been developed and verified in terrestrial rover field tests. The Web Interface for Telescience (WITS) provides visualization of downlink data and rover command sequence generation. WITS also provides collaborative sequence generation by distributed Internet-based users. The Parallel Telemetry Processing (PTeP) system processes downlink data from the rover and places the data products in a database. The Multi-mission Encrypted Communication System (MECS) provides communication between the primary operations center and geographically distributed Internet-based users The operations system was used to visualize downlink data and generate command sequences for the Field Integrated Design and Operations (FIDO) rover in desert field tests. Complex surface operations expected of future Mars rover missions were demonstrated in the field tests. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Paul.G.Backes@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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 653 EP 670 PG 18 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700062 ER PT S AU Powell, MW Backes, PG Vona, MA Norris, JS AF Powell, MW Backes, PG Vona, MA Norris, JS GP IEEE IEEE TI Visualization of coregistered imagery for remote surface operations SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This work discusses various techniques used in visualizing sets of coregistered images for planetary lander or rover mission operations. Imagery from all available instrumentation on board a planetary rover or lander is useful in science analysis of a remote landing site. We use a visualization technique called data fusion to expedite analyzing data from an instrument suite. Data fusion uses coregistration information to overlay images from different instruments together. These overlay images are then presented to the scientist in both 2D and 3D visualization tools. Next, we introduce a technique for panorama visualization that is based on a spherical warp operation. This warping technique is optimized for computational efficiency in order to run dynamically and to support a 2D or 3D visualization tool. We then present some results of the implementation of these techniques for the 2003 MER Science Activity Planner software, using image data from the 2002 FIDO-MER field test. We conclude with a discussion of future directions for these visualization techniques. C1 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 671 EP 676 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700063 ER PT S AU Randolph, J Plescia, J Bar-Cohen, Y Bartlett, P Bickler, D Carlson, R Carr, G Fong, M Gronroos, H Guske, PJ Herring, M Javadi, H Johnson, DW Larson, T Malaviarachchi, K Sherrit, S Stride, S Trebi-Ollennu, A Warwick, R AF Randolph, J Plescia, J Bar-Cohen, Y Bartlett, P Bickler, D Carlson, R Carr, G Fong, M Gronroos, H Guske, PJ Herring, M Javadi, H Johnson, DW Larson, T Malaviarachchi, K Sherrit, S Stride, S Trebi-Ollennu, A Warwick, R GP IEEE IEEE TI Urey: To measure the absolute age of Mars SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB UREY, a proposed NASA Mars Scout mission will, for the first time, measure the absolute age of an identified igneous rock formation on Mars. By extension to relatively older and younger rock formations dated by remote sensing, these results will enable a new and better understanding of Martian geologic history. Thus, Mars will join the Earth and the Moon as the third body in the Solar System for which absolute dating has been accomplished. This revolutionary science mission can be accomplished within the Mars Scout programmatic boundaries because of both extensive heritage and innovative technology. The heritage includes the interplanetary carrier stage, the Mars direct-entry system, the Mars lander, and the Mars rover that had been planned for the Mars 2001 mission before it was cancelled. Urey innovations include two ongoing technology developments that can support a revolutionary science approach. First, miniaturizing of instruments to measure K and Ar-40 has proceeded sufficiently to allow in situ dating. Second, the ultrasonic drill, which has been under development at Jet Propulsion Laboratory for several years, can be carried on an existing small rover with design and operational heritage from the Mars Pathfinder mission. The rover's mobility is important because it can carry the drill from the landing site to a remote bedrock location where it can acquire a pristine sample by drilling into that bedrock. The rover will return the sample to the lander for analysis. These in situ analyses will produce new data about Mars chronology, geology, petrology, and chemistry that will significantly change our understanding of the history of the red planet. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Randolph, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-170U, Pasadena, CA 91109 USA. RI Plescia, Jeffrey/B-7738-2016 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 723 EP 732 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700069 ER PT S AU Nilsen, E AF Nilsen, E GP IEEE IEEE TI Europa Orbiter mission options SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB In August 2000, an independent assessment of the Europa Orbiter baseline mission was performed to evaluate the planned implementation. As part of this activity, multiple alternative mission concepts were investigated that could meet the full science objectives as well as concepts that could meet a reduced set of science objectives. The results of the study validated the estimated costs of the mission, while recommending a modified mission approach that reduced the overall risk of the mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nilsen, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 301-170U, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 733 EP 738 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700070 ER PT S AU Matousek, S AF Matousek, S GP IEEE IEEE TI Mars Scout 2007 - A current status SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Mars Program institutes the Mars Scout Missions in order to address science goals in the program not otherwise covered in baseline Mars plans. Mars Scout missions will be Principal-Investigator (PI) led science missions. Analogous to the Discovery Program, PI-led investigations optimize the use of limited resources to accomplish focused science and allow the flexibility to quickly respond to discoveries at Mars. Scout missions also require unique investments in technology and reliance upon Mars-based infrastructure such as telecom relay orbiters. Scouts utilize a two-step competitive process for selection. In Dec, 2002, the Step 2 selections by NASA were announced and then approximately five month studies will result in a selection for flight around August, 2003 for a mission to be launched in 2007. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matousek, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 264-472, 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 739 EP + PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700071 ER PT S AU Mattingly, R Matousek, S Jordan, F AF Mattingly, R Matousek, S Jordan, F GP IEEE IEEE TI Mars Sample Return, updated to a groundbreaking approach SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A Mars Sample Return (MSR) mission is a goal of the Mars Program. Recently, NASA and JPL have been studying the possibility of a Mars Sample Return some time in the next decade of Mars exploration. In 2001, JPL commissioned four industry teams to make a fresh examination of MSR architectures. Six papers on these studies were presented at last year's conference. As new fiscal realities of a cost-capped Mars Exploration Program unfolded, it was evident that these MSR concepts, which included mobility and subsurface sample acquisition, did not fit reasonably within a balanced program. Therefore, at the request of NASA and the science community, JPL asked the four industry teams plus JPL's Team X to explore ways to reduce the cost of a MSR. A NASA-created MSR Science Steering Group (SSG) established a reduced set of requirements for these new studies that built upon the previous year's work. As a result, a new "Groundbreaking" approach to MSR was established that is well understood based on the studies and independent cost assessments by Aerospace Corporation and SAIC. The Groundbreaking approach appears to be what a contemporary, balanced Mars Exploration Program can afford, has turned out to be justifiable by the MSR Science Steering Group, and has been endorsed by the Mars science community at large. This paper gives a brief overview of the original 2001 study results and discusses the process leading to the new studies, the studies themselves, and the results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mattingly, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 301-485, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 745 EP 758 PG 14 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700072 ER PT S AU Johnston, GI AF Johnston, GI GP IEEE IEEE TI A classification for multiple mission observation concepts SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Terms such as "sensorwebs," "satellite trains," and "constellations" are used to describe multiple mission observation concepts. This paper categorizes these concepts based upon how they observe. The observation aspects are: (1) the spatial distribution of the observations, (2) the degree of similarity of the observations, and (3) requirement for real-time observation coordination. The author proposes a taxonomy for these concepts based on names already proposed or in common use. Similar classifications could be based upon aspects such as communication or location. The author hopes this work will help advance the discussion and development of multiple mission observation capabilities. C1 NASA, Program Planning & Dev Div, Off Earth Sci, Washington, DC 20546 USA. RP Johnston, GI (reprint author), NASA, Program Planning & Dev Div, Off Earth Sci, Headquarters,Mail Code YF, Washington, DC 20546 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 759 EP 765 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700073 ER PT S AU Cooper, LP AF Cooper, LP GP IEEE IEEE TI Assessing risk from a stakeholder perspective SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID DECISION-MAKING; JUDGMENT AB Planetary exploration missions are subject to a vast array of interpretations of "success" based on the concerns of multiple stakeholder groups. While project risk management generally focuses on issues of cost/schedule constraints or reliability issues, a broader interpretation of "risk" as it applies to stakeholders such as sponsors (e.g., NASA), the public at large, the scientific community, the home organization, and the project team itself can provide important insights into the full spectrum of risk that needs to be managed. This paper presents a stakeholder view of risk which is divided into failure, not-a-failure, success, and stunning-success zones. Using the Mars Pathfinder mission as an example, an alternative interpretation of the risks to that mission is presented from the view of key stakeholders. The implications of the stakeholder perspective to project risk management are addressed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cooper, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 767 EP 773 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700074 ER PT S AU Tralli, DM AF Tralli, DM GP IEEE IEEE TI Programmatic risk balancing SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A lifecycle risk management decision-support tool developed for NASA space systems is used to assess and visualize risks in a research and applications program. This paper presents the first demonstration and assessment of the tool for balancing programmatic risk. The case study NASA program has a principal goal of developing geospatial information products for a broad user base. Selecting optimal combinations of risk controls, such as planning activities and assessments, plus research and applications projects, performs the risk balancing. Marginal benefits are measured in terms of residual risk. Relative differences in risk impact and control effectiveness provide indications of program integration across science, technology and applications. Results are preliminary. Sensitivity analysis confirms that at formulation, prioritization and coordination with stakeholder agencies are mitigations yielding greatest marginal benefit towards requirements attainment. At implementation, establishing project performance characteristics yields the greatest marginal benefit. The framework helps strategy design, execution, integration and prioritization. C1 CALTECH, Jet Prop Lab, Strateg Syst Technol Program, Mission & Syst Architecture Sect, Pasadena, CA 91109 USA. RP Tralli, DM (reprint author), CALTECH, Jet Prop Lab, Strateg Syst Technol Program, Mission & Syst Architecture Sect, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 775 EP 784 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700075 ER PT S AU Perera, JS AF Perera, JS GP IEEE IEEE TI Risk management for the International Space Station SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB \The International Space Station (ISS) is an extremely complex system, both technically and programmatically. The Space Station is intended to satisfy a broad range of needs and uses. It will be launched in numerous launch packages and then assembled and operated in the harsh environment of space. It is being designed and manufactured by many organizations, including the prime contractor, Boeing, the NASA institutions, and international partners and their contractors. Finally, the ISS has multiple customers, (e.g., the Administration, Congress, users, public, international partners, etc.) with contrasting needs and constraints. The risk management strategy is to proactively and systematically manage risks to help ensure ISS Program success. ISS program follows integrated risk management process (both quantitative and qualitative) and is integrated into ISS project management. The process and tools are simple and seamless and permeate to the lowest levels (at a level where effective management can be realized) and follows the continuous risk management methodology. The risk process assesses continually what could go wrong (risks), determine which risks need to be managed, implement strategies to deal with those risks, and measure and monitor the effectiveness of the implemented strategies. The process integrates all facets of risk including cost, schedule and technical aspects. Support analysis risk tools like PRA are used to support programmatic decisions and assist in analyzing risks. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Perera, JS (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 785 EP 789 PG 5 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700076 ER PT S AU Ahmed, M Brill, SR Sengupta, R Bryson, J AF Ahmed, M Brill, SR Sengupta, R Bryson, J GP IEEE IEEE TI Phases of risk management for the James Webb Space Telescope SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The James Webb Space Telescope (JWST)(1 2), mission will launch a 6-meter class infrared telescope to L2 in 2010 to study the earliest stars and galaxies formed after the "Big Bang." JWST has been designated as the highest priority mission in space astronomy by the National Academy of Sciences. As the JWST Project moves from conceptual stage through the formulation, design, and development phases and into the operational phase, the risk management emphasis and philosophy will also change. During the formulation phase, the JWST Project has exercised a top-down risk mitigation philosophy which has greatly reduced mission risk by investing significantly in a number of key technologies required for the observatory, including cryogenic and deployable lightweight mirrors, precision actuators, infrared detectors and techniques for Wavefront sensing and control. As the project moves into implementation phase, we have initiated the use of a more formal, bottom-up risk management methodology. This paper discusses the: . Two phases of risk management philosophy for the JWST program . Process of developing a web-based risk database tool . Policies and procedures in use for conducting risk management across the boundaries with a number of partners (including the prime contractor, European Space Agency, Canadian Space Agency and the Space Telescope Science Institute) . Management approaches which have been devised to address communicating and managing risks across a large, diverse, and multi-level organization. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ahmed, M (reprint author), NASA, Goddard Space Flight Ctr, Code 443, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 791 EP 797 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700077 ER PT S AU Witkowski, MM AF Witkowski, MM GP IEEE IEEE TI Cassini Risk Management during mission operations and data analysis - Application & lessons learned SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Risk is defined as the combination of the likelihood of occurrence of an undesired event and the severity of the consequences should that event occur. Risk management is the organized means of risk planning, identification & assessment, decision making and tracking risks. It is a well defined, structured approach required by the National Aeronautics and Space Administration (NASA) to manage risk during the development and operation of its spacecraft flight missions. Cassini is a joint NASA/European Space Agency (ESA) Mission to Saturn. The Cassini Program began the spacecraft and mission design/development in the early nineties and implemented a risk management process during that phase of the mission, as required. While risk management was conducted on Cassini during the development phase of the program, the process did not continue when the,mission transitioned into the Mission Operations and Data Analysis (MO&DA) Phase. As a NASA required discipline, risk management was reintroduced to the program after approximately three years of successful mission operations. Following a year of workshops, training, initial risk list development and on-line risk system tailoring, Risk Management was successfully implemented on Cassini. The process has been embraced by the Program and is working well. Risk Management implementation on Cassini however, was not without its share of lessons learned. The Cassini process development presented challenges that if not aggressively addressed, could increase the risk of failure to others who try to introduce a new process during MO&DA. This paper will detail some of the key challenges faced while introducing Risk Management to the mission operations team. It is hoped that the lessons learned during the implementation of the Cassini Risk Management Process will assist others in developing a robust process for use during Mission Operations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Witkowski, MM (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 799 EP 806 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700078 ER PT S AU Cornford, SL Paulos, T Meshkat, L Feather, MS AF Cornford, SL Paulos, T Meshkat, L Feather, MS GP IEEE IEEE TI Towards more accurate life cycle risk management through integration of DDP and PRA SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Risk assessment is one of the key inputs to an informed decision making process. Risk management based on quantitative assessment of risk has been a mainstay of decision making for several decades. The term "Probabilistic Risk Assessment" (PRA) encompasses a mature and widely used set of techniques for conducting quantitative risk assessments. Originating in the nuclear power industry, they are now regularly applied in the nuclear, process, chemical, petroleum, aerospace, and other industries. PRA techniques are especially suited to assessing the risk of a complex system operating in a rich and changing environment. They are able to take into account knowledge of the system's components' reliabilities, system interdependencies, knowledge of the environment in which it operates and knowledge of the system design. The net result is an assessment and understanding of the reliability of the whole system in its operational context. This gives insight into the strengths and weaknesses of the system-for example, revealing where vulnerabilities exist (thus suggesting key areas for improvement). Information such as this can be key to informed decision making. One of the challenges for PRA techniques is application early in the life cycle, most especially in the formative stages of development, when the system design is incomplete, immature and/or still in flux. However, this is a time of key decision-making. Those early design decisions will have major consequences that pervade all the subsequent phases: development, test, deployment, operation, maintenance and, ultimately, decommissioning. NASA's Defect Detection and Prevention (DDP) process has been created to address this need for early lifecycle risk assessment and management. DDP employs a simple form of quantitative analysis that is designed for application at very early stages but evolves with the project over its life cycle. DDP currently has some detailed modeling capability, and could easily be upgraded to include more of this capability. However, it is the intent of the DDP team to leverage and integrate existing tools whenever possible and there are a number of well-established tools and techniques for performing detailed quantitative risk assessment. The focus of this paper is on the integration of PRA and DDP. The intent is twofold: to extend risk-based decision though more of the lifecycle, and to lead to improved risk modeling (hence better informed decision making) wherever it is applied, most especially in the early phases as designs begin to mature. The sections that follow: 1. Summarize the salient points of PRA and DDP. 2. Describe a case study in which separate applications of PRA and DDP on the same system were then compared. 3. Describe how the results of those separate applications can be used to bolster each other. 4. Present our vision for a true integration of PRA and DDP, which will make life-cycle risk management feasible for complex, large-scale systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 807 EP 814 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700079 ER PT S AU Esposito, TC AF Esposito, TC GP IEEE IEEE TI Multiple Autonomous Discrete Event Controllers for Constellations SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Multiple Autonomous Discrete Event Controllers for Constellations (MADECC) project is an effort within the National Aeronautics and Space Administration Goddard Space Flight Center's (NASA/GSFC) Information Systems Division to develop autonomous positioning and attitude control for constellation satellites. It will be accomplished using traditional control theory and advanced coordination algorithms developed by the Johns Hopkins University Applied Physics Laboratory (JHU/APL). This capability will be demonstrated in the discrete event control test-bed located at JHU/APL. This project will be modeled for the Leonardo(1) constellation mission, but is intended to be adaptable to any constellation mission. To develop a common software architecture, the controllers will only model very high-level responses. For instance, after determining that a maneuver must be made, the MADECC system will output a DeltaV (velocity change) value. Lower level systems must then decide which thrusters to fire and for how long to achieve that DeltaV. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Esposito, TC (reprint author), NASA, Goddard Space Flight Ctr, Code 583, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 853 EP 858 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700083 ER PT S AU Meyer, CM Fulton, C Maul, B Chicatelli, A Cannon, H Bajwa, A Balaban, E Wong, E AF Meyer, CM Fulton, C Maul, B Chicatelli, A Cannon, H Bajwa, A Balaban, E Wong, E GP IEEE IEEE TI Propulsion IVHM technology experiment overview SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA researchers recently demonstrated successful real-time fault detection and isolation of a virtual reusable launch vehicle main propulsion system. Using a detailed simulation of a vehicle propulsion system to produce synthesized sensor readings, the NASA team demonstrated that advanced diagnostic algorithms, running on flight-like computers, can, in real time, successfully diagnose the presence and cause of faults. This demonstration was conducted as part of the NASA Propulsion IVHM Technology Experiment, or PITEX. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Meyer, CM (reprint author), NASA, Glenn Res Ctr Lewis Field, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 4 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 859 EP 868 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700084 ER PT S AU Bajwa, A Sweet, A AF Bajwa, A Sweet, A GP IEEE IEEE TI The Livingstone model of a main propulsion system SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Livingstone is a discrete, propositional logic-based inference engine that has been used for diagnosis of physical systems. We present a component-based model of a Main Propulsion System (NIPS) and say how it is used with Livingstone (L2) in order to implement a diagnostic system for integrated vehicle health management (IVHM) for the Propulsion IVHM Technology Experiment (PITEX). We start by discussing the process of conceptualizing such a model. We describe graphical tools that facilitated the generation of the model. The model is composed of components (which may map onto physical components), connections between components and constraints. A component is specified by variables, with a set of discrete, qualitative values for each variable in its local nominal and failure modes. For each mode, the model specifies the component's behavior and transitions. We describe the MPS components' nominal and fault modes and associated Livingstone variables and data structures. Given this model, and observed external commands and observations from the system, Livingstone tracks the state of the NIPS over discrete time-steps by choosing trajectories that are consistent with observations. We briefly discuss how the compiled model fits into the overall PITEX architecture. Finally we summarize our modeling experience, discuss advantages and disadvantages of our approach, and suggest enhancements to the modeling process. C1 NASA, USRA, RIACS, Moffett Field, CA 94035 USA. RP Bajwa, A (reprint author), NASA, USRA, RIACS, MS 269-4, Moffett Field, CA 94035 USA. NR 7 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 869 EP 876 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700085 ER PT S AU James, ML Baroth, E Mellinger, L Park, H Stough, T Brown, SA Meyer, CM AF James, ML Baroth, E Mellinger, L Park, H Stough, T Brown, SA Meyer, CM GP IEEE IEEE TI Integrated Virtual Test Bed for IVHM systems on 2nd Generation RLV SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The IVHM Virtual Test Bed (IVTB) is a systems integration and test facility being developed by Northrop Grumman Corporation and the Jet Propulsion Laboratory, along with NASA partners Glenn Research Center and Ames Research Center. Its purpose is to support the demonstration and validation of Integrated Vehicle Health Management (IVHM) technologies for NASA's 2(nd) Generation Reusable Launch Vehicle program. The IVTB will be used to validate spacecraft health management system designs, and to infuse, evaluate, and mature new technologies. The IVTB; will be used to identify and resolve problems at the early stages of development and facilitate technology transfer. In addition, the IVTB can be used for assembling and testing ground and spacecraft elements using the distributed environment capabilities, and supporting post launch operations and mission scenario testing. As a proof-of-concept, a simulation of the X-34 RLV propulsion feed system and liquid oxygen tank structure was chosen. The experiment will use a hierarchical health management system wherein a system-level IVHM will collect and analyze the subsystem-level diagnostics to demonstrate capabilities not possible with only subsystem level information. C1 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. 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 877 EP 886 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700086 ER PT S AU Fijany, A Vatan, F Barrett, A James, M Williams, C Mackey, R AF Fijany, A Vatan, F Barrett, A James, M Williams, C Mackey, R GP IEEE IEEE TI A novel model-based diagnosis engine: Theory and applications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID COMPLEXITY; ALGORITHMS AB Over the past decade, the number of Earth orbiters and deep space probes has grown dramatically and is expected to continue in the future as miniaturization technologies drive spacecraft to become more numerous and more complex. This rate of growth has brought a new focus on autonomous and self-preserving systems that depend on fault diagnosis. Although diagnosis is needed for any autonomous system, current approaches are almost uniformly "ad-hoc," inefficient, and incomplete. Systematic methods of general diagnosis exist in literature, but they all suffer from two major drawbacks that severely limit their practical applications. First, they tend to be large and complex and hence difficult to apply. Second and more importantly, in order to find the minimal diagnosis set, i.e., the minimal set of faulty components, they rely on algorithms with exponential computational cost and hence are highly impractical for application to many systems of interest. In this paper, we propose a two-fold approach to overcome these two limitations. Then we report the details of a new and powerful tool, Diagnosis Engine version 1.0, we have developed based on these techniques. First, we propose a novel and compact reconstruction of General Diagnosis Engine (GDE), as one of the most fundamental approaches to model-based diagnosis. We then present a novel algorithmic approach for calculation of minimal diagnosis set. Using a powerful yet simple representation of the calculation of minimal diagnosis set, we map the problem onto two well-known problems, that is, the Boolean Satisfiability and 0/1 Integer Programming problems. The mapping onto Boolean Satisfiability enables the use of very efficient algorithms with a super-polynomial rather than an exponential complexity for the problem. The mapping onto 0/1 Integer Programming problem enables the use of a variety of algorithms that can efficiently solve the problem for up to several thousand components. These new algorithms significantly improve over the existing ones, enabling efficient diagnosis of large complex systems. In addition, the latter mapping allows, for the first time, determination of the bound on the solution, i.e., the minimum number of faulty components, before solving the problem. This is a powerful insight that can be exploited to develop yet more efficient algorithms for the problem. At the end, we report the results of validating and benchmarking of our engine based on this technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Amir.Fijany@jpl.nasa.gov; Farrokh.Vatan@jpl.nasa.gov; Anthony.C.Barrett@jpl.nasa.gov; Mark.James@jpl.nasa.gov; cpw@cs.stanford.edu; Ryan.M.Mackey@jpl.nasa.gov NR 17 TC 0 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 901 EP 910 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700088 ER PT S AU Jones, DL AF Jones, DL GP IEEE IEEE TI Geometric configurations for large spacecraft-tracking arrays SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A significant increase in the sensitivity of ground facilities used for spacecraft telemetry reception and navigation can be obtained through the use of large numbers of inexpensive, mass-produced parabolic antennas with diameters of a few meters. Planned arrays for the Deep Space Network (DSN) and for radio astronomy involve up to several thousand small antennas, providing collecting areas approaching a square kilometer. The geometric configuration of arrays intended for spacecraft tracking will differ from those for radio astronomical observations. This paper will explore the configuration constraints and tradeoffs for a prototype DSN array being developed at JPL. The optimum configuration for the 100-antenna prototype array is determined by tradeoffs between cost, maximum baseline length, shadowing, instantaneous sidelobe levels, and ease of atmospheric phase calibration. C1 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 997 EP 1002 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700099 ER PT S AU Jamnejad, V AF Jamnejad, V GP IEEE IEEE TI Simple gain probability functions for large reflector antennas of JPL/NASA SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Simple models for the patterns as well as their cumulative gain probability and probability density functions of the JPL/NASA Deep Space Network (DSN) antennas are developed. These are needed for the study and evaluation of interference from unwanted sources such as the emerging terrestrial system, High Density Fixed Service (HDFS), with the Ka-band receiving antenna systems in Goldstone Station of the JPL/NASA Deep Space Network. Several different models for the high gain ground antennas of the JPL/NASA Deep Space Network (DSN) are considered. The model definitions are then used to evaluate cumulative probability functions and probability density functions for the gain values at a receiving antenna randomly located anywhere in the far field of the model antenna. Both two-dimensional models which simulate the pattern in a plane cut through the boresight of the antenna and the range of the angle from boresight to +/-180 degrees and three-dimensional ones in which the pattern is given anywhere in the half-space above the ground, with the range of angle from zero at boresight to 90 degrees are considered. hi both cases, regular as well as smooth "interpolated" models have been developed. The gain value as seen by a receiver at a random location and exposed to the radiation from a transmitting antenna with a given gain profile, can be thought of as a uniformly distributed random variable. Formulas are derived and various plots are presented for the gain models and their associated cumulative probability flinctions and probability density functions. C1 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1003 EP 1014 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700100 ER PT S AU Vodonos, Y Conroy, B Cornish, T Losh, D Silva, A McDowall, G Ocampo, J Santos, T AF Vodonos, Y Conroy, B Cornish, T Losh, D Silva, A McDowall, G Ocampo, J Santos, T GP IEEE IEEE TI Development of a new 20kW CW transmitter for 34-meter antennas of NASA's Deep Space Network SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A new generation of 20kW dual-band (S/X) transmitters was developed for NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) Antennas. Innovations include additional X-band communication capability for High Earth Orbit (HEO) missions, new control algorithms, automated calibration, improved and expanded monitoring and diagnostics, reduced cabling, and improved maintainability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vodonos, Y (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1015 EP 1022 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700101 ER PT S AU Mackenzie, AI Cravey, RL Dudley, KL Fralick, DT Miner, GA Stoakley, DM AF Mackenzie, AI Cravey, RL Dudley, KL Fralick, DT Miner, GA Stoakley, DM GP IEEE IEEE TI Fabrication and electromagnetic characterization of novel self-metallized thin films SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID OPTICS AB Unique, self-metallized films were investigated for deployable reflector antenna applications at L-band. Polyamic acid resins or soluble polyimides were doped with metal complexes, cast into films, and thermally cured. Each resulting film had a metallic layer on one side, adhering unfailingly to the polymer. Metallization was successful for silver or palladium in 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA) and 4,4'-oxydianiline and for gold in BTDA and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (4-BDAF) or the space durable polyimide, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 4-BDAF (LaRC-CP1(TM)). Reflectivity, transmissivity, and emissivity were determined, using an HP 8510 Vector Network Analyzer, to within 0.001 precision and accuracy. A custom-made test fixture/positioner, a thru-reflect-line calibration, and calculated reflection coefficients were used. The Ag film proved most suitable for farther study, with 0.9957 reflectivity and 0.0042 emissivity. The Pd films were 0.89 reflective and 0.11 emissive; both An films tested entirely transmissive. Transmission and scanning electron micrographs, S-parameters, and power coefficients are shown. C1 NASA, Langley Res Ctr, Sensors Res Branch, Hampton, VA 23681 USA. RP Mackenzie, AI (reprint author), NASA, Langley Res Ctr, Sensors Res Branch, MS 473, Hampton, VA 23681 USA. NR 23 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1023 EP 1037 PG 15 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700102 ER PT S AU Fralick, DT Lichodziejewski, D Cravey, RL Hopkins, GD Bailey, MC AF Fralick, DT Lichodziejewski, D Cravey, RL Hopkins, GD Bailey, MC GP IEEE IEEE TI Performance evaluation of a membrane waveguide array antenna SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA Langley Research Center (LaRC) has pursued the development of tensioned membrane antenna technology for several years. For many applications, it is desirable to have space-based antennas which are very large. As the physical size increases, antennas constructed of conventional materials quickly become too bulky and heavy to be practical for space applications. For some of these applications, such as earth remote sensing, reducing electromagnetic losses in the antenna is also critical. For this reason, there is interest in finding new methods of fabricating large antennas which not only exhibit lighter weight than conventional antennas, but also meet stringent electromagnetic performance criteria. One configuration which has been investigated by NASA LaRC is a slotted waveguide array antenna constructed of a metallized thin membrane material. Several test articles have been built and tested to validate this configuration. This concept will lend itself to compact packaging for launch, and can be tensioned on an inflatable, rigidizable support structure, which would deploy once on orbit. One major advantage of this planar configuration is that there is no need for fabricating a doubly curved surface (such as for a reflector antenna) from membrane material. One of the most challenging technical issues to be faced in constructing antennas such as the ones described above is that of designing the antenna and feed network to minimize electromagnetic losses while maintaining compatibility with a light, thin, membrane structure. This paper describes the electromagnetic evaluation of an eight element metallized membrane L-band waveguide array antenna with an integrated membrane feed network. Though there are still some technical hurdles to overcome before this technology is applicable for earth remote sensing from space, the result of the performance evaluation shows that further investigation is warranted. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fralick, DT (reprint author), NASA, Langley Res Ctr, MS 490, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1039 EP 1044 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700103 ER PT S AU Fischman, MA Berkun, AC Cheng, FT Chun, WW Im, E Andraka, R AF Fischman, MA Berkun, AC Cheng, FT Chun, WW Im, E Andraka, R GP IEEE IEEE TI Design and demonstration of an advanced on-board processor for the second-generation precipitation radar SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Next-Generation Precipitation Radar (PR-2) prototyped by NASA/JPL will depend heavily on high-performance digital processing to collect meaningful rain echo data. Using field-programmable gate arrays (FPGAs), we have developed for the PR-2 a pulse-compression processor and adaptive timing controller that will enable full on-board processing capabilities in a 13 and 36 GHz spaceborne radar. This paper describes some of the new technologies for the on-board processor, including a 40 x 109 op/s bit-serial filter attaining -60 dB range sidelobe performance, and an adaptive scanning control and timing unit (CTU) which yields a 7-fold increase in the radar's dwell time over areas of precipitation. C1 CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, Pasadena, CA 91109 USA. RP Fischman, MA (reprint author), CALTECH, Jet Prop Lab, Radar Sci & Engn Sect, MS 300-241,4800 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1067 EP 1075 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700106 ER PT S AU Moller, D Rodriguez, E Moghadamm, M Hoffman, J AF Moller, D Rodriguez, E Moghadamm, M Hoffman, J GP IEEE IEEE TI A dual-low-frequency radar for sub-canopy and deep soil-moisture measurements SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID FOREST BIOMASS; IMAGING RADARS AB Measurements of deep and sub-canopy soil moisture are critical in understanding the global water and carbon energy cycle, but are not presently available on a synoptic basis. In this paper, we discuss a proposed spaceborne dual-frequency (UHF and VHF) radar that can provide globally these key measurements. This system is polarimetric and the low transmit frequencies chosen for their penetration abilities necessitate a large antenna that has an aperture of approximately 30m by 11m at VHF, and 30m by 3m at UHF. We describe the mission concept, overall system design and performance characteristics, and discuss ongoing tasks to prototype key system components, and verify the retrieval algorithms. We are also developing a tower-based prototype radar system. This system will, through field observations, demonstrate the scientific effectiveness of the measurement concept and provide critical data for algorithm development. We provide details of the ground experimentation including issues unique to operating at the low-firequencies chosen for these systems. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91107 USA. RP CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91107 USA. EM delwyn.moller@jpl.nasa.gov NR 20 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1103 EP 1113 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700110 ER PT S AU Pollard, BD Sadowy, G Moller, D Rodriguez, E AF Pollard, BD Sadowy, G Moller, D Rodriguez, E GP IEEE IEEE TI A millimeter-wave phased array radar for hazard detection and avoidance on planetary landers SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Safe, precise landing in difficult planetary terrain, including areas that are rocky, heavily sloped, or both, requires remote sensing of the surface in order to choose an appropriate landing site. While active or passive optical sensors might seem appropriate for this application, we are developing an alternate approach based on a millimeter-wave electrically scanned phased array radar. A radar offers several advantages over present optical sensors, including a substantial reduction in dust or engine plume susceptibility, a larger range of operating altitudes, and a coherent measurement of the platform velocity. In this paper, we describe the overall system design for a radar being developed for the NASA Mars Science Laboratory, set to launch in 2009. We discuss the terminal descent scenario, and the requirements imposed by the terminal guidance and landing vehicle hazard tolerance. We present algorithms for the measurement of digital elevation and roughness map generation from the returned waveforms, and discuss system performance of a candidate sensor as derived analytical models and point target simulations of synthetic Mars terrain. We also present a novel, fast velocity vector retrieval algorithm that avoids the necessity of inverting the entire phase matrix, making it ideal for onboard computation. Finally, we describe our present and future hardware development efforts, including the development of a system test bed that will be used in the prototype sensor. This system is capable of the required 1 GHz bandwidth and five hops in center frequency. Our future development and testing plans will use this test bed to develop a full millimeter-wave phased array, leading to a unique hazard detection sensor for this exciting mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pollard, BD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1115 EP 1122 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700111 ER PT S AU Lee, CH Cheung, KM Vilnrotter, VA AF Lee, CH Cheung, KM Vilnrotter, VA GP IEEE IEEE TI Fast Eigen-based signal combining algorithms for large antenna arrays SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A large array of small antennas can be used to enhance signals with very low signal-to-noise ratio and can also be used to replace large apertures. In this paper, a fast combining algorithm is proposed and analyzed to maximize the combined output signal-to-noise ratio. Our approach does not assume any sequence of trained symbols and is a blind combining technique, which does not require a priori knowledge of spacecraft's or the array's spatial information. Our method for computing the optimal weight is based on the generalized Eigen theory and the algorithms are built upon the Power method. Unique advantages of our proposed algorithm include (i) no formation of covariance matrices and hence less storage is required (ii) the optimal weight is obtained with significant less efforts and thus the optimal weight can be attained more quickly (iii) our proposed algorithm is capable of handling the case when the symbol signal-to-noise-ratios at the receivers are very weak. Mathematical framework for large antenna arrays using the Eigen-based signal combining techniques along with detailed performance analysis, numerical algorithms and computer simulations are presented. 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1123 EP 1129 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700112 ER PT S AU Ivancic, WD AF Ivancic, WD GP IEEE IEEE TI Architecture study of space-based satellite networks for NASA missions SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Traditional NASA missions, both near Earth and deep space, have been stove-pipe in nature and point-to-point in architecture. Recently, NASA and others have conceptualized missions that required space-based networking. The notion of networks in space is a drastic shift in thinking and requires entirely new architectures, radio systems (antennas, modems, and media access) and possibly new protocols. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ivancic, WD (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd,MS 54-5, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1179 EP 1186 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700119 ER PT S AU Smith, JF Plummer, C Plancke, P AF Smith, JF Plummer, C Plancke, P GP IEEE IEEE TI Standardization activity for Spacecraft Onboard Interfaces SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Consultative Committee for Space Data Systems (CCSDS) is an international organization of national space agencies that is organized to promote the interchange of space related information. CCSDS is branching out to provide new standards to enhanced reuse of spacecraft equipment and software onboard of a spacecraft. This effort is know as Spacecraft Onboard Interface (SOIF). SOIF expects that these standards will be well used within the space community, and that they will be based on the well-known Internet protocols. This paper will provide a description of the SOIF work by reviewing this work with three orthogonal views. The Services View describes the data communications services that are provided to the users. The Interoperability view provides a description to users on how to use SOIF to interchange between different spacecraft data busses. And finally, the Protocol view, describes the protocols and services that are to be implemented in order to provide the users with the advantages of the SOIF architecture. This paper will give the reader an excellent introduction to the work of the international SOIF team. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smith, JF (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1281 EP 1289 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700130 ER PT S AU Lamarra, N McVittie, T AF Lamarra, N McVittie, T GP IEEE IEEE TI Information architecture for a planetary "exploration web" SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The commercial Internet is evolving service-oriented capabilities to simplify and enable new kinds of distributed applications in business, engineering, and management. This "web-services" concept derives from a vision of the connected economy, in which business success in delivering customer services depends on efficient utilization of their providers' services in an increasingly inter-dependent economy. By "web services" we mean a common way of deploying distributed applications whose software components and data sources may be in different locations, formats, languages etc. Although such collaboration is not utilized significantly in planetary exploration, we believe there is significant benefit in developing an architecture in which missions could leverage each others' capabilities. We believe that incremental deployment of a service-oriented architecture could significantly contribute to the evolution of increasingly capable, efficient, and even autonomous remote exploration. The architecture supports a global vision of exploration, helping each new mission to build upon others, not merely by reusing heritage, but by planned IT infrastructure evolution. We are calling the resultant system a planetary "exploration web", in which craft like rovers, landers, and orbiters collaboratively utilize all assets more effectively. We believe this will provide increased ROI, i.e., potentially much greater science return with lower operations cost, as well as making individual missions simpler and more robust, hence lower risk. Such an architecture would simplify access to information such as navigation, weather, terrain, and remote computation, and can become progressively capable as more services are deployed and more craft collaborate. As with the web-services approach, participation can be made extremely simple (e.g., for low-cost sensor web micro-units), yet allowing resources such as bandwidth and storage can be more effectively shared (e.g., between a fixed micro-sensor, rover and orbiter). Further, this approach could assist in realizing the potential of agent-assisted exploration, whereby automated participants are producing or consuming information at various levels. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lamarra, N (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 126-201, 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1291 EP 1294 PG 4 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700131 ER PT S AU Gao, JL AF Gao, JL GP IEEE IEEE TI Optical retroreflector-based sensor networks for in-situ science applications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB In this paper we discuss the communication services requirements and constraints for future in-situ science network applications and present a peer-to-peer communication architecture using space-division optical retro-reflectors. We described how to operate the optical retro-reflectors links in both full and half-duplex modes, and analyze the energy efficiency and the trade-offs between sensor traffic, network size, link budget, duplex mode and the optical characteristics of the system. Our analysis shows full-duplex operation has the potential to double the energy efficiency achieved by traditional half-duplex operation when in-situ peer-to-peer communications becomes a dominant component in the overall network traffic. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gao, JL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1295 EP 1302 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700132 ER PT S AU Clare, LP Jennings, EH Gao, JL AF Clare, LP Jennings, EH Gao, JL GP IEEE IEEE TI Performance evaluation modeling of networked sensors SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Substantial benefits are promised by operating many spatially separated sensors collectively. Such systems are envisioned to consist of sensor nodes that are connected by a communications network. A simulation tool is being developed to evaluate the performance of networked sensor systems, incorporating such metrics as target detection probabilities, false alarms rates, and classification confusion probabilities. The tool will be used to determine configuration impacts associated with such aspects as spatial laydown, and mixture of different types of sensors (acoustic, seismic, imaging, magnetic, RF, etc.), and fusion architecture. The QualNet discrete-event simulation environment serves as the underlying basis for model development and execution. This platform is recognized for its capabilities in efficiently simulating networking among mobile entities that communicate via wireless media. We are extending QualNet's communications modeling constructs to capture the sensing aspects of multi-target sensing (analogous to multiple access communications), uni-modal multi-sensing (broadcast), and multi-modal sensing (multiple channels and correlated transmissions). Methods are also being developed for modeling the sensor signal sources (transmitters), signal propagation through the media, and sensors (receivers) that are consistent with the discrete-event paradigm needed for performance determination of sensor network systems. This work is supported under the Microsensors Technical Area of the Army Research Laboratory (ARL) Advanced Sensors Collaborative Technology Alliance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clare, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1313 EP 1322 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700134 ER PT S AU Gray, A Okino, C Jennings, EH AF Gray, A Okino, C Jennings, EH GP IEEE IEEE TI Location determination methods employing a network of passive beacons SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A mobile sensor platform that is capable of determining its precise location on the surface of Titan, one of Saturn's moons, or other extra-terrestrial area without a global positioning system (GPS) or orbiter has tremendous science value. This capability can allow the in-situ sensor platform to remain at or even return to a location of high scientific interest with great precision, as well as to determine the precise position science data is collected. We present an overview of in-situ navigation architectures utilizing various methods for performing fast, precise, in-situ location determination needed by an aerial vehicle acting as a mobile sensor platform on Titan without the use of an orbiter. Emphasis is placed on architectures that utilize potentially low-cost passive beacons. The fine resolution navigation or in-situ location determination may be used in conjunction with "course" navigation obtained via a long haul link to Earth. The "course" navigation allows the aerial vehicle to move between networks of beacons that are deployed at locations of high science interest. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gray, A (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1323 EP 1331 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700135 ER PT S AU Jennings, EH Gin, J Okino, CM AF Jennings, EH Gin, J Okino, CM GP IEEE IEEE TI Efficient information dissemination for NSOC SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB In this paper, we propose an architecture that will utilize a group of nodes (rovers) in a cooperative manner to perform efficient rover to orbiter communications. The significant contribution in this paper is an efficient method for information dissemination of data using a Node Selection Orthogonal Coding (NSOC) [1] scheme. We present bounds on the total number of transmissions sufficient for successful dissemination when preparing to use NSOC and compare results to previous bounds for well-defined topologies using information dissemination with cooperative modulation techniques [2]. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jennings, EH (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1347 EP 1356 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700138 ER PT S AU Satorius, EH Ye, Z AF Satorius, EH Ye, Z GP IEEE IEEE TI A new lock detection scheme for phase locked loops and Costas loops SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A new lock detection scheme for NASA's Mars Reconnaissance Orbiter (MRO) Project Electra payload has been proposed. Compared to the conventional lock detector of phase locked loops (PLLs) and Costas loops, this proposed scheme has better performance. It can be used to indicate lock status during acquisition as well as cycle slip during tracking mode. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Satorius, EH (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1397 EP 1404 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700143 ER PT S AU Amoozegar, F Jamnejad, V Pham, T Cesarone, R AF Amoozegar, F Jamnejad, V Pham, T Cesarone, R GP IEEE IEEE TI Trends in development of broad-band phased arrays for space applications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Occasionally, it is argued that the cost and size of the phased array antennas are prohibitive for space applications. It should be noted however, that combining the communication, imaging, and multi-target tracking capabilities of a broad-band phased array antenna has made it an attractive solution for high speed mobile ATM networks, air traffic control, collision avoidance systems, wireless local area networks (WLAN), and radar imaging. Miniature phased arrays for smart sensor probes, and robotic networks seem yet other domains of new phased array applications, which could as well be utilized for interplanetary applications. The increasing usage of the phased array antennas is playing a key role in lowering the cost and size of the T/R modules, pack-aging, cooling, and integration at an amazingly fast pace. One of the beauties of phased array antennas, which is occasionally overlooked, is its modular nature, i.e., if the first module prototype is successful, one can add more modules, with minimum down time. Reflector antennas don't have this scalable feature without much more complexity, or down time. While there are several programs, that are employing phased array antennas for earth orbits, there has not been sufficient effort in the development of phased array antennas for applications from high earth orbits to deep space vehicles and robotic networks. In this paper we will discuss and analyze various ways that phased array technology can be utilized to provide multifunction capabilities for planetary space applications. It will also be shown how phased array antennas add much flexibility to deep space applications, e.g., ground support systems. Mars networks, and monitoring high-speed robotic missions. Various beam-forming network architectures including power dividing/combining and phase-shifting techniques will be outlined and ways to reduce cost, weight and complexity of T/R modules and beam-formers will be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Amoozegar, F (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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1413 EP 1424 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700145 ER PT S AU Hurd, WJ AF Hurd, WJ GP IEEE IEEE TI Greatly enhanced deep space mission data return using very large DSN arrays SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Deep Space Network (DSN) can enable greatly enhanced mission data return from deep space missions by implementing very large arrays of relatively small antennas for signal reception. The cost per bit of science data return can be reduced by two orders of magnitude compared to today. The vision is to have arrays at each of the three DSN longitudes with aperture and performance equivalent to 100 70-m antennas, within approximately 20 years. Using Ka-band (32 GHz), this would enable data rates 400 to 500 times that achievable by current 70-m antennas using X-band (8 GHz). Data rates now achieved at typical Mars distance could be achieved at Pluto. A single mission would be able to map an entire planet, compared to the few percent of the surface mapped by today's missions. Hyper-spectral imaging and high-definition television are also enabled. The baseline system design calls for 3600 antennas, each of 12-m diameter, at each longitude. The antennas would be located at several widely separated sites at each longitude. This provides weather diversity for Ka-band reception, enabling very high system availability. Site diversity also enables the delta-differenced one-way range (delta DOR) data type, which is becoming increasingly important to deep space missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hurd, WJ (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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1425 EP 1432 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700146 ER PT S AU Gal-Edd, J Mooney, M Fatig, CC AF Gal-Edd, J Mooney, M Fatig, CC GP IEEE IEEE TI L2-James Webb Space Telescope's communication challenges SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB As technologies allow for the capture of photons in greater quantities as the number of pixels on each array increases, the amount of data to be transmitted to the ground also increases. Instruments are placed in L1 and L2 orbits, and L2 is an excellent orbit to perform observation as it is removed from earth and moon light. As space missions explore the outer reaches of the galaxy and for the universes primal origins, retrieving this vast quantity of information becomes harder from distances farther from Earth. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gal-Edd, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1433 EP 1440 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700147 ER PT S AU Kerczewski, RJ Apaza, RA AF Kerczewski, RJ Apaza, RA GP IEEE IEEE TI Requirements for air traffic management in the en-route environment SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Future aviation traffic is expected to continue to increase at 2% or more annually for the foreseeable future, unless the aviation system capacity acts to constrain this growth. To remove long-term airspace capacity limitations, new methods of air traffic management must be implemented. These new methods will necessarily require significant increases in the flow of information between air traffic management entities both on the ground and in the air. To support increased information flow, new aviation communications architectures are being investigated. One architecture gaining advocacy uses satellite communications for aircraft-ground and aircraft-aircraft communications while aircraft are flying in the en-route phase of flight. The purpose of this paper is to investigate the communications requirements for the en-route part of such an architecture. hi particular, we will derive the instantaneous aircraft volume in the en-route environment by examining current air traffic statistics, as well as projections for future traffic. We also analyze the volume of data flow that might occur between aircraft in the en-route environment and air traffic management entities on the ground and examine the implications of these results on the design of satellite communications links that would serve the en-route communications requirements in the future. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kerczewski, RJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1525 EP 1532 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700155 ER PT S AU Satorius, EH Ye, Z Ely, T AF Satorius, EH Ye, Z Ely, T GP IEEE IEEE TI Carrier acquisition and tracking requirements for Doppler navigation SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper studies feasibility of using one-way and two-way Doppler to accomplish rendezvous for Mars Sample Return project. Acquisition and tracking requirements of the second and third order phase-locked loop (PLL) under flight and rotational dynamics conditions is presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Satorius, EH (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1631 EP 1638 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700165 ER PT S AU Redding, DC Shi, F Basinger, SA Cohen, D Green, JJ Lowman, AE Ohara, CM AF Redding, DC Shi, F Basinger, SA Cohen, D Green, JJ Lowman, AE Ohara, CM GP IEEE IEEE TI Wavefront sensing and control for large space optics SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Large space optical systems will require on-orbit wavefront sensing and control systems to correct misalignments and figure errors incurred during manufacture, launch and deployment. This paper describes key WFS&C technologies developed to support the James Webb Space Telescope, Terrestrial Planet Finder, and Actuated Hybrid Mirror Telescope missions. C1 NASA, Jet Prop Lab, CALTECH, Pasadena, CA 91109 USA. RP Redding, DC (reprint author), NASA, Jet Prop Lab, CALTECH, 4800 Oak Grove Dr,MS 306-438, Pasadena, CA 91109 USA. NR 31 TC 3 Z9 3 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 1729 EP 1744 PG 16 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700176 ER PT S AU Alvarez-Salazar, OS Goullioud, R AF Alvarez-Salazar, OS Goullioud, R GP IEEE IEEE TI Combined feed-forward and feedback control for dim star fringe tracking on the SIM test-bed 3 SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID INTERFEROMETER; DESIGN AB Future space-based optical interferometers such as the Space Interferometer Mission (SIM) require fringe stabilization to the level of nanometers in order to produce astrometric data at the micro-arc-second level. Active pathlength control is usually implemented to compensate for the attitude drift of the spacecraft. This issue has,been addressed in previous experiments while tracking bright stars. In the case of dim stars, as the sensor bandwidth falls below one hertz, feedback control provides limited rejection. However, stabilization of the fringes from a dim star down to the nanometer level can also be done open loop using the information from additional interferometers looking at bright guide stars. The STB3 testbed developed at the Jet Propulsion Laboratory features three optical interferometers sharing a common baseline, dynamically representative of the SIM interferometer. An artificial star feeding the interferometers is installed on a separate optics bench. Voice coils are used to simulate the attitude motion of the spacecraft by moving the entire bench. Data measured on STB3 shows that the fringe motion of a dim star due to the spacecraft attitude change can be attenuated by more than 100dB at 0.01Hz using a combination of a slow feedback and a fast feed-forward control using information from the two guide stars. This paper will describe the STB3 setup, the pathlength control architecture and the data collected with the system and how they relate to SIM. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Alvarez-Salazar, OS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 171-113, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2191 EP 2203 PG 13 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700217 ER PT S AU Goullioud, R Hines, BE Bell, CE Shen, TJ Bloemhof, EE AF Goullioud, R Hines, BE Bell, CE Shen, TJ Bloemhof, EE GP IEEE IEEE TI SIM astrometric demonstration at the 150 picometer level using the MAM testbed SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Future space-based optical interferometers, such as the Space Interferometer Mission (SIM), require fringe measurements to the level of picometers in order to produce astrometric data at the micro-arc-second level. To be more specific, it is necessary to measure both the position of the starlight central fringe and the change in the internal optical path of the interferometer to a few tens of picometers. The internal path is measured with a small metrology beam, whereas the starlight fringe position is estimated with a CCD sampling a large concentric annular beam. One major challenge for SIM is to align the metrology beam with the starlight beam to keep the consistency between these two sensors at the system level. The Micro-Arcsecond Metrology testbed (MAM) developed at the Jet Propulsion Laboratory features an optical interferometer with a white light source, all major optical components of a stellar interferometer, and heterodyne metrology sensors. The setup is installed inside a large vacuum chamber in order to mitigate atmospheric and thermal disturbances. Recent data show agreement between the metrology and starlight paths to better than 150 pm in the narrow field of view of SIM. This paper describes the MAM optical setup, the alignment process, the current data, and how the performance relates to SIM. C1 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2217 EP 2235 PG 19 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700219 ER PT S AU Regehr, MW Hines, B Holmes, B AF Regehr, MW Hines, B Holmes, B GP IEEE IEEE TI Optical path control in the MAM testbed SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Future space-based optical interferometers, will require control of the optical path delay to accomplish some or all of three objectives: balancing the optical path in the two arms to within a tolerance corresponding to the coherence length of the star light being observed, modulating the optical path in order to observe the phase of the star light interference fringe, and modulating the path length in order to reduce the effect of cyclic errors in the laser metrology system used to measure the optical path length in the two arms of the interferometer. In the Micro-Arcsecond Metrology (MAM) test bed, three types of actuator are used to control the optical path delay: a coarse actuator consisting of a stepper-motor-driven translation stage supporting a corner cube, a balanced voice coil modulator driving a flat mirror, and two flat mirrors mounted on tripod PZT actuators. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Regehr, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 171-113, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2237 EP 2242 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700220 ER PT S AU Serabyn, E Mennesson, B AF Serabyn, E Mennesson, B GP IEEE IEEE TI Pupil configurations for an interferometric TPF mission SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID NULLING INTERFEROMETER; EXTRASOLAR PLANETS; SEARCH AB The primary goal of the proposed Terrestrial Planet Finder (TPF) mission [1] is the direct detection of radiation from potential terrestrial planets orbiting around nearby stars. However, the faintness of the expected signals leads to very stringent technical requirements on the optical performance. As a result, both of the candidate approaches currently under active development by the TPF project, infrared nulling interferometry with separated aperture telescopes, and optical coronagraphy with a large single aperture telescope, require complex optical systems which push the state of the art. Identification of the simplest optical approach, as well as laboratory demonstrations of the basic capabilities, are therefore essential. In this paper, the range of proposed interferometric architectures is briefly summarized and compared. On this basis, it is concluded that a fairly simple, compact linear array of telescopes on a structure, such as a chopped dual-Bracewell system, can attain the bulk of the goals set out for the TPF mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Serabyn, E (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2259 EP 2265 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700222 ER PT S AU Rakow, G Schnurr, R Dailey, C Shakoorzadeh, K AF Rakow, G Schnurr, R Dailey, C Shakoorzadeh, K GP IEEE IEEE TI Reliable transport over SpaceWire for James Webb space telescope SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA's James Webb Space Telescope (JWST) faces difficult technical and budgetary challenges to overcome before it is scheduled launch in 2010. The Integrated Science Instrument Module (ISIM), shares these challenges. The major challenge addressed in this paper is the data network used to collect, process, compresses and store Infrared data. A total of 114 Mbps of raw information must be collected from 19 sources and delivered to the two redundant data processing units across a twenty meter deployed thermally restricted interface. Further data must be transferred to the solid-state recorder and the spacecraft. The JWST detectors are kept at cryogenic temperatures to obtain the sensitivity necessary to measure faint energy sources. The Focal Plane Electronics (FPE) that sample the detector, generate packets from the samples, and transmit these packets to the processing electronics must dissipate little power in order to help keep the detectors at these cold temperatures. Separating the low powered front-end electronics from the higher-powered processing electronics, and using a simple high-speed protocol to transmit the detector data minimize the power dissipation near the detectors. Low Voltage Differential Signaling (LVDS) drivers were considered an obvious choice for physical layer because of their high speed and low power. The mechanical restriction on the number cables across the thermal interface force the Image packets to be concentrated upon two high-speed links. These links connect the many image packet sources, Focal Plane Electronics (FPE), located near the cryogenic detectors to the processing electronics on the spacecraft structure. From 12 to 10,000 seconds of raw data are processed to make up an image, various algorithms integrate the pixel data Loss of commands to configure the detectors as well as the loss of science data itself may cause inefficiency in the use of the telescope that are unacceptable given the high cost of the observatory. This combination of requirements necessitates a redundant/fault tolerant highspeed, low mass, low power network with a low Bit error Rate (1E-9 - 1E-12). The ISIM systems team performed many studies of the various network architectures that meeting these requirements. The architecture selected uses the SpaceWire protocol, with the addition of a new transport and network layer added to implement end-to-end reliable transport. The network and reliable transport mechanism must be implemented in hardware because of the high average information rate and the restriction on the ability of the detectors to buffer data due to power and size restrictions. This network and transport mechanism was designed to be compatible with existing SpaceWire links and routers so that existing equipment and designs may be leveraged upon. The transport layer specification is being coordinated with European Space Agency (ESA), SpaceWire Working Group and the Consultative Committee for Space Data System (CCSDS) PIK Standard Onboard Interface (SOIF) panel, with the intent of developing a standard for reliable transport for SpaceWire. Changes to the protocol presented are likely since negotiations are ongoing with these groups. A block of RTL VHDL that implements a multi-port SpaceWire router with an external user interface will be developed and integrated with an existing SpaceWire Link design. The external user interface will be the local interface that sources and sinks packets onto and off of the network (Figure 3). The external user interface implements the network and transport layer and handles acknowledgements and re-tries of packets for reliable transport over the network. Because the design is written in RTL, it may be ported to any technology but will initially be targeted to the new Actel Accelerator series (AX) part. Each link will run at 160 Mbps and the power will be about 0.165 Watt per link worst case in the Actel AX. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rakow, G (reprint author), NASA, Goddard Space Flight Ctr, Code 561, Greenbelt, MD 20771 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2289 EP 2302 PG 14 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700225 ER PT S AU Blue, RC Bolotin, GS AF Blue, RC Bolotin, GS GP IEEE IEEE TI X2000 Advanced Avionics Project development of a new generation of avionics for space applications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The X2000 Advanced Avionics Project has developed a new generation of avionics building block modules for use by multiple deep space missions, including future missions to Europa, Mars, and a comet. The key developments of the X2000 Avionics are a high performance flight computer, solid-state mass data storage, high-speed system I/O, solid-state power distribution, and power regulation and conversion. These components enable a modular and scalable design approach that results in a wide variety of avionics system architectures to meet diverse mission requirements and environments. The X2000 Avionics have been developed for use in extreme radiation environments such as those at Jupiter. The use of commercial standard interfaces and buses throughout the X2000 Avionics allow system designers to add functionality and further customize spacecraft architectures. This paper will describe the system architecture, the avionics components, the key performance and reliability requirements, and the current development status of the X2000 Avionics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Blue, RC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2303 EP 2314 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700226 ER PT S AU Abbott, L AF Abbott, L GP IEEE IEEE TI MiniAERCam avionics SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper describes the architecture of a small, seven and a half (7.5) inch diameter, free- flyer satellite called the Mni-AERCarn for Autonomous Extravehicular Robotic CAMera. NASA-JSC developed Mini-AERCam as a technology demonstrator for an astronaut assistant. This design allows inspections of the exteriors of the Space Shuttle or International Space Station, thereby reducing the number of Extra Vehicular Activities (EVA) and reducing crew workload. The paper focuses on the architectural aspects of the design philosophy used to successfully achieve the seemingly mutually exclusive requirements specified for the MiniAERCam. Key among the design approaches is the use of soft functions. Soft functions were used in the MiniAERCam to implement everything from peripherals to virtual Printed Circuit Board (PCB) traces. The paper discusses how soft functions can minimize the interactions between detail peripheral development and board level hardware development. Additionally, the use of soft function serves as a unifying focus point for the system architect, software designers and hardware designers. The soft function is where hardware and software designs can meld together to optimize overall system performance. C1 NASA, JSC, Houston, TX 77058 USA. RP Abbott, L (reprint author), NASA, JSC, 2101 NASA Rd, Houston, TX 77058 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2329 EP 2334 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700228 ER PT S AU Day, L Meyer, D Nicolich, N Steele, R Uchenik, I Vines, K AF Day, L Meyer, D Nicolich, N Steele, R Uchenik, I Vines, K GP IEEE IEEE TI Software performance on the X2000 Advanced Avionics SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The X2000 Advanced Avionics project at JPL was created to provide the core spacecraft avionics for use on multiple future missions. The avionics suite includes a radiation hardened PPC 750 as well as various I/O and mass storage devices. A key factor in modem computer architectures is the fact that the CPU operates much faster than does the main memory. This has necessitated caching techniques to obtain full performance from the processor, and has also made software performance highly dependent on cache activity. This dependency on cache activity makes it more difficult to predict whether a given application will perform as expected on a given platform. Simple benchmarks are of limited use since the cache behavior is generally predictable and therefore does not accurately reflect the behavior of a more complex application. A "X2000 Advanced Avionics Characterization Study" was performed in which a set of tests were run, beginning with single tests of both CPU intensive and I/O intensive activities. These tests were then run in combination to build up to a very active complex computing environment in order to expose performance interactions. This should then provide a wide enough range of examples to allow a potential user to more accurately estimate the expected performance of their application. Measurements were collected on a per-task basis for the actual execution rate and cache performance by using the Power PC 750 performance monitoring registers. The characterization study has shown that adjustments in an application's data accesses can easily create a performance difference of three or more times in actual applications. In general, by iterating over a small portion of a data set rather than its entirety, execution can remain within cache thereby producing a performance increase. Additionally, the approaches used in performing I/O can make a major performance difference. As system activity increases, differences are seen in an application's cache performance, but this factor affects performance much less than do issues specific to the way a particular application accesses memory and performs I/O. Contention for the PCI bus can also be a performance issue to consider. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Day, L (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2471 EP 2479 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700245 ER PT S AU Patterson, RL Dickman, JE Hammoud, A Gerber, S AF Patterson, RL Dickman, JE Hammoud, A Gerber, S GP IEEE IEEE TI Electronic components and circuits for extreme temperature environments SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Planetary exploration missions and deep space probes require electrical power management and control systems that are capable of efficient and reliable operation in very low temperature environments. Presently, spacecraft operating in the cold environment of deep space carry radioisotope heating units in order to maintain the surrounding temperature of the on-board electronics at approximately 20 degreesC. Electronics capable of operation at cryogenic temperatures will not only tolerate the hostile environment of deep space but also reduce system size and weight by eliminating or reducing the radioisotope heating units and their associate structures; thereby reducing system development as well as launch costs. In addition, power electronic circuits designed for operation at low temperatures are expected to result in more efficient systems than those at room temperature. This improvement results from better behavior and tolerance in the electrical and thermal properties of semiconductor and dielectric materials at low temperatures. The Low Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electrical components, circuits, and systems suitable for applications in the aerospace environment and deep space exploration missions. Research is being conducted on devices and systems for reliable use down to cryogenic temperatures (as low as -243 degreesC or 30 K). Some of the commercial-off-the-shelf as well as developed components that are being characterized include passive and active devices and circuits. An overview of the NASA Glenn Research Center Low Temperature Electronic Program will be presented in this paper. A description of the low temperature test facilities along with selected data obtained through in-house component and circuit testing will also be discussed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, MS 301-5, Cleveland, OH 44135 USA. EM Richard.Patterson@grc.nasa.gov; John.Dickman@grc.nasa.gov; Ahmad.Hammoud@grc.nasa.gov; Scott.Grerber@grc.nasa.gov NR 11 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2543 EP 2548 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700253 ER PT S AU Stoica, A Zebulum, RS Ferguson, MI Keymeulen, D Duong, V Daud, T Guo, X AF Stoica, A Zebulum, RS Ferguson, MI Keymeulen, D Duong, V Daud, T Guo, X GP IEEE IEEE TI Evolutionary configuration of field programmable analog devices SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID EVOLVABLE HARDWARE; ARRAYS AB The purpose of this paper is to illustrate evolution of analog circuits on a stand-alone board-level evolvable system (SABLES). SABLES is part of an effort to achieve integrated evolvable systems. SABLES provides autonomous, fast (tens to hundreds of seconds), on-chip circuit reconfiguration. Its main components are a JPL Field Programmable Transistor Array (FPTA) chip used as transistor-level reconfigurable hardware, and a TI DSP that implements the evolutionary algorithm controlling the FPTA reconfiguration. The paper details an example of evolution on SABLES and points out to certain transient and memory effects that affect the stability of solutions obtained reusing the same piece of hardware for rapid testing of individuals during evolution. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM adrian.stoica@jpl.nasa.gov 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2565 EP 2572 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700256 ER PT S AU Liebe, CC Abramovici, A Bartman, RK Bunker, RL Chapsky, J Chu, CC Clouse, D Dillon, JW Hausmann, B Hemmati, H Kornfeld, RP Kwa, C Mobasser, S Newell, M Padgett, C Roberts, WT Spiers, G Warfield, Z Wright, M AF Liebe, CC Abramovici, A Bartman, RK Bunker, RL Chapsky, J Chu, CC Clouse, D Dillon, JW Hausmann, B Hemmati, H Kornfeld, RP Kwa, C Mobasser, S Newell, M Padgett, C Roberts, WT Spiers, G Warfield, Z Wright, M GP IEEE IEEE TI Laser radar for spacecraft guidance applications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A flight qualified laser radar called LAMP (LAser MaPper) is under development at JPL. LAMP is a guidance and control sensor that can form 3 dimensional images of its field of regard. The maps can be used for spacecraft rendezvous, docking, and hazard avoidance during landing and for rover traverse planning. LAMP operates by emitting high power, short duration laser pulses, which are directed by an internal gimbaled mirror in azimuth and elevation. When the laser pulses impinge on a surface, a small amount of the light is reflected back to the sensor and is collected by a telescope. On the way out, a laser actuated trigger starts a counter that is stopped by the return pulse. The counter value (time of flight) is proportional to the distance to the object. This paper describes the detailed design of the LAMP sensor. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM carl.c.liebe@jpl.nasa.gov NR 11 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2647 EP 2662 PG 16 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700263 ER PT S AU Gat, E AF Gat, E GP IEEE IEEE TI Architecture, language, and non-compositional constraints SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB In the realm of building construction and computer hardware, the word "architecture" means a set of features shared by a class of designs, or equivalently, a set of constraints on a class of designs (e.g. gothic architecture or RISC architecture). But in the realm of software, the meaning of "architecture" has changed to be more or less synonymous with "design." This is unfortunate because the concept of architecture- as- constraint is potentially useful: properly chosen constraints can guide engineers towards good designs and away from bad ones (and, of course, poorly chosen constraints can have the opposite effect). We can identify two distinct classes of architectural constraints. Compositional constraints are constraints on the structure of a software system, while non-compositional constraints are constraints on the mechanisms for constructing that structure. On this view, "structured programming", for example, is an architecture that imposes non-compositional constraints on the use of the GOTO statement. The concept of non-compositional constraints has been largely ignored by the software engineering community. This has been in some cases a serious impediment to progress. For example, the JPL Mission Data System (MDS) is an architecture based on the non-compositional constraint that spacecraft should be controlled using goals, which are defined as constraints on state variables over time intervals. This is a very simple and straightforward concept with significant benefits, but because it is a non-compositional constraint and therefore unfamiliar, MDS has not been received with unalloyed enthusiasm. This paper offers an informal discussion of non-compositional constraints (NCC) in hopes of making the concept more familiar and accessible. It describes the relationship of NCC and programming languages, and the applicability of the concept to the problem of verification and validation of spacecraft autonomy software. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Gat, E (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 2875 EP 2880 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700285 ER PT S AU Park, HG Zak, M AF Park, HG Zak, M GP IEEE IEEE TI Model reconstruction using POD method for gray-box fault detection SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper describes using the Proper Orthogonal Decomposition (POD) method to create low-order dynamical models for the Model Filter component of Beacon-based Exception Analysis for Multi-missions (BEAM). The POD modeling procedure is described, and its usefulness in creating simple low-order dynamical models of a complex system. The POD procedure will be shown on an example problem of Burgers' Equation. It will be demonstrated that stable low-order dynamical models can be created even in the presence of noise commonly found in experimental data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Park, HG (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3087 EP 3093 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700308 ER PT S AU Fletcher, DP Alena, R AF Fletcher, DP Alena, R GP IEEE IEEE TI A scalable, out-of-band diagnostics architecture for International Space Station systems support SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The computational infrastructure of the International Space Station (ISS) is a distributed system that supports multiple vehicle subsystems such as Caution and Warning, Electrical Power System and Command and Data Handling (C&DH), as well as scientific payloads of varying size and complexity. The dynamic nature of the ISS configuration coupled with the increased demand for payload support places a significant burden on the inherently resource constrained computational infrastructure of the ISS. Onboard system diagnostics applications are hosted on computers that are elements of the avionics network while ground-based diagnostic applications receive only a subset of available telemetry, down-linked via Sband communications. In this paper we propose a scalable, out-of-band diagnostics architecture for ISS systems support that uses a read-only connection for C&DH data acquisition, which provides a lower cost of deployment and maintenance (versus a higher criticality read/write connection). The diagnostics processing burden is off-loaded from the avionics network to elements of the on-board LAN that have a lower overall cost of operation and increased computational capacity. A superset of diagnostic data, richer in content than the configured telemetry, is made available to Advanced Diagnostic System (ADS) clients running on wireless handheld devices, affording the crew greater mobility for troubleshooting and providing improved insight into vehicle state. The superset of diagnostic data is made available to the ground in near real-time via an out-of band downlink, providing a high level of fidelity between vehicle state and test, training and operational facilities on the ground. C1 Sci Applicat Int Corp, NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Fletcher, DP (reprint author), Sci Applicat Int Corp, NASA, Ames Res Ctr, Moffett Field, CA 94035 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3381 EP 3391 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700337 ER PT S AU Childs, D AF Childs, D GP IEEE IEEE TI Information technology security system engineering methodology SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB A methodology is described for system engineering security into large information technology systems under development. The methodology is an integration of a risk management process and a generic system development life cycle process. The methodology is to be used by Security System Engineers to effectively engineer and integrate information technology security into a target system as it progresses through the development life cycle. The methodology can also be used to re-engineer security into a legacy system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Childs, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 230-305, Pasadena, CA 91109 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3393 EP 3401 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700338 ER PT S AU Fragoso, RS Bryant, LW AF Fragoso, RS Bryant, LW GP IEEE IEEE TI Training and verification for risk reduction on the new classes of missions at NASA's Jet Propulsion Laboratory SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The focus on improving and increasing planetary exploration with lower cost missions and the unfortunate incidents of the not so distant past point to a need for risk reduction without budget inflation. To satisfy this need requires a robust program well founded in standardized practices with standards of performance. Standardized practices facilitate repeating successful projects without recreating all of the original work that led to the initial success. Standards provide a means to measure progress and gauge performance in relation to levels that result in success. By developing, within the Jet Propulsion Laboratory's (JPL) Mission Management Office (MMO), a core program of standardized training and verification practices and standards against which the implementation of these practices can be measured, we expect to provide an affordable resource for project risk reduction in key areas. The importance of well prepared individuals, teams, and a Mission Operations System (MOS) as the cornerstone in improving the likelihood of success and reducing risk is the focus of our program. We address individual position training and certification for operations, team rehearsals of operations processes, verification of MOS interfaces, and operations readiness testing to verify the MOS processes, functionality, and operability. These areas are addressed initially through the development of specifications and guidelines that span the breadth of JPL projects. Beyond the guidance is practical assistance through templates for training plans, rehearsals, and readiness tests as well as training modules. The training modules will cover knowledge requirements common to all projects, tools used to conduct operations, and project specific knowledge. Modules will be developed for delivery in tutorial and lecture modes with a future option for on demand, computer based delivery. With the core program in place, it will be easier for projects to afford an effective training and verification effort which can be adapted to the unique attributes of their flight project and improve the risk reduction effort essential to mission success. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Fragoso, RS (reprint author), 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3413 EP 3418 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700340 ER PT S AU Jaap, J Richardson, L Davis, E AF Jaap, J Richardson, L Davis, E GP IEEE IEEE TI Maximally expressive modeling of operations tasks SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Planning and scheduling systems organize ''tasks'' into a timeline or schedule. The tasks are defined within the scheduling system in logical containers called models. The dictionary might define a model of this type as ''a system of things and relations satisfying a set of rules that, when applied to the things and relations, produce certainty about the tasks that are being modeled.'' One challenging domain for a planning and scheduling system is the operation of on-board experiments for the International Space Station. In these experiments, the equipment used is among the most complex hardware ever developed, the information sought is at the cutting edge of scientific endeavor, and the procedures are intricate and exacting. Scheduling is made more difficult by a scarcity of station resources. The models to be fed into the scheduler must describe both the complexity of the experiments and procedures (to ensure a valid schedule) and the flexibilities of the procedures and the equipment (to effectively utilize available resources). Clearly, scheduling International Space Station experiment operations calls for a "maximally expressive" modeling schema. RP Jaap, J (reprint author), NASA, George C Marshall Space Flight Ctr, Ground Syst Dept, Mission Support Syst Grp,Flight Projects Director, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3465 EP 3474 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700346 ER PT S AU Lee, CH Cheung, KM AF Lee, CH Cheung, KM GP IEEE IEEE TI Power, data latency, and radio frequency interference issues in Mars relay network scheduling SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Mars will be continuously crowded this decade and beyond with many missions. Along with the current orbiters of Mars Global Surveyor and Odyssey 2001, future Mars missions within the next few years include Mars Exploration Rovers, Mars Express, and Mars Beagle in 2003, Mars Reconnaissance Orbiter in 2005, Mars Premier Netlanders, Mars Scouts in 2007, and Mars Smart Lander in 2009. At different time periods in the future, these missions are overlapped. Previous studies indicate that during such periods, existing deep space communication infrastructure cannot handle all Mars communication needs. There has been much coordination between various Mars projects and the Deep Space Network to ensure communication resources are effectively utilized so that valuable science and engineering data from Mars orbiters and landers can be accommodated. A plausible solution is to take into account the end-to-end communication performances of network alone, with operational constraints, and optimize the resource usage by scheduling communication at highest possible data throughputs. As a result, shorter communication time is required and more missions can be accommodated. This principle is demonstrated in this paper for a Mars relay communication network; a network consisting of multiple surface units and orbiters on Mars and the Deep Space Stations. A relay communication network around Mars can increase the overall science data return of the surface elements, reduce surface elements' direct-to-earth communication demands, and enable communication even when the surface elements are not facing Earth. It is the objective of this paper to take advantage of the relay operation to efficiently plan and schedule the network communications. Our previous results in relay network planning and scheduling include (i) modeling and simulating the overall end-to-end network link capabilities as time-varying resources by incorporating spacecraft dynamics, telecom configurations and other limiting factors such as planet occultation, weather, etc.; (ii) developing mathematical formulations for operational constraints such as daylight operations, one-to-one communication, time for acquisition and calibration, science data volume return requirement, onboard storage capacity, etc; (iii) formulating and solving, the Mars relay network planning and scheduling as linear and nonlinear constrained optimization problem. In this paper, we address several issues that arise in Mars relay network operations. Major operation issues that we investigate in this paper include radio frequency interference, surface unit's battery limitations, and data return latency. Particularly, we (a) develop mathematical conditions, based on the geometry of the orbiters and surface units, to identify links with potential radio frequency interference and impose constraints on the links so that the optimal network scheduling is free from interference; (b) impose both the Sun angle constraint and the transmission duration constraint on the surface unit's battery; and (c) associate each orbiter with a latency function that allows the surface unit to judiciously select its orbiter to minimize the data latency. Numerical studies for a sample Mars relay network will also be presented. 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3513 EP 3524 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700350 ER PT S AU Backes, PG Norris, JS Powell, MW Vona, MA Steinke, R Wick, J AF Backes, PG Norris, JS Powell, MW Vona, MA Steinke, R Wick, J GP IEEE IEEE TI The science activity planner for the Mars Exploration Rover mission: FIDO field test results SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The science activity planning process for the 2003 Mars Exploration Rover (MER) mission was exercised in a ten day terrestrial rover field test in August 2002. A version of the MER mission Science Activity Planner (SAP) tool was used for downlink data visualization and uplink plan generation. The Field Integrated Design and Operations (FIDO) rover was at an undisclosed location in the Arizona desert. Data from the rover was sent via satellite to scientists and engineers at JPL who used SAP to generate uplink sequences. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Backes, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3525 EP 3539 PG 15 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700351 ER PT S AU Vona, MA Backes, PG Norris, JS Powell, MW AF Vona, MA Backes, PG Norris, JS Powell, MW GP IEEE IEEE TI Challenges in 3D visualization for Mars Exploration Rover mission science planning SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Science Activity Planner (SAP), currently under development by our group at the Jet Propulsion Laboratory, will be the primary tool used for science data assessment and science activity planning during the Mars Exploration Rover (MER) mission. As part of its data visualization capability, SAP interactively displays 3D terrain surface data corresponding to the MER image data products. These datasets can be very large, e.g. on the order of tens of millions of vertices for a panorama, so it is a challenge to load and display them at interactive speeds on a workstation. We describe the software techniques we are implementing to address this challenge and present recent test results. A fundamental development is the new Visible Scalable Terrain (ViSTA) format, a flexible and precise interchange format for terrain data. Other developments include multi-threaded asynchronous event-driven data loading, practical heuristics for geometry LOD and texture resolution selection, multilevel garbage-collector friendly data caching, and an optimized. ray intersection system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM vona@jpl.nasa.gov 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3541 EP 3551 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700352 ER PT S AU Townes, SA Amoozegar, F Border, JS Breidenthal, JC Morabito, D Moyd, KI Patterson, JE Shambayati, S AF Townes, SA Amoozegar, F Border, JS Breidenthal, JC Morabito, D Moyd, KI Patterson, JE Shambayati, S GP IEEE IEEE TI Operational demonstration of Ka-band telecommunications for the Mars Reconnaissance Orbiter SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The NASA Mars Reconnaissance Orbiter Project and the NASA Interplanetary Network Directorate are collaborating to establish the first operational use of Ka-and for telemetry and navigation in a deep space application. The objectives of the operational demonstration are to verify that the anticipated benefits of the higher carrier frequency can actually be realized under realistic operating conditions, and if possible to provide a significant enhancement to scientific data return. We anticipate being able to demonstrate Ka-band data rates in the range 0.5 to 4.0 Mbps depending on Earth-Mars distance. We also anticipate demonstration of significant improvements in the accuracy of round-trip Doppler, ranging, and differenced differential one-way range (delta-DOR). The major open issues to be addressed in the coming year of design activities are: further characterization of weather statistics; selection of the operational methods to manage weather-induced uncertainties of link performance; the ability to consistently point large ground antennas without residual carrier signals; the performance and pointing of a large spacecraft antenna on a dynamic spacecraft; the best methods of utilizing the ground and spacecraft data system resources for optimization of data return; and the construction of a Ka-band radio source catalog. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Townes, SA (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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3565 EP 3580 PG 16 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700354 ER PT S AU Grasso, CA AF Grasso, CA GP IEEE IEEE TI Techniques for simplifying operations using VML (Virtual Machine Language) sequencing on Mars Odyssey and SIRTF SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB VML (Virtual Machine Language) is an advanced procedural sequencing language which simplifies spacecraft operations, minimizes uplink product size, and allows autonomous operations aboard a mission without the development of autonomous flight software. VML is used on Mars Odyssey and Space Infrared Telescope Facility, and is slated for use on Mars Reconnaissance Orbiter. The language is a mission-independent, high level, human readable script. It features a rich set of data types (including integers, doubles, and strings), named functions, parameters to functions, IF and WHILE control structures, polymorphism, and on-the-fly creation of spacecraft commands from calculated values. The ground component of VML consists of a mission-independent compiler, a data-driven command generator, and an execution tool, all of which run under Unix. The compiler translates human readable source to a binary format. The data-driven command generator translates mission-specific spacecraft commands for the compiler from human-readble text to binary. The offline sequence execution tool runs sequences at speeds several thousand times real-time, and provides debugging features, integrated reports, and interactive execution options. These tools allow iterative development of sequences with a turnaround time of seconds rather than the hours or days typical with full-up lab testing. Parameterization and use of reusable functions called blocks onboard the spacecraft has several advantages over ground expanded sequences. Mission safety is enhanced, since blocks receive more scrutiny up front during development. Development of sequences is simplified due to the rich set of behaviors that can be invoked from blocks. The review and test process for the invoking sequences is simplified because the behavior of the blocks is well understood. Mission costs for autonomy are reduced, since responses to conditions are coded into blocks and upgraded without changing flight software. Uplink load is reduced, as the blocks physically reside onboard the spacecraft. VML use on Mars Odyssey and the Space Infrared Telescope Facility (SIRTF) has allowed spacecraft operations teams to place autonomy aboard deep space missions. For instance, the Mars Odyssey team developed VML blocks which could react to autonomously detected unexpected blooming of the Martian atmosphere during aerobraking end-game to raise the spacecraft orbit to a safe altitude, without ground intervention. SIRTF is using VML functionality to gather more data during the mission by detecting when the facility has settled after a slew, rather than using worst-case settling times. SIRTF also uses VML to dynamically build spacecraft commands, dramatically reducing the size of uplink products and allowing the mission to live within its communications allocation. This paper discusses techniques for parameterizing routine operations using onboard blocks. The relationship between one-use sequences and reusable blocks is discussed. Reduced development effort due to iterative block development is outlined. The ability to migrate to the spacecraft functionality which is more traditionally implemented on the ground is examined. The implications for implementing spacecraft autonomy without the need for expensive flight software agent development is also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grasso, CA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-250D, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3603 EP 3613 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700357 ER PT S AU Streiffert, BA Polanskey, CA O'Reilly, T Colwell, J AF Streiffert, BA Polanskey, CA O'Reilly, T Colwell, J GP IEEE IEEE TI Science Opportunity Analyzer - A multi-mission approach to science planning SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB In the past Science Planning for space missions has been comprised of using ad-hoc software tools collected or reconstructed from previous missions, tools used by other groups who often speak a different "technical" language or even "the backs of envelopes." In addition to the tools being rough, the work done with these tools often has had to be redone or at least re-entered when it came time to determine actual observations. Science Opportunity Analyzer (SOA), a Java-based application, has been built for scientists to enable them to identify/analyze observation opportunities and then to create corresponding observation designs for orbiting, astronomical (telescope), and flyby missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Streiffert, BA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-250D, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3615 EP 3627 PG 13 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700358 ER PT S AU Castano, R Anderson, RC Estlin, T DeCoste, D Fisher, F Gaines, D Mazzoni, D Judd, M AF Castano, R Anderson, RC Estlin, T DeCoste, D Fisher, F Gaines, D Mazzoni, D Judd, M GP IEEE IEEE TI Rover traverse science for increased mission science return SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Rover traverse distances are increasing at a faster rate than downlink capacity is increasing. As this trend continues, the quantity of data that can be returned to Earth per meter traversed is reduced. The capacity of the rover to collect data, however, remains high. This circumstance leads to an opportunity to increase mission science return by carefully selecting the data with the highest science interest for downlink. We have developed an onboard science analysis technology for increasing science return from missions. Our technology evaluates the geologic data gather by the 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 the identified science opportunity. Although our techniques are applicable to a wide range of data modalities, our initial emphasis has focused on image analysis, since images consume a large percentage of downlink bandwidth. We have further focused our foundational work on rocks. Rocks are among the primary features populating the Martian landscape. Characterization and understanding of rocks on the surface is a first step leading towards more complex in situ regional geological assessments by the rover. C1 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 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 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3629 EP 3636 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700359 ER PT S AU Doody, D AF Doody, D GP IEEE IEEE TI Cassini/Huygens: Heavily instrumented flight systems approaching Saturn and Titan SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Cassini and Huygens flight systems are described including capabilities, launch, flight path, mission science objectives, and instruments. Interplanetary cruise, Saturn arrival, and science-tour operations are also discussed, including use of JPL's worldwide Deep Space Network for two-way communications. Launched 15 October 1997, Cassini/Huygens will arrive at the Saturnian system on 1 July 2004. The Cassini Orbiter begins a four-year tour of the ringed gas giant, and the Huygens Probe descends through Titan's dense atmosphere on 14 January 2005. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Doody, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 230-310, 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3637 EP 3646 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700360 ER PT S AU Karpati, G Martin, J Steiner, M Reinhardt, K AF Karpati, G Martin, J Steiner, M Reinhardt, K GP IEEE IEEE TI The Integrated Mission Design Center (IMDC) at NASA Goddard Space Flight Center SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA Goddard has used its Integrated Mission Design Center (IMDC) to perform more than 150 mission concept studies. The EADC performs rapid development of high-level, end-to-end mission concepts, typically in just 4 days. The approach to the studies varies, depending on whether the proposed mission is near-future using existing technology, mid-future using new technology being actively developed, or far-future using technology which may not yet be clearly defined. The emphasis and level of detail developed during any particular study depends on which timeframe (near-, mid-, or far-future) is involved and the specific needs of the study client. The most effective mission studies are those where mission capabilities required and emerging technology developments can synergistically work together; thus both enhancing mission capabilities and providing impetus for ongoing technology development. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Karpati, G (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3657 EP 3667 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700362 ER PT S AU Cornford, SL Feather, MS Dunphy, JR Salcedo, J Menzies, T AF Cornford, SL Feather, MS Dunphy, JR Salcedo, J Menzies, T GP IEEE IEEE TI Optimizing spacecraft design - Optimization engine development: Progress and plans SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE Aerospace Conference Proceedings LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB At JPL and NASA, a process has been developed to perform life cycle risk management. This process requires users to identify: goals and objectives to be achieved (and their relative priorities), the various risks to achieving those goals and objectives, and options for risk mitigation (prevention, detection ahead of time, and alleviation). Risks are broadly defined to include the risk of failing to design a system with adequate performance, compatibility and robustness in addition to more traditional implementation and operational risks. The options for mitigating these different kinds of risks can include architectural and design choices, technology plans and technology back-up options, test-bed and simulation options, engineering models and hardware/software development techniques and other more traditional risk reduction techniques. Each of these risk mitigations has resource costs associated with them. The sum of all these mitigations is almost always unaffordable. Furthermore, there may be a variety of other constraints (mass, power, funding profile, leveraged programs, etc.) that further constrain acceptable selections. The challenge is therefore to emerge with an "optimal" selection of mitigations that makes best use of available resources to reduce risk to the fullest extent possible. For non-trivial design spaces, the search space of possible selections is huge. This precludes exhaustive search for the optimum, and therefore necessitates the adoption of heuristic search techniques. At JPL, we have explored application of several heuristic techniques for searching for, and refining, collections of risk mitigations, notably: genetic algorithms, simulated annealing, and machine learning. The results of research and pilot applications of these techniques for finding best combinations of life cycle risk management solutions are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Steven.L.Cornford@Jpl.Nasa.Gov; Martin.S.Feather@Jpl.Nasa.Gov; Julia.R.Dunphy@Jpl.Nasa.Gov; Jose.Salcedo@Jpl.Nasa.Gov; tim@menzies.com NR 10 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3681 EP 3690 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700364 ER PT S AU Kordon, M Wood, E AF Kordon, M Wood, E GP IEEE IEEE TI Multi-mission space vehicle subsystem analysis tools SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID MARS AB Spacecraft engineers often rely on specialized simulation tools to facilitate the analysis, design and operation of space systems. Unfortunately, these tools are often designed for one phase of a single mission and cannot be easily adapted to other phases or other missions. This frequently results in time consuming and costly redevelopment since the models need to be reworked, reverified and revalidated whenever there is an unexpected change. The Multi-Mission Space Vehicle Subsystem Analysis Tools are designed to provide a solution to this problem. Enabled by the recent increases in commodity computer storage capacity and computation speed, and leveraging off the fact that properly parameterized models can support multiple missions and that each phase differs primarily in the level of detail, these tools are able to provide a robust solution to space vehicle trade studies, performance analysis and sequence development, in a package that is easy-to-use and provides fast, accurate results at a level of fidelity appropriate to each stage of the project lifecycle. C1 Jet Prop Lab, Pasadena, CA 91001 USA. RP Kordon, M (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91001 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3699 EP 3705 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700366 ER PT S AU Lee, M Weidner, RJ Wang, SY Lininger, BM AF Lee, M Weidner, RJ Wang, SY Lininger, BM GP IEEE IEEE TI Science-return modeling and simulation SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Mission system designers formulate subsystem performance requirements based on the science-return objectives of a mission. The overall system architecture is optimized through inter subsystem performance trade-off analysis. Design optimization with respect to the entire mission life cycle is also greatly desired in order to reduce the overall mission development cycle and operational risk. To facilitate the life-cycle-wide design validation process, the Mission Simulation and Instrument Modeling (MSIM) group at the Jet Propulsion Laboratory (JPL) has been developing mission operation modeling methods and operation-behavior simulation system architectures. The modeling and simulation efforts have been applied to science-return probability analysis as well as to science scenario optimization. In this paper, an on-going effort to integrate science-return modeling and simulation with JPL's institutional mission system design process will be presented. The integration will enable science-return validation at each stage of the design process. Science-return modeling and simulation will be discussed with respect to science-centric mission system representation, science scenario generation, and operation-behavior synthesis and analysis. C1 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 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3719 EP 3730 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700368 ER PT S AU White, AL AF White, AL GP IEEE IEEE TI Mean time to unsafe failure for Markov, semi-Markov, and globally time dependent models SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB With the increased use of automatic equipment, electronics, and networks comes a concern about their failure modes. If they fail it is desirable that they fail in a benign manner. Hence, a reliability parameter of interest is the mean time to unsafe failure. The models and methods for computing this mean, however, are still in an early stage. This paper presents new material that permits examining more complex and realistic models. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3739 EP 3747 PG 9 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700370 ER PT S AU Mendoza, DR Johnson, R AF Mendoza, DR Johnson, R GP IEEE IEEE TI A leveraged approach to systems management in a highly diversified government research and development environment SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Minimizing a project's risk has always been a challenging problem, especially in the face of numerous and often conflicting requirements. In addition, challenges arise that are dependent on the projects' purpose and environment. The projects undertaken by the NASA Ames Research Center face these and many other challenges that are unique due to the institutional (Governmental), technological and scientific breadth (fundamental to applied research), and target application (space hardware/software, astrobiology, air transportation, and information technology) nature of their constraints. Thus, to address these challenges the Center formed a Systems Management Office (SMO) to improve and maintain competence in the areas of project management, systems engineering, and cost estimating. This paper describes an approach the SMO used that was based on leveraging a very small number of resources with existing Center expertise and best practices. This approach has enabled the SMO to balance its role between facilitation and consultation with independent assessment. The SMO's lessons learned, best practices, and results stemming from this leveraged approach are summarized. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mendoza, DR (reprint author), NASA, Ames Res Ctr, MS 200-1A, Moffett Field, CA 94035 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3763 EP 3768 PG 6 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700373 ER PT S AU Baroff, LE AF Baroff, LE GP IEEE IEEE TI Human factors in mission assurance SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Space projects rely completely on people for development and implementation-but project-related risk lists rarely include human factors as significant sources of risk. This paper is an attempt to identify and explain the important human factors that are related to mission success. The paper is based on interviews with Mission Assurance professionals, NASA and military reports and studies, and other literature. It identifies four types of human factors related to mission success: (1) adherence to processes and principles; (2) definition and fulfillment of roles, responsibilities, and relationships for organizations and individuals; (3) individual success factors and (4) communication within the project. There are examples of mission threats or mishaps from causes related to these factors. The paper notes mitigation techniques for risks associated with the human factors-readers are encouraged to come up with as many mitigation strategies as possible, and share them with each other!(1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Baroff, LE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3769 EP 3775 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700374 ER PT S AU Webster, J AF Webster, J GP IEEE IEEE TI The auditors are coming: A practical guide for engineering projects SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB When management informs you that internal or external auditors are on their way to conduct an audit of your project, you may have many questions and, at times, few answers: Why are the auditors coming? Why now? What are they looking for? How long will the audit take? What can we do to prepare? What help will the project receive in responding to the auditors? This paper presents a description of the typical audit process, a list of do's and don'ts for projects undergoing an audit, how to design basic audit preparations into the project's design, and resources for further information on auditing issues. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Webster, J (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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3777 EP 3784 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700375 ER PT S AU Mohan, SN AF Mohan, SN GP IEEE IEEE TI Designing a process for executing projects under an international agreentent SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Projects executed under an international agreement require special arrangements in order to operate within confines of regulations issued by the State Department and the Commerce Department. In order to communicate enterprise-level guidance and procedural information uniformly to projects based on interpretations that carry the weight of institutional authority, a process was developed. This paper provides a script for designing processes in general, using this particular process for context. While the context is incidental, the method described is applicable to any process in general. The paper will expound on novel features utilized for dissemination of the procedural details over the Internet following such process design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mohan, SN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,T1710F, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3785 EP 3791 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700376 ER PT S AU Cooper, LP Hecht, MH Majchrzak, A AF Cooper, LP Hecht, MH Majchrzak, A GP IEEE IEEE TI Managing a project's legacy: Implications for organizations and project management SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID RESEARCH-AND-DEVELOPMENT; KNOWLEDGE MANAGEMENT; TECHNOLOGY AB Organizations that rely on projects to implement their products must find effective mechanisms for propagating lessons learned on one project throughout the organization. A broad view of what constitutes a project's "legacy" is presented that includes not just the design products and leftover parts, but new processes, relationships, technology, skills, planning data, and performance metrics. Based on research evaluating knowledge reuse in innovative contexts, this paper presents an approach to project legacy management that focuses on collecting and using legacy knowledge to promote organizational learning and effective reuse, while addressing factors of post-project responsibility, information obsolescence, and the importance of ancillary contextual information. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cooper, LP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3793 EP 3800 PG 8 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700377 ER PT S AU Patterson, FG Haas, SN AF Patterson, FG Haas, SN GP IEEE IEEE TI NASA engineering training: Helping engineers to see better SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This paper describes a fundamental aspect of the NASA Engineering Training (NET) Program and our approach to mitigating a problem that we describe as tunnel vision, the result of overspecialization. Symptoms of this problem include perceived weaknesses in communications, teamwork, and leadership among engineers and engineering teams and organizations. C1 NASA, Washington, DC 20546 USA. RP Patterson, FG (reprint author), NASA, Washington, DC 20546 USA. 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3877 EP 3883 PG 7 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700385 ER PT S AU Atkins, K Gowler, P AF Atkins, K Gowler, P GP IEEE IEEE TI Preparing project managers for high-risk, cost-capped robotic missions SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The Jet Propulsion Laboratory (JPL) has developed and implemented a week-long workshop for Project Managers, designed around the development phases of the JPL Project Life Cycle. The workshop emphasizes the specific activities and deliverables that pertain to JPL managers of NASA robotic space exploration and instrument development projects. The authors are part of a team of professional development, project management, and process personnel that has worked toward building an educational element to support a strong corps of managers for JPL's expanded portfolio of projects. An objective of this paper is to document the efforts of these individuals, over a two-plus-year period, toward ensuring successful management of high-risk, cost-capped missions. The structure and content are responsive to NASA's Program and Project Management Guide (NPG) 7120.5, with a focus on the planning and risk management necessary for strict budget and schedule demands unique to robotic space exploration. Many such projects are driven by planetary flight mechanics, and the slipping of launch periods is generally not acceptable, if even possible. This is decidedly different than management in industries where slipping milestones will result in cost overruns, while the project remains viable. Additionally, costs are "capped" in NASA's competitive selection of these projects, so designing to cost and managing to budget must be more than goal-oriented rhetoric. The work-shop addresses the unique risks and opportunities inherent in unmanned, robotic flight projects, and focuses on specific practices and processes developed by JPL in over 40 years of experience in managing such projects. These processes have been revised and updated for relevance to NASA's Multi-project, cost-capped development paradigm, and include corrective actions taken after in-flight failures of recent missions. Based on JPL's Project Life Cycle, the curriculum structure and learning objectives include transitional gates and reviews, planning, risk management, control, testing, flight operations, project staffing, and transition/archiving. The curriculum content has also been validated against JPL's Flight Project Practices, which are applicable to all JPL-managed flight projects. Readers are encouraged to consider the workshop approach as a benchmark against existing, more-generic management education paradigms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Atkins, K (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-370, 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3915 EP 3926 PG 12 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700389 ER PT S AU Leete, SJ AF Leete, SJ GP IEEE IEEE TI Satellite servicing in mission design studies at the NASA GSFC SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Several NASA missions in various stages of development have undergone one-week studies in the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) Integrated Mission Design Center (IMDC), mostly in preparation for proposals. The possible role of satellite servicing has been investigated for several of these missions, applying the lessons learned from Hubble Space Telescope (HST) servicing, taking into account the current state of the art, projecting into the future, and implementing NASA long-range plans, and is presented here. The general benefits and costs of injecting satellite servicing are detailed, including components such as mission timeline, mass, fuel, spacecraft design, risk abatement, life extension, and improved performance. The approach taken in addressing satellite servicing during IMDC studies is presented. C1 NASA, Goddard Space Flight Ctr, Space Sci Miss Branch, Greenbelt, MD 20771 USA. RP Leete, SJ (reprint author), NASA, Goddard Space Flight Ctr, Space Sci Miss Branch, Code 661, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3957 EP 3966 PG 10 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700393 ER PT S AU Stephens, SK Willenberg, HJ AF Stephens, SK Willenberg, HJ GP IEEE IEEE TI Metrics for in-space telescope assembly techniques SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Reliable metrics are not yet available for choosing among human and robotic assets for space-based construction and servicing of large space telescopes. Using FAIR-DART as a reference design, we generated example event sequences for telescope assembly scenarios in enough detail to identify infrastructure assumptions and technology requirements. A systems trade among human and robotic techniques (human EVA, on-site telerobotic, ground-in-the-loop robotic, commanded or sequenced robotic, and autonomous/decision-making robotic) helped us to define key metrics in the human-robotic trade space, including quality, time, cost, and risk. Our methodology included examining representative end-member scenarios. Case A treated each step in the assembly sequence as if all other steps have no on-site human involvement, and Case B treated each step as if human EVA is already involved in all other steps. With this trade, we identified key enabling technologies and infrastructure for space-based assembly and servicing of large space telescopes. C1 CALTECH, NASA Jet Propuls Lab, Pasadena, CA 91009 USA. RP Stephens, SK (reprint author), CALTECH, NASA Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91009 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3967 EP 3977 PG 11 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700394 ER PT S AU Moe, RV Willenberg, HJ AF Moe, RV Willenberg, HJ GP IEEE IEEE TI In-space, servicing accommodations: Architectural and mission implications SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB The NASA strategic plans consider assembly and servicing of large telescopes and operational servicing facilities in space. Space science, commercial, and military programs will need to assess the utility and impact of servicing and assembly capabilities for their respective facilities. Large or complex in-space facilities may gain significant benefit from minimal investment in human and/or robotic servicing accommodations. More extensive accommodations and processes for repair/maintenance and instrument upgrades can produce increasing returns as benefits to mission productivity and duration. Modem approaches and technology advances to servicing have reduced the burden for serviceability in facility design and increased the productivity of servicer systems. Analyses of facility design impact and mission benefits in serviceability for several degrees of space facility design accommodation are presented. These are assessed against several cases of expected evolution of servicer system capability in the upcoming decades. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moe, RV (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3979 EP 3991 PG 13 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700395 ER PT S AU Moore, CL AF Moore, CL GP IEEE IEEE TI Gossamer space structures panel SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA is developing gossamer space structures for large telescopes, antennas, solar sails, and space solar power systems. These ultra-lightweight structures are constructed from membranes and inflatable and deployable elements that can be packaged compactly for launch. Technical challenges associated with these structures are deployment, rigidization., control of structural dynamics and geometry, ground-based testing, and analytical modeling. An overview of NASA's current research on gossamer space structures will be given in the panel discussion. C1 NASA Headquarters, RP Off Aerosp Technol, Washington, DC 20546 USA. RP Moore, CL (reprint author), NASA Headquarters, RP Off Aerosp Technol, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 2 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 3993 EP 3994 PG 2 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700396 ER PT S AU Montemerlo, M Whittaker, R Moore, C Mika, A AF Montemerlo, M Whittaker, R Moore, C Mika, A GP IEEE IEEE TI Paradigms for successful technology development SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB This panel focuses on technology development programs, not on specific technology tasks. Technology development programs in industry have to satisfy different needs than those in government or in academia. This panel is an attempt to gather together people who manage significant technology development programs in government, academia, and industry and to have them present their ideas on how to build and manage successful technology programs. After presentation of their ideas, we will open up the floor to discussion among the panelists and with the audience. C1 NASA Headquarters, Washington, DC 20546 USA. RP Montemerlo, M (reprint author), NASA Headquarters, 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 4005 EP 4005 PG 1 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700398 ER PT S AU Devirian, NW Marr, J Kahn, P Lindensmith, C Yorke, H AF Devirian, NW Marr, J Kahn, P Lindensmith, C Yorke, H GP IEEE IEEE TI NASA's new roadmap for the astronomical search for orgins SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB NASA first published a roadmap for the Astronomical Search for Origins in 1997. Now, six years and 3 roadmaps later, some lessons have been learned, results have been accomplished, some approaches have been modified, but the vision remains. In 2003, the roadmap has simplified and refined its objectives, and added alternate routes and off-ramps to enhance the manageability of one of NASA's most ambitious science themes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devirian, NW (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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 4007 EP 4008 PG 2 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700399 ER PT S AU Potocki, KA Calabrese, MA Carson, D Ayon, J Robinson, J Oberright, J VanSant, JT AF Potocki, KA Calabrese, MA Carson, D Ayon, J Robinson, J Oberright, J VanSant, JT CA Natl Aeronautics Space Adm GP IEEE IEEE TI NASA's sun-earth connection program strategic planning, missions & technology (2003-2028) SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink AB Our variable star, the Sun, is the source of varying solar wind, electromagnetic fields, and particles that interact with the planets and the galaxy. The Earth's magnetic field and upper atmosphere provide the shielding from the Sun's external influences, and they also form a coupled system with the Sun and the heliosphere. The Sun-Earth Connection (SEC) [1] theme in the NASA Office of Space Science (OSS) has a goal to understand the Sun, heliosphere, and planetary environments as a single connected system. The SEC Roadmap [2] strategy is to develop a synergistic set of missions that will allow us to discover and understand the connected Sun-Earth system in the spatial, temporal, and spectral domain from optimal vantage points in space. These missions will provide the remote and multipoint in situ measurements from unique vantages to support the primary SEC scientific goals and objectives. These missions will image the Sun's atmosphere in three dimensions by including high latitude and polar regions; explore the heliosphere from very near the Sun to the interstellar medium; and determine the connections in the magnetosphere and ionosphere with multisatellite measurements. The first of a series of missions is under way and is being formulated and implemented in two flight programs: the Solar Terrestrial Probes (STP) [3], and the new Living With a Star [LWS] Program [4]. These programs build on the first truly coordinated investigations conducted by the International Solar Terrestrial Physics Program (ISTP) and SEC missions in the 1990s and early 2000s. These earlier missions identified the importance of a system that understands the variable Sun and its interaction with the Earth's geospace. This paper provides an overview of the SEC strategic missions planned for the period 2003-2028 and their technology needs. These missions range from single to multiple spacecraft and even constellations of small satellites. Important technologies include those that enable economical multispacecraft missions, information technology for system-wide measurement and understanding, solar sail propulsion for reduced flight times, and improved scientific instrumentation to provide in situ and imaging observations. Enhancing technology related to systems and instruments are described that can improve payload mass-fraction, performance, and/or lower mission cost. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Potocki, KA (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 0 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 4009 EP 4022 PG 14 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700400 ER PT S AU De Minco, P Schwartz, PC AF De Minco, P Schwartz, PC GP IEEE IEEE TI Technology for structure and evolution of the universe SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP De Minco, P (reprint author), NASA, Goddard Space Flight Ctr, Mailstop 101-0, Greenbelt, MD 20771 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 SN 1095-323X BN 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 4023 EP 4023 PG 1 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700401 ER PT S AU Haberle, RM AF Haberle, RM CA Pascal Sci Team GP IEEE IEEE TI The science return of the Pascal Mars Scout mission SO 2003 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-8 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 08-15, 2003 CL BIG SKY, MT SP IEEE Aerosp & Elect Syst Soc, Aerosp Corp, Analog Interfaces, AstroExpo com, Caltech, JPL, Circle Mt Co, Gandalf Associates, LLC, GEB Software Technologies, Missile Defense Agcy, NASA, Panasonic, SpectrumAstro, Superior Solut, TechLink ID GENERAL-CIRCULATION MODEL; GLOBAL DUST STORMS; THERMAL EMISSION SPECTROMETER; MARTIAN ATMOSPHERE; SURFACE PRESSURE; INTERANNUAL VARIABILITY; OBSERVATIONAL EVIDENCE; NUMERICAL SIMULATIONS; TIDES; WATER AB Pascal is a Mars Scout mission that will establish a global network of 18 weather stations on the surface of Mars that will take daily measurements of pressure, opacity, temperature, wind speed, and water vapor concentration for at least 3 Mars years (5.5 Earth years). Each station will also acquire monthly panoramic images to monitor changes in surface features due to aeolian processes. These data will define the dust, water, and CO2 cycles, and characterize the nature of the near-surface general circulation and how it interacts with the surface. C1 NASA, Ames Res Ctr, Space Sci Div, Pascal Sci Team, Moffett Field, CA 94035 USA. RP Haberle, RM (reprint author), NASA, Ames Res Ctr, Space Sci Div, Pascal Sci Team, MS 245-3, Moffett Field, CA 94035 USA. NR 71 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 0-7803-7651-X J9 AEROSP CONF PROC PY 2003 BP 4025 EP 4039 PG 15 WC Engineering, Aerospace SC Engineering GA BX65K UT WOS:000185997700402 ER PT B AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS GP IEEE IEEE IEEE TI Average bit error probability performance for optimum diversity combining of noncoherent FSK over Rayleigh fading channels SO 2003 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-5: NEW FRONTIERS IN TELECOMMUNICATIONS LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC) CY MAY 11-15, 2003 CL ANCHORAGE, AK SP IEEE Commun Soc, AT&T Alascom, Hotel Captain Cook, GCI, New Horizons, PanAmSat, SES Americom, Tellabs, Univ Alaska Anchorage AB We derive the performance of the optimum noncoherent FSK diversity combining receiver and compare it with that which implements the more traditional noncoherent postdetection EGC scheme to reveal the degree of suboptimality of the latter. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (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 BN 0-7803-7802-4 PY 2003 BP 2768 EP 2772 PG 5 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics; Telecommunications SC Computer Science; Engineering; Optics; Telecommunications GA BW96Y UT WOS:000183802400532 ER PT B AU Simon, MK AF Simon, MK GP IEEE IEEE IEEE TI Multiple bit differential detection of offset quadrature phase-shift-keying SO 2003 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-5: NEW FRONTIERS IN TELECOMMUNICATIONS LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC) CY MAY 11-15, 2003 CL ANCHORAGE, AK SP IEEE Commun Soc, AT&T Alascom, Hotel Captain Cook, GCI, New Horizons, PanAmSat, SES Americom, Tellabs, Univ Alaska Anchorage AB Analogous to multiple symbol differential detection of quadrature phase-shift-keying (QPSK), a multiple bit differential detection scheme is described for offset QPSK that also exhibits continuous improvement in performance with increasing observation interval. Being derived from maximum-likelihood (ML) considerations, the proposed scheme is purported to be the most power efficient scheme for such a modulation and detection method. Extension of the results to shaped offset QPSK is also possible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (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 0-7803-7802-4 PY 2003 BP 2817 EP 2821 PG 5 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics; Telecommunications SC Computer Science; Engineering; Optics; Telecommunications GA BW96Y UT WOS:000183802400541 ER PT B AU Ye, Z Satorius, EH AF Ye, Z Satorius, EH GP IEEE IEEE IEEE TI Channel modeling and simulation for Mobile User Objective System (MUOS) - Part 1: Flat scintillation and fading SO 2003 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-5: NEW FRONTIERS IN TELECOMMUNICATIONS LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC) CY MAY 11-15, 2003 CL ANCHORAGE, AK SP IEEE Commun Soc, AT&T Alascom, Hotel Captain Cook, GCI, New Horizons, PanAmSat, SES Americom, Tellabs, Univ Alaska Anchorage AB Performance of the Mobile User Objective System is dominated by the channel conditions characterized by ionospheric scintillation and multipath fading. Detail analytical channel modeling is provided, with the emphasis on narrowband waveforms in Part I of this paper. Efficient computer simulation techniques for these flat fading channel impairment have also been presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ye, Z (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 0-7803-7802-4 PY 2003 BP 3503 EP 3510 PG 8 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics; Telecommunications SC Computer Science; Engineering; Optics; Telecommunications GA BW96Y UT WOS:000183802400677 ER PT B AU Satorius, EH Ye, Z Kullstam, PA AF Satorius, EH Ye, Z Kullstam, PA GP IEEE IEEE IEEE TI Channel modeling and simulation for Mobile User Objective System (MUOS) -- Part II: Selective scintillation and terrestrial multipath fading SO 2003 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-5: NEW FRONTIERS IN TELECOMMUNICATIONS LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC) CY MAY 11-15, 2003 CL ANCHORAGE, AK SP IEEE Commun Soc, AT&T Alascom, Hotel Captain Cook, GCI, New Horizons, PanAmSat, SES Americom, Tellabs, Univ Alaska Anchorage AB Performance of the Mobile User Objective System is dominated by the channel conditions characterized by ionospheric scintillation and multipath fading. Detail analytical modeling for flat channel is provided in Part I of this paper, while the emphasis of Part II of this paper is on wideband waveforms. Efficient computer simulation techniques for the selective scintillation and terrestrial multipath fading channel impairment have been presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Satorius, EH (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 0-7803-7802-4 PY 2003 BP 3511 EP 3518 PG 8 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics; Telecommunications SC Computer Science; Engineering; Optics; Telecommunications GA BW96Y UT WOS:000183802400678 ER PT B AU Hu, YX Cai, Y Tomzak, M Lee, T AF Hu, YX Cai, Y Tomzak, M Lee, T GP IEEE TI Multisensor inversion with high-performance FPGA computation SO 2003 IEEE INTERNATIONAL CONFERENCE ON FIELD-PROGRAMMABLE TECHNOLOGY (FPT), PROCEEDINGS LA English DT Proceedings Paper CT 2nd International Conference on Field-Programmable Technology (ICFPT 2003) CY DEC 15-17, 2003 CL Univ Tokyo, Tokyo, JAPAN SP Univ Tokyo, VLSI Design & Educ Ctr, IEEE Elect Devices Soc, IEEE Japan Council, Xillinx Inc, Celoxica, Interdesign Technol, Tokyo Elect Device Ltd, Memec Japan K K, Elixent Inc, Synplic Inc, Altera Corp, Quicksilver HO Univ Tokyo AB An FPGA-based reconfigurable generalized inversion processor is developed for real-time physical property retrievals of the atmosphere, land and ocean. The processor is based on Generalized Non-Linear Regression algorithm and trained with radiative transfer simulations and observations for autonomous detection of satellite measurement signatures and retrievals of atmospheric physical properties. The FPGA approach is faster than traditional computing methods in orders of magnitude. The generalized inversion processor is able to automatically adapt to multi-platform sensors, eliminate redundant algorithm development and provide a vehicle for autonomous onboard image analysis and physics-based data compressions. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Hu, YX (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. RI Hu, Yongxiang/K-4426-2012 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 0-7803-8320-6 PY 2003 BP 439 EP 442 DI 10.1109/FPT.2003.1275797 PG 4 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Imaging Science & Photographic Technology SC Computer Science; Imaging Science & Photographic Technology GA BY90N UT WOS:000189491800073 ER PT S AU Castano, A Matthies, L AF Castano, A Matthies, L GP IEEE IEEE TI Foliage discrimination using a rotating ladar SO 2003 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-3, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 20th IEEE International Conference on Robotics and Automation (ICRA) CY SEP 14-19, 2003 CL TAIPEI, TAIWAN SP IEEE Robot & Automat Soc, Natl Sci Council, Minist Educ, Chinese Inst Automat Engineers, Ind Technol Res Inst, TECO Elect & Machinery Co Ltd, Met Ind Res & Dev Ctr AB An outdoor environment presents to a robot objects that are drivable, such as tall grass and small bushes, and non-drivable, such as trees and rocks. Due to the difficulty of discriminating between these classes, traditionally a robot searches for paths free of any objects, drivable or not. Although this approach prevents collisions with objects misclassified as drivable, it also eliminates a large number of drivable paths and by doing so, it may eliminate the only path to a desired destination. We present a real time algorithm that detects foliage using range from a rotating ladar. Objects not classified as foliage are conservatively labeled as nondrivable obstacles. In contrast to related work that uses range statistics to classify the objects, we exploit the expected localities and continuities of an obstacle, in both space and time. Also, instead of attempting to find a single accurate discriminating factor for every ladar return, we hypothesize the class of some few returns and then spread the confidence (and classification) to other returns using the locality constraints. The Urbie robot is presently using this algorithm to discriminate drivable grass from obstacles during outdoor autonomous navigation tasks. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Castano, A (reprint author), Jet Prop Lab, 4800 Oak Grove Dr,MS 125-209, Pasadena, CA 91109 USA. NR 8 TC 13 Z9 13 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-7736-2 J9 IEEE INT CONF ROBOT PY 2003 BP 1 EP 6 PG 6 WC Robotics SC Robotics GA BY05H UT WOS:000187419900001 ER PT S AU Howard, A Werger, B Seraji, H AF Howard, A Werger, B Seraji, H GP IEEE IEEE TI Integrating terrain maps into a reactive navigation strategy SO 2003 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-3, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 20th IEEE International Conference on Robotics and Automation (ICRA) CY SEP 14-19, 2003 CL TAIPEI, TAIWAN SP IEEE Robot & Automat Soc, Natl Sci Council, Minist Educ, Chinese Inst Automat Engineers, Ind Technol Res Inst, TECO Elect & Machinery Co Ltd, Met Ind Res & Dev Ctr AB This paper presents a new method for integrating terrain maps into a reactive navigation strategy of field mobile robots operating on rough terrain. The method incorporates the Regional Traversability Map, a fuzzy map representation of traversal difficulty of the regional terrain, into the navigation logic. A map-based regional navigation behavior provides speed and direction recommendations based on the current status Of the robot. In addition, recommendations from two sensor-based reactive behaviors, local avoid-obstacle and regional traverse-terrain, are fused with the map-based regional behavior to construct a comprehensive navigation system. The algorithms are tested both in graphical simulations and in the field using a commercial Pioneer 2AT robot to demonstrate traversal over rough natural terrain. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Howard, A (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-7736-2 J9 IEEE INT CONF ROBOT PY 2003 BP 2012 EP 2017 DI 10.1109/ROBOT.2003.1241889 PG 6 WC Robotics SC Robotics GA BY05H UT WOS:000187419900322 ER PT S AU Pedersen, L Bualat, M Kunz, C Lee, S Sargent, R Washington, R Wright, A AF Pedersen, L Bualat, M Kunz, C Lee, S Sargent, R Washington, R Wright, A GP IEEE IEEE TI Instrument deployment for mars rovers SO 2003 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-3, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT 20th IEEE International Conference on Robotics and Automation (ICRA) CY SEP 14-19, 2003 CL TAIPEI, TAIWAN SP IEEE Robot & Automat Soc, Natl Sci Council, Minist Educ, Chinese Inst Automat Engineers, Ind Technol Res Inst, TECO Elect & Machinery Co Ltd, Met Ind Res & Dev Ctr AB Future Mars rovers, such as the planned 2009 MSL rover, require sufficient autonomy to robustly approach rock targets and place an instrument in contact with them. It took the 1997 Sojourner Mars rover between 3 and 5 communications cycles to accomplish this. This paper describes the NASA Ames approach to robustly accomplishing single cycle instrument deployment, using the K9 prototype Mars rover. An off-board 3D site model is used to select science targets for the rover. K9 navigates to targets, using deduced reckoning, and autonomously assesses the target area to determine where to place an arm mounted microscopic camera. Onboard K9 is a resource cognizant conditional executive, which extends the complexity and duration of operations that a can be accomplished without intervention from mission control. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pedersen, L (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 1 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-7736-2 J9 IEEE INT CONF ROBOT PY 2003 BP 2535 EP 2542 DI 10.1109/ROBOT.2003.1241974 PG 8 WC Robotics SC Robotics GA BY05H UT WOS:000187419900407 ER PT B AU Shao, X Goldsman, N Ramahi, O Guzdar, PN AF Shao, X Goldsman, N Ramahi, O Guzdar, PN GP IEEE IEEE TI A new method for simulation of on-chip interconnects and substrate currents with 3D alternating-direction-implicit (ADI) Maxwell solver SO 2003 IEEE INTERNATIONAL CONFERENCE ON SIMULATION OF SEMICONDUCTOR PROCESSES AND DEVICES LA English DT Proceedings Paper CT IEEE International Conference on Simulation of Semiconductor Processes and Devices CY SEP 03-05, 2003 CL BOSTON, MA SP IEEE Elect Devices Soc ID EQUATIONS; ALGORITHM AB We introduce a time-domain method to simulate the digital signal propagation along on-chip interconnects by solving Maxwell's equations with the Alternating-Direction-Implicit (ADI) method. With this method, we are able to resolve the large scale (i.e. on-chip electromagnetic wave propagation) and fine scale (i.e. skin depth and substrate current) structure in the same simulation, and the simulation time step is not limited by the Courant condition. The simulations allow us to calculate in detail parasitic current flow inside the substrate; propagation losses; skin-depth; and dispersion of digital signals on non-ideal interconnects. We have found considerable substrate currents and losses that depend on the substrate doping. C1 NASA, Goddard Space Flight Ctr, Space Phys Data Facil, Greenbelt, MD 20171 USA. RP Shao, X (reprint author), NASA, Goddard Space Flight Ctr, Space Phys Data Facil, Greenbelt, MD 20171 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 BN 0-7803-7826-1 PY 2003 BP 315 EP 318 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Condensed Matter SC Engineering; Instruments & Instrumentation; Physics GA BX55G UT WOS:000185660800078 ER PT S AU Ravinder, U Hayes, C AF Ravinder, U Hayes, C GP IEEE IEEE TI Weasel: An automated planner that users can guide SO 2003 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN AND CYBERNETICS, VOLS 1-5, CONFERENCE PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man and Cybernetics (SMC 03) CY OCT 05-08, 2003 CL WASHINGTON, D.C. SP IEEE, Syst, Man & Cybernet Soc AB A difficulty for military analysts is to thoroughly consider possible plans which the enemy might follow under various assumptions. However, it is critical to do so to avoid dangerous surprises. Weasel is a decision support system that assists intelligence analysts in developing alternative enemy courses of action (ECOAs) consistent with intelligence conclusions and specified assumptions. A design goal behind Weasel is to provide users with the convenience of automation while still providing them with flexibility and control over the results. Weasel allows users to perform "what if" analyses in which they can change assumptions about enemy resources, current position, and maneuver constraints. Weasel integrates two other decision support tools, CoRaven, which assists in analyzing intelligence data, and Fox, which assists in generating friendly courses of action (FCOAs). The combination of CoRaven, Weasel and Fox can provide powerful assistance in the military tactical decision making process. C1 NASA, Moffett Field, CA 94035 USA. RP Ravinder, U (reprint author), NASA, Moffett Field, CA 94035 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 1062-922X BN 0-7803-7952-7 J9 IEEE SYS MAN CYBERN PY 2003 BP 953 EP 955 PG 3 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BX83D UT WOS:000186578600155 ER PT S AU Rajkumar, T Bardina, JE AF Rajkumar, T Bardina, JE GP IEEE IEEE TI Web-based Weather Expert System (WES) for Space Shuttle Launch SO 2003 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN AND CYBERNETICS, VOLS 1-5, CONFERENCE PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man and Cybernetics (SMC 03) CY OCT 05-08, 2003 CL WASHINGTON, D.C. SP IEEE, Syst, Man & Cybernet Soc DE weather tracking; expert system; shuttle launch and range operations AB The Web-based Weather Expert System (WES) is a critical module of the Virtual Test Bed development to support "go/no go"' decisions for Space Shuttle operations in the Intelligent Launch and Range Operations program of NASA. The weather rules characterize certain aspects of the environment related to the launching or landing site, the time of the day or night, the pad or runway conditions, the mission durations, the runway equipment and landing type. Expert system rules are derived from weather contingency rules, which were developed over several years by NASA. Backward chaining, a goal-directed inference method is adopted, because a particular consequence or goal clause is evaluated first, and then chained backward through the rules. Once a rule is satisfied or true, then that particular rule is fired and the decision is expressed. The expert system is continuously verifying the rules against the past one-hour weather conditions and the decisions are made. The normal procedure of operations requires a formal pre-launch weather briefing held on Launch minus 1 day, which is a specific weather briefing for all areas of Space Shuttle launch operations. In this paper, the Web-based Weather Expert System of the Intelligent Launch and range Operations program is presented. C1 NASA, Ames Res Ctr, SAIC, Moffett Field, CA 94035 USA. RP Rajkumar, T (reprint author), NASA, Ames Res Ctr, SAIC, MS 269-2, Moffett Field, CA 94035 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 1062-922X BN 0-7803-7952-7 J9 IEEE SYS MAN CYBERN PY 2003 BP 5040 EP 5045 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BX83D UT WOS:000186578600821 ER PT B AU Chen, Y Nguyen, D Guertin, S Bernstein, J White, M Menke, R Kayali, S AF Chen, Y Nguyen, D Guertin, S Bernstein, J White, M Menke, R Kayali, S GP IEEE TI A reliability evaluation methodology for memory chips for space applications when sample size is small SO 2003 IEEE INTERNATIONAL INTEGRATED RELIABILITY WORKSHOP - FINAL REPORT LA English DT Proceedings Paper CT IEEE International Integrated Reliability Workshop CY OCT 20-23, 2003 CL Lake Tahoe, CA SP IEEE Electron Devices Soc, IEEE Reliabil Soc AB This paper presents a reliability evaluation methodology to obtain the statistical reliability information of memory chips for space applications when the test sample size needs to be kept small because of the high cost of the radiation hardness memories. This methodology can be also used to generate overdriving guidelines and characterize production lines in commercial applications and to obtain de-rating guidelines in space applications. C1 CALTECH, Jet Prop Lab, Elect Parts Engn Off, Pasadena, CA 91109 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, Elect Parts Engn Off, 4800 Oak Grove Dr,Mail Stop 303-230, 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 BN 0-7803-8157-2 PY 2003 BP 91 EP 94 PG 4 WC Engineering, Electrical & Electronic; Physics, Condensed Matter SC Engineering; Physics GA BY66Z UT WOS:000189434800019 ER PT B AU White, M Cooper, M Chen, Y Bernstein, J AF White, M Cooper, M Chen, Y Bernstein, J GP IEEE TI Impact of junction temperature on microelectronic device reliability and considerations for space applications SO 2003 IEEE INTERNATIONAL INTEGRATED RELIABILITY WORKSHOP - FINAL REPORT LA English DT Proceedings Paper CT IEEE International Integrated Reliability Workshop CY OCT 20-23, 2003 CL Lake Tahoe, CA SP IEEE Electron Devices Soc, IEEE Reliabil Soc AB The space community and other high reliability users of microelectronic devices have been derating junction temperature and other critical stress parameters for decades to improve device reliability and extend operating life. Semiconductor technology scaling and process improvements, however, compel us to reassess common failure mechanisms and established derating guidelines to provide affirmation that common derating factors remain adequate for current technologies used in high reliability space applications. It is incumbent upon the user to develop an understanding of advanced technology failure mechanisms through modeling, accelerated testing, and failure analysis prior to product insertion in critical applications. This paper provides a summary of an industry survey on junction temperature derating from key microelectronics suppliers, and offers recommendations to users for temperature derating for reliable operation over time. Background information on established derating factors, and recommendations for safe operating junction temperatures for newer technologies are also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP White, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 303-230, 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 0-7803-8157-2 PY 2003 BP 133 EP 136 PG 4 WC Engineering, Electrical & Electronic; Physics, Condensed Matter SC Engineering; Physics GA BY66Z UT WOS:000189434800032 ER PT B AU Zheng, XY Seshadri, S Wood, M Wrigley, C Pain, B AF Zheng, XY Seshadri, S Wood, M Wrigley, C Pain, B GP IEEE IEEE TI New process and pixel structure of an SOI-CMOS imager SO 2003 IEEE INTERNATIONAL SOI CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International SOI Conference CY SEP 29-OCT 02, 2003 CL NEWPORT BEACH, CA SP IEEE Elect Devices Soc AB We present architecture, process design and results from test pixels of a new Active Pixel Sensor (APS) imager implemented in 0.8 mum SOI-CMOS technology. The conventional partially-depleted SOI-CMOS process has been altered by adding one lithography for buried oxide window opening and two implants into the handle wafer. Results on front illuminated photodiode arrays show that the Quantum Efficiency (QE) are 2-10x improved in peak and red spectral response, respectively, compared to bulk APS imagers. Dark current tests on photodiodes and pixels indicate a periphery-dominated and voltage-dependent leakage current of 5-20 nA/cm(2) at 3V. Pixel linearity error of similar to4% is observed at 80% of saturation. Test results indicate directions for further reduction of the dark current. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zheng, XY (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 0-7803-7815-6 PY 2003 BP 101 EP 102 DI 10.1109/SOI.2003.1242915 PG 2 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BX71S UT WOS:000186203600040 ER PT B AU Moision, B Hamkins, J AF Moision, B Hamkins, J GP IEEE IEEE TI Low-complexity serially-concatenated coding for the deep space optical channel SO 2003 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY - PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 29-JUL 04, 2003 CL Yokohama, JAPAN SP IEEE, IEEE Informat Theory Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Moision, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 0-7803-7728-1 PY 2003 BP 100 EP 100 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BX68L UT WOS:000186112600100 ER PT B AU Dolinar, S AF Dolinar, S GP IEEE IEEE TI Design and iterative decoding of networks of many small codes SO 2003 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY - PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 29-JUL 04, 2003 CL Yokohama, JAPAN SP IEEE, IEEE Informat Theory Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dolinar, S (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 0-7803-7728-1 PY 2003 BP 346 EP 346 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BX68L UT WOS:000186112600346 ER PT B AU Hamkins, J Divsalar, D AF Hamkins, J Divsalar, D GP IEEE IEEE TI Coupled receiver-decoders for low rate turbo codes SO 2003 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY - PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 29-JUL 04, 2003 CL Yokohama, JAPAN SP IEEE, IEEE Informat Theory Soc AB We present a rate 1/31 turbo code that achieves a bit error rate of 10(-6) at E-b/N-0 = -0.9 dB. At this coding gain, insufficient energy per symbol is present for a conventional receiver to recover the carrier phase properly. We present a method to overcome this problem by coupling the receiver and decoder functions. Simulations indicate that this approach may enable the elimination or significant reduction of required residual carrier power for signaling on AWGN channels impaired by phase noise. C1 CALTECH, Jet Prop Lab, Commun Syst & Res Sect, Pasadena, CA 91109 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, Commun Syst & Res Sect, 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 BN 0-7803-7728-1 PY 2003 BP 381 EP 381 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BX68L UT WOS:000186112600381 ER PT S AU Hemmati, H AF Hemmati, H GP IEEE IEEE TI Optical space communications at JPL SO 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society CY OCT 27-30, 2003 CL TUCSON, AZ SP IEEE Lasers & Electro Opt Soc AB Subsystem and system level technology development at JPL for free-space laser communications from both deep space and near-Earth is described. These include acquisition, tracking and pointing, laser transmitters, photon-counting receivers, coding, modulation, and communication systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hemmati, H (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 SN 1092-8081 BN 0-7803-7888-1 J9 IEEE LEOS ANN MTG PY 2003 BP 81 EP 82 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BY23D UT WOS:000188359700040 ER PT S AU Ortiz, GG Lee, S AF Ortiz, GG Lee, S GP IEEE IEEE TI Acquisition, tracking, and pointing using earth thermal images for deep space optical communications SO 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society CY OCT 27-30, 2003 CL TUCSON, AZ SP IEEE Lasers & Electro Opt Soc AB The feasibility of using long wavelength Earth thermal (infrared) images for telescope tracking/pointing applications for both Deep Space Free-Space Optical Communications has been investigated and is reported-here. The advantage of this technology rests on using full Earth images in this band, which yield more accurate estimates of geometric centroids than that of Earth images in the visible band. Another Major advantage is that these images are nearly independent of Earth phase angle. The results of the study show that at a Mars range, with currently available sensors, a noise equivalent angle of 10 to 150 nanoradians and a bias error of better than 80 nanoradians can be obtained. This enables precise pointing of the optical communications beam for high data rate links. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ortiz, GG (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 SN 1092-8081 BN 0-7803-7888-1 J9 IEEE LEOS ANN MTG PY 2003 BP 83 EP 84 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BY23D UT WOS:000188359700041 ER PT S AU Lee, S Ortiz, GG AF Lee, S Ortiz, GG GP IEEE IEEE TI Inertial sensor assisted acquisition, tracking, and pointing for high. data rate free space optical communications SO 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society CY OCT 27-30, 2003 CL TUCSON, AZ SP IEEE Lasers & Electro Opt Soc AB We discuss use of inertial sensors to facilitate deep space optical communications. Implementation of this concept requires accurate and wide bandwidth inertial sensors. In this presentation, the principal concept and algorithm using linear accelerometers will be given along with the simulation and experimental results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 SN 1092-8081 BN 0-7803-7888-1 J9 IEEE LEOS ANN MTG PY 2003 BP 87 EP 88 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BY23D UT WOS:000188359700043 ER PT S AU Yang, RQ Hill, CJ Yang, B AF Yang, RQ Hill, CJ Yang, B GP IEEE IEEE TI Thin top-cladding interband cascade lasers operating at room temperature SO 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society CY OCT 27-30, 2003 CL TUCSON, AZ SP IEEE Lasers & Electro Opt Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Yang, RQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 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 1092-8081 BN 0-7803-7888-1 J9 IEEE LEOS ANN MTG PY 2003 BP 346 EP 347 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BY23D UT WOS:000188359700175 ER PT S AU Barnes, NP AF Barnes, NP GP IEEE IEEE TI Role of nonlinear optics in NASA remote sensing program SO 2003 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 16th Annual Meeting of the IEEE Lasers and Electro-Optics Society CY OCT 27-30, 2003 CL TUCSON, AZ SP IEEE Lasers & Electro Opt Soc C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Barnes, NP (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 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 SN 1092-8081 BN 0-7803-7888-1 J9 IEEE LEOS ANN MTG PY 2003 BP 937 EP 938 PG 2 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BY23D UT WOS:000188359700471 ER PT S AU Ponchak, GE AF Ponchak, GE BE Thal, H TI Experimental analysis of reduced-sized coplanar waveguide transmission lines SO 2003 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY JUN 08-13, 2003 CL PHILADELPHIA, PA SP IEEE MTT S ID PHASE SHIFTERS; DESIGN AB An experimental investigation of the use of capacitive loading of coplanar waveguides to reduce their line length and, thus the size, of monolithic microwave integrated circuits is presented. The reduced sized coplanar waveguides are compared to unloaded transmission lines and to lumped element transmission line segments. The phase bandwidth, defined by 2 percent error in S-21, and the return loss bandwidth, defined by a return loss greater than 15 dB, of coplanar waveguides reduced from 0 to 90 percent are compared, and the insertion loss as a function of the size reduction is presented. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. NR 10 TC 4 Z9 4 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-645X BN 0-7803-7695-1 J9 IEEE MTT-S PY 2003 BP 971 EP 974 DI 10.1109/MWSYM.2003.1212531 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BX04J UT WOS:000184045100278 ER PT S AU Dawson, D Gaier, T Raja, R Nishimoto, M Lai, R Wells, M AF Dawson, D Gaier, T Raja, R Nishimoto, M Lai, R Wells, M BE Thal, H TI Cryogenic measurements of 183 GHz MMIC low noise amplifiers SO 2003 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY JUN 08-13, 2003 CL PHILADELPHIA, PA SP IEEE MTT S ID TRANSITIONS AB We report the packaging and first measurement of Indium Phosphide (InP) monolithic microwave integrated circuit (MMIC) low noise amplifiers (LNAs) operating at cryogenic temperatures above 140 GHz. The amplifiers were measured from 160 to 188 GHz at 20K and tested for noise temperature and gain, with noise temperatures of 160K. The packaging method and test setup will be described, as well as the detailed results at room and cryogenic temperatures. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dawson, D (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 0149-645X BN 0-7803-7695-1 J9 IEEE MTT-S PY 2003 BP 1585 EP 1587 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BX04J UT WOS:000184045100423 ER PT S AU Gaier, T Dawson, D Wells, M AF Gaier, T Dawson, D Wells, M BE Thal, H TI A broadband 100 GHz phase switch/mixer using a uniplanar slotline transition SO 2003 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST, VOLS 1-3 SE IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM DIGEST LA English DT Proceedings Paper CT IEEE MTT-S International Microwave Symposium CY JUN 08-13, 2003 CL PHILADELPHIA, PA SP IEEE MTT S AB We have developed a broadband 180degrees phase switch using one-sided planar grounded slotline design. The design is based upon a grounded coplanar waveguide (CPW) to slotline transition acting as a balun. This design offers several advantages over existing topologies making it well suited to monolithic microwave integrated circuit (MMIC) integration. The uniplanar construction allows for simple module integration and the slot transition with a cutoff frequency serves the same function as a waveguide transition used in multipliers and mixers. We fabricated a switch using flip-chip Schottky diodes and demonstrated the circuit as a W-band phase switch and a mixer. The switch has 5 dB insertion loss and phase flatness 10degrees from 90-110 GHz. As a mixer the circuit performs with 12 dB conversion loss from 76-112 GHz, with an IF bandwidth exceeding 25 GHz. This performance is comparable to commercially available waveguide mixers, which are incompatible with MMIC integration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gaier, T (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 0149-645X BN 0-7803-7695-1 J9 IEEE MTT-S PY 2003 BP 2245 EP 2248 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BX04J UT WOS:000184045100579 ER PT B AU McClure, SS Gorelick, JL Yui, CC Rax, BG Wiedeman, MD AF McClure, SS Gorelick, JL Yui, CC Rax, BG Wiedeman, MD GP IEEE TI Continuing evaluation of bipolar linear devices for total dose bias dependency and ELDRS effects SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc ID RADIATION AB We present results of continuing efforts to evaluate total dose bias dependency and ELDRS effects in bipolar linear microcircuits. Several devices were evaluated, each exhibiting moderate to significant bias and/or dose rate dependency. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McClure, SS (reprint author), Northrop Grumman Space Technol, Redondo Beach, CA 90278 USA. NR 11 TC 4 Z9 7 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8127-0 PY 2003 BP 1 EP 5 DI 10.1109/REDW.2003.1281310 PG 5 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100001 ER PT B AU Nguyen, DN Scheick, LZ AF Nguyen, DN Scheick, LZ GP IEEE TI TID, SEE and radiation induced failures in advanced flash memories SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc AB We report on TID and SEE tests of multi-level and higher density flash memories. Stand-by currents and functionality tests were used to characterize the response of radiation-induced failures. The radiation-induced failures can be categorized as followings: SEU read errors during irradiation, stuck-bit read errors verified post-irradiation, write errors, erase failures, multiple upsets, and single-event latch up. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nguyen, DN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 1 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8127-0 PY 2003 BP 18 EP 23 DI 10.1109/REDW.2003.1281316 PG 6 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100004 ER PT B AU Pritchard, BE Rax, BG McClure, SS AF Pritchard, BE Rax, BG McClure, SS GP IEEE TI Recent radiation test results at JPL SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc DE total ionizing dose; ELDRS; proton damage; displacement damage AB This paper documents recent TID (including ELDRS) and proton damage test results obtained by JPL. Unusual test results, such as abnormally low or high failure levels or unusual failure or response mechanisms, are emphasized. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pritchard, BE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8127-0 PY 2003 BP 24 EP 33 DI 10.1109/REDW.2003.1281317 PG 10 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100005 ER PT B AU Coss, JR AF Coss, JR GP IEEE TI Update of integrated circuit SEE responses: 2001-2002 SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc DE single-event upset; latchup; functional interrupt; SEU; SEL; SEFI ID HEAVY-IONS; SUSCEPTIBILITY; TRENDS AB This tenth biennial update presents heavy ion and proton SEE data from various test groups over the past two years. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Coss, JR (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 27 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8127-0 PY 2003 BP 43 EP 56 DI 10.1109/REDW.2003.1281343 PG 14 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100008 ER PT B AU O'Bryan, MV LaBel, KA Howard, JW Poivey, C Ladbury, RL Kniffin, SD Buchner, SP Xapsos, M Reed, RA Sanders, AB Seidleck, CM Marshall, CJ Marshall, PW Titus, J McMorrow, D Li, K Gambles, J Stone, RF Patterson, JD Kim, HS Hawkins, DK Carts, MA Forney, JD Irwin, T Kahric, Z Cox, SR Palor, C AF O'Bryan, MV LaBel, KA Howard, JW Poivey, C Ladbury, RL Kniffin, SD Buchner, SP Xapsos, M Reed, RA Sanders, AB Seidleck, CM Marshall, CJ Marshall, PW Titus, J McMorrow, D Li, K Gambles, J Stone, RF Patterson, JD Kim, HS Hawkins, DK Carts, MA Forney, JD Irwin, T Kahric, Z Cox, SR Palor, C GP IEEE TI Single event effects results for candidate spacecraft electronics for NASA SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc ID PULSED-LASER; SETS AB We present data on the vulnerability of a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects. Devices tested include digital, analog, linear bipolar, and hybrid devices, among others. C1 NASA, Goddard Space Flight Ctr, Raytheon Informat Technol & Sci Serv, Greenbelt, MD 20771 USA. RP O'Bryan, MV (reprint author), NASA, Goddard Space Flight Ctr, Raytheon Informat Technol & Sci Serv, Code 561-4,Bldg 22,Rm 062A, Greenbelt, MD 20771 USA. NR 44 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8127-0 PY 2003 BP 65 EP 76 DI 10.1109/REDW.2003.1281346 PG 12 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100010 ER PT B AU Shojah-Ardalan, S Wilkins, R Machado, HU Syed, BA McClure, S Rax, B Scheick, L Weideman, M Yui, C Reed, M Ahmed, Z AF Shojah-Ardalan, S Wilkins, R Machado, HU Syed, BA McClure, S Rax, B Scheick, L Weideman, M Yui, C Reed, M Ahmed, Z GP IEEE TI Susceptibility of "ultracapacitors" to proton and gamma irradiation SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc AB Ultracapacitors are promising components for energy storage, power backup and delivery systems. Our study examines the possible effects associated with gamma and proton irradiation in selected samples up to 1200 Farad. C1 NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shojah-Ardalan, S (reprint author), NASA, Jet Prop Lab, 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 BN 0-7803-8127-0 PY 2003 BP 89 EP 91 DI 10.1109/REDW.2003.1281351 PG 3 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100013 ER PT B AU Yui, CC Swift, GM Carmichael, C Koga, R George, JS AF Yui, CC Swift, GM Carmichael, C Koga, R George, JS GP IEEE TI SEU mitigation testing of xilinx virtex IIFPGAs SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc AB SRAM-based reconfigurable programmable logic is widely used in commercial applications and occasionally used in space flight applications because of its susceptibility to single-event upset (SEU). Upset detection and mitigation schemes have been tested on the Xilinx Virtex II X-2V1000 in heavy-ion and proton irradiation to control the accumulation of SEUs and to mitigate their effects on the intended operation. Non-intrusive upset detection and partial reconfiguration in combination with TMR can repair the design to maintain state information. In-beam results on a simple test design demonstrate the effectiveness of these methods when used together. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yui, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. 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 BN 0-7803-8127-0 PY 2003 BP 92 EP 97 DI 10.1109/REDW.2003.1281354 PG 6 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100014 ER PT B AU Selva, LE Scheick, LZ McClure, S Miyahira, T Guertin, SM Shah, SK Edmonds, LD Patterson, JD AF Selva, LE Scheick, LZ McClure, S Miyahira, T Guertin, SM Shah, SK Edmonds, LD Patterson, JD GP IEEE TI Catastrophic SEE in high-voltage power MOSFETs SO 2003 IEEE RADIATION EFFECTS DATA WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop held in Conjunction with IEEE Nuclear and Space Radiation Effects Conference CY JUL 21-25, 2003 CL MONTEREY, CA SP IEEE Nucl & Plasma Sci Soc, Inst Elect & Elect Engineers Inc AB Heavy ion irradiation of high-voltage power MOSFETs with long-range ions (>123mum in silicon) was performed using 14, 19, 22, 24, 28, and 39 MeV-cm(2)/mg ions at normal incidence. Prior to catastrophic failure some DUTs exhibited unusual electrical characteristic: all devices demonstrated high current transients (or current spikes) at voltages significantly lower than the voltage at which the devices failed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Selva, LE (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 0-7803-8127-0 PY 2003 BP 113 EP 120 PG 8 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Computer Science; Physics GA BY48Z UT WOS:000189348100018 ER PT B AU Harris, PK Block, NF AF Harris, PK Block, NF GP IEEE IEEE TI Potential damage to flight hardware from MIL-STD-462 CS02 setup SO 2003 IEEE SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, SYMPOSIUM RECORD, VOLS 1 AND 2 LA English DT Proceedings Paper CT IEEE Symposium on Electromagnetic Compatibility (EMC 2003) CY AUG 18-22, 2003 CL BOSTON, MA SP IEEE EMC Soc, Rhode & Schwarz, Curtis Strauss LLC, Sigrity, ETS Lindgren, Murata Elect, NA Inc, Dexter Magnet, Gateway Comp, Int Certificat Serv, Opt Filters, TUV Amer DE electromagnetic compatibility; testing; measurements AB The MIL-STD-462 CS02 conducted susceptibility test setup includes an audio transformer, with the secondary used as an inductor, and a large capacitor. Together, these two components form an L-type low-pass filter to minimize the injected test signal input into the power source. Some flight hardware power input configurations are not compatible with this setup and break into oscillation when powered up. This, in turn, can damage flight hardware. Such an oscillation resulted in the catastrophic failure of an item tested in the Goddard Space Flight Center (GSFC) Large electromagnetic compatibility (EMC) Test Facility. C1 Goddard Space Flight Ctr, Aerosp Technol Applicat Ctr, ManTech Adv Syst Int, Greenbelt, MD 20771 USA. RP Harris, PK (reprint author), Goddard Space Flight Ctr, Aerosp Technol Applicat Ctr, ManTech Adv Syst Int, Code 540-5, Greenbelt, MD 20771 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 0-7803-7835-0 PY 2003 BP 603 EP 606 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BX56M UT WOS:000185677200115 ER PT S AU Qiu, YM Uhl, D AF Qiu, YM Uhl, D GP IEEE IEEE TI Improved dot size uniformity and luminescence of InAs quantum dots on InP substrate SO 2003 INTERNATIONAL CONFERENCE INDIUM PHOSPHIDE AND RELATED MATERIALS, CONFERENCE PROCEEDINGS SE CONFERENCE PROCEEDINGS - INDIUM PHOSPHIDE AND RELATED MATERIALS LA English DT Proceedings Paper CT 15th International Conference on Indium Phosphide and Related Materials CY MAY 12-16, 2003 CL SANTA BARBARA, CA SP IEEE Lasers & Electro Opt Soc, IEEE Electron Devices Soc ID DASH LASERS; WAVELENGTH AB InAs self-organized quantum dots have been grown in InGaAs quantum well on InP substrates by metalorganic vapor phase epitaxy. We find out that the underlying InGaAs layer could affect the dot growth dramatically in terms of size distribution and luminescence efficiency. After inserting a thin GaAs interface, layer between the underlying InGaAs and the InAs QD layer, improved dot size uniformity and strong room temperature photoluminescence up to 2 pm were observed. The results-suggest that InAs from the underlying InGaAs layer contribute to the InAs QD formation, and cause the InAs QDs to be non-uniform, but a thin GaAs interface layer could effectively block the migration of In atoms from the InGaAs layer toward InAs QDs, and therefore lead to more uniform QD formation with better luminescence efficiency. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Qiu, YM (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 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 1092-8669 BN 0-7803-7704-4 J9 CONF P INDIUM PHOSPH PY 2003 BP 445 EP 447 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BW81D UT WOS:000183253000115 ER PT S AU Curkendall, DW Fielding, EJ Cheng, TH Pohl, JM AF Curkendall, DW Fielding, EJ Cheng, TH Pohl, JM BE Huang, CH Ramanujam, J TI A computational-grid based system for continental drainage network extraction using SRTM digital elevation models SO 2003 INTERNATIONAL CONFERENCE ON PARALLEL PROCESSING WORKSHOPS, PROCEEDINGS SE International Conference on Parallel Processing Workshops LA English DT Proceedings Paper CT International Conference on Parallel Processing CY OCT 06-09, 2003 CL KAOHSIUNG, TAIWAN SP Int Assoc Comp & Commun, Ohio State Univ, Natl Ctr High-Performance Comp, Natl Sun Yat-Sen Univ, Natl Cheng Kung Univ AB We describe a new effort for the computation of elevation derivatives using the Shuttle Radar Topography Mission (SRTM) results. Jet Populsion Laboratory's (JPL) SRTM has produced a near global database of highly accurate elevation data. The scope of this database enables computing precise stream drainage maps and other derivatives on Continental scales. We describe a computing architecture for this computationally very complex task based on NASA's Information Power Grid (IPG), a distributed high performance computing network based on the GLOBUS infrastructure. The SRTM data characteristics and unique problems they present are discussed. A new algorithm for organizing the conventional extraction algorithms [1] into a cooperating parallel grid is presented as an essential component to adapt to the IPG computing structure. Preliminary results are presented for a Southern California test area, established for comparing SRTM and its results against those produced using the USGS National Elevation Data (NED) model. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM dwc@jpl.nasa.gov; J.Fielding@jpl.nasa.gov; Tsan-Huei.Cheng@jpl.nasa.gov; jpohl@uwyo.edu NR 12 TC 4 Z9 4 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1530-2016 BN 0-7695-2018-9 J9 INT CONF PARA PROC PY 2003 BP 181 EP 190 DI 10.1109/ICPPW.2003.1240369 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BX92B UT WOS:000186827100022 ER PT B AU Ferebee, M Boeshaar, G Bush, K Hertz, J AF Ferebee, M Boeshaar, G Bush, K Hertz, J BE Marshall, CC Henry, G Delcambre, L TI An earth radiation budget experiment collection in the atmospheric sciences data center digital library SO 2003 JOINT CONFERENCE ON DIGITAL LIBRARIES, PROCEEDINGS LA English DT Proceedings Paper CT Joint Conference on Digital Libraries CY MAY 27-31, 2003 CL RICE UNIV, HOUSTON, TX SP IEEE TC Digital Lib, ACM SIGIR, ACM SIGWEB, Coalit Networked Informat, DELOS, Amer Soc Informat Sci & Technol HO RICE UNIV DE ERBE; narrative materials; rapid prototyping; long-term data preservation; user-centered design; permanent access; atmospheric science AB At the NASA Langley Research Center, the Earth Radiation Budget Experiment (ERBE) Data Management Team and the Atmospheric Sciences Data Center are developing a digital collection for the ERBE project. The main goal is long-term preservation of a comprehensive information environment. The secondary goal is to provide a context for these data products by centralizing the 25-year research project's scattered information elements. The development approach incorporates elements of rapid prototyping and user-centered design in a standards-based implementation. A working prototype is in testing with a small number of users. C1 NASA, Langley Res Ctr, Atmospher Sci Data Ctr, Hampton, VA 23681 USA. RP Ferebee, M (reprint author), NASA, Langley Res Ctr, Atmospher Sci Data Ctr, Hampton, VA 23681 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1939-3 PY 2003 BP 256 EP 257 PG 2 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA BW95C UT WOS:000183728000034 ER PT B AU Stoica, A Zebulum, RS Guo, X Keymeulen, D Ferguson, MI Duong, V AF Stoica, A Zebulum, RS Guo, X Keymeulen, D Ferguson, MI Duong, V BE Lohn, J Zebulum, R Steincamp, J Keymeulen, D Stoica, A Ferguson, MI TI Silicon validation of evolution-designed circuits SO 2003 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE LA English DT Proceedings Paper CT NASA/DoD Conference on Evolvable Hardware CY JUL 09-11, 2003 CL CHICAGO, IL SP NASA, US Dept Def AB No silicon fabrication and characterization of circuits with topologies designed by evolution has been done before, leaving open questions about the feasibility of the evolutionary design approach, as well as on how high-performance, robust, or portable such designs could really be when implemented in hardware. This paper is the first to report on a silicon implementation of circuits evolved in simulation. Several circuits were evolved and fabricated in 0.5-micron CMOS process; this paper focuses on results of logical gates evolved at transistor level. It discusses the steps taken in order to increase the chances of robust and portable designs, summarizes the results of characterization tests based on chip measurements, and comments on the performance comparing to simulations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM adrian.stoica@jpl.nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1977-6 PY 2003 BP 21 EP 25 PG 5 WC Computer Science, Hardware & Architecture SC Computer Science GA BX23V UT WOS:000184716500004 ER PT B AU Gwaltney, DA Ferguson, MI AF Gwaltney, DA Ferguson, MI BE Lohn, J Zebulum, R Steincamp, J Keymeulen, D Stoica, A Ferguson, MI TI Intrinsic hardware evolution for the design and reconfiguration of analog speed controllers for a DC motor SO 2003 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE LA English DT Proceedings Paper CT NASA/DoD Conference on Evolvable Hardware CY JUL 09-11, 2003 CL CHICAGO, IL SP NASA, US Dept Def AB Evolvable hardware provides the capability to evolve analog circuits to produce amplifier and filter functions. Conventional analog controller designs employ these same functions. Analog controllers for the control of the shaft speed of a DC motor are evolved on an evolvable hardware platform utilizing a second generation Field Programmable Transistor Array (FPTA2). The performance of an evolved controller is compared to that of a conventional proportional-integral (PI) controller It is shown that hardware evolution is able to create a compact design that provides good performance, while using considerably less functional electronic components than the conventional design. Additionally, the use of hardware evolution to provide fault tolerance by reconfiguring the design is explored. Experimental results are presented showing that significant recovery of capability can be made in the face of damaging induced faults. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM David.A.Gwaltney@nasa.gov; Michael.I.Ferguson@jpl.nasa.gov NR 17 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1977-6 PY 2003 BP 81 EP 90 PG 10 WC Computer Science, Hardware & Architecture SC Computer Science GA BX23V UT WOS:000184716500012 ER PT B AU Zebulum, RS Keymeulen, D Duong, V Guo, X Ferguson, MI Stoica, A AF Zebulum, RS Keymeulen, D Duong, V Guo, X Ferguson, MI Stoica, A BE Lohn, J Zebulum, R Steincamp, J Keymeulen, D Stoica, A Ferguson, MI TI Experimental results in evolutionary fault-recovery for field programmable analog devices SO 2003 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE LA English DT Proceedings Paper CT NASA/DoD Conference on Evolvable Hardware CY JUL 09-11, 2003 CL CHICAGO, IL SP NASA, US Dept Def ID EVOLVABLE HARDWARE; TRANSISTOR ARRAYS; ARCHITECTURES AB This paper presents experimental results of fast intrinsic evolutionary design and evolutionary fault recovery of a 4-bit Digital to Analog Converter (DAC) using the JPL stand-alone board-level evolvable system (SABLES). SABLES is Part of an effort to achieve integrated evolvable systems and provides autonomous, fast (tens to hundreds of seconds), on-chip evolution involving about 100,000 circuit evaluations. Its main components are a JPL Field Programmable Transistor Array (FPTA) chip used as transistor-level reconfigurable hardware, and a TI DSP that implements the evolutionary algorithm controlling the FPTA reconfiguration. The paper describes an experiment consisting of the hierarchical evolution of a 4-bit DAC using 20 cells of the FPTA chip. Fault-recovery is demonstrated after applying stuck-at 0 faults to all switches of one particular cell, and using evolution to recover functionality. It has been verified that the functionality can be recovered in less than one minute after the fault is detected while the evolutionary design of the 4-bit DAC from scratch took about 3 minutes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zebulum, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1977-6 PY 2003 BP 182 EP 186 PG 5 WC Computer Science, Hardware & Architecture SC Computer Science GA BX23V UT WOS:000184716500023 ER PT B AU Cozmuta, I O'Keeffe, J Stolc, V AF Cozmuta, I O'Keeffe, J Stolc, V GP IEEE IEEE TI Towards an MD simulation of ion currents in the alpha hemolysin channel SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western ID MOLECULAR-DYNAMICS; NUCLEIC-ACIDS; PORE; POLYMER AB Experiments show that single stranded nucleic acids polymers can be transported across an alpha hemolysin channel under the action of an applied electric field. The translocation of the nucleic acid polymers causes transient blockades in the ion current. The physical and chemical details of the interactions between polymer, channel and ionic solution that lead to the blockade events are not yet fully understood. Atomistic simulations enable a realistic description of the dynamic motions of the solvated polymer-pore system as a function of time. Analysis of such calculated system trajectories leads to valuable insight possible energy barriers, ion mobilities and short time-scale interactions. This study investigates the relationship between the structural properties of the alpha hemolysin channel and the ionic current blockades that result from the translocation of single stranded nucleic acids. C1 NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 USA. RP Cozmuta, I (reprint author), NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 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 BN 0-7803-7976-4 PY 2003 BP 187 EP 190 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900049 ER PT B AU Yamada, T AF Yamada, T GP IEEE IEEE TI Modeling of carbon nanotube Schottky barrier reduction for holes in air SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western ID ADSORPTION; CLUSTERS; OXYGEN AB A model is proposed for the previously reported lower Schottky barrier for holes Phi(Bh) in air than in vacuum at a metallic electrode-semiconducting carbon nanotube (CNT) junction. We consider that there is a transition region between the electrode and the CNT, and an appreciable potential can drop there. The role of the oxidation is to increase this potential drop with negatively charged oxygen molecules on the CNT, leading to lower Phi(Bh) after oxidation. The mechanism prevails in both p- and n-CNTs, and the model consistently explains the key experimental findings. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Yamada, T (reprint author), NASA, Ames Res Ctr, M-S 229-1, Moffett Field, CA 94035 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7976-4 PY 2003 BP 244 EP 247 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900063 ER PT B AU Mingo, N Yu, C Hao, Q Shi, L AF Mingo, N Yu, C Hao, Q Shi, L GP IEEE IEEE TI Theoretical analysis of SnO2 nanobelt thermal conductivity SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western AB Analysis of SnO2 nanobelt thermal conductivity data is performed by two methods: the adjustable cutoff Callaway method, and the real dispersion method. Analyses suggest a possible enhancement of the Umklapp scattering rate of 3 to 6 times that in the bulk material, although hotspots or other contact effects are not ruled out as alternative effects affecting the curves. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mingo, N (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 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 BN 0-7803-7976-4 PY 2003 BP 259 EP 262 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900067 ER PT B AU Qiu, YM Uhl, D Chacon, R Yang, RQ AF Qiu, YM Uhl, D Chacon, R Yang, RQ GP IEEE IEEE TI InAs quantum dot lasers on InP substrate SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western DE InAs quantum dots; quantum dot laser; InP ID DASH LASERS; MU-M; WAVELENGTH AB Single-stack InAs self-assembled quantum dot (QD) lasers based on InP substrates have been grown by metalorganic vapor phase epitaxy. The narrow ridge waveguide lasers lased up to 260 K in continuous wave operation, and near room temperature in pulsed mode, with emission wavelengths between 1.59 to 1.74 mum. Above 200 K, a very low wavelength temperature sensitivity of 0.09 nm/K was obtained, which is as low as that caused by the refractive index change. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Qiu, YM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7976-4 PY 2003 BP 364 EP 367 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900094 ER PT B AU Qiu, YM Gogna, P AF Qiu, YM Gogna, P GP IEEE IEEE TI Laterally coupled InAs quantum dot distributed feedback lasers at 1.3 mu m SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western DE InAs quantum dots; quantum dot lasers; distributed feedback lasers AB InAs quantum dot (QD) distributed feedback lasers at 1.3 mum were fabricated using four stacks of InAs QD's embedded within strained InGaAs quantum wells as an active region. The lasers show stable single mode continuous wave operation at temperature of 96 degreesC with sidemode suppression ratios of above 30 dB, threshold currents as low as 20 mA and output power up to 4 mW. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Qiu, YM (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 0-7803-7976-4 PY 2003 BP 414 EP 416 PG 3 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900107 ER PT B AU O'Keeffe, J Cozmuta, L Stolc, V O'Keeffe, J AF O'Keeffe, J Cozmuta, L Stolc, V O'Keeffe, J GP IEEE IEEE TI Polymer translocation through a nanopore: A geometry dependence study SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western ID POLYNUCLEOTIDE MOLECULES; PORE AB The translocation of a single stranded nucleic acid polymer through a nanopore, by an external electric field applied across the pore, may be well described by a 1-D drift-diffusion model. Translocation times and velocities are calculated for a homopolymer driven through a nanopore, where the polymerpore interaction dominates the polymer dynamics. In this model a purely electrostatic polymer-pore interaction is introduced, calculated from atomic charges on the polymer and pore. Simulation results show that the peak repulsion force occurs on the polymer during entry into the pore. In addition, the peak polymer-pore interaction is shown to decrease with polymer length for homopolymers with less than 20 nucleotides. The modeling results offer an explanation for the enhanced drift velocities experimentally observed for such short polymers. The dependence of the polymer translocation time on the pore geometry is investigated. For increasing pore radius the translocation velocity approaches the free space drift velocity for the surrounding ionic solution. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP O'Keeffe, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM jtok@nas.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 BN 0-7803-7976-4 PY 2003 BP 421 EP 424 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900109 ER PT B AU Lee, C Yang, EH Myung, NV George, T AF Lee, C Yang, EH Myung, NV George, T GP IEEE IEEE TI A nanochannel fabrication technique using chemical-mechanical polishing (CMP) and thermal oxidation SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western DE nanochannel; bionanotechnology; CMP; oxidation ID MOLECULES AB We have developed a new nanochannel fabrication technique using chemical-mechanical polishing (CMP) and thermal oxidation. With this technique, it is possible to control the width, length, and depth of the nanochannels without the need for nanolithography. The use of sacrificial SiO2 layers allows the fabrication of centimeter-long nanochannels. In addition, the fabrication process is CMOS compatible. We have successfully fabricated an array of extremely long and narrow nanochannels (i.e. 10 mm long, 25 nm wide and 100 nm deep) with smooth inner surfaces. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91106 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91106 USA. EM CHOONSUP.LEE@JPL.NASA.GOV 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 0-7803-7976-4 PY 2003 BP 553 EP 556 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900144 ER PT B AU Davis, JF Bronikowski, M Choi, D Epp, L Hoenk, M Hoppe, D Kowalczyk, B Noca, F Wong, E Hunt, B Adam, JD Young, RM Chang, B Jouzi, M Tzolov, M Yin, A Xu, J Adams, J Rogers, B AF Davis, JF Bronikowski, M Choi, D Epp, L Hoenk, M Hoppe, D Kowalczyk, B Noca, F Wong, E Hunt, B Adam, JD Young, RM Chang, B Jouzi, M Tzolov, M Yin, A Xu, J Adams, J Rogers, B GP IEEE IEEE TI High-Q mechanical resonator arrays based on carbon nanotubes SO 2003 THIRD IEEE CONFERENCE ON NANOTECHNOLOGY, VOLS ONE AND TWO, PROCEEDINGS LA English DT Proceedings Paper CT 3rd IEEE Conference on Nanotechnology (IEEE-NANO 2003) CY AUG 12-14, 2003 CL SAN FRANCISCO, CA SP IEEE Nanotechnol Council, IEEE Reg 6 Western DE carbon nanotube arrays; mechanical resonator arrays; rf filter array; nanomechanical resonator AB We present results of the characterization of a nanoelectromechanical signal-processing device based on arrays of carbon nanotubes embedded in RF waveguides. The design, fabrication, and operation of the device will be discussed, including initial RF measurements. Preliminary tests suggest that transmission of an RF signal through the array is associated with the mechanical resonance of the carbon nanotubes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Davis, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Choi, Daniel/A-8181-2017 NR 5 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7976-4 PY 2003 BP 635 EP 638 PG 4 WC Chemistry, Applied; Materials Science, Multidisciplinary; Physics, Applied SC Chemistry; Materials Science; Physics GA BX48B UT WOS:000185389900166 ER PT B AU Ponchak, GE Papapolymerou, J AF Ponchak, GE Papapolymerou, J BE Ponchak, GE TI 180 degree hybrid (rat-race) junction on CMOS grade silicon with a polyimide interface layer SO 2003 TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS, DIGEST OF PAPERS LA English DT Proceedings Paper CT Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems CY APR 09-11, 2003 CL GRAINAU, GERMANY SP IEEE Microwave Theory & Tech Soc, European Microwave Assoc, NASA Glenn Res Ctr, DaimlerChrysler AG, Tech Univ Munchen DE silicon; RFIC; hybrid coupler AB 180-degree hybrid junctions can be used to equally divide power between two output ports with either a 0 or 180-degree phase difference. Alternatively, they can be used to combine signals from two sources and output a sum and difference signal. The main limitation of implementing these on CMOS grade silicon is the high loss associated with the substrate. In this paper, we present a low loss 180-degree hybrid junction on CMOS grade (15 Omega-cm) silicon with a polyimide interface layer for the first time. The divider utilizes Finite Ground Coplanar (FGC) line technology, and operates at a center frequency of 15 GHz. C1 NASA, Glenn Res Ctr, Electron Device Technol Branch, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, Electron Device Technol Branch, 21000 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. NR 11 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7787-7 PY 2003 BP 96 EP 99 DI 10.1109/SMIC.2003.1196678 PG 4 WC Engineering, Electrical & Electronic; Physics, Condensed Matter SC Engineering; Physics GA BW58H UT WOS:000182494000025 ER PT S AU Whittle, J Saboo, J Kwan, R AF Whittle, J Saboo, J Kwan, R GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI From scenarios to code: An air traffic control case study SO 25TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING, PROCEEDINGS SE INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING LA English DT Proceedings Paper CT 25th International Conference on Software Engineering (ICSE 2003) CY MAY 03-10, 2003 CL PORTLAND, OR SP IEEE, IEEE Comp Soc, Tech Council Software Engn, ACM, ACM SIGSOFT, IBM, NORTHROP GRUMMAN Space Technol, BMW, NOKIA, SUN Microsyst, DaimlerChrysler, Microsoft Res ID SYSTEMS AB Two high profile workshops at OOPSLA and ICSE, an IEEE Computer article by David Harel and a growing number of research papers have all suggested algorithms that translate scenarios of a system's behavior into state machines. One of the uses of such algorithms is in the transition from requirements scenarios to component design. To date, however, most efforts have concentrated on the algorithmic details of the proposed translations. Less work has been done on evaluating these algorithms on a realistic case study. In this paper, we do exactly that for the algorithm presented in [10]. Our study is a component of an air traffic advisory system developed at NASA Ames Research Center. C1 NASA, Ames Res Ctr, QSS Grp, Ames, IA USA. RP Whittle, J (reprint author), NASA, Ames Res Ctr, QSS Grp, Ames, IA USA. NR 11 TC 12 Z9 12 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 0270-5257 BN 0-7695-1877-X J9 PROC INT CONF SOFTW PY 2003 BP 490 EP 495 DI 10.1109/ICSE.2003.1201227 PG 6 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BW77V UT WOS:000183140900045 ER PT S AU Moore, M Kaman, R Klein, M Asundi, J AF Moore, M Kaman, R Klein, M Asundi, J GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Quantifying the value of architecture design decisions: Lessons from the field SO 25TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING, PROCEEDINGS SE International Conference on Software Engineering LA English DT Proceedings Paper CT 25th International Conference on Software Engineering (ICSE 2003) CY MAY 03-10, 2003 CL PORTLAND, OR SP IEEE, IEEE Comp Soc, Tech Council Software Engn, ACM, ACM SIGSOFT, IBM, NORTHROP GRUMMAN Space Technol, BMW, NOKIA, SUN Microsyst, DaimlerChrysler, Microsoft Res AB This paper outlines experiences with using economic criteria to make architecture design decisions. It briefly describes the CBAM (Cost Benefit Analysis Method) framework applied to estimate the value of architectural strategies in a NASA project, the ECS. This paper describes the practical difficulties and experiences in applying the method to a large real-world system. It concludes with some lessons learned from the experience. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moore, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM mike.moore@nasa.gov; kazman@sei.cmu.edu; mk@sei.cmu.edu; asundi@utdallas.edu NR 7 TC 11 Z9 11 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 0270-5257 BN 0-7695-1877-X J9 PROC INT CONF SOFTW PY 2003 BP 557 EP 562 DI 10.1109/ICSE.2003.1201237 PG 6 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BW77V UT WOS:000183140900055 ER PT S AU Lutz, RR Mikulski, IC AF Lutz, RR Mikulski, IC GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Requirements discovery during the testing of safety-critical software SO 25TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING, PROCEEDINGS SE INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING LA English DT Proceedings Paper CT 25th International Conference on Software Engineering (ICSE 2003) CY MAY 03-10, 2003 CL PORTLAND, OR SP IEEE, IEEE Comp Soc, Tech Council Software Engn, ACM, ACM SIGSOFT, IBM, NORTHROP GRUMMAN Space Technol, BMW, NOKIA, SUN Microsyst, DaimlerChrysler, Microsoft Res AB This paper describes the role of requirements discovery during the testing of a safety-critical software system. Analysis of problem reports generated by the integration and system testing of an embedded, safety-critical software system identified four common mechanisms for requirements discovery and resolution during testing: (1) Incomplete requirements, resolved by changes to the software, (2) Unexpected requirements interactions, resolved by changes to the operational procedures, (3) Requirements confusion by the testers, resolved by changes to the documentation, and (4) Requirements confusion by the testers, resolved by a determination that no change was needed. The experience reported here confirms that requirements discovery during testing is frequently due to communication difficulties and subtle interface issues. The results also suggest that "false positive" problem reports from testing (in which the software behaves correctly but unexpectedly) provide a rich source of requirements information that can be used to reduce operational anomalies in critical systems. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Lutz, RR (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. NR 10 TC 4 Z9 4 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 0270-5257 BN 0-7695-1877-X J9 PROC INT CONF SOFTW PY 2003 BP 578 EP 583 DI 10.1109/ICSE.2003.1201240 PG 6 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BW77V UT WOS:000183140900058 ER PT S AU Feather, MS Nikora, AP Heitmeyer, CL Mead, NR AF Feather, MS Nikora, AP Heitmeyer, CL Mead, NR GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI ICSE 2003 workshop on software engineering for high assurance systems: Synergies between process, product, and profiling (SEHAS 2003) SO 25TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING, PROCEEDINGS SE International Conference on Software Engineering LA English DT Proceedings Paper CT 25th International Conference on Software Engineering (ICSE 2003) CY MAY 03-10, 2003 CL PORTLAND, OR SP IEEE, IEEE Comp Soc, Tech Council Software Engn, ACM, ACM SIGSOFT, IBM, NORTHROP GRUMMAN Space Technol, BMW, NOKIA, SUN Microsyst, DaimlerChrysler, Microsoft Res ID RELIABILITY; RISK AB A critical issue in software engineering is how to construct high assurance software systems, i.e., software systems where compelling evidence is required that the system delivers its services in a manner satisfying critical properties, such as safety and security. This two-day ICSE workshop, the third in a series of workshops on high assurance systems, will provide a forum for researchers and practitioners to exchange ideas and experiences' relevant to the development of software for aerospace systems, medical systems, systems controlling nuclear power plants, and other critical systems. Participants of the SEHAS 2003 workshop will explore the opportunities for, and benefits of, synergies between three important themes-product, process, and profiling-each theme reflecting an important aspect of software development for high assurance systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM martin.s.feather@jpl.nasa.gov; allen.p.nikora@jpl.nasa.gov; heitmeyer@itd.nrl.navy.mil; nrm@sei.cmu.edu RI Heitmeyer, Constance/F-6500-2011; OI Heitmeyer, Constance/0000-0001-7942-9309; Mead, Nancy/0000-0002-2919-086X NR 16 TC 0 Z9 0 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 0270-5257 BN 0-7695-1877-X J9 PROC INT CONF SOFTW PY 2003 BP 787 EP 788 DI 10.1109/ICSE.2003.1201286 PG 2 WC Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BW77V UT WOS:000183140900104 ER PT B AU Feather, MS Cornford, SL Hicks, KA AF Feather, MS Cornford, SL Hicks, KA GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Descoping SO 27TH ANNUAL NASA GODDARD/IEEE SOFTWARE ENGINEERING WORKSHOP - PROCEEDINGS LA English DT Proceedings Paper CT 27th Annual NASA Goddard/IEEE Software Engineering Workshop (SEW-27 2002) CY DEC 05-06, 2002 CL Greenbelt, MD SP IEEE Comp Soc Tech Council Software Engn, NASA Goddard Space Flight Ctr, Software Engn Lab AB Descoping is the strategic abandonment and/or weakening of objectives. It is required whenever limited resources preclude satisfactory attainment of all those objectives. Potential causes of the need for descoping are numerous, and descoping is a recurring phenomenon during project planning and development. We present an approach which facilitates descoping. It is founded upon a quantitative model of requirements attainment, resource consumption, and risk. Features of this model allow for the representation of interactions between objectives. Measures derived from this qualitative model support the identification and evaluations of descope options. Tool support for the model gives assistance to users in making their descope decisions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Martin.S.Feather@Jpl.Nasa.Gov; Steven.L.Cornfield@Jpl.Nasa.Gov; Kenneth.A.Hicks@Jpl.Nasa.Gov NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1855-9 PY 2003 BP 107 EP 113 DI 10.1109/SEW.2002.1199456 PG 7 WC Computer Science, Software Engineering SC Computer Science GA BX82Y UT WOS:000186577600013 ER PT B AU Behnke, J Byrnes, JB AF Behnke, J Byrnes, JB GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Requirements engineering in science data processing systems SO 27TH ANNUAL NASA GODDARD/IEEE SOFTWARE ENGINEERING WORKSHOP - PROCEEDINGS LA English DT Proceedings Paper CT 27th Annual NASA Goddard/IEEE Software Engineering Workshop (SEW-27 2002) CY DEC 05-06, 2002 CL Greenbelt, MD SP IEEE Comp Soc Tech Council Software Engn, NASA Goddard Space Flight Ctr, Software Engn Lab AB Science data processing is a component of most research and development programs nationally and internationally and is a prime focus of work performed at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Requirements engineering is probably the most important phase in the software development lifecycle and there are many ways requirements engineering is performed by different projects. Comparisons and contrasts can be made about how science products are specified, created and managed by different projects. Identification of these characteristics leads to a better understanding of how requirements engineering is performed and how it can be improved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Behnke, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1855-9 PY 2003 BP 114 EP 120 DI 10.1109/SEW.2002.1199457 PG 7 WC Computer Science, Software Engineering SC Computer Science GA BX82Y UT WOS:000186577600014 ER PT B AU Truszkowski, W Rouff, C AF Truszkowski, W Rouff, C GP IEEE COMPUTER SOCIETY IEEE COMPUTER SOCIETY TI Progressive autonomy: A method for gradually introducing autonomy into space missions SO 27TH ANNUAL NASA GODDARD/IEEE SOFTWARE ENGINEERING WORKSHOP - PROCEEDINGS LA English DT Proceedings Paper CT 27th Annual NASA Goddard/IEEE Software Engineering Workshop (SEW-27 2002) CY DEC 05-06, 2002 CL Greenbelt, MD SP IEEE Comp Soc Tech Council Software Engn, NASA Goddard Space Flight Ctr, Software Engn Lab AB This paper presents a method under development for introducing autonomy and agent-based software into future space and ground-based missions while both reducing the risk of mission failures and gaining the confidence and support of mission management and Principal Investigators (PIs). This is being done by using a mechanism to support dynamic agent-community evolution (e.g., agents adapting to community changes, agents joining a community or agents leaving a community). This dynamic capability of agents is necessary to achieve what we call "progressive autonomy", which will allow the gradual introduction of autonomy and agent technology into missions without having to commit to the technology from the start. It will also allow the dynamic modification of satellite systems using agent migration to update and modify spacecraft capabilities on an as-needed basis, as well as allow the introduction of mission management and autonomy into existing missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Truszkowski, W (reprint author), NASA, Goddard Space Flight Ctr, Code 588-0, Greenbelt, MD 20771 USA. NR 15 TC 0 Z9 0 U1 1 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1855-9 PY 2003 BP 164 EP 171 DI 10.1109/SEW.2002.1199464 PG 8 WC Computer Science, Software Engineering SC Computer Science GA BX82Y UT WOS:000186577600020 ER PT S AU Dynys, FW AF Dynys, FW BE Kriven, WM Lin, HT TI Ceramic spheres derived from cation exchange beads SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Porous ZrO2 and hollow TiO2 spheres were synthesized from a strong acid cation exchange resin. Spherical cation exchange beads, polystyrene based polymer, were used as a morphological-directing template. Aqueous ion exchange reaction was used to chemically bind (ZrO)(+2) ions to the polystyrene structure. The pyrolysis of the polystyrene at 600 degreesC produces porous ZrO2 spheres with a surface area of 24 m(2)/g with a mean sphere size of 42 mum. Hollow TiO2 spheres were synthesized by using the beads as a micro-reactor. A direct surface reaction between titanium isopropoxide and the resin beads forms a hydrous TiO2 shell around the polystyrene core. The pyrolysis of the polystyrene core at 600 degreesC produces hollow anatase spheres with a surface area of 42 m(2)/g with a mean sphere size of 38 mum. The formation of ceramic spheres was studied by XRD, SEM and B.E.T. nitrogen adsorption measurements. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dynys, FW (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 1 U2 2 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 147 EP 152 PG 6 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200022 ER PT S AU Choi, SR Bansal, NP AF Choi, SR Bansal, NP BE Kriven, WM Lin, HT TI High-temperature flexure strength, fracture toughness and fatigue of zirconia/alumina composites SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Various electrolyte materials for solid oxide fuel cells were fabricated by hot pressing 10 mol % yttria-stabilized zirconia (10-YSZ) reinforced with two different forms of alumina particulates and platelets - each containing 0 to 30 mol % alumina. Flexure strength and fracture toughness of platelet composites were determined as a function of alumina content at 1000degreesC in air and compared with those of particulate composites determined previously. Elevated-temperature strength and fracture toughness of both composite systems increased with increasing alumina content. For a given alumina content, flexure strength of particulate composites was greater than that of platelet composites at higher alumina contents (greater than or equal to20 mol %) while fracture toughness was greater in platelet composites than in particulate composites, regardless of alumina content. The results of slow crack growth (SCG) testing at 1000degreesC showed that susceptibility to SCG was greatest with SCG parameter n = 6-8 for both 0 and 30 mol % particulate composites and was least with n = 33 for the 30 mol % platelet composite. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 14 TC 2 Z9 2 U1 1 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 273 EP 279 PG 7 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200041 ER PT S AU Zhu, DM Choi, SR Eldridge, JI Lee, KN Miller, RA AF Zhu, DM Choi, SR Eldridge, JI Lee, KN Miller, RA BE Kriven, WM Lin, HT TI Surface cracking and interface reaction associated delamination failure of thermal and environmental barrier coatings SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc ID CONDUCTIVITY; GRADIENT AB In this paper, surface cracking and interface reactions of a barium-strontium-aluminosilicate (BSAS) coating and a multi-layer ZrO2-8Wt%Y2O3 and mullite/BSAS/Si thermal and environmental barrier coating system on SiC/SiC ceramic matrix composites were characterized after long-term combined laser thermal gradient and furnace cyclic tests in a water vapor containing environment. The surface cracking was analyzed based on the coating thermal gradient sintering behavior and thermal expansion mismatch stress characteristics under the thermal cyclic conditions. The interface reactions, which were largely enhanced by the coating surface cracking in the water vapor environment, were investigated in detail, and the reaction phases were identified for the coating system after the long-term exposure. The accelerated coating delamination failure was attributed to the increased delamination driving force under the thermal gradient cyclic loading and the reduced interface adhesion due to the detrimental interface reactions. C1 NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhu, DM (reprint author), NASA, John H Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 7 TC 1 Z9 1 U1 1 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 469 EP 475 PG 7 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200067 ER PT S AU Eldridge, JI Spuckler, CM Nesbitt, JA Street, KW AF Eldridge, JI Spuckler, CM Nesbitt, JA Street, KW BE Kriven, WM Lin, HT TI Health monitoring of thermal barrier coatings by mid-infrared reflectance SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Mid-infrared (MIR) reflectance is shown to be a powerful tool for monitoring the integrity of 8wt% yttria-stabilized zirconia (8YSZ) thermal barrier coatings (TBCs). Because of the translucent nature of plasma-sprayed 8YSZ TBCs, particularly at MIR wavelengths (3 to 5 gm), measured reflectance does not only originate from the TBC surface, but contains strong contributions from internal scattering within the coating as well as reflectance from the underlying TBC/substrate interface. Therefore, changes in MIR reflectance measurements can be used to monitor the progression of TBC delamination. In particular, MIR reflectance is shown to reproducibly track the progression of TBC delamination produced by repeated thermal cycling (to 1163degreesC) of plasma-sprayed 8YSZ TBCs on Rend N5 superalloy substrates. To understand the changes in MIR reflectance with the progression of a delamination crack network, a four-flux pure-scattering model is used to predict the increase in MIR reflectance produced by the introduction of these cracks. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Eldridge, JI (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 6 TC 8 Z9 8 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 511 EP 516 PG 6 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200073 ER PT S AU Zhu, DM Chen, YL Miller, RA AF Zhu, DM Chen, YL Miller, RA BE Kriven, WM Lin, HT TI Defect clustering and nano-phase structure characterization of multi-component rare earth oxide doped zirconia-yttria thermal barrier coatings SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Advanced thermal barrier coatings (TBCs) have been developed by incorporating multicomponent rare earth oxide dopants into zirconia-based thermal barrier coatings to promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nano-phases within the coating systems. In this paper, the defect clusters, induced by Nd, Gd, and Yb rare earth dopants in the zirconia-yttria thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The TEM lattice imaging, selected area diffraction (SAD) and electron energy loss spectroscopy (EELS) analyses demonstrated that the extensive nano-scale rare earth dopant segregation exists in the plasma-sprayed and electron-physical-vapor-deposited (EB-PVD) thermal barrier coatings. The nano-scale concentration heterogeneity and the resulting large lattice distortion promoted the formation of parallel and rotational defective lattice clusters in the coating systems. The presence of the 5 to 100 nm sized defect clusters and nanophases is believed to be responsible for the significant reduction of thermal conductivity, improved sintering resistance and long-term high temperature stability of the advanced thermal barrier coating systems. C1 USA, NASA, Glenn Res Ctr, Res Lab,Vehicle Technol Directorate, Cleveland, OH 44135 USA. RP Zhu, DM (reprint author), USA, NASA, Glenn Res Ctr, Res Lab,Vehicle Technol Directorate, Cleveland, OH 44135 USA. NR 7 TC 23 Z9 23 U1 4 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 525 EP 534 PG 10 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200075 ER PT S AU Choi, SR Zhu, DM Miller, RA AF Choi, SR Zhu, DM Miller, RA BE Kriven, WM Lin, HT TI Mixed-mode fracture of plasma-sprayed thermal barrier coatings at ambient and elevated temperatures SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: A SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc ID II FRACTURE; TOUGHNESS; CERAMICS; BEHAVIOR AB Mixed-mode fracture behavior of plasma-sprayed ZrO2-8 Wt% Y2O3 thermal barrier coatings was determined in air at 25 and 1316degreesC using an asymmetric four-point flexure in conjunction with the single edge v-notched beam (SEVNB) test specimens. Mode I fracture toughness was found to be K-Ic=1.15+/-0.07 and 0.98+/-0.13 MParootm, respectively, at 25 and 1316degreesC; whereas respective mode II fracture toughness was K-IIc=0.73+/-0.10 and 0.65+/-0.04 MParootm. The ratio of mode I to mode II fracture toughness was K-IIc/K(Ic)approximate to0.65 at both temperatures. The empirical mixed-mode fracture criterion well described the coatings' mixed-mode fracture behavior among the four mixed-mode fracture theories considered. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 22 TC 0 Z9 0 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 3 BP 555 EP 560 PG 6 WC Electrochemistry; Materials Science, Ceramics; Materials Science, Biomaterials; Materials Science, Characterization & Testing; Materials Science, Composites SC Electrochemistry; Materials Science GA BY46D UT WOS:000189318200079 ER PT S AU Hurwitz, FI Shinavski, RJ AF Hurwitz, FI Shinavski, RJ BE Kriven, WM Lin, HT TI Alternative interphase coatings for improved durability in SiC/SiC composites SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc ID BORON-NITRIDE; ALUMINUM NITRIDE AB Boron nitride coatings are typically used to effect a mechanically weak bond or compliant interphase in SiC/SiC composites. However, BN is moisture sensitive and subject to degradation with loss of boria, particularly at intermediate temperatures (850-950degreesC). The current work examines the influence of an Al dopant in a low temperature, vapor derived BN, as well as a dual layer AlN/BN interphase coating, on composite durability under stress rupture conditions in air at 950 an 1200degreesC. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hurwitz, FI (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 8 TC 1 Z9 1 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 231 EP 237 PG 7 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400034 ER PT S AU Yun, HM DiCarlo, JA Bhatt, RT Hurst, JB AF Yun, HM DiCarlo, JA Bhatt, RT Hurst, JB BE Kriven, WM Lin, HT TI Processing and structural advantages of the sylramic-iBN SiC fiber for SiC/SiC components SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB The successful high-temperature application of complex-shaped SiC/SiC components will depend on achieving as high a fraction of the as-produced fiber strength as possible: during component fabrication and service. Key issues center on a variety of component architecture, processing, and service-related factors that can reduce fiber strength, such as fiber-fiber abrasion during architecture shaping, surface chemical attack during interphase deposition and service, and intrinsic flaw growth during high-temperature matrix formation and composite creep. The objective of this paper is to show that the NASA-developed Sylramici-BN SiC fiber minimizes many of these issues for state-of-the-art melt-infiltrated (MI) SiC/BN/SiC composites. To accomplish this, data from various mechanical tests are presented that compare how different high performance SiC fiber types retain strength during formation of complex architectures, during processing of BN interphases and MI matrices, and during simulated composite service at high temperatures. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Yun, HM (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 11 TC 7 Z9 7 U1 2 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 247 EP 253 PG 7 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400036 ER PT S AU Robinson, RC Verrilli, MJ AF Robinson, RC Verrilli, MJ BE Kriven, WM Lin, HT TI Testing and characterization of CMC combustor liners SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Multiple combustor liner applications, both segmented and fully annular designs, have been configured for exposure in NASA's High Pressure Burner Rig (HPBR). The segmented liners were attached to the rig structure with SiC/SiC fasteners and exposed to simulated gas turbine conditions for nearly 200 hours. Test conditions included pressures of 6 atm., gas velocity of 42 m/s, and gas temperatures near 1450degreesC. The temperatures of both the cooled and combustion flow sides of the liners were measured using optical and contact measurement techniques. Minor weight loss was observed, but the liners remained structurally sound, although damage was noted in some fasteners. C1 NASA, QSS Grp Inc, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Robinson, RC (reprint author), NASA, QSS Grp Inc, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 275 EP 280 PG 6 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400040 ER PT S AU Calomino, AM Verrilli, MJ AF Calomino, AM Verrilli, MJ BE Kriven, WM Lin, HT TI Specimen scale effects on the stress-oxidation behavior of a carbon fiber reinforced silicon carbide matrix composite SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Specimen scale effect on the stress-rupture behavior of a carbon fiber reinforced chemical vapor infiltrated silicon carbide matrix composite (C/SiC) was examined by varying the gage section width. Average rupture lives at a stress of 207 MPa were obtained at two temperatures, 800 and 1200 degreesC, for specimens having three different gage section widths. Results show that the rupture life of the composite specimen increased with increasing specimen width at both test temperatures. Metallographic examinations revealed significant differences in fiber oxidation damage patterns at 800 degreesC compared to 1200 degreesC. Damage patterns for each specimen type are presented and discussed C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Calomino, AM (reprint author), NASA, Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 8 TC 0 Z9 0 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 289 EP 294 PG 6 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400042 ER PT S AU Bhatt, RT McCue, TR DiCarlo, JA AF Bhatt, RT McCue, TR DiCarlo, JA BE Kriven, WM Lin, HT TI Thermal stability of melt infiltrated SiC/SiC composites SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB To determine their rnicrostructural and strength stability, SiC/SiC composites with Sylramic-iBN SiC fibers and chemically vapor infiltrated (CVI) SiC plus melt-infiltrated silicon matrices were thermally exposed at 1300, 1350 and 1400degreesC for 100 and 500 hr in air. The un-exposed and exposed composites were tensile tested at room temperature, and their fracture surfaces and microstructures analyzed by scanning electron microscopy. Results indicated that these composites were relatively stable for up to 500 hr at 1300degreesC. Beyond this time/temperature envelope, ultimate strength degradation was observed which is influenced by the volume fraction of CVI SiC matrix. The dominant strength degradation mechanism for the composites appeared to be degradation of SiC fibers due to reaction with silicon that diffuses through the CVI SiC. Residual strength of the composites after thermal exposure was modeled by theories based on thermally-activated diffusion processes. C1 USA, NASA, Glenn Res Ctr, Res Lab, Cleveland, OH 44135 USA. RP Bhatt, RT (reprint author), USA, NASA, Glenn Res Ctr, Res Lab, Cleveland, OH 44135 USA. NR 6 TC 7 Z9 7 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 295 EP 300 PG 6 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400043 ER PT S AU Abdul-Aziz, A Bhatt, RT Baaklini, G AF Abdul-Aziz, A Bhatt, RT Baaklini, G BE Kriven, WM Lin, HT TI Thermal barrier coating and cooling hole size effects on the thermo-mechanical response of cooled silicon nitride plate SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Steady state thermal analysis with coupled stress analyses were conducted to study the effect of cooling hole geometries on a silicon nitride (Si3N4) cooling plate. The plate was subjected to a simulated burner rig thermal boundary conditions. The application of a thermal barrier coating (TBC) to the side that is exposed to the hot gases are also included. The presence of the TBC was able to reduce the temperature in the substrate by at least 7% resulting in a decrease in the maximum principal stress by 33%. The larger the cooling holes and the smaller spacing in between further reduced the temperature and consequently the stresses. C1 Cleveland State Univ, NASA, Glenn Resident Res Assoc, Dept Civil & Environm Engn, Cleveland, OH 44135 USA. RP Abdul-Aziz, A (reprint author), Cleveland State Univ, NASA, Glenn Resident Res Assoc, Dept Civil & Environm Engn, 21000 Brook Pk Rd,MS 6-1, Cleveland, OH 44135 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 317 EP 324 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400046 ER PT S AU Salem, JA Powers, L AF Salem, JA Powers, L BE Kriven, WM Lin, HT TI Guidelines for the testing of plates SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE Ceramic Engineering and Science Proceedings LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB The strength of ceramics and glasses under biaxial stress is of interest for the verification of life prediction models and codes. Biaxial strength testing is also a convenient method for testing components such as substrates and optical pieces such as windows. The convenience arises because edge effects can be minimize or eliminated, and plate-like components can be tested in the as-processed condition. Further, plates more efficiently sample the distribution of surface flaws, machining related or otherwise. Recently, the ASTM standard test method C 1499 for biaxial strength testing via concentric ring loading was developed and published [1]. The guidelines defined in the biaxial strength standard are derived and discussed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Salem, JA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 15 Z9 15 U1 0 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 357 EP 364 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400052 ER PT S AU Verrilli, MJ DiCarlo, JA Yun, HM Barnett, TR AF Verrilli, MJ DiCarlo, JA Yun, HM Barnett, TR BE Kriven, WM Lin, HT TI Hoop tensile characterization of SiC/SiC cylinders fabricated from 2D fabric SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC cylinders using ring specimens machined from the cylinder ends. The cylinders were fabricated from 2D balanced fabric with several material variants, including wall thickness (6, 8, and 12 plies), SiC fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI SiC, and partial CVI plus melt-infiltrated SiC-Si). Fiber ply splices existed in the all the hoops. Tensile hoop measurements were made at room temperature and 1200degreesC using hydrostatic ring test facilities. The hoop results are compared with in-plane data measured on flat panels using same material variants, but containing no splices. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Verrilli, MJ (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 407 EP 413 PG 7 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400059 ER PT S AU Kalluri, S Verrilli, MJ AF Kalluri, S Verrilli, MJ BE Kriven, WM Lin, HT TI Influence of holes on the in-plane tensile strength and fatigue durability of a Nicalon(TM)/Si-N-C ceramic matrix composite SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Effects of different sizes of holes as well as different percentages of open areas on the in-plane tensile strength and fatigue durability of the SiC/Si-N-C composite were investigated in this study. Test specimens with no holes, four different diameters of holes (1.0 to 3.2 mm), and four different open areas (20 to 35%) were machined. All mechanical testing was performed in air at a temperature of 910 degreesC. Fatigue tests were conducted with a load ratio, R = 0.05, and a frequency of 0.33 Hz. In general, both the in-plane tensile strength of the composite and its fatigue durability decreased with an increase in the size of the hole and percentage of the open area. Reductions in the in-plane tensile strength and cyclic fatigue life of the composite were described by empirical equations with the diameter of the hole and the percent open area as the independent variables. The applicability of these two empirical equations was evaluated with additional tensile and fatigue test data generated on the composite specimens. C1 NASA, Glen Res Ctr, Ohio Aerosp Inst, Brookpark, OH 44135 USA. RP Kalluri, S (reprint author), NASA, Glen Res Ctr, Ohio Aerosp Inst, 21000 Brookpk Rd,M-S 49-7, Brookpark, OH 44135 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 427 EP 434 PG 8 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400062 ER PT S AU Choi, SR Bansal, NP Gyekenyesi, JP AF Choi, SR Bansal, NP Gyekenyesi, JP BE Kriven, WM Lin, HT TI Rate dependency of shear strength in SiC/BSAS ceramic matrix composite at elevated temperature SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc ID CFCCS AB Both interlaminar and in-plane shear strengths of a unidirectional Hi-Nicalon(TM) fiber-reinforced barium strontium aluminosilicate (SiC/BSAS) composite were determined at 1100degreesC in air as a function of test rate using double notch shear (DNS) test specimens. The composite exhibited a significant effect of test rate on shear strength, regardless of orientation which was either in interlaminar or in in-plane region, resulting in an appreciable shear-strength degradation of about 50 % as test rate decreased from 3.3x10(-1) mm/s to 3.3x10(-5) mm/s. The rate dependency of composite's shear strength was very similar to that of ultimate tensile strength at 1100degreesC observed in a similar composite (2-D SiC/BSAS).. A phenomenological, power-law slow crack growth formulation was proposed to account for the rate dependency of shear strength of the composite. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Choi, SR (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 435 EP 441 PG 7 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400063 ER PT S AU Verrilli, MJ Calomino, A AF Verrilli, MJ Calomino, A BE Kriven, WM Lin, HT TI Temperature dependence on the strength and stress rupture behavior of a carbon-fiber reinforced silicon carbide matrix (C/SiC) composite SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB Tensile strengths and stress rupture lives of carbon- fiber reinforced silicon carbide (C/SiC) specimens were measured at 800 degreesC and are compared to previously reported 1200 degreesC data. All tests were conducted in an environmental chamber containing 1000 ppm of oxygen in argon. The average 800 degreesC tensile strength of 610 MPa is 10% greater than at 1200 degreesC. Average stress rupture lives at 800 degreesC were 2.5 times longer than those obtained at 1200 degreesC. The difference in the 800 and 1200 degreesC lives is related to the oxidation rate of the reinforcing carbon fibers, which is the primary damage mode of C/SiC composites in oxygen-containing environments. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Verrilli, MJ (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 9 TC 8 Z9 8 U1 0 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 443 EP 449 PG 7 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400064 ER PT S AU DiCarlo, JA Bhatt, RT McCue, TR AF DiCarlo, JA Bhatt, RT McCue, TR BE Kriven, WM Lin, HT TI Modeling the thermostructural stability of melt-infiltrated SiC/SiC composites SO 27TH INTERNATIONAL COCOA BEACH CONFERENCE ON ADVANCED CERAMICS AND COMPOSITES: B SE CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS LA English DT Proceedings Paper CT 27th International Cocoa Beach Conference on Advanced Ceramics Composites CY JAN 26-31, 2003 CL COCOA BEACH, FL SP Amer Ceram Soc AB SiC/SiC composites developed by NASA with Sylramic-iBN fibers and melt-infiltrated (MI) SiC-Si matrices have demonstrated 1000-hour rupture life in air at 100 MPa and 1315degreesC. Recently it has been determined that a major factor controlling the long-term rupture life of these composites is not environment or stress, but an intrinsic microstructural and strength instability caused by a thermally-induced silicon attack of the SiC fibers. The objective of this paper is to present a simple diffusion-based analytical model which predicts well the observed effects of stress-free thermal exposure on the residual tensile strength of Sylramic-iBN/SiC-Si composites. The practical implications of the model for SiC/SiC composites with MI matrices are discussed. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DiCarlo, JA (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 0196-6219 J9 CERAM ENG SCI PROC PY 2003 VL 24 IS 4 BP 465 EP 470 PG 6 WC Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Composites SC Materials Science GA BY46E UT WOS:000189318400067 ER PT B AU Abrams, MA Cavalli, RM Pignatti, S AF Abrams, MA Cavalli, RM Pignatti, S GP IEEE IEEE TI Intercalibration and fusion of satellite and airborne multispectral data over Venice SO 2ND GRSS/ISPRS JOINT WORKSHOP ON REMOTE SENSING AND DATA FUSION OVER URBAN AREAS LA English DT Proceedings Paper CT 2nd GRS/ISPRS Joint Workshop on Remote Sensing and Data Fusion over Urban Areas CY MAY 22-23, 2003 CL TECH UNIV BERLIN, BERLIN, GERMANY SP IEEE Geosci & Remote Sensing, European Space Agcy, Eurimage SpA, Geosystems GmbH, PCI Geomat Grp Ltd, FPK Ingenieur Gesell mbH, Taylor & Francis Grp plc, Pietruska Verlag & Geo Datenbanken GmbH HO TECH UNIV BERLIN C1 NASA, JPL, Pasadena, CA USA. RP Abrams, MA (reprint author), NASA, JPL, 4800 Oak Grove Dr, Pasadena, CA 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 0-7803-7719-2 PY 2003 BP 241 EP 242 DI 10.1109/DFUA.2003.1219995 PG 2 WC Computer Science, Interdisciplinary Applications; Remote Sensing; Imaging Science & Photographic Technology SC Computer Science; Remote Sensing; Imaging Science & Photographic Technology GA BX64V UT WOS:000185947700050 ER PT B AU Oyafuso, F Klimeck, G Bowen, RC Boykin, T von Allmen, P AF Oyafuso, F Klimeck, G Bowen, RC Boykin, T von Allmen, P BE Stutzmann, M TI Disorder induced broadening in multimillion atom alloyed quantum dot systems SO 2ND INTERNATIONAL CONFERENCE ON SEMICONDUCTOR QUANTUM DOTS LA English DT Proceedings Paper CT 2nd International Conference on Semiconductor Quantum Dots CY SEP 30-OCT 03, 2002 CL UNIV TOKYO, KOMABA CAMPUS, TOKYO, JAPAN HO UNIV TOKYO, KOMABA CAMPUS ID SIMULATION AB Disorder-induced broadening of the conduction and valence band eigenenergies is calculated for an ensemble of dome-shaped In0.6Ga0.4As quantum dots of diameter 30 nm using an sp(3)d(5)s* tight binding model. An assumption is made that there is no alloy clustering, so that neighboring cations are uncorrelated. For this case, it is found that the contribution to the broadening from alloy disorder is small (less than 0.35 meV) relative to the total broadening determined from photoluminescence experiments and sensitive to the applied boundary conditions, so that care must be taken to ensure proper convergence of the numerical results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Oyafuso, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-315, Pasadena, CA 91109 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 17 TC 3 Z9 3 U1 0 U2 1 PU WILEY-VCH, INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA BN 3-527-40464-3 PY 2003 BP 1149 EP 1152 DI 10.1002/pssc.200303020 PG 4 WC Physics, Condensed Matter SC Physics GA BX68D UT WOS:000186108000015 ER PT B AU Im, E Li, L Haddad, ZS AF Im, E Li, L Haddad, ZS GP AMS TI Retrieving rain drop size distribution from dual-frequency wind profiler SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Im, E (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 14 EP 17 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300005 ER PT B AU Tanelli, S Meagher, J Durden, SL Im, E AF Tanelli, S Meagher, J Durden, SL Im, E GP AMS TI Multiparametric airborne radar observations of the melting layer during the Wakasa Bay experiment SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanelli, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-243, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 33 EP 34 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300010 ER PT B AU Li, XW Tao, WK Simpson, J Khain, A Johnson, D AF Li, XW Tao, WK Simpson, J Khain, A Johnson, D GP AMS TI Radar reflectivity simulated by a 2-D spectral bin model and its sensitivity on cloud-aerosol interaction SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Li, XW (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 39 EP 40 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300012 ER PT B AU Im, E Li, L Haddad, ZS AF Im, E Li, L Haddad, ZS GP AMS TI Retrieving rain drop size distribution from dual-frequency wind profiler SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Im, E (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 41 EP 44 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300013 ER PT B AU Tian, L Heymsfield, G Li, LH AF Tian, L Heymsfield, G Li, LH GP AMS TI Stratiform precipitation observed by airborne radar at 94 and 10 GHz SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tian, L (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 45 EP 46 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300014 ER PT B AU Wang, JJ AF Wang, JJ GP AMS TI Rainfall characteristics and kinematic structure of a mesoscale convwction observed during the onset of South East Asian Monsoon SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 Univ Maryland Baltimore Cty, Goddard Ctr Earth Sci & Technol, Mesoscale Atmospher Proc Branch, NASA,Goddard Space Flight Ctr, Greenbelt, MD USA. RP Wang, JJ (reprint author), Univ Maryland Baltimore Cty, Goddard Ctr Earth Sci & Technol, Mesoscale Atmospher Proc Branch, NASA,Goddard Space Flight Ctr, Greenbelt, MD USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 74 EP 77 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300022 ER PT B AU Rickenbach, TM Belcher, L Kucera, P Carey, L Halverson, J Starr, D AF Rickenbach, TM Belcher, L Kucera, P Carey, L Halverson, J Starr, D GP AMS TI Anvil evolution from NEXRAD data during CRYSTAL-FACE SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rickenbach, TM (reprint author), NASA, Goddard Space Flight Ctr, Code 921, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 96 EP 99 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300028 ER PT B AU Heymsfield, GM Li, LH Tian, L McGill, M Wang, Z AF Heymsfield, GM Li, LH Tian, L McGill, M Wang, Z GP AMS TI Thunderstorm generated cirrus observed from X and W-BAND airborne radar during crystal-face SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Heymsfield, GM (reprint author), Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. RI McGill, Matthew/D-8176-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 185 EP 186 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300054 ER PT B AU Li, LH Heymsfield, GM Racette, PE Tian, L AF Li, LH Heymsfield, GM Racette, PE Tian, L GP AMS TI Calibration of a 94 GHZ airborne cloud radar using measurements from the ocean surface SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RP Li, LH (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 204 EP 207 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300060 ER PT B AU Racette, P Heymsfield, GM Li, LH Tian, L Zenker, E AF Racette, P Heymsfield, GM Li, LH Tian, L Zenker, E GP AMS TI The cloud radar system SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Racette, P (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 555, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 237 EP 240 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300070 ER PT B AU Rickenbach, TM AF Rickenbach, TM GP AMS TI Nocturnal cloud systems and the diurnal cycle of rainfall in Amazonia SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rickenbach, TM (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 353 EP 356 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300104 ER PT B AU Tokay, A Wolff, KR Bashor, P Dursun, OK AF Tokay, A Wolff, KR Bashor, P Dursun, OK GP AMS TI On the measurement errors of the Joss-Waldvogel disdrometer SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID DROP SIZE DISTRIBUTION; RAINFALL C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tokay, A (reprint author), NASA, Goddard Space Flight Ctr, Code 912-1, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 403 EP 406 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300117 ER PT B AU Liao, L Meneghini, R Iguchi, T Detwiler, A AF Liao, L Meneghini, R Iguchi, T Detwiler, A GP AMS TI Validation of snow parameters as derived from dual-wavelength airborne radar SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Caelum Res Corp, Greenbelt, MD 20771 USA. RP Liao, L (reprint author), NASA, Goddard Space Flight Ctr, Caelum Res Corp, Code 975, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 411 EP 414 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300119 ER PT B AU Marks, DA Silberstein, DS Wolff, DB Amitai, E Pippitt, JL Lawrence, RJ AF Marks, DA Silberstein, DS Wolff, DB Amitai, E Pippitt, JL Lawrence, RJ GP AMS TI The TRMM ground validation effort at Nasa-GSFC: Validating surface rainfallestimates SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID RADAR C1 NASA, Goddard Space Flight Ctr, TRMM Satellite Validat Off, Greenbelt, MD 20771 USA. RP Marks, DA (reprint author), NASA, Goddard Space Flight Ctr, TRMM Satellite Validat Off, Code 912-1, Greenbelt, MD 20771 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 415 EP 418 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300120 ER PT B AU Wolff, DB Gerlach, J Marks, D Tokay, A Fisher, B Silberstein, D Wang, J AF Wolff, DB Gerlach, J Marks, D Tokay, A Fisher, B Silberstein, D Wang, J GP AMS TI On the characteristics of precipitation in the Florida Keys: The keys area precipitation project (KAPP) SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wolff, DB (reprint author), NASA, Goddard Space Flight Ctr, Code 912-1, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 437 EP 440 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300126 ER PT B AU Shie, CL Tao, WK Simpson, J AF Shie, CL Tao, WK Simpson, J GP AMS TI Simulated Kwajex convective systems using a 2D and 3D cloud resolving model and their comparisons with radar observations SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID EQUILIBRIUM STATES C1 NASA, Goddard Space Flight Ctr, Lab Atmospheres, Greenbelt, MD 20771 USA. RP Shie, CL (reprint author), NASA, Goddard Space Flight Ctr, Lab Atmospheres, Code 661, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 441 EP 444 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300127 ER PT B AU Tanelli, S Im, E Durden, SL Facheris, L AF Tanelli, S Im, E Durden, SL Facheris, L GP AMS TI Spectral processing techniques for measuring Doppler velocity of rainfall from a low earth orbiting satellite SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID RADAR C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tanelli, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-243, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 495 EP 498 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300143 ER PT B AU Grecu, M Olson, WS AF Grecu, M Olson, WS GP AMS TI Use of polarimetric radar observations in the evaluation of a TRMM combined radar-radiometer algorithm for estimation of precipitation profiles SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Grecu, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 508 EP 509 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300147 ER PT B AU Boccippio, DJ AF Boccippio, DJ GP AMS TI Archetypal trmm radar profiles identified through cluster analysis SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Boccippio, DJ (reprint author), NASA, George C Marshall Space Flight Ctr, SD-60, Huntsville, AL 35812 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 510 EP 513 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300148 ER PT B AU Atlas, D Ulbrich, CW Williams, CR AF Atlas, D Ulbrich, CW Williams, CR GP AMS TI Physical origin of a microburst seen by radar profiler SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID PRECIPITATION; SENSITIVITY; STORM C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Atlas, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 551 EP 554 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300159 ER PT B AU Hildebrand, PH Houser, P Schlosser, CA AF Hildebrand, PH Houser, P Schlosser, CA GP AMS TI Observing the global water cycle from space SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Hildebrand, PH (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 757 EP 760 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300219 ER PT B AU Amitai, E Nystuen, JA Liao, L AF Amitai, E Nystuen, JA Liao, L GP AMS TI Uniting space, ground and underwater measurements for better estimation of rain rates SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc ID RADAR C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Amitai, E (reprint author), NASA, Goddard Space Flight Ctr, Code 912-1, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 761 EP 764 PG 4 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300220 ER PT B AU Hildebrand, PH Hilliard, L Rincon, R Le Vine, D Mead, J AF Hildebrand, PH Hilliard, L Rincon, R Le Vine, D Mead, J GP AMS TI A radar/radiometer instrument for mapping soil moisture and ocean salinity SO 31ST CONFERENCE ON RADAR METEOROLOGY, VOLS 1 AND 2 LA English DT Proceedings Paper CT 31st Conference on Radar Meteorology CY AUG 06-12, 2003 CL Seattle, WA SP Amer Meteorol Soc C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hildebrand, PH (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2003 BP 826 EP 827 PG 2 WC Meteorology & Atmospheric Sciences; Physics, Applied SC Meteorology & Atmospheric Sciences; Physics GA BAT17 UT WOS:000223421300239 ER PT B AU Ponchak, GE Itotia, IK Drayton, RF AF Ponchak, GE Itotia, IK Drayton, RF GP EUMA EUMA TI Propagation characteristics of finite ground coplanar waveguide on Si substrates with porous Si and polyimide interface layers SO 33RD EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 33rd European Microwave Conference CY OCT 07-09, 2003 CL MUNICH, GERMANY SP European Microwave Assoc, IEEE, MTTS, APS AB Measured and modeled propagation characteristics of Finite Ground Coplanar (FGC) waveguide fabricated on a 15 Omega-cm Si substrate with a 23 gm thick, 68% porous Si layer and a 20 mum thick polyimide interface layer are presented for the first time. Attenuation and effective permittivity as function of the FGC geometry and the bias between the center conductor and the ground planes are presented. It is shown that the porous Si reduces the attenuation by 1 dB/cm compared to FGC lines with only polyimide interface layers, and the polyimide on porous silicon demonstrates negligible bias dependence. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. EM george.ponchak@ieee.org; drayton@ece.umn.edu NR 10 TC 4 Z9 4 U1 0 U2 1 PU HORIZON HOUSE PUBLICATIONS LTD PI LONDON PA 46 GILLINGHAM ST, LONDON SW1V 1HH, ENGLAND BN 1-58053-834-7 PY 2003 BP 45 EP 48 DI 10.1109/EUMA.2003.340822 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BY41G UT WOS:000189197200012 ER PT B AU Ponchak, GE Varaljay, NC Papapolymerou, J AF Ponchak, GE Varaljay, NC Papapolymerou, J GP EUMA EUMA TI Ka-band MEMS switches on CMOS grade silicon with a polyimide interface layer SO 33RD EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 33rd European Microwave Conference CY OCT 07-09, 2003 CL MUNICH, GERMANY SP European Microwave Assoc, IEEE, MTTS, APS AB For the first time, RF MEMS switches on CMOS grade Si with a polyimide interface layer are fabricated and characterized. At Ka-Band (36.6 GRz), an insertion loss of 0.52 dB and an isolation of 20 dB is obtained. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ponchak, GE (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd,MS 54-5, Cleveland, OH 44135 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU HORIZON HOUSE PUBLICATIONS LTD PI LONDON PA 46 GILLINGHAM ST, LONDON SW1V 1HH, ENGLAND BN 1-58053-834-7 PY 2003 BP 971 EP 974 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BY41G UT WOS:000189197200241 ER PT B AU Labelle, R Girard, R Arbery, G AF Labelle, R Girard, R Arbery, G GP EUMA EUMA TI A 94 GHz RF electronics subsystem for the CloudSat Cloud Profiling Radar SO 33RD EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 33rd European Microwave Conference CY OCT 07-09, 2003 CL MUNICH, GERMANY SP European Microwave Assoc, IEEE, MTTS, APS AB The CloudSat spacecraft, scheduled for launch in 2004, will carry the 94 GHz Cloud Profiling Radar (CPR) instrument. The design, assembly and test of the flight Radio Frequency Electronics Subsystem (RFES) for this instrument has been completed and is presented here. The RFES consists of an Upconverter (which includes an Exciter and two Drive Amplifiers (DA's)), a Receiver, and a Transmitter Calibrator assembly. Some key performance parameters of the RFES are as follows: dual 100 mW pulse-modulated drive outputs at 94 GHz, overall Receiver noise figure <5.0 dB, a highly stable W-band noise source to provide knowledge accuracy of Receiver gain of <0.4 dB over the 2 year mission life, and a W-band peak power detector to monitor the transmitter output power to within 0.5 dB over life. Some recent monolithic microwave integrated circuit (MMIC) designs were utilized which implement the DA's in 0.1 um GaAs high electron-mobility transistor (HEMT) technology and the Receiver low-noise amplifier (LNA) in 0.1 um InP HEMT technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Labelle, R (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 HORIZON HOUSE PUBLICATIONS LTD PI LONDON PA 46 GILLINGHAM ST, LONDON SW1V 1HH, ENGLAND BN 1-58053-834-7 PY 2003 BP 1139 EP 1142 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BY41G UT WOS:000189197200283 ER PT B AU Labelle, R AF Labelle, R GP EUMA EUMA TI A channelized 2(nd) IF/LO downconverter for the EOS Microwave Limb Sounder SO 33RD EUROPEAN MICROWAVE CONFERENCE, VOLS 1-3, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 33rd European Microwave Conference CY OCT 07-09, 2003 CL MUNICH, GERMANY SP European Microwave Assoc, IEEE, MTTS, APS AB The Earth Observing System (EOS) Microwave Limb Sounder (MLS) is scheduled for launch in 2004 on the EOS Aura spacecraft. The design, assembly and test of the flight 2(nd) Intermediate Frequency/Local Oscillator (2(nd) IF/LO) subsystem for this instrument has been completed and is presented here. The 2(nd) IF/LO subsystem consists of 5 separate microwave assemblies, 1 for each of the 5 millimeter wave radiometer front ends, providing a total of 33 separate IF channels. Some key requirements of the subsystem are as follows: provide frequency multiplexing of overlapping or closely spaced 1(st) IF channels while maintaining low ripple in the passbands; generate 18 different 2(nd) LO frequencies, in the range of 4-20 GHz, with low phase noise and a placement resolution of 400 KHz; down-convert the 1(st) IF's to a common 2(nd) IF frequency centered at 900 MHz; minimize cost and schedule by using common designs for the 5 different assemblies wherever possible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Labelle, R (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 HORIZON HOUSE PUBLICATIONS LTD PI LONDON PA 46 GILLINGHAM ST, LONDON SW1V 1HH, ENGLAND BN 1-58053-834-7 PY 2003 BP 1143 EP 1146 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA BY41G UT WOS:000189197200284 ER PT B AU Bowerman, PN Kirkham, H Fox, G Lancaster, P Lentz, S Kemski, KP Howe, BM AF Bowerman, PN Kirkham, H Fox, G Lancaster, P Lentz, S Kemski, KP Howe, BM GP IEEE IEEE TI Engineering reliability for the NEPTUNE observatory SO 3RD INTERNATIONAL WORKSHOP ON SCIENTIFIC USE OF SUBMARINE CABLES AND RELATED TECHNOLOGY, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Workshop on Scientific Use Submarine Cables and Related Technologies CY JUN 25-27, 2003 CL UNIV TOKYO, KOMABA CAMPUS, TOKYO, JAPAN SP IEEE Ocean Engn Soc Japan Chapter, Univ Tokyo, Earthquake Res Inst,, Univ Tokyo, Inst Ind Sci, Univ Tokyo, Ocean Res Inst, Japan Marine Sci & Technol Ctr, IEEE Ocean Engn Soc, Comm Sci Submarine Cables Japan, Comm Sci Submarine Cabled United State HO UNIV TOKYO, KOMABA CAMPUS DE mission assurance; reliability; quality; testing; NEPTUNE AB This paper reviews aspects of Engineering for Reliability of the proposed NEPTUNE observatory. NEPTUNE has an equipment life requirement of around 30 years, and (because of the local weather) presents limited opportunity for repair. It is necessary to use methods and parts that assure the system is sufficiently reliable and maintainable. Among the factors that influence construction are appropriate parts selection criteria, quality assurance inspections, thorough testing of hardware, understanding and accommodating the shock environment of deployment and maintenance cycles, assuring that there will not be material compatibility issues, minimizing the risk that software will result in system failure, analyzing the hardware designs to assure that they should still work correctly after 30 years and that failures do not propagate, and tracking all anomalies to make sure they are appropriately resolved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bowerman, PN (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. OI Howe, Bruce/0000-0001-5711-5253 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 0-7803-7775-3 PY 2003 BP 57 EP 62 PG 6 WC Engineering, Ocean; Geosciences, Multidisciplinary; Instruments & Instrumentation SC Engineering; Geology; Instruments & Instrumentation GA BX85Q UT WOS:000186634900011 ER PT B AU Kirkham, H Lancaster, P Liu, CC El-Sharkawi, M Howe, BM AF Kirkham, H Lancaster, P Liu, CC El-Sharkawi, M Howe, BM GP IEEE IEEE TI The NEPTUNE power system: design from fundamentals SO 3RD INTERNATIONAL WORKSHOP ON SCIENTIFIC USE OF SUBMARINE CABLES AND RELATED TECHNOLOGY, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Workshop on Scientific Use Submarine Cables and Related Technologies CY JUN 25-27, 2003 CL UNIV TOKYO, KOMABA CAMPUS, TOKYO, JAPAN SP IEEE Ocean Engn Soc Japan Chapter, Univ Tokyo, Earthquake Res Inst,, Univ Tokyo, Inst Ind Sci, Univ Tokyo, Ocean Res Inst, Japan Marine Sci & Technol Ctr, IEEE Ocean Engn Soc, Comm Sci Submarine Cables Japan, Comm Sci Submarine Cabled United State HO UNIV TOKYO, KOMABA CAMPUS DE power delivery; NEPTUNE; Mission Assurance AB This paper describes the process and recounts the decisions that have been made in the design of the NEPTUNE power system. The design process has consisted of a number of top-level decisions based on trade-off studies, followed by a number of more detailed developments based on fundamental considerations of the system needs. The system will use a parallel 10-kV dc scheme to deliver power at 400 V to the user. Altogether, around 100 kW can be delivered to the load distributed along the underwater cable, and up to 10 kW can be obtained at any one science node. In the design process, several commonplace solutions of power engineering have been re-examined and abandoned. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Kirkham, H (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. OI Howe, Bruce/0000-0001-5711-5253 NR 6 TC 0 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7775-3 PY 2003 BP 301 EP 306 PG 6 WC Engineering, Ocean; Geosciences, Multidisciplinary; Instruments & Instrumentation SC Engineering; Geology; Instruments & Instrumentation GA BX85Q UT WOS:000186634900065 ER PT B AU Zelinski, S Koo, TJ Sastry, S AF Zelinski, S Koo, TJ Sastry, S GP IEEE IEEE TI Hybrid system design for formations autonomous vehicles SO 42ND IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-6, PROCEEDINGS LA English DT Proceedings Paper CT 42nd IEEE Conference on Decision and Control CY DEC 09-12, 2003 CL Maui, HI SP IEEE, SIAM, Control Syst Soc, SICE, Informs, Honeywell Lab, Natl Instruments, XEROX, MathWorks AB Cooperative control of multiple unmanned aerial vehicles (UAVs) poses significant theoretical and technical challenges. Recent advances in sensing, communication and computation enable the conduct of cooperative multiple-UAV missions deemed impossible in the recent past. We are interested in solving the Formation Reconfiguration Planning (FRP) problem which is focused on determining a nominal state and input trajectory for each vehicle such that the group can start from the given initial configuration and reach its given final configuration at the specified time while satisfying a set of given inter- and intra- vehicle constraints. Each solution of a FRP problem represents a distinct reconfiguration mode. When coupled with formation keeping modes, they can form a hybrid automaton of formation maneuvers in which a transition from one formation maneuver to another formation maneuver is governed by a finite automaton. This paper focuses on the implementation of the optimized hybrid system approach to formation reconfiguration. for a group of 1 real and 3 virtual UAVs. Experimental results performed in the Richmond Field Station by using a helicopter-based Berkeley Aerial Robot are presented. C1 NASA, Ames Res Ctr, Aerosp Operat Modelling, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Aerosp Operat Modelling, Moffett Field, CA 94035 USA. EM szelinski@mail.arc.nasa.gov; john.koo@vanderbilt.edu; sastry@eecs.berkeley.edu NR 10 TC 2 Z9 2 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7924-1 PY 2003 BP 1 EP 6 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BY66S UT WOS:000189434100001 ER PT B AU Mukhopadhyay, S AF Mukhopadhyay, S GP IEEE IEEE TI Abstract spatial hybrid systems for image processing SO 42ND IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-6, PROCEEDINGS LA English DT Proceedings Paper CT 42nd IEEE Conference on Decision and Control CY DEC 09-12, 2003 CL Maui, HI SP IEEE, SIAM, Control Syst Soc, SICE, Informs, Honeywell Lab, Natl Instruments, XEROX, MathWorks AB Model-based design and development has become a popular paradigm for developing embedded systems. Many modern embedded systems have components that are dedicated to capturing and processing images for object recognition. Examples of such systems include autonomous robots, spacecrafts and security devices. Such image processing functionalities are performed by software that involve nonlinear operations. Hybrid systems are models of nonlinear systems that involve the interaction of continuous and discrete dynamics. They have been used to solve problems in diverse domains ranging from operations research, design of embedded systems to the design and analysis of biological systems. In particular, they have been used as models for model-based design, development and analysis of embedded and biological systems. We introduce a new version of hybrid systems called the abstract spatial hybrid systems (machines). We describe how such systems can be used as models for image processing tasks like image registration. C1 W Virginia Univ, NASA, Software Res Lab, Morgantown, WV 26506 USA. RP Mukhopadhyay, S (reprint author), W Virginia Univ, NASA, Software Res Lab, Morgantown, WV 26506 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 BN 0-7803-7924-1 PY 2003 BP 342 EP 343 PG 2 WC Automation & Control Systems SC Automation & Control Systems GA BY66S UT WOS:000189434100059 ER PT B AU Akpan, E AF Akpan, E GP IEEE IEEE TI Selection of initial gain for optimal compensators SO 42ND IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-6, PROCEEDINGS LA English DT Proceedings Paper CT 42nd IEEE Conference on Decision and Control CY DEC 09-12, 2003 CL Maui, HI SP IEEE, SIAM, Control Syst Soc, SICE, Informs, Honeywell Lab, Natl Instruments, XEROX, MathWorks DE output feedback system; multivariabe system; compensators; Hurwitz matrix ID OUTPUT-FEEDBACK AB A technique for selecting initial gain such that a compensated feedback system is asymptotically stable is proposed. The problem is in two parts namely modeling and initial gain selection. The initial gain so obtained is used as a starting value for controller optimization. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Akpan, E (reprint author), NASA, Goddard Space Flight Ctr, Code 544, 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 BN 0-7803-7924-1 PY 2003 BP 4968 EP 4972 DI 10.1109/CDC.2003.1272413 PG 5 WC Automation & Control Systems SC Automation & Control Systems GA BY66S UT WOS:000189434100852 ER PT B AU Shaw, HY Sherif, JS Girard, M Perun, V AF Shaw, HY Sherif, JS Girard, M Perun, V BE Callaos, N DiSciullo, AM Ohta, T Liu, TK TI Software management and implementation plan for the Microwave Limb Sounder (MLS) carried on a NASA satellite SO 7TH WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL I, PROCEEDINGS: INFORMATION SYSTEMS, TECHNOLOGIES AND APPLICATIONS LA English DT Proceedings Paper CT 7th World Multiconference on Systemics, Cybernetics and Informatics CY JUL 27-30, 2003 CL ORLANDO, FL SP Int Inst Informat & System DE software management plan; Microwave Limb Sounder; work implementation plan; flight development phases AB This paper presents a Software Management and Implementation Plan (SMIP) for managing and controlling the development of the Microwave Limb Sounder (MLS) instrument software, and the Instrument Ground Support Equipment (IGSE) software. The paper is intended to be a combination of the Software Management Plan (SMP) and the Work Implementation Plan (WIP). It describes the management approach to developing the instrument software and the IGSE software which is used to test the instrument and its software. This includes the flight development phases, flight software activities, life cycle, deliverables, and other software development process issues such as configuration management practices, software assurance activities, risk management and metrics reporting. The project was completed at the Jet Propulsion Laboratory (JPL). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shaw, HY (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU INT INST INFORMATICS & SYSTEMICS PI ORLANDO PA 14269 LORD BARCLAY DR, ORLANDO, FL 32837 USA BN 980-6560-01-9 PY 2003 BP 311 EP 315 PG 5 WC Computer Science, Information Systems SC Computer Science GA BY46R UT WOS:000189328300057 ER PT B AU Maluf, DA Gurram, MM Dorais, GA Tran, P AF Maluf, DA Gurram, MM Dorais, GA Tran, P BE Callaos, N Chien, BC Dong, J Li, W TI Active sensor vision sensing for spacecraft mobile robot navigation SO 7TH WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL II, PROCEEDINGS: COMPUTER SCIENCE AND ENGINEERING LA English DT Proceedings Paper CT 7th World Multiconference on Systemics, Cybernetics and Informatics CY JUL 27-30, 2003 CL ORLANDO, FL SP Int Inst Informat & System DE laser-camera navigation system; spacecraft mobile robot; personal satellite assistant; laser projection data; camera registration; field of view; focal length; normalization; reference frame transformation; reference frame matrices; rotation matrices AB The advent of spacecraft mobile robots-free-flying sensor platforms and communications devices intended to accompany astronauts or remotely operate on space missions inside and outside of spacecraft-has demanded the development of a simple and effective navigation. One such system under exploration involves the use of a laser-camera arrangement to predict relative positioning of the mobile robot. By projecting laser beams from the robot, a 3D reference frame can be introduced. Thus, as the robot shifts in position, the position reference frame produced by the laser images is correspondingly altered. Using normalization and camera registration techniques presented in this paper, the relative translation and rotation of the robot in 3D are determined from these reference frame transformations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 269-2, Moffett Field, CA 94035 USA. EM dmaluf@arc.nasa.gov; mgurram@email.arc.nasa.gov; gdorais@arc.nasa.gov; pbtran@mail.arc.nasa.gov NR 10 TC 0 Z9 0 U1 0 U2 0 PU INT INST INFORMATICS & SYSTEMICS PI ORLANDO PA 14269 LORD BARCLAY DR, ORLANDO, FL 32837 USA BN 980-6560-01-9 PY 2003 BP 24 EP 29 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA BY46S UT WOS:000189328700005 ER PT B AU Ippolito, C Plice, L Pisanich, G AF Ippolito, C Plice, L Pisanich, G BE Callaos, N Huang, T Jiang, JP Wu, T TI Holarchical systems and emotional holons: biologically-inspired system designs for control of autonomous aerial vehicles SO 7TH WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL XI, PROCEEDINGS: COMMUNICATION, NETWORK AND CONTROL SYSTEMS, TECHNOLOGIES AND APPLICATIONS: II LA English DT Proceedings Paper CT 7th World Multiconference on Systemics, Cybernetics and Informatics CY JUL 27-30, 2003 CL ORLANDO, FL SP Int Inst Informat & System DE holarchy; biologically inspired; emotional UAV flight control AB The BEES (Bio-inspired Engineering for Exploration Systems) for Mars project at NASA Ames Research Center has the goal of developing bio-inspired flight control strategies to enable aerial explorers for Mars scientific investigations. This paper presents a summary of our ongoing research into biologically inspired system designs for control of unmanned autonomous aerial vehicle communities for Mars exploration. First, we present cooperative design considerations for robotic explorers based on the holarchical nature of biological systems and communities. Second, an outline of an architecture for cognitive decision making and control of individual robotic explorers is presented, modeled after the emotional nervous system of cognitive biological systems. C1 QSS Grp Inc, NASA Computat Sci Div, NASA Ames Res Ctr, Moffett Field, CA USA. RP QSS Grp Inc, NASA Computat Sci Div, NASA Ames Res Ctr, Moffett Field, CA USA. NR 27 TC 0 Z9 0 U1 0 U2 1 PU INT INST INFORMATICS & SYSTEMICS PI ORLANDO PA 14269 LORD BARCLAY DR, ORLANDO, FL 32837 USA BN 980-6560-01-9 PY 2003 BP 24 EP 31 PG 8 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Telecommunications SC Automation & Control Systems; Computer Science; Engineering; Telecommunications GA BY50T UT WOS:000189394900007 ER PT B AU Crichton, D Srivastava, S Johnsey, D AF Crichton, D Srivastava, S Johnsey, D BE Callaos, N Farsi, D EshaghianWilner, M Hanratty, T Rishe, N TI A virtual Bioinformatics knowledge environment for early cancer detection SO 7TH WORLD MULTICONFERENCE ON SYSTEMICS, CYBERNETICS AND INFORMATICS, VOL XVI, PROCEEDINGS: SYSTEMICS AND INFORMATION SYSTEMS, TECHNOLOGIES AND APPLICATION LA English DT Proceedings Paper CT 7th World Multiconference on Systemics, Cybernetics and Informatics CY JUL 27-30, 2003 CL ORLANDO, FL SP Int Inst Informat & System DE knowledge system; distributed systems; data management; bioinformatics AB Discovery of disease biomarkers for cancer is a leading focus of early detection. The National Cancer Institute created a network of collaborating institutions focused on the discovery and validation of cancer biomarkers called the Early Detection Research Network (EDRN). Informatics plays a key role in enabling a virtual knowledge environment that provides scientists real time access to distributed data sets located at research institutions across the nation. The distributed and heterogeneous nature of the collaboration makes data sharing across institutions very difficult. EDRN has developed a comprehensive informatics effort focused on developing a national infrastructure enabling seamless access, sharing and discovery of science data resources across all EDRN sites. This paper will discuss the EDRN knowledge system architecture, its objectives and its accomplishments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Crichton, 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 INT INST INFORMATICS & SYSTEMICS PI ORLANDO PA 14269 LORD BARCLAY DR, ORLANDO, FL 32837 USA BN 980-6560-01-9 PY 2003 BP 209 EP 213 PG 5 WC Computer Science, Information Systems SC Computer Science GA BY51D UT WOS:000189396600039 ER PT S AU Artho, C Drusinksy, D Goldberg, A Havelund, K Lowry, M Pasareanu, C Rosu, G Visser, W AF Artho, C Drusinksy, D Goldberg, A Havelund, K Lowry, M Pasareanu, C Rosu, G Visser, W BE Borger, E Gargantini, A Riccobene, E TI Experiments with test case generation and runtime analysis SO ABSTRACT STATE MACHINES 2003: ADVANCES IN THEORY AND PRACTICE, PROCEEDINGS SE Lecture Notes in Computer Science LA English DT Article; Proceedings Paper CT 10th International Workshop on Abstract State Machines CY MAR 03-07, 2003 CL TAORMINA, ITALY SP Microsoft Res, Univ Pisa, Univ Catania, Proteo SpA AB Software testing is typically an ad hoc process where human testers manually write many test inputs and expected test results, perhaps automating their execution in a regression suite. This process is cumbersome and costly. This paper reports preliminary results on an approach to further automate this process. The approach consists of combining automated test case generation based on systematically exploring the program's input domain, with runtime analysis, where execution traces are monitored and verified against temporal logic specifications, or analyzed using advanced algorithms for detecting concurrency errors such as data races and deadlocks. The approach suggests to generate specifications dynamically per input instance rather than statically once-and-for-all. The paper describes experiments with variants of this approach in the context of two examples, a planetary rover controller and a space craft fault protection system. C1 ETH, Inst Comp Syst, CH-8092 Zurich, Switzerland. USN, Postgrad Sch, Monterey, CA USA. Time Rover Inc, Cupertino, CA USA. NASA, Ames Res Ctr, Kestrel Technol, Moffett Field, CA 94035 USA. Univ Illinois, Dept Comp Sci, Urbana, IL 61801 USA. NASA, Ames Res Ctr, RIACS, Moffett Field, CA 94035 USA. RP ETH, Inst Comp Syst, CH-8092 Zurich, Switzerland. NR 24 TC 16 Z9 16 U1 1 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-00624-9 J9 LECT NOTES COMPUT SC PY 2003 VL 2589 BP 87 EP 107 PG 21 WC Computer Science, Theory & Methods SC Computer Science GA BW63J UT WOS:000182655500005 ER PT J AU Mankins, JC AF Mankins, JC TI At the threshold: emerging opportunities for expanding commercial and governmental space operations in the new century - The 1997 KRAFT EHRICKE Lecture for the 27th Symposium on Economics in Space Operations of the IAA SO ACTA ASTRONAUTICA LA English DT Article AB We stand at the threshold of a new era in space operations in which a host of potentially profound changes will occur in space systems concepts and technologies. Many of the space systems in use today were originally created in the mid- to late-1960s, based on technologies either already existing or then under development. These concepts-including satellites, launchers and piloted systems-have served well for government and commercial missions during the decades since that era. They will continue to serve-and serve well-as we enter the first decade of the next century. However, in this era of restraint in government spending on civilian space and dramatic growth in investments in existing space commercial ventures, new, breakthrough systems concepts that drive down costs are critically needed. Fortunately these new concepts appear to be at hand. Building on the research foundation of the past 20 years, an array of new technologies are emerging which may make possible highly innovative advanced systems concepts. These technologies include long-lived high-efficiency chemical propulsion, affordable megawatt-class space power systems, advanced electromagnetic systems, breakthrough materials, "brilliant" space machines, robust artificial intelligences onboard and on the ground, low-cost utilization of local resources, and others. Moreover, many of these technologies appear common to both new space industries and very affordable future government missions. Forerunners of this new era can be seen today in the systems of large telecommunications satellite constellations such as the Iridium venture and in the technologies of the reusable launch vehicle program. Driving down the cost of space access will be the linchpin for this prospective future. In addition, during the coming decade, a wide range of civilian government space investments will likely be focused on vitally-needed research and development. Our choices now are exceptionally important and must be made wisely. We stand at the threshold. Across a broad technological frontier, diverse opportunities are emerging that might well make possible the creation of revolutionary systems concepts and a dramatic expansion of new space industries, while also enabling bold, but affordable missions of human exploration beyond Earth orbit. Published by Elsevier Science Ltd. C1 NASA, Adv Projects Off, Washington, DC 20546 USA. RP Mankins, JC (reprint author), NASA, Adv Projects Off, 300 E St SW, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN PY 2003 VL 52 IS 1 BP 41 EP 48 AR PII S0094-5765(02)00116-9 DI 10.1016/S0094-5765(02)00116-9 PG 8 WC Engineering, Aerospace SC Engineering GA 624GP UT WOS:000179752200005 ER PT J AU Atkins, KL Martin, BD Vellinga, JM Price, RA AF Atkins, KL Martin, BD Vellinga, JM Price, RA TI STARDUST: implementing a new manage-to-budget paradigm SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB STARDUST is the Discovery Program's fourth mission. It follows Lunar Prospector, Mars Pathfinder and the Near Earth Asteroid Rendezvous (NEAR) mission. Launched on February 7, 1999, the STARDUST flight system will collect comet samples during a 6 km/s flyby of Comet Wild 2 on New Year's day, 2004, and return the samples to Earth in January 2006. Enroute to the comet, STARDUST will also attempt to collect samples of interstellar dust. The Jet Propulsion Laboratory (JPL) provides project and mission management with Lockheed Martin Astronautics (LMA) as the industrial partner for the flight and ground systems. LMA made strong use of developments in the Mars Global Surveyor (MGS) and the Mars Surveyor '98 projects preceding STARDUST. Under the stringent cost-caps of the Discovery Program, the STARDUST development was completed on time with nearly $2M remaining reserves to reprogramming into the flight phase. The STARDUST management team aggressively worked to achieve this control through the use of total quality management (TQM) and reengineering principles, and commercially available software tools. The approach was to develop project-to-project interfaces exploiting parts stores and common procurements, shared staffing and shared facilities. Inheriting parts, hardware, software and designs leveraged dollars efficiently to accelerate the development, while staying inside a constrained budget. Additionally, to achieve the required level of time efficiency and budget control, a new level of communications and data handling (read excellent Management Information System [MIS]) is mandatory. Finessing the rigidity of traditional Performance Management (or Measurement) Systems (PMS) and institutional/corporate cultures requires a new way thinking and a cheerleader aggressiveness. STARDUST organized toward the Integrated Product Development Team (IPDT) concept as a central feature. This was matrixed into a dedicated Product Development Office (PDO) at LMA. The PDO served the leveraging goal by serving two projects, STARDUST and Mars Surveyor '98. It avoided duplicate project-unique personnel structures and offered cost benefits to each project. This paper provides details and example metrics characterizing the aggressive application of the design-to-cost paradigm and implementation by the STARDUST management team to achieve success under the Discovery Program budget constraints. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91011 USA. Martin Consulting Grp LLC, Stevenson Ranch, CA 91381 USA. Lockheed Martin Astronaut, Denver, CO USA. RP Atkins, KL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91011 USA. NR 0 TC 4 Z9 4 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 87 EP 97 AR PII S0094-5765(02)00142-X DI 10.1016/S0094-5765(02)00142-X PG 11 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700003 ER PT J AU Blume, WH AF Blume, WH TI Deep Impact: mission design approach for a new Discovery mission SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Deep Impact is a new NASA Discovery mission to launch in early 2004. This paper discusses the mission design strategies for this unique mission, which will target a 500-kg impactor into a comet nucleus at a speed of 10 km/s, in order to reveal the subsurface materials and structure. Trajectory designs are shown for reaching comet P/Tempel 1 near perihelion at its 2005 apparition and for the approach and flyby trajectories of the flyby spacecraft, which carries the impactor up to 24 h before impact. The mission and encounter timelines are discussed for the events of the cruise, approach, and encounter phases of the mission, including the strategies for observing the impact and returning the data to Earth. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Blume, WH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 5 Z9 5 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 105 EP 110 AR PII S0094-5765(02)00144-3 DI 10.1016/S0094-5765(02)00144-3 PG 6 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700005 ER PT J AU Wolf, AA AF Wolf, AA TI Mainbelt asteroid reconnaisance and sample return using solar electric propulsion SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Reconnaisance of asteroids has thus far been accomplished on a limited scale. The scientific community has expressed interest in conducting long-term reconnaisance of multiple mainbelt asteroids and returning a sample from a mainbelt asteroid, with Ceres and Vesta the targets of greatest interest. This work presents results of preliminary feasibility studies of these missions. Since propellant requirements are prohibitively large with chemical propulsion, solar electric propulsion was assumed here. Multiple opportunities for Ceres/Vesta reconnaisance missions and Vesta sample returns were found which appear to be feasible in the next decade. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Inner Planets Miss Anal Grp, Pasadena, CA 91109 USA. RP Wolf, AA (reprint author), CALTECH, Jet Prop Lab, Inner Planets Miss Anal Grp, MS 301-140H, Pasadena, CA 91109 USA. NR 8 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 133 EP 141 AR PII S0094-5765(02)00149-2 DI 10.1016/S0094-5765(02)00149-2 PG 9 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700009 ER PT J AU Klaasen, KP Greeley, R AF Klaasen, KP Greeley, R TI VEVA Discovery mission to Venus: exploration of volcanoes and atmosphere SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Venus Exploration of Volcanoes and Atmosphere (VEVA) is a potential Discovery mission. It will provide a multidisciplinary investigation of the atmosphere and surface of Venus by returning the first-ever aerial photography of the surface and definitive, in situ determination of its atmospheric composition in the lower scale height. VEVA involves delivering an entry vehicle to Venus housing a payload consisting of an instrumented atmospheric sonde and a balloon-gondola system. After entry, the atmospheric sonde is released to fall to the surface, and the balloon package inflates, which arrests its descent at a 60-km float height. The balloon carries an instrumented gondola with battery power for 7 days as it circles Venus. The gondola carries four small imaging sondes for release and descent to the surface at different times during the 7-day mission. Data from the sondes are radioed to the gondola for relay to Earth. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. RP Klaasen, KP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 3 Z9 3 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 151 EP 158 AR PII S0094-5765(02)00151-0 DI 10.1016/S0094-5765(02)00151-0 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700011 ER PT J AU Kerzhanovich, VV Crisp, D Preston, RA Esposito, LW Ingersoll, AP Young, RE Blamont, JE Linkin, VV AF Kerzhanovich, VV Crisp, D Preston, RA Esposito, LW Ingersoll, AP Young, RE Blamont, JE Linkin, VV TI Venus stratospheric sounder: first in situ measurements in upper cloud region SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB In spite of intensive ground-based and space observations, many major questions about the Venus are still unanswered. Among them are the nature, pattern and evolution of the atmospheric circulation in the troposphere and stratosphere, the nature and distribution of the UV-absorber, and the structure and composition of the stratospheric clouds. There is no accurate data on the vertical structure of the lowest 12 km. The stratosphere, with exception of the probes' accelerometer data, has been essentially unexplored with in situ measurements. It is also unknown if any noticeable changes in the structure and circulation of the atmosphere have occurred since the last VEGA mission in 1985. Future missions, such as the Venus Surface Sample Return Mission, require improved knowledge of the Venus atmospheric environment where these missions need to operate with much better accuracy and less risk than before. The proposed Venus Statospheric Sounder Mission could serve as a low-cost effective precursor to this more ambitious project. The main element of the mission is the balloon-borne sonde that will ascend to 80-82 km altitude after aerial deployment and inflation at 55-60 km and will transmit data direct to Earth on the way through the atmosphere. The basic set of instruments may include pressure and temperature sensors, nephelometer, and sensors to measure the chemical composition of clouds. Differential Very Long Base Interferometry tracking of the balloon will give an accurate wind profile of the atmosphere of Venus. It will be the first mission that will provide data on the Venus stratosphere with high vertical resolution. The mission is lightweight and can be delivered on the Micromission Probe Vehicle. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Boulder, CO 80309 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CNES, Paris, France. Space Res Inst, Moscow, Russia. RP Kerzhanovich, VV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 3 Z9 3 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 159 EP 164 AR PII S0094-5765(02)00152-2 DI 10.1016/S0094-5765(02)00152-2 PG 6 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700012 ER PT J AU Sweetser, T Peterson, C Nilsen, E Gershman, B AF Sweetser, T Peterson, C Nilsen, E Gershman, B TI Venus sample return missions - a range of science, a range of costs SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Venus sample return missions have been studied occasionally for the last 40 years, but only recently has technology advanced to the point where this kind of mission has been realistic. At the same time, however, cost constraints have become more important. NASA recently has been studying a set of Venus sample return missions which span a range of scientific goals and which have a corresponding range of costs. The simplest sample return from Venus is to fly through the upper atmosphere and return some of the gas to Earth. This turns out to be possible using a free-return ballistic trajectory. The gas sample would be captured at hypersonic velocities and would be greatly affected by the process, but we could still determine isotopic ratios to very high precision on the ground and may be able to determine elemental ratios. This mission is roughly a moderate Discovery class mission reminiscent of Stardust. The next level of sample return mission would be another atmosphere sample mission, but would involve much more benign sampling conditions. At Venus arrival the spacecraft would be aerocaptured into orbit at Venus and aerobrake to a circular orbit. A sample-gathering vehicle would enter the atmosphere and slow significantly, allowing capture of a well-mixed atmosphere sample which preserves chemical composition. An on-board rocket would then return the sample to Venus orbit, where the orbiting spacecraft would retrieve it and bring it back to Earth. This mission is somewhat beyond Discovery class, though not outrageously so. The most difficult level of sample return mission would be a sample from the surface of Venus. The surface of Venus is the hottest surface and has the greatest atmospheric pressure and density of any known surface in the solar system. This presents great challenges to both the sampling lander and to the Venus ascent vehicle (VAV) which must return the sample to orbit. Indeed, it is impossible in any practical sense to use a rocket ascent vehicle directly from the surface; instead; a balloon is used to lift the VAV with the sample to an altitude above the clouds where both temperature and pressure are not unlike Earth's, whence the rocket fires to orbit the sample. This mission is substantially more difficult and costly than the atmosphere sampling missions described above, but would allow direct examination of Venus to answer questions about solar system formation and Venus's evolution since then. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sweetser, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 3 Z9 3 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 165 EP 172 AR PII S0094-5765(02)00153-4 DI 10.1016/S0094-5765(02)00153-4 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700013 ER PT J AU Clark, PE Curtis, SA Marr, G Reuter, D McKenna-Lawlor, S AF Clark, PE Curtis, SA Marr, G Reuter, D McKenna-Lawlor, S TI LUGH/Mercury express: a proposed multi-platform flyby mission to Mercury SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB LUGH is a fast (1 year), low cost, high heritage, high data return (100 Gbits), 3-platform, dual-flyby pathfinder mission to Mercury. It is designed to investigate the planet's interior structure and magnetic field to 3rd order; provide imaging/mapping and bulk composition of the entire surface, determine the composition of the exosphere, and model the 3D structure, composition, key boundaries, wave/particle interactions, dynamics and particle sources/sinks of the magnetosphere. These objectives are met through the hitherto unprecedented means of flying a well-instrumented spacecraft with equatorial periapses supported by two polar nanoprobes, thereby substantially expanding the measurement capability of a single spacecraft. Measurements at Mercury which can be uniquely provided by LUGH include a comprehensive field, particle, and plasma dataset, including high speed, energetic neutral atom spectrometry to monitor the magnetospheric/solar wind interaction. LUGH would also allow more complete interpretation of planned orbiter data. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Space Technol Ireland Ltd, Maynooth NUI, Maynooth, Kildare, Ireland. RP Clark, PE (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 7 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 181 EP 188 AR PII S0094-5765(02)00155-8 DI 10.1016/S0094-5765(02)00155-8 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700015 ER PT J AU Hastrup, RC Bell, DJ Cesarone, RJ Edwards, CD Ely, TA Guinn, JR Rosell, SN Srinivasan, JM Townes, SA AF Hastrup, RC Bell, DJ Cesarone, RJ Edwards, CD Ely, TA Guinn, JR Rosell, SN Srinivasan, JM Townes, SA TI Mars network for enabling low-cost missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Mars is the first planet where significant steps are being taken to establish a "virtual presence throughout the solar system"-one of NASA's strategic goals. Preparations are under way to begin implementation of an evolving Mars Network of satellites to meet the future communications and navigation challenges of the ongoing international Mars exploration campaign. The Mars Network concept is to deploy two classes of satellites. The first class is very low-cost MicroSats, launched piggyback on Ariane 5, for deployment in 800-km circular orbits in a variety of planes for frequent global contacts. From their low orbits, the MicroSats provide highly efficient relay communication links for small, energy constrained landers, and their orbital motion provides strong navigation signatures. The second, larger class of Mars areostationary satellites (MARSats) are deployed in 17,000-km orbits with 1-sol periods, as required, to support very high bandwidth users. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hastrup, RC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 17 Z9 19 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 227 EP 235 AR PII S0094-5765(02)00161-3 DI 10.1016/S0094-5765(02)00161-3 PG 9 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700021 ER PT J AU Jonaitis, J Kubitschek, J Howard, J Reitsema, H Smith, E Lisman, D Spilker, T Garner, G AF Jonaitis, J Kubitschek, J Howard, J Reitsema, H Smith, E Lisman, D Spilker, T Garner, G TI A solar powered spacecraft for the INSIDE Jupiter mission SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB The Interior Structure and Internal Dynamical Evolution (INSIDE) Jupiter mission was proposed and accepted for Step 2 conceptual design as part of Discovery 98. It will achieve fundamental new advances in our understanding of Jupiter and extra-solar planets during its 15-month mission at Jupiter with its four science investigations. It will be the first solar-powered, Discovery-class mission to the outer planets. A solar-powered mission to Jupiter poses several challenges for the spacecraft designer including a harsh radiation environment, limited launch mass, extreme thermal conditions and long-cruise duration. The INSIDE Jupiter team has resolved these challenges at minimal cost through the use of recently available mission enabling technologies, efficient trajectories and orbit designs, simple operations, and innovative technical design features. (C) 2002 Published by Elsevier Science Ltd. C1 Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jonaitis, J (reprint author), Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 237 EP 244 AR PII S0094-5765(02)00162-5 DI 10.1016/S0094-5765(02)00162-5 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700022 ER PT J AU Esper, J Panetta, P Coronado, P Concha, M Martinez, T Scott, S Soldner, J AF Esper, J Panetta, P Coronado, P Concha, M Martinez, T Scott, S Soldner, J TI VOLCAN: a mission to explore Jupiter's volcanic moon Io SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB This paper presents a near-term implementation solution to the exploration of Jupiter's volcanic moon Io. We first start by providing the scientific rationale for a mission to Io, and its alignment within NASA's strategic plan. The instruments selected represent a careful balance between focused scientific goals, and programmatic restrictions imposed by a Discovery-class mission. We discuss the difficulties inherent in visiting distant Io, including those to be expected from its extreme radiation environment. The mission design incorporates a trajectory in line with overall cost constraints, including launch vehicle limitations. Finally, the spacecraft design incorporates the use of solar arrays and chemical propulsion as a demonstration of the feasibility of executing an outer planet mission with state-of-the-art technology. In summary, we present the scientific rationale and demonstrate both the feasibility and limitations of a Discovery-class mission to Io, relying exclusively on existing or near-term developing technologies. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Swales Aerosp, Beltsville, MD 20705 USA. SAIC, Washington, DC 20024 USA. RP Esper, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 245 EP 251 AR PII S0094-5765(02)00163-7 DI 10.1016/S0094-5765(02)00163-7 PG 7 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700023 ER PT J AU Gershman, R Nilsen, E Oberto, R AF Gershman, R Nilsen, E Oberto, R TI Europa Lander SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB A Europa Lander mission has been assigned high priority for the post-2005 time frame in NASA's Space Science Enterprise Strategic Plan. Europa is one of the most scientifically interesting objects in the solar system because of the strong possibility that a liquid water ocean exists underneath its ice-covered surface. The primary scientific goals of the proposed Europa Lander mission are to characterize the surface material from a recent outflow and look for evidence of pre-biotic and possibly biotic chemistry. The baseline mission concept involves landing a single spacecraft on the surface of Europa with the capability to acquire samples of material, perform detailed chemical analysis of the samples, and transmit the results to Earth. This paper provides a discussion of the benefits and status of the key spacecraft and instrument technologies needed to accomplish the science objectives. Also described are variations on the baseline concept including the addition of small auxiliary probes and an experimental ice penetration probe. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gershman, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 7 Z9 7 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 253 EP 258 AR PII S0094-5765(02)00164-9 DI 10.1016/S0094-5765(02)00164-9 PG 6 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700024 ER PT J AU Spilker, TR AF Spilker, TR TI Saturn Ring Observer SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Scientists studying planetary ring systems and planetary system formation have long wanted close-up (a few km) observations of Saturn's rings to answer fundamental questions about ring particle characteristics and behavior. But missions to implement these observations involve post-approach DeltaV requirements greater than 10 km/s, so past designs have called upon Nuclear Electric Propulsion-an untenable position in the current programmatic climate. A unique new mission design uses carefully designed aerocapture to decrease the DeltaV requirement to as little as 3.5 km/s, a difficult but not impossible feat for high-performance chemical propulsion systems. Propulsion costs dominate cost estimates for the Saturn Ping Observer mission. Driving down propulsion costs is an important facet of the strategic technology program, one that would provide cost benefits to many other missions. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Spilker, TR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 259 EP 265 AR PII S0094-5765(02)00165-0 DI 10.1016/S0094-5765(02)00165-0 PG 7 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700025 ER PT J AU Williams, KE AF Williams, KE TI Overcoming Genesis mission design challenges SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Genesis is the fifth mission selected as part of NASA's Discovery Program. The objective of Genesis is to collect solar wind samples for a period of approximately 2 years while in a halo orbit about the Sun-Earth colinear libration point, L1, located between the Sun and Earth. At the end of this period, the spacecraft follows a free-return trajectory with the samples delivered to a specific recovery point on the Earth for subsequent analysis. This type of sample return has never been attempted before and presents a formidable challenge, particularly with regard to planning and execution of propulsive maneuvers. Moreover, since the original inception, additional challenges have arisen as a result of emerging spacecraft design concerns and operational constraints. This paper will describe how these challenges have been met to date in the context of the better-faster-cheaper paradigm. [This paper addresses an earlier mission design, as of May 2000.] (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Genesis Project, Pasadena, CA 91109 USA. RP Williams, KE (reprint author), CALTECH, Jet Prop Lab, Genesis Project, 4800 Oak Grove Dr,M-S 301-125, Pasadena, CA 91109 USA. NR 5 TC 6 Z9 6 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 281 EP 287 AR PII S0094-5765(02)00167-4 DI 10.1016/S0094-5765(02)00167-4 PG 7 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700027 ER PT J AU Brophy, J AF Brophy, J TI Advanced ion propulsion systems for affordable deep-space missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB A key feature of future deep-space science missions will be the need for significantly greater on-board propulsion capability. To meet this need, ion propulsion based on the technology that flew on NASA's Deep Space I spacecraft has now entered the mainstream of propulsion options available for deep-space missions. The next most likely science mission to use ion propulsion is the comet nucleus sample return (CNSR) mission. CNSR has recently been identified by the Solar System Exploration Subcommittee as the highest priority new mission for NASA's Exploration of the Solar System theme. Ion propulsion for CNSR enables the use of a smaller, less expensive launch vehicle, and significantly shortens the overall trip time. A trade study for CNSR was performed to identify engine and system technology improvements, which provide the greatest mission benefits for the lowest additional risk. This trade study indicated that the maximum specific impulse of the ion engine should be increased from 3100 to 3800 s and that the maximum engine input power should be increased from 2.3 to 3.2 M Simultaneously the engine total propellant throughput capability must be increased from the 80-kg NSTAR design point to approximately 180 kg. A focused technology program to make these advances is underway. (C) 2002 Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Brophy, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 6 TC 28 Z9 28 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 309 EP 316 AR PII S0094-5765(02)00170-4 DI 10.1016/S0094-5765(02)00170-4 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700030 ER PT J AU Leipold, M Eiden, M Gamer, CE Herbeck, L Kassing, D Niederstadt, T Kruger, T Pagel, G Rezazad, M Rozemeijer, H Seboldt, W Schoppinger, C Sickinger, C Unckenbold, W AF Leipold, M Eiden, M Gamer, CE Herbeck, L Kassing, D Niederstadt, T Kruger, T Pagel, G Rezazad, M Rozemeijer, H Seboldt, W Schoppinger, C Sickinger, C Unckenbold, W TI Solar sail technology development and demonstration SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB Solar sail technology holds the promise of significantly enhancing the interplanetary infrastructure for low-cost space exploration missions in the new millennium by exploiting the freely available space resource of solar radiation pressure for primary propulsion. Although the basic idea behind solar sailing appears simple, challenging engineering problems have to be solved. Based on promising results obtained during system studies by DLR (in cooperation with NASA/JPL) and ESA, a joint effort for the development and demonstration of the critical technologies on a co-funding basis was initiated in mid-1998. As a first major milestone in terms of demonstration a 20 in x 20 m breadboard model was developed, manufactured and tested in December 1999. It demonstrates the feasibility of a fully deployable lightweight solar sail structure in simulated 0g environment under ambient environmental conditions. The paper summarizes the main results of the ground tests and recommends next steps in solar sail technology development. (C) 2002 Published by Elsevier Science Ltd. C1 DLR, German Aerosp Ctr, Inst Planetary Explorat Mission, Architecture & Adv Technol Sect, Cologne, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. INVENT GmbH, Braunschweig, Germany. RP Leipold, M (reprint author), DLR, German Aerosp Ctr, Inst Planetary Explorat Mission, Architecture & Adv Technol Sect, Cologne, Germany. NR 3 TC 26 Z9 34 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 317 EP 326 AR PII S0094-5765(02)00171-6 DI 10.1016/S0094-5765(02)00171-6 PG 10 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700031 ER PT J AU Saunders, M Richie, W Rogers, J Moore, A AF Saunders, M Richie, W Rogers, J Moore, A TI Predicting mission success in small satellite missions SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB In our global society with its increasing international competition and tighter financial resources, governments, commercial entities and other organizations are becoming critically aware of the need to ensure that space missions can be achieved on time and within budgets. This has become particularly true for the National Aeronautics and Space Administration's (NASA) Office if Space Science (OSS) which has developed their Discovery and Explorer programs to meet this need. As technologies advance, space missions are becoming smaller and more capable than their predecessors. The ability to predict the mission success of these small satellite missions is critical to the continued achievement of NASA science mission objectives. The NASA OSS, in cooperation with the NASA Langley Research Center, has implemented a process to predict the likely success of missions proposed to its Discovery and Explorer programs. This process is becoming the basis for predicting mission success in many other NASA programs as well. This paper describes the process, methodology, tools and synthesis techniques used to predict mission success of this class of mission. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Space Sci Support Off, Hampton, VA 23665 USA. RP Saunders, M (reprint author), NASA, Langley Res Ctr, Space Sci Support Off, Hampton, VA 23665 USA. NR 1 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 361 EP 370 AR PII S0094-5765(02)00176-5 DI 10.1016/S0094-5765(02)00176-5 PG 10 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700036 ER PT J AU Glenar, DA Blaney, DL Hillman, JJ AF Glenar, DA Blaney, DL Hillman, JJ TI AIMS: Acousto-optic imaging spectrometer for spectral mapping of solid surfaces SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB ID MARS; CLOUDS AB A compact, two-channel acousto-optic tunable filter (AOTF) camera is being built at GSFC as a candidate payload instrument for future Mars landers or small-body rendezvous missions. This effort is supported by the NASA Mars Instrument Development Program (MIDP), Office of Space Science Advanced Technologies and Mission Studies. Acousto-optic Imaging Spectrometer (AIMS) is electronically programmable and provides arbitrary spatial and spectral selection from 0.48 to 2.4 mum. The geometric throughput of AOTF's are well matched to the requirements for lander mounted cameras since (I) they can be made very compact, (II) "slow" (f/14-f/18) optics required for large depth-of-field fall well within the angular aperture limit of AOTF's, and (III) they operate at low ambient temperatures. A breadboard of the AIMS short-wavelength channel is now being used for spectral imaging of high-interest Mars analog materials (iron oxides, carbonates, sulfates and sedimentary basalts) as part of the initial instrument validation exercises. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Glenar, DA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 14 TC 7 Z9 7 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 389 EP 396 AR PII S0094-5765(02)00179-0 DI 10.1016/S0094-5765(02)00179-0 PG 8 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700039 ER PT J AU Deininger, WD Noecker, MC Wiemer, DJ Etenro, JS Cleven, C Patel, KC Blackwood, GH Livesay, LL AF Deininger, WD Noecker, MC Wiemer, DJ Etenro, JS Cleven, C Patel, KC Blackwood, GH Livesay, LL TI Space technology three: mission overview and spacecraft concept description SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB ID INTERFEROMETER AB Space Technology Three (ST3), the third NASA New Millennium Program space technology mission, is focused on validation of key technologies for future separated spacecraft interferometers, such as Terrestrial Planet Finder and the Micro-Arcsecond X-ray Imaging Mission. The main technologies to be demonstrated are autonomous formation flying (AFF) and separated spacecraft interferometry (SSI). This mission uses two spacecraft called the Combiner and Collector, launched together, to validate these technologies. After on-orbit checkout, the spacecraft separate and are maintained within a range of 50-1000 m. The AFF sensors and control capabilities are validated over a 2 month period followed by three months of SSI operations. Launch into an Earth-trailing heliocentric orbit is tentatively planned for March 2005 on a Delta II 7325. JPL is responsible for formation flying sensors and the interferometer instruments. Ball, selected as ST3 prime and working with JPL, provides the two spacecraft, system integration and test, and operations over the six-month mission duration. This paper summarizes the baseline mission concept and describes the spacecraft bus design in more detail, as defined at the start of the program in November 1999. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deininger, WD (reprint author), Ball Aerosp & Technol Corp, POB 1062, Boulder, CO 80306 USA. NR 8 TC 5 Z9 5 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 455 EP 465 AR PII S0094-5765(02)00188-1 DI 10.1016/S0094-5765(02)00188-1 PG 11 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700048 ER PT J AU Deininger, WD Epstein, KW Eterno, JS Andreozzi, L Sieger, S Leschly, K AF Deininger, WD Epstein, KW Eterno, JS Andreozzi, L Sieger, S Leschly, K TI Low cost access to Mars - Mars micromissions spacecraft SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 4th IAA International Conference on Low Cost Planetary Missions CY MAY 02-05, 2000 CL JOHNS HOPKINS UNIV, APPL PHYS LAB, LAUREL, MARYLAND SP IAA HO JOHNS HOPKINS UNIV, APPL PHYS LAB AB The Mars micromission (MM) spacecraft (MMSC) is a multi-purpose platform capable of orbiting Mars for communications/navigation and science payloads or for precision Mars flybys to drop up to six probes. An MMSC is launched as a secondary payload on an Ariane 5 rocket from Kourou, French Guiana, to GTO using the Ariane 5 structure for auxiliary payloads (ASAP5). The maximum launch wet mass is 222 kg and can include up to 45 kg of payload depending on DeltaV needs. The on-board propulsion system is used for maneuvering in the Earth-Moon system and injecting the spacecraft into Mars transfer orbit and, if needed, Mars orbit. The first MMSC to be launched in early 2003 will be a Communications/Navigation (Comm/Nav) Orbiter. JPL is responsible for the Comm/Nav payload. Ball Aerospace, working with JPL, provides the multi-purpose spacecraft bus, system integration and test, and assists in operations over the 3 year mission duration. This paper summarizes the baseline spacecraft concept for the first Mars Com/Nav mission as defined at the start of the program in February 2000 and describes the spacecraft bus implementation in more detail. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. Aerojet, Sacramento, CA 95813 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Deininger, WD (reprint author), Ball Aerosp & Technol Corp, POB 1062, Boulder, CO 80306 USA. NR 5 TC 2 Z9 2 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD JAN-MAR PY 2003 VL 52 IS 2-6 BP 501 EP 510 AR PII S0094-5765(02)00193-5 DI 10.1016/S0094-5765(02)00193-5 PG 10 WC Engineering, Aerospace SC Engineering GA 643RF UT WOS:000180873700053 ER PT S AU Yang, EH Shcheglov, K AF Yang, EH Shcheglov, K BE Wizinowich, PL Bonaccini, D TI A piezoelectric unimorph deformable mirror concept by wafer transfer for ultra large space telescopes SO ADAPTIVE OPTICAL SYSTEM TECHNOLOGIES II, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical System Technologies II CY AUG 22-26, 2002 CL WAIKOLOA, HI SP SPIE DE deformable mirror (DM); MicroElectroMechanical Systems (MEMS); adaptive optics; piezoelectric actuator; unimorph membrane; continuous mirror; wafer-level membrane transfer; segmented space telescope AB Future concepts of ultra large space telescopes include the telescopes with segmented silicon mirrors and inflatable polymer mirrors. Primary mirrors for these systems cannot meet optical surface figure requirements and are likely to generate over several microns of wavefront errors. In order to correct for these large wavefront errors, high stroke optical quality deformable mirrors are required. The deformable mirror in this paper consists of an optical quality membrane mirror backed by a piezoelectric unimorph actuator array. A fabrication technology has been recently developed for transferring an entire wafer-level mirror membrane from one substrate to another. A thin membrane, 100 mm in diameter, has been successfully transferred without using adhesives or polymers. The measured peak-to-valley surface figure error of a wafer-level transferred and patterned membrane (1 mm x 1 mm x 0.016 mm) is only 9 mm. The mirror element actuation principle is based on a piezoelectric unimorph. A voltage applied to the piezoelectric layer induces stress in the longitudinal direction causing the film to deform and pull on the mirror connected to it. The advantage of this approach is that the small longitudinal strains obtainable from a piezoelectric material at modest voltages are thus translated into large vertical displacements. Modeling is performed for unimorph membranes consisting of clamped rectangular membranes with piezoelectric layers with variable dimensions. The membrane transfer technology combined with the piezoelectric unimorph actuator concept constitutes the successful demonstration of high quality, compact, large stroke continuous deformable mirror devices, resulting in compact AO systems for use in ultra large space telescopes. C1 CALTECH, Jet Prop Lab, In Situ Technol & Expt Syst Sect, MEMS Technol Grp, Pasadena, CA 91109 USA. RP Yang, EH (reprint author), CALTECH, Jet Prop Lab, In Situ Technol & Expt Syst Sect, MEMS Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Yang, Eui-Hyeok/0000-0003-4893-1691 NR 11 TC 5 Z9 5 U1 0 U2 3 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4618-1 J9 P SOC PHOTO-OPT INS PY 2003 VL 4839 BP 703 EP 710 DI 10.1117/12.456992 PN 1&2 PG 8 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BW43V UT WOS:000181980700073 ER PT S AU Truong, T Brack, G Troy, M Trinh, T Shi, F Dekany, R AF Truong, T Brack, G Troy, M Trinh, T Shi, F Dekany, R BE Wizinowich, PL Bonaccini, D TI Real-time wavefront processors for the next generation of adaptive optics systems: A design and analysis SO ADAPTIVE OPTICAL SYSTEM TECHNOLOGIES II, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical System Technologies II CY AUG 22-26, 2002 CL WAIKOLOA, HI SP SPIE DE adaptive optics; wavefront processors; TMS320C6701 AB Adaptive optics (AO) systems currently under investigation will require at least two orders of magitude increase in the number of actuators, which in turn translates to effectively a 104 increase in compute latency. Since the performance of an AO system invariably improves as the compute latency decreases, it is important to study how today's computer systems will scale to address this expected increase in actuator utilization. This paper answers this question by characterizing the performance of a single deformable mirror (DM) Shack-Hartmann natural guide star AO system implemented on the present-generation digital signal processor (DSP) TMS320C6701 from Texas Instruments. We derive the compute latency of such a system in terms of a few basic parameters, such as the number of DM actuators, the number of data channels used to read out the camera pixels, the number of DSPs, the available memory bandwidth, as well as the inter-processor communication (IPC) bandwidth and the pixel transfer rate. We show how the results would scale for future systems that utilizes multiple DMs and guide stars. We demonstrate that the principal performance bottleneck of such a system is the available memory bandwidth of the processors and to lesser extent the IPC bandwidth. This paper concludes with suggestions for mitigating this bottleneck. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Truong, T (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 5 Z9 5 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4618-1 J9 P SOC PHOTO-OPT INS PY 2003 VL 4839 BP 911 EP 922 DI 10.1117/12.459353 PN 1&2 PG 12 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BW43V UT WOS:000181980700094 ER PT S AU Shi, F MacMartin, DG Troy, M Brack, GL Burruss, RS Dekany, RG AF Shi, F MacMartin, DG Troy, M Brack, GL Burruss, RS Dekany, RG BE Wizinowich, PL Bonaccini, D TI Sparse matrix wavefront reconstruction: Simulations and experiments SO ADAPTIVE OPTICAL SYSTEM TECHNOLOGIES II, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Adaptive Optical System Technologies II CY AUG 22-26, 2002 CL WAIKOLOA, HI SP SPIE DE adaptive optics; wavefront sensor; wavefront reconstruction; decentralized control AB Adaptive optics systems with Shack-Hartmann wavefront sensors require reconstruction of the atmospheric phase error from subaperture slope measurements, with every sensor in the array being used in the computation of each actuator command. This fully populated reconstruction matrix can result in a significant computational burden for adaptive optics systems with large numbers of actuators. A method for generating sparse wavefront reconstruction matrices for adaptive optics is proposed. The method exploits the relevance of nearby subaperture slope measurements for control of an individual actuator, and relies upon the limited extent of the influence function for a zonal deformable mirror. Relying only on nearby sensor information can significantly reduce the calculation time for wavefront reconstruction. In addition, a hierarchic controller is proposed to recover some of the global wavefront information. The performance of these sparse wavefront reconstruction matrices was evaluated in simulation, and tested on the Palomar Adaptive Optics System. This paper presents some initial results from the simulations and experiments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Shi, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI MacMartin, Douglas/A-6333-2016 OI MacMartin, Douglas/0000-0003-1987-9417 NR 9 TC 10 Z9 10 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4618-1 J9 P SOC PHOTO-OPT INS PY 2003 VL 4839 BP 1035 EP 1044 DI 10.1117/12.457134 PN 1&2 PG 10 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BW43V UT WOS:000181980700106 ER PT J AU Ding, J AF Ding, J TI Materials and processes for NASA's shuttle program SO ADVANCED MATERIALS & PROCESSES LA English DT Article AB This article, the first in our series celebrating the Centennial of Flight, describes some of the Space Shuttle materials and, fabrication processes. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Ding, J (reprint author), NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 1 Z9 3 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD JAN PY 2003 VL 161 IS 1 BP 69 EP 71 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 635QE UT WOS:000180409700015 ER PT J AU Ettinger, SM Nechyba, MC Ifju, PG Waszak, M AF Ettinger, SM Nechyba, MC Ifju, PG Waszak, M TI Vision-guided flight stability and control for micro air vehicles SO ADVANCED ROBOTICS LA English DT Article; Proceedings Paper CT IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2002) CY SEP 30-OCT 04, 2002 CL LAUSANNE, SWITZERLAND SP IEEE Robot & Automat Soc, IEEE Ind Electr Soc, Robot Soc Japan, Soc Instruments & Control Engineers, INRIA Rhone Alpes Grenoble, EPFL Lausanne DE vision-based control; aerial robotics; real-time control AB Substantial progress has been made recently towards designing, building and test-flying remotely piloted micro air vehicles (MAVs) and small unmanned air vehicles. We seek to complement this progress in overcoming the aerodynamic obstacles to flight at very small scales with a vision-guided flight stability and autonomy system, based on a robust horizon detection algorithm. In this paper, we first motivate the use of computer vision for MAV autonomy, arguing that given current sensor technology, vision may be the only practical approach to the problem. We then describe our statistical vision-based horizon detection algorithm, which has been demonstrated at 30 Hz with over 99.9% correct horizon identification. Next, we develop robust schemes for the detection of extreme MAV attitudes, where no horizon is visible, and for the detection of horizon estimation errors, due to external factors such as video transmission noise. Finally, we discuss our feedback controller for self-stabilized flight and report results on vision-based autonomous flights of duration exceeding 10 min. We conclude with an overview of our on-going and future MAV-related research. C1 Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. NASA, Dynam & Control Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP Nechyba, MC (reprint author), Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA. NR 17 TC 56 Z9 61 U1 0 U2 15 PU VSP BV PI ZEIST PA PO BOX 346, 3700 AH ZEIST, NETHERLANDS SN 0169-1864 J9 ADV ROBOTICS JI Adv. Robot. PY 2003 VL 17 IS 7 BP 617 EP 640 DI 10.1163/156855303769156983 PG 24 WC Robotics SC Robotics GA 728EM UT WOS:000185703400004 ER PT S AU Pang, WL Goodwin, SD AF Pang, WL Goodwin, SD BE Xiang, Y ChaibDraa, B TI A graph based backtracking algorithm for solving general CSPs SO ADVANCES IN ARTIFICIAL INTELLIGENCE, PROCEEDINGS SE LECTURE NOTES IN ARTIFICIAL INTELLIGENCE LA English DT Article; Proceedings Paper CT 16th Conference of the Canadian-Society-for-Computational-Studies-of-Intelligence CY JUN 11-13, 2003 CL HALIFAX, CANADA SP Canadian Soc Computat Studies Intelligence, Natl Res Council Canada ID TRACTABLE CONSTRAINTS; GLOBAL CONSISTENCY; DECOMPOSITION; NETWORKS AB Many AI tasks can be formalized as constraint satisfaction problems (CSPs), which involve finding values for variables subject to constraints. While solving a CSP is an NP-complete task in general, tractable classes of CSPs have been identified based on the structure of the underlying constraint graphs. Much effort has been spent on exploiting structural properties of the constraint graph to improve the efficiency of finding a solution. These efforts contributed to development of a class of CSP solving algorithms called decomposition algorithms. The strength of CSP decomposition is that its worst-case complexity depends on the structural properties of the constraint graph and is usually better than the worst-case complexity of search methods. Its practical application is limited, however, since it cannot be applied if the CSP is not decomposable. In this paper, we propose a graph based backtracking algorithm called omega-CDBT, which shares merits and overcomes the weaknesses of both decomposition and search approaches. C1 NASA, Ames Res Ctr, QSS Grp Inc, Moffett Field, CA 94035 USA. Univ Windsor, Sch Comp Sci, Windsor, ON N9B 3P4, Canada. RP Pang, WL (reprint author), NASA, Ames Res Ctr, QSS Grp Inc, Moffett Field, CA 94035 USA. NR 29 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-40300-0 J9 LECT NOTES ARTIF INT PY 2003 VL 2671 BP 114 EP 128 PG 15 WC Computer Science, Artificial Intelligence SC Computer Science GA BX29V UT WOS:000184853500009 ER PT S AU Zhu, DM Bansal, NP Miller, RA AF Zhu, DM Bansal, NP Miller, RA BE Bansal, NP Singh, JP Kriven, WM Schneider, H TI Thermal conductivity and stability of HfO2-Y2O3 and La2Zr2O7 evaluated for 1650 degrees C thermal/environmental barrier coating applications SO ADVANCES IN CERAMIC MATRIX COMPOSITES IX SE CERAMIC TRANSACTIONS LA English DT Proceedings Paper CT International Symposium on Recent Advances in Ceramic Matrix Composites CY APR 27-30, 2003 CL Nashville, TN SP NASA Glenn Res Ctr, Engn Ceram Div, Amer Ceram Soc AB HfO2-Y2O3 and La2Zr2O7 are candidate thermal and environmental barrier coating (T/EBC) materials for gas turbine ceramic matrix composite (CMC) combustor applications because of their relatively low thermal conductivity and high temperature capability. In this paper, thermal conductivity and high temperature stability of hot-pressed and plasma-sprayed specimens with representative partially-stabilized and fully-cubic HfO2-Y2O3 compositions and La2Zr2O7 were evaluated at temperatures up to 1700degreesC using a steady-state laser heat-flux technique. Sintering behavior of the plasma-sprayed coatings was determined by monitoring the thermal conductivity increases during a 20-hour test period at various temperatures. Durability and failure mechanisms of the HfO2-Y2O3 and La2Zr2O7 coatings on mullite/SiC hexoloy or SiC/SiC CMC substrates were investigated at 1650degreesC under thermal gradient cyclic conditions. Coating design and testing issues for the 1650degreesC thermal/environmental barrier coating applications are also discussed. C1 USA, Res Lab, Vehicle Technol Directorate, NASA,John H Glenn Res Ctr, Cleveland, OH 44135 USA. RP Zhu, DM (reprint author), USA, Res Lab, Vehicle Technol Directorate, NASA,John H Glenn Res Ctr, Cleveland, OH 44135 USA. NR 7 TC 7 Z9 8 U1 0 U2 6 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, WESTERVILLE, OH 43081-8720 USA SN 1042-1122 BN 1-57498-207-9 J9 CERAM TRANS PY 2003 VL 153 BP 331 EP 343 PG 13 WC Materials Science, Ceramics; Materials Science, Composites SC Materials Science GA BY77C UT WOS:000189459100023 ER PT B AU Sandor, M Agarwal, S Peters, D Cooper, MS AF Sandor, M Agarwal, S Peters, D Cooper, MS GP ASME TI Reliability of low glass transition temperature COTS PEM'S for space applications SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 1 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div AB Microcircuit manufacturers of Plastic Encapsulated Microcircuits (PEM's) have made changes in epoxy molding compound materials and chemistry, which lower Glass Transition Temperature (Tg). PEM users in harsh environments have concerns if either the part in its application, or in evaluation or assembly, is used close to, or above, the Tg. Various Tg measurement techniques are available and discussed. Test results from one technique is reviewed. The implications of the Tg results on usage of these parts in space applications will be presented. Burn-in/ reliability test results of samples with low Tg PEM's will be presented. The reliability experiments include testing under different temperatures. The issue being addressed is whether outgassing of molding compounds occurs when the temperature of the molding compound exceeds the Tg. This is a caution noted by many vendors. As an example outgassing of flame retardants can degrade parametric performance and wire bond integrity. This would be the case when PEMS are being qualified for Space applications using burn-in or in storage environments. JPL's past experience has shown that COTS PEMS parametrics can degrade significantly even when the burn-in temperature is well below the Tg. Two different microcircuits exhibiting low Tg were evaluated. Assessment of final electrical test measurements and yield are shown. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sandor, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3690-8 PY 2003 BP 809 EP 815 PG 7 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BAK06 UT WOS:000222624900108 ER PT B AU Wright, MW Franzen, D Hemmati, H Sandor, M AF Wright, MW Franzen, D Hemmati, H Sandor, M GP ASME TI Qualification and reliability testing of a microchip laser system for space applications SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 1 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div AB A compact microchip laser pumped by a single fiber coupled diode laser was developed for a scanning laser radar instrument called Laser Mapper (LAMP) to be used as a guidance and control sensor in future JPL/NASA missions [1]. The system involves commercial-off-the-shelf components that were packaged and qualified for space applications. In particular, the system has to meet a 5000 hour minimum life requirement on a LEO platform. This paper discusses the process being used and the results of the selection and qualification of a low cost prepackaged diode laser with a custom packaged microchip laser crystal. The environmental testing would be applicable to a variety of commercial photonic systems. The topics to be discussed include: The selection of the diode pump laser Upscreening of commercial parts Qualification sampling tests including temperature cycling, vibration, outgassing Physical construction analysis The testing requirements and screening flow to ensure the lifetime reliability will be presented. This was determined based on input from Telcordia standards that apply to optoelectronic systems used in the telecommunications industry but upgraded to account for the unique aspects of the devices, such as the high optical power. The key elements in packaging high power optoelectronic devices for harsh environments include managing the thermal loading through the expected spacecraft temperature extremes and addressing the die mounting, optical fiber coupling and jacket assembly. Each of these aspects will be discussed in light of the testing results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wright, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 1 U2 2 PU AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3690-8 PY 2003 BP 879 EP 883 PG 5 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Characterization & Testing; Optics SC Engineering; Materials Science; Optics GA BAK06 UT WOS:000222624900116 ER PT B AU Chao, TH Reyes, G Zhou, H AF Chao, TH Reyes, G Zhou, H GP asme TI Rugged portable grayscale optical correlator for onboard automatic target recognition applications SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 2 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div ID CORRELATION FILTERS AB Jet Propulsion Laboratory (JPL) has developed, for the first time, a matchbox-size compact grayscale optical correlator (GOC) In this paper, we will report the recent development of a prototype 512 x 512 GOC utilizing a new miniature ferroelectric liquid crystal spatial light modulator (FLCSLM) with a 7-micron pixel pitch. We will discuss recent progress in the design and packaging technology to achieve a rugged portable GOC module to enable the real-time onboard applications of this miniature GOC. Experimental demonstration of ATR applications using this new GOC will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chao, TH (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 AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3691-6 PY 2003 BP 779 EP 782 PG 4 WC Engineering, Aerospace; Thermodynamics; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Thermodynamics; Telecommunications GA BAK08 UT WOS:000222625600105 ER PT B AU Hunter, DJ AF Hunter, DJ GP asme TI Integrated avionics system (IAS), integrating 3-D technology on a spacecraft panel SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 2 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div AB As spacecraft designs converge toward miniaturization, and with the volumetric and mass challenges placed on avionics, programs will continue to advance the "state of the art" in spacecraft system development with new challenges to reduce power, mass and volume. Traditionally, the trend is to focus on high-density component packaging technologies. Industry has made significant progress in these technologies, and other related internal and external interconnection schemes. Although new technologies have improved packaging densities, a system packaging architecture is required that not only reduces spacecraft volume and mass budgets, but increase integration efficiencies, provide modularity and flexibility to accommodate multiple missions while maintaining a low recurring cost. With these challenges in mind, a novel system packaging approach incorporates solutions that provide broader environmental applications, more flexible system interconnectivity, scalability, and simplified assembly test and integration schemes. The Integrated Avionics System (IAS) provides for a low-mass, modular distributed or centralized packaging architecture which combines ridged-flex technologies, high-density COTS hardware and a new 3-D mechanical packaging approach, Horizontal Mounted Cube (HMC). This paper will describe the fundamental elements of the IAS, HMC hardware design, system integration and environmental test results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hunter, DJ (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 AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3691-6 PY 2003 BP 789 EP 795 PG 7 WC Engineering, Aerospace; Thermodynamics; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Thermodynamics; Telecommunications GA BAK08 UT WOS:000222625600107 ER PT B AU Schatzel, D AF Schatzel, D GP asme TI Develpoment of reliable electronic packaging solutions for spacecraft avionics miniaturization using embedded passive devices SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 2 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div AB Miniaturization of electronic packages will play a key role in future space avionics systems. Smaller avionics packages will reduce payloads while providing greater functionality for information processing and mission instrumentation. Current surface mount technology discrete passive devices not only take up significant space but also add weight. To that end, the use of embedded passive devices, such as capacitors, inductors and resistors will be instrumental in allowing electronics to be made smaller and lighter. Embedded passive devices fabricated on silicon or like substrates using thin film technology, promise great savings in circuit volume, as well as potentially improving electrical performance by decreasing parasitic losses. These devices exhibit a low physical profile and allow the circuit footprint to be reduced by stacking passive elements within a substrate. Thin film technologies used to deposit embedded passive devices are improving and costs associated with the process are decreasing. There are still many challenges with regard to this approach that must be overcome. In order to become a viable approach these devices need to work in conjunction with other active devices such as bumped die (flip chip) that share the same substrate - area. This dictates that the embedded passive devices are resistant to the subsequent assembly processes associated with die attach (temperature, pressure). Bare die will need to be mounted directly on top of one or more layers of embedded passive devices. Currently there is not an abundant amount of information available on the reliability of these devices when subjected to the high temperatures of die attach or environmental thermal cycling for space environments. Device performance must be consistent overtime and temperature with minimal parasitic loss. Pretested and assembled silicon substrates with layers of embedded capacitors made with two different dielectric materials, Ta2O5 (Tantalum Oxide) and benzocyclobutene (BCB), were subjected to the die attach process and tested for performance in an ambient environment. These assemblies were subjected to environmental thermal cycling from -55degreesC to 100degreesC. Preliminary results indicate embedded passive capacitors and resistors can fulfill the performance and reliability requirements of space flight on future missions. Testing results are encouraging for continued development of integrating embedded passive devices to replace conventional electronic packaging methods. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schatzel, D (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 AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3691-6 PY 2003 BP 797 EP 800 PG 4 WC Engineering, Aerospace; Thermodynamics; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Thermodynamics; Telecommunications GA BAK08 UT WOS:000222625600108 ER PT B AU Gerke, RD Shapiro, AA Peters, DM AF Gerke, RD Shapiro, AA Peters, DM GP asme TI Use of plastic commercial off-the-shelf (COTS) microcircuits for space applications SO ADVANCES IN ELECTRONIC PACKAGING 2003, VOL 2 LA English DT Proceedings Paper CT International Electronic Packaging Technical Conference CY JUL 06-11, 2003 CL Maui, HI SP Amer Soc Mech Engineers, Elect & Photon Packaging Div AB Commercial-off-the-shelf (COTS) plastic encapsulated microcircuits (PEM) are candidate-packaging technologies for spacecraft due to their enhanced performance, lower weight and lower cost. Much of the electronics used in space applications would be considered obsolete by everyday standards. This is primarily due the cost and time required for full space qualification. In order to gain the performance available in today's electronics, COTS PEMs offer a viable path. PEMs can weigh half as much as their counter part ceramic packages. A lighter package results in a smaller overall payload for the same board functionality, a concern of critical importance for space missions because the payload mass dictates the launch vehicle requirements. Costs can be potentially reduced by using screening, accelerated testing or partial qualification techniques to complement the existing commercial qualification as well as by the reduced package materials costs. Assessing the risk associated with potentially lower reliability devices, engineers within the commercial and aerospace industries are using tradeoff and risk analysis to aid in reducing spacecraft system cost while increasing performance and maintaining high reliability. In this paper we will outline the issues facing the-use of COTS PEMs for spaceflight hardware from the aspect of both the electronic active devices as well as their packages. Finally, we will provide some guidelines for their use. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Gerke, RD (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 13 TC 0 Z9 0 U1 1 U2 2 PU AMER SOC MECHANICAL ENGINEERS PI NEW YORK PA THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA BN 0-7918-3691-6 PY 2003 BP 801 EP 808 PG 8 WC Engineering, Aerospace; Thermodynamics; Engineering, Electrical & Electronic; Telecommunications SC Engineering; Thermodynamics; Telecommunications GA BAK08 UT WOS:000222625600109 ER PT B AU Ogbuji, LUJT Humphrey, DL Setlock, JA AF Ogbuji, LUJT Humphrey, DL Setlock, JA BE Pandey, AB Kendig, KL Lewandowski, JJ Shah, SS TI "A simplified test for blanching susceptibility of Cu alloys" SO AFFORDABLE METAL MATRIX COMPOSITES FOR HIGH-PERFORMANCE APPLICATIONS II LA English DT Proceedings Paper CT International Symposium on Powder Materials - Current Research and Industrial Practices III held at the Materials Science and Technology Meeting CY NOV 09-12, 2003 CL CHICAGO, IL SP TMS Powder Mat Comm DE Cu-matrix composites; oxidation; blanching; oxidation-reduction testing AB Advanced copper alloys, some of which are essentially metal-matrix composites, are being developed for hot-section liner service in high-heat-flux engines. In that application they are prone to degradation from repeated cycles of oxidation-reduction, a phenomenon called blanching. To date no simple test exists to assess the blanching resistance of a material. A simple test was devised for that purpose, based on in-situ thermogravimetric analysis with the furnace cycled between oxidizing and reducing conditions. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Ogbuji, LUJT (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-557-3 PY 2003 BP 25 EP 33 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BY52G UT WOS:000189399400003 ER PT J AU Maestrello, L AF Maestrello, L TI Laminarization of turbulent boundary layer on flexible and rigid surfaces SO AIAA JOURNAL LA English DT Article ID INSTABILITY WAVES; CHAOS; PANEL; FLOWS AB An investigation of the control of turbulent boundary-layer flow over flexible and rigid surfaces downstream of a concave-convex geometry has been made. The concave-convex curvature induces centrifugal forces and a pressure gradient that affect the growth of the turbulent boundary layer. The favorable gradient is not sufficient to overcome the unfavorable one; thus, the net effect is a destabilization of the flow into Gortler instabilities. This study shows that control of the turbulent boundary layer and structural loading can be successfully achieved by using localized surface heating because the subsequent cooling and geometrical shaping downstream over a favorable pressure gradient are effective in laminarization of the turbulence. Wires embedded in a thermally insulated substrate provide surface heating. The laminarized velocity profile lowers the Reynolds number, and it reduces the structure loading. In the laminarization, the turbulent energy is dissipated by the molecular transport due to both viscous and conductivity mechanisms. Laminarization also reduces spanwise vorticity because of the longitudinal temperature gradient of the sublayer profile. The results demonstrate that the curvature-induced mean pressure gradient enhances the receptivity of the flow to a localized surface heating, a potentially viable mechanism to laminarize turbulent boundary-layer flow; thus, the laminarized flow reduces the response of the flexible structure and the resultant sound radiation. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Maestrello, L (reprint author), NASA, Langley Res Ctr, Mail Stop 463, Hampton, VA 23681 USA. NR 24 TC 1 Z9 1 U1 0 U2 1 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 JAN PY 2003 VL 41 IS 1 BP 34 EP 39 DI 10.2514/2.1932 PG 6 WC Engineering, Aerospace SC Engineering GA 671RN UT WOS:000182478000004 ER PT J AU Ding, HL Yang, BG Lou, M Fang, HF AF Ding, HL Yang, BG Lou, M Fang, HF TI New numerical method for two-dimensional partially wrinkled membranes SO AIAA JOURNAL LA English DT Article ID NONLINEAR COMPLEMENTARITY-PROBLEMS; TENSION STRUCTURES AB Based on the introduction of a nonnegative adjustable parameter into Poisson's ratio, a new numerical method is proposed to solve numerically the partially wrinkled membrane problems with arbitrary complex shapes. Three fundamental issues in this new method are addressed. First, a nonnegative adjustable parameter is introduced into the constitutive law, automatically representing unwrinkled (taut) and wrinkled states of a membrane. Second, a parametric variational principle is developed for the new membrane model. Third, by the variational principle, the original membrane problem is converted to a nonlinear mathematical programming problem. The variational principle and the mathematical programming formulation lay a foundation for efficient numerical analysis of wrinkled membrane structures using finite element discretization. Three typical examples are given to show the effectiveness of this method. C1 Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Sci & Technol Dev Sect, Pasadena, CA 91109 USA. RP Ding, HL (reprint author), Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA. NR 28 TC 13 Z9 15 U1 0 U2 1 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 JAN PY 2003 VL 41 IS 1 BP 125 EP 132 DI 10.2514/2.1922 PG 8 WC Engineering, Aerospace SC Engineering GA 671RN UT WOS:000182478000015 ER PT S AU Kiang, RK Hulina, SM Masuoka, PM Claborn, DM AF Kiang, RK Hulina, SM Masuoka, PM Claborn, DM BE Shen, SS Lewis, PE TI Identification of mosquito larval habitats in high resolution satellite data SO ALGORITHMS AND TECHNOLOGIES FOR MULTISPECTRAL, HYPERSPECTRAL AND ULTRASPECTRAL IMAGERY IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery IX CY APR 21-24, 2003 CL ORLANDO, FL SP SPIE DE ikonos; pan-sharpening; texture; contextual; malaria; mosquito; habitat AB Mosquito-born infectious diseases are a serious public health concern, not only for the less developed countries, but also for developed countries like the U.S. Larviciding is an effective method for vector control and adverse effects to nontarget species are minimized when mosquito larval habitats are properly surveyed and treated. Remote sensing has proven to be a useful technique for large-area ground cover mapping, and hence, is an ideal tool for identifying potential larval habitats. Locating small larval habitats, however, requires data with very high spatial resolution. Textural and contextual characteristics become increasingly evident at higher spatial resolution. Per-pixel classification often leads to suboptimal results. In this study, we use pan-sharpened Ikonos data, with a spatial resolution approaching I meter, to classify potential mosquito larval habitats for a test site in South Korea. The test site is in a predominantly agricultural region. When spatial characteristics were used in conjunction with spectral data, reasonably good classification accuracy was obtained for the test site. In particular, irrigation and drainage ditches are important larval habitats but their footprints are too small to be detected with the original spectral data at 4-meter resolution. We show that the ditches are detectable using automated classification on pan-sharpened data. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kiang, RK (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 8 TC 1 Z9 1 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4953-9 J9 P SOC PHOTO-OPT INS PY 2003 VL 5093 BP 353 EP 361 DI 10.1117/12.487016 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA BX79U UT WOS:000186472900034 ER PT B AU Lee, JA AF Lee, JA BE Das, SK TI Cast aluminum alloy for high temperature applications SO ALUMINUM 2003 LA English DT Proceedings Paper CT Symposium on Aluminum held at the TMS 2003 Annual Meeting CY MAR 02-06, 2003 CL SAN DIEGO, CA SP Minerals, Met & Mat Soc ID HYDROCARBON EMISSION; CREVICE AB Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 4507 (232degreesC) to about 750degreesF (400degreesC). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Lee, JA (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Stop ED33, Huntsville, AL 35812 USA. NR 11 TC 2 Z9 2 U1 0 U2 3 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-542-5 PY 2003 BP 145 EP 151 PG 7 WC Engineering, Mechanical; Metallurgy & Metallurgical Engineering; Transportation Science & Technology SC Engineering; Metallurgy & Metallurgical Engineering; Transportation GA BX66P UT WOS:000186057900014 ER PT J AU Turner, MS AF Turner, MS TI The New Cosmology: Mid-term report card for inflation SO ANNALES HENRI POINCARE LA English DT Article ID DARK-MATTER; TENSOR PERTURBATIONS; FLATNESS PROBLEMS; UNIVERSE; FLUCTUATIONS; ANISOTROPY; HORIZON; MODELS; SCALAR AB Inflation has been the driving idea in cosmology for two decades and is a pillar of the New Cosmology. The inflationary paradigm has now passed its first round of significant tests, with two of its three basics predictions confirmed at about the 10% level (spatially flat Universe and density perturbations produced from quantum fluctuations with \n - 1\ similar to O(0.1)). The Inflationary Paradigm has some of the truth. Over the next decade the precision of these tests, most of which involve measurements of CMB anisotropy and polarization, will improve 30 fold or more(!), testing inflation more sharply and possibly elucidating the underlying cause. Especially important in this regard is detecting the inflation- produced gravitational waves, either directly or through their CMB polarization signature. While inflation has by no means been verified, its successes have raised the bar for competitor theories: Any alternative must feature the two hallmarks of inflation: superluminal expansion and entropy production. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Ctr Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Turner, MS (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 42 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER BASEL AG PI BASEL PA PICASSOPLATZ 4, BASEL, 4052, SWITZERLAND SN 1424-0637 EI 1424-0661 J9 ANN HENRI POINCARE JI Ann. Henri Poincare PY 2003 VL 4 SU 1 BP S333 EP S346 DI 10.1007/s00023-003-0926-x PG 14 WC Physics, Multidisciplinary; Physics, Particles & Fields; Physics, Mathematical SC Physics GA 760AJ UT WOS:000187787800026 ER PT J AU Amr, S Bollinger, ME Myers, M Hamilton, RG Weiss, SR Rossman, M Osborne, L Timmins, S Kimes, DS Levine, ER Blaisdell, CJ AF Amr, S Bollinger, ME Myers, M Hamilton, RG Weiss, SR Rossman, M Osborne, L Timmins, S Kimes, DS Levine, ER Blaisdell, CJ TI Environmental allergens and asthma in urban elementary schools SO ANNALS OF ALLERGY ASTHMA & IMMUNOLOGY LA English DT Article ID HOUSE-DUST MITE; CHILDHOOD ASTHMA; CAT ALLERGEN; COCKROACH ALLERGENS; INDOOR ALLERGENS; DOMESTIC ALLERGENS; PUBLIC PLACES; RISK-FACTORS; DOG CAN-F-1; CHILDREN AB Background: Asthma in school children is rising, and indoor allergens are very common triggers of asthma attacks; however, the risk of the school environment on asthma has not been well studied. Objective: To determine the presence and the levels of common aeroallergens in schools, where asthma prevalence rates are high. Methods: Settled dust samples were collected from 12 Baltimore City public elementary schools, and they were analyzed for the following allergens: cockroaches (Bla g 1/2), dust mites (Der f 1/p 1), dog (Can f 1), cat (Fel d 1), and mouse (Mus m 1). School asthma prevalence rates were correlated with allergen levels, and association between allergen levels and other risk factors present in the schools' environment was examined. Results: The mean and range levels were 1.49 U/g (0 to 8) for Bla g 1/2; 0.38 mug/g (0 to 11.9) for the Der f 1/p 1; 1.44 mug/g (0.1 to 9.6) for Can f 1; 1.66 mug/g (0.2 to 12) for Fel d 1; and 6.24 mug/g (0.3 to 118.3) for Mus m 1. Dust mite, cat and dog allergens were significantly in rooms with carpet and/or area rugs, compared to rooms with bare floors (P < 0.05). Asthma prevalence rates varied from 11.9 to 20.8% between schools and positively correlation with the mean levels of Bla g 1/2 in the schools (P = 0.001) Conclusions: Common allergens that are known to trigger asthma were detected in all school environments, where asthma prevalence rates were high. However, the overall allergen levels were low, indicating that other factors, including exposures in the homes of asthmatic patients, may have more relevance to sensitization and symptoms than school exposures. C1 Univ Maryland, Sch Med, Dept Epidemiol & Prevent Med, Baltimore, MD 21201 USA. Univ Maryland, Sch Med, Dept Pediat, Div Pulmonol Allergy, Baltimore, MD 21201 USA. Decis Syst Technol, Greenbelt, MD USA. Johns Hopkins Med Inst, Baltimore, MD 21205 USA. Univ Maryland, Sch Med, Ctr Drugs & Publ Policy, Baltimore, MD 21201 USA. Baltimore City Dept Hlth, Sch Hlth Program, Baltimore, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Amr, S (reprint author), Univ Maryland, Sch Med, Dept Epidemiol & Prevent Med, 660 W Redmond St,HH109, Baltimore, MD 21201 USA. NR 47 TC 60 Z9 60 U1 1 U2 4 PU AMER COLL ALLERGY ASTHMA IMMUNOLOGY PI ARLINGTON HTS PA 85 WEST ALGONQUIN RD SUITE 550, ARLINGTON HTS, IL 60005 USA SN 1081-1206 J9 ANN ALLERG ASTHMA IM JI Ann. Allergy Asthma Immunol. PD JAN PY 2003 VL 90 IS 1 BP 34 EP 40 PG 7 WC Allergy; Immunology SC Allergy; Immunology GA 635ZQ UT WOS:000180430400010 PM 12546335 ER PT S AU Hulbe, CL Wang, WL Joughin, IR Siegert, MJ AF Hulbe, CL Wang, WL Joughin, IR Siegert, MJ BE Raymond, CF TI The role of lateral and vertical shear in tributary flow toward a West Antarctic ice stream SO ANNALS OF GLACIOLOGY, VOL 36 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Fast Glacier Flow CY JUN 10-14, 2002 CL YAKUTAT, ALASKA SP Univ Alaska, US Natl Sci Fdn, US Natl Acronaut & Space Adm, Univ Alaska Fairbanks, Geophys Inst, Univ Alaska Fairbanks, Int Arctic Res Ctr, Arctic Res Consortium United States ID EAST ANTARCTICA; LAW DOME; TEMPERATURE; BALANCE; LAYERS; SHEET AB Narrow lateral shear margins are the most distinctive visual feature of the West Antarctic ice streams. Large shear stresses within these layers support the majority of the gravitational driving stress within a fast-flowing ice stream. The present contribution looks upstream, to the tributaries that feed ice-stream onsets, and considers the effects of both horizontal and vertical shear on their flow. Numerical and direct simulations of vertical and horizontal shear are used. Vertical shear, simulated using an anisotropic flow law, is of particular interest. We conclude that by isolating overlying ice from large-amplitude variations in bed elevation, "vertical shear margins" play an important role in sustaining relatively rapid tributary flow. C1 Portland State Univ, Dept Geol, Portland, OR 97207 USA. NASA, Goddard Space Flight Ctr, Raytheon Co, ITSS, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Bristol, Sch Geog Sci, Bristol Glaciol Ctr, Bristol BS8 1SS, Avon, England. RP Hulbe, CL (reprint author), Portland State Univ, Dept Geol, Box 751, Portland, OR 97207 USA. EM chulbe@pdx.edu RI Siegert, Martin/A-3826-2008; Joughin, Ian/A-2998-2008 OI Siegert, Martin/0000-0002-0090-4806; Joughin, Ian/0000-0001-6229-679X NR 31 TC 7 Z9 7 U1 0 U2 3 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-31-8 J9 ANN GLACIOL PY 2003 VL 36 BP 244 EP 250 DI 10.3189/172756403781816194 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BX30W UT WOS:000184905100033 ER PT S AU Joughin, IR Tulaczyk, S Engelhardt, HE AF Joughin, IR Tulaczyk, S Engelhardt, HE BE Raymond, CF TI Basal melt beneath Whillans Ice Stream and Ice Streams A and C, West Antarctica SO ANNALS OF GLACIOLOGY, VOL 36 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Fast Glacier Flow CY JUN 10-14, 2002 CL YAKUTAT, ALASKA SP Univ Alaska, US Natl Sci Fdn, US Natl Acronaut & Space Adm, Univ Alaska Fairbanks, Geophys Inst, Univ Alaska Fairbanks, Int Arctic Res Ctr, Arctic Res Consortium United States ID MASS-BALANCE; SURFACE TEMPERATURES; STAGNATION; MECHANICS; REGIONS; SHELF; RADAR; SHEET; MODEL AB We have used a recently derived map of the velocity of Whillans Ice Stream and Ice Streams A and C, West Antarctica, to help estimate basal melt. Ice temperature was modeled with a simple vertical advection-diffusion equation, "tuned" to match temperature profiles. We find that most of the melt occurs beneath the tributaries, where larger basal shear stresses and thicker ice favor greater melt (e.g. 10-20 mm a(-1)). The occurrence of basal freezing is predicted beneath much of the ice plains of Ice Stream C and Whillans Ice Stream. Modeled melt rates for when Ice Stream C was active suggest there was enough meltwater generated in its tributaries to balance basal freezing on its ice plain. Net basal melt for Whillans Ice Stream is greater due to less steep basal temperature gradients. Modeled temperatures on Whillans Ice Stream, however, were constrained by a single temperature profile at UpB. Basal temperature gradients for Whillans branch 1 and Ice Stream A may have conditions more similar to those beneath Ice Streams C and D, in which case, there may not be sufficient melt to sustain motion. This would be consistent with the steady deceleration of Whillans Ice Stream over the last few decades. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. RP Joughin, IR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ian@radar-sci.jpl.nasa.gov RI Joughin, Ian/A-2998-2008 OI Joughin, Ian/0000-0001-6229-679X NR 36 TC 31 Z9 31 U1 0 U2 7 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-31-8 J9 ANN GLACIOL PY 2003 VL 36 BP 257 EP 262 DI 10.3189/172756403781816130 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BX30W UT WOS:000184905100035 ER PT S AU Bindschadler, RA Vornberger, PL King, MA Padman, L AF Bindschadler, RA Vornberger, PL King, MA Padman, L BE Raymond, CF TI Tidally driven stick-slip motion in the mouth of Whillans Ice Stream, Antarctica SO ANNALS OF GLACIOLOGY, VOL 36 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Fast Glacier Flow CY JUN 10-14, 2002 CL YAKUTAT, ALASKA SP Univ Alaska, US Natl Sci Fdn, US Natl Acronaut & Space Adm, Univ Alaska Fairbanks, Geophys Inst, Univ Alaska Fairbanks, Int Arctic Res Ctr, Arctic Res Consortium United States ID WEST ANTARCTICA; MASS-BALANCE; GLACIER; DYNAMICS; BEHAVIOR; SHELVES; ALASKA; STRAIN; SPEED; TIDE AB We show that the ice plain in the mouth of Whillans Ice Stream (formerly Ice Stream B), Antarctica, moves by stick-slip motion. During a spring-tide period, rapid motions regularly occur near high tide and during falling tide. This correlation is weaker during a neap-tide period when the tidal magnitudes are less. Precise timing of these motion events suggests that they propagate through the region with a mean velocity of 88 m s(-1). We hypothesize that this speed is associated with the propagation of shear waves through a wet subglacial till. Motion events are also seen on more smoothly flowing floating ice. Event delays are very short between grounded and floating stations, suggesting the events propagate through the ice shelf as an elastic wave. We further hypothesize the events are caused by the interaction of a sticky bed, the accumulation of stored elastic strain through the compression of ice by upstream inflow, and tidal forcing. Motion events seem to be triggered either by reduction of vertical normal stresses at high tide or by the increase of shear stresses from sub-shelf ocean currents during falling tide. Event magnitudes are not related to the length of the preceding quiescent period, suggesting significant viscous dissipation within the till. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SAIC, Beltsville, MD 20705 USA. Univ Newcastle Upon Tyne, Dept Geomat, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. Earth & Space Sci, Seattle, WA 98102 USA. RP Bindschadler, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. RI King, Matt/B-4622-2008 OI King, Matt/0000-0001-5611-9498 NR 31 TC 37 Z9 37 U1 1 U2 5 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-31-8 J9 ANN GLACIOL PY 2003 VL 36 BP 263 EP 272 DI 10.3189/172756403781816284 PG 10 WC Geosciences, Multidisciplinary SC Geology GA BX30W UT WOS:000184905100036 ER PT S AU Vogel, SW Tulaczyk, S Joughin, IR AF Vogel, SW Tulaczyk, S Joughin, IR BE Raymond, CF TI Distribution of basal melting and freezing beneath tributaries of Ice Stream C: implication for the Holocene decay of the West Antarctic ice sheet SO ANNALS OF GLACIOLOGY, VOL 36 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Fast Glacier Flow CY JUN 10-14, 2002 CL YAKUTAT, ALASKA SP Univ Alaska, US Natl Sci Fdn, US Natl Acronaut & Space Adm, Univ Alaska Fairbanks, Geophys Inst, Univ Alaska Fairbanks, Int Arctic Res Ctr, Arctic Res Consortium United States ID MASS-BALANCE; SUBGLACIAL GEOLOGY; MODEL; FLOW; DEFORMATION; CONSTRAINTS; TEMPERATURE; MECHANICS; DYNAMICS; CLIMATE AB Ice-stream tributaries connect the relatively slow-moving interior of the West Antarctic ice sheet (WAIS) with the fast-flowing Siple Coast ice streams. Basal water underneath these ice streams reduces basal resistance and enables the fast motion of the ice. Basal melting being the only source for this water, it is important to include the distribution of basal melting and freezing into numerical models assessing the stability of the WAIS. However, it is very difficult to constrain its distribution from existing field observations. Past borehole observations confirmed the presence of a wet bed at Byrd Station in the WAIS interior and at different locations within Siple Coast ice streams. However, the recent discovery of a 12-25 m thick sediment-laden bubble-free basal ice layer at the UpC boreholes indicates that basal freezing is either currently occurring or had occurred upstream during the last glacial-interglacial cycle. We use a flowline model of ice thermodynamics to assess and quantify the spatial and temporal distribution of basal melting and freezing beneath Ice Stream C tributaries, taking into account the geothermal flux, shear heating and heat conduction away from the bed. Under the assumption that the ice was moving over a weak bed (tau(b)= 1-10 kPa) our model is able to reproduce a layer of frozenon ice similar in thickness to the UpC "sticky spot" basal ice layer. Increased basal melting in the early Holocene possibly could have initiated the Holocene decay of the WAIS, whereas increased freezing rates over the past few thousand years could have decreased the amount of basal water in the system, resulting in a strengthening of the bed. This is consistent with current force-budget calculations for ice-stream tributaries and with observed stoppages and slow-downs of ice streams. C1 Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vogel, SW (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, 1156 High St, Santa Cruz, CA 95064 USA. EM svogel@es.ucsc.edu RI Joughin, Ian/A-2998-2008; Vogel, Stefan/I-1963-2014; OI Joughin, Ian/0000-0001-6229-679X; Vogel, Stefan W./0000-0002-4350-7130 NR 46 TC 23 Z9 23 U1 0 U2 14 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-31-8 J9 ANN GLACIOL PY 2003 VL 36 BP 273 EP 282 DI 10.3189/172756403781816112 PG 10 WC Geosciences, Multidisciplinary SC Geology GA BX30W UT WOS:000184905100037 ER PT S AU Li, J Zwally, HJ Cornejo, C Yi, DH AF Li, J Zwally, HJ Cornejo, C Yi, DH BE Duval, P TI Seasonal variation of snow-surface elevation in North Greenland as modeled and detected by satellite radar altimetry SO ANNALS OF GLACIOLOGY, VOL 37 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Physical and Mechanical Processes om Ice in Relation to Glacier and Ice-Sheet Modelling CY AUG 25-30, 2002 CL Chamonix, FRANCE SP Int Glacier Soc, CNRS, European Space Agc, Reg Rhone Alpes ID FIRN DENSIFICATION; ICE-SHEET; INTERANNUAL VARIATIONS; MASS-BALANCE; FLUCTUATIONS AB Comparison of the distribution of seasonal variations in surface elevation derived from a firn-densification-elevation model with observed variations derived from ERS-1/-2 satellite radar altimetry shows close similarity in the patterns of the amplitude of the variations over the North Greenland ice sheet. The amplitudes of the seasonal variations decrease from west to east and from south to north, determined by the accumulation rate and the surface-temperature distribution pattern. Several methods of estimating the amplitude of the seasonal variation in the observations are compared, including the use of a three-frequency sinusoidal function derived from the modeled seasonal variation that is asymmetric. The resulting correlation coefficient between the observed amplitude, estimated with the three-frequency function, and the modeled amplitude is 0.66 and the slope is 0.7. Residual differences may be caused by interannual variability in accumulation and temperature and other approximations in the model. C1 NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Ocean & Ice Branch, Greenbelt, MD 20771 USA. RP Li, J (reprint author), NASA, Goddard Space Flight Ctr, Raytheon ITSS, Code 971, Greenbelt, MD 20771 USA. EM lijun@icesat2.gsfc.nasa.gov NR 12 TC 9 Z9 9 U1 0 U2 5 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-32-6 J9 ANN GLACIOL PY 2003 VL 37 BP 233 EP 238 DI 10.3189/172756403781815889 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BY73Q UT WOS:000189450700036 ER PT S AU Bougamont, M Tulaczyk, S Joughin, I AF Bougamont, M Tulaczyk, S Joughin, I BE Duval, P TI Numerical investigations of the slow-down of Whillans Ice Stream, West Antarctica: is it shutting down like Ice Stream C? SO ANNALS OF GLACIOLOGY, VOL 37 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Physical and Mechanical Processes om Ice in Relation to Glacier and Ice-Sheet Modelling CY AUG 25-30, 2002 CL Chamonix, FRANCE SP Int Glacier Soc, CNRS, European Space Agc, Reg Rhone Alpes ID SURFACE MASS-BALANCE; BASAL MECHANICS; WATER-PIRACY; STAGNATION; MARGIN; RETREAT; GLACIER; MELT AB We investigate whether the recent slow-down of Whillans Ice Stream (WIS), West Antarctica, may lead to its complete stoppage in the near future, using a numerical model. Basal resistance to ice-Stream motion is represented by a continuous till layer whose strength changes in response to basal melting and freezing. We implement a basal drainage system, which acts to hinder ice-stream stoppage through supply of extra water to those parts of the bed that arc experiencing freezing. The ice module is a standard flowline model with parameterized key out-of-plane effects (Raymond, 1996). The most important result of our modeling effort is that we never obtained a slow-down that would not be followed by a complete stoppage within <100 years. WIS slow-down can be avoided in the model if large basal water-input rates are assumed, to satisfy basal freezing. In comparison, the tested perturbations in WIS width and mass balance had a relatively small effect on the tendency of the simulated ice stream to slow down. These results underscore the need for more quantitative constraints on the efficiency of sub-ice-stream water drainage. We conjecture that the present-day slow-down of WIS will evolve to shut-down in the next few decades, unless an addition of basal water prevents freeze-on-driven bed strengthening. C1 Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95060 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bougamont, M (reprint author), Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95060 USA. EM marion@es.ucsc.edu RI Joughin, Ian/A-2998-2008; OI Joughin, Ian/0000-0001-6229-679X; Bougamont, Marion Heidi/0000-0001-7196-4171 NR 33 TC 32 Z9 32 U1 0 U2 5 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-32-6 J9 ANN GLACIOL PY 2003 VL 37 BP 239 EP 246 DI 10.3189/172756403781815555 PG 8 WC Geosciences, Multidisciplinary SC Geology GA BY73Q UT WOS:000189450700037 ER PT S AU Carsey, F Mogensen, CT Behar, A Engelhardt, H Lane, AL AF Carsey, F Mogensen, CT Behar, A Engelhardt, H Lane, AL BE Duval, P TI Science goals for a Mars polar-cap subsurface mission: optical approaches for investigations of inclusions in ice SO ANNALS OF GLACIOLOGY, VOL 37 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Physical and Mechanical Processes om Ice in Relation to Glacier and Ice-Sheet Modelling CY AUG 25-30, 2002 CL Chamonix, FRANCE SP Int Glacier Soc, CNRS, European Space Agc, Reg Rhone Alpes ID DUST CONCENTRATION; CORE; SCATTERING; CLIMATE AB The Mars polar caps are highly interesting features of Mars and have received much recent attention, with new and exciting data on morphology, basal units and layered outcroppings. We have examined the climatological, glaciological and geological issues associated with a subsurface exploration of the Mars North Polar Cap and have determined that a fine-scale optical examination of ice in a borehole, to study the stratigraphy, geochemistry and geochronology of the ice, is feasible. This information will enable reconstruction of the development of the cap as well as understanding the properties of its ice. We present visible imagery taken of dust inclusions in archived Greenland ice cores as well as in situ images of accreted lithologic inclusions in West Antarctica, and we argue for use of this kind of data for Mars climate reconstruction as has been successful with Greenland and Antarctic ice-core analysis. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Copenhagen, DK-2100 Copenhagen, Denmark. CALTECH, Pasadena, CA 91025 USA. RP Carsey, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM fcarsey@jpl.nasa.gov NR 21 TC 0 Z9 0 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-32-6 J9 ANN GLACIOL PY 2003 VL 37 BP 357 EP 362 DI 10.3189/172756403781816004 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BY73Q UT WOS:000189450700055 ER PT S AU Siegert, MJ Payne, AJ Joughin, I AF Siegert, MJ Payne, AJ Joughin, I BE Duval, P TI Spatial stability of Ice Stream D and its tributaries, West Antarctica, revealed by radio-echo sounding and interferometry SO ANNALS OF GLACIOLOGY, VOL 37 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Physical and Mechanical Processes om Ice in Relation to Glacier and Ice-Sheet Modelling CY AUG 25-30, 2002 CL Chamonix, FRANCE SP Int Glacier Soc, CNRS, European Space Agc, Reg Rhone Alpes ID SHEET; FLOW; RADAR; MODEL AB It has been shown recently that ice streams are fed by fast-flowing tributaries occupying well-defined subglacial troughs and with shared source areas. Here, ice-penetrating radio-echo sounding (RES) data are analyzed in conjunction with ice surface velocities derived from interferometric synthetic aperture radar (InSAR), to determine the englacial properties of tributaries feeding Ice Stream D, West Antarctica. All of Ice Stream D's tributaries are coincident with "buckled" internal ice-sheet layers, most probably deformed by the processes responsible for enhanced ice flow. Between the tributaries well-preserved internal layers occur. The data reveal that no lateral migration of the ice-stream tributaries has occurred recently. This is consistent with thermomechanical ice-flow modelling, which indicates that the flow of Ice Stream D is controlled by a subglacial trough and is unaffected by changes to the flow of neighbouring Ice Stream C. C1 Bristol Glaciol Ctr, Sch Geog Sci, Ctr Polar Observat & Med, Bristol, Avon, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Siegert, MJ (reprint author), Bristol Glaciol Ctr, Sch Geog Sci, Ctr Polar Observat & Med, Bristol, Avon, England. EM m.j.siegert@bristol.ac.uk RI Siegert, Martin/A-3826-2008; payne, antony/A-8916-2008; Joughin, Ian/A-2998-2008 OI Siegert, Martin/0000-0002-0090-4806; payne, antony/0000-0001-8825-8425; Joughin, Ian/0000-0001-6229-679X NR 20 TC 23 Z9 24 U1 0 U2 1 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-32-6 J9 ANN GLACIOL PY 2003 VL 37 BP 377 EP 382 DI 10.3189/172756403781816022 PG 6 WC Geosciences, Multidisciplinary SC Geology GA BY73Q UT WOS:000189450700058 ER PT S AU Wang, WL Zwally, HJ Hulbe, CL Siegert, MJ Joughin, I AF Wang, WL Zwally, HJ Hulbe, CL Siegert, MJ Joughin, I BE Duval, P TI Anisotropic ice flow leading to the onset of Ice Stream D, West Antarctica: numerical modelling based on the observations from Byrd Station borehole SO ANNALS OF GLACIOLOGY, VOL 37 SE ANNALS OF GLACIOLOGY LA English DT Article; Proceedings Paper CT International Symposium on Physical and Mechanical Processes om Ice in Relation to Glacier and Ice-Sheet Modelling CY AUG 25-30, 2002 CL Chamonix, FRANCE SP Int Glacier Soc, CNRS, European Space Agc, Reg Rhone Alpes ID EAST ANTARCTICA; POLAR ICE; LAW DOME; SHEET; GREENLAND; TRIBUTARIES; LAYERS; SOUTH; CAMP AB An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D, West Antarctica. One path is near the centre line of the main tributary to the ice stream, while the second passes by the Byrd Station borehole site. In this paper, we analyze the flow of the moderately last-flowing tributaries in terms of ice-fabric anisotropy and estimate the steady-state ice-flow regions with the compatible developed crystal orientation fabrics along two particle paths. Comparison between modelled isochrones and internal layers detected from radio-echo sounding surveys in the area is used to suggest that flow upstream of the onset to Ice Stream D appears to have been stable since at least the Last Glacial Maximum. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Ocean & Ice Branch, Greenbelt, MD 20771 USA. Portland State Univ, Dept Geol, Portland, OR 97207 USA. Univ Bristol, Sch Geog Sci, Bristol Glaciol Ctr, Bristol BS8 1SS, Avon, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, WL (reprint author), NASA, Goddard Space Flight Ctr, Code 971, Greenbelt, MD 20771 USA. EM weili@icesat2.gsfc.nasa.gov RI Siegert, Martin/A-3826-2008; Joughin, Ian/A-2998-2008 OI Siegert, Martin/0000-0002-0090-4806; Joughin, Ian/0000-0001-6229-679X NR 37 TC 4 Z9 4 U1 0 U2 2 PU INT GLACIOLOGICAL SOC PI CAMBRIDGE PA LENSFIELD RD, CAMBRIDGE CB2 1ER, ENGLAND SN 0260-3055 BN 0-946417-32-6 J9 ANN GLACIOL PY 2003 VL 37 BP 397 EP 403 DI 10.3189/172756403781815591 PG 7 WC Geosciences, Multidisciplinary SC Geology GA BY73Q UT WOS:000189450700061 ER PT S AU Zampino, EJ Millis, MG AF Zampino, EJ Millis, MG GP IEEE TI The potential application of risk assessment to the Breakthrough Propulsion Physics Project SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM, 2003 PROCEEDINGS SE PROCEEDINGS : ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 49th Annual Reliability and Maintainability Symposium (RAMS) CY JAN 27-30, 2003 CL TAMPA, FLORIDA SP IEEE, SAE, SLE, Soc Reliabil Engineers, IIE, IEST, AIAA, Syst Safety Soc, Amer Soc Qual, Electr Div, Amer Soc Qual, Reliabil Div DE success event; success tree; success tree analysis; defect detection and prevention; project success analysis; emerging science; ultra-reliability; ultra-maintainability; hypothetical-system availability analysis AB In May of 2001, researchers at the NASA Glenn Research center in Cleveland Ohio began exploring the possibility of applying Risk Assessment to a frontier propulsion project called Breakthrough Propulsion Physics (BPP). The goals of BPP are the drastic reduction or elimination of propellant mass, the attainment of hyper-fast space travel (approaching or exceeding) the speed of light, and new methods for on-board energy conversion. The BPP challenges transcend mere engineering and forces a re-examination of the fundamental physics from which technology is developed. Presently, BPP is at a maturity level of emerging science. The challenge is formidable: to apply risk assessment to a project that will not have conceptual designs for a long time to come. However, we suggest that it still makes a great deal of sense to think about the risks associated with various paths of research. In particular, it is suggested that there are a number of potential areas where Risk Assessment can be applied even when a project is at the maturity level of emerging science. It is believed that with the concepts and tools of Risk Assessment, more is possible than assessing potential reliability and maintainability. There is more to the story than the obvious need for greater Reliability. We are proposing that Risk Assessment Tools can be applied to guide research success. C1 NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Zampino, EJ (reprint author), NASA, Glenn Res Ctr Lewis Field, MS 50-4,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU I E E E PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0149-144X BN 0-7803-7717-6 J9 P A REL MAI PY 2003 BP 164 EP 169 DI 10.1109/RAMS.2003.1181920 PG 6 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BW46C UT WOS:000182081600027 ER PT S AU Baker, GH AF Baker, GH GP IEEE IEEE TI Reliability analysis of multi element integrated testing in space systems SO ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM, 2003 PROCEEDINGS SE Reliability and Maintainability Symposium LA English DT Article; Proceedings Paper CT 49th Annual Reliability and Maintainability Symposium (RAMS) CY JAN 27-30, 2003 CL TAMPA, FL SP IEEE, SAE, SLE, Soc Reliabil Engineers, IIE, IEST, AIAA, Syst Safety Soc, Amer Soc Qual, Electr Div, Amer Soc Qual, Reliabil Div DE hardware-software-human reliability; system reliability; interface reliability; integrated systems AB This paper presents the analyses of a methodology to capture quantitative reliability from multi element integrated systems of processing environments of the International Space Station (ISS) Program at the Kennedy Space Center (KSC) in Florida. The analysis uses the combination of Baker's Generic Classification Scheme, Goodness of Fit and the Laplace techniques to classify the multi-element integrated systems within processes into single (human, hardware, software), dual (hardware-software, software-human, human-hardware), and multi elements (hardware-software-human) interactions. The technique provides practitioners with immediate statistical significance of reliability growth or deterioration in a process. The significance of research lies within the inclusion of first order element interactions of dual and multi elements to properly estimate standard reliability. Qualitative and quantitative decisions are made to understand mechanisms across simulated and operationally configured tests (at the system, subsystem, element, element interaction, and element attributes levels) as well as scrutinize certain problems within steps of various sequenced processes. The analyses mark the first time a logically statistical technique is utilized in an integrated approach to assess total system reliability of simultaneous failures in real field performance. The overall reliability assessment reflects process success rate over the development test time. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP NASA, QA C KSC, Kennedy Space Ctr, FL 32899 USA. EM Gena.Baker-I@ksc.nasa.gov 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 0149-144X BN 0-7803-7717-6 J9 P REL MAINT S PY 2003 BP 574 EP 580 DI 10.1109/RAMS.2003.1182052 PG 7 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA BW46C UT WOS:000182081600094 ER PT J AU Crenshaw, DM Kraemer, SB George, IM AF Crenshaw, DM Kraemer, SB George, IM TI Mass loss from the nuclei of active galaxies SO ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS LA English DT Article DE Seyfert galaxies; quasars; outflow; intrinsic absorption; warm absorber ID QUASI-STELLAR OBJECTS; X-RAY-ABSORPTION; TELESCOPE IMAGING SPECTROGRAPH; NARROW-LINE REGION; SPECTROSCOPIC-EXPLORER-OBSERVATIONS; TRANSMISSION GRATING SPECTROMETER; HOPKINS-ULTRAVIOLET-TELESCOPE; XMM-NEWTON OBSERVATION; SEYFERT 1 GALAXIES; PHOTOIONIZATION CROSS-SECTIONS AB Blueshifted absorption lines in the UV and X-ray spectra of active galaxies reveal the presence of massive outflows of ionized gas from their nuclei. The "intrinsic" UV and X-ray absorbers show large global covering factors of the central continuum source, and the inferred mass loss rates are comparable to the mass accretion rates. Many absorbers show variable ionic column densities, which are attributed to a combination of variable ionizing flux and motion of gas into and out of the line of sight. Detailed studies of the intrinsic absorbers, with the assistance of monitoring observations and photoionization models, provide constraints on their kinematics, physical conditions, and locations relative to the central continuum source, which range from the inner nucleus (similar to0.01 pc) to the galactic disk or halo (similar to10 kpc). Dynamical models that make use of thermal winds, radiation pressure, and/or hydromagnetic flows have reached a level of sophistication that permits comparisons with the observational constraints. C1 Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Catholic Univ Amer, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. EM crenshaw@chara.gsu.edu; stiskraemer@yancey.gsfc.nasa.gov; ian.george@umbc.edu NR 229 TC 304 Z9 305 U1 0 U2 3 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4146 J9 ANNU REV ASTRON ASTR JI Annu. Rev. Astron. Astrophys. PY 2003 VL 41 BP 117 EP 167 DI 10.1146/annurev.astro.41.082801.100328 PG 51 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 742AX UT WOS:000186494000005 ER PT J AU Righter, K AF Righter, K TI Metal-silicate partitioning of siderophile elements and coreformation in the early Earth SO ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES LA English DT Review DE accretion; differentiation; mantle; equilibrium; planetary interiors ID FE-NI-S; SHERGOTTITE PARENT BODY; EARLY CORE FORMATION; HF-W CHRONOMETRY; DEEP MAGMA OCEAN; OXYGEN FUGACITY; HIGH-PRESSURE; TERRESTRIAL PLANETS; HIGH-TEMPERATURE; UPPER-MANTLE AB Accretion models for the Earth and terrestrial planets are based on the distribution of siderophile (iron-loving) elements between metal and silicate. Extensive experimental studies of the partitioning of these elements between metallic liquid and silicate melt have led to a better understanding and a more sophisticated application to planetary problems. Siderophile element metal/silicate partition coefficients are a function of temperature, pressure, oxygen fugacity, and metal and silicate composition. Quantification of these effects for a limited subset of siderophile elements has led to the idea that early Earth had a 700-km or deeper magma ocean. This new understanding of siderophile element partitioning has also led to applications to the kinetics of metal-silicate equilibrium, links to the timing of core formation, and a better understanding of core formation and metal-silicate equilibrium in the Moon and Mars. Key issues for future consideration include the role of water in early Earth, consideration of the core as a reservoir for noble gases and/or traditionally lithophile elements, siderophile element concentrations in the deep mantle, oxygen fugacity at high pressures, and further evaluation of the need for a late accretional veneer. The strongest approach to improving accretion models for the terrestrial planets is one that combines geochemistry, geophysics, and planetary dynamics. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Righter, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM kevin.righter-l@nasa.gov NR 158 TC 96 Z9 97 U1 4 U2 28 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0084-6597 J9 ANNU REV EARTH PL SC JI Annu. Rev. Earth Planet. Sci. PY 2003 VL 31 BP 135 EP 174 DI 10.1146/annurev.earth.31.100901.145451 PG 40 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Geology GA 717MN UT WOS:000185093700004 ER PT J AU Thomas, JL Diskin, B Brandt, A AF Thomas, JL Diskin, B Brandt, A TI Textbook multigrid efficiency for fluid simulations SO ANNUAL REVIEW OF FLUID MECHANICS LA English DT Review DE Navier-Stokes; Euler; discretization; solver; factorizability ID NAVIER-STOKES EQUATIONS; EULER EQUATIONS; DISCRETIZATIONS; CONVERGENCE; FLOWS AB Recent advances in achieving textbook multigrid efficiency for fluid simulations are presented. Textbook multigrid efficiency is defined as attaining the solution to the governing system of equations in a computational work that is a small multiple of the operation counts associated with discretizing the system. Strategies are reviewed to attain this efficiency by exploiting the factorizability properties inherent to a range of fluid simulations, including the compressible Navier-Stokes equations. Factorizability is used to separate the elliptic and hyperbolic factors contributing to the target system; each of the factors can then be treated individually and optimally. Boundary regions and discontinuities are addressed with separate (local) treatments. New formulations and recent calculations demonstrating the attainment of textbook efficiency for aerodynamic simulations are shown. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Weizmann Inst Sci, IL-76100 Rehovot, Israel. RP Thomas, JL (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 39 TC 27 Z9 27 U1 2 U2 8 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4189 J9 ANNU REV FLUID MECH JI Annu. Rev. Fluid Mech. PY 2003 VL 35 BP 317 EP 340 DI 10.1146/annurev.fluid.35.101101.161209 PG 24 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 646GX UT WOS:000181028200014 ER PT J AU Williams, DR AF Williams, DR TI The biomedical challenges of space flight SO ANNUAL REVIEW OF MEDICINE-SELECTED TOPICS IN THE CLINICAL SCIENCES LA English DT Review DE space medicine; evidence-based medicine; bioastronautics; physiological adaptation to space flight; pathophysiology of disease in space AB Space medicine has evolved considerably through past U.S. missions. It has been proven that humans can live and work in space for long durations and that humans are integral to mission success. The space medicine program of the National Aeronautics and Space Administration (NASA) looks toward future long-duration missions. Its goal is to overcome the biomedical challenges associated with maintaining the safety, health, and optimum performance of astronauts and cosmonauts. This program investigates the health effects of adaptation to microgravity: the nature of their pathologies, the effects of microgravity on pathophysiology, and the alterations in pharmacodynamics and treatment. A critical capability in performing research is the monitoring of the health of all astronauts and of the spacecraft environment. These data support the evidence-based approach to space medicine, incorporating past studies of microgravity-related conditions and their terrestrial counterparts. This comprehensive approach will enable safe and effective exploration beyond low Earth orbit. C1 NASA, Lyndon B Johnson Space Ctr, Space & Life Sci Directorate, Houston, TX 77058 USA. RP Williams, DR (reprint author), NASA, Lyndon B Johnson Space Ctr, Space & Life Sci Directorate, Houston, TX 77058 USA. NR 30 TC 23 Z9 26 U1 1 U2 7 PU ANNUAL REVIEWS PI PALO ALTO PA 4139 EL CAMINO WAY, PO BOX 10139, PALO ALTO, CA 94303-0139 USA SN 0066-4219 J9 ANNU REV MED JI Annu. Rev. Med. PY 2003 VL 54 BP 245 EP 256 DI 10.1146/annurev.med.54.101601.152215 PG 14 WC Medicine, General & Internal SC General & Internal Medicine GA 670WV UT WOS:000182433600015 PM 12471177 ER PT J AU Padman, L Erofeeva, S Joughin, I AF Padman, L Erofeeva, S Joughin, I TI Tides of the Ross Sea and Ross Ice Shelf cavity SO ANTARCTIC SCIENCE LA English DT Article; Proceedings Paper CT 2nd International Conference on the Ross Sea CY OCT, 2001 CL ISCHIA, ITALY SP CLIMA, PNRA DE altimetry; data assimilation; ice shelves; inverse modelling; mixing; synthetic aperture radar ID SOUTHERN WEDDELL SEA; INTERNAL TIDES; OCEAN TIDES; MODEL; STRATIFICATION; INTERFEROMETRY; BAROCLINICITY; ANTARCTICA; FILCHNER; WATER AB Two new ocean tide models for the Ross Sea including the ocean cavity under the Ross Ice Shelf, are described. The optimum model for predicting ice shelf surface height variability is based on assimilation of gravimetry-derived tidal constituents from the Ross Ice Shelf. Synthetic aperture radar interferograms provide an independent test of model performance. The standard deviation of tide height variability is largest under the eastern ice shelf along the Shirase and Siple Coasts, where it can exceed 0.8 m. The maximum peak-to-peak tidal range in this region is similar to3 m. The best predictor for ocean tidal currents north of the ice front is a dynamics-based model that solves the depth-integrated shallow water equations with a linear representation of benthic friction rather than the more usual quadratic form. Tidal currents over the open Ross Sea are dominated by diurnal, topographically trapped vorticity waves. The strongest modelled currents exceed 1 m s(-1) at spring tide in a narrow band along the upper continental slope in the north-westem Ross Sea. Typical tidal currents in the central continental shelf area of the Ross Sea are 10-20 cm s(-1). Under the ice shelf the typical currents are similar to5 cm s(-1). C1 Earth & Space Res, Seattle, WA 98102 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Jet Prop Lab, Pasadena, CA 91109 USA. RP Padman, L (reprint author), Earth & Space Res, 3350 SW Cascade Ave, Corvallis, OR 97333 USA. EM padman@esr.org RI Joughin, Ian/A-2998-2008 OI Joughin, Ian/0000-0001-6229-679X NR 34 TC 49 Z9 50 U1 0 U2 8 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4211 USA SN 0954-1020 J9 ANTARCT SCI JI Antarct. Sci. PD JAN PY 2003 VL 15 IS 1 BP 31 EP 40 DI 10.1017/S0954102003001032 PG 10 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 658BL UT WOS:000181701700005 ER PT J AU Bloomberg, JJ Mulavara, AP AF Bloomberg, JJ Mulavara, AP TI Understanding astronaut locomotor dysfunction after spaceflight: A sensorimotor perspective. SO ANTHROPOLOGICAL SCIENCE LA English DT Meeting Abstract C1 NASA, Johnson Space Ctr, Neurosci Labs, Houston, TX 77058 USA. EM jbloombe@ems.jsc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU ANTHROPOLOGICAL SOC NIPPON PI TOKYO PA C/O GALILEO INC, URBAN-OHTSUKA BLDG, 3RD FL, 3-21-10 KITA-OHTSUKA, TOSHIMA-KU, TOKYO, 170-0004, JAPAN SN 0918-7960 EI 1348-8570 J9 ANTHROPOL SCI JI Anthropol. Sci. PD JAN PY 2003 VL 111 IS 1 BP 73 EP 73 PG 1 WC Anthropology; Evolutionary Biology SC Anthropology; Evolutionary Biology GA 647LD UT WOS:000181093500087 ER PT S AU Kumei, Y Morita, S Shimokawa, H Ohya, K Akiyama, H Hirano, M Sams, CF Whitson, PA AF Kumei, Y Morita, S Shimokawa, H Ohya, K Akiyama, H Hirano, M Sams, CF Whitson, PA BE Diederich, M TI Inhibition of HSP70 and a collagen-specific molecular chaperone (HSP47) expression in rat osteoblasts by microgravity SO APOPTOSIS: FROM SIGNALING PATHWAYS TO THERAPEUTIC TOOLS SE ANNALS OF THE NEW YORK ACADEMY OF SCIENCES LA English DT Article; Proceedings Paper CT 5th International Conference on Apoptosis from Signalling Pathways to Therapeutic Tools CY JAN 29-FEB 01, 2003 CL LUXEMBOURG, LUXEMBOURG DE space flight; stress; osteoblast; HSP70; HSP47; HSC73; TGF-beta 1 ID STRESS AB Rat osteoblasts were cultured aboard a space shuttle for 4 or 5 days. Cells were exposed to 1alpha, 25 dihydroxyvitamin D-3 during the last 20 h and then solubilized by guanidine solution. The mRNA levels for molecular chaperones were analyzed by semi-quantitative RT-PCR. ELISA was used to quantify TGF-beta1 in the conditioned medium. The HSP70 mRNA levels in the flight cultures were almost completely suppressed, as compared to the ground (1 X g) controls. The inducible HSP70 is known as the major heat shock protein that prevents stress-induced apoptosis. The mean mRNA levels for the constitutive HSC73 in the flight cultures were reduced to 69%, similar to 60% of the ground controls. HSC73 is reported to prevent the pathological state that is induced by disruption of microtubule network. The mean HSP47 mRNA levels in the flight cultures were decreased to 50% and 19% of the ground controls on the 4th and 5th days. Concomitantly, the concentration of TGF-beta1 in the conditioned medium of the flight cultures was reduced to 37% and 19% of the ground controls on the 4th and 5th days. HSP47 is the collagen-specific molecular chaperone that controls collagen processing and quality and is regulated by TGF-beta1. Microgravity differentially modulated the expression of molecular chaperones in osteoblasts, which might be involved in induction and/or prevention of osteopenia in space. C1 Tokyo Med & Dent Univ, Grad Sch, Dept Hard Tissue Engn, Tokyo 1138549, Japan. Toray Res Ctr Ltd, Kamakura, Kanagawa 2488555, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Kumei, Y (reprint author), Tokyo Med & Dent Univ, Grad Sch, Dept Hard Tissue Engn, Tokyo 1138549, Japan. EM kumei.bch@tmd.ac.jp NR 7 TC 8 Z9 9 U1 0 U2 0 PU NEW YORK ACAD SCIENCES PI NEW YORK PA 2 EAST 63RD ST, NEW YORK, NY 10021 USA SN 0077-8923 BN 1-57331-474-9 J9 ANN NY ACAD SCI JI Ann.NY Acad.Sci. PY 2003 VL 1010 BP 476 EP 480 DI 10.1196/annals.1299.086 PG 5 WC Cell Biology; Medicine, Research & Experimental; Multidisciplinary Sciences SC Cell Biology; Research & Experimental Medicine; Science & Technology - Other Topics GA BY71U UT WOS:000189446300087 PM 15033773 ER PT J AU Kennedy, CA Carpenter, MH AF Kennedy, CA Carpenter, MH TI Additive Runge-Kutta schemes for convection-diffusion-reaction equations SO APPLIED NUMERICAL MATHEMATICS LA English DT Article ID DIFFERENTIAL-ALGEBRAIC SYSTEMS; IMPLICIT EXPLICIT METHODS; STARTING ALGORITHMS; NUMERICAL-SOLUTION; STIFF PROBLEMS; ERROR; IMPLEMENTATION; ORDER; ODES; STRATEGIES AB Additive Runge-Kutta (ARK) methods are investigated for application to the spatially discretized one-dimensional convection-diffusion-reaction (CDR) equations. Accuracy, stability, conservation, and dense-output are first considered for the general case when N different Runge-Kutta methods are grouped into a single composite method. Then, implicit-explicit, (N = 2), additive Runge-Kutta (ARK(2)) methods from third- to fifth-order are presented that allow for integration of stiff terms by an L-stable, stiffly-accurate explicit, singly diagonally implicit Runge-Kutta (ESDIRK) method while the nonstiff terms are integrated with a traditional explicit Runge-Kutta method (ERK). Coupling error terms of the partitioned method are of equal order to those of the elemental methods. Derived ARK(2) methods have vanishing stability functions for very large values of the stiff scaled eigenvalue, z([I]) --> -infinity, and retain high stability efficiency in the absence of stiffness, z([I]) --> 0. Extrapolation-type stage-value predictors are provided based on dense-output formulae. Optimized methods minimize both leading order ARK(2) error terms and Butcher coefficient magnitudes as well as maximize conservation properties. Numerical tests of the new schemes on a CDR problem show negligible stiffness leakage and near classical order convergence rates. However, tests on three simple singular-perturbation problems reveal generally predictable order reduction. Error control is best managed with a PID-controller. While results for the fifth-order method are disappointing, both the new third- and fourth-order methods are at least as efficient as existing ARK(2) methods. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. NASA, Langley Res Ctr, Aeronaut & Aeroacoust Methods Branch, Hampton, VA 23681 USA. RP Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. EM cakenne@ca.sandia.gov NR 77 TC 223 Z9 231 U1 4 U2 28 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 EI 1873-5460 J9 APPL NUMER MATH JI Appl. Numer. Math. PD JAN PY 2003 VL 44 IS 1-2 BP 139 EP 181 AR PII S0168-9274(02)00138-1 DI 10.1016/S0168-9274(02)00138-1 PG 43 WC Mathematics, Applied SC Mathematics GA 633ZD UT WOS:000180314200009 ER PT J AU Turyshev, SG AF Turyshev, SG TI Analytical modeling of the white-light fringe SO APPLIED OPTICS LA English DT Article ID PALOMAR TESTBED INTERFEROMETER; STELLAR INTERFEROMETRY AB An analytical technique for extracting phase, visibility, and amplitude information as needed for interferometric astrometry for the Space Interferometry Mission (SIM) is presented. This model accounts for a number of physical and instrumental effects and is valid for the general case of a bandpass filter. I was able to obtain a general solution for polychromatic phasors and to address the properties of unbiased fringe estimators in the presence of noise. For demonstration purposes I studied a rectangular bandpass filter with two different methods of optical path difference (OPD) modulation: stepping and ramping OPD modulation. A number of areas for further studies relevant to instrument design and simulations are outlined and discussed. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Turyshev, SG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM turyshev@pop.jpl.nasa.gov NR 20 TC 7 Z9 7 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 1 PY 2003 VL 42 IS 1 BP 71 EP 90 DI 10.1364/AO.42.000071 PG 20 WC Optics SC Optics GA 631LX UT WOS:000180170200009 PM 12518826 ER PT J AU Vander Wal, RL Berger, GM Ticich, TM AF Vander Wal, RL Berger, GM Ticich, TM TI Carbon nanotube synthesis in a flame using laser ablation for in situ catalyst generation SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article ID CO2-LASER VAPORIZATION; INDUCED INCANDESCENCE; GROWTH MECHANISMS; NANOFIBERS; DEPOSITION; DYNAMICS; HYDROGEN; NICKEL; TEMPERATURE; ATMOSPHERE AB Laser ablation of either Ni or Fe is used to create nanoparticles within a reactive flame environment for catalysis of carbon nanotubes (CNTs). Ablation of Fe in a CO-enriched flame produces single-walled nanotubes, whereas, ablation of Ni in an acetylene-enriched flame produces carbon nanofibers. These results illustrate that the materials for catalyst particle formation and CNT, SWNT or nanofiber, inception and growth in the aerosol phase can be supplied from separate sources; a metal-carbon mixture produced by condensation is not necessary. Both particle formation and CNT inception can begin from molecular species in a laser-ablation approach within the complex chemical environment of a flame. Moreover, SWNTs and nanofibers can be synthesized within very short timescales, of the order of tens of milliseconds. Finally, high-intensity pulsed laser light can destroy CNTs through either vaporization or coalescence induced by melting. C1 NASA, Glenn Res Ctr, NCMR, Cleveland, OH 44135 USA. Centenary Coll Louisiana, Dept Chem, Shreveport, LA 71134 USA. RP Vander Wal, RL (reprint author), NASA, Glenn Res Ctr, NCMR, MS 110-3 21000,Brookpk Rd, Cleveland, OH 44135 USA. EM randy@rvander.grc.nasa.gov NR 38 TC 16 Z9 16 U1 1 U2 13 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PY 2003 VL 77 IS 7 BP 885 EP 889 DI 10.1007/s00339-003-2196-3 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 731YY UT WOS:000185915100007 ER PT J AU Lee, H Rostovtsev, Y Bednar, CJ Javan, A AF Lee, H Rostovtsev, Y Bednar, CJ Javan, A TI From laser-induced line narrowing to electromagnetically induced transparency: closed system analysis SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID GROUP-VELOCITY; ATOMIC GAS; LIGHT; MEDIA; SPECTROSCOPY; INVERSION AB The laser-induced line-narrowing effect, discovered more than thirty years ago, can also be applied to recent studies in high resolution spectroscopy based on electromagnetically induced transparency. In this paper we first present a general form of the transmission width of electromagnetically induced transparency in a homogeneously broadened medium. We then analyze a Doppler broadened medium by using a lorentzian function as the atomic velocity distribution. The dependence of the transmission linewidth on the driving field intensity is discussed and compared to the laser-induced line-narrowing effect. This dependence can be characterized by a parameter which can be regarded as "the degree of optical pumping." C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Lee, H (reprint author), CALTECH, Jet Prop Lab, MS 126-347, Pasadena, CA 91109 USA. EM hwang.Lee@jpl.nasa.gov NR 29 TC 58 Z9 58 U1 0 U2 8 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD JAN PY 2003 VL 76 IS 1 BP 33 EP 39 DI 10.1007/s00340-002-1030-5 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA 770RM UT WOS:000188744700006 ER PT J AU Pelletier, MJ AF Pelletier, MJ TI Quantitative analysis using Raman spectrometry SO APPLIED SPECTROSCOPY LA English DT Review ID FOURIER-TRANSFORM-RAMAN; LEAST-SQUARES REGRESSION; LOCALLY WEIGHTED REGRESSION; NEAR-INFRARED SPECTROSCOPY; POSITIONED SPURIOUS EVENTS; MULTIVARIATE DATA-ANALYSIS; COUPLED-DEVICE DETECTORS; ELIMINATE SPIKE NOISE; REID VAPOR-PRESSURE; IR-FT RAMAN C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pelletier, MJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 251 TC 150 Z9 151 U1 8 U2 62 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 5320 SPECTRUM DRIVE SUITE C, FREDERICK, MD 21703 USA SN 0003-7028 EI 1943-3530 J9 APPL SPECTROSC JI Appl. Spectrosc. PD JAN PY 2003 VL 57 IS 1 BP 20A EP 42A PG 23 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 644DE UT WOS:000180902000002 PM 14610929 ER PT J AU Kagley, AN Snider, RG Krishnakumar, PK Casillas, E AF Kagley, AN Snider, RG Krishnakumar, PK Casillas, E TI Assessment of seasonal variability of cytochemical responses to contaminant exposure in the blue mussel Mytilus edulis (complex) SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID DIGESTIVE CELLS; PUGET-SOUND; LYSOSOMAL STRUCTURE; ENVIRONMENTAL CONTAMINANTS; PHYSIOLOGICAL ENERGETICS; CHEMICAL CONTAMINANTS; AROMATIC-HYDROCARBONS; LITTORINA-LITTOREA; CELLULAR-RESPONSES; WASHINGTON AB A selected suite of cytochemical parameters in Mytilus edulis are altered in response to field and laboratory exposure to chemical contaminants. These biomarkers include lysosomal stability, nicotinamide adenine dinucleotide phosphate (NADPH)-ferrihemoprotein reductase activity, liposfuscin deposition, and accumulation of lysosomal and cytoplasmic unsaturated neutral lipid. Normal variations in physiological processes (influenced by exogenous seasonal changes in temperature, salinity, food availability, etc.) may alter the sensitivity of these biomarkers to contaminant exposure. To address this issue, M. edulis (complex) were sampled monthly from a reference nonurban site (Coupeville, Penn Cove) and a polluted urban site (Seacrest, Elliott Bay) in Puget Sound, WA, for a period of 15 months. Physiological measurements including total length, total weight, somatic and mantle weights (an indication of gonadal development and reproductive status), condition index, and the presence or absence of hemic neoplasia (HN, or leukemia) were recorded. Significant differences in lysosomal stability, lysosomal and cytoplasmic unsaturated neutral lipids, lipofuscin deposition, and NADPH-ferrihemoprotein reductase activity in cells of the digestive gland or digestive tubules were generally found in mussels taken throughout the year from Seacrest compared to mussels sampled from Coupeville, consistent with exposure to chemical contaminants. No seasonally influenced suppression of the entire suite of parameters as measures of contaminant exposure was evident. Therefore these biomarkers can be used to evaluate contaminant exposure in mussels throughout the entire year. C1 Hatfield Marine Sci Ctr, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr,Environm Conservat Div, Newport, OR 97391 USA. Cent Marine Fisheries Res Inst, Res Ctr, Mangalore 575001, India. Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Kagley, AN (reprint author), Hatfield Marine Sci Ctr, Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr,Environm Conservat Div, Newport, OR 97391 USA. NR 47 TC 29 Z9 29 U1 0 U2 4 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD JAN PY 2003 VL 44 IS 1 BP 43 EP 52 DI 10.1007/S00244-002-1303-3 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 618GU UT WOS:000179411000006 PM 12434218 ER PT S AU Daud, T Zebulum, R Duong, T Ferguson, I Padgett, C Stoica, A Thakoor, A AF Daud, T Zebulum, R Duong, T Ferguson, I Padgett, C Stoica, A Thakoor, A BE Kaynak, O Alpaydin, E Oja, E Xu, L TI Speed enhancement with soft computing hardware SO ARTIFICAIL NEURAL NETWORKS AND NEURAL INFORMATION PROCESSING - ICAN/ICONIP 2003 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT Joint International Conference on Artificial Neural Networks (ICANN)/International on Neural Information Processing (ICONIP) CY JUN 26-29, 2002 CL ISTANBUL, TURKEY SP Bogazici Univ Fdn, USAF, European Off Aerosp Res & Dev, Turkish Sci & Tech Res Council AB During the past few years JPL has been actively involved in soft computing research encompassing theory, architecture, and electronic hardware. There are a host of soft computing applications that require orders of magnitude enhancement in speed compared to present day simulations on digital machines. For real-time computing this is made possible by selecting suitable algorithms, designing compatible architectures and implementing them in parallel processing hardware. A compact low-power hardware design for insitu applications uses a 3D-packaged artificial neural network (ANN) multi-chip module performing object classification and recognition with 10(12) multiply-sum operations per second (ops). Additionally, development on evolvable hardware (EHW) implemented on reconfigurable electronic hardware has shown exciting high-speed evolution of various digital and analog circuits. We review our work to demonstrate real-time processing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Daud, T (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 SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-40408-2 J9 LECT NOTES COMPUT SC PY 2003 VL 2714 BP 1049 EP 1056 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA BX47F UT WOS:000185378100125 ER PT B AU Feather, MS Menzies, T Connelly, JR AF Feather, MS Menzies, T Connelly, JR BE Azada, D TI Matching software practitioner needs to researcher activities SO ASIA-PACIFIC SOFTWARE ENGINEERING CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 10th Asia-Pacific Software Engineering Conference (APSEC 2003) CY DEC 10-12, 2003 CL CHIANG MAI, THAILAND SP Chulalongkorn Univ, Fac Engn, Dept Comp Engn, Chulalongkorn Univ, Fac Sci, Dept Math, Chiang Mai Univ, Khon Kaen Univ, King Mongkuts Inst Tech N Bank, Fac Informat Technol, Mahasarakham Univ, Fac Informat, Ratchathani Coll Technol, Silpakorn Univ, Fac Sci, Dept Math, Fac Sci & Technol, Dept Comp Sci, Thammasat Univ, Software Pk, UniNet AB We present an approach to matching software practitioners' needs to software researchers' activities. It uses an accepted taxonomical software classification scheme as intermediary, in terms of which practitioners express needs, and researchers express activities. A decision support tool is used to combine these expressions of needs/activities, and to assist in studying the implications of that combined knowledge. This enables identification of fruitful connections between researchers and practitioners, of areas of common interest among researchers, and practitioners, and of "gaps": areas of unfulfilled needs or unmotivated research. We discuss the software engineering underpinning this approach, illustrating its utility by reporting on experiments with a real-world dataset gathered front researchers and practitioners. We also suggest that this same approach would be applicable to understanding the distribution of interests represented by presenters and attendees of a conference such as APSEC. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Feather, MS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2011-1 PY 2003 BP 6 EP 16 DI 10.1109/APSEC.2003.1254353 PG 11 WC Computer Science, Software Engineering SC Computer Science GA BY37L UT WOS:000189126900001 ER PT S AU Ely, TA Bell, D AF Ely, TA Bell, D BE Lafontaine, JD DeLafontaine, J Treder, J Soyka, MT Sims, JA TI Sensitivity of Mars Network surface navigation to timing errors SO ASTRODYNAMICS 2003, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AIAA/AAS Astrodynamics Specialist Conference CY AUG 03-07, 2003 CL Big Sky, MT SP Amer Inst Aeronaut & Astronaut, AAS AB A key service of the Mars Network (MN) will be to provide Doppler tracking measurements between a Mars surface asset and a Mars Network orbiter that can be used to determine the location of the surface asset. A requirement of the Network is to provide tracking data of sufficient quality to enable position determination to better than 10 m (1-sigma) uncertainty. Numerous error sources impact the quality of this data, one of which is data time tag errors. This error manifests itself in the positioning process because the recorded time used to query orbital trajectories and the location of the surface asset in inertial space is different from the real time that the measurement was taken. This study will show that the surface asset positioning process is robust and relatively insensitive to these errors. Indeed, the combination of in-situ and MN orbiter to Earth Doppler data is capable of simultaneously resolving surface asset and MN orbiter positions to an accuracy of 10 m, and clock errors to levels better than 3 msec. C1 CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, Pasadena, CA 91109 USA. RP Ely, TA (reprint author), CALTECH, Jet Prop Lab, Navigat & Miss Design Sect, 4800 Oak Grove Dr,MS 301-125L, Pasadena, CA 91109 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-509-1 J9 ADV ASTRONAUT SCI PY 2003 VL 116 BP 407 EP 427 PN 1-3 PG 21 WC Engineering, Aerospace SC Engineering GA BAK80 UT WOS:000222653500025 ER PT S AU Marr, GC AF Marr, GC BE Lafontaine, JD DeLafontaine, J Treder, J Soyka, MT Sims, JA TI Orbit determination (OD) error analysis results for the triana sun-earth L1 libration point mission and for the Fourier Kelvin Stellar Interferometer (FKSI) Sun-Earth L2 Libration point mission concept SO ASTRODYNAMICS 2003, PTS 1-3 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AIAA/AAS Astrodynamics Specialist Conference CY AUG 03-07, 2003 CL Big Sky, MT SP Amer Inst Aeronaut & Astronaut, AAS AB The Triana spacecraft was designed to be launched by the Space Shuttle. The nominal Triana mission orbit will be a Sun-Earth L1 Libration point orbit. Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination (OD) error analysis results are presented for all phases of the Triana mission from the first correction maneuver through approximately launch plus 6 Months. Results are also presented for the science data collection phase of the Fourier Kelvin Stellar Interferometer Sun-Earth L2 libration point mission concept with momentum unloading thrust perturbations during the tracking arc. The Triana analysis includes extensive analysis of an initial short arc orbit determination solution and results using both Deep Space Network (DSN) and commercial Universal Space Network (USN) statistics. These results could be utilized in support of future Sun-Earth libration point missions. C1 NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. RP Marr, GC (reprint author), NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Code 595, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-509-1 J9 ADV ASTRONAUT SCI PY 2003 VL 116 BP 475 EP 486 PN 1-3 PG 12 WC Engineering, Aerospace SC Engineering GA BAK80 UT WOS:000222653500029 ER EF