FN Thomson Reuters Web of Science™ VR 1.0 PT B AU Guhathakurta, M Fisher, R Strong, K AF Guhathakurta, M Fisher, R Strong, K BE Watanabe, T Kosgugi, T Sterling, AC TI Density, temperature and magnetic field structure of high latitude corona SO OBSERVATIONAL PLASMA ASTROPHYSICS: FIVE YEARS OF YOHKOH AND BEYOND SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Meeting Abstract CT Yohkoh 5th Anniversary Symposium on Observational Plasma Astrophysics - 5 Years of Yohkoh and Beyond CY NOV 06-08, 1996 CL TOKYO, JAPAN C1 Catholic Univ Amer, GSFC, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4985-7 J9 ASTROPHYS SPACE SC L PY 1998 VL 229 BP 13 EP 13 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK92W UT WOS:000073874900002 ER PT B AU Martens, PC AF Martens, PC BE Watanabe, T Kosgugi, T Sterling, AC TI SOHO-Yohkoh science collaboration SO OBSERVATIONAL PLASMA ASTROPHYSICS: FIVE YEARS OF YOHKOH AND BEYOND SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Yohkoh 5th Anniversary Symposium on Observational Plasma Astrophysics - 5 Years of Yohkoh and Beyond CY NOV 06-08, 1996 CL TOKYO, JAPAN C1 NASA, Goddard Space Flight Ctr, ESA, SSD, Greenbelt, MD 20771 USA. RP Martens, PC (reprint author), NASA, Goddard Space Flight Ctr, ESA, SSD, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4985-7 J9 ASTROPHYS SPACE SC L PY 1998 VL 229 BP 217 EP 225 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK92W UT WOS:000073874900036 ER PT B AU Martens, PCH Fletcher, L AF Martens, PCH Fletcher, L BE Watanabe, T Kosgugi, T Sterling, AC TI Hard X-ray emission from a mirror trap at the top of reconnecting loops SO OBSERVATIONAL PLASMA ASTROPHYSICS: FIVE YEARS OF YOHKOH AND BEYOND SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT Yohkoh 5th Anniversary Symposium on Observational Plasma Astrophysics - 5 Years of Yohkoh and Beyond CY NOV 06-08, 1996 CL TOKYO, JAPAN C1 NASA, Goddard Space Flight Ctr, ESA, SSD, Greenbelt, MD 20771 USA. RP Martens, PCH (reprint author), NASA, Goddard Space Flight Ctr, ESA, SSD, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4985-7 J9 ASTROPHYS SPACE SC L PY 1998 VL 229 BP 269 EP 271 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK92W UT WOS:000073874900043 ER PT B AU McDonald, KR Pfister, RG AF McDonald, KR Pfister, RG GP MTS MTS TI Access to ocean data through NASA's EOS data and information system SO OCEAN COMMUNITY CONFERENCE'98: CELEBRATING 1998 INTERNATIONAL YEAR OF THE OCEAN, PROCEEDINGS VOLS 1 AND 2 LA English DT Proceedings Paper CT Marine-Technology-Society Annual Conference CY NOV 16-19, 1998 CL BALTIMORE, MD SP Marine Technol Soc AB In support of the general Earth science research community, NASA has undertaken the development of the Earth Observing System Data and Information System (EOSDIS). Today, an early prototype of this system has been operating for over four years and the next version is in the integration and test stage. The approximately 750 data sets accessible through EOSDIS today cover the full spectrum of Earth science disciplines and include a rich collection of ocean science data. Future flight missions and related field programs will greatly enhance these data resources. In support of the production and archive of these data products, the EOSDIS project has established and used data and information standards, which in turn enable and facilitate the access and use of the data by the Earth science data user community. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McDonald, KR (reprint author), NASA, Goddard Space Flight Ctr, Code 423, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC PI WASHINGTON PA 1828 L ST NW,SUITE 906, WASHINGTON, DC 20035 USA BN 0-933957-21-1 PY 1998 BP 50 EP 54 PG 5 WC Engineering, Marine; Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing SC Engineering; Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing GA BP21L UT WOS:000084418300011 ER PT B AU Eplee, RE Robinson, WD Schieber, BD Barnes, RA McClain, CR Darzi, M AF Eplee, RE Robinson, WD Schieber, BD Barnes, RA McClain, CR Darzi, M GP MTS MTS TI SeaWiFS: Instrument status and project activities SO OCEAN COMMUNITY CONFERENCE'98: CELEBRATING 1998 INTERNATIONAL YEAR OF THE OCEAN, PROCEEDINGS VOLS 1 AND 2 LA English DT Proceedings Paper CT Marine-Technology-Society Annual Conference CY NOV 16-19, 1998 CL BALTIMORE, MD SP Marine Technol Soc ID ATMOSPHERIC CORRECTION; OCEANS RP Eplee, RE (reprint author), NASA, Goddard Space Flight Ctr, Code 9702, Greenbelt, MD 20771 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC PI WASHINGTON PA 1828 L ST NW,SUITE 906, WASHINGTON, DC 20035 USA BN 0-933957-21-1 PY 1998 BP 571 EP 575 PG 5 WC Engineering, Marine; Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing SC Engineering; Meteorology & Atmospheric Sciences; Oceanography; Remote Sensing GA BP21L UT WOS:000084418300113 ER PT S AU Ansari, RR Datiles, MB King, JF Leftwood, D AF Ansari, RR Datiles, MB King, JF Leftwood, D BE Rol, PO Joos, KM Manns, F TI Measuring lens opacity: combining quasi-elastic light scattering with Scheimpflug imaging system SO OPHTHALMIC TECHNOLOGIES VIII, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ophthalmic Technologies VIII CY JAN 24-25, 1998 CL SAN JOSE, CA SP USAF, Off Sci Res, Int Biomed Opt Soc, Soc Photo Opt Instrumentat Engineers AB Two powerful techniques: quasi-elastic light scattering (QELS) and Scheimpflug imaging (SI), are combined to provide simultaneous (within a few seconds) and objective measurements of lens opacity. The sensitivity and performance of the two techniques is evaluated by inducing cold cataract in the lens of a calf eye. The QELS detects the onset of cataractogenesis much earlier while the Scheimpflug imaging system detects it much later. C1 NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids & Combust Sci, Cleveland, OH 44135 USA. RP Ansari, RR (reprint author), NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids & Combust Sci, 21000 Brookpark Rd,Mail Stop 333-1, Cleveland, OH 44135 USA. OI Datiles, Manuel III B./0000-0003-4660-1664 NR 0 TC 7 Z9 7 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 0-8194-2685-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3246 BP 35 EP 42 DI 10.1117/12.309433 PG 8 WC Engineering, Biomedical; Ophthalmology; Optics SC Engineering; Ophthalmology; Optics GA BL20A UT WOS:000074660600005 ER PT S AU Wu, TK AF Wu, TK BE Armenise, MN Pecorella, W Sadovnik, LS TI Multiband frequency selective surface SO OPTICAL DEVICES AND METHODS FOR MICROWAVE/MILLIMETER-WAVE AND FRONTIER APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Devices and Methods for Microwave/Millimeter-Wave and Frontier Applications CY JUL 22-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE quasi-optics; dichroic; frequency selective surface; gratings; grids; Cassegrain antenna; dielectrics; filters AB This paper addresses the similarity of microwave/millimeter wave frequency selective surfaces (FSS) to optical filters. Specifically, the design approaches of the 4-band FSSs developed for NASA's CASSINI high gain antenna are described in detail. Representative RF test results are given to demonstrate the validity of these designs. These design approaches are very general and can be applied to multiband optical filters. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wu, TK (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 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 0-8194-2919-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3464 BP 174 EP 182 DI 10.1117/12.323140 PG 9 WC Optics SC Optics GA BL85M UT WOS:000076936500019 ER PT S AU Cwik, TA Fernandez, S Ksendzov, A La Baw, CC Maker, PD Muller, RE AF Cwik, TA Fernandez, S Ksendzov, A La Baw, CC Maker, PD Muller, RE BE Armenise, MN Pecorella, W Sadovnik, LS TI Design of multi-bandwidth frequency selective surfaces for near infrared filtering SO OPTICAL DEVICES AND METHODS FOR MICROWAVE/MILLIMETER-WAVE AND FRONTIER APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Devices and Methods for Microwave/Millimeter-Wave and Frontier Applications CY JUL 22-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE frequency selective surfaces; infrared filters; electromagnetic modeling; imaging spectroscopy; wedge filter AB This paper describes the design of infrared filters using methods drawn fi om microwave and millimeter wave filters. Special note is made of approximations made in the infrared design, and ways to improve upon these approximations. Results from the design, manufacture and test of linear wedge filters built using microlithographic techniques and used in spectral imaging applications will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cwik, TA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 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 0-8194-2919-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3464 BP 183 EP 193 DI 10.1117/12.323141 PG 11 WC Optics SC Optics GA BL85M UT WOS:000076936500020 ER PT S AU Leviton, DB Madison, TJ Petrone, P AF Leviton, DB Madison, TJ Petrone, P BE Datla, RV Hanssen, LM TI Simple refractometers for index measurements by minimum deviation method from far ultraviolet to near infrared SO OPTICAL DIAGNOSTIC METHODS FOR INORGANIC TRANSMISSIVE MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostic Methods for Inorganic Transmissive Materials CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE refractometer; refractometry; minimum deviation; focal shift; color filter glass; deviation angle AB The focal shift of an optical filter used in non-collimated light depends directly on substrate thickness and index of refraction. The HST Advanced Camera for Surveys (ACS) requires a set of filters whose focal shifts are tightly matched. Knowing the index of refraction for substrate glasses allows precise substrate thicknesses to be specified. Two refractometers have been developed at the Goddard Space Flight Center (GSFC) to determine the indices of refraction of materials from which ACS filters are made. Modern imaging detectors for the near infrared, visible, and far ultraviolet spectral regions make these simple yet sophisticated refractometers possible. A new technology, high accuracy, angular encoder also developed at GSFC makes high precision index measurement possible in the vacuum ultraviolet by prism methods. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 1 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 0-8194-2880-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3425 BP 148 EP 159 DI 10.1117/12.326672 PG 12 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BM03R UT WOS:000077457500017 ER PT S AU Leviton, DB Petrone, P AF Leviton, DB Petrone, P BE Datla, RV Hanssen, LM TI Variations in refractive index of color filter glasses SO OPTICAL DIAGNOSTIC METHODS FOR INORGANIC TRANSMISSIVE MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostic Methods for Inorganic Transmissive Materials CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE color filter glass; index of refraction; focal shift; prism; melt variation AB The focal shifts through optical bandpass filters built an color filter glass (CFG) substrates depend directly on substrate thickness and index of refraction. The filter set for I-IST Advanced Camera for Surveys (ACS) must have very tightly matched focal shifts. Knowing the index of refraction far substrate glasses allows precise substrate thicknesses to be specified. Unfortunately, index data is not provided by the glass manufacturer to the precision required to achieve adequately matched focal shifts. Therefore, the raw CFG materials for filters must be treated as unknowns with regard to refractive index. Using a simple yet accurate refractometer built at Goddard Space Flight Center (GSFC), indices of refraction were measured for approximately 30 different melts of CFG's from which ACS filters are made. In this paper, the process by which filters were made to have matched focal shifts is outlined, a compendium of all measured CFG index data is presented, and the variations of measured index from melt to melt of the same types of glasses are discussed and measured values compared to catalog values. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 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 0-8194-2880-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3425 BP 213 EP 218 DI 10.1117/12.326673 PG 6 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BM03R UT WOS:000077457500024 ER PT S AU Leviton, DB Madison, TJ Petrone, P AF Leviton, DB Madison, TJ Petrone, P BE Datla, RV Hanssen, LM TI Far ultraviolet refractive index of optical materials for Solar Blind Channel (SBC) filters for HST Advanced Camera for Surveys (ACS) SO OPTICAL DIAGNOSTIC METHODS FOR INORGANIC TRANSMISSIVE MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostic Methods for Inorganic Transmissive Materials CY JUL 20-21, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE minimum deviation method; index of refraction; far ultraviolet; calcium fluoride; fused silica; sapphire; barium fluoride; lithium fluoride AB Refractive index measurements using the minimum deviation method have been carried out for prisms of a variety of far ultraviolet optical materials used in the manufacture of Solar Blind Channel (SBC) filters for the HST Advanced Camera for Surveys (ACS). Some of the materials measured are gaining popularity in a variety of high technology applications including high power excimer lasers and advanced microlithography optics operating in a wavelength region where high quality knowledge of optical material properties is sparse yet critical. Our measurements are of unusually high accuracy and precision for this wavelength region owing to advanced instrumentation in the large vacuum chamber of the Diffraction Grating Evaluation Facility (DGEF) at Goddard Space Flight Center (GSFC) used to implement a minimum deviation method refractometer. Index values for CaF2, BaF2 LiF, and far ultraviolet grades of synthetic sapphire and synthetic fused silica are reported and compared with values from the literature. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 7 Z9 7 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 0-8194-2880-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3425 BP 219 EP 230 DI 10.1117/12.326675 PG 12 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Optics SC Materials Science; Optics GA BM03R UT WOS:000077457500025 ER PT S AU Ansari, RR Gray, GR Ling, J Knight, J AF Ansari, RR Gray, GR Ling, J Knight, J BE Priezzhev, AV Asakura, T Briers, JD Katzir, A TI Evaluation of incoherent light mixing effects on the quality of DLS data in a fiber optic set-up for biological fluids and tissues SO OPTICAL DIAGNOSTICS OF BIOLOGICAL FLUIDS III, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Diagnostics of Biological Fluids III CY JAN 28-29, 1998 CL SAN JOSE, CA SP Int Biomed Opt Soc, Soc Photo Opt Instrumentat Engineers AB Dynamic light scattering (DLS) measurements are mostly performed in dark rooms. Flare and external lights must be avoided in the design of such systems. Recent advancements in optoelectronic devices and fiber optic technology has opened up applications of DLS in areas where a few years ago, their use could not be imagined. We present a compact and flexible fiber optic DLS system with optical viewing (imaging) capability to monitor biological fluids and tissues in-vivo or in-situ in real time. The optical port requires white light illumination for sample viewing or video linking. An evaluation of the effects of mixing white illumination photons with launched coherent (red) photons on the DLS data will be made. Effects such as spatial coherence factors and the reliability in determining accurate particle size from such measurements are evaluated. C1 NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids & Combust Sci, Cleveland, OH 44135 USA. RP Ansari, RR (reprint author), NASA, Lewis Res Ctr, Natl Ctr Micrograv Res Fluids & Combust Sci, 21000 Brookpk Rd,Mail Stop 333-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 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 0-8194-2691-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3252 BP 84 EP 89 DI 10.1117/12.311879 PG 2 WC Engineering, Biomedical; Medical Laboratory Technology; Optics SC Engineering; Medical Laboratory Technology; Optics GA BL26T UT WOS:000074939500009 ER PT J AU Reid, MB Ozcan, M AF Reid, MB Ozcan, M TI Temperature dependence of fiber optic Bragg gratings at low temperatures SO OPTICAL ENGINEERING LA English DT Article DE fiber optic sensors; Bragg gratings; thermo-optic effect; refractive index of fused silica AB The temperature dependence of the Bragg wavelength of fiber optic gratings was measured at temperatures from 4.2 to 350 K. The measured wavelength dependence at room temperature (293 K) corresponds to a refractive index dependence of dn/dT=9.1X10(-6)/degrees C, which agrees with earlier results for fused silica. However, dn/dT decreases with lower temperatures, declining to 3.5X10(-6)/degrees C at liquid nitrogen temperature (77 K), and to approximately zero at liquid helium temperature (4.2 K). The Bragg wavelength of a fiber grating embedded in a composite material displayed the same temperature dependence as a non-embedded grating. (C) 1998 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(98)03901-4]. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Reid, MB (reprint author), NASA, Ames Res Ctr, Mail Stop 269-3, Moffett Field, CA 94035 USA. NR 10 TC 61 Z9 69 U1 1 U2 6 PU SPIE - INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING PI BELLINGHAM PA POB 10, BELLINGHAM, WA 98227-0010 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JAN PY 1998 VL 37 IS 1 BP 237 EP 240 DI 10.1117/1.601610 PG 4 WC Optics SC Optics GA YV001 UT WOS:000071778500034 ER PT S AU Chao, TH Reyes, G Park, YC Collins, D AF Chao, TH Reyes, G Park, YC Collins, D BE Casasent, DP Chao, TH TI Real-time adaptive optical joint transform correlator SO OPTICAL PATTERN RECOGNITION IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition IX CY APR 14-15, 1998 CL ORLANDO, FL SP SPIE, Int Soc Opt Engn AB A real-time optical joint transform correlator (OJTC) has been developed for direct-input optical correlation operation. Innovative features of this OJTC include: (1) two separate spatial light modulators, one for large-frame video rate input, the other for high-speed reference updating; and (2) a multiple quantum well holographic device (MQHD) for high-speed joint transform power spectrum detection and read-out. These system innovations have enabled real-time adaptive optical joint transform correlation to accommodate scale, rotation, and other variations required for real-world pattern recognition applications. System architecture and analysis will be depicted. Experimental results of invariant landmark tracking using this OJTC will be provided. 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 0 TC 0 Z9 0 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 0-8194-2835-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3386 BP 45 EP 49 DI 10.1117/12.304788 PG 5 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BK81F UT WOS:000073468900005 ER PT S AU Chao, TH Reyes, G Park, YC AF Chao, TH Reyes, G Park, YC BE Casasent, DP Chao, TH TI Gray scale optical correlator SO OPTICAL PATTERN RECOGNITION IX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Pattern Recognition IX CY APR 14-15, 1998 CL ORLANDO, FL SP SPIE, Int Soc Opt Engn AB A compact (Camcorder size), ultrahigh-speed, grayscale optical correlator capable of using grayscale input and real-valued correlation filter is reported. The unique bipolar-amplitude correlation filter modulation capability has enabled the direct implementation of composite filter algorithm such as MACH [8]. The direct usage of grayscale input also eliminated the need of image preprocessing (e.g. Sober filtering used for binary optical correlator). System architecture of this grayscale optical correlator will be described. Experimental results obtained using optically implemented MACH filter, for the first time, will also be provided. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Chao, TH (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 11 Z9 11 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 0-8194-2835-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3386 BP 60 EP 64 DI 10.1117/12.304790 PG 5 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BK81F UT WOS:000073468900007 ER PT S AU Schwemmer, G Wilkerson, T Guerra, D AF Schwemmer, G Wilkerson, T Guerra, D BE Singh, UN Hu, H Wang, G TI Compact scanning lidar systems using holographic optics SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc DE lidar; scanning; holographic optics; scanning telescopes; atmospheric winds AB Two scanning lidar systems have been built using holographic optical elements (HOE) that function as a scanning telescope primary optic. One is a ground based lidar using a reflection HOE, and uses a frequency doubled Nd:YAG laser transmitter. The other system is an airborne/ground based system that uses a transmission HOE and operates at the 1064nm fundamental of the Nd:YAG laser. Each HOE has a focal spot on the center-line, normal to the flat disk holding the hologram, and a field of view (FOV) that points approximately 45 degrees from the normal. Rotating the disk effects a conical scan of the FOV. In both systems, the same HOE is also used to collimate and steer the transmitted laser beam. The utility of using the HOEs to save weight and size in scanning lidars is evidenced by the atmospheric backscatter data collected with these systems. They also will lower the cost of commercial systems due to the low cost of replicating HOEs and the simplified mechanical scanning systems. Development of airborne scanning lidar altimeters and other lidars and passive instruments using holographic optics are underway, including the development of a one meter diameter, space qualified holographic scanning telescope for use in the ultraviolet. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Schwemmer, G (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 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 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 51 EP 59 DI 10.1117/12.319559 PG 9 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900008 ER PT S AU McDermid, IS Beyerle, G Haner, D Walsh, TD AF McDermid, IS Beyerle, G Haner, D Walsh, TD BE Singh, UN Hu, H Wang, G TI Redesign and improved performance of the JPL-TMF tropospheric lidars SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc DE lidar; ozone; aerosols AB We describe improvements to two lidar systems for measurements of ozone and aerosols in the troposphere and lower stratosphere. These changes are primarily related to the receiver optical sub-systems and the principal topics presented are the telescopes, the ozone DIAL receiver, and the aerosol lidar receiver. The data acquisition systems were also replaced. The goals of these modifications were to increase the spatial and temporal resolution of the lidars, to extend the altitude range covered, and to improve the quality of the raw data. C1 CALTECH, Jet Prop Lab, Table Mt Facil, Wrightwood, CA 92397 USA. RP McDermid, IS (reprint author), CALTECH, Jet Prop Lab, Table Mt Facil, POB 367, Wrightwood, CA 92397 USA. NR 0 TC 0 Z9 0 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 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 60 EP 66 DI 10.1117/12.319558 PG 7 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900009 ER PT S AU Butler, CF Browell, EV Fenn, MA Grant, W Clayton, M AF Butler, CF Browell, EV Fenn, MA Grant, W Clayton, M BE Singh, UN Hu, H Wang, G TI Ozone and aerosol distributions in the Pacific as observed by NASA's airborne UV DIAL system SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc DE DIAL (Differential absorption lidar); ozone; aerosols; Pacific distributions AB The NASA Langley Research Center's Airborne UV DIAL system has been flown on many tropospheric and stratospheric field campaigns since 1980. The current system, in its tropospheric configuration, transmits four beams in both nadir and zenith directions making measurements of O-3 and aerosols from near the surface to above the tropopause. This system has been flown on the NASA DC-X during the Global Tropospheric Experiments (GTE) to provide real-time remote sensing of tropopause heights, stratospheric intrusions, cloud tops/bases, boundary layer heights, and, in general, the large-scale variations of O-3 and aerosol distributions across the troposphere. In addition, post-mission analyses of relative amounts of ozone O-3 and aerosols as compared to discriminator profiles of each, permits an airmass characterization scheme including stratospherically influenced air, plumes with either high O-3 or high aerosols or both, continental outflows, convective transport, and clean marine air. During the missions the DIAL instrument is routinely used to identify altitudes of O-3 and/or aerosol layers so that the aircraft can then be directed to fly subsequent legs at specified heights to allow for in situ sampling of key species. In post-mission analyses the DIAL measurements provide the broader context for the in situ measurements of other trace species and, when coupled with meteorological and trajectory analyses, play a vital role in the interpretation of the dynamics and photochemistry of the troposphere. To date, NASA's GTE program has conducted three exploratory missions over the Pacific Ocean. PEM West-A (September-October 1991) and PEM West-B (February-March 1994) were focused in the western Pacific of the northern hemisphere to investigate the budget of O-3 and its precursors and to assess both the natural and anthropogenic impact of key atmospheric trace species in this region. PEM West-A was staged in late summer/early fall when the airflow is dominated by easterly across the Pacific. The second phase, PEM West-B, was staged during late winter when the airflow is characterized by maximum outflow from the Asian continent. PEM Tropics-A (September-October 1994) involved two NASA aircraft in a study of the chemistry of the troposphere over the central and southern Pacific with a focus on the tropics in the southern hemisphere. The intent was to study one of the few remaining clean air regions of the world to better understand the role of nitrogen oxides in the O-3 budget. A follow-up to this study, PEM Tropics-B, is in the process of being planned for February-April 1999 in a contrasting meteorological regime. Selected O-3 and aerosol distributions are illustrated from each of these field campaigns showing some of the key features in each experiment as observed by the airborne UV DIAL system. C1 Sci Applicat Int Corp, NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Butler, CF (reprint author), Sci Applicat Int Corp, NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. OI Grant, William/0000-0002-1439-3285 NR 0 TC 0 Z9 0 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 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 174 EP 181 DI 10.1117/12.319564 PG 8 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900024 ER PT S AU Karyampudi, VM Palm, SP Reagan, JA Fang, H Grant, WB Moulin, C Pierce, HF Browell, EV Melfi, SH AF Karyampudi, VM Palm, SP Reagan, JA Fang, H Grant, WB Moulin, C Pierce, HF Browell, EV Melfi, SH BE Singh, UN Hu, H Wang, G TI Validation of LITE-derived Saharan dust layer characteristics SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc DE LITE backscatter profiles; Meteosat data; Saharan dust; aerosol optical depths AB Lidar observations from the Lidar-in Space Technology Experiment (LITE), in conjunction with European Center for Medium Range Weather Forecasting (ECMWF) and Meteosat data were used to examine the Saharan dust characteristics including its structure, evolution and optical depths over Western Africa and E. Atlantic regions. The lidar backscatter profiles reveal a complex structure of the dust layer but, in general, show a good agreement with the features depicted in the conceptual model of the dust plume. Optical depths of the Saharan dust layer derived from two independent methods were compared with those obtained from the Meteosat data. Although the LITE-derived optical depth patterns from the two methods are in good agreement with each other, they show some differences with those derived from the satellite data, particularly in the inference of heavy dust concentration over the E. Atlantic. C1 NASA, Goddard Space Flight Ctr, Sci Syst Applicat Inc, Greenbelt, MD 20771 USA. RP Karyampudi, VM (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst Applicat Inc, Greenbelt, MD 20771 USA. OI Grant, William/0000-0002-1439-3285 NR 0 TC 1 Z9 1 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 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 208 EP 217 DI 10.1117/12.319562 PG 10 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900028 ER PT S AU Barnes, NP Walsh, BM AF Barnes, NP Walsh, BM BE Singh, UN Hu, H Wang, G TI Remote sensing of H2O at 0.94 mu m SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc DE H2O remote sensing; 0.946 mu m Nd : YAG; compositional tuning AB A H2O vapor remote sensing instrument which could operate in the 0.94 mu m region would have several highly desirable characteristics. Among the characteristics are access to absorption lines with approximately the correct strength and the availability of good detection systems. A good candidate for the laser for such a system is a Nd:garnet laser operating on one of the (4)F(3/)2 to I-4(9/2) transitions. TO make such a system a reality, NASA Langley has investigated compositional tuning to develop a laser at precisely the correct wavelength and methods of improving the efficiency. Both efforts have achieved success. A flashlamp pumped Nd:YAG laser operating at room temperature on the 0.946 mu m transition has achieved a threshold of 12 J and a slope efficiency of 0.009. 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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 283 EP 287 DI 10.1117/12.319567 PG 5 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900037 ER PT S AU Browell, EV AF Browell, EV BE Singh, UN Hu, H Wang, G TI Airborne differential absorption lidar and its evolution to space SO OPTICAL REMOTE SENSING FOR INDUSTRY AND ENVIRONMENTAL MONITORING SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Optical Remote Sensing for Industry and Environmental Monitoring CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci,Inst Atmospher Phys, CSSR, Chinese Soc Space Res, COEMA, China Opt & Optoelectron Mfg Assoc AB Airborne laser systems have been used for making remote measurements of ozone, water vapor, and aerosols in studies of many important atmospheric processes. Recent ozone and aerosol investigations have been conducted in the troposphere over western Pacific and in the stratosphere in the tropics and Arctic, and water vapor, aerosols, and cloud investigations have been conducted over land and water during daytime and nighttime conditions. Studies are also being conducted of future spaceborne laser systems for global investigations of ozone, water vapor, aerosols, and clouds. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Browell, EV (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 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 0-8194-2963-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3504 BP 584 EP 586 DI 10.1117/12.319575 PG 3 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL83K UT WOS:000076865900083 ER PT S AU Chu, WP Veiga, R AF Chu, WP Veiga, R BE Wang, J Wu, B Ogawa, T Guan, ZH TI SAGE III EOS SO OPTICAL REMOTE SENSING OF THE ATMOSPHERE AND CLOUDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Remote Sensing of the Atmosphere and Clouds CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Int Soc Opt Engn, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci, Inst Atmospher Phys, CSSR Chinese Soc Space Res, COEMA China Opt & Optoelectron Mfg Assoc DE remote sensing; space-borne instrument; aerosols; ozone; environmental monitoring; climate monitoring AB This paper describes the SAGE III (Stratospheric Aerosol and Gas Experiment III) experiments as part of the EOS program for long term monitoring of the atmospheric ozone and aerosol for global change study. SAGE III carries the heritage from the previous sensors SAM II, SAGE I, and SAGE II, which have provided stratospheric and tropospheric measurements of key atmospheric species such as aerosol, ozone, nitrogen dioxide, and water vapor. In addition to those atmospheric species, SAGE III will measure profiles of temperature, pressure, chlorine dioxide, and nitrogen trioxide using the solar and lunar occultation techniques. Three SAGE III instruments will be launched between 1999 and 2002. The First SAGE III will be on a Russian Meteor 3M spacecraft to be launched in 1999. The second SAGE III will be on the Space Station in 2002. The third SAGE III instrument is for a Flight of Opportunity, most probably will be flying in an inclined orbit for global coverage in 2001. The mission's science objectives, in terms of providing global measurements of key species for climate change study, and the algorithms used to retrieve the geophysical information from the measurements will be discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Chu, WP (reprint author), NASA, Langley Res Ctr, MS 475, Hampton, VA 23681 USA. NR 0 TC 3 Z9 3 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 0-8194-2960-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3501 BP 52 EP 60 DI 10.1117/12.577943 PG 5 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BL84H UT WOS:000076911000007 ER PT S AU Prabhakara, C Iacovazzi, R Yoo, JM Dalu, G AF Prabhakara, C Iacovazzi, R Yoo, JM Dalu, G BE Wang, J Wu, B Ogawa, T Guan, ZH TI Global warming estimation from MSU SO OPTICAL REMOTE SENSING OF THE ATMOSPHERE AND CLOUDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Remote Sensing of the Atmosphere and Clouds CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Int Soc Opt Engn, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci, Inst Atmospher Phys, CSSR Chinese Soc Space Res, COEMA China Opt & Optoelectron Mfg Assoc DE global warming; microwave remote sensing; calibration errors; diurnal cycle AB In this study, we develop an independent method to derive global temperature trend from Microwave Sounding Unit (MSU) radiometer observations in Ch 2 (53.74 GHz), made from sequential, sun-synchronous, polar-orbiting NOAA operational satellites. Also, a detailed examination of the systematic errors in these data is performed with the objective to improve this method. Partitioning these data from 75 N to 75 S into global land and ocean sets, and further subdividing them into am and pm subsets with the help of the LECT, enables us to perform this examination. The systematic errors in the MSU Ch 2 data are mainly related to differences in the MSU instrument calibration and the Local Equatorial Crossing Times (LECT) of successive satellites. They can be removed from these data with the help of the overlapping observations made by successive satellites. Errors in the MSU Ch 2 data are also introduced by orbital drift, which is the progressive change in the LECT of a satellite. Changes of the AM and PM observation times due to orbital drift causes Ch 2 brightness temperatures from each satellite to be affected by the diurnal cycle. In addition, orbital drift alters satellite illumination by sure, and thereby the instrument calibration. These errors introduced by orbital drift cannot be eliminated objectively. However, in this study, the uncertainty in the global temperature trend resulting from the cumulative error generated by drifts of all the satellites is inferred with an indirect approach. Based on our method of analysis of the MSU Ch 2 data, we find a global temperature trend from 1980 to 1996 of 0.11 K decade(-1) with an uncertainty of 0.06 K decade(-1). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Prabhakara, C (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2960-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3501 BP 284 EP 290 DI 10.1117/12.317772 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BL84H UT WOS:000076911000033 ER PT S AU Mauldin, L Salikhov, R Habib, S Vladimirov, A Carraway, D Petrenko, G Comella, J AF Mauldin, L Salikhov, R Habib, S Vladimirov, A Carraway, D Petrenko, G Comella, J BE Wang, J Wu, B Ogawa, T Guan, ZH TI Meteor-3M(1) Stratospheric Aerosol and Gas Experiment III (SAGE III) jointly sponsored by the National Aeronautics and Space Administration and the Russian Space Agency SO OPTICAL REMOTE SENSING OF THE ATMOSPHERE AND CLOUDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Remote Sensing of the Atmosphere and Clouds CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Int Soc Opt Engn, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci, Inst Atmospher Phys, CSSR Chinese Soc Space Res, COEMA China Opt & Optoelectron Mfg Assoc DE SAGE III; Meteor-3M; solar occultation; lunar occultation; spectrometer; aerosols; ozone; atmospheric science AB The Stratospheric Aerosol and Gas Experiment III (SAGE III) is a joint Earth Observing System (EOS) mission between the U.S. National Aeronautics and Space Administration (NASA) and the Russian Space Agency (RSA) to fly aboard the Russian Meteor-3M(1) spacecraft to be launched from the Baikonur Cosmodrome in mid-1999. SAGE III is a spectrometer that measures attenuated radiation in the 282 nm to 1550 nm wavelength range which can be inverted to yield vertical profiles of ozone, aerosols and other species that are critical in studying trends and global change. In addition to SAGE III, the Meteor-3M(1) spacecraft carries nine Russian instruments for analyzing and forecasting environmental change and climate, for hydro-meteorological monitoring and for helio-geophysical research. Both the RSA and NASA are coordinating the activities associated with the joint mission development and implementation, including instrument development, spacecraft development, and mission operations. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Mauldin, L (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 9 Z9 9 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 0-8194-2960-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3501 BP 355 EP 365 DI 10.1117/12.317767 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BL84H UT WOS:000076911000042 ER PT S AU Zong, J AF Zong, J BE Wang, J Wu, B Ogawa, T Guan, ZH TI Geometric retrieval of cloud top height from MISR imagery SO OPTICAL REMOTE SENSING OF THE ATMOSPHERE AND CLOUDS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Remote Sensing of the Atmosphere and Clouds CY SEP 15-17, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, Int Soc Opt Engn, Natl Ctr Atmospher Res, Atmospher Chem Div (USA), Chinese Acad Sci, Inst Atmospher Phys, CSSR Chinese Soc Space Res, COEMA China Opt & Optoelectron Mfg Assoc DE image registration; epipolar geometry; image matching; cloud motion; cloud height AB The Multi-angle Imaging SpectroRadiometor (MISR) instrument, a part of NASA's the Earth Observing System (EOS), is to be launched in 1999 aboard the EOS AM-1 satellite. The MISR instrument consists of nine pushbroom cameras pointing at discrete view angles. Multi-angle imagery from MISR creates opportunities to retrieve new scientific parameters relating to the earth's aerosols, clouds, and surface. This paper focuses on the accurate geometric retrieval of cloud top height from MISR data. It consists of three major processing steps. The first process projects and registers multi-angle MISR radiance imagery to an ellipsoidal earth surface represented by the WGS-84 ellipsoid. The result of this processing provides not only surface registration but also near epipolar imaging geometry. The next processing step separates the cloud motion and cloud height. Traditionally, this has been considered a singular problem in photogrammetry even with stereo imagery. However, a separation condition does exist with satellite imaging and multiple MISR camera look-angles. The last processing step automatically retrieves cloud-top height field in high resolution from ellipsoid-projected MISR radiance imagery. This paper presents the above three processing steps starting from an accurate and efficient projection of multi-angle MISR image data to the ellipsoid surface, followed by a mathematical derivation which separates the cloud motion and height, and finally an automatic image matching and ray intersection algorithm for high resolution cloud top height retrieval. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zong, J (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-315,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 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 0-8194-2960-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3501 BP 531 EP 541 PG 3 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BL84H UT WOS:000076911000062 ER PT S AU Scialdone, JJ AF Scialdone, JJ BE Chen, PT McClintock, WE Rottman, GJ TI Spacecraft compartment venting SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE spacecraft launch; compartment venting; contamination control AB At various times, concerns have been expressed that rapid decompressions of compartments of gas pockets and thermal blankets during spacecraft launches may have caused pressure differentials across their walls sufficient to cause minor structural failures, separations of adhesively-joined parts, ballooning, and flapping of blankets. This paper presents a close form equation expressing the expected pressure differentials across the walls of a compartment as a function of the external to the volume pressure drops, the pressure at which the rates occur and the vent capability of the compartment. The pressure profiles measured inside the shrouds of several spacecraft propelled by several vehicles and some profiles obtained from ground vacuum systems have been included. The equation can be used to design the appropriate vent, which will preclude excessive pressure differentials. Precautions and needed approaches for the evaluations of the expected pressures have been indicated. Methods to make a rapid assessment of the response of the compartment to rapid external pressure drops have been discussed. These are based on the evaluation of the compartment vent flow conductance, the volume and the length of time during which the rapid pressure drop occurs. C1 NASA, Goddard Space Flight Ctr, Mat Engn Branch, Greenbelt, MD 20771 USA. RP Scialdone, JJ (reprint author), NASA, Goddard Space Flight Ctr, Mat Engn Branch, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 23 EP 27 DI 10.1117/12.328500 PG 5 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100003 ER PT S AU Wooldridge, EM AF Wooldridge, EM BE Chen, PT McClintock, WE Rottman, GJ TI Contamination control considerations for the Next Generation Space Telescope (NGST) SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE contamination; infra-red optics; Next Generation Space Telescope; space deployable mirror; inflatable AB The NASA Space Science Program, in its ongoing mission to study the universe, has begun planning for a telescope that will carry on the Hubble Space Telescope's exploration. This telescope, the "Next Generation Space Telescope" (NGST), will be 6-8 meters in diameter, will be radiatively cooled to 30-60 Kelvin in order to enable extremely deep exposures at near infra-red wavelengths, and will operate for a lifetime of 5-10 years. The requirement will be to measure wavelengths from 1-5 microns, with a goal to measure wavelengths from 0.6-30 microns. As such, NGST will present a new contamination control challenge. The Goddard Space Flight Center (GSFC) performed one of three preliminary feasibility studies for the NGST, presenting a telescope with an 8 meter, deployable primary mirror and a deployable secondary mirror. The telescope would be radiatively cooled, with the optical telescope assembly (OTA) and the science instrument module (SIM) isolated from the wanner spacecraft support module (SSM). The OTA and the SIM would also be shielded from sunlight with an enormous, inflatable sunshield. The GSFC telescope was designed for launch on an Atlas IIAS, which would require launching the telescope in a stowed configuration, with the SSM, antennae, sunshield, primary mirror "petals", and secondary mirror deployed once on-orbit. The launch configuration and deployment scenario of an exposed telescope measuring near infrared and cooled to 30-60K are the factors presenting contamination hazards to the NGST mission. Preliminary science requirements established are: <20% reflectance decrease on optical surfaces over the wavelength range, and <0.3% obscuration of optical surfaces. In order to meet these requirements, NGST must be built and launched with careful attention to contamination control. Initial contamination control design options include strict selecting of materials and baking out of hardware down to the component level, minimizing or eliminating exposure of the OTA to sunlight or earth albedo during deployment and early on-orbit operations, cleaning of the primary and secondary mirrors at the launch site, cleaning of the launch vehicle fairing, locating thrusters and vents on the warm side of the sunshield only, and the possibility of including a deployable cover if that is shown to be necessary. C1 NASA, Goddard Space Flight Ctr, Mech Syst Ctr, Greenbelt, MD 20771 USA. RP Wooldridge, EM (reprint author), NASA, Goddard Space Flight Ctr, Mech Syst Ctr, Code 545, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 4 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 65 EP 73 DI 10.1117/12.328521 PG 9 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100007 ER PT S AU Sharma, PK Romana, EA Glassford, APM Steakley, JM AF Sharma, PK Romana, EA Glassford, APM Steakley, JM BE Chen, PT McClintock, WE Rottman, GJ TI Infrared detection of near co-orbiting particles in the SIRTF field-of-view SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE particulates; field-of-view; imaging; degradation; infrared AB Space Infrared Telescope Facility (SIRTF) will carry three instruments to explore the sky in the infrared: IRAC (1 to 10 mu m), IRS (10 to 40 mu m), and MIPS (10 to 180 mu m). SIRTF detectors have unprecedented sensitivity in all wavelength ranges. The particles, if present in the field of view (FOV) of the telescope, can cause significant imaging problems of the celestial objects if the thermal emission from the particles exceeds the background emission reaching the detector. Far-field particles may be identified as false targets. The near-field particles can light up the entire detector screen so that no other image may be observed while the particle stays in the field-of-view. Particles may be generated due to telescope aperture cover ejection, due to micrometeoroids colliding with the solar panel, or through other miscellaneous means. If the particle did not have a significant initial velocity component when it first entered the field-of-view, the only force to drive it out of the field-of-view is solar pressure. The time taken by a particle to traverse the field-of-view on account of the solar pressure alone may be several minutes. It is of interest to know the size and frequency of particles which can enter the telescope field-of-view without causing a substantial loss in the science data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sharma, PK (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 104 EP 112 DI 10.1117/12.328482 PG 9 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100010 ER PT S AU Mogan, PA Mattson, CB Schwindt, CJ AF Mogan, PA Mattson, CB Schwindt, CJ BE Chen, PT McClintock, WE Rottman, GJ TI Development of an airborne hydrocarbon monitoring system based on FTIR technology SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn AB The capability to monitor airborne hydrocarbon compounds is essential in order to protect sensitive optical payloads from performance degradation caused by the deposition of surface films. Commonly used hydrocarbon monitoring instrumentation such as Flame Ionization Detectors yield no information about the source or identity of compounds they detect. The Fourier Transform Infrared Spectrometer (FTIR) with its inherent ability to discriminate a large number of compounds offers a tremendous advantage over other types of instrumentation. The Contamination Monitoring Laboratory at John F. Kennedy Space Center has developed an airborne hydrocarbon monitoring system based on FTIR technology to support the AXAF payload. This system consists of a portable cart suitable for use in Class 1 Division 2 environments. This paper describes the system in detail. C1 NASA, KSC, DL, ICD A, Kennedy Space Ctr, FL 32899 USA. RP Mogan, PA (reprint author), NASA, KSC, DL, ICD A, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 0 Z9 0 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 133 EP 137 DI 10.1117/12.328485 PG 5 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100013 ER PT S AU Mogan, PA Schwindt, CJ AF Mogan, PA Schwindt, CJ BE Chen, PT McClintock, WE Rottman, GJ TI Real-time particulate fallout contamination monitoring technology development at NASA Kennedy Space Center SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn AB Two separate real-time particulate fallout monitoring instruments have been developed by the Contamination Monitoring Laboratory at NASA John F. Kennedy Space Center. These instruments monitor particulate fallout contamination deposition rates in cleanrooms and allow certification of cleanliness levels as well as proactive protection of valuable flight hardware. The Quantitative Contamination Monitor has been developed into a fieldable prototype instrument. This instrument directly images particulate fallout contamination accumulating on a witness surface and calculates percent area coverage as well as reporting particle size distributions in user-definable bins. The Optical Fallout Monitor is based on light scattering by contamination as it deposits onto a witness surface. This instrument provides quick response and a real-time estimate of percent area coverage. The Quantitative Contamination Monitor is useful as a facility monitoring tool for verification of compliance with standards such as MIL-STD-1246. The Optical Fallout Monitor is intended to be a relatively inexpensive unit for providing a real-time estimate of particulate fallout activity in areas within a facility which are of concern. The idea in using the Optical Fallout Monitor is to use a relatively large number of them around these sensitive areas. This paper discusses the technologies used in each of these instruments as well as their applications. Some test data will be presented and the results of a recent redesign of the Optical Fallout Monitor will be discussed. C1 NASA, DL, ICD A, Kennedy Space Ctr, FL 32899 USA. RP Mogan, PA (reprint author), NASA, DL, ICD A, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 0 Z9 0 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 138 EP 145 DI 10.1117/12.328486 PG 8 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100014 ER PT S AU Borson, EN Schwindt, CJ AF Borson, EN Schwindt, CJ BE Chen, PT McClintock, WE Rottman, GJ TI Measuring particle deposition on witness surfaces using a silicon wafer scanner SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE particle deposition; measurement; particle counting; area coverage; laser scanner; space systems; MIL-STD-1246 AB Monitoring of cleanroom and spacecraft cleanliness during ground processing operations is essential in order to verify performance requirements for optical systems prior to launch. The objective is to replace manual particle counting with automated panicle counting in order to reduce the processing time for the witness places and to improve precision and accuracy of the measurements. A modified silicon wafer inspection instrument, using a HeNe Laser light source, was used to count and size particles deposited on wafers exposed in the cleanrooms. The previous paper discussed measuring particles on silicon wafer witness plates during operations cleanrooms and discussed analytical methods For calculating percent area coverage (PAC). This paper describes the optical performance of the ESTEK instrument and tests on the instrument. C1 NASA, Goddard Space Flight Ctr, Swales Aerosp, Greenbelt, MD 20771 USA. RP Borson, EN (reprint author), NASA, Goddard Space Flight Ctr, Swales Aerosp, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 146 EP 153 DI 10.1117/12.328487 PG 8 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100015 ER PT S AU Benner, SM Lorentson, CC Chen, PT Thomson, SR AF Benner, SM Lorentson, CC Chen, PT Thomson, SR BE Chen, PT McClintock, WE Rottman, GJ TI Atomic oxygen erosion of a graphite coating on a TQCM aboard the Return Flux Experiment (REFLEX) SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE contamination; TQCM; REFLEX; atomic oxygen; erosion; graphite AB A TQCM coated with graphite was flown aboard a Spartan carrier in January 1996. During a flight of about 46 hours atom altitude of 305 km, the graphite reacted with the atomic oxygen (AO) in the environment and was eroded away. The 15-MHz TQCM's frequency dropped from 6800 to 4000 Hz in about 15 hours of exposure and was shown to be a strong function of the TQCM's orientation to the ram direction. The erosion rates for four different ram angles (18 degrees, 20 degrees, 61 degrees, and -62 degrees) was measured and found to be both consistent and repeatable. The average graphite volume loss for the 61 degrees and -62 degrees ram angles was calculated to be about 2xE-08 cm(3)/hr and for the 18 degrees and 19 degrees angles to be about 8.5xE-08 cm(3)/hr, which is slightly less than previous flight data. The erosion data was then correlated with AO density numbers for the particular times and positions of the spacecraft in orbit. From this analysis, an equation was derived that showed the carbon volume loss as a function of both atomic oxygen density and ram angle. For example, 1.59E-07 cm(3)/hr would be the calculated carbon volume loss fora ram angle of 0 degrees and an AO fluence of 3.52E+17 atoms/hr. The results of this data and analysis may lead to the development of a sensor capable of monitoring the AO fluence on a spacecraft. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Benner, SM (reprint author), NASA, Goddard Space Flight Ctr, Code 545, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 168 EP 177 DI 10.1117/12.328489 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100017 ER PT S AU Zwiener, JM Kamenetzky, RR Vaughn, JA Finckenor, MM AF Zwiener, JM Kamenetzky, RR Vaughn, JA Finckenor, MM BE Chen, PT McClintock, WE Rottman, GJ TI Contamination observed on the Passive Optical Sample assembly (POSA)-I experiment SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE space environment; contamination; spacecraft materials; Mir; space station; atomic oxygen; ultraviolet radiation; thermal control AB The passive Optical Sample Assembly-I (POSA-I), part of the Mir Environmental Effects payload (MEEP), was designed to study the combined effects of contamination, atomic oxygen, ultraviolet radiation, vacuum, thermal cycling, and other constituents of the space environment on spacecraft materials. The MEEP program is a Phase 1 International Space Station Risk Mitigation Experiment. The payload was attached by EVA to the exterior of the Mir docking module during the Space Shuttle mission STS-76. It was removed during STS-86 after exposure to the Mir space environment for 18 months. POSA-I consists of nearly 400 samples of thermal control paints, chemical conversion coatings, mirrors, optics, and baseline materials for International Space Station(ISS). POSA-I also flew state-of-the-art materials and passive instruments for monitoring the atomic oxygen and ultraviolet radiation dose to the experiment. Pre- and post-flight characterization of candidate spacecraft materials is discussed. Contamination was detected on the POSA-I experiment. On the side facing space (-Z(B) direction using the Mir coordinate system), visible contamination was observed. The contamination was uniform as would occur from a slow photodeposition process. A very definite film was deposited on the optical samples. The deposition appears to have directionality with definite shadowing effects. On the side facing the main Mir core (+Z(B) direction using the Mir coordinate system), no visible contamination was noted. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Zwiener, JM (reprint author), NASA, George C Marshall Space Flight Ctr, M-S EH12, Huntsville, AL 35812 USA. NR 0 TC 3 Z9 3 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 186 EP 195 DI 10.1117/12.328492 PG 10 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100019 ER PT S AU Markham, BL Seiferth, JC Smid, J Barker, JL AF Markham, BL Seiferth, JC Smid, J Barker, JL BE Chen, PT McClintock, WE Rottman, GJ TI Lifetime responsivity behavior of the Landsat-5 Thematic Mapper SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE Landsat-5; Thematic Mapper; responsivity; internal calibrator AB The responsivities of the Landsat-5 Thematic Mapper (TM) reflective bands are characterized over the lifetime of the instrument using its internal calibration system. This system illuminates only the focal planes and ail optics of the TM so that it does not capture changes in the telescope. The observed changes are quantified and categorized as to whether they are likely to be true instrument responsivity changes or changes in the internal calibrator system itself. Changes observed that are likely to be true instrument changes are: (1) 7%, 5%, 8% and 7% exponential-like decreases in responsivity with decay half lives of 250, 180, 60 and 110 days in bands 1 to 4, respectively, during the initial on-orbit period and (2) an oscillation in response of about 5% peak-to-peak in bands 5 and 7. The first effect is believed to originate in the TM spectral bandpass filters and the second effect is believed to be due to an icing build up in the cold focal plane window. Two rapid apparent responsivity changes, one a decrease and one an increase, which are peculiar to particular internal calibrator lamps are believed to. be due to changes in the lamp assemblies themselves as is a gradual increase in all (with the exception of band I) detectors' responsivities with time. An annual oscillation of up to 2% peak-to-peak in all bands is likely the product of both a temperature sensitivity of the IC and the TM primary focal plane. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Markham, BL (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 0 TC 15 Z9 15 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 420 EP 431 DI 10.1117/12.328513 PG 12 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100039 ER PT S AU Rawls, JR Mauldin, LE Chu, WP Maag, CR AF Rawls, JR Mauldin, LE Chu, WP Maag, CR BE Chen, PT McClintock, WE Rottman, GJ TI Effect of the induced contamination environment on the long-term degradation of optical payloads SO OPTICAL SYSTEMS CONTAMINATION AND DEGRADATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Optical Systems Contamination and Degradation CY JUL 20-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE contamination; contamination control; degradation; optical systems AB Degradation of sensitive satellite surfaces can adversely effect the accuracy, lifetime and mission effectiveness of a spacecraft or payload. More sophisticated and complex space systems have increased the concern about contamination. Thus, it has become necessary to develop better prediction tools and testing techniques for use in contamination prevention and control. This paper discusses the effect of the induced contamination environment on the long-term degradation of two (2) remote sensing instruments. Both instruments were the subject of contamination control programs. The Stratospheric Aerosol Gas Experiment (SAGE) II was launched by the shuttle on the Earth Resources Budget Satellite in 1984. The results of a throughput degradation contamination assessment performed prior to launch compares actual results acquired through March, 1998. The SAGE II instrument still continues to produce data within the limits predicted. A Total Ozone Mapping Spectrometer (TOMS:) was launched in 1991 on a Russian METEOR-3 spacecraft. Degradation of the solar calibration diffuser plates have been observed and reported earlier. A new instrument, SAGE III, will be launched in 1999 on another METEOR-3 spacecraft from the Baikonur Cosmodrome in Kazakhstan. The METEOR-3M/SAGE III is currently undergoing an intense contamination control program in order that data of the same quality as the SAGE II instrument will be realized. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Rawls, JR (reprint author), NASA, Langley Res Ctr, 10 Nasa Rd, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 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 0-8194-2882-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3427 BP 469 EP 476 DI 10.1117/12.328518 PG 8 WC Engineering, Aerospace; Optics SC Engineering; Optics GA BM07P UT WOS:000077549100043 ER PT J AU Abshire, JB Afzal, RS Smith, JC Sun, XL AF Abshire, JB Afzal, RS Smith, JC Sun, XL TI Mars orbiter laser altimeter measurements of the Mars surface SO OPTICS & PHOTONICS NEWS LA English DT Proceedings Paper CT Optical Amplifiers and Their Applications Topical Meeting CY JUL 21-23, 1997 CL VICTORIA, CANADA C1 NASA, Goddard Space Flight Ctr, Laser REmote Sensing Branch, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Elect & Comp Engn, Baltimore, MD 21218 USA. RP NASA, Goddard Space Flight Ctr, Laser REmote Sensing Branch, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1047-6938 EI 1541-3721 J9 OPT PHOTONICS NEWS JI Opt. Photonics News PD JAN PY 1998 VL 9 IS 1 BP 47 EP 47 PG 1 GA YV592 UT WOS:000071841900021 ER PT J AU Fariza, E Medina, A Deslis, A Estrela, JM AF Fariza, E Medina, A Deslis, A Estrela, JM TI Ultracompact telescopes SO OPTIK LA English DT Article AB A new telescope design is proposed in which two mirrors, embossed in a compact lens, are used to reflect light once or multiple times off each mirror. The optical path is folded with each reflection, and long focal length mirror-systems are achieved with an extremely short physical length. Applications of a multi-reflecting compact mirror system extend beyond the visible spectrum into the microwave region. C1 Univ Hosp, Valencia, Spain. Delta Opt, Pasadena, CA USA. CALTECH, NASA, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Valencia, Dept Physiol, Valencia, Spain. RP Fariza, E (reprint author), C-Falco 7,12, Castellon 12001, Spain. RI Estrela, Jose/H-4449-2015 OI Estrela, Jose/0000-0002-2540-9190 NR 7 TC 0 Z9 0 U1 0 U2 1 PU GUSTAV FISCHER VERLAG PI JENA PA VILLENGANG 2, D-07745 JENA, GERMANY SN 0030-4026 J9 OPTIK JI Optik PY 1998 VL 108 IS 1 BP 1 EP 3 PG 3 WC Optics SC Optics GA ZG730 UT WOS:000073033600001 ER PT B AU Bicay, MD Werner, MW AF Bicay, MD Werner, MW BE Woodward, CE Shull, JM Thronson, HA TI SIRTF: Linking the Great Observatories with the Origins Program SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off C1 CALTECH, Jet Prop Lab, SIRTF Project Off, Pasadena, CA 91109 USA. RP Bicay, MD (reprint author), CALTECH, Jet Prop Lab, SIRTF Project Off, 4800 Oak Grove Dr,MS 126-304, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 290 EP 297 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500015 ER PT B AU Lissauer, JJ AF Lissauer, JJ BE Woodward, CE Shull, JM Thronson, HA TI The birth of planetary systems SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. Another potential hazard to planetary systems is radial decay of planetary orbits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 327 EP 337 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500019 ER PT B AU Ward, WR AF Ward, WR BE Woodward, CE Shull, JM Thronson, HA TI On planet formation & migration SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB Some consequences of protoplanet migration for the planetary formation process are discussed. Migration of planet-sized objects can be caused by disk tidal torques. Two types of a migration are identified: a fast orbit decay relative to the disk (type I) at a rate proportional to the planet's mass, and a slow co-evolution with the disk (type II) at a rate set by the disk's viscosity. Smaller (larger) protoplanets execute the former (latter), and a transition I --> II occurs at a critical mass (Shiva limit). The fast mode is a precarious stage in the planet's development, in which orbital decay threatens to drive the embryo into the star. Comparison of growth and orbital decay times defines an upper mass limit for survival. Although it is possible that both the terrestrial and outer most planets of our solar system remained below this limit throughout the disk's lifetime, this possibility is not open to Jupiter and Saturn. Their existence is somewhat of a conundrum, and several possible mechanisms that could have contributed to their survival are considered. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ward, WR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 338 EP 346 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500020 ER PT B AU Zahnle, K AF Zahnle, K BE Woodward, CE Shull, JM Thronson, HA TI Origins of atmospheres SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB Atmospheres are found enveloping those planets and satellites best able to hold them. Apparently, the existence of an atmosphere depends as much on escape as it does on supply. A consequence of this view is that volatile supplies were probably much greater than the atmospheres that remain. The likeliest candidates are sources associated with the major events of planetary accretion itself, such as volatile-rich planetesimals or direct gravitational capture of nebular gases. Late-accreting volatile-rich veneers, either asteroids or comets, seem attractive but present quantitative difficulties. Comets in particular appear to be quantitatively inadequate. Only one comet in three million hits Earth. For Earth to accrete an ocean of water through comets, some 3000M(circle plus) of comets must have been scattered to the Oort Cloud or beyond. This is excessive. This difficulty applies to Uranus-Neptune planetesimals as well as to a putative massive early Kuiper Belt. Objects falling from a much augmented ancient asteroid belt remain a viable option, but timing is an issue: can the depopulation of a massive asteroid belt be delayed long enough that it makes sense to talk of asteroids as a late veneer? Another appealing candidate population of volatile-rich objects for the inner Solar System are scattered planetesimals associated with the accretion of Jupiter, for two reasons: (i) before there was Jupiter, there was no object in the Solar System capable of expelling comets efficiently; (ii) the cross-section of the inner Solar System to stray objects was greater when there were many planetesimals. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Zahnle, K (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 0 TC 13 Z9 12 U1 0 U2 3 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 364 EP 391 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500022 ER PT B AU Sandford, SA Allamandola, LJ Bernstein, MP AF Sandford, SA Allamandola, LJ Bernstein, MP BE Woodward, CE Shull, JM Thronson, HA TI Organic chemistry: From the interstellar medium to the Solar System SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB A wide variety of organic compounds are observed in different environments in the interstellar medium. The processes by which these materials may have formed and been modified are reviewed, and evidence is presented that demonstrates that a measurable fraction of this material survived incorporation, substantially unaltered, into our Solar System during its formation. The nature of this material is of direct interest to issues associated with the origin of life, both because it represents a large fraction of the Solar System inventory of the biogenically-important elements, and because many of the compounds in this inventory have biogenic implications. Several specific examples of such molecules are briefly discussed. C1 NASA, Ames Res Ctr, Astrophys Branch, Moffett Field, CA 94035 USA. RP Sandford, SA (reprint author), NASA, Ames Res Ctr, Astrophys Branch, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 392 EP 414 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500023 ER PT B AU Des Marais, DJ AF Des Marais, DJ BE Woodward, CE Shull, JM Thronson, HA TI Earth's early biosphere and its environment SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB Understanding our own early biosphere is essential to our search for life elsewhere, because life arose on Earth very early and rocky planets shared similar early histories. The environment between 3.8 and 3.0 billion years (Ga) ago was as warm or warmer than today, sustained abundant hydrothermal activity and aggressive chemical weathering and had an atmosphere rich in CO2 and low in O-2. The early biosphere arose before 3.8 Ga ago, was exclusively unicellular and was dominated by hyperthermophiles that utilized chemical sources of energy and employed a range of metabolic pathways for CO2 assimilation. Photosynthesis arose later but still prior to 3.0 Ga. The transition toward the modern global environment was paced by a decline in volcanic and hydrothermal activity, coupled to a coalescence, stabilization and emergence of the continents. These developments created new environmental niches for life and allowed atmospheric CO2 levels to decline and O-2 levels to increase. The O-2 increase created new niches for aerobic life, most notably the more advanced Eukarya that eventually spawned the megascopic fauna and flora of our modern biosphere. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Des Marais, DJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 0 TC 2 Z9 3 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 415 EP 434 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500024 ER PT B AU McKay, CP AF McKay, CP BE Woodward, CE Shull, JM Thronson, HA TI Life in the planetary context SO ORIGINS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT International Conference on Origins CY MAY 19-23, 1997 CL ESTES PK, CO SP Univ Colorado, Univ Wyoming, NASA, Origins Program Off AB The search for life on other worlds is a key goal for space science. The basis for such a search must be an understanding of life on Earth. Of particular interest is the ecological limits of life. In the broadest sense, the requirements for life are: 1) energy (usually sunlight but chemical energy may also be used), 2) carbon, 3) liquid water, 4) some other elements such as N, P, S. Of these requirements liquid water is the limiting factor for life on other worlds. On Earth life appears early in the geological record suggesting that life can emerge rapidly - on geological timescales - under suitable conditions. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP McKay, CP (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-68-6 J9 ASTR SOC P PY 1998 VL 148 BP 449 EP 455 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75H UT WOS:000076574500026 ER PT B AU Fijany, A Cagin, T Jaramillo-Botero, A Goddard, W AF Fijany, A Cagin, T Jaramillo-Botero, A Goddard, W BE DHollander, EH Peters, FJ Joubert, GR Trottenberg, U TI A fast algorithm for massively parallel, long-term, simulation of complex molecular dynamics systems SO PARALLEL COMPUTING: FUNDAMENTALS, APPLICATIONS AND NEW DIRECTIONS SE ADVANCES IN PARALLEL COMPUTING LA English DT Proceedings Paper CT Parallel Computing Conference (ParCo97) CY SEP 19-22, 1997 CL BONN, GERMANY SP Ascend Commun GmbH, debis Systemhaus GmbH, Deutsch Telekom, DIGITAL Equipment GmbH, Elsevier Sci BV, ERCIM, GMD-German Natl Res Ctr Informat Technol, Hewlett Packard Corp, Hitachi Europe Ltd, HPCnet, IBM Deutschland Informationssystem GmbH, NEC C&C Res Labs, o tel o Kommunikat GmbH, Pallas GmbH, Parsytec Comp GmbH, Siemens-Nixdorf Informationssysteme AG, Silicon Graphics/CRAY Res GmbH, SUN Microsyst, Visual Numerics ID CELL MULTIPOLE METHOD; MASS OPERATOR METHOD; NONBOND INTERACTIONS; COMPUTATION; PROGRAM; COULOMB AB In this paper a new algorithm for solution of constrained equations of motion (EOM) with application to simulation of molecular dynamics systems is presented. The algorithm enables the solution of EOR;I with an internal coordinates model wherein the high frequency oscillations are frozen by explicit inclusion of hard constraints in the system as well as by clustering of atoms and thus it allows a much larger time step in the integration. For a molecular system with N clusters, the algorithm achieves the optimal sequential complexity of O(N). However, the main advantage of this new algorithm is its efficiency for massively parallel computation. In fact, this is the first known algorithm that achieves a both time- and processor-optimal parallel solution of constrained EOM, i.e., a computation time of O(Log N) by using O(N) processors. In addition to its theoretical significance this algorithm Is also very efficient for practical implementation on parallel architectures due to its highly decoupled computational structure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Fijany, A (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 23 TC 2 Z9 2 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS BN 0-444-82882-6 J9 ADV PAR COM PY 1998 VL 12 BP 505 EP 515 PG 5 WC Computer Science, Theory & Methods SC Computer Science GA BM46D UT WOS:000078812100062 ER PT S AU Yan, JC Schmidt, MA AF Yan, JC Schmidt, MA BE DHollander, EH Peters, FJ Joubert, GR Trottenberg, U TI Constructing space-time views from fixed size trace files - Getting the best of both worlds SO PARALLEL COMPUTING: FUNDAMENTALS, APPLICATIONS AND NEW DIRECTIONS SE Advances in Parallel Computing LA English DT Proceedings Paper CT Parallel Computing Conference (ParCo97) CY SEP 19-22, 1997 CL BONN, GERMANY SP Ascend Commun GmbH, debis Systemhaus GmbH, Deutsch Telekom, DIGITAL Equipment GmbH, Elsevier Sci BV, ERCIM, GMD-German Natl Res Ctr Informat Technol, Hewlett Packard Corp, Hitachi Europe Ltd, HPCnet, IBM Deutschland Informationssystem GmbH, NEC C&C Res Labs, o tel o Kommunikat GmbH, Pallas GmbH, Parsytec Comp GmbH, Siemens-Nixdorf Informationssysteme AG, Silicon Graphics/CRAY Res GmbH, SUN Microsyst, Visual Numerics AB The performance data gathered and analyzed by monitoring tools currently available to the super-computing community falls under two categories: statistics and event traces. Statistical data is much more compact but lacks the probative power event traces offer. Evens traces. on the other hand, can be extremely large even for short executions of simple programs. In this paper, we propose an innovative methodology for performance data gathering and representation. The user br ill be able to limit the amount of trace data collected and at the same time, carry out some of the analysis event traces offer. Two basic ideas were employed: the use of averages to approximate different execution instances of the same program construct and "formulae" to represent repetitive sequences associated with communication and control flow (such as message passing and branching). With the help of a few Examples, we illustrate the use of these techniques and evaluated the quality of the performance data we collected. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Yan, JC (reprint author), NASA, Ames Res Ctr, MS T27A-1, Moffett Field, CA 94035 USA. EM yan@nas.nasa.gov; schmidt@nas.nasa.gov NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-5452 BN 0-444-82882-6 J9 ADV PARALLEL COMPUT PY 1998 VL 12 BP 633 EP 640 PG 4 WC Computer Science, Theory & Methods SC Computer Science GA BM46D UT WOS:000078812100078 ER PT S AU Fukunaga, AS AF Fukunaga, AS BE Eiben, AE Back, T Schoenauer, M Schwefel, HP TI Restart scheduling for genetic algorithms SO PARALLEL PROBLEM SOLVING FROM NATURE - PPSN V SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT 5th International Conference on Parallel Problem Solving from Nature (PPSN V) CY SEP 27-30, 1998 CL AMSTERDAM, NETHERLANDS SP European Network Excellence Evolutionary Computat, Informatik Centrum Dortmund, Inst Programming Technol & Algorithm, Int Soc Genet Algorithms, Leiden Ctr Nat Comp, Municipal Amsterdam, Philips Siemens AG, Stichting European Evolutionary Comp Conf AB In order to escape from local optima, it is standard practice to periodically restart heuristic optimization algorithms such as genetic algorithm according to some restart criteria/policy. This paper addresses the issue of finding a good restart strategy in the context of resource-bounded optimization scenarios, in which the goal is to generate the best possible solution given a fixed amount of time. We propose the use of a restart scheduling strategy which generates a static restart strategy with optimal expected utility, based on a database of past performance of the algorithm on a class of problem instances. We show that the performance of static restart schedules generated by the approach can be competitive to that of a commonly used dynamic restart strategy based on detection of lack of progress. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fukunaga, AS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 126-347, Pasadena, CA 91109 USA. NR 8 TC 17 Z9 17 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-65078-4 J9 LECT NOTES COMPUT SC PY 1998 VL 1498 BP 357 EP 366 PG 10 WC Computer Science, Theory & Methods SC Computer Science GA BN73W UT WOS:000082774900035 ER PT S AU Desai, MI Bothmer, V Marsden, RG Sanderson, TR Balogh, A Forsyth, RJ Goldstein, BE AF Desai, MI Bothmer, V Marsden, RG Sanderson, TR Balogh, A Forsyth, RJ Goldstein, BE BE Blake, JB Slavin, JA TI Acceleration in energetics ions (similar to 1 MeV) in corotating interaction regions SO PARTICLE ACCELERATION IN SPACE PLASMAS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 3 Symposium of COSPAR Scientific-Commission-D on Particle Acceleration in Space Plasmas at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL UNIV BIRMINGHAM, BIRMINGHAM, ENGLAND SP Comm Space Res, Sci Comm Solar Terr Phys, European Space Agcy HO UNIV BIRMINGHAM ID ULYSSES OBSERVATIONS; ECLIPTIC-PLANE; SOLAR; STREAM; SHOCKS AB We have correlated the similar to 1 MeV proton intensity (J) measured at corotating reverse shocks detected by Ulysses near the ecliptic plane and in the southern hemisphere with the shock strength and shock normal angle. We find that J is essentially independent of the shock strength below 29 degrees S, whereas between 29 degrees and 41 degrees S J showed a good correlation with the same. The poor correlation below 29 degrees S is attributed to temporal variations in the background intensity and to the presence of particles accelerated at other corotating and transient shocks. J is also independent of the shock normal angle at all latitudes, which is probably due to the combined effects of the drift and diffusive acceleration processes. We compensate for the effects of variations in the background by assuming that two reverse shocks observed during the same similar to 26 day period accelerate particles out of the same background population. By correlating the ratio of the proton intensities with the ratios of the shock parameters for such pairs of reverse shocks, we show that the shock acceleration efficiency is well correlated with the strength but is independent of the normal angle. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 ESA, Dept Space Sci, Noordwijk, Netherlands. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Desai, MI (reprint author), ESA, Dept Space Sci, Noordwijk, Netherlands. NR 13 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043312-X J9 ADV SPACE RES PY 1998 VL 21 IS 4 BP 555 EP 558 DI 10.1016/S0273-1177(97)00962-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Physics, Fluids & Plasmas SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Physics GA BL12R UT WOS:000074378900005 ER PT S AU Baker, DN Li, X Blake, JB Kanekal, S AF Baker, DN Li, X Blake, JB Kanekal, S BE Blake, JB Slavin, JA TI Strong electron acceleration in the Earth's magnetosphere SO PARTICLE ACCELERATION IN SPACE PLASMAS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT D0 3 Symposium of COSPAR Scientific-Commission-D on Particle Acceleration in Space Plasmas at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL UNIV BIRMINGHAM, BIRMINGHAM, ENGLAND SP Comm Space Res, Sci Comm Solar Terr Phys, European Space Agcy HO UNIV BIRMINGHAM ID RELATIVISTIC ELECTRONS; MIDDLE ATMOSPHERE AB Electron data are examined over long periods in the outer zone of electron trapping (L greater than or similar to 3). Energetic particle detectors at geostationary orbit and onboard the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite show evidence of strong electron acceleration in Earth's outer radiation belts. Data are studied according to L-value and are compared with concurrent solar.wind and geomagnetic conditions. Evidence is presented of a strong correlation between high-speed solar wind speeds and the occurrence of high energy electrons in the Earth's outer radiation belts. Thus, high-speed solar wind streams apparently drive the acceleration of electrons throughout the outer zone on time scales of days. The processes by which electrons are accelerated to high energies (E>1 MeV) are found to consist of two temporally distinct steps. The first involves prompt, relatively modest, acceleration of many electrons during magnetospheric substorms. The second step involves higher energy acceleration of a portion of the substorm electrons throughout the outer trapping region on a time scale of days. (C) 1998 COSAR. Published by Elsevier Science Ltd. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. Aerospace Corp, Los Angeles, CA 90009 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Baker, DN (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NR 12 TC 53 Z9 55 U1 0 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043312-X J9 ADV SPACE RES PY 1998 VL 21 IS 4 BP 609 EP 613 DI 10.1016/S0273-1177(97)00970-8 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Physics, Fluids & Plasmas SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Physics GA BL12R UT WOS:000074378900013 ER PT S AU O'Brien, JF Goullioud, R Neat, GW AF O'Brien, JF Goullioud, R Neat, GW BE Davis, LP TI Micro-precision interferometer: Evaluation of new disturbance isolation solutions SO PASSIVE DAMPING AND ISOLATION - SMART STRUCTURES AND MATERIALS 1998 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Smart Structures and Materials 1998 - Passive Damping and Isolation CY MAR 02-03, 1998 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers, Soc Exptl Mech Inc, Amer Soc Mech Engineers, BF Goodrich Aerosp, USAF Res Lab, Def Adv Res Projects Agcy, Ceram Soc Japan, Intelligent Mat Forum, Japan, USA Res Off DE interferometry; Micro-Precision Interferometer; vibration isolation; hexapod; vibration attenuation AB This paper describes a benchmark to assess performance of six-axis vibration isolation systems. The targeted application, spaceborne interferometers, require isolation of the reaction wheel disturbances in order to stabilize the precision optical elements to the required levels. The problem is to isolate this vibrating payload from the quiet structure (spacecraft). The unique feature of this procedure is that isolator performance is measured in terms of the stability of the interferometer optical elements. Central to the procedure is the Micro-Precision Interferometer (MPI) testbed which is a hardware model of a future spaceborne optical interferometer. The isolation system under evaluation is mounted on the testbed and disturbance transfer functions are then measured from the isolator payload to the optical sensor output that must be stabilized. Off-line, the procedure combines these measured testbed transfer functions with an empirical model of the reaction wheel disturbance, in order predict isolator performance over the entire range of wheel speeds. The paper applies the procedure to four different disturbance interface conditions: hard mounted, passive hexapod isolator, active hexapod isolator and a passive elastomeric isolator. The paper contains all the necessary information to allow industry, academia or other organizations to evaluate custom designs in this testbed facility. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. RP Neat, GW (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. NR 0 TC 6 Z9 6 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 0-8194-2771-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3327 BP 387 EP 398 DI 10.1117/12.310701 PG 12 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Materials Science, Multidisciplinary; Mechanics; Optics SC Acoustics; Engineering; Materials Science; Mechanics; Optics GA BL31L UT WOS:000075068000034 ER PT S AU Racette, PE Wang, JR AF Racette, PE Wang, JR BE Smith, RM TI Passive millimeter and sub-millimeter-wave imaging for atmospheric research SO PASSIVE MILLIMETER-WAVE IMAGING TECHNOLOGY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Passive Millimeter-Wave Imaging Technology II CY APR 13, 1998 CL ORLANDO, FL SP SPIE AB In recent years there has been considerable advancement in millimeter and submillimeter wave radiometry applied to atmospheric remote sensing. Contributing to this advancement are the measurements made by the Millimeter-wave Imaging Radiometer (MIR) and subsequent analysis of the data. The MIR is an imaging radiometer designed to fly aboard the National Aeronautics and Space Administration's (NASA) ER-2 high altitude aircraft with nine frequency channels between 89 and 325 GHz. Since its maiden flight in May 1992, the MIR has flown over 80 sorties comprising more than 300 flight hours. In addition, the instrument has participated in several ground-based experiments yielding hundreds of hours of data. The MIR data have been used for comparing atmospheric water vapor profiles derived from different measuring techniques. Images of the atmosphere reveal these frequencies are sensitive to the presence of liquid and ice clouds; analysis of the data suggests that characteristics of the clouds may be extracted from the data. The instrument has also been used to support calibration and validation studies of satellite sensors. Analysis indicates ground-based radiometric observations near the 183 GHz water vapor absorption line may be useful for obtaining accurate ground-based measurements of low values (< 1.0 cm) of precipital water vapor. This paper describes the application and utility of millimeter and sub-millimeter wave radiometric imaging for atmospheric research in the context of accomplishments attained with the MIR. C1 NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. RP Racette, PE (reprint author), NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Mail Code 975, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2827-2 J9 P SOC PHOTO-OPT INS PY 1998 VL 3378 BP 114 EP 122 DI 10.1117/12.319393 PG 9 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL67W UT WOS:000076298300014 ER PT J AU Teo, PC Hel-Or, Y AF Teo, PC Hel-Or, Y TI Lie generators for computing steerable functions SO PATTERN RECOGNITION LETTERS LA English DT Article DE steerable filters; filter design; low-level vision; feature detection; Lie groups ID DECOMPOSITION; FILTERS; PHASE AB We present a computational, group-theoretic approach to steerable functions. The approach is group-theoretic in that the treatment involves continuous transformation groups for which elementary Lie group theory may be applied. The approach is computational in that the theory is constructive and leads directly to a procedural implementation. For functions that are steerable with n basis functions under a k-parameter group, the procedure is efficient in that at most nk + 1 iterations of the procedure are needed to compute all the basis functions. Furthermore, the procedure is guaranteed to return the minimum number of basis functions. If the function is not steerable, a numerical implementation of the procedure could be used to compute basis functions that approximately steer the function over a range of transformation parameters. Examples of both applications are described. (C) 1998 Elsevier Science B.V. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Dept Comp Sci, Stanford, CA 94305 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 15 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8655 EI 1872-7344 J9 PATTERN RECOGN LETT JI Pattern Recognit. Lett. PD JAN PY 1998 VL 19 IS 1 BP 7 EP 17 DI 10.1016/S0167-8655(97)00156-6 PG 11 WC Computer Science, Artificial Intelligence SC Computer Science GA ZV858 UT WOS:000074348800002 ER PT J AU Beard, BL Ahumada, AJ AF Beard, B. L. Ahumada, A. J., Jr. TI Template learning model predicts effects of fixed versus random noise in visual signal detection SO PERCEPTION LA English DT Meeting Abstract C1 [Beard, B. L.; Ahumada, A. J., Jr.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM tlbeard@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 7 EP 7 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400018 ER PT J AU Watson, AB AF Watson, A. B. TI Estimating video quality with a vision model SO PERCEPTION LA English DT Meeting Abstract C1 [Watson, A. B.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM abwatson@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 40 EP 40 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400107 ER PT J AU Foster, DH Nascimento, SMC Arend, L Linnell, KJ Nieves, JL Plet, S AF Foster, D. H. Nascimento, S. M. C. Arend, L. Linnell, K. J. Nieves, J. L. Plet, S. TI Parallel processing of surface-reflectance change under illuminant change SO PERCEPTION LA English DT Meeting Abstract C1 [Foster, D. H.] Aston Univ, Birmingham B4 7ET, W Midlands, England. [Nascimento, S. M. C.] Univ Minho, Dept Phys, P-4709 Braga, Portugal. [Arend, L.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Linnell, K. J.] Univ Birmingham, Sch Psychol, Birmingham B15 2TT, W Midlands, England. [Nieves, J. L.] Univ Granada, Dept Opt, E-18071 Granada, Spain. [Plet, S.] Univ Trieste, Dept Psychol, I-34023 Trieste, Italy. EM d.h.foster@aston.ac.uk NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 43 EP 43 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400115 ER PT J AU Eckstein, MP Beutter, BR AF Eckstein, M. P. Beutter, B. R. TI Analytic implementation of the guided-search model allows comparisons with signal detection models in target-localisation accuracy tasks SO PERCEPTION LA English DT Meeting Abstract C1 [Beutter, B. R.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. [Eckstein, M. P.] Cedars Sinai Med Ctr, Dept Med Phys & Imaging, Los Angeles, CA 90048 USA. EM miguel@vision.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 62 EP 63 PG 2 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400165 ER PT J AU Ahumada, AJ Beard, BL AF Ahumada, A. J., Jr. Beard, B. L. TI Masking by compound gratings described by an image-sequence-discrimination model SO PERCEPTION LA English DT Meeting Abstract C1 [Ahumada, A. J., Jr.; Beard, B. L.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM al@vision.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 82 EP 83 PG 2 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400221 ER PT J AU Chukova, SV Ahumada, AJ AF Chukova, S. V. Ahumada, A. J., Jr. TI What determines the response: test or reference? SO PERCEPTION LA English DT Meeting Abstract C1 [Chukova, S. V.] IP Pavlov Physiol Inst, St Petersburg 199034, Russia. [Ahumada, A. J., Jr.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM al@vision.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 155 EP 155 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400419 ER PT J AU Mulligan, JB AF Mulligan, J. B. TI Ocular pursuit of flicker-defined motion SO PERCEPTION LA English DT Meeting Abstract C1 [Mulligan, J. B.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM jbm@vision.arc.nasa.gov NR 0 TC 1 Z9 1 U1 0 U2 0 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 SU S BP 183 EP 183 PG 1 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA V17AP UT WOS:000207910400495 ER PT J AU Post, RB Welch, RB Caufield, K AF Post, RB Welch, RB Caufield, K TI Relative spatial expansion and contraction within the Muller-Lyer and Judd illusions SO PERCEPTION LA English DT Article ID LINE BISECTION; DISSOCIATION; POSITION AB The shaft portions of Muller-Lyer (M-L) figures, one-ended M-L figures, Judd figures, and their respective control (tails-up) figures were divided by subjects into eight equal-appearing intervals by means of successive bisections. For most of the control stimuli the length of the left half of the shaft tended to be overestimated relative to the length of the right side. For the tails-out version of the M-L figure, there was relative overestimation of segments of the shaft adjacent to the tails, while for the tails-in version there was relative underestimation of these segments. These results indicate that the distortion of perceived length in the M-L illusion is not distributed evenly along the shaft. For the one-ended M-L figures the apparent overestimations and underestimations extended further along the shaft than for the standard figures. For the Judd figure perceived length varied systematically along the length of the shaft from underestimation near the rails-in end of the figure to overestimation near the tails-out end. These results are contradictory to the hypothesis that the M-L illusion results from inappropriate size scaling produced through the operation of size-constancy mechanisms, since this conjecture would predict uniform expansion or contraction. The results are compared with findings that localization responses are accurate for M-L figures but biased for one-ended M-L figures and Judd figures. C1 Univ Calif Davis, Dept Psychol, Davis, CA 95616 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Post, RB (reprint author), Univ Calif Davis, Dept Psychol, Davis, CA 95616 USA. NR 18 TC 16 Z9 17 U1 0 U2 3 PU PION LTD PI LONDON PA 207 BRONDESBURY PARK, LONDON NW2 5JN, ENGLAND SN 0301-0066 J9 PERCEPTION JI Perception PY 1998 VL 27 IS 7 BP 827 EP 838 DI 10.1068/p270827 PG 12 WC Ophthalmology; Psychology; Psychology, Experimental SC Ophthalmology; Psychology GA 140LP UT WOS:000077089000008 PM 10209645 ER PT S AU Krabach, TN Gunapala, SD Bandara, SV Liu, JK Pool, FS Sengupta, DK Shott, CA Carralejo, R AF Krabach, TN Gunapala, SD Bandara, SV Liu, JK Pool, FS Sengupta, DK Shott, CA Carralejo, R BE Brown, GJ TI Recent progress in Quantum Well Infrared Photodetector research and development at Jet Propulsion Laboratory SO PHOTODETECTORS: MATERIALS AND DEVICES III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photodetectors - Materials and Devices III CY JAN 28-30, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE quantum wells; infrared detectors; focal plane arrays; dualband detectors; broad-band detectors AB One of the simplest device realizations of the classic particle-in-the-box problem of basic quantum mechanics is the Quantum Well Infrared Photodetector (QWIP). In this paper we discuss the optimization of the detector design, material growth and processing that has culminated in realization of 15 micron cutoff 125 x 128 QWIP focal plane array camera, handheld and palmsize 256 x 256 long-wavelength QWIP cameras and 648 x 480 long-wavelength cameras, holding forth great promise for myriad applications in 6-25 micron wavelength range in science, medicine, defense and industry. In addition, we present the recent developments in broadband QWIPs and mid-wave long-wave dualband QWIPs at Jet Propulsion Laboratory for various NASA and DOD applications. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Krabach, TN (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 1 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 0-8194-2726-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3287 BP 128 EP 137 DI 10.1117/12.304504 PG 10 WC Instruments & Instrumentation; Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Optics SC Instruments & Instrumentation; Materials Science; Optics GA BK88U UT WOS:000073807600015 ER PT S AU Yao, XS Maleki, L Wu, C Davis, L Forouhar, S AF Yao, XS Maleki, L Wu, C Davis, L Forouhar, S BE Zagar, GJ Goutzoulis, AP Pirich, AR TI Recent results with coupled opto-electronic oscillator SO PHOTONICS AND RADIO FREQUENCY II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photonics and Radio Frequency II CY JUL 21-22, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE opto-electronic oscillator; optical pulse; RF photonics; signal generation; mode-locked lasers; microwave generation; phase noise; jitter AB We present experimental results of coupled opto-electronic oscillators (COEO) constructed with a semiconductor optical amplifier based ring laser, a semiconductor Fabry-Perot laser, and a semiconductor colliding pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices, we obtained optical pulses as short as 6 picoseconds and RF signals as high in frequency as 18 GHz with a spectral purity comparable with a HP8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yao, XS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 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 0-8194-2918-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3463 BP 237 EP 245 DI 10.1117/12.330392 PG 9 WC Optics; Telecommunications SC Optics; Telecommunications GA BM20Q UT WOS:000078028800026 ER PT S AU Pearson, SD Hardage, DM AF Pearson, SD Hardage, DM BE Taylor, EW TI NASA's space environments & effects (SEE) program: The pursuit of tomorrow's space technology SO PHOTONICS FOR SPACE ENVIRONMENTS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photonics for Space Environments VI CY JUL 22, 1998 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE space environments; ionizing radiation; technology development; environmental effects AB A hazard to all spacecraft orbiting the earth and exploring the unknown in deep space is the existence of a harsh and ever changing environment with its subsequent effects.(1,2) Some of these environmental hazards, such as plasma, extreme thermal excursions, meteoroids, and ionizing radiation result from natural sources, whereas others, such as orbital debris and neutral contamination are induced by the presence of spacecraft themselves. The subsequent effects can provide damaging or even disabling effects on spacecraft, its materials, and its instruments. in partnership with industry, academia, and other government agencies, National Aeronautics & Space Administration's (NASA's) Space Environments & Effects (SEE) Program defines the space environments and advocates technology development to accommodate or mitigate these harmful environments on the spacecraft. This program provides a very comprehensive and focused approach to understanding the space environment, to define the best techniques for both flight and ground-based experimentation, to update the models which predict both the environments and the environmental effects on spacecraft, and finally to ensure that this information is properly maintained and inserted into spacecraft design programs. This paper will provide an overview of the Program's purpose, goals, database management and technical activities. In particular, the SEE Program has been very active in developing improved ionizing radiation models and developing related flight experiments which should aid in determining the effect of the radiation environment on modern electronics. C1 NASA, George C Marshall Space Flight Ctr, Electromagnet & Aerosp Environments Branch, Syst Anal & Integrat Lab, Huntsville, AL 35812 USA. RP Pearson, SD (reprint author), NASA, George C Marshall Space Flight Ctr, Electromagnet & Aerosp Environments Branch, Syst Anal & Integrat Lab, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 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 0-8194-2895-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3440 BP 2 EP 13 DI 10.1117/12.326683 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BM19V UT WOS:000078010000001 ER PT S AU Ott, MN AF Ott, MN BE Taylor, EW TI Fiber optic cable assemblies for space flight II: thermal and radiation effects SO PHOTONICS FOR SPACE ENVIRONMENTS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photonics for Space Environments VI CY JUL 22, 1998 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE fiber optic; cable; radiation effects; thermal effects; shrinkage; jacketing; space flight; cable assemblies; multimode; preconditioning AB Goddard Space Flight Center is conducting a search for space flight worthy fiber optic cable assemblies that will benefit all projects at all of the NASA centers. This paper is number two in a series of papers being issued as a result of this task to define and qualify space grade fiber optic cable assemblies. Though to qualify and use a fiber optic cable in space requires treatment of the cable assembly as a system, it is very important to understand the design and behavior of its parts. This paper addresses that need, providing information on cable components shrinkage testing and radiation testing results from recent experiments at Goddard Space Flight Center. This work is an extension of the "lessons learned" reported in the first paper of this series entitled "Fiber Optic Cable Assemblies for Space Flight: Issues and Remedies," published and presented at the AIAA World Congress in Anaheim CA, on October 15, 1997.(1) C1 NASA, Goddard Space Flight Ctr, Component Technol & Radiat Effects Branch, Greenbelt, MD 20771 USA. RP Ott, MN (reprint author), NASA, Goddard Space Flight Ctr, Component Technol & Radiat Effects Branch, Code 562, Greenbelt, MD 20771 USA. NR 0 TC 17 Z9 17 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 0-8194-2895-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3440 BP 37 EP 46 DI 10.1117/12.326697 PG 10 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BM19V UT WOS:000078010000004 ER PT S AU Ott, MN Bretthauer, JW AF Ott, MN Bretthauer, JW BE Taylor, EW TI Twelve channel optical fiber connector assembly: from commercial off the shelf to space flight use SO PHOTONICS FOR SPACE ENVIRONMENTS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photonics for Space Environments VI CY JUL 22, 1998 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE ribbon cable; MTP; array connector; fiber optic; space flight; parallel FODB; COTS; communications; interconnection; technology validation AB The commercial off the shelf(COTS) twelve channel optical fiber MTP array connector and ribbon cable assembly is being validated for space flight use and the results of this study to date are presented here. The interconnection system implemented for the Parallel Fiber Optic Data Bus (PFODB) physical layer will include a 100/140 micron diameter optical fiber in the cable configuration among other enhancements. As part of this investigation, the COTS 62.5/125 micron optical fiber cable assembly has been characterized for space environment performance as a baseline for improving the performance of the 100/140 micron diameter ribbon cable for the Parallel FODB application Presented here are the testing and results of random vibration and thermal environmental characterization of this commercial off the shelf(COTS) MTP twelve channel ribbon cable assembly. This paper is the first in a series of papers which will characterize and document the performance of Parallel FODB's physical layer from COTS to space flight worthy. C1 NASA, Goddard Space Flight Ctr, Swales Aerosp, Greenbelt, MD 20771 USA. RP Ott, MN (reprint author), NASA, Goddard Space Flight Ctr, Swales Aerosp, Code 562, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 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 0-8194-2895-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3440 BP 57 EP 68 DI 10.1117/12.326699 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BM19V UT WOS:000078010000006 ER PT S AU Leviton, DB AF Leviton, DB BE Taylor, EW TI New ultra-high sensitivity, absolute, linear, and rotary encoders SO PHOTONICS FOR SPACE ENVIRONMENTS VI SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Photonics for Space Environments VI CY JUL 22, 1998 CL SAN DIEGO, CA SP Soc Photo Opt Instrumentat Engineers DE encoder; linear encoder; rotary encoder; absolute encoder; polygon mirror; image centroid; pattern recognition AB Several new types of absolute optical encoders of both rotary and linear function are discussed. The means for encoding are complete departures from conventional optical encoders and offer advantages of reliability, compact form, immunity to damage-induced dropouts of position information, and about an order of magnitude higher sensitivity over what is commercially available. Rotary versions have sensitivity from 0.02 arcseconds down to 0.003 arcsecond while linear models have demonstrated sensitivity of 10 nm (0.01 mu m) with higher sensitivities possible. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2895-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3440 BP 100 EP 111 DI 10.1117/12.326695 PG 12 WC Engineering, Aerospace; Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BM19V UT WOS:000078010000010 ER PT J AU Brandt, S Priedhorsky, WC Fenimore, EE Moss, CE Black, K Kelley, RL Stillwell, D Birsa, F Borozdin, KN Kaniovsky, A Arefiev, VA Efremov, V AF Brandt, S Priedhorsky, WC Fenimore, EE Moss, CE Black, K Kelley, RL Stillwell, D Birsa, F Borozdin, KN Kaniovsky, A Arefiev, VA Efremov, V TI The MOXE all sky X-ray monitor SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT Nordic Conference in Theoretical High Energy Astrophysics CY SEP 14-16, 1997 CL COPENHAGEN, DENMARK SP Danish Space Res Inst, Nord Inst Theoret Phys, Nord Acad Adv Study ID TRANSIENT AB MOXE (MOnitoring X-ray Experiment) is the all-sky X-ray monitor on the Spectrum-X-Gamma astrophysical observatory. The six MOXE pinhole cameras will enable almost continous observation of more than 95% of the sky in the 2-25 keV energy band. The scientific objectives of MOXE are to detect transient X-ray sources for follow-up by instruments on SXG or by other observers, as well as to study the time variability of X-ray sources. With a sensitivity of approximate to 3 mCrab (5 sigma) most of the observed persistent sources will be Galactic X-ray binaries. MOXE will be well suited as a partner in multi-wavelength campaigns. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. IKI, Moscow, Russia. RP Brandt, S (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM sbrandt@lanl.gov RI Kelley, Richard/K-4474-2012; OI Priedhorsky, William/0000-0003-0295-9138 NR 21 TC 1 Z9 1 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1998 VL T77 BP 21 EP 24 DI 10.1088/0031-8949/1998/T77/003 PG 4 WC Physics, Multidisciplinary SC Physics GA 150TA UT WOS:000077680300005 ER PT J AU Vedrenne, G Jean, P Kandel, B Albernhe, F Borrel, V Mandrou, P Roques, JP von Ballmoos, P Durouchoux, P Cordier, B Diallo, N Schonfelder, V Lichti, GG Diehl, R Varendorff, M Strong, AW Georgii, R Teegarden, BJ Naya, J Seifert, H Sturner, S Matteson, J Lin, R Slassi, S Sanchez, F Caraveo, P Leleux, P Skinner, GK Connell, P AF Vedrenne, G Jean, P Kandel, B Albernhe, F Borrel, V Mandrou, P Roques, JP von Ballmoos, P Durouchoux, P Cordier, B Diallo, N Schonfelder, V Lichti, GG Diehl, R Varendorff, M Strong, AW Georgii, R Teegarden, BJ Naya, J Seifert, H Sturner, S Matteson, J Lin, R Slassi, S Sanchez, F Caraveo, P Leleux, P Skinner, GK Connell, P TI The SPI Spectrometer for the integral mission SO PHYSICA SCRIPTA LA English DT Article; Proceedings Paper CT Nordic Conference in Theoretical High Energy Astrophysics CY SEP 14-16, 1997 CL COPENHAGEN, DENMARK SP Danish Space Res Inst, Nord Inst Theoret Phys, Nord Acad Adv Study ID SIMULATIONS AB SPI (Spectrometer for INTEGRAL) is a high spectral resolution gamma-ray telescope to be flown on board the ESA mission INTEGRAL. It consists of an array of 19 closely packed Germanium detectors surrounded by an active anticoincidence shield of EGO. The imaging capabilities of the instrument are obtained with a tungsten coded aperture mask located 1.7 m from the Ge array. The fully coded field-of-view is 16 degrees and the angular resolution approximate to 2 degrees. The energy range extends from 20 keV to 8 MeV with a typical energy resolution approximate to 2 keV at 1 MeV. The point-source narrow-line sensitivity is estimated to be (3-7) x 10(-6) ph/cm(-2) s(-1) over most of the energy range of the instrument (E > 200 keV) for a 10(6) s observing time. With these expected performances a major step forward can be expected in fine gamma-ray spectroscopy of astrophysical objects. C1 CESR, F-31028 Toulouse 4, France. Ctr Etud Saclay, SAp, F-91191 Gif Sur Yvette, France. MPE, D-85748 Munich, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA USRA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Univ Valencia, IFIC, E-46100 Burjassot, Spain. CNR, IFC, I-20133 Milan, Italy. Univ Catholique Louvain, Inst Phys Nucl, B-1348 Louvain, Belgium. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. RP Vedrenne, G (reprint author), CESR, 9 Av Colonel Roche,BP 4346, F-31028 Toulouse 4, France. OI Caraveo, Patrizia/0000-0003-2478-8018 NR 10 TC 4 Z9 4 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1998 VL T77 BP 35 EP 38 DI 10.1088/0031-8949/1998/T77/009 PG 4 WC Physics, Multidisciplinary SC Physics GA 150TA UT WOS:000077680300011 ER PT J AU Birn, J Hesse, M AF Birn, J Hesse, M TI Substorm dynamics in the magnetotail SO PHYSICA SCRIPTA LA English DT Article ID THIN CURRENT SHEETS; TAIL CURRENT DISRUPTION; FIELD-ALIGNED CURRENTS; PLASMA SHEET; GROWTH-PHASE; ION; RECONNECTION; MECHANISM; REGION; MODEL AB The large-scale dynamic evolution of the magnetotail in relation to substorms is most commonly understood and described in terms of magnetic reconnection, neutral line formation, and plasmoid ejection into the distant tail as wall as current disruption and diversion in the inner tail. Recent magnetohydrodynamic simulations have shown that the two aspects, which are often considered as alternative models, may well he part of one unstable process. We review the most recent update of this model A new element, which has been strongly emphasized recently by observations as well as simulations, is the formation of a thin current sheet in the inner tail during the late substorm growth phase. This presumably eases the onset of instability, although the actual mechanism has not been clearly identified. The basic concept of a large-scale instability, involving the local breakdown of ideal MHD, has not changed significantly. However, recent MHD simulations as well as test particle investigations have put mom emphasis on the role of the near tail region in providing current diversion ("disruption") and particle acceleration. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Birn, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Hesse, Michael/D-2031-2012 NR 41 TC 0 Z9 0 U1 0 U2 1 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1998 VL T74 BP 58 EP 62 DI 10.1088/0031-8949/1998/T74/011 PG 5 WC Physics, Multidisciplinary SC Physics GA YU112 UT WOS:000071683000013 ER PT J AU Hesse, M Winske, D Birn, J AF Hesse, M Winske, D Birn, J TI On the ion-scale structure of thin current sheets in the magnetotail SO PHYSICA SCRIPTA LA English DT Article ID GROWTH-PHASE; SUBSTORM AB A numerical and analytical investigation of the formation and structure of thin current sheets which form in a magnetotail-like plasma model is presented. Current sheet formation is driven by the application of a boundary electric field similar to what would be expected from solar wind driving. As a result, a thin current sheet forms which involves strong Hall-type electric fields, which, by means of electric field drifts, strongly increase the electron contribution, and reduce the ion contribution to the cross-tail current density. This result is also supported by analytical investigations of the total plasma momentum. The thin current sheet forms on strong gradients in the ion density and the magnetic field. The simulation leads to a well defined equilibrium state. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hesse, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Michael.Hesse-1@gsfc.nasa.gov RI Hesse, Michael/D-2031-2012 NR 11 TC 14 Z9 14 U1 0 U2 2 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1998 VL T74 BP 63 EP 66 DI 10.1088/0031-8949/1998/T74/012 PG 4 WC Physics, Multidisciplinary SC Physics GA YU112 UT WOS:000071683000014 ER PT J AU Lakhina, GS Tsurutani, BT AF Lakhina, GS Tsurutani, BT TI Explosive energy release by disruption of current sheets SO PHYSICA SCRIPTA LA English DT Article ID ION-TEARING INSTABILITY; EARTHS MAGNETOTAIL; RECONNECTION; ORIGIN; CORONA; PHASE; TAIL; FLOW AB Current sheets can occur in almost all cosmic plasmas like planetary magnetospheres, stars, and galaxies. The disruption of current sheets releases the excess magnetic energy stored in the plasma system via magnetic reconnection. Ion tearing mode instability can cause spontaneous disruption of the forced current sheets. It is found that trapped electrons have a strong stabilizing effect on the excitation of this instability. The presence of background turbulence can effectively lead to the untrapping of the electron orbits and thus, facilitate excitation of ion tearing instability. The role of current sheet disruptions in magnetospheric substorms, solar flares and coronal transients are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. Indian Inst Geomagnetism, Bombay 400005, Maharashtra, India. RP Lakhina, GS (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91009 USA. RI Lakhina, Gurbax /C-9295-2012 NR 26 TC 2 Z9 2 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PY 1998 VL T74 BP 67 EP 70 DI 10.1088/0031-8949/1998/T74/013 PG 4 WC Physics, Multidisciplinary SC Physics GA YU112 UT WOS:000071683000015 ER PT J AU Van Keuls, FW Dahm, AJ AF Van Keuls, FW Dahm, AJ TI Experimental evidence for correlated hopping in two dimensions SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH LA English DT Article; Proceedings Paper CT 7th International Conference on Hopping and Related Phenomena (HRP7) CY AUG 19-22, 1997 CL RACKEVE, HUNGARY ID DISORDERED SYSTEMS; COULOMB GAP; CONDUCTIVITY AB The ratio C-2/beta, where C and beta are constants associated with variable-range hopping, is determined by requiring a smooth variation of the localization length with density in the transition region from ES hopping to screened Mott hopping. A reduction of the ratio C-2/beta from the single-particle hopping value is presented as evidence for correlated hopping in two dimensions. C1 Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. RP Van Keuls, FW (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 12 TC 2 Z9 2 U1 1 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0370-1972 J9 PHYS STATUS SOLIDI B JI Phys. Status Solidi B-Basic Res. PD JAN PY 1998 VL 205 IS 1 BP 21 EP 23 DI 10.1002/(SICI)1521-3951(199801)205:1<21::AID-PSSB21>3.0.CO;2-# PG 3 WC Physics, Condensed Matter SC Physics GA YU250 UT WOS:000071697300008 ER PT J AU Wilkinson, RA Zimmerli, GA Hao, H Moldover, MR Berg, RF Johnson, WL Ferrell, RA Gammon, RW AF Wilkinson, RA Zimmerli, GA Hao, H Moldover, MR Berg, RF Johnson, WL Ferrell, RA Gammon, RW TI Equilibration near the liquid-vapor critical point in microgravity SO PHYSICAL REVIEW E LA English DT Article ID TEMPERATURE PROPAGATION; SULFUR-HEXAFLUORIDE; PURE FLUID; FLUCTUATIONS; VISCOSITY; GRAVITY; REGION; RANGE; XENON; SF6 AB We used interferometry to measure the density changes associated with the late stage of thermal equilibration near the liquid-vapor critical point of SF6. This experiment was performed on board the Space Shuttle in the absence of the considerable obscuring effects of gravity. The density changes were analyzed in terms of the exponentially decaying modes predicted by a model for heat diffusion in an isothermal container. The time constants depended only on the temperature and not on the sample's history. In the temperature range from T-c+98 mK to T-c+28 mK, where T-c=319 K is the critical temperature, the values of the thermal diffusivity D-T derived from the time constants at each temperature are consistent with the values of D-T found by previous dynamic light-scattering measurements. From T-c+9 mK to T-c+1.4 mK, where Earth-based measurements of D-T are unavailable, the measured values of D-T agree with an asymptotically correct extrapolation of D-T closer to T-c. These data confirm our understanding of thermal equilibration in a range of T-T-c, when measurements on Earth are severely influenced by gravitationally induced convection and stratification of the sample. C1 NASA, Lewis Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. NYMA Inc, Brook Pk, OH 44142 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Westminister Coll, Dept Phys, New Wilmington, PA 16172 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Wilkinson, RA (reprint author), NASA, Lewis Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RI Moldover, Michael/E-6384-2013 NR 39 TC 32 Z9 32 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JAN PY 1998 VL 57 IS 1 BP 436 EP 448 DI 10.1103/PhysRevE.57.436 PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA YT413 UT WOS:000071600400058 ER PT S AU Ning, CZ AF Ning, CZ BE Osinski, M Blood, P Ishibashi, A TI Temperature induced alpha factor SO PHYSICS AND SIMULATION OF OPTOELECTRONIC DEVICES VI, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Physics and Simulation of Optoelectronic Devices CY JAN 26-30, 1998 CL SAN JOSE, CA SP SPIE DE plasma heating; thermal effects; line width enhancement factor; semiconductor lasers; optical gain and refractive index AB We study the temperature effects on gain, refractive index, and the linewidth enhancement ( or alpha) factor in a 2D semiconductor. We consider both the standard alpha factor due to carrier density variation and that due to temperature variation. The so-called total alpha factor due to both carrier density and temperature is also studied. As a result of temperature change, the alpha factors can be positive, negative, or zero. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Ning, CZ (reprint author), NASA, Ames Res Ctr, M-S T27A-1, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 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 0-8194-2722-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3283 BP 406 EP 410 DI 10.1117/12.316690 PN 1-2 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Multidisciplinary SC Engineering; Optics; Physics GA BL42A UT WOS:000075444100041 ER PT S AU Venturini, CC Spann, JF Comfort, RH AF Venturini, CC Spann, JF Comfort, RH BE Horanyi, M Robertson, S Walch, B TI Preliminary results from a laboratory study of charging mechanisms in a dusty plasma SO PHYSICS OF DUSTY PLASMAS: SEVENTH WORKSHOP SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 7th Workshop on the Physics of Dusty Plasmas CY APR, 1998 CL BOULDER, CO AB A laboratory investigation has been developed to experimentally study the interaction of micron sized particles with plasmas and electromagnetic radiation. The intent is to investigate under what conditions particles of various compositions and sizes become charged, or discharged, while exposed to an electron beam. Primary emphasis in this report is on secondary emission of electrons. Preliminary results are presented. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. Univ Alabama, Ctr Space Plasma & Aeronom Res, Huntsville, AL 35899 USA. RP Venturini, CC (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-809-6 J9 AIP CONF PROC PY 1998 VL 446 BP 73 EP 80 PG 8 WC Astronomy & Astrophysics; Physics, Applied; Physics, Fluids & Plasmas SC Astronomy & Astrophysics; Physics GA BM12X UT WOS:000077726800009 ER PT S AU Dutta, SB Mott, DB Brekosky, RP Kelly, RL Stahle, CK AF Dutta, SB Mott, DB Brekosky, RP Kelly, RL Stahle, CK BE Kumar, V Agarwal, SK TI Fabrication of a 6x6 array of silicon micro-calorimeters for x-ray spectroscopy SO PHYSICS OF SEMICONDUCTOR DEVICES, VOLS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT IX International Workshop on the Physics of Semiconductor Devices (IWPSD) CY DEC 16-20, 1997 CL DELHI, INDIA SP Solid State Phys Lab, Jamia Millia Islamia, Indian Inst Technol, Delhi, Def Res & Dev Org, India, Dept Electr, India, Dept Sci & Technol, India, Council Sci & Ind Res, India, All India Council Tech Educat, India, Soc Photo Opt Instrumentat Engineers, US, Int Ctr Theoret Phys, Italy, Aixtron Semiconductor Technol GmbH, Germany, Harley Instruments, India, ASM Lithog, US, Rockwell Sci Ctr, US, SIMCO Sci Instruments Mkt Co P Ltd, India, Keithley Instruments, India, Semiconductor Complex Ltd, India AB A 6X6 array of cryogenically cooled silicon micro-calorimeters has been designed and fabricated at the Goddard Space Flight Center/NASA for use in X-ray spectroscopy. The detectors show a resolution of the order of 10 eV over its detection range of 0.4-10 keV. Details of the design criteria and the fabrication process will be discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Dutta, SB (reprint author), NASA, Goddard Space Flight Ctr, Code 718-1, Greenbelt, MD 20771 USA. RI Kelley, Richard/K-4474-2012 NR 0 TC 2 Z9 2 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 0-8194-2756-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3316 BP 509 EP 512 PG 4 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Optics; Physics, Condensed Matter SC Engineering; Materials Science; Optics; Physics GA BL03H UT WOS:000074086700092 ER PT S AU Aslam, S Das, NC Jhabvala, M Shu, P AF Aslam, S Das, NC Jhabvala, M Shu, P BE Kumar, V Agarwal, SK TI Optimization of CCD fabrication process for space application SO PHYSICS OF SEMICONDUCTOR DEVICES, VOLS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT IX International Workshop on the Physics of Semiconductor Devices (IWPSD) CY DEC 16-20, 1997 CL DELHI, INDIA SP Solid State Phys Lab, Jamia Millia Islamia, Indian Inst Technol, Delhi, Def Res & Dev Org, India, Dept Electr, India, Dept Sci & Technol, India, Council Sci & Ind Res, India, All India Council Tech Educat, India, Soc Photo Opt Instrumentat Engineers, US, Int Ctr Theoret Phys, Italy, Aixtron Semiconductor Technol GmbH, Germany, Harley Instruments, India, ASM Lithog, US, Rockwell Sci Ctr, US, SIMCO Sci Instruments Mkt Co P Ltd, India, Keithley Instruments, India, Semiconductor Complex Ltd, India AB There exists a need to design small spectrometers for space sensor applications. Designing a small spectrometer requires a detector array with narrow pixels to meet the smaller grating periodicity. At Goddard Space Flight Center, an interleaved 512 pixel linear array with 200 mu m X 6 mu m pinned photo diode (PD) sensing sites and 500 mu m X 20 mu m CCD readout resistors have been designed and fabricated. Challenges arising in the design and processing of this detector are associated with the full well capacity of the odd shaped photo diode, and with the efficiency of charge transfer from photo diode to CCD storage area. By optimizing pinning implant process in PD area and using suitable transfer gate voltages the desired PD signal level of 6 Me-1 was achieved. C1 Hughes STX Corp, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Solid State Device Branch, Greenbelt, MD 20770 USA. RP Aslam, S (reprint author), Hughes STX Corp, 4400 Forbes Blvd, Lanham, MD 20706 USA. RI Aslam, Shahid/D-1099-2012 NR 0 TC 0 Z9 0 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 0-8194-2756-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3316 BP 588 EP 591 PG 4 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Optics; Physics, Condensed Matter SC Engineering; Materials Science; Optics; Physics GA BL03H UT WOS:000074086700105 ER PT J AU Bishop, J Romani, PN Atreya, SK AF Bishop, J Romani, PN Atreya, SK TI Voyager 2 ultraviolet spectrometer solar occultations at Neptune: photochemical modeling of the 125-165 nm lightcurves SO PLANETARY AND SPACE SCIENCE LA English DT Article ID ABSOLUTE RATE-CONSTANT; TEMPERATURE-DEPENDENCE; STRATOSPHERIC TEMPERATURE; THERMAL-DECOMPOSITION; PHOTO-DISSOCIATION; VACUUM-ULTRAVIOLET; UPPER-ATMOSPHERE; CROSS-SECTIONS; KINETIC DATA; ACETYLENE AB Ingress and egress Voyager 2 ultraviolet spectrometer (UVS) solar occultation lightcurves at wavelengths longward of HI Lyman alpha acquired during the Neptune encounter are compared with one-dimensional methane photochemical-transport models to infer hydrocarbon abundances and the strength of eddy mixing in the stratosphere. Previous modeling of the 125-140 nm lightcurves indicated eddy mixing coefficient (K) values of 3-10 x 10(6) cm(2) s(-1) near the 0.2 mu bar level and methane mixing ratios in the lower stratosphere on the order of 1-3 x 10(-4); these results should be insensitive to photochemical details, provided methane is the main source of opacity at these wavelengths. The UVS lightcurves at the longer wavelengths, which probe beneath the CH(4) photolysis peak, are expected to be dominated by the opacity of C(2) species (ethane, acetylene, ethylene) and perhaps higher order organics. At wavelengths > 152 nm, H(2) Rayleigh scattering is also a major opacity source. Modeled C(2) species abundances are sensitive to modeling details, especially the strength and height profile of eddy mixing. The current photochemical model incorporates several updates, including a recent revision in CH(4) photolysis branching ratios at Lyman alpha. In the photochemical modeling reported here, various forms for the eddy mixing profile have been tested, with the constraint that the models for egress conditions remain consistent with the C(2)H(6) and C(2)H(2) abundances near 0.5 mbar derived from IRIS measurements. Superior fits are obtained with models exhibiting a stagnant lower stratosphere (K approximate to 2 x 10(3) cm(2) s(-1) for pressures > 2 mbar) with a rapid transition to a localized level of vigorous eddy mixing in the upper stratosphere (K approximate to 10(8) cm(2) s(-1) near 10 mu bar, decreasing at higher altitudes). In line with our earlier work, methane mixing ratios on the order of 10(-4) are required to obtain good agreement between the photochemical models and the UVS lightcurves. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Computat Phys Inc, Fairfax, VA 22031 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Bishop, J (reprint author), Computat Phys Inc, 2750 Prosper Ave,Suite 600, Fairfax, VA 22031 USA. RI Romani, Paul/D-2729-2012 NR 89 TC 25 Z9 25 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN PY 1998 VL 46 IS 1 BP 1 EP 20 DI 10.1016/S0032-0633(97)00126-8 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ103 UT WOS:000073179800001 ER PT J AU Sekanina, Z Chodas, PW Yeomans, DK AF Sekanina, Z Chodas, PW Yeomans, DK TI Secondary fragmentation of comet Shoemaker-Levy 9 and the ramifications for the progenitor's breakup in July 1992 SO PLANETARY AND SPACE SCIENCE LA English DT Article ID NUCLEI; DENSITY; IMPACTS; JUPITER; MODEL; SIZE AB Comprehensive analysis of discrete events of secondary fragmentation leads to a conceptually new understanding of the process of disintegration of comet Shoemaker-Levy 9. We submit that the jovian tidal forces inflicted extensive cracks throughout the interior of the original nucleus but did not split it apart. The initial disruption was apparently accomplished by stresses exerted on the cracked object by its fast rotation during the early post-perijove period of time. We argue that this disruption was in fact a rapid sequence of episodes during July 1992 that gave birth to the 12 on-train, or primary, fragments: A, C, D, E, G, H, K, L, Q (later Q(1)), R, S, and W. The discrete events of secondary fragmentation, which gave birth to the off-train fragments, are understood in this scenario as stochastic manifestations of the continuing process of progressive disintegration. Of the 13 off-train fragments considered, nine were secondary-B, F, G(2), M, N, P (later P-2 or P-2a), Q(2), U, and V-and four tertiary (J, P-1, P-2b, and T). The separation parameters of 11 off-train fragments were determined. The vectorial distribution of separation velocities of these fragments shows a strong concentration toward a great circle, unquestionably an effect of the approximately conserved angular momentum of the progenitor comet since the time of its initial disruption. Also apparent is their clumping (except for P-1) to a segment along the great circle, implying that the fragments were consistently released from one side of their parents, thus explaining for the first time why the off-train fragments preferentially appeared on one side of the nuclear train. In order to obtain a consistent solution, our model requires that the points of separation be on the antisolar side of the parent fragments, where thermal stresses are likely to enhance the effect of rotation. The episodes of secondary fragmentation are found to have occurred in a period of time from a few weeks to at least nine months after the close encounter with Jupiter in early July 1992, and the separation velocities ranged between 0.36 and 1.7 m s(-1). The spin-axis position is determined to have been nearly in the jovicentric orbit plane, which rules out the Asphaug-Benz-Solem strengthless aggregate model as a plausible breakup hypothesis; Since the separation velocities are rotational in nature, they cannot substantially exceed the critical limit for centrifugal breakup and offer an estimate for the original nuclear dimensions. The comet's nucleus is found to have been approximately 10 km in diameter and spinning rapidly. With the exception of P-1, and apparently also P-2 and F, no nongravitational deceleration was detected in the motions of the off-train fragments. Serious doubts are cast on continuing appreciable activity of any of these fragments. Indeed, when it was necessary to introduce a deceleration into the equations of motion, the effect appears to have been due to the action of solar radiation pressure on the centroid of centimeter-sized particulates in the disintegrating condensations. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 34 TC 17 Z9 17 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JAN PY 1998 VL 46 IS 1 BP 21 EP 45 DI 10.1016/S0032-0633(97)00115-3 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ103 UT WOS:000073179800002 ER PT J AU McKenna-Lawlor, S Afonin, VV Kirsch, E Schwingenschuh, K Slavin, JA Trotignon, JG AF McKenna-Lawlor, S Afonin, VV Kirsch, E Schwingenschuh, K Slavin, JA Trotignon, JG TI An overview of energetic particles (from 55 keV to > 30 MeV) recorded in the close Martian environment, and their energization in local and external processes SO PLANETARY AND SPACE SCIENCE LA English DT Article ID SOLAR-WIND INTERACTION; PLASMA-WAVE SYSTEM; BOW SHOCK POSITION; PHOBOS MISSION; TERRESTRIAL PLANETS; 1ST MEASUREMENTS; MARS; MAGNETOSPHERE; IONS; SPACE AB Observations made by the SLED particle : detector on Phobos-2 in the close Martian environment from 29 January to 27 March, 1989 during the early rising phase of Solar Cycle 22, show the frequent presence close to the planet, under reasonably "quiet" interplanetary conditions, of particles with energies (E) in the range from several tens of, to several hundred, keV. Under disturbed interplanetary circumstances, particles reaching energies of several tens of MeV were recorded close to Mars. Those particles in the keV range were observed at well-defined locations, i.e. at the Terminator Shocks (E up to approximate to 600 keV); just inside the subsolar Planetopause (E up to approximate to 225 keV), and travelling down the Tail, E greater than or equal to 55 keV. These three populations are herein suggested, instancing various candidate mechanisms, to have been energized by processes local to the planet. Since the seed particles for ions accelerated at the Terminator Shocks may comprise ambient, pre-accelerated, solar particles, the energies of ions detected by SLED during Bow Shock transits was observed (during two months) to vary between approximate to 50 keV and approximate to 600 keV. Particles with energies up to several tens of MeV which were found to suffuse the close planetary environment over extended periods, are interpreted to have been produced in association with solar processes external to Mars (Co-rotating Interaction Regions; Gradual and Impulsive Solar Events). Particle enhancements in the keV range recorded by SLED (under favourable magnetic conditions) during Bow Shock traversals, provide topographical information concerning the location of the Martian subsolar and distant shock surfaces. These observations constitute a new data set, complementary to those determinations of key boundaries derived from plasma and magnetic field measurements made aboard various American and Russian spacecraft at Mars which, for more than thirty years now, have been generally used in modelling the Solar Wind interaction with the planet. Three-dimensional measurements made at low altitudes over long dwell times are presently required to provide further insights into those local processes whereby populations of keV particles discovered in SLED data, close to the inbound Planetopause and travelling down the Tail, are individually energized. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 St Patricks Coll, Space Technol Ireland, Maynooth, Kildare, Ireland. Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. Max Planck Inst Aeron, W-3411 Katlenburg Lindau, Germany. Inst Weltraumforsch, A-8010 Graz, Austria. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. CNRS, Lab Phys Chim Environm, F-45071 Orleans, France. RP McKenna-Lawlor, S (reprint author), St Patricks Coll, Space Technol Ireland, Maynooth, Kildare, Ireland. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 70 TC 6 Z9 6 U1 2 U2 2 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 JAN PY 1998 VL 46 IS 1 BP 83 EP 102 DI 10.1016/S0032-0633(97)00139-6 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZJ103 UT WOS:000073179800005 ER PT B AU Meyyappan, M Bose, D Hash, D Hwang, H Govindan, TR AF Meyyappan, M Bose, D Hash, D Hwang, H Govindan, TR BE Mathad, GS Misra, D Sundaram, KB TI Plasma modeling as a design tool in microelectronics manufacturing SO PLASMA PROCESSING XII SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 12th International Symposium on Plasma Processing at 193rd Meeting of the Electrochemical-Society CY MAY 03-08, 1998 CL SAN DIEGO, CA SP Electrochem Soc, Dielect Sci & Technol & Electr Div AB Modeling of plasma processes used in integrated circuit manufacturing has been maturing rapidly. This article provides a review of the current status in plasma modeling, covering reactor models, feature evolution models and database needs. Results from the NASA Ames group on all of these areas are presented and a discussion on future needs and directions is provided. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Meyyappan, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-198-6 J9 ELEC SOC S PY 1998 VL 98 IS 4 BP 43 EP 56 PG 14 WC Electrochemistry; Engineering, Electrical & Electronic SC Electrochemistry; Engineering GA BL67T UT WOS:000076294100006 ER PT J AU Connell, JW Smith, JG Kalil, CG Siochi, EJ AF Connell, JW Smith, JG Kalil, CG Siochi, EJ TI The effect of low Earth orbit atomic oxygen exposure on phenylphosphine oxide-containing poly(arylene ether)s SO POLYMERS FOR ADVANCED TECHNOLOGIES LA English DT Article DE phenylphosphineoxide-containing poly(aryleneether)s; LEO exposure; atomic oxygen exposure; atomic oxygen resistant polymers ID CONTAINING POLYIMIDES; PLASMA; HETEROCYCLE)S; POLYMERS; FILMS AB Unoriented thin films Of phenylphosphine oxine-containing poly(arylene ether)s were exposed to low Earth orbit aboard the space shuttle Atlantis (STS-51) as part of a flight experiment designated Limited Duration Candidate Exposure (LDCE 4-5). The samples were exposed to primarily atomic oxygen (similar to 7 x 10(19) atoms/cm(2)). Based on post-flight analyses using atomic force microscopy, X-ray photoelectron spectroscopy, gel permeation chromatography and weight loss data, it was proposed that atomic oxygen exposure of these materials produces a phosphate layer at the surface of the samples, apparently by the reaction of atomic oxygen with the phosphorus in the polymer backbone. Ground-based oxygen plasma exposure experiments have previously shown that this phosphate layer provides a barrier against further attack by atomic oxygen [1]. The results obtained from these analyses compare favorably with those obtained fi om samples exposed to an oxygen plasma in ground-based exposure experiments [1]. (C) 1998 John Wiley & Sons, Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. Lockheed Engn & Sci Co, Hampton, VA 23666 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 36 TC 26 Z9 26 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1042-7147 J9 POLYM ADVAN TECHNOL JI Polym. Adv. Technol. PD JAN PY 1998 VL 9 IS 1 BP 11 EP 19 DI 10.1002/(SICI)1099-1581(199801)9:1<11::AID-PAT728>3.3.CO;2-K PG 9 WC Polymer Science SC Polymer Science GA YU426 UT WOS:000071715900003 ER PT J AU Young, PR Slemp, WS AF Young, PR Slemp, WS TI The performance of selected polymeric materials exposed to low earth orbit SO POLYMERS FOR ADVANCED TECHNOLOGIES LA English DT Article DE LEO environmental effects; polymer characterization; solution property measurements; long duration exposure facility (LDEF) AB The behavior of several polymeric materials given various exposures in lo ro Earth orbit was characterized by a number of analytical techniques including ultraviolet-visible and infrared spectroscopy, thermal analyses, selected microscopies, and solution property measurements. The materials were particularly susceptible to atomic oxygen-induced erosion, ultraviolet-induced degradation, and spacecraft-induced contamination. While no change was noted in glass transition temperature, various molecular weight parameters did change with exposure. The intent of the research is to enhance our fundamental understanding of space environmental effects on polymeric materials and benefit our ability to predict and improve their performance in selected applications. (C) 1998 John Wiley & Sons, Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Young, PR (reprint author), Emory & Henry Coll, Dept Chem, Emory, VA 24327 USA. NR 20 TC 7 Z9 7 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1042-7147 J9 POLYM ADVAN TECHNOL JI Polym. Adv. Technol. PD JAN PY 1998 VL 9 IS 1 BP 20 EP 23 DI 10.1002/(SICI)1099-1581(199801)9:1<20::AID-PAT729>3.0.CO;2-S PG 4 WC Polymer Science SC Polymer Science GA YU426 UT WOS:000071715900004 ER PT S AU Chen, LY Hunter, GW Neudeck, PG Knight, D AF Chen, LY Hunter, GW Neudeck, PG Knight, D BE Pearton, SJ Shul, RJ Wolfgang, E Ren, F Tenconi, S TI Surface and interface study of PdCr/SiC Schottky diode gas sensor annealed at 425 degrees C SO POWER SEMICONDUCTOR MATERIALS AND DEVICES SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Power Semiconductor Materials and Devices CY DEC 01-04, 1997 CL BOSTON, MA SP Mat Res Soc AB The surface and interface properties of a Pd0.9Cr0.1/SiC Schottky diode gas sensor both before and after annealing are investigated using Auger electron spectroscopy (AES), scanning electron spectroscopy (SEM), and energy dispersive spectroscopy (EDS). At room temperature the alloy reacted with SiC and formed Pd,Si only in a very narrow interfacial region. After annealing for 250 hours at 425 degrees C, the surface of Schottky contact area has much less silicon and carbon contamination than that found on the surface of an annealed Pd/SiC structure. Pd,Si formed at a broadened interface after annealing, but a significant layer of alloy film is still free of silicon and carbon. The chromium concentration with respect to palladium is quite uniform down to deep interface region. A stable catalytic surface and a clean layer of Pd0.9Cr0.1 film are likely responsible for significantly improved device sensitivity. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chen, LY (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-388-6 J9 MATER RES SOC SYMP P PY 1998 VL 483 BP 259 EP 264 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BK73W UT WOS:000073286800036 ER PT S AU Neudeck, PG Huang, W Dudley, M AF Neudeck, PG Huang, W Dudley, M BE Pearton, SJ Shul, RJ Wolfgang, E Ren, F Tenconi, S TI Breakdown degradation associated with elementary screw dislocations in 4H-SiC P+N junction rectifiers SO POWER SEMICONDUCTOR MATERIALS AND DEVICES SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Power Semiconductor Materials and Devices CY DEC 01-04, 1997 CL BOSTON, MA SP Mat Res Soc AB It is well-known that SIC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vector > 2c), 4H-SiC wafers and epilayers also contain elementary screw dislocations (i.e., Burgers vector = Ic with no hollow core) in densities on the order of thousands per cm(2), nearly 100-fold micropipe densities. This paper describes an initial study into the impact of elementary screw dislocations on the reverse-bias current-voltage CI-V) characteristics of 4H-SiC p(+)n diodes. First, Synchrotron White Beam X-ray Topography (SWBXT) was employed to map the exact locations of elementary screw dislocations within small-area 4H-SiC p(+)n mesa diodes. Then the high-field reverse leakage and breakdown properties of these diodes were subsequently characterized on a probing station outfitted with a dark box and video camera. Most devices without screw dislocations exhibited excellent characteristics, with no detectable leakage current prior to breakdown, a sharp breakdown I-V knee, and no visible concentration of breakdown current. In contrast devices that contained at least one elementary screw dislocation exhibited a 5% to 35% reduction in breakdown voltage, a softer breakdown I-V knee, and visible microplasmas in which highly localized breakdown current was concentrated. The locations of observed breakdown microplasmas corresponded exactly to the locations of elementary screw dislocations identified by SWBXT mapping. While not as detrimental to SiC device performance as micropipes, the undesirable breakdown characteristics of elementary screw dislocations could nevertheless adversely affect the performance and reliability of 4H-SiC power devices. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Neudeck, PG (reprint author), NASA, Lewis Res Ctr, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 22 Z9 22 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-388-6 J9 MATER RES SOC SYMP P PY 1998 VL 483 BP 285 EP 294 PG 10 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA BK73W UT WOS:000073286800040 ER PT B AU Safie, FM AF Safie, FM BE Mosleh, A Bari, RA TI An overview of quantitative risk assessment of space shuttle propulsion elements SO PROBABILISTIC SAFETY ASSESSMENT AND MANAGEMENT (PSAM 4), VOLS 1-4 LA English DT Proceedings Paper CT 4th International Conference on Probabilistic Safety Assessment and Management CY SEP 13-18, 1998 CL NEW YORK, NY SP Int Assoc Probabilist Safety Assessment & Management, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Civil Engineers, Amer Soc Mech Engineers, Atom Energy Soc Japan, European Nucl Soc, European Safety & Reliabil Assoc, Fed Aviat Adm, Human Factors Soc, Inst Elect & Electr Engineers, Int Atom Energy Agcy, European Union, Joint Res Ctr, NASA, Org Econ Cooperat & Dev, Soc Risk Analy, Syst Safety Soc, UK Safety & Reliabil Soc, US Coast Guard, US DOE, US Nucl Regulatory Commiss, Associated Univ Inc, Beta Corp Int, BOOZ ALLEN & HAMILTON Inc, Brookhaven Sci Associates, ERIN Engn & Res Inc, PLG Inc, Sci Applicat Int Corp, SCIENTECH INC, Univ Maryland, Ctr Technol Risk Stud AB This paper presents an overview of the application of the quantitative risk assessment (QRA) methods to the NASA Space Shuttle system. The NASA QRA application involves the development of a risk model for the overall Space Shuttle system. The model is intended to provide a tool to estimate Space Shuttle risk and to perform sensitivity analyses/trade studies, including the evaluation of Shuttle upgrades. Marshall Space Flight Center (MSFC) is part of the NASA team conducting the QRA study; MSFC responsibility involves modeling the propulsion elements of the Space Shuttle. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Safie, FM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 3-540-76262-0 PY 1998 BP 425 EP 430 PG 6 WC Engineering, Multidisciplinary; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA BP34L UT WOS:000084758100065 ER PT B AU Rutledge, PJ Weinstock, RM AF Rutledge, PJ Weinstock, RM BE Mosleh, A Bari, RA TI Quantitative Risk Assessment System (QRAS) SO PROBABILISTIC SAFETY ASSESSMENT AND MANAGEMENT (PSAM 4), VOLS 1-4 LA English DT Proceedings Paper CT 4th International Conference on Probabilistic Safety Assessment and Management CY SEP 13-18, 1998 CL NEW YORK, NY SP Int Assoc Probabilist Safety Assessment & Management, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Civil Engineers, Amer Soc Mech Engineers, Atom Energy Soc Japan, European Nucl Soc, European Safety & Reliabil Assoc, Fed Aviat Adm, Human Factors Soc, Inst Elect & Electr Engineers, Int Atom Energy Agcy, European Union, Joint Res Ctr, NASA, Org Econ Cooperat & Dev, Soc Risk Analy, Syst Safety Soc, UK Safety & Reliabil Soc, US Coast Guard, US DOE, US Nucl Regulatory Commiss, Associated Univ Inc, Beta Corp Int, BOOZ ALLEN & HAMILTON Inc, Brookhaven Sci Associates, ERIN Engn & Res Inc, PLG Inc, Sci Applicat Int Corp, SCIENTECH INC, Univ Maryland, Ctr Technol Risk Stud AB On July 29, 1996, the NASA Administrator directed the Associate Administrator, Office of Safety and Mission Assurance, and the Space Shuttle Program Manager to develop a quantified risk model in the form of a PC-based software tool that could be used to calculate the change in the probability of catastrophic failure of the Space Shuttle as a result of proposed upgrades. Over the course of the succeeding year, such a software application was developed by NASA Headquarters in conjunction with the Space Shuttle Program, Marshal Space Flight Center (MSFC), Johnson Space Center (JSC), and the University of Maryland; in early October, 1997, it was demonstrated to the NASA Administrator. It is called the Quantitative Risk Assessment System (QRAS). While QRAS was designed to be used for any engineered system; e.g., Space Shuttle, International Space Station, etc., most effort to date has gone into loading it with a comprehensive Space Shuttle risk model (Shuttle element and subsystems were modeled by MSFC and JSC). This paper describes QRAS, how it works, enhancements that are in work or planned, and how it can be used to support a NASA risk-based decision-making process for the Space Shuttle or other programs/projects. C1 NASA, Washington, DC 20546 USA. RP Rutledge, PJ (reprint author), NASA, Washington, DC 20546 USA. NR 1 TC 0 Z9 0 U1 1 U2 2 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 3-540-76262-0 PY 1998 BP 787 EP 792 PG 6 WC Engineering, Multidisciplinary; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA BP34L UT WOS:000084758100119 ER PT B AU Cornford, SL AF Cornford, SL BE Mosleh, A Bari, RA TI Managing risk as a resource using the defect detection and prevention process SO PROBABILISTIC SAFETY ASSESSMENT AND MANAGEMENT (PSAM 4), VOLS 1-4 LA English DT Proceedings Paper CT 4th International Conference on Probabilistic Safety Assessment and Management CY SEP 13-18, 1998 CL NEW YORK, NY SP Int Assoc Probabilist Safety Assessment & Management, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Civil Engineers, Amer Soc Mech Engineers, Atom Energy Soc Japan, European Nucl Soc, European Safety & Reliabil Assoc, Fed Aviat Adm, Human Factors Soc, Inst Elect & Electr Engineers, Int Atom Energy Agcy, European Union, Joint Res Ctr, NASA, Org Econ Cooperat & Dev, Soc Risk Analy, Syst Safety Soc, UK Safety & Reliabil Soc, US Coast Guard, US DOE, US Nucl Regulatory Commiss, Associated Univ Inc, Beta Corp Int, BOOZ ALLEN & HAMILTON Inc, Brookhaven Sci Associates, ERIN Engn & Res Inc, PLG Inc, Sci Applicat Int Corp, SCIENTECH INC, Univ Maryland, Ctr Technol Risk Stud AB NASA Code QE is funding a number of programs to develop and implement improvements in the efficacy and efficiency of Verification and Validation and Risk Management processes for space-flight projects. A physics-of-failure-based Defect Detection and Prevention (DDP) methodology has been developed and is currently being implemented on various JPL projects and as part of JPL's new model-based development environment. The DDP process weights the criticality of the various relevant failure modes by including the likelihood and impact on mission requirements. The net effectiveness of various subsets of PACTs (Preventative measures, Analyses, process Controls and Tests) can then be evaluated against these weighted failure modes to obtain the residual risk for each of these failure modes and the associated resource costs to achieve these risk levels. This identifies the project-relevant "tall pole" failure modes and design drivers and allows real time tailoring with the evolution of the design and technology content. The Defect Detection and Prevention methodology allows risk management in its truest sense: identifies and assesses risk, provides options and tools for risk decision making and mitigation and allows for real-time tracking of current risk status. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cornford, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 1 U2 1 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 3-540-76262-0 PY 1998 BP 1609 EP 1614 PG 6 WC Engineering, Multidisciplinary; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA BP34L UT WOS:000084758100243 ER PT B AU Hulet, MW Wright, GR AF Hulet, MW Wright, GR BE Mosleh, A Bari, RA TI Deleterious exposures to health and safety professionals SO PROBABILISTIC SAFETY ASSESSMENT AND MANAGEMENT (PSAM 4), VOLS 1-4 LA English DT Proceedings Paper CT 4th International Conference on Probabilistic Safety Assessment and Management CY SEP 13-18, 1998 CL NEW YORK, NY SP Int Assoc Probabilist Safety Assessment & Management, Amer Inst Chem Engineers, Amer Nucl Soc, Amer Soc Civil Engineers, Amer Soc Mech Engineers, Atom Energy Soc Japan, European Nucl Soc, European Safety & Reliabil Assoc, Fed Aviat Adm, Human Factors Soc, Inst Elect & Electr Engineers, Int Atom Energy Agcy, European Union, Joint Res Ctr, NASA, Org Econ Cooperat & Dev, Soc Risk Analy, Syst Safety Soc, UK Safety & Reliabil Soc, US Coast Guard, US DOE, US Nucl Regulatory Commiss, Associated Univ Inc, Beta Corp Int, BOOZ ALLEN & HAMILTON Inc, Brookhaven Sci Associates, ERIN Engn & Res Inc, PLG Inc, Sci Applicat Int Corp, SCIENTECH INC, Univ Maryland, Ctr Technol Risk Stud AB The desire to identify and quantify employee exposures to hazardous materials, lasers, noise, radiation, pressures, temperatures, and combinations associated with various gases, chemicals and wastes requires health and safety to be in the same environments where their subjects are thought to be a risk. Important questions need to be examined include: 1) whether these health and safety personnel are aware of the potential exposures which can result from the combinations of various gases, materials, and waste streams; 2) do they understand the essential requirements of personal protection not only for the employee but also, for themselves as they conduct their investigations; 3) is the correct instrumentation being used to determine the exposure levels? Additionally, are the other quasi-safety functions including fire protection, medical treatment, and medical research adequately informed by education and job training? A variety of cases involving health and safety professionals exposures are discussed in the paper which seem to indicate a need for reducing exposures. Latent effects of health exposures are more and more frequently resulting in the same lethal effects that we previously expected from acute exposures. Health and safety professionals don't have all of the data necessary to protect themselves adequately against latent as well as acute exposures. Does the level of commitment to the use of personal protective equipment by the health and safety personnel while they monitor others need to be examined? It is hoped that this paper will open up a discussion of these important questions. C1 Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hulet, MW (reprint author), Ames Res Ctr, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 3-540-76262-0 PY 1998 BP 2859 EP 2864 PG 6 WC Engineering, Multidisciplinary; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA BP34L UT WOS:000084758100432 ER PT B AU Semmel, GS Linton, DG AF Semmel, GS Linton, DG GP IEEE TI Determining optimal testing times for Markov Chain Usage Models SO PROCEEDINGS IEEE SOUTHEASTCON '98: ENGINEERING FOR A NEW ERA SE IEEE SOUTHEASTCON - CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE SOUTHEASTCON 98 - Engineering for a New Era CY APR 24-26, 1998 CL ORLANDO, FL SP IEEE Reg 3, IEEE Orlando Sect, IEEE Orlando Student Branch, Univ Cent Florida, Coll Engn DE statistical software testing; usage model AB Statistical software testing presents two difficulties for the tester: (1) establishing accurate user profiles (i.e. usage probabilities) and (2) incurring lengthy test times. An algorithm, named the Frequency Count Method (FCM), is developed which addresses both difficulties simultaneously. FCM finds usage probabilities within predetermined ranges and concurrently minimizes the amount of testing time. First, FCM randomly generates a large number of matrices for a given Markov chain with constrained usage probabilities. For each one-step transition matrix associated with the given Markov Chain Usage Model, FCM simulates the steps of the chain. FCM flags the usage matrix which requires the minimum expected amount of testing time (assuming no failures) and ensures theoretical and calculated stationary probability values are within some preset precision. Thus, by generating test sequences from the usage probabilities of the flagged matrix, expected minimum statistical testing time is achieved. This minimum time is optimal with respect to the transition probability ranges and the given execution times. Employing a 5-state usage model with numerical values for the transition probability bounds and code execution times, the FCM algorithm is illustrated and expected minimum testing time is calculated. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Semmel, GS (reprint author), NASA, DP-5, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 2 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4391-3 J9 IEEE SOUTH RECORD PY 1998 BP 1 EP 4 DI 10.1109/SECON.1998.673276 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BK95R UT WOS:000073940700001 ER PT B AU Graf, JE Tsai, WY Jones, L AF Graf, JE Tsai, WY Jones, L GP IEEE TI Overview of QuikSCAT mission - a quick deployment of a high resolution, wide swath scanning scatterometer for ocean wind measurement SO PROCEEDINGS IEEE SOUTHEASTCON '98: ENGINEERING FOR A NEW ERA SE IEEE SOUTHEASTCON - CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE SOUTHEASTCON 98 - Engineering for a New Era CY APR 24-26, 1998 CL ORLANDO, FL SP IEEE Reg 3, IEEE Orlando Sect, IEEE Orlando Student Branch, Univ Cent Florida, Coll Engn AB Scatterometer instruments are active microwave sensors that transmit a series of microwave pulses and measure the returned echo power to allow determination of the normalized radar backscattering cross section (sigma-0) of the ocean surface and, subsequently, the ocean wind speed and direction The NASA Scatterometer (NSCAT) was launched on board of the ADEOS in August 1996 and returned 10 months of high quality data before the failure of the ADEOS spacecraft terminated the data stream in June, 1997. Since the next scheduled NASA scatterometer mission, SeaWinds on ADEOS II, will be launched in mid-2000, NASA has approved a NSCAT replacement mission, called SeaWinds on QuikSCAT (QSCAT), to be launched in November 1998. The purpose of this paper is to provide a general description of the spacecraft system and the instrument design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Graf, JE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 10 Z9 10 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4391-3 J9 IEEE SOUTH RECORD PY 1998 BP 314 EP 317 DI 10.1109/SECON.1998.673359 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BK95R UT WOS:000073940700084 ER PT S AU Porter, JG Falconer, DA Moore, RL AF Porter, JG Falconer, DA Moore, RL GP EUROPEAN SPACE AGCY TI The magnetic roots of enhanced coronal heating in large loops and plumes SO PROCEEDINGS OF AN INTERNATIONAL MEETING ON SOLAR JETS AND CORONAL PLUMES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT International Meeting on Solar Jets and Coronal Plumes CY FEB 23-26, 1998 CL UNIV ANTILLES GUYANE, GUADELOUPE SP European Space Agcy, Inst Astrophys Paris, CNRS, COSTEP HO UNIV ANTILLES GUYANE AB The magnetic structure and activity at sites of enhanced heating in the solar atmosphere has been a primary interest of the solar group at MSFC. We review the results of a recent series of papers on this topic, concentrating on those aspects of the work relating to the heating of extended coronal magnetic structures. These studies have found that bright extended coronal structures, whether rooted in active regions or in quiet regions, are heated from active compact magnetic structures at their feet. We summarize the magnetic characteristics of these active footpoint sites, and examine the relationship that the changes in emission seen in them have to the changes in emission in the structures extending away from them. One unexpected result is the poor correlation of these variations. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Porter, JG (reprint author), NASA, George C Marshall Space Flight Ctr, ES 82, Huntsville, AL 35812 USA. NR 0 TC 5 Z9 5 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-684-8 J9 ESA SP PUBL PY 1998 VL 421 BP 147 EP 155 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL38L UT WOS:000075339900017 ER PT S AU Suess, ST AF Suess, ST GP EUROPEAN SPACE AGCY TI Models of plumes: Their flow, their geometric spreading, and their mixing with interplume flow SO PROCEEDINGS OF AN INTERNATIONAL MEETING ON SOLAR JETS AND CORONAL PLUMES SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT International Meeting on Solar Jets and Coronal Plumes CY FEB 23-26, 1998 CL UNIV ANTILLES GUYANE, GUADELOUPE SP European Space Agcy, Inst Astrophys Paris, CNRS, COSTEP HO UNIV ANTILLES GUYANE DE plumes; theory; MHD; Kelvin-Helmholtz AB There are two types of plume flow models: (i) 1D models using ad hoc spreading functions, f(r). (ii) MHD models. 1D models can be multifluid, time dependent, and incorporate very general descriptions of the energetics. They confirm empirical results that plume flow is slow relative to requirements for high speed wind. But, no published 1D model incorporates the rapid local spreading at the base (f(l)(r)) which has an important effect on mass flux. The one published MHD model is isothermal, but confirms that if beta=8 pi p/\B\(2)much less than 1 then the field is nearly potential below similar to 50,000 km. Building on the MHD result, we apply a two scale approximation to calculate f(l)(r). We also compute the global spreading (f(g)(r)) out to 5.0 R-SUN imposed by coronal hole geometry. Global MHD models provide a potent method of calculating f(g)(r). Unambiguous plume signatures have not yet been found in the solar wind. This is probably due to strong mixing of plume and interplume flows near the Sun. We describe a physical source for strong mixing due to the observed flows being unstable to shear instabilities that lead to rapid disruption. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Suess, ST (reprint author), NASA, George C Marshall Space Flight Ctr, ES82, Huntsville, AL 35812 USA. NR 0 TC 15 Z9 15 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-684-8 J9 ESA SP PUBL PY 1998 VL 421 BP 223 EP 230 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL38L UT WOS:000075339900026 ER PT S AU Mesbahi, M AF Mesbahi, M GP AMER AUTOMAT CONTROL COUNCIL TI On robustness measures and the feasible set of the LMI arising in the stability analysis SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS DE linear matrix inequalities; Lyapunov inequalities; robustness analysis AB We present a recent result in the area of algorithmic theory of stability and robustness. The emphasis will be placed on the relationship that exists between the size of the solution of an LMI which arise in the stability analysis on one hand, and the robustness property of the underlying system on the other. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Mesbahi, M (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 83 EP 84 PG 2 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200019 ER PT S AU Bayard, DS AF Bayard, DS GP AMER AUTOMAT CONTROL COUNCIL TI A modified augmented error algorithm for adaptive noise cancellation in the presence of plant resonances SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB A difficult and well-known problem for adaptive noise cancellation arises when there are plant resonances blocking the noise cancellation path. A new algorithm is proposed for this problem based on a modification of the Augmented Error algorithm of Monopoli. It is shown using a recently developed LTI analysis framework that the modified algorithm has several performance and robustness advantages over both the Filtered-X and Augmented Error algorithms for this class of problems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayard, DS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 137 EP 141 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200031 ER PT S AU Bayard, DS AF Bayard, DS GP AMER AUTOMAT CONTROL COUNCIL TI An exposure-dependent spacecraft pointing control criteria for high resolution spectroscopy SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB A new pointing control criteria is derived to support high resolution space spectroscopy. The criteria maps desired specifications on allowable flux offset (imposed by scientists for accurate calculation of spectral line ratios) into standard pointing control definitions in terms of bias and jitter. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayard, DS (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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 210 EP 214 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200047 ER PT S AU Belcastro, CM AF Belcastro, CM GP AMER AUTOMAT CONTROL COUNCIL TI Ensuring control integrity of critical systems subjected to electromagnetic disturbances: Problem overview SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB An assessment process for verifying the control integrity of critical flight systems in adverse, as well as nominal, operating environments is currently under development at the NASA Langley Research Center. The assessment process involves a combination of analysis, simulation, and tests and is comprehensive in that it addresses (i) closed-loop operation of the controller under test, (ii) real-rime dynamic detection of controller malfunctions, and (iii) the resulting effects on the aircraft relative to the stage of flight, flight conditions, and required operational performance. In support of the development of this process, closed-loop High-Intensity Radiated Fields (HIRF) effects experiments were performed on a fault tolerant flight control computer (FCC). This paper presents an overview of the problem of ensuring the integrity of critical control systems operating in harsh electromagnetic environments, and an approach for the assessment of these systems. A description of the closed-loop HIRF experiments, upset data obtained from the FCC during the experiments, and closed-loop effects on the simulated flight of the aircraft are also presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Belcastro, CM (reprint author), NASA, Langley Res Ctr, Mail Stop 130, Hampton, VA 23681 USA. NR 0 TC 6 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 353 EP 358 PG 6 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200077 ER PT S AU Elks, CR Johnson, BW Perrone, PG AF Elks, CR Johnson, BW Perrone, PG GP AMER AUTOMAT CONTROL COUNCIL TI System level error models for safety critical control systems. SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB The problem of verifying the functional integrity of control system in a range of operating conditions is a key issue in the design and development of safety critical systems. The integrity can be compromised by a variety of source, these include, Hardware faults, design errors, and Electromagnetic disturbances. In the past, the prime method for demonstrating the functional integrity of a control system in the presence of faults has been fault injection[6,7]. Most of fault injection methodologies are fraught with a host of limitations with respect to modeling the effects of EMI upsets. This paper presents a system level error model for a generic control computing platform. Errors are modeled from a high level system perspective without consideration for the actual physical failures, and the implementation details. This error model serves to classify error patterns which may occur in the information flow during EMI exposure. C1 NASA, Langley Res Ctr, Assessment Technol Branch, Hampton, VA 23665 USA. RP Elks, CR (reprint author), NASA, Langley Res Ctr, Assessment Technol Branch, Hampton, VA 23665 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 365 EP 369 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200079 ER PT S AU Belcastro, CM AF Belcastro, CM GP AMER AUTOMAT CONTROL COUNCIL TI Monitoring functional integrity in critical control computers subjected to electromagnetic disturbances SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Verifying the integrity of control computers operating in harsh electromagnetic environments is a key issue in the development, certification, and operation of control systems performing flight critical functions for future transport aircraft Harsh electromagnetic environments (EME) are caused by sources such as lightning, high-intensity radiated fields (HIRF) from radars and radio frequency (RF) transmitters, personal electronic devices carried onto the aircraft by passengers, electromagnetic interference and incompatibilities with onboard equipment, onboard or ground-based terrorists using RF weapons, and erroneous ground-based or airborne military activities. This paper considers the problem of applying analytical redundancy, distributed detection techniques, and decision fusion to monitoring the integrity of a fault tolerant flight control computer with redundant processors for red-time laboratory and in-flight applications. This work is in the initial phase and focuses on the formulation of the design problem. The analytical redundancy for each control command is based on the nominal control law calculation using linear parameter varying (LPV) modeling techniques. Malfunctions in the control law calculation of each processor are detected with statistical decision rules. The threshold of the decision rules is based on the residual between the measured control law calculation (that may result from computer malfunctions) from the control computer and the estimate of the correct command obtained from an LPV Kalman filter. Therefore, the decision rules are scheduled over the varying parameters. Malfunctions in each processor are detected by fusing the decisions from M control law calculation monitors. Malfunctions in the fault tolerant controller are detected by fusing the decisions from the monitors for N processors. Analysis of the performance of the distributed monitoring system is discussed. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Belcastro, CM (reprint author), NASA, Langley Res Ctr, Mail Stop 130, 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 374 EP 378 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200081 ER PT S AU Bayard, DS AF Bayard, DS GP AMER AUTOMAT CONTROL COUNCIL TI Exponential tracking error convergence bounds for overparametrized adaptive feedforward systems SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Many practical adaptive feedforward systems are overparametrized and for this reason will not satisfy persistent excitation.(PE) conditions. For these systems a weaker PE condition Is proposed under which it is shown that the tracking error (the error between the desired and estimated outputs) converges exponentially. Bounds are given on the exponential rate of convergence useful for systematic optimization and design purposes. Interestingly, it is also shown that some (but not all) of the robustness properties associated with full PE are retained under the weakened PE condition. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayard, DS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 604 EP 608 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200129 ER PT S AU Wilson, E Mah, RW Guerrero, MC Galvagni, AE Wallace, MA Winters, JL AF Wilson, E Mah, RW Guerrero, MC Galvagni, AE Wallace, MA Winters, JL GP AMER AUTOMAT CONTROL COUNCIL TI Imbalance identification and compensation for an airborne telescope SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Airborne telescopes are typically supported by spherical bearings to prevent angular motions of the aircraft from affecting telescope pointing accuracy. Mass balancing of the telescope about the center of rotation is necessary to minimize the motor torque requirements. A static-balancing procedure that uses peg-mounted and moving counterweights to make the telescope center of mass coincident with the center of rotation is presented. Force-transducer measurements of the imbalance torque were used to identify the mass imbalance. A least-squares-directed search algorithm was developed to optimize placement of peg-mounted and moving counterweights for coarse and fine balancing. When implemented on a similar to 100 kg laboratory prototype, the procedure achieved balancing to within a mass-moment error of 0.005 kg-m in less than 5 minutes. This is more accurate and up to 50 times faster than had been accomplished using previous methods. Two key developments for the achievement of these results were (1) imbalance identification using force transducers with both high accuracy near zero and high load capabilities and (2) an optimization method to place the discrete counterweights. C1 NASA, Ames Res Ctr, Lab Neuroengn Lab, Moffett Field, CA 94035 USA. RP Wilson, E (reprint author), NASA, Ames Res Ctr, Lab Neuroengn Lab, MS 269-1, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 856 EP 860 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200182 ER PT S AU Neat, GW Abramovici, A AF Neat, GW Abramovici, A GP AMER AUTOMAT CONTROL COUNCIL TI Control technology lessons learned: Case study using the Micro-Precision Interferometer testbed SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper presents a partial account of control lessons learned during the development of the Micro-Precision Interferometer (MPI) testbed. These lessons came about through the design, implementation and test of a specific testbed control system. However, the described lessons are not specific to the application. The topics range from global aspects like how to measure system performance to detailed compensator implementation issues. All of the insights presented would not have been reached without taking this hardware step. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Neat, GW (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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 879 EP 883 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200187 ER PT S AU Brown, GM Johnson, SA AF Brown, GM Johnson, SA GP AMER AUTOMAT CONTROL COUNCIL TI An overview of the fault protection design for the Attitude Control Subsystem of the Cassini spacecraft SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper describes Cassini's fault tolerance objectives, and how those objectives have influenced the design of its Attitude Control Subsystem (ACS). Particular emphasis is placed on the architecture of the software algorithms that are used to detect, locate, and recover from ACS faults, and the integration of these algorithms into the rest of the object-oriented ACS night software. The interactions of these ACS "fault protection" algorithms with Cassini's system-level fault protection algorithms is also described. We believe that the architecture of the ACS fault protection algorithms provides significant performance and operability improvements over the fault protection algorithms that have flown on previous interplanetary spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Brown, GM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 884 EP 898 PG 15 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200188 ER PT S AU Macala, GA AF Macala, GA GP AMER AUTOMAT CONTROL COUNCIL TI State-space fault monitor architecture and its application to the Cassini spacecraft SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB The Cassini spacecraft fault protection design includes fault monitors that use a state-space architecture to monitor the performance of spacecraft functions. This paper reports on the design of these monitors. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Macala, GA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 198-326, 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 899 EP 901 PG 3 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200189 ER PT S AU Lee, AY Brown, MJ AF Lee, AY Brown, MJ GP AMER AUTOMAT CONTROL COUNCIL TI A model-based thruster leakage monitor for the Cassini spacecraft SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB The Cassini spacecraft uses thrusters to maintain three-axis attitude control and to perform many other functions. If one of the thrusters leaks, the opposing thrusters will be fired excessively to maintain the commanded attitude. Obviously, the draining of hydrazine and the excessive firings of thrusters must be stopped quickly. A set of three model-based leakage detection monitors has been designed and implemented in the flight software to protect Cassini against the occurrence of this unlikely event. Test results indicate that this design can detect thruster leakage quickly and robustly. Once the leak is detected, the onboard fault protection logic will activate remedial actions which include the swapping of thruster branches. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, AY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 198-235, Pasadena, CA 91109 USA. NR 0 TC 4 Z9 5 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 902 EP 904 PG 3 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200190 ER PT S AU Gray, DL Brown, GM AF Gray, DL Brown, GM GP AMER AUTOMAT CONTROL COUNCIL TI Fault-tolerant guidance algorithms for Cassini's Saturn Orbit Insertion burn SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper describes a strategy that provides maximum assurance that Cassini's Saturn orbit insertion (SOI) will be successful. First, the criticality of the SOI to the mission is shown and how it reduces to an energy only correction. Then, autonomous on-board diagnostic and response algorithms are described that respond to any combination of problems that might be encountered during the burn. An accurate restart algorithm is implemented to complete the energy correction if at all possible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Gray, DL (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 905 EP 908 PG 4 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200191 ER PT S AU Johnson, SA AF Johnson, SA GP AMER AUTOMAT CONTROL COUNCIL TI Introduction to complex fault protection software testing SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper describes how fault protection software verification testing has been addressed for the Attitude and Articulation Control Subsystem on the Saturn-bound Cassini spacecraft. The verification included definition of failure injection capabilities to the test beds. The Cassini Fault Protection test program evolved using several test phases to complete separate goals which taken together encompassed all of the flight software complexities. This phased testing approach developed high confidence in the robustness and correctness of the FP flight software. Over 500 prelaunch tests of the flight software in a realistically modeled environment were used to ensure the design is robust to single faults. In the process we found that many double fault scenarios are handled by the Cassini Attitude and Articulation Control Subsystem fault protection software design. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, SA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 198-219, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 4 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 909 EP 911 PG 3 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200192 ER PT S AU Belcastro, CM AF Belcastro, CM GP AMER AUTOMAT CONTROL COUNCIL TI Parametric uncertainty modeling: An overview SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Robust control system analysis and design is based on an uncertainty description, called a linear fractional transformation (LFT), which separates the uncertain (or varying) part of the system from the nominal system. This paper provides an overview of the parametric uncertainty modeling process for nonlinear parameter-dependent systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Belcastro, CM (reprint author), NASA, Langley Res Ctr, Mail Stop 489, Hampton, VA 23681 USA. NR 0 TC 4 Z9 5 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 992 EP 996 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200211 ER PT S AU Morelli, EA AF Morelli, EA GP AMER AUTOMAT CONTROL COUNCIL TI Global nonlinear parametric modeling with application to F-16 aerodynamics SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB A global nonlinear parametric modeling technique is described and demonstrated. The technique uses multivariate orthogonal modeling functions generated from the data to determine nonlinear model structure, then expands each retained modeling function into an ordinary multivariate polynomial. The final model form is a finite multivariate power series expansion for the dependent variable in terms of the independent variables. Partial derivatives of the identified models can be used to assemble globally valid linear parameter varying models. The technique is demonstrated by identifying global nonlinear parametric models for nondimensional aerodynamic force and moment coefficients from a subsonic wind tunnel database for the F-16 fighter aircraft. Results show less than 10% difference between wind tunnel aerodynamic data and the nonlinear parameterized model for a simulated doublet maneuver at moderate angle of attack. Analysis indicated that the global nonlinear parametric models adequately captured the multivariate nonlinear aerodynamic functional dependence. C1 NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23665 USA. RP Morelli, EA (reprint author), NASA, Langley Res Ctr, Dynam & Control Branch, Hampton, VA 23665 USA. NR 0 TC 19 Z9 20 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 997 EP 1001 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200212 ER PT S AU Belcastro, CM Chang, BC AF Belcastro, CM Chang, BC GP AMER AUTOMAT CONTROL COUNCIL TI LFT formulation for multivariate polynomial problems SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Robust control system analysis and design is based on an uncertainty description, called a linear fractional transformation (LFT), which separates the uncertain (or varying) part of the system from the nominal system. Low-order LFT models are difficult to form for nonlinear parameter-dependent systems. This paper presents a numerical computational method that can be used to construct low-order LFT models for multivariate polynomial and rational problems based on simple matrix computations. This LFT modeling method makes current robust and linear parameter varying (LPV) control analysis and design methods accessible to a broad class of difficult practical problems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Belcastro, CM (reprint author), NASA, Langley Res Ctr, Mail Stop 161, Hampton, VA 23681 USA. NR 0 TC 5 Z9 6 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 1002 EP 1007 PG 6 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200213 ER PT S AU Lim, KB Giesy, DP AF Lim, KB Giesy, DP GP AMER AUTOMAT CONTROL COUNCIL TI Computation of LFT uncertainty bounds with repeated parametric uncertainties SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB A new methodology in which linear fractional transformation uncertainty bounds are directly constructed for use in robust control design and analysis is proposed. Existence conditions for model validating solutions with or without repeated scaler uncertainty are given. The approach is based on minimax formulation to deal with multiple non-repeated structured uncertainty components subject to fixed levels of repeated scalar uncertainties. Input directional dependence and variations with different experiments are addressed by maximizing uncertainty levels over multiple experimental data sets. Preliminary results show that reasonable uncertainty bounds on structured non-repeated uncertainties can be identified directly from measurement data by assuming reasonable levels of repeated scalar uncertainties. C1 NASA, Langley Res Ctr, Guidance & Control Branch, Flight Dynam & Control Div, Hampton, VA 23681 USA. RP Lim, KB (reprint author), NASA, Langley Res Ctr, Guidance & Control Branch, Flight Dynam & Control Div, MS 161, Hampton, VA 23681 USA. NR 0 TC 2 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 1018 EP 1022 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200216 ER PT S AU Grogan, RL Laskin, RA AF Grogan, RL Laskin, RA GP AMER AUTOMAT CONTROL COUNCIL TI On multidisciplinary modeling of the space interferometry mission SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB By measuring the positions and motions of stars very precisely, the Space Interferometry Mission (SIM) will produce a wealth of new astronomical data and serve as a technology pathfinder for future astrophysics missions providing a leap forward in space based astronomy beyond the Hubble Space Telescope. SIM wilt present unprecedented challenges in the measurement and control of distributed optical surfaces mounted on precision space structures, hence driving the technological state-of-the-art in the areas of alignment and stabilization of optical-mechanical systems, deployable structures, vibration isolation and suppression, laser metrology, and the integration and autonomous operation of complex systems. The precise tolerance required by the SIM instrument facilitates the investigation of many design options, trades, and methods for minimizing interaction between the actively controlled optics and the structure. This paper provides an overview of the multidisciplinary integrated modeling methodology for SIM that encompasses the optics, structures, dynamics, and control disciplines within a common software environment. Such integrated models are used at the Jet Propulsion Laboratory for system requirements trade studies, performance analysis and predictions, and control law design for the mission. The modeling methodology is rooted in a closely tied validation program which is necessary to alleviate the paradox of modeling a spacecraft that does not yet exist. The highest fidelity integrated SIM model to date, examples of utility, and incorporation into the overall instrument design are highlighted. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grogan, RL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 1558 EP 1562 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200332 ER PT S AU Neat, GW Abramovici, A Goullioud, R Korechoff, RP Calvet, RJ Joshi, SS AF Neat, GW Abramovici, A Goullioud, R Korechoff, RP Calvet, RJ Joshi, SS GP AMER AUTOMAT CONTROL COUNCIL TI Overview of the MicroPrecision interferometer testbed SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper gives an overview the Micro-Precision Interferometer (MPI) testbed and its major achievements to date related to mitigating risk for future spaceborne optical interferometer missions. The MPI testbed is a ground-based hardware model of a future spaceborne interferometer. The three primary objectives of the testbed are to: (1) demonstrate the 10 nm positional stability requirement in the ambient lab disturbance environment, (2) predict whether the 10 nm positional stability requirement can be achieved in the anticipated on-orbit disturbance environment, and (3) validate integrated modeling tools that will ultimately be used to design the actual space missions. This paper presents results which represent the latest advancements made on the testbed in the first two areas. Encouraging results from this testbed confirm that MPI provides an essential link between the extensive ongoing ground-based interferometer technology development activities and the technology needs of future spaceborne optical interferometers. Due to space limitations, all citations can be found in the bibliography of reference [1], which gives an expanded overview of MPI activities. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Neat, GW (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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 1563 EP 1568 PG 6 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200333 ER PT S AU Johnson, D Brown, GV Inman, DJ AF Johnson, D Brown, GV Inman, DJ GP AMER AUTOMAT CONTROL COUNCIL TI Adaptive variable bias magnetic bearing control SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB Most magnetic bearing control schemes use a bias current with a superimposed control current to linearize the relationship between the control current and the force it delivers. With the existence of the bias current, even in no load conditions, there is always some power consumption. In aerospace applications, power consumption becomes an important concern. In response to this concern, an alternative magnetic bearing control method, called Adaptive Variable Bias Control (AVBC), has been developed and its performance examined. The AVBC operates primarily as a proportional-derivative controller with a relatively slow, bias current dependent, time-varying gain. The AVBC is shown to reduce electrical power loss, be nominally stable, and provide control performance similar to conventional bias control. Analytical, computer simulation, and experimental results are presented in this paper. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Johnson, D (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 9 Z9 9 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 2217 EP 2223 PG 7 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200472 ER PT S AU Lorenzo, CF Holmes, MS AF Lorenzo, CF Holmes, MS GP AMER AUTOMAT CONTROL COUNCIL TI Nonlinear control of a reusable rocket engine for life extension SO PROCEEDINGS OF THE 1998 AMERICAN CONTROL CONFERENCE, VOLS 1-6 SE PROCEEDINGS OF THE AMERICAN CONTROL CONFERENCE LA English DT Proceedings Paper CT American Control Conference CY JUN 24-26, 1998 CL PHILADELPHIA, PA SP Amer Automat Control Council, AIAA, AIChE, ASCE, IEEE, ISA, SCS AB This paper presents the conceptual development of a life-extending control system where the objective is to achieve high performance and structural durability of the plant. A life-extending controller is designed for a reusable rocket engine via damage mitigation in both the fuel (H-2) and oxidizer(O-2) turbines while achieving high performance for transient responses of the combustion chamber pressure and the O-2/H-2 mixture ratio. The design procedure makes use of a combination of linear and nonlinear controller synthesis techniques and also allows adaptation of the life-extending controller module to augment a conventional performance controller of the rocket engine. The nonlinear aspect of the design is achieved using non-linear parameter optimization of a prescribed control structure. Fatigue damage in fuel and oxidizer turbine blades is primarily caused by stress cycling during start-up, shutdown, and transient operations of a rocket engine. Fatigue damage in the turbine blades is one of the most serious causes for engine failure. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Lorenzo, CF (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 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 0743-1619 BN 0-7803-4530-4 J9 P AMER CONTR CONF PY 1998 BP 2922 EP 2926 PG 5 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications SC Automation & Control Systems; Computer Science GA BL45T UT WOS:000075568200627 ER PT B AU Ewert, MK Agrella, M Frahm, J Bergeron, DJ Berchowitz, D AF Ewert, MK Agrella, M Frahm, J Bergeron, DJ Berchowitz, D BE CampbellHowe, R Cortez, T WilkinsCrowder, B TI Experimental evaluation of a solar PV refrigerator with thermoelectric, Stirling and vapor compression heat pumps SO PROCEEDINGS OF THE 1998 AMERICAN SOLAR ENERGY SOCIETY ANNUAL CONFERENCE LA English DT Proceedings Paper CT Annual Conference of the American-Solar-Energy-Society CY JUN 14-17, 1998 CL ALBUQUERQUE, NM SP Amer Solar Energy Soc, US DOE, Org Amer States, Sandi Natl Labs, Univ New Mexico, NationsBank, New Mexico Land Off, US DOE, Albuquerque Operat Off, Public Serv Co New Mexico, New Mexico Energy Off AB Solar photovoltaic (PV) refrigeration systems that use batteries have existed for several decades but have only been used in limited applications. Recent technology developments and experimentation in the field are refining the "solar refrigerator." Coupled with the decreasing cost of PV, this is expected to lead to more wide-spread acceptance and use. Keys to the success of the solar refrigerator are a thermally efficient cabinet, thermal storage, and a high-efficiency heat pump. These elements, which are also important for aerospace refrigerators, were combined in a successful demonstration of solar refrigerator technology at the Johnson Space Center. Three heat pump, or "cooler," technologies (thermoelectric, Stirling, and vapor compression) were experimentally evaluated in the same vacuum insulated cabinet. Individual heat pump performance was quantified, and the entire solar refrigerator system was evaluated by defining a system solar COP (coefficient of performance). C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Ewert, MK (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1,Mail Code EC2, Houston, TX 77058 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN SOLAR ENERGY SOCIETY INC PI BOULDER PA 2400 CENTRAL AVE, SUITE G-1, BOULDER, CO 80301 USA BN 0-89553-170-4 PY 1998 BP 59 EP 65 PG 7 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA BP59C UT WOS:000085592900009 ER PT S AU Satorius, E AF Satorius, E GP IEEE TI Co-channel FM voice separation via cross coupled phase locked loops SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-6 SE International Conference on Acoustics Speech and Signal Processing (ICASSP) LA English DT Proceedings Paper CT IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 98) CY MAY 12-15, 1998 CL SEATTLE, WA SP IEEE Signal Proc Soc AB This paper presents the results of simulation experiments that successfully demonstrate FM co-channel voice separation via cross coupled phase locked loops (CCPLL). Unlike previous CCPLL studies which are typically restricted to the situation where the FR? modulation waveforms are steady state sinusoidal, triangular, etc., we have empirically determined CCFLL loop parameters that provide for stable separation of co-channel FM signals with comparable bandwidth (100% spectral overlap) and comparable mod indices. The resulting CCPLL parameters differ somewhat from existing CCPLL design rules; however, the differences can yield a significant improvement in CCPLL performance. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Satorius, E (reprint author), CALTECH, Jet Prop Lab, Mail Stop 238-420, 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 1520-6149 BN 0-7803-4428-6 J9 INT CONF ACOUST SPEE PY 1998 BP 3293 EP 3295 PG 3 WC Acoustics; Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Acoustics; Computer Science; Engineering; Telecommunications GA BL16B UT WOS:000074520700824 ER PT S AU Hamkins, J AF Hamkins, J GP IEEE TI A joint Viterbi algorithm to separate cochannel FM signals SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING, VOLS 1-6 SE International Conference on Acoustics Speech and Signal Processing (ICASSP) LA English DT Proceedings Paper CT IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP 98) CY MAY 12-15, 1998 CL SEATTLE, WA SP IEEE Signal Proc Soc AB This paper presents a method for separating cochannel FM signals. We show that the Viterbi algorithm, traditionally limited to estimation of digital sequences, can jointly track analog FM signals by separately quantizing the derivatives of their instantaneous frequencies. We employ per-survivor processing in the trellis to estimate unknown channel effects. The approach works well when the signal to interference ratio (SIR) is less than or equal to zero, in contrast to conventional interference suppression algorithms that degrade as SIR approaches zero and fail catastrophically when SIR < 0. Comparisons of mean squared error (MSE) between the estimates and the true signals are given for varying SIR, SNR, Doppler offsets, and frequency deviations. The same approach can also be used for any other continuous phase modulation scheme, such as continuous-phase frequency-shift keying (CPFSK). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 238-420, 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 1520-6149 BN 0-7803-4428-6 J9 INT CONF ACOUST SPEE PY 1998 BP 3297 EP 3300 PG 4 WC Acoustics; Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Acoustics; Computer Science; Engineering; Telecommunications GA BL16B UT WOS:000074520700825 ER PT S AU Dick, GJ Greenhall, CA AF Dick, GJ Greenhall, CA GP IEEE IEEE TI LO limited frequency stability for passive atomic frequency standards using "square wave" frequency modulation SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB Atomic frequency standards using square-wave frequency modulation effectively interrogate the atomic line by switching back and forth between two frequencies with equal atomic absorption values. For a symmetric absorption line, the slope of the responses will also be equal. In the quasi-static limit this would seem to be an ideal interrogation process - the sign reversal of frequency slope can be removed by detection electronics to give an essentially unvarying and constant sensitivity to L.O. frequency variations. Such an interrogation would seem to eliminate L.O. aliasing and so relieve stringent requirements on local oscillator phase noise. However, sign changes in the interrogation and detection processes mean that the sensitivity is actually zero at some point in the cycle. We derive consequences of this fact for white phase and flicker phase noise models by an explicitly time-dependent analysis in terms of the sensitivity function g(t). We find that an optimal strategy exists for white phase L.O. noise for which g(t) takes the form of a sequence of parabolic arches, and which gives a small (x96/ pi(4)) improvement over simple sine-wave demodulation. We also find limiting forms that could in principle eliminate L.O. aliasing for flicker-phase noise. However, in practice the improvement shows only a logarithmic dependence on available response time and bandwidth. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dick, GJ (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 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 99 EP 103 DI 10.1109/FREQ.1998.717888 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400021 ER PT S AU Maleki, L Prestage, J Nordtvedt, K Armstrong, J Anderson, J Vessot, R Damour, T Soffel, M AF Maleki, L Prestage, J Nordtvedt, K Armstrong, J Anderson, J Vessot, R Damour, T Soffel, M GP IEEE IEEE TI Relativity at four solar radii SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB In the strongly time dilated spacetime curvature at four solar radii, time runs slower than on earth by about one half microsecond per second. Three atomic clocks based on hyperfine transitions of Hg+ (Z=80), Cd+ (Z=48), and Yb+(Z=70) are different in their electromagnetic composition (given by the Casimir hyperfine factor) and will be inter-compared during a solar flyby to determine whether clocks of different physical makeup will measure the same time interval in the strong spacetime curvature near the sun. The atomic clock hardware for the Space Time mission is a modification of the linear ion trap frequency standard (LITS) currently being deployed in the Deep Space Network stations worldwide. A laboratory prototype has shown ultra-stable operation in a package far smaller than other clock technologies and represents the state of the art for atomic clocks. The instrument for this mission is composed of three ion trap clocks in a package where much of the hardware is common to all of the clocks. Because some of the clock systematic frequency perturbations will be common to all three clocks and will have a characteristic signature that can be identified and removed from the difference of the clock frequencies, relative stability's to 10(-16) in the intercomparison can be reached, making a 10(-10) test of the Equivalence Principle. The local oscillator will simultaneously interrogate each of the three clock transitions thereby removing LO noise in the inter-comparison, greatly improving short term clock noise so that 10(-16) resolution in the difference in clock rates can be obtained within the 15 hour close encounter. Because ion trap based clocks are relatively immune to temperature and magnetic field changes, a simple, robust electronics package is sufficient for ultra-stable operation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Maleki, L (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 329 EP 335 DI 10.1109/FREQ.1998.717924 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400057 ER PT S AU Sandor, M Cuddihy, E Agarwal, S AF Sandor, M Cuddihy, E Agarwal, S GP IEEE IEEE TI A study of plastic encapsulated microcircuits (PEMs) in JPL space hardware SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB The qualification and use of COTS parts including parts assembled with plastic packages are currently under study and evaluation by the Jet Propulsion Laboratory. Work is underway to build a database for PEMs that will aide in determining acceptance of generic part families by vendor and package. Data is being gathered on PEMs which includes radiation tolerance, outgassing, moisture absorption/desorption, acoustic microscopy, glass transition temperature, and dye penetration. The results will then be used to make quality, reliability, and risk assessments that in turn would provide projects an avenue to use COTS parts for various missions. The end objective is to establish and define criteria that will allow users of PEMs to determine their risk when plastic parts are used in lieu of traditional ceramic parts. The data and findings will be presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sandor, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 303-230, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 405 EP 421 DI 10.1109/FREQ.1998.717934 PG 17 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400067 ER PT S AU Dick, GJ Wang, RT Tjoelker, RL AF Dick, GJ Wang, RT Tjoelker, RL GP IEEE IEEE TI Cryo-cooled sapphire oscillator with ultra-high stability SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB We present test results and design details for the first short-term frequency standard to achieve ultra-high stability without the use of liquid helium. With refrigeration provided by a commercial cryocooler, the Compensated Sapphire Oscillator (10K CSO) makes available the superior short-term stability and phase noise performance of cryogenic oscillators without periodic interruptions for cryogen replacement. Technical features of the 10K CSO include use of a a-stage cryocooler with vibration isolation by helium gas at atmospheric pressure, and a new sapphire/ruby resonator design giving compensated operation at 8-10K with Q = 1 - 2 x 10(9). Stability of the first unit shows an Allan Deviation of sigma(y) less than or equal to 2.5 x 10(-15) for measuring times of 200 seconds less than or equal to tau less than or equal to 600 Seconds. We also present results showing the capability of the 10K CSO to eliminate local oscillator degradation for atomic frequency standards. Configured as L.O. for the LITS-7 trapped mercury ion frequency standard, the CSO/LITS combination demonstrated a limiting performance of 3.0 x 10(-14)/tau(1/2), the lowest value measured to date for a,passive atomic frequency standard, and virtually identical to the value calculated from photon statistics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dick, GJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 19 Z9 19 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 528 EP 533 DI 10.1109/FREQ.1998.717949 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400082 ER PT S AU Yao, XS Maleki, L Davis, L AF Yao, XS Maleki, L Davis, L GP IEEE IEEE TI Coupled opto-electronic oscillators SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB We present experimental results of coupled optoelectronic oscillators (COEO) constructed with a semiconductor optical amplifier based ring laser and a semiconductor colliding pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices. we obtained optical pulses as short as 6.2 picoseconds and RF signals as high, in frequency, as 18 GHz with a spectral purity comparable with a HP8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yao, XS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 540 EP 544 DI 10.1109/FREQ.1998.717951 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400084 ER PT S AU Yao, XS Maleki, L Ji, Y Lutes, G Tu, MR AF Yao, XS Maleki, L Ji, Y Lutes, G Tu, MR GP IEEE IEEE TI Dual-loop opto-electronic oscillator SO PROCEEDINGS OF THE 1998 IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM SE PROCEEDINGS OF THE IEEE INTERNATIONAL FREQUENCY CONTROL SYMPOSIUM LA English DT Proceedings Paper CT IEEE International Frequency Control Symposium CY MAY 27-29, 1998 CL PASADENA, CA SP IEEE, Ultrasonics Ferroelectr & Frequency Control Soc AB We describe and demonstrate a multi-loop technique for single mode selection in an optoelectronic oscillator. We present experimental results of a dual loop OEO free running at 10 GHz that has the lowest phase noise (-140 dBc/Hz at 10 kHz from carrier) of free running room temperature oscillator to date. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yao, XS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 8 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1075-6787 BN 0-7803-4373-5 J9 P IEEE INT FREQ CONT PY 1998 BP 545 EP 549 DI 10.1109/FREQ.1998.717952 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA BL72D UT WOS:000076440400085 ER PT S AU Drake, SA AF Drake, SA BE North, P Schnell, A Ziznovsky, J TI High-energy phenomena in magnetic CP stars as revealed by their X-ray and radio emission SO PROCEEDINGS OF THE 26TH MEETING AND WORKSHOP OF THE EUROPEAN WORKING GROUP ON CP STARS SE CONTRIBUTIONS OF THE ASTRONOMICAL OBSERVATORY SKALNATE PLESO-B SAMPLE LA English DT Proceedings Paper CT 26th Meeting and Workshop of the European-Working-Group-on-CP-Stars CY OCT 27-29, 1997 CL VIENNA, AUSTRIA SP European Working Grp CP Stars, Slovak Astronom Soc DE stars, chemically peculiar; radio continuum, stars; X-rays, stars AB Before 1985, attempts to detect radio or x-ray emission from magnetic CP (MCP) stars were either fruitless or ambiguous. However, more successful results have been obtained in the last dozen years: (i) Radio emission has now been detected from similar-to 35 MCP stars of the Helium-peculiar and Silicon-strong subclasses, with a functional dependence of radio luminosity LR proportional-to (TeffHsProt-0.6)-H-7-P-1.2, where T-eff is the effective temperature, H-s is the surface magnetic field strength, and P-rot is the rotational period; rotational modulation of the radio emission has also been observed for several MCP stars. All of this evidence suggests that it is the MCP stars themselves, not close companions, that are responsible for the radio emission; (ii) The x-ray emission properties of MCP stars are however still poorly characterized: although a moderate number (similar-to 18) have by now been associated with x-ray sources, the lack of a clear correlation of this x-ray emission with other stellar parameters has made it difficult to rule out the close companion hypothesis. C1 NASA, Goddard Space Flight Ctr, HEASARC, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, HEASARC, Greenbelt, MD 20771 USA. EM drake@heavx.gsfc.nasa.gov NR 31 TC 7 Z9 7 U1 0 U2 0 PU SLOVAK ACADEMY SCIENCES ASTRONOMICAL INSTITUTE PI TATRANSKA LOMNICA PA 059 60 TATRANSKA LOMNICA, SLOVAKIA SN 1335-1842 J9 CONTR AST O PY 1998 VL 27 IS 3 BP 382 EP 389 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL19E UT WOS:000074636400047 ER PT S AU Shen, YX Homaifar, A Bikdash, M Chen, D AF Shen, YX Homaifar, A Bikdash, M Chen, D GP IEEE IEEE TI Genetic algorithms- and fuzzy-based vibration control of plate using PZT actuators SO PROCEEDINGS OF THE 37TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 SE IEEE CONFERENCE ON DECISION AND CONTROL - PROCEEDINGS LA English DT Proceedings Paper CT 37th IEEE Conference on Decision and Control CY DEC 16-18, 1998 CL TAMPA, FL SP IEEE Control Syst Soc, Soc Ind & Appl Math, Inst Operat Res & Management Sci DE PZT patches; modeling; active vibration control; rate-feedback; fuzzy logic; genetic algorithms AB The paper presents a control system testbed which is used for active vibration control. Software simulation and real-time experiments are realized at the same time using different control methodologies through the MATLAB and dSPACE environments. Localized control with hybrid-fuzzy PD controller, Genetic Algorithms-designed PD controller and rate-feedback controller are shown to attenuate vibration at resonance frequencies. The results confirm that these three kinds of control methods are reliable in the active damping of the vibration. C1 N Carolina Agr & Technol State Univ, Dept Elect Engn, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. RP Shen, YX (reprint author), N Carolina Agr & Technol State Univ, Dept Elect Engn, NASA, Ctr Aerosp Res, Greensboro, NC 27411 USA. NR 4 TC 9 Z9 9 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0191-2216 BN 0-7803-4394-8 J9 IEEE DECIS CONTR P PY 1998 BP 2930 EP 2933 PG 4 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Operations Research & Management Science; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Operations Research & Management Science; Mathematics GA BM76E UT WOS:000079708900576 ER PT S AU Kreinovich, V Nguyen, HT Starks, SA Yam, Y AF Kreinovich, V Nguyen, HT Starks, SA Yam, Y GP IEEE IEEE TI Decision making based on satellite images: Optimal fuzzy clustering approach SO PROCEEDINGS OF THE 37TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 SE IEEE CONFERENCE ON DECISION AND CONTROL - PROCEEDINGS LA English DT Proceedings Paper CT 37th IEEE Conference on Decision and Control CY DEC 16-18, 1998 CL TAMPA, FL SP IEEE Control Syst Soc, Soc Ind & Appl Math, Inst Operat Res & Management Sci AB In many real-life decision-making situations, in particular, in processing satellite images, we have an enormous amount of information to process. To speed up the information processing, it is reasonable to first classify the situations into a few meaningful classes (clusters), find the best decision for each class, and then, for each new situation, to apply the decision which is the best for the corresponding class. One of the most efficient clustering methodologies is fuzzy clustering, which is based on the use of fuzzy logic. Usually, heuristic clustering are used, i.e., methods which are selected based on their empirical efficiency rather than on their proven optimality. Because of the importance of the corresponding decision making situations, it is therefore desirable to theoretically analyze these empirical choices. In this paper, we formulate the problem of choosing the optimal fuzzy clustering as a precise mathematical problem, and we show that in the simplest cases, the empirically best fuzzy clustering methods are indeed optimal. C1 Univ Texas, NASA, Pan Amer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. RP Kreinovich, V (reprint author), Univ Texas, NASA, Pan Amer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. RI Yam, Yeung/C-9493-2011 OI Yam, Yeung/0000-0001-9950-5794 NR 24 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0191-2216 BN 0-7803-4394-8 J9 IEEE DECIS CONTR P PY 1998 BP 4246 EP 4251 PG 6 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Operations Research & Management Science; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Operations Research & Management Science; Mathematics GA BM76E UT WOS:000079708900821 ER PT S AU Bayard, DS AF Bayard, DS GP IEEE IEEE TI Fast observers for spacecraft pointing control SO PROCEEDINGS OF THE 37TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-4 SE IEEE CONFERENCE ON DECISION AND CONTROL - PROCEEDINGS LA English DT Proceedings Paper CT 37th IEEE Conference on Decision and Control CY DEC 16-18, 1998 CL TAMPA, FL SP IEEE Control Syst Soc, Soc Ind & Appl Math, Inst Operat Res & Management Sci AB This paper is concerned with designing fast stochastic observers for spacecraft pointing control. The motivation is to try to circumvent the long settling times associated with the optimal Kalman filter, which are often on the order of several hundred seconds in many typical spacecraft applications. For this purpose, the Karush-Kuhn-Tucker (KKT) necessary conditions are used to solve for an optimal constrained stochastic observer which minimizes the variance of the attitude estimation error subject to the constraint that its poles lie to the left of a specified vertical line in the Laplace s-plane. A globally optimal analytical solution is found for the typical case where the attitude estimator is comprised of three decoupled single-axis observers, each of second-order form. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bayard, DS (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 0191-2216 BN 0-7803-4394-8 J9 IEEE DECIS CONTR P PY 1998 BP 4702 EP 4707 PG 6 WC Automation & Control Systems; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic; Operations Research & Management Science; Mathematics, Applied SC Automation & Control Systems; Computer Science; Engineering; Operations Research & Management Science; Mathematics GA BM76E UT WOS:000079708900927 ER PT B AU Lau, KM AF Lau, KM BE Chang, CP Chan, JCL Wang, JT TI Monsoon Southern Oscillation coupling: A preliminary GCM study SO PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON EAST ASIA AND WESTERN PACIFIC METEOROLOGY AND CLIMATE LA English DT Proceedings Paper CT 3rd International Conference on East Asia and Western Pacific Meteorology and Climate CY MAY 16-18, 1996 CL CHUNGLI, TAIWAN AB The relative impact of land evaporation-atmosphere coupling and SST forcing on the Asian monsoon-Southern Oscillation system is examined from a series of GCM experiments. It is found that the interannual variability of the coupled Asian monsoon-Southern Oscillation (AM-SO) system is controlled mainly by anomalous SST forcing. Consistent with previous studies, strong (weak) Asian monsoon is associated with the cold (warm) phase of ENSO. SST anomalies allow anomalies in the AM to be communicated globally, while seasonally fixed SST limits the influence of the anomalous RM to the northern hemisphere and Eurasia. We also found that the interannual variability of the AM-SO system that can be attributed to land-atmosphere coupling is relatively small. Strong asymmetries with respect to the annual cycle are found in the mean behavior of the AM-SO system with the SO responding rapidly to the annual cycle forcing in late boreal winter/early spring, while the AM signal remains almost unchanged. During late boreal spring to early summer, the AM activity picks up suddenly, while the SO remains relatively unchanged. The above behavior suggests a "capacitor" effect with a slow build-up and a vapid discharge of energy via the SO and the AM during different seasons. This behavior appears to be inherent in the atmosphere-land coupled system forced by climatological SST. While the effect of land-evaporation interaction appears to be smalt an the large scale coupled AM-SO system, ifs regional influence is significant Over East Asia, land surface evaporation-atmosphere interaction is responsible for the excitation of a see-saw oscillation in precipitation over land and the adjacent ocean. The polarity of this oscillation appears to be chaotic, being dependent on the large scale circulation forced by SST anomalies and the seasonal cycle, with the transition being phase-locked to the late spring/early summer period. C1 NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3047-8 PY 1998 BP 50 EP 59 PG 10 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA BM06A UT WOS:000077489700008 ER PT B AU Tao, WK Chen, C Lau, KM Lai, G Wang, Y AF Tao, WK Chen, C Lau, KM Lai, G Wang, Y BE Chang, CP Chan, JCL Wang, JT TI Modeling tropical convective systems SO PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON EAST ASIA AND WESTERN PACIFIC METEOROLOGY AND CLIMATE LA English DT Proceedings Paper CT 3rd International Conference on East Asia and Western Pacific Meteorology and Climate CY MAY 16-18, 1996 CL CHUNGLI, TAIWAN C1 NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tao, WK (reprint author), NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 0 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE BN 981-02-3047-8 PY 1998 BP 363 EP 363 PG 1 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA BM06A UT WOS:000077489700049 ER PT S AU Wu, SY Liu, AK Tseng, WY AF Wu, SY Liu, AK Tseng, WY BE Chung, JS Olagnon, M Kim, CH Koterayama, W TI Wavelet analysis of satellite imagery on coastal oil spills SO PROCEEDINGS OF THE EIGHTH INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 3 SE International Offshore and Polar Engineering Conference Proceedings LA English DT Proceedings Paper CT 8th International Offshore and Polar Engineering Conference (ISOPE-98) CY MAY 24-29, 1998 CL MONTREAL, CANADA SP Int Soc Offshore & Polar Engineers DE wavelet analysis; oil spill; SAR; AVHRR; RADARSAT AB With the aid of satellite remote sensing imagery, it is now possible to monitor the seawater with adequate temporal and spatial coverage for marine pollution and biological productivity. In this paper, we present case studies on two major coastal oil spills, which have been captured by the remote sensing imagery. The detection and tracking of the oil slicks are achieved by means of two-dimensional Gaussian-based wavelet analysis. This work demonstrates that this technique is a useful and promising tool for monitoring of coastal waters. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wu, SY (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU INTERNATIONAL SOCIETY OFFSHORE& POLAR ENGINEERS PI CUPERTINO PA PO BOX 189, CUPERTINO, CA 95015-0189 USA SN 1098-6189 BN 1-880653-37-0 J9 INT OFFSHORE POLAR E PY 1998 BP 25 EP 29 PG 3 WC Engineering, Marine; Engineering, Petroleum; Engineering, Geological; Mechanics; Remote Sensing SC Engineering; Mechanics; Remote Sensing GA BL50Z UT WOS:000075723700005 ER PT S AU Liu, AK Zhao, YH AF Liu, AK Zhao, YH BE Chung, JS Olagnon, M Kim, CH Koterayama, W TI Sea ice motion from wavelet analysis of satellite data SO PROCEEDINGS OF THE EIGHTH INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 3 SE International Offshore and Polar Engineering Conference Proceedings LA English DT Proceedings Paper CT 8th International Offshore and Polar Engineering Conference (ISOPE-98) CY MAY 24-29, 1998 CL MONTREAL, CANADA SP Int Soc Offshore & Polar Engineers DE sea ice drift; wavelet transform; remote sensing AB Wavelet analysis of microwave satellite data is used to obtain daily sea ice drift information for both the northern and southern polar regions. This technique provides improved spatial coverage over the existing array of Arctic Ocean buoys and better temporal resolution currently available with other satellite sensors. Examples of derived ice-drift maps for the Arctic illustrate large-scale circulation reversals over a period of a few days. Comparisons of satellite-derived ice motion with ice displacements derived from buoys give good quantitative agreement. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Liu, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU INTERNATIONAL SOCIETY OFFSHORE& POLAR ENGINEERS PI CUPERTINO PA PO BOX 189, CUPERTINO, CA 95015-0189 USA SN 1098-6189 BN 1-880653-37-0 J9 INT OFFSHORE POLAR E PY 1998 BP 30 EP 35 PG 2 WC Engineering, Marine; Engineering, Petroleum; Engineering, Geological; Mechanics; Remote Sensing SC Engineering; Mechanics; Remote Sensing GA BL50Z UT WOS:000075723700006 ER PT S AU Castell, K Hernandez-Pellerano, A AF Castell, K Hernandez-Pellerano, A BE Harris, RA TI An adaptable power system with software control algorithm SO PROCEEDINGS OF THE FIFTH EUROPEAN SPACE POWER CONFERENCE (ESPC), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 5th European Space Power Conference (ESPC) CY SEP 21-25, 1998 CL TARRAGONA, SPAIN SP European Space Agcy, Diputacio Tarragona, City Tarragona, Caixa Tarragona DE power system; spacecraft power; software control AB A low cost, flexible and modular spacecraft power system design was developed in response to NASA's call for an architecture that could accommodate multiple missions in the small to medium load range. This design is currently being implemented on three spacecraft, with orbits that include circular, polar elliptical and near a libration point. The design consists of table-driven, adjustable software and modular hardware that can be scaled up or down, without additional cost, to suit missions in the 200 to 600 Watt orbital average load range. Mission unique adaptations are accomplished in software and firmware. In designing this advanced, adaptable power system, the major goals were reduction in mass, volume and cost. This power system design represents reductions in mass of 78%, volume of 86% and cost of 79% from previous comparable systems. The efforts to miniaturize the electronics without sacrificing performance has created streamlined power electronics with control functions residing in the system microprocessor. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Castell, K (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-664-3 J9 ESA SP PUBL PY 1998 VL 416 BP 251 EP 256 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA BL96W UT WOS:000077307300039 ER PT B AU Sawyer, W Lucchesi, R Lyster, PM Takacs, LL Larson, J Molod, A Nebuda, S Pabon-Ortiz, C AF Sawyer, W Lucchesi, R Lyster, PM Takacs, LL Larson, J Molod, A Nebuda, S Pabon-Ortiz, C BE Tentner, A TI Parallelization aspects of an atmospheric general circulation model for data assimilation SO PROCEEDINGS OF THE HIGH-PERFORMANCE COMPUTING (HPC'98) LA English DT Proceedings Paper CT 6th High Performance Computing Symposium on Grand Challenges in Computer Simulation at the 1998 Advanced Simulation Technologies Conference CY APR 05-09, 1998 CL BOSTON, MA SP Soc Comp Simulat Int DE parallel processing; data assimilation; general circulation model AB The National Aeronautics and Space Administration (NASA) Data Assimilation Office (DAO) at the Goddard Space Flight Center is porting its data assimilation system (DAS) to massively parallel computers. The parallel implementation of GEOS DAS will be used in the DAO's production work, which includes data reanalysis and operational support for flight missions, and it is expected to play an important role in the Mission to Planet Earth (MTPE) system. The parallelization of GEOS DAS is also one of the High Performance Computing and Communications Initiative (HPCC) Grand Challenge projects. A key component of GEOS DAS is the gridpoint-based atmospheric general circulation model or AGCM which currently takes roughly half of the overall execution time. Proposed increases in the model resolution and modifications of the science require corresponding increases in performance to maintain the current throughput. To meet this challenge DAO researchers have rewritten an existing AGCM using the Message Passing Interface (MPI) for use in GEOS DAS' stratospheric modeling and have written new software to support parallel I/O and grid transformations. In this paper, the parallelization of the GEOS AGCM will be described and the key performance obstacles treated. We will present the most current benchmarks arising from the HPCC Grand Challenge project. Finally, we will discuss future work on the GEOS DAS system. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Sawyer, W (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU SOC COMPUTER SIMULATION PI SAN DIEGO PA PO BOX 17900, SAN DIEGO, CA 92177 USA BN 1-56555-145-1 PY 1998 BP 51 EP 56 PG 6 WC Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods; Engineering, Multidisciplinary SC Computer Science; Engineering GA BM99U UT WOS:000080386700009 ER PT S AU Feary, M Sherry, L AF Feary, M Sherry, L GP HFES HFES HFES TI Evaluation of a formal methodology for developing aircraft vertical flight guidance training material SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc AB Aircraft automation, particularly the automation surrounding vertical navigation, has been cited as an area of training difficulty and a source of confusion during operation. A number of incidents have been attributed to a lack of crew understanding of what the automation is doing. This paper describes the translation of information from a formal methodology used in design of an automated vertical guidance system to a training package, and an experiment that tested the new training. This study is part of a larger project to improve the recognition and understanding of the "objectives and behaviors" of automated systems through a formal methodology. The formal method, referred to as the operational procedures methodology, integrates the design of the system with the design of the training and display information requirements for that system (Sherry, 1995). The study utilized a training package designed to teach the vertical guidance portion of the Flight Mode Annunciator (FMA), as seen in normal operations of the Boeing MD-11. The results of the study showed that this type of training can be successfully delivered via a computer based training device. Additionally, a study in a full cockpit simulator showed that the training, coupled with the new display, provided significantly less errors on a simulated flight, although the training alone did not provide significantly better performance. C1 NASA, Ames Res Ctr, SJSU, Moffett Field, CA 94035 USA. RP Feary, M (reprint author), NASA, Ames Res Ctr, SJSU, Moffett Field, CA 94035 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 72 EP 76 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900015 ER PT S AU Latorella, KA AF Latorella, KA GP HFES HFES HFES TI Effects of modality on interrupted flight deck performance: Implications for data link SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc AB Externally-imposed tasks frequently interrupt ongoing task performance in the commercial flight deck. While normally managed without consequence, basic research as well as aviation accident and incident investigations show that interruptions can negatively affect performance and safety. This research investigates the influence of interruption and interrupted task modality on pilot performance in a simulated commercial flight deck. Fourteen current commercial airline pilots performed approach scenarios in a fixed-base flight simulator. Air traffic control instructions, conveyed either aurally or visually (via a data link system) interrupted a visual task (obtaining information from the Flight Management System) and an auditory task (listening to the automated terminal information service recording). Some results confirm the hypothesized performance advantage of cross-modality conditions, more compelling nature of auditory interruptions, and interruption-resistance of auditory ongoing tasks. However, taken together, results suggest the four interaction conditions had different effects on pilot performance. These results have implications for the design of data link systems, and for facilitating interruption management through interface design, aiding, and training programs. C1 NASA, Langley Res Ctr, Crew Vehicle Integrat Branch, Hampton, VA 23681 USA. RP Latorella, KA (reprint author), NASA, Langley Res Ctr, Crew Vehicle Integrat Branch, MS 152, Hampton, VA 23681 USA. NR 26 TC 19 Z9 19 U1 0 U2 2 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 87 EP 91 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900018 ER PT S AU Orasanu, J Fischer, U McDonnell, LK Davison, J Haars, KE AF Orasanu, J Fischer, U McDonnell, LK Davison, J Haars, KE GP HFES HFES HFES TI How do flight crews detect and prevent errors? Findings from a flight simulation study SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc AB In order for a team to maintain safety in a high-risk engineered environment, its members must monitor each other's behavior, as well as the situation. The advantage of a team structure is that members can support each other, catching errors and preventing problems from developing into serious situations. In its analysis of aviation accidents in which crew behavior played a role, the National Transportation Safety Board (1994) observed that most of those accidents involved "monitoring and challenging" errors. After an error occurred, the crew either failed to detect it or to communicate effectively in order to ameliorate the outcome. This paper describes a simulator study that examined two factors thought to affect monitoring and challenging: (a) level of physical risk in a developing situation and (b) degree of face threat involved in a challenge. Events were scripted to present errors committed by a confederate pilot (high face threat) or problems developing outside the flight deck (low face threat). Videotapes of performance showed that captains were more assertive and responded earlier than first officers, often preventing the problems from developing. This difference, however, was only evident in high-risk situations. First officers were more sensitive to face threat than captains, indicating a need for techniques to overcome limits to error mitigation in high-face threat situations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Orasanu, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 6 TC 5 Z9 5 U1 0 U2 0 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 191 EP 195 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900039 ER PT S AU Mosier, KL Dunbar, M McDonnell, L Skitka, LJ Burdick, M Rosenblatt, B AF Mosier, KL Dunbar, M McDonnell, L Skitka, LJ Burdick, M Rosenblatt, B GP HFES HFES HFES TI Automation bias and errors: Are teams better than individuals? SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc ID PERFORMANCE AB A series of recent studies has identified two classes of errors that commonly emerge in highly automated decision environments: (1) omission errors, defined as failures to respond to system irregularities or events because automated devices fail to detect or indicate them; and (2) commission errors, which occur when people incorrectly follow an automated directive or recommendation, without verifying it against other available information, or in spite of contra-indications from other sources of information. These errors are hypothesized to be the result of "automation bias," the use of automation as a heuristic replacement for vigilant information seeking and processing. Two concurrent studies, using students and professional pilots as participants, demonstrated the persistence of automation bias in crews compared with solo performers, despite display enhancements and explicit training to verify automated functioning. Training that focused on automation bias and associated errors successfully reduced omission errors in students. Pilot performance during the experimental legs was most highly predicted by performance on the control leg and by event importance. The previously found "phantom memory" phenomenon associated with a false engine fire event persisted in crews. C1 San Jose State Univ, NASA Ames, San Jose, CA 95192 USA. RP Mosier, KL (reprint author), San Jose State Univ, NASA Ames, San Jose, CA 95192 USA. OI Skitka, Linda/0000-0002-7078-0650 NR 15 TC 0 Z9 0 U1 0 U2 1 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 201 EP 205 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900041 ER PT S AU Tyler, SW Neukom, C Logan, M Shively, J AF Tyler, SW Neukom, C Logan, M Shively, J GP HFES HFES HFES TI The MIDAS human performance model SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc AB A unique software tool for conducting human factors analyses of complex human-machine systems has been developed at NASA Ames Research Center. Called the Mac-Machine Integration Design and Analysis System (MIDAS), this simulation system contains models of human performance that can be used to evaluate candidate procedures, controls, and displays prior to more expensive and time consuming hardware simulators and human subject experiments. While this tool has been successfully applied to research issues in several domains, particularly in aeronautics, a desire to expand its functionality and its ease of use has led to the construction of a new object-oriented system. This new version of MIDAS contains a substantially modified human performance model, one that is aimed at being more consistent with empirical data on human behavior and more natural for designers to apply to the analyses of complex new designs. This paper offers a summary of this new human performance model, together with justifications for some of its main components, and indicates plans for its subsequent verification and validation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Tyler, SW (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 12 TC 4 Z9 5 U1 0 U2 2 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 320 EP 324 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900066 ER PT S AU Corker, KM Pisanich, G AF Corker, KM Pisanich, G GP HFES HFES HFES TI Cognitive performance for multiple operators in complex dynamic airspace systems: Computational representation and empirical analyses SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc AB This paper presents a set of studies in full mission simulation and the development of a predictive computational model of human performance in control of complex airspace operations. NASA and the FAB have initiated programs of research and development to provide flight crew, airline operations and air traffic managers with automation aids to increase capacity in enroute and terminal area to support the goals of safe, flexible, predictable and efficient operations. In support of these developments, we present a computational model to aid design that includes representation of multiple cognitive agents (both human operators and intelligent aiding systems). The demands of air traffic management require representation of many intelligent agents sharing world-models, coordinating action/intention, and scheduling goals and actions in a potentially unpredictable world of operations. The operator-model structure includes attention functions, action priority, and situation assessment. The cognitive model has been expanded to include working memory operations including retrieval from long-term store, and interference. The operator's activity structures have been developed to provide for anticipation through knowledge of the intention and action of remote operators. System stability and operator actions can be predicted by using the model. The model's predictive accuracy was verified using the full-mission simulation data of commercial flight deck operations with advanced air traffic management techniques. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Corker, KM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 12 TC 1 Z9 1 U1 1 U2 1 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 341 EP 345 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900070 ER PT S AU Orasanu, J Serfaty, D AF Orasanu, J Serfaty, D GP HFES HFES HFES TI Fifteen years of team research: What have we learned? Where are we going? SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Orasanu, J (reprint author), NASA, Ames Res Ctr, AFO,Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 5 TC 0 Z9 0 U1 0 U2 2 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 355 EP 358 PG 4 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900073 ER PT S AU McCandless, JW Ellis, SR Adelstein, BD AF McCandless, JW Ellis, SR Adelstein, BD GP HFES HFES HFES TI Localization of a monocularly presented virtual object with delayed visual feedback SO PROCEEDINGS OF THE HUMAN FACTORS AND ERGONOMICS SOCIETY 42ND ANNUAL MEETING, VOLS 1 AND 2 SE HUMAN FACTORS AND ERGONOMICS SOCIETY ANNUAL MEETING PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual Meeting of the Human-Factors-and-Ergonomics-Society CY OCT 05-09, 1998 CL CHICAGO, IL SP Human Factors & Ergon Soc ID ABSOLUTE MOTION PARALLAX; DEPTH-PERCEPTION; DISTANCE; ENVIRONMENTS AB Observers adjusted a pointer to match the depicted distance of a monocular virtual object viewed in a see-through head-mounted display. Distance information was available through motion parallax produced as the observers rocked back and forth. The apparent stability of the virtual object was impaired by the time delay between the observers' head motions and the corresponding change in the object position on the display. Localizations were made for four time delays (31 ms, 64 ms, 131 ms, and 197 ms) and three depicted distances (75 cm, 95 cm, and 113 cm). The errors in localizations increased systematically with time delay and depicted distance. C1 NASA, Ames Res Ctr, Human Informat Proc Res Branch, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Human Informat Proc Res Branch, Moffett Field, CA 94035 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU HUMAN FACTORS AND ERGONOMICS SOC PI SANTA MONICA PA PO BOX 1369, SANTA MONICA, CA 90406-1369 USA SN 1071-1813 BN 0-945289-11-1 J9 HUM FAC ERG SOC P PY 1998 BP 1595 EP 1599 PG 5 WC Engineering, Aerospace; Computer Science, Cybernetics; Engineering, Multidisciplinary; Engineering, Industrial SC Engineering; Computer Science GA BM69U UT WOS:000079494900332 ER PT J AU Bondyopadhyay, PK Chatterjee, PK Chakrabarti, U AF Bondyopadhyay, PK Chatterjee, PK Chakrabarti, U TI Special Issue on the Fiftieth Anniversary of the Transistor SO PROCEEDINGS OF THE IEEE LA English DT Editorial Material C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Texas Instruments Inc, Dallas, TX 75265 USA. Lucent Technol, Breinigsville, PA 18031 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 3 EP 6 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000001 ER PT J AU Bondyopadhyay, PK AF Bondyopadhyay, PK TI In the beginning SO PROCEEDINGS OF THE IEEE LA English DT Article DE inversion layer; junction transistor; minority carrier injection theory; negative resistance; point-contact transistor; semiconductor amplifier; transit time delay ID CONCEPTION; TRANSISTOR AB The junction transistor, technologically the most important solid-state device, invented theoretically by W. B, Shockley on January 23, 1948, brought about the semiconductor revolution. That invention was triggered by the experimental discovery of the point-contact transistor by W. Brattain and J. Bardeen 38 days earlier. Bardeen's notebook entries at Bell Telephone Laboratories for the crucial 100-day period November 21, 1947-February 29, 1948 have been examined to ascertain why this winner of two Nobel Prizes in physics could not invent the junction transistor. It was found that the boundary between the thin p-type inversion layer and the n-type bulk germanium semiconductor in their original point-contact transistor discovery was characterized as a "high resistance boundary" in macroscopic electrical engineering terms by Bardeen, the electrical engineer turned mathematical physicist. Pages from Shockley's notebook are reproduced in full to show what exactly he was thinking on December 16, 1947, the day the point-contact transistor was experimentally discovered by Brattain and Bardeen. The origin of U.S. Patent 2524035 has been traced to the Bell Telephone Laboratories notebook pages of its inventors and examined. It is shown that this patent could not be considered as the first patent describing Shockley's revolutionary theoretical invention of the minority carrier injection concept underlying bipolar transistor action. C1 NASA, Lyndon B Johnson Space Ctr, Av Hardware Branch, Houston, TX 77058 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Av Hardware Branch, Houston, TX 77058 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 63 EP 77 DI 10.1109/5.658760 PG 15 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000012 ER PT J AU Bondyopadhyay, PK AF Bondyopadhyay, PK TI Moore's law governs the silicon revolution SO PROCEEDINGS OF THE IEEE LA English DT Article DE engines of innovation; integrated circuit complexity; Moore's law; silicon age; silicon revolution; transistors in microchips AB The genesis and dynamics of Moore's law governing the silicon revolution are briefly outlined. C1 NASA, Lyndon B Johnson Space Ctr, Av Hardware Branch, Houston, TX 77058 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Av Hardware Branch, Houston, TX 77058 USA. NR 11 TC 28 Z9 30 U1 0 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 78 EP 81 DI 10.1109/5.658761 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000013 ER PT J AU Bondyopadhyay, PK AF Bondyopadhyay, PK TI W=Shockley the transistor pioneer - Portrait of an inventive genius SO PROCEEDINGS OF THE IEEE LA English DT Article DE invention of the transistor; junction transistor; monolithic semiconductor shift register; Moore's law negative resistance device; semiconductor revolution; Shockley diode; Shockley patents; silicon solar cells; Silicon Valley; switching diode; switching transistor AB A forensic historian of science and technology suspends Moore's law for a few moments and with the readers embarks on a journey through W=Shockley's (as was his trademark signature) patents to capture a glimpse of his creative mind. C1 NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. NR 13 TC 0 Z9 0 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 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 191 EP 217 DI 10.1109/5.658771 PG 27 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000023 ER PT J AU Bondyopadhyay, PK AF Bondyopadhyay, PK TI Under the glare of a thousand suns - The pioneering works of Sir J.C. Bose SO PROCEEDINGS OF THE IEEE LA English DT Article DE differential conductivity; galena detector; millimeter-wave detector; millimeter-wave wireless autocoherer; polarizing crystal detector; self-restoring coherer; semiconductor diode AB The origin of solid-state diode detectors of wireless waves has been traced to Sir J. C. Bose's pioneering millimeter-wave propagation experiments with certain polarizing crystals during 1896-1898. His seminal paper published in the January 1897 issue of the Proceedings of the Royal Society is reproduced in this issue to commemorate the one hundredth anniversary of the invention of the solid-state diode detector The world's first patent on the solid-state diode detector, invented by Bose and taken out in the United States, is also reproduced in full in this issue. Bose's further pioneering work with diode detectors, then known as "self-restoring coherers," is discussed, in particular his invention of the "iron-mercury-iron contact with a telephone " detector that received the first transatlantic wireless signal of Marconi on December 12, 1901. C1 NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. NR 18 TC 1 Z9 1 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 218 EP 224 DI 10.1109/5.658772 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000024 ER PT J AU Bondyopadhyay, PK AF Bondyopadhyay, PK TI Sir J. C. Bose's diode detector received Marconi's first transatlantic wireless signal of December 1901 (the "Italian Navy Coherer" scandal revisited) SO PROCEEDINGS OF THE IEEE LA English DT Article DE detection of first transatlantic wireless signal; Italian Navy coherer; Marconi's 1901 transatlantic wireless experiment; mercury coherer with a telephone; origin of the Italian Navy coherer; self-restoring coherer; semiconductor diode detector AB The true origin of the "mercury coherer with a telephone" receiver that was used by G. Marconi to receive the first transatlantic wireless signal on December 12, 1901, has been investigated and determined. Incontrovertible evidence is presented to show that this novel wireless detection device was invented by Sir. J. C. Bose of Presidency College, Calcutta, India. His epoch-making work was communicated by Lord Rayleigh, F.R.S., to the Royal Society, London, U.K., on March 6, 1899, and read at the Royal Society Meeting of Great Britain on April 27, 1899. Soon after, it was published in the Proceedings of the Royal Society. Twenty-one months after that disclosure (in February 1901, as the records indicate), Lieutenant L. Solari of the Royal Italian Navy, a childhood friend of G. Marconi's, experimented with this detector device and presented a trivially modified version to Marconi, who then applied for a British patent on the device. Surrounded by a scandal, this detection device, actually a semiconductor diode, is known to the outside world as the "Italian Navy Coherer." This scandal, first brought to light by Prof. A. Banti of Italy, has been critically analyzed and expertly presented in a time sequence of events by British historian V. J. Phillips but without discovering the tote origin of the novel detector In this paper, the scandal is revisited and the mystery of the device's true origin is solved, thus correcting the century-old misinformation on an epoch-making chapter in the history of semiconductor devices. C1 NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. RP Bondyopadhyay, PK (reprint author), NASA, Lyndon B Johnson Space Ctr, Avion Hardware Branch, Houston, TX 77058 USA. NR 34 TC 7 Z9 7 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD JAN PY 1998 VL 86 IS 1 BP 259 EP 285 DI 10.1109/5.658778 PG 27 WC Engineering, Electrical & Electronic SC Engineering GA YU436 UT WOS:000071717000031 ER PT B AU Anderson, JL Radnor, M Peterson, JW AF Anderson, JL Radnor, M Peterson, JW BE Xu, QR Wu, X Chen, J TI "On creating new horizons: Integrating non-linear considerations to better manage the present from the future" SO PROCEEDINGS OF THE SECOND INTERNATIONAL SYMPOSIUM ON MANAGEMENT OF TECHNOLOGY LA English DT Proceedings Paper CT 2nd International Symposium on Management of Technology CY NOV 26-28, 1998 CL Hangzhou, PEOPLES R CHINA SP Zhejiang Univ, Chinese Acad Sci, State Educ Minist, NSF China, EU Delegat EC, EASTCOM Grp, HiSense Grp Ltd Co, Zhongxing Telecom Ltd Co, Hongta Grp, Qingqi Grp, Microtek Co AB When preparing to shape the future, planners and policy makers must first integrate economic, political, cultural, and technology considerations with geo-strategic realities, national interests, developing alliances and existing capabilities. This synthesis must lead to a vision for the enterprise, be it a country, a business, or a project. The synthesis must also act as a catalyst, combining current realities, constructive confrontation, creativity, and intuition with the uncertainties about the future. These in turn, enable longer term decisions about investments, resource allocations and capability nurturing. Such considerations will depend on the context and circumstances of the end game. To this end, it is important that the planners and policy-makers create new planning horizons, debate alternatives and integrate non-linear thinking into their thought processes, rather than argue about the form, the probabilities and the sources of the data points. In a departure from the tenets of formal scenario planning, a methodology is proposed that has the virtues of an informal, flexible, and adaptable approach. It allows for consideration of the difficult-to-quantify "softer factors" often overlooked or ignored in the more formal deterministic modeling. C1 NASA, Washington, DC 20546 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU WORLD PUBLISHING CORPORATION PI BEIJING PA 137 CHAONEI DAJIE, BEIJING 100010, PEOPLES R CHINA BN 7-80003-435-6 PY 1998 BP 32 EP 41 PG 10 WC Management SC Business & Economics GA BAK42 UT WOS:000222634300004 ER PT B AU Blumenstock, KA Lee, KY Schepis, JP AF Blumenstock, KA Lee, KY Schepis, JP BE Allaire, PE Trumper, DL TI A spaceflight magnetic rearing equipped optical chopper with six-axis active control SO PROCEEDINGS OF THE SIXTH INTERNATIONAL SYMPOSIUM ON MAGNETIC BEARINGS LA English DT Proceedings Paper CT 6th International Symposium on Magnetic Bearings CY AUG 05-07, 1998 CL MIT, CAMBRIDGE, MA SP Univ Virginia, MIT HO MIT AB This paper describes the development of an ETU (Engineering Test Unit) rotary optical chopper with magnetic bearings. An ETU is required to be both flight-like, nearly identical to a flight unit without the need for material certifications, and demonstrate structural and performance integrity. A prototype breadboard design previously demonstrated the feasibility of meeting flight performance requirements using magnetic bearings. The chopper mechanism is a critical component of the High Resolution Dynamics Limb Sounder (HIRDLS) which will be flown on EOS-CHEM (Earth Observing System-Chemistry). Particularly noteworthy are the science requirements which demand high precision positioning and minimal power consumption along with full redundancy of coils and sensors in a miniature, lightweight package. The magnetic bearings are unique in their pole design to minimize parasitic losses and utilize collocated optical sensing, The motor is of an unusual disk-type ironless stator design. The ETU design has evolved from the breadboard design. A number of improvements have been incorporated into the ETU design. Active thrust control has been added along with changes to improve sensor stability, motor efficiency, and touchdown and launch survivability. It was necessary to do all this while simultaneously reducing the mechanism volume, Flight-like electronics utilize a DSP (Digital Signal Processor) and contain all sensor electronics and drivers on a single five inch by nine inch circuit board. Performance test results are reported including magnetic bearing and motor rotational losses. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Blumenstock, KA (reprint author), NASA, Goddard Space Flight Ctr, Code 544, Greenbelt, MD 20771 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU TECHNOMIC PUBL CO INC PI LANCASTER PA 851 NEW HOLLAND AVE, BOX 3535, LANCASTER, PA 17604 USA BN 1-56676-710-5 PY 1998 BP 95 EP 105 PG 11 WC Engineering, Mechanical SC Engineering GA BP86L UT WOS:000086446500011 ER PT S AU Ames, C Burleigh, S Mitchell, S Huynh, T AF Ames, C Burleigh, S Mitchell, S Huynh, T BE Nunamaker, JF TI Applications of web-based workflow SO PROCEEDINGS OF THE THIRTY-FIRST HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES, VOL I: COLLABORATION SYSTEMS AND TECHNOLOGY TRACK SE PROCEEDINGS OF THE ANNUAL HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES LA English DT Proceedings Paper CT 31st Hawaii International Conference on System Sciences (HICSS-31) CY JAN 06-09, 1998 CL KOHALA COAST, HI SP Univ Hawaii, Coll Business Adm AB A web-based workflow system was developed at the Jet Propulsion Laboratory and several pilot applications were developed. We give an overview of the architecture and functionality of the workflow system, describe three pilot workflows that have been or are being deployed, and relate lessons learned. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 0 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 SN 1060-3425 BN 0-8186-8255-8 J9 P ANN HICSS PY 1998 BP 79 EP 87 PG 9 WC Computer Science, Information Systems; Information Science & Library Science; Management SC Computer Science; Information Science & Library Science; Business & Economics GA BK43C UT WOS:000072155700011 ER PT S AU Becker, JC Nitzberg, B Van Der Wijngaart, RF AF Becker, JC Nitzberg, B Van Der Wijngaart, RF BE ElRewini, H TI Predicting cost/performance trade-offs for Whitney: A commodity computing cluster SO PROCEEDINGS OF THE THIRTY-FIRST HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES, VOL VII: SOFTWARE TECHNOLOGY TRACK SE PROCEEDINGS OF THE ANNUAL HAWAII INTERNATIONAL CONFERENCE ON SYSTEM SCIENCES LA English DT Proceedings Paper CT 31st Hawaii International Conference on System Sciences (HICSS-31) CY JAN 06-09, 1998 CL KOHALA COAST, HI SP Univ Hawaii, Coll Business Adm AB Recent advances in low-end processor and network technology have made it possible to build a "supercomputer" out of commodity components, We develop simple models of the NAS Parallel Benchmarks version 2 (NPB 2) to explore the cost/performance trade-offs involved in building a balanced parallel computer supporting a scientific workload. By measuring single processor benchmark performance, network latency and network bandwidth, and using closed form expressions detailing the number and size of messages sent by each benchmark, our models predict benchmark performance to within 30%. A comparison based on total system cost reveals that current commodity technology (200 MHz Pentium Pros with 100baseT Ethernet) is well balanced for the NPBs up to a total system cost of around $1,000,000. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. NR 0 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 SN 1060-3425 BN 0-8186-8255-8 J9 P ANN HICSS PY 1998 BP 504 EP 513 PG 10 WC Computer Science, Information Systems; Information Science & Library Science; Management SC Computer Science; Information Science & Library Science; Business & Economics GA BK43J UT WOS:000072158800055 ER PT B AU Freed, M Remington, R AF Freed, M Remington, R BE Gernsbacher, MA Derry, SJ TI A conceptual framework for predicting error in complex human-machine environments SO PROCEEDINGS OF THE TWENTIETH ANNUAL CONFERENCE OF THE COGNITIVE SCIENCE SOCIETY LA English DT Proceedings Paper CT 20th Annual Conference of the Cognitive-Science-Society CY AUG 01-04, 1998 CL UNIV WISCONSIN, MADISON, WI SP Cognit Sci Soc HO UNIV WISCONSIN AB We present a GOMS-MHP style model-based approach to the problem of predicting human habit capture errors. Habit captures occur when the model fails to allocate limited cognitive resources to retrieve task-relevant information from memory. Lacking the unretrieved information, decision mechanisms act in accordance with implicit default assumptions, resulting in error when relied upon assumptions prove incorrect. The model helps interface designers identify situations in which such failures are especially likely. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Freed, M (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU LAWRENCE ERLBAUM ASSOC PUBL PI MAHWAH PA 10 INDUSTRIAL AVE, MAHWAH, NJ 07430 USA BN 0-8058-3231-9 PY 1998 BP 356 EP 361 PG 6 WC Language & Linguistics; Psychology; Psychology, Multidisciplinary; Psychology, Experimental SC Linguistics; Psychology GA BR96W UT WOS:000168193500070 ER PT B AU Singh, M AF Singh, M BE Khor, KA Srivatsan, TS Moore, JJ TI Affordable fabrication and properties of silicon carbide-based ceramics SO PROCESSING AND FABRICATION OF ADVANCED MATERIALS VI, VOLS 1 & 2 LA English DT Proceedings Paper CT International Symposium on Processing and Fabrication of Advanced Materials CY NOV 24-26, 1997 CL SINGAPORE, SINGAPORE SP Nanyang Technol Univ, Sch Mech & Prod Engn, Inst Mat, Minerals Met & Mat Soc, Adv Mat Res Ctr DE fabrication; affordable process; silicon carbide; microporous carbon; elastic modulus; fracture toughness; flexural strength; flexural creep ID MICROPOROUS CARBON MATERIALS; REACTIVE MELT INFILTRATION; MECHANICAL-PROPERTIES; ANELASTIC PROPERTIES; MICROSTRUCTURE; PREFORMS; ALLOYS AB An affordable processing technique for the fabrication of silicon carbide-based ceramics is presented. This process consists of the production of microporous carbon preforms and their subsequent infiltration with liquid silicon or silicon-refractory metal (Mo, Nb) alloys. The microporous preforms are made by the pyrolysis of a polymerized resin mixture with good control of pore volume and pore size. The process gives good control of microstructure and morphology of silicon carbide-based materials. Transmission electron microscopy analysis indicates the bi-modal grain size distribution in these materials. Mechanical properties (elastic modulus, fracture toughness, flexural strength, and flexural creep) of a wide variety of reaction-formed silicon carbide-based ceramics have been discussed. C1 NYMA Inc, NASA, Lewis Res Ctr Grp, Cleveland, OH 44135 USA. RP Singh, M (reprint author), NYMA Inc, NASA, Lewis Res Ctr Grp, Cleveland, OH 44135 USA. NR 25 TC 0 Z9 0 U1 0 U2 2 PU IOM COMMUNICATIONS LTD PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON SW1Y 5DB, ENGLAND BN 1-86125-039-8 PY 1998 BP 743 EP 752 PG 10 WC Materials Science, Ceramics; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Composites SC Materials Science; Metallurgy & Metallurgical Engineering GA BP03C UT WOS:000083931500063 ER PT B AU Ritzert, F Arenas, D Keller, D Vasudevan, V AF Ritzert, F Arenas, D Keller, D Vasudevan, V BE Li, BQ TI The effect of alloying on topologically close packed phase instability in advanced nickel-base superalloy Rene N6 SO PROCESSING OF METALS AND ADVANCED MATERIALS: MODELING, DESIGN AND PROPERTIES LA English DT Proceedings Paper CT International Symposium on Processing of Metals and Advanced Materials - Modeling, Design and Properties at the 1998 TMS Annual Meeting CY FEB 16-19, 1998 CL SAN ANTONIO, TX SP Minerals Met & Mat Soc, Mat Design & Mfg Div, Synthesis Control & Anal Mat Proc Comm, Minerals Met & Mat Soc, Extract & Proc Div, Synthesis Control & Analy Mat Proc Comm AB An investigation was conducted to describe topologically close packed (TCP) phase instability as a function of composition in the advanced Ni-base superalloy Rene N6. TCP phases are detrimental to overall high-temperature performance of Ni-base superalloys because of their brittle nature and because they deplete the Ni-rich matrix of potent solid solution strengthening elements. Thirty-four variations of polycrystalline Rene N6 determined from a design-of-experiments approach were cast and homogenized at 1315 degrees C for 80 hours followed by exposure at 1093 degrees C for 400 hours to promote TCP formation. The alloys had the following composition ranges in atomic percent: cobalt 10.61 to 16.73, Mo 0.32 to 1.34%, W 1.85 to 2.52%, Re 1.80 to 2.11%, Ta 2.36 to 3.02%, Al 11.90 to 14.75%, and Cr 3.57 to 6.23%. Physical and chemical characteristics of all microstructures obtained were described using various analytical techniques. From these observations, a mathematical description of TCP occurrence (sigma and P phase) was generated for polycrystalline Rene N6. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ritzert, F (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 3 Z9 3 U1 3 U2 5 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-395-3 PY 1998 BP 163 EP 174 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BK53P UT WOS:000072467400014 ER PT J AU Raman, G AF Raman, G TI Advances in understanding supersonic jet screech: Review and perspective SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review ID SHOCK-CELL STRUCTURES; RECTANGULAR JETS; UNDEREXPANDED JETS; OSCILLATION MODES; MIXING ENHANCEMENT; INSTABILITY WAVES; TONES; NOZZLES; NOISE; AEROACOUSTICS AB Screech tones are produced by imperfectly expanded jets under certain conditions. This paper provides an overview of developments in the field of supersonic jet screech. The overview includes a historical background, summary of recent developments, and a critical assessment of our current understanding of screech. The subject material has been categorized as described in the table of contents given below. (C) 1998 Elsevier Science Ltd. C1 NYMA Inc, Expt Fluid Dynam Sect, NASA, Lewis Res Ctr Grp, Brook Pk, OH 44142 USA. RP Raman, G (reprint author), NYMA Inc, Expt Fluid Dynam Sect, NASA, Lewis Res Ctr Grp, 2001 Aerosp Pkwy, Brook Pk, OH 44142 USA. NR 171 TC 53 Z9 54 U1 2 U2 13 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 JAN-FEB PY 1998 VL 34 IS 1-2 BP 45 EP 106 DI 10.1016/S0376-0421(98)00002-5 PG 62 WC Engineering, Aerospace SC Engineering GA 114ZG UT WOS:000075638600002 ER PT J AU Bailey, SG Flood, DJ AF Bailey, SG Flood, DJ TI Space photovoltaics SO PROGRESS IN PHOTOVOLTAICS LA English DT Review ID SOLAR-CELLS; EFFICIENCY AB The key elements of spacecraft photovoltaic cell and array design are identified and the historical development of space photovoltaics is discussed. Important parameters are listed for earth orbiting, near-earth, near-sun and outer planetary missions. The earth-orbiting missions are described within the context of low earth orbit, mid-altitude earth orbit and geosynchronous earth orbit. Requirements governed by the choice of mission, such as total power, insolation, temperature, radiation environment and stowed volume, are discussed with respect to the solar cell parameters important to that mission (conversion efficiency, weight, tolerance to the space radiation environment, cost and availability). Array parameters (dollars per watt, watts per kilogram, watts per square meter) are discussed for three types of arrays (rigid, lightweight flexible and concentrator). Progress in cell efficiencies is noted with a record GaInP/GaAs cell efficiency of 26.9%. Recent advances in thin-film cells (copper-indium diselenide and amorphous silicon) are discussed. Manufacturing capability and progress in multiple bandgap cells is noted. Space photovoltaics can look forward to an exciting next 10 years as the demand for a variety of satellites continues to grow. (C) 1998 John Wiley & Sons, Ltd. C1 NASA, Lewis Res Ctr, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. RP Bailey, SG (reprint author), NASA, Lewis Res Ctr, Photovolta & Space Environm Branch, MS 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 28 TC 52 Z9 52 U1 4 U2 31 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1062-7995 J9 PROG PHOTOVOLTAICS JI Prog. Photovoltaics PD JAN-FEB PY 1998 VL 6 IS 1 BP 1 EP 14 PG 14 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA ZD177 UT WOS:000072659100001 ER PT S AU Armitage, D Larimer, J AF Armitage, D Larimer, J BE Wu, MH TI Liquid crystal response time SO PROJECTION DISPLAYS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Projection Displays IV CY JAN 27-29, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE liquid crystals; nematics; displays; color-sequential display; projector; color-sequential projector AB The response of a nematic liquid-crystal reflective device is computed using the Berreman codes incorporated in the NASA ViDEOS software. The results are applied to a color-sequential projection system, and show the throughput limitations imposed by the nematic response time. The temperature dependence of nematic viscosity is included, to demonstrate the increase in response speed at projector operating temperatures. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Armitage, D (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 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 0-8194-2736-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3296 BP 19 EP 29 DI 10.1117/12.305534 PG 11 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL04P UT WOS:000074113600003 ER PT S AU Wang, Y AF Wang, Y BE Wu, MH TI Scrolling color projection display using surface plasmon tunable filters SO PROJECTION DISPLAYS IV SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Projection Displays IV CY JAN 27-29, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE surface plasmon; electro-optics; display; projector; LCD AB Surface plasmon tunable filter (SPTF) is a new technology underdevelopment at Jet Propulsion Lab. When applying to LCD projectors, SPTF can simplify the system structure, and enhance the efficiency. A scrolling SPTF which consists three SPTFs can generate scrolling red, green and blue colors, is able to enhance the efficiency of a single panel LCD projector up to the same level as a three panel LCD projector. A scrolling SPTF which consists six SPTFs and can generate two set of scrolling RGB colors, will enable a single panel LCD projector to be 100% more efficiency than the current three panel LCD projector. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 2 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 0-8194-2736-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3296 BP 149 EP 153 DI 10.1117/12.305514 PG 5 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BL04P UT WOS:000074113600017 ER PT J AU Robinson, RD Ake, TB Lindler, DJ Heap, SR Carpenter, KG Leckrone, DS Maran, SP Smith, AM Brandt, JC Beaver, EA Boggess, A Ebbets, DC Hutchings, JB Jura, M Linsky, JL Savage, BD Trafton, LM Walter, FM Weymann, RJ AF Robinson, RD Ake, TB Lindler, DJ Heap, SR Carpenter, KG Leckrone, DS Maran, SP Smith, AM Brandt, JC Beaver, EA Boggess, A Ebbets, DC Hutchings, JB Jura, M Linsky, JL Savage, BD Trafton, LM Walter, FM Weymann, RJ TI The Goddard high resolution spectrograph: Post-COSTAR characteristics SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article AB We review changes to the characteristics of the Goddard High Resolution Spectrograph (GHRS) which resulted from the installation of the Corrective Optics Space Telescope Axial Replacement (COSTAR) on the Hubble Space Telescope. The introduction of two new optical elements into the light path altered the spectral distribution of the Light, decreasing the amount of light striking the instrument by about 30% at wavelengths greater than 1200 Angstrom and effectively eliminated all radiation at wavelengths less than 1130 Angstrom. However, at the longer wavelengths the improved focus offset this loss when the Large Science Aperture (LSA) was used and increased the overall throughput of the Small Science Aperture (SSA) by a factor of 2. The improved focus also enhanced the spectral resolution of LSA observations and improved the ability of the instrument to observe in crowded fields. C1 Comp Sci Corp, Goddard Space Flight Ctr, Astron Program, Greenbelt, MD 20771 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Ball Aerosp Syst Grp, Boulder, CO 80306 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90024 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Texas, Mcdonald Observ, Austin, TX 78712 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. SUNY Stony Brook, Dept Earth & Space Sci, Stony Brook, NY 11794 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. RP Robinson, RD (reprint author), Comp Sci Corp, Goddard Space Flight Ctr, Astron Program, Code 681 CSC, Greenbelt, MD 20771 USA. RI heap, sara/E-2237-2012; Carpenter, Kenneth/D-4740-2012 NR 12 TC 14 Z9 14 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD JAN PY 1998 VL 110 IS 743 BP 68 EP 78 DI 10.1086/316116 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA YU680 UT WOS:000071743200010 ER PT J AU Considine, G Curry, JA AF Considine, G Curry, JA TI Effects of entrainment and droplet sedimentation on the microphysical structure of stratus and stratocumulus clouds SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE boundary-layer cloud; cloud microphysics; drizzle; parametrization ID BOUNDARY-LAYER; CUMULUS CLOUDS; MIXED LAYER; MODEL; SPECTRA; ASTEX AB A new cloud model has been developed based upon a reconsideration of cloud-top entrainment mechanisms. A finite-thickness entrainment layer at cloud top allows the cloudy air to lose Liquid water to dry entrained air by sedimentation. The model uses a steady-state ensemble of one-dimensional updraughts and downdraughts, combined with a simplified treatment of droplet sedimentation, autoconversion, and collection of cloud drops by drizzle, to examine vertical profiles of cloud liquid-water content and droplet concentration. The model is demonstrated both for idealized cases and in comparison with a nocturnal stratocumulus case from the ASTEX. The sedimentation flux divergence in the entrainment layer at cloud top is shown to have a large impact on the cloud microphysics. C1 NASA, Langley Res Ctr, Hampton, VA 23664 USA. Univ Colorado, Boulder, CO 80309 USA. RP Considine, G (reprint author), NASA, Langley Res Ctr, MS401B, Hampton, VA 23664 USA. NR 27 TC 6 Z9 6 U1 0 U2 2 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JAN PY 1998 VL 124 IS 545 BP 123 EP 150 DI 10.1256/smsqj.54505 PN A PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YX599 UT WOS:000072056700005 ER PT J AU Dee, DP Da Silva, AM AF Dee, DP Da Silva, AM TI Data assimilation in the presence of forecast bias SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE bias estimation; statistical analysis; systematic errors ID STATISTICAL INTERPOLATION; SYSTEMATIC-ERROR; RADIOSONDE DATA; COVARIANCE; SCHEME; MODEL; NMC AB Statistical-analysis methods are generally derived under the assumption that forecast errors are strictly random and zero in the mean. if the short-term forecast, used as the background field in the statistical-analysis equation, is in fact biased, so will the resulting analysis be biased. The only way to account properly for bias in a statistical analysis is to do so explicitly, by estimating the forecast bias and then correcting the forecast prior to analysis. We present a rigorous method for estimating forecast bias by means of data assimilation, based on an unbiased subset of the observing system. The result is a sequential bias estimation and correction algorithm, whose implementation involves existing components of operational statistical-analysis systems. The algorithm is designed to perform on-line, in the context of suboptimal data-assimilation methods which are based on approximate information about forecast-and observation-error covariances. The added computational cost of incorporating online bias estimation and correction into an operational system roughly amounts to one additional solution of the statistical-analysis equation, for a limited number of observations. Off-line forecast-bias estimates based on previously produced assimilated-data sets can be produced as well, using an existing analysis system. We show that our sequential bias estimation algorithm fits into a broader theoretical framework provided by the separate-bias estimation approach of estimation theory. In this framework the bias parameters are defined rather generally and can be used to describe systematic model errors and observational bias as well. We illustrate the performance of the algorithm in a simulated data-assimilation experiment with a one-dimensional forced dissipative shallow-water model. A climate error is introduced into the forecast model via topographic forcing, while random errors are generated by stochastic forcing. In this simple setting our algorithm is well able to estimate and correct the forecast bias caused by this systematic error, and the climate error in the assimilated-data set is virtually eliminated as a result. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Gen Sci Corp, Laurel, MD 20707 USA. RP NASA, Goddard Space Flight Ctr, Data Assimilat Off, Mail Code 910-3, Greenbelt, MD 20771 USA. RI da Silva, Arlindo/D-6301-2012 OI da Silva, Arlindo/0000-0002-3381-4030 NR 37 TC 234 Z9 238 U1 2 U2 13 PU WILEY PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0035-9009 EI 1477-870X J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JAN PY 1998 VL 124 IS 545 BP 269 EP 295 DI 10.1002/qj.49712454512 PN A PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YX599 UT WOS:000072056700011 ER PT J AU Fox-Rabinovitz, MS Rood, RB Lamich, DJ Govindaraju, RC Coy, L Weaver, CJ AF Fox-Rabinovitz, MS Rood, RB Lamich, DJ Govindaraju, RC Coy, L Weaver, CJ TI The impact of diabatic initialization on stratospheric analyses, forecasts, and transport experiments SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE data assimilation; noise control; stratospheric circulation ID DATA ASSIMILATION SYSTEM; NUMERICAL WEATHER PREDICTION; DYNAMIC INITIALIZATION; DIGITAL-FILTER; SPECTRAL MODEL; TIME; SCHEMES; WINDS AB An efficient diabatic initialization procedure has been applied to the entire tropospheric and stratospheric domain within the Goddard Earth Observing System (GEOS) 4-D data assimilation system. The initialization, or initial balancing and noise control technique, is based on the application of the iterative Euler scheme as a highly selective, efficient filter. The GEOS 46-layer General Circulation Model extending to 0.1 hPa was used to produce the first-guess fields within the data assimilation system. This model is also used to calculate medium-range stratospheric forecasts. Within the diabatic initialization approach, the model itself is used to balance the resulting analysis, or initial fields. The diabatic initialization technique appears to be a useful tool which improves stratospheric analyses and forecasts by controlling small-scale high-frequency non-meteorological oscillations and shocks, or spin-up effects resulting from initial imbalances. Changes due to initialization are cumulative with time, hence initialization affects positively the slowly varying components of stratospheric flows, resulting in better representation of climate characteristics. Experiments performed to assess the impact of diabatic initialization on monthly mean analyses and diagnostic fields produced by the data assimilation system show that it provides an efficient noise control, especially for the upper stratospheric levels and in the polar regions. Stratospheric analysis errors have been significantly reduced by applying diabatic initialization. The major characteristics of stratospheric circulation, such as the residual mean meridional circulation, potential vorticity and Eliassen-Palm or EP-flux distributions, are improved when using diabatic initialization. The ozone transport experiments show improvements due to using initialized winds in terms of better agreement with data. Ten-day stratospheric forecast scores have been improved when using initialized, or balanced initial conditions. The initialization method used in the study is easy to implement and is computationally efficient. It appears to be a useful component of a stratospheric data assimilation system. C1 Univ Maryland, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Gen Sci Corp, Laurel, MD 20707 USA. RP Fox-Rabinovitz, MS (reprint author), Suite 200,7501 Forbes Blvd, Seabrook, MD 20706 USA. RI Rood, Richard/C-5611-2008 OI Rood, Richard/0000-0002-2310-4262 NR 42 TC 1 Z9 1 U1 0 U2 1 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JAN PY 1998 VL 124 IS 545 BP 297 EP 315 DI 10.1002/qj.49712454513 PN A PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA YX599 UT WOS:000072056700012 ER PT B AU Johnston, AH AF Johnston, AH GP IEEE TI Radiation effects in advanced microelectronics technologies SO RADECS 97: FOURTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 4th European Conference on Radiation and its Effects on Components and Systems (RADECS 97) CY SEP 15-19, 1997 CL CANNES, FRANCE SP Thomson CSF, Aerospatiale Espace & Def, TEMIC Semiconductors, CEA/DAM, Ministere Culture, Sandia Natl Labs AB The pace of device scaling has increased rapidly in recent years. Experimental CMOS devices have been produced with feature sizes below 0.1 mu m, demonstrating that devices with feature sizes between 0.1 and 0.25 mu m will likely be available in mainstream technologies after the year 2000. This paper discusses how the anticipated changes in device dimensions and design are likely to affect their radiation response in space environments. Traditional problems, such as total dose effects, SEU and Latchup are discussed, along with new phenomena. The tatter include hard errors from heavy ions (microdose and gate-rupture errors), and complex failure modes related to advanced circuit architecture. The main focus of the paper is on commercial devices, which are displacing hardened device technologies in many space applications. However, the impact of device scaling on hardened devices is also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, AH (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4071-X PY 1998 BP 1 EP 16 DI 10.1109/RADECS.1997.698828 PG 16 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BL38P UT WOS:000075341800001 ER PT B AU Lee, CI Johnston, AH AF Lee, CI Johnston, AH GP IEEE TI Comparison of total dose responses on high resolution analog-to-digital converter technologies SO RADECS 97: FOURTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 4th European Conference on Radiation and its Effects on Components and Systems (RADECS 97) CY SEP 15-19, 1997 CL CANNES, FRANCE SP Thomson CSF, Aerospatiale Espace & Def, TEMIC Semiconductors, CEA/DAM, Ministere Culture, Sandia Natl Labs AB Two different 12-bit analog-to-digital converter technologies, CMOS and BiCMOS, from Burr-Brown were compared for total dose responses. The BiCMOS converter appears to be a better candidate for space applications. CMOS devices showed larger degradation with both high dose rate (HDR) and low dose rate (LDR). An external voltage reference can be used for a radiation hardened process 12-bit converter from Analog Devices to maintain accuracy up to 1 Mrad(Si). DATEL's 16-bit hybrid converter showed a low failure level with HDR. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, CI (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4071-X PY 1998 BP 245 EP 250 DI 10.1109/RADECS.1997.698901 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BL38P UT WOS:000075341800042 ER PT B AU LaBel, KA Marshall, PW Marshall, CJ Barth, J Leidecker, H Reed, R Seidleck, CM AF LaBel, KA Marshall, PW Marshall, CJ Barth, J Leidecker, H Reed, R Seidleck, CM GP IEEE TI Comparison of MIL-STD-1773 fiber optic data bus terminals: Single event proton test irradiation, in-flight space performance, and prediction techniques SO RADECS 97: FOURTH EUROPEAN CONFERENCE ON RADIATION AND ITS EFFECTS ON COMPONENTS AND SYSTEMS LA English DT Proceedings Paper CT 4th European Conference on Radiation and its Effects on Components and Systems (RADECS 97) CY SEP 15-19, 1997 CL CANNES, FRANCE SP Thomson CSF, Aerospatiale Espace & Def, TEMIC Semiconductors, CEA/DAM, Ministere Culture, Sandia Natl Labs AB We present a comparison of proton single event ground test results for two generations of MIL-STD-1773 fiber optic data bus interface modules. Single event upset rate prediction techniques for fiber optic data systems are also demonstrated and compared with in-flight space performance. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP LaBel, KA (reprint author), NASA, Goddard Space Flight Ctr, 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 BN 0-7803-4071-X PY 1998 BP 332 EP 338 DI 10.1109/RADECS.1997.698920 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA BL38P UT WOS:000075341800057 ER PT J AU Durante, M George, K Wu, HL Yang, TC AF Durante, M George, K Wu, HL Yang, TC TI Rejoining and misrejoining of radiation-induced chromatin breaks. III. Hypertonic treatment SO RADIATION RESEARCH LA English DT Article ID CHINESE-HAMSTER CELLS; POTENTIALLY LETHAL DAMAGE; HUMAN-LYMPHOCYTES; CHO-CELLS; CHROMOSOMAL-ABERRATIONS; IONIZING-RADIATION; HUMAN FIBROBLASTS; EXPOSURE; RADIOSENSITIVITY; KINETICS AB It has been shown that treatment in anisotonic medium modifies rejoining of radiation-induced breaks in interphase chromosomes. In previous work, we have demonstrated that formation of exchanges in human lymphocytes has a slow component (halftime of 1-2 h), but a fraction of exchanges are also observed in samples assayed soon after exposure. In this paper we studied the effect of hypertonic treatment on rejoining and misrejoining of radiation-induced breaks using fluorescence in situ hybridization of prematurely condensed chromosomes in human lymphocytes. Isolated lymphocytes were irradiated with 7 Gy gamma rays, fused to mitotic hamster cells and incubated in hypertonic solution (0.5 M NaCl) for the period normally allowed for interphase chromosome condensation to occur. The data from hypertonic treatment experiments indicate the presence of a class of interphase chromosome breaks that rejoin and misrejoin very quickly (half-time of 5-6 min). The fast misrejoining of these lesions is considered to be responsible for the initial level of exchanges which we reported previously. No significant effect of hypertonic treatment on the yield of chromosome aberrations scored at the first postirradiation mitosis was detected. (C) 1998 by Radiation Research Society. C1 Univ Naples Federico II, Dipartimento Sci Fis, I-80125 Naples, Italy. Krug Life Sci, Houston, TX 77058 USA. Lyndon B Johnson Space Ctr, Kelsey Seybold Clin, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Durante, M (reprint author), Univ Naples Federico II, Dipartimento Sci Fis, Mostra Oltremare Pad 20, I-80125 Naples, Italy. RI Durante, Marco/K-1315-2014; OI Durante, Marco/0000-0002-4615-553X NR 28 TC 11 Z9 11 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JAN PY 1998 VL 149 IS 1 BP 68 EP 74 DI 10.2307/3579683 PG 7 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA YN894 UT WOS:000071219400009 PM 9421156 ER PT B AU Davis, AB Marshak, A Wiscombe, WJ Cahalan, RF AF Davis, AB Marshak, A Wiscombe, WJ Cahalan, RF BE Mengue, MP TI Insight into three-dimensional radiation transport processes from diffusion theory, with applications to the atmosphere SO RADIATIVE TRANSFER II LA English DT Proceedings Paper CT 2nd International Symposium on Radiation Transfer CY JUL, 1997 CL KUSADASI, TURKEY SP Int Ctr Heat & Mass Transfer, Sci & Technol Council Turkey, METU, Univ Kentucky ID AVERAGED SOLAR FLUXES; STRATOCUMULUS CLOUDS; OPTICAL-THICKNESS; MEDIA; PARAMETERIZATION; ABSORPTION; ALBEDO AB There are two simple approaches to the manifestly 3D problem of radiative transfer in the cloudy atmosphere in the solar spectrum. First, the "weighted plane-parallel" approximation uses standard (homogeneous) plane-parallel theory to compute reflectance R, or any other property, for clear and cloudy conditions; results are then combined linearly according to cloud fraction. Second, the "independent pixel" approximation generalizes the linear weighting scheme by allowing for continuous (rather than Bernoulli) distributions of optical depth tau. Both approaches generally invoke the popular two-stream approximation that is formally analogous to diffusion through a horizontally homogeneous slab. Both approaches explain, via the nonlinear dependence of R on tau, the well-known negative bias delta R between the variable situation and a homogeneous one with the same mean tau. However, neither approach accounts for the horizontal fluxes excited by the strong horizontal variability of extinction by cloud droplets. This suggests that the next logical step is to use 3D photon diffusion theory, without the homogeneity assumption. In this framework, we propose an essentially hydrodynamical model of photon flow that leads to a new analytical result: delta R is proportional to the 1-point covariance of the fluctuations in extinction and the associated perturbation in flux. C1 NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Code 913, Greenbelt, MD 20771 USA. RI Wiscombe, Warren/D-4665-2012 OI Wiscombe, Warren/0000-0001-6844-9849 NR 63 TC 0 Z9 0 U1 0 U2 0 PU BEGELL HOUSE, INC PI NEW YORK PA 145 MADISON AVE, NEW YORK, NY 10016 USA BN 1-567-00116-5 PY 1998 BP 111 EP 139 PG 29 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA BN04D UT WOS:000080479900007 ER PT B AU Meier, DL Godon, P Edgington, S Payne, DG Lind, KR AF Meier, DL Godon, P Edgington, S Payne, DG Lind, KR BE Zensus, JA Taylor, GB Wrobel, JM TI The magnetic switch as the origin of the FRI/FRII break SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We propose that the Fanaroff & Riley division between class I and class II radio sources has its origins in the coronae of magnetized accretion disks around black holes. The "magnetic switch", an effect that critically controls the speed of jets produced by such disks, can explain both qualitative and quantitative differences in the properties of the two classes. These include why morphology and jet speed are functions of radio power and why the division between the two classes is a strong function of galaxy optical luminosity. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 51 EP 52 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500014 ER PT B AU Murphy, DW Tingay, SJ Preston, RA Meier, DL Jones, DL Edwards, PG Costa, ME Lovell, JEJ McCulloch, PM Jauncey, DL Reynolds, JE Tzioumis, AK King, EA Nicolson, GD Quick, JFH Wan, TS Shen, ZQ AF Murphy, DW Tingay, SJ Preston, RA Meier, DL Jones, DL Edwards, PG Costa, ME Lovell, JEJ McCulloch, PM Jauncey, DL Reynolds, JE Tzioumis, AK King, EA Nicolson, GD Quick, JFH Wan, TS Shen, ZQ BE Zensus, JA Taylor, GB Wrobel, JM TI VLBI of southern EGRET identifications SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We have undertaken VLBI observations of 8 Southern Hemisphere EGRET radio sources. Using our data as well as data obtained from the literature we have examined the difference in radio properties between gamma-ray loud and gamma-ray quiet radio sources. In particular, we find no evidence that gamma-ray loud radio sources lie preferentially in sources with straight radio jets as has been suggested. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Murphy, DW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Tingay, Steven/B-5271-2013; King, Edward/A-1473-2012 OI King, Edward/0000-0002-6898-2130 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 55 EP 56 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500016 ER PT B AU Jones, DL Wehrle, AE AF Jones, DL Wehrle, AE BE Zensus, JA Taylor, GB Wrobel, JM TI Symmetric parsec-scale radio jets in NGC 4261 SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB VLBA observations of NGC4261 (3C 270) reveal highly symmetric radio structures at both 1.6 and 8.4 GHz. There is little evidence for free-free absorption in the inner few pc, despite the fact that HST imaging shows this galaxy to contain a nearly edge-on disk of gas and dust in its nucleus. However, at our highest resolution we find a narrow gap in emission just east of the radio core which we interpret as evidence for a small (sub-parsec) nearly edge-on accretion disk which is obscuring the base of the counterjet. The position angle of the pc-scale radio axis agrees with the position angle of the VLA-scale jets, which differs from the apparent rotation axis of the nuclear disk seen by HST. 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 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 63 EP 64 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500020 ER PT B AU Unwin, SC Wehrle, AE Xu, W Zook, AC Marscher, AP AF Unwin, SC Wehrle, AE Xu, W Zook, AC Marscher, AP BE Zensus, JA Taylor, GB Wrobel, JM TI Superluminal motion in the gamma-ray blazar 3C 279 SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB The blazar 3C 279 is one of the strongest extragalactic sources of gamma-rays, and is also one of the best studied superluminal radio sources. Definitive testing of models of the broad-band spectral energy distribution, especially in the X-ray and gamma-ray regions requires knowledge of the evolution of the spectrum with time. Within the context of the relativistic jet model, multi-wavelength monitoring of the parsec-scale radio jet is also required. We present here the first steps toward such a test, using extensive VLBI monitoring over a 13 year interval at 22 GHz, and gamma-ray observations between 1991 and 1996. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Unwin, SC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 8 Z9 8 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 69 EP 70 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500023 ER PT B AU Tingay, SJ Jauncey, DL Reynolds, JE Tzioumis, AK Preston, RA Jones, DL Murphy, DW Meier, DL Lovell, JEJ McCulloch, PM Costa, ME Nicolson, G Quick, JFH AF Tingay, SJ Jauncey, DL Reynolds, JE Tzioumis, AK Preston, RA Jones, DL Murphy, DW Meier, DL Lovell, JEJ McCulloch, PM Costa, ME Nicolson, G Quick, JFH BE Zensus, JA Taylor, GB Wrobel, JM TI The sub-parsec-scale structure and evolution of Centaurus A at 8.4 and 22.2 GHz SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We have been observing the sub-parsec-scale radio jet in the nucleus of Centaurus A, the closest active radio galaxy, at 8.4 GHz over the last 6 years with the SHEVE array and most recently with the VLBA at 8.4 and 22.2 GHz. In this paper we will review the results of these observations and give a brief summary of our interpretation, concentrating on the evolution of the sub-parsec-scale jet structure with time; subluminal component motions and rapid short timescale evolution. A full description of this work is soon to be published in a major journal article. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Tingay, SJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Tingay, Steven/B-5271-2013 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 87 EP 88 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500032 ER PT B AU Preston, RA Tingay, SJ Jones, DL Murphy, DW Meier, DL Jauncey, DL Reynolds, JE Tzioumis, AK Lovell, JEJ McCulloch, PM Costa, ME Nicolson, G AF Preston, RA Tingay, SJ Jones, DL Murphy, DW Meier, DL Jauncey, DL Reynolds, JE Tzioumis, AK Lovell, JEJ McCulloch, PM Costa, ME Nicolson, G BE Zensus, JA Taylor, GB Wrobel, JM TI The counterjet in the nucleus of Centaurus A SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We have observed the nucleus of Centaurus A with the VLBA and the SHEVE arrays, individually and in combination. In sensitive experiments at 8.4 GHz which use both arrays together we have detected components in a sub-parsec-scale counterjet. The counterjet is also seen in 2.3 and 22 GHz images. The nuclear region appears to be partially obscured by a free-free absorbing structure of about 1 pc in extent. The jet axis appears to lie at a 50 degrees-70 degrees angle to our line of sight. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Preston, RA (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RI Tingay, Steven/B-5271-2013 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 91 EP 92 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500034 ER PT B AU Altunin, V Beasley, A Ludke, E Alekseev, V Lipatov, B Dagkesamansky, R Kardashev, N Kovalenko, A Molotov, I Slysh, V Migenes, V AF Altunin, V Beasley, A Ludke, E Alekseev, V Lipatov, B Dagkesamansky, R Kardashev, N Kovalenko, A Molotov, I Slysh, V Migenes, V BE Zensus, JA Taylor, GB Wrobel, JM TI Low frequency (327 MHz) VLBI survey: First results SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB In this paper we report the first results of the 327 MHz VLBI survey which has been carried out in the last two years to select potential candidate sources for the future SVLBI missions and to search for directions of small scattering-"holes" in the interstellar scattering medium. During the three VLBI sessions conducted so far, we observed about 80 sources. Preliminary data analyzed from the first part of the survey shows that at least 17 out of 50 sources have compact components with a size smaller than 30 mas. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Altunin, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kovalenko, Anatoly/N-1591-2015; Dagkesamanskii, Rustam/N-2113-2015; Kardashev, Nikolai/O-6441-2015 NR 0 TC 0 Z9 0 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 141 EP 142 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500056 ER PT B AU Xu, W Wehrle, AE Marscher, AP AF Xu, W Wehrle, AE Marscher, AP BE Zensus, JA Taylor, GB Wrobel, JM TI VLBA monitoring of three gamma-ray bright blazars: AO 0235+164, 1633+382 (4C38.41), & 2230+114 (CTA 102) SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We have been monitoring gamma-ray blazars with the NRAO VLBA at 22 and 43 GHz since late 1993. We present results on three sources: AO 0235+164, 1633+382 (4C 38.41), and 2230+114 (CTA102). C1 CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. RP Xu, W (reprint author), CALTECH, Jet Prop Lab, IPAC, 100-22, Pasadena, CA 91125 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 175 EP 176 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500073 ER PT B AU Guirado, JC Reynolds, JE Lestrade, JF Preston, RA Jauncey, DL Jones, DL Tzioumis, AK Ferris, RH King, EA Lovell, JEJ McCulloch, PM Johnston, KJ Kingham, KA Martin, JO White, GL Jones, PA Arenou, F Froeschle, M Kovalevsky, J Martin, C Lindegren, L Soderhjelm, S AF Guirado, JC Reynolds, JE Lestrade, JF Preston, RA Jauncey, DL Jones, DL Tzioumis, AK Ferris, RH King, EA Lovell, JEJ McCulloch, PM Johnston, KJ Kingham, KA Martin, JO White, GL Jones, PA Arenou, F Froeschle, M Kovalevsky, J Martin, C Lindegren, L Soderhjelm, S BE Zensus, JA Taylor, GB Wrobel, JM TI Evidence of a low-mass companion to AB Doradus SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB From the combination of VLBI phase-referenced observations and Hipparcos satellite data, we have found evidence of a low-mass object orbiting the late-type star AB Doradus. The mass of the new object is near the hydrogen burning limit and will constitute a precise point for calibrating the low end of the main sequence. This represents the first detection of a low-mass stellar companion using the VLBI technique, which could become an important tool in future searches for planets and brown dwarfs orbiting other stars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Guirado, JC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI King, Edward/A-1473-2012; Arenou, Frederic/B-1846-2014 OI King, Edward/0000-0002-6898-2130; Arenou, Frederic/0000-0003-2837-3899 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 325 EP 326 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500141 ER PT B AU Jones, DL Weiler, KW Allen, RJ Desch, MM Erickson, WC Kaiser, ML Kassim, NE Kuiper, TBH Mahoney, MJ Marsh, KA Perley, RA Preston, RA Stone, RG AF Jones, DL Weiler, KW Allen, RJ Desch, MM Erickson, WC Kaiser, ML Kassim, NE Kuiper, TBH Mahoney, MJ Marsh, KA Perley, RA Preston, RA Stone, RG BE Zensus, JA Taylor, GB Wrobel, JM TI The astronomical low-frequency array (ALFA) SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB The ALFA mission is designed to map the entire sky at frequencies between approximately 0.3 and 30 MHz with angular resolution limited by interstellar and interplanetary scattering. Most of this region of the spectrum is inaccessible from the ground because of absorption and refraction by the Earth's ionosphere. A wide range of astrophysical questions concerning solar system, galactic, and extragalactic objects could be answered with high resolution images at low frequencies, where absorption effects and coherent emission processes become important and the synchrotron lifetimes of electrons are comparable to the age of the universe. 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 0 TC 4 Z9 4 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 393 EP 394 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500175 ER PT B AU Wietfeldt, R Smith, J Border, J Altunin, V Ryne, M Lewis, C Benson, J Claussen, M Romney, J Springett, J Webber, J King, E Reynolds, J Wilson, W Jauncey, D Ferris, R Harbison, P Jenkins, B Costa, M Ellingsen, S Knight, C AF Wietfeldt, R Smith, J Border, J Altunin, V Ryne, M Lewis, C Benson, J Claussen, M Romney, J Springett, J Webber, J King, E Reynolds, J Wilson, W Jauncey, D Ferris, R Harbison, P Jenkins, B Costa, M Ellingsen, S Knight, C BE Zensus, JA Taylor, GB Wrobel, JM TI Simulated space VLBI experiment using the Tidbinbilla 11-m DSN tracking station and SURFSAT and simulated satellites SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We describe a space VLBI experiment involving an earth-orbiting satellite (SURF-SAT) and simulated satellites, a space VLBI ground tracking station, an array of ground radio telescopes, and a space VLBI correlator. The purpose of this experiment was to provide as complete as possible an end-to-end simulation of space VLBI in preparation for the first space VLBI mission, VSOP, and in particular to test the most critical aspect of space VLBI, viz. the ability to generate a stable and accurate frequency standard (clock) for the orbiting VLBI element. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wietfeldt, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI King, Edward/A-1473-2012 OI King, Edward/0000-0002-6898-2130 NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 415 EP 416 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500186 ER PT B AU Meier, DL AF Meier, DL BE Zensus, JA Taylor, GB Wrobel, JM TI Operating a telescope larger than the earth: How to schedule the HALCA space VLBI mission SO RADIO EMISSION FROM GALACTIC AND EXTRAGALACTIC COMPACT SOURCES SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT IAU Colloquium 164 on Radio Emission from Galactic and Extragalactic Compact Sources CY APR 21-26, 1997 CL NEW MEXICO INST MIN & TECHNOL, MACEY CTR, SOCORRO, NM SP Int Astron Union, Commiss 28 Galaxies, Int Astron Union, Commiss 40 Radio Astron, Union Radio Sci Int, Commiss J Radio Astron, Associated Univ Inc HO NEW MEXICO INST MIN & TECHNOL, MACEY CTR AB We outline the HALCA Space VLBI mission scheduling process, with special emphasis placed on software that decides when to observe the proposed sources and how to ensure that the highest quality science is obtained. This information will be useful to the many principal investigators whose very high resolution VLBI observations are being supported by the mission. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Meier, DL (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 ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-64-3 J9 ASTR SOC P PY 1998 VL 144 BP 421 EP 422 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75N UT WOS:000076608500189 ER PT J AU Hajj, GA Romans, LJ AF Hajj, GA Romans, LJ TI Ionospheric electron density profiles obtained with the global positioning system: Results from the GPS/MET experiment SO RADIO SCIENCE LA English DT Article ID EARTHS ATMOSPHERE; RADIO AB The Global Positioning System Meteorology (GPS/MET) experiment, which placed a GPS receiver in a low-Earth orbit tracking GPS satellites setting behind the Earth's limb, has collected data from several thousands of occultations since its launch in April 1995. This experiment demonstrated for the first time the use of GPS in obtaining profiles of electron density and other geophysical variables such as temperature, pressure, and water vapor in the lower atmosphere. This paper discusses some of the effects of the ionosphere, such as bending and scintillation, on the GPS signal during occultation. It also presents a set of ionospheric profiles obtained from GPS/MET using the Abel inversion technique, and compares these profiles with ones obtained from the parameterized ionospheric model (PIM) and with ionosonde and incoherent scatter radar measurements. Statistical comparison of NmF2 values obtained from GPS/MET profiles and nearby ionosondes indicates that they agree to about similar to 20% (1-sigma) in a fractional sense. The high vertical resolution, characteristic of the occultation geometry, is reflected in the GPS/MET profiles which reveal ionospheric structures of very small vertical scales such as the sporadic E. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hajj, GA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 21 TC 239 Z9 262 U1 3 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN-FEB PY 1998 VL 33 IS 1 BP 175 EP 190 DI 10.1029/97RS03183 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA YX749 UT WOS:000072073400016 ER PT J AU Currie, LA Dibb, JE Klouda, GA Benner, BA Conny, JM Biegalski, SR Klinedinst, DB Cahoon, DR Hsu, NC AF Currie, LA Dibb, JE Klouda, GA Benner, BA Conny, JM Biegalski, SR Klinedinst, DB Cahoon, DR Hsu, NC TI The pursuit of isotopic and molecular fire tracers in the polar atmosphere and cryosphere SO RADIOCARBON LA English DT Article; Proceedings Paper CT 16th International Radiocarbon Conference CY JUN, 1997 CL GRONINGEN, NETHERLANDS SP Royal Netherlands Acad Sci, Groninger Universiteitsfonds ID GREENLAND; SUMMIT; SNOW AB We present an overview of recent multidisciplinary, multi-institutional efforts to identify and date major sources of combustion aerosol in the current and paleoatmospheres. The work was stimulated, in part, by an atmospheric particle "sample of opportunity" collected at Summit, Greenland in August 1994, that bore the C-14 imprint of biomass burning. During the summer field seasons of 1995 and 1996, we collected air filter, surface snow and snowpit samples to investigate chemical and isotopic evidence of combustion particles that had been transported from distant fires. Among the chemical tracers employed for source identification are organic acids, potassium and ammonium ions, and elemental and organic components of carbonaceous particles. Ion chromatography, performed by members of the Climate Change Research Center (University of New Hampshire), has been especially valuable in indicating periods at Summit that were likely to have been affected by the long range transport of biomass burning aerosol. Univariate and multivariate patterns of the ion concentrations in the snow and ice pinpointed surface and snowpit samples for the direct analysis of particulate (soot) carbon and carbon isotopes. The research at NIST is focusing on graphitic and polycyclic aromatic carbon, which serve as almost certain indicators of fire, and measurements of carbon isotopes, especially C-14 to distinguish fossil and biomass combustion sources. Complementing the chemical and isotopic record, are direct "visual" (satellite imagery) records and less direct backtrajectory records, to indicate geographic source regions and transport paths. In this paper we illustrate the unique way in which the synthesis of the chemical, isotopic, satellite and trajectory data enhances our ability to develop the recent history;of the formation and transport of soot deposited in the polar snow and ice. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Climate Change Res Ctr, Durham, NH 03824 USA. NASA, Langley Res Ctr, Radiat Sci Branch, Div Atmospher Sci, Hampton, VA 23681 USA. Hughes STX, Lanham, MD 20706 USA. RP Currie, LA (reprint author), NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Biegalski, Steven/A-7765-2010; Hsu, N. Christina/H-3420-2013 NR 19 TC 15 Z9 15 U1 0 U2 4 PU UNIV ARIZONA DEPT GEOSCIENCES PI TUCSON PA RADIOCARBON 4717 E FORT LOWELL RD, TUCSON, AZ 85712 USA SN 0033-8222 J9 RADIOCARBON JI Radiocarbon PY 1998 VL 40 IS 1 SI SI BP 381 EP 390 PN 1 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 113KT UT WOS:000075550700049 ER PT S AU Sengupta, DK Kim, S Kuo, HC Curtis, AP Hsieh, KC Bishop, SG Feng, M Stillman, GE Gunapala, SD Bandara, SV Chang, YC Liu, HC AF Sengupta, DK Kim, S Kuo, HC Curtis, AP Hsieh, KC Bishop, SG Feng, M Stillman, GE Gunapala, SD Bandara, SV Chang, YC Liu, HC BE Ozturk, MC Roozeboom, F Timans, PJ Pas, SH TI Bandgap shifting of an ultra-thin InGaAs/InP quantum well infrared photodetector via rapid thermal annealing SO RAPID THERMAL AND INTEGRATED PROCESSING VII SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Rapid Thermal and Integrated Processing at the MRS Spring Meeting CY APR 13-15, 1998 CL SAN FRANCISCO, CA SP Mat Res Soc AB We demonstrate that SiO2 cap rapid thermal annealing in ultra-thin p-type InGaAs/InP quantum wells can be used to produce large blue shifts of the band edge. A substantial bandgap blue shift, as much as 292.5 meV at 900 degrees C has been measured and the value of the bandgap shift can be controlled by the anneal time. Theoretical modeling of the intermixing effect on the energy levels is performed based on the effective bond-orbital method, and we obtain a very good fit to the photoluminescence data. Compared to the as-grown detector, the peak spectral response of the annealed detector was shifted to longer wavelength without any major degradation in the responsivity characteristics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sengupta, DK (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 MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-431-9 J9 MATER RES SOC SYMP P PY 1998 VL 525 BP 385 EP 390 PG 6 WC Engineering, Manufacturing; Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Engineering; Materials Science GA BL75B UT WOS:000076553400050 ER PT B AU Han, J AF Han, J BE Kadish, KM Ruoff, RS TI Identification of complex carbon nanotube structures SO RECENT ADVANCES IN THE CHEMISTRY AND PHYSICS OF FULLERENES AND RELATED MATERIALS, VOL 6 SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 6th Symposium of the Fullerenes Group on Fullerenes - Chemistry, Physics, and New Directions IX at the 193rd Meeting of the Electrochemical-Society CY MAY 03-08, 1998 CL SAN DIEGO, CA SP Electrochem Soc, Fullerenes Grp AB A variety of complex carbon nanotube (CNT) structures have been observed experimentally. These include sharp bends, branches, tori, and helices. They are believed to be formed by using topological defects such as pentagons and heptagons to connect different CNT. The effects of type, number, and arrangement (separation and orientation) of defects on atomic structures and enegetics of complex CNT are investigated using topology, quantum mechanics and molecular mechanics calculations. Energetically stable models are derived for identification of observed complex CNT structures. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Han, J (reprint author), NASA, Ames Res Ctr, T27A-1, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-202-8 J9 ELEC SOC S PY 1998 VL 98 IS 8 BP 875 EP 884 PG 4 WC Chemistry, Physical; Electrochemistry; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Physics, Atomic, Molecular & Chemical SC Chemistry; Electrochemistry; Materials Science; Physics GA BL68Q UT WOS:000076312100081 ER PT S AU Owe, M Van de Griend, AA de Jeu, R de Vries, J Seyhan, E AF Owe, M Van de Griend, AA de Jeu, R de Vries, J Seyhan, E BE Engman, ET TI Satellite microwave estimates of soil moisture and their application for desertification studies SO REMOTE SENSING FOR AGRICULTURE, ECOSYSTEMS, AND HYDROLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Remote Sensing for Agriculture, Ecosystems, and Hydrology CY SEP 22-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE satellite remote sensing; microwave; soil moisture; desertification; climate change ID VEGETATION OPTICAL DEPTH; SINGLE SCATTERING ALBEDO; SURFACE MOISTURE; WATER-CONTENT; EMISSION; POLARIZATION; MODEL; CANOPIES; BEHAVIOR; CLIMATE AB Based on a series of studies conducted in Botswana and preliminary results from an ongoing study in Spain, developments in microwave remote sensing by satellite which can be used to monitor near real-time surface moisture and also study long term soil moisture climatology are described A progression of methodologies beginning with single polarization studies and leading to both dual polarization and multiple frequency techniques are described Continuing analysis of a nine year data set of satellite-derived surface moisture in Spain is ongoing. Preliminary results from this study appear to provide some evidence of long term desertification in certain parts of this region. The methodologies developed during these investigations can be applied to other regions, and have the potential for providing modellers with extended data sets of independently derived surface moisture for simulation and validation studies, and climate change studies at the global scale. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Owe, M (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Mail Code 974, Greenbelt, MD 20771 USA. NR 22 TC 0 Z9 0 U1 2 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 0-8194-2958-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3499 BP 30 EP 40 DI 10.1117/12.332765 PG 11 WC Ecology; Remote Sensing; Optics; Water Resources SC Environmental Sciences & Ecology; Remote Sensing; Optics; Water Resources GA BM37Z UT WOS:000078534700004 ER PT S AU Smith, JA Ballard, JR Balick, LK Getter, JR AF Smith, JA Ballard, JR Balick, LK Getter, JR BE Engman, ET TI Effect of spatial resolution on thermal IR sensing of plant canopies SO REMOTE SENSING FOR AGRICULTURE, ECOSYSTEMS, AND HYDROLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Remote Sensing for Agriculture, Ecosystems, and Hydrology CY SEP 22-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE thermal infrared; near infrared; canopy model; brightness temperature; NDVI; spatial resolution ID SURFACE-TEMPERATURE; VEGETATION INDEX; AIR-TEMPERATURE; RADIANCE; COVER AB Satellite observations of agricultural and other plant canopies in the thermal IR regime have generally been at spatial scales of tens to hundreds of meters. Use of the thermal IR at higher resolutions is confounded by the mixture problem and other associated scaling issues. Advances in sensor technology will extend our capabilities for IR measurements to shorter wavelengths and yield improved spatial resolutions. However, experience with aircraft remote sensing observations has indicated that care must be exercised in understanding the interaction effects of viewing geometry at these higher resolutions. The utilization and scaling of observables with multi-resolution remote sensing data sets remain a difficult problem. At high spatial resolution the three-dimensional character of scene components contained within a pixel must be considered. In this paper, we explore the variability in brightness temperature and the co-variation of NDVI with brightness temperature as a function of viewing geometry and changing spatial resolution. Using three-dimensional models for both canopy reflectance and thermal IR exitance, we employ a theoretical analysis for an agricultural scene where previous comparisons and measurements were available. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, JA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 15 TC 0 Z9 0 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 0-8194-2958-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3499 BP 157 EP 162 DI 10.1117/12.332747 PG 6 WC Ecology; Remote Sensing; Optics; Water Resources SC Environmental Sciences & Ecology; Remote Sensing; Optics; Water Resources GA BM37Z UT WOS:000078534700018 ER PT S AU Kim, MS Chappelle, EW Leblanc, E Mulchi, CL Daughtry, CST McMurtrey, JE Rowland, RA AF Kim, MS Chappelle, EW Leblanc, E Mulchi, CL Daughtry, CST McMurtrey, JE Rowland, RA BE Engman, ET TI Assessment of combined effects of mild water stress, elevated tropospheric O-3, and CO2 on crops using fluorescence imaging SO REMOTE SENSING FOR AGRICULTURE, ECOSYSTEMS, AND HYDROLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Remote Sensing for Agriculture, Ecosystems, and Hydrology CY SEP 22-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE fluorescence; fluorescence imaging; air pollutants; O-3 stress; CO2; open-top chamber ID LASER-INDUCED FLUORESCENCE; GREEN PLANTS; ATMOSPHERIC CO2; CHLOROPHYLL FLUORESCENCE; NUTRIENT DEFICIENCIES; OZONE; CORN; LIF; REFLECTANCE; RADIATION AB As a part of the environmental air quality assessment studies, we have conducted spectral characterizations of steady state fluorescence and canopy level reflectance measurements in responses to the air quality treatments. These studies have been carried out under well watered and restricted soil moisture regimes. Our primary objective was to evaluate fluorescence technique for the nondestructive assessment of plants grown in elevated CO2, elevated O-3, and both elevated CO2 and O-3 environments under normal and restricted soil moisture conditions. The experimental field site is located at the South Farm, USDA/BARC, Beltsville, Maryland. We used field open-top chamber systems to simulate four altered combinations of tropospheric CO2 and O-3 environments under well watered and restricted soil moisture conditions. The simulated gaseous environments included: 1) charcoal-filtered (CF) ambient air as the control chamber; 2) elevated CO2 consisted of CF ambient air plus 150 +/- 10 mu l/l CO2; 3) elevated O-3 that consisted of Non-Filtered (NF) ambient air and addition of 35 +/- 5 nl/l O-3; and 4) high CO2 and O-3 chamber which consisted of NF ambient and additions of 150 +/- 10 mu l/l CO2 and 35 +/- 5 nl/l O-3. The CO2 was supplied for 18 hours (3:00 to 21:00 h EST) per day from a CO2 bulk tank. In the elevated O-3 treatment chambers, 35 +/- 5 nl/l O-3 was supplied during seven hour period from 9:00 to 16:00 h EST per day. Both gases were supplied for the entire growing season from early July to late-October. Two soybean cultivars 'Essex' and 'Forrest' were planted in the OTC. Fluorescence images were acquired at F450, F550, F680, and F740. The results showed that fluorescence responses of 'Essex' and 'Forrest' were significantly different in all four bands. Restricted soil moisture treatment had significant effects in that means for F450 and F550 bands significantly increased in both cultivars. The increases in fluorescence intensities at F450 and F550 for 'Essex' due to restricted soil moisture were much greater than those of 'Forrest'. At F680 and F740 bands, only 'Essex' was significantly affected by soil moisture treatment. The most significant effects of elevated CO2 and O-3 were observed at F450 and F550 bands. Means for elevated O-3 in ambient air in both cultivars were significantly higher in both soil moisture regimes. However, no significant differences between CF and NF+CO2+O-3 within a soil moisture treatment were observed. Means for CF+CO2 was significantly lower for both cultivars under well watered soil condition at F450. In general, none of the treatment means were significantly affected by elevated O-3 treatments at F680 and F740. Although visible stress symptoms such as chlorosis, discoloration, or necrosis were not evident in the leaves used in this study, F450 and F550 fluorescence images depicted the effects of elevated O-3, partial compensation of elevated O-3 effects by the elevated CO2, and positive physiological effects of elevated CO2. Plant stresses that cause localized damage may not be easily detected with small field of view point measurements. Imaging a whole leaf may provide better means to study the effects of non-systemic stresses. We are also currently investigating reflectance techniques for a possible complementary use with fluorescence measurements in the remote assessment of above treatment effects. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Kim, MS (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NR 27 TC 1 Z9 1 U1 1 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 0-8194-2958-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3499 BP 286 EP 294 DI 10.1117/12.332761 PG 9 WC Ecology; Remote Sensing; Optics; Water Resources SC Environmental Sciences & Ecology; Remote Sensing; Optics; Water Resources GA BM37Z UT WOS:000078534700031 ER PT S AU Levine, E Kurz, L Smid, J Smid, M Volf, P AF Levine, E Kurz, L Smid, J Smid, M Volf, P BE Engman, ET TI Algorithms and analysis tools for carbon content modeling in soil based on satellite data SO REMOTE SENSING FOR AGRICULTURE, ECOSYSTEMS, AND HYDROLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Remote Sensing for Agriculture, Ecosystems, and Hydrology CY SEP 22-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE soil carbon; remote sensing; statistical analysis; classification; functional models (regression) AB Estimate of the organic carbon content in soil is critical for global change modeling activities. Therefore, the predictive model for estimating soil carbon would provide an important tool for the scientific community. We used remotely sensed TM imaginery data together with the soil profiles and moss layer carbon data for the Northern Study Area (NSA) of the BOREAS project. Different classification and functional models of the carbon dependency on remotely sensed data were developed. The complexity of the models was scrutinized. Based on these techniques, we have developed a set of analysis tools. These tools and an Internet based access to some of these tools will be presented. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20770 USA. RP Levine, E (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20770 USA. NR 8 TC 0 Z9 0 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 0-8194-2958-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3499 BP 315 EP 322 DI 10.1117/12.332764 PG 8 WC Ecology; Remote Sensing; Optics; Water Resources SC Environmental Sciences & Ecology; Remote Sensing; Optics; Water Resources GA BM37Z UT WOS:000078534700034 ER PT S AU Susskind, J Barnet, C Blaisdell, J AF Susskind, J Barnet, C Blaisdell, J BE Susskind, J Singhroy, V Tanaka, S TI Determination of atmospheric and surface parameters from simulated AIRS/AMSU/HSB sounding data: Retrieval and cloud clearing methodology SO REMOTE SENSING: INVERSION PROBLEMS AND NATURAL HAZARDS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs AB New state of the art methodology is described to analyze 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 ATRS/AMSU/HSB data on EOS PM1. 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 does not require modelling or knowledge of the first guess error characteristics. Results are shown for AIRS Science Team simulation studies with multiple cloud formations. These simulation studies imply that temperature soundings can be produced under partial cloud cover with RMS errors better than 1 degrees K in 1 km thick layers from the surface to 700 mb, 1 km layers from 700 mb to 300 mb, 3 km layers from 300 mb to 30 mb, and 5 km layers from 30 mb to 1 mb, and moisture profiles can be obtained with an accuracy of about 10% absolute errors in 1 km layers from the surface to 200 mb. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Goddard Space Flight Ctr, Gen Sci Corp, Greenbelt, MD 20771 USA. RP Susskind, J (reprint author), NASA, Goddard Space Flight Ctr, Gen Sci Corp, Code 910-4, Greenbelt, MD 20771 USA. RI Barnet, Christopher/F-5573-2010 NR 5 TC 17 Z9 20 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043311-1 J9 ADV SPACE RES PY 1998 VL 21 IS 3 BP 369 EP 384 DI 10.1016/S0273-1177(97)00916-2 PG 16 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BK82U UT WOS:000073538000002 ER PT S AU Dubovik, O Yokota, T Sasano, Y AF Dubovik, O Yokota, T Sasano, Y BE Susskind, J Singhroy, V Tanaka, S TI Improved technique for data inversion and its application to the retrieval algorithm for ADEOS/ILAS SO REMOTE SENSING: INVERSION PROBLEMS AND NATURAL HAZARDS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs ID TEMPERATURE AB An improved numerical inversion scheme is discussed. The way the scheme is formulated allows one to include the iterative stabilization of inversion by solving constrained least square system using linear iterations. Therefore, the technique discussed is closely related to both matrix inversion and iterative inversion methods, which are often considered as alternative to each other. As a result, this inversion procedure provides both a statistically optimum and highly stable solution even in the case of a very large number of unknowns. Also, various a priori information can be used: non-negativity of solution (by logarithmic transformation), smoothness of retrieved characteristics, a priori estimations of solution, etc. The proposed technique is applied to provide statistical optimization of the retrieval algorithm for the Improved Limb Atmospheric Spectrometer (ILAS) aboard the Advanced Earth Observing Satellite (ADEOS). ILAS has 1024 visible channels and 44 IR channels to measure atmospheric transmittance at different atmospheric levels. More than 400 parameters (temperature, pressure, gas and aerosol profiles) should be determined from ILAS data. To realize statistical optimization for such a situation is quite a challenging problem. The main advantages and difficulties of applying this inversion technique for this optimization are discussed. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 Natl Inst Environm Studies, Global Environm Div, Tsukuba, Ibaraki 305, Japan. RP Dubovik, O (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 923, Greenbelt, MD 20771 USA. RI Dubovik, Oleg/A-8235-2009; Sasano, Yasuhiro/C-2927-2009 OI Dubovik, Oleg/0000-0003-3482-6460; Sasano, Yasuhiro/0000-0001-7470-5642 NR 14 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043311-1 J9 ADV SPACE RES PY 1998 VL 21 IS 3 BP 397 EP 403 DI 10.1016/S0273-1177(97)00920-4 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BK82U UT WOS:000073538000006 ER PT S AU Okamoto, H Sasano, Y Mukai, S Sano, I Ishihara, H Matsumoto, T Thomason, L Pitts, M AF Okamoto, H Sasano, Y Mukai, S Sano, I Ishihara, H Matsumoto, T Thomason, L Pitts, M BE Susskind, J Singhroy, V Tanaka, S TI ADEOS/ILAS aerosol retrieval algorithm with 5 channels SO REMOTE SENSING: INVERSION PROBLEMS AND NATURAL HAZARDS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, World Climate Res Programme, European Space Agcy, NOAA, Natl Environm Satellite Data & Informat Sci, Sci Comm Ocean Res, Int Union Geol Sci, Int Astronaut Federat, Int Decade Nat Disaster Reduct, UNESCO, UN, Off Outer Space Affairs ID POLAR AB The information content of aerosol properties is discussed for a set of extinction coefficient measurements of the ILAS (Improved Limb Atmospheric Spectrometer) instrument. ILAS was launched on the ADEOS (Advanced Earth Observing Satellite) spacecraft in 1996 and has a wine spectral coverage in the infrared region (between 6.21 and 11.77 mu m). From these extinction measurements: ILAS has a capability to provide the vertical profiles of gaseous species, which are important for studies of the ozone hole phenomena, as well as the stratospheric aerosol compositions. In this paper, we describe an algorithm to infer the chemical composition of aerosols: i.e.: types of PSCs (polar stratospheric clouds), the size distributions, total volume and total surface areas of aerosols by using five window channels, i.e. one at visible wavelength (0.78 mu m) and four (7.12, 8.27: 10.60, 11.76 mu m) at infrared wavelengths. Our algorithm mainly consists of two parts. The first part is to determine the chemical composition of PSCs and sulfate aerosols, The second one is to derive the mean size, volume and surface area. The main purpose of this paper are to provide the extinction spectrum over the whole: infrared channels in older to estimate the reliable amounts of trace gases and also to estimate the information of aerosol surface distribution for heterogeneous chemical reaction studies on PSCs. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 Univ Tokyo, Ctr Climate Syst Res, Meguro Ku, Tokyo 153, Japan. Natl Inst Environm Studies, Tsukuba, Ibaraki 305, Japan. Kinki Univ, Higashiosaka, Osaka 577, Japan. Fujitsu FACOM Informat Proc Corp, Shibuya Ku, Tokyo 150, Japan. Nasa Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. RP Okamoto, H (reprint author), Univ Tokyo, Ctr Climate Syst Res, Meguro Ku, 4-6-1 Komaba, Tokyo 153, Japan. RI Sasano, Yasuhiro/C-2927-2009; Okamoto, Hajime/E-6510-2010; OI Sasano, Yasuhiro/0000-0001-7470-5642; Okamoto, Hajime/0000-0002-4540-1698; Thomason, Larry/0000-0002-1902-0840 NR 9 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043311-1 J9 ADV SPACE RES PY 1998 VL 21 IS 3 BP 443 EP 446 DI 10.1016/S0273-1177(97)00927-7 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BK82U UT WOS:000073538000014 ER PT J AU Chen, G Chapron, B Tournadre, J Katsaros, K Vandemark, D AF Chen, G Chapron, B Tournadre, J Katsaros, K Vandemark, D TI Identification of possible wave damping by rain using TOPEX and TMR data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SYNTHETIC-APERTURE RADAR; SEA; ATTENUATION; FOOTPRINTS; SCATTERING AB A global picture of wave damping by rain (WDBR), a phenomenon familiar to seafarers for centuries, has been so far unavailable owing to the fact that neither rules nor tools exist for its systematic measurement. The situation has changed following the launch of the first dual-frequency (5.3 GHz and 13.6 GHz) radar altimeter TOPEX, along with the three-frequency (18 GHz, 21 GHz, and 37 GHz) radiometer TMR (TOPEX Microwave Radiometer). In this study, a scheme for detecting possible WDBR using TOPEX/TMR data is proposed. The geographical distribution of identified WDBR is consistent with the simultaneous presence of high sea state and intensive rainfall. Frequent occurrences of WDBR are observed in the midlatitude of the two hemispheres, particularly in the Pacific Ocean. In contrast, WDBR rarely occurs in the majority of the tropical and subtropical oceans. The global seasonality of WDBR is found to be weak as a result of the hemispheric phase opposition of sea state and rainfall in their annual variations. Knowledge of spatial distribution and temporal variation of WDBR is useful in dealing with potential systematic biases in satellite wind and wave measurements due to rain/sea interaction. It would have been interesting to compare the WDBR with coincident estimates of global rainfall from the SSM/I (Special Sensor Microwave/Imager). (C) Elsevier Science Inc., 1998. C1 IFREMER, CTR BREST, DEPT OCEANOG SPATIALE, F-29280 PLOUZANE, FRANCE. NASA, GODDARD SPACE FLIGHT CTR, WALLOPS FLIGHT FACIL, LAB HYDROSPHER PROC, CODE 972, WALLOPS ISL, VA 23337 USA. RP Chen, G (reprint author), OCEAN UNIV QINGDAO, OCEAN REMOTE SENSING INST, 5 YUSHAN RD, QINGDAO 266003, PEOPLES R CHINA. RI Chapron, Bertrand/O-6527-2015; tournadre, jean/F-8402-2010 OI tournadre, jean/0000-0003-1159-4388 NR 18 TC 7 Z9 8 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN PY 1998 VL 63 IS 1 BP 40 EP 48 DI 10.1016/S0034-4257(97)00115-6 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA YJ333 UT WOS:A1998YJ33300004 ER PT J AU Carter, GA AF Carter, GA TI Reflectance wavebands and indices for remote estimation of photosynthesis and stomatal conductance in pine canopies SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID DIFFERENCE VEGETATION INDEX; LEAF SPECTRAL REFLECTANCE; RED EDGE POSITION; CHLOROPHYLL CONTENT; PLANT STRESS; FOREST-DECLINE; LEAVES; TRANSPIRATION; NITROGEN; EVAPOTRANSPIRATION AB A field experiment determined the reflectance wavebands and indices which corresponded most strongly with photosynthetic capacity in a mixed stand of loblolly pine (Pinus taeda L.) and slash pine (P. elliottii Engelm. var. elliottii). The 5-year-old pines ranged in height from 3 m to 6 m and formed an optically dense canopy. Variation in photosynthetic capacity was amplified by soil application of photosystem II herbicides diuron and bromacil to three of six experimental plots. Field measurements began on 23 August 1994 and continued through 20 December 1994. Canopy reflectance and leaf physiological data were acquired during mid to late morning for the sides of trees that generally received full sunlight. Net CO2 assimilation rate first regressed significantly with reflectance on 5 October at wavelengths near 700 nm. In the 5 October to 2 December period, assimilation rates approximated photosynthetic capacity. When data were combined over this period, the ration of reflectance at 701+/-2 nm with reflectance at 520+/-2 nm, or a normalized difference vegetation index (NDVI) computed from these values, regressed more strongly with photosynthetic capacity than first derivatives of spectral reflectance or wavelength at the read edge inflection point. The narrow band NDVI accounted for 17-29% more variability in the data than NDVI that were based on simulated TM, MSS, AVHRR, or SPOT bands. As a result of its linear relationship with assimilation rate, stomatal conductance to water vapor also regressed strongly with the narrow band ratio. These results are explained by the high sensitivity of reflectance near 700 nm to leaf chlorophyll content. The use of a narrow band centered near 700 nm along with a narrow or broad near infrared band in vegetation indices should provide increased accuracy in estimates of photosynthetic capacity and corresponding conductance for optically dense canopies. Evaluation of the influence of leaf area index on these relationships will require further study. Published by Elsevier Science Inc., 1998. RP Carter, GA (reprint author), NASA,EARTH SYST SCI OFF,STENNIS SPACE CTR,MS 39529, USA. NR 54 TC 84 Z9 96 U1 7 U2 18 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JAN PY 1998 VL 63 IS 1 BP 61 EP 72 DI 10.1016/S0034-4257(97)00110-7 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA YJ333 UT WOS:A1998YJ33300006 ER PT B AU Green, WB Jensen, D Culver, A AF Green, WB Jensen, D Culver, A BE Thompson, DO Chimenti, DE TI Digital processing of remotely sensed imagery SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Green, WB (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 PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 23 EP 31 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500003 ER PT B AU Namkung, M Wincheski, B Fulton, JP Nath, S AF Namkung, M Wincheski, B Fulton, JP Nath, S BE Thompson, DO Chimenti, DE TI Theoretical aspects of transient electromagnetic field in finite sized conducting media SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Namkung, M (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Namkung, Min/E-1533-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 267 EP 274 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500034 ER PT B AU Wincheski, B Namkung, M AF Wincheski, B Namkung, M BE Thompson, DO Chimenti, DE TI Detection of sublayer fatigue cracks under airframe rivets SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Wincheski, B (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Namkung, Min/E-1533-2012 NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 331 EP 338 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500042 ER PT B AU Cramer, KE Winfree, WP AF Cramer, KE Winfree, WP BE Thompson, DO Chimenti, DE TI Thermographic characterization of corrosion using a scanned thermal line source SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cramer, KE (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 431 EP 439 PG 9 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500055 ER PT B AU Winfree, WP AF Winfree, WP BE Thompson, DO Chimenti, DE TI Enhanced thermographic detection of delaminations with computational pulse shaping SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winfree, WP (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 441 EP 447 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500056 ER PT B AU Plotnikov, YA Winfree, WP AF Plotnikov, YA Winfree, WP BE Thompson, DO Chimenti, DE TI Thermographic imaging of defects in anisotropic composites SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Plotnikov, YA (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 457 EP 464 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500059 ER PT B AU Bar-Cohen, Y Lih, SS Mal, A Chang, ZS AF Bar-Cohen, Y Lih, SS Mal, A Chang, ZS BE Thompson, DO Chimenti, DE TI Rapid characterization of the degradation of composites using plate waves dispersion data SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (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 PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 1171 EP 1176 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500151 ER PT B AU Madaras, EI Winfree, WP Johnston, PH AF Madaras, EI Winfree, WP Johnston, PH BE Thompson, DO Chimenti, DE TI Ultrasonic studies of composites undergoing thermal and fatigue loading SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Madaras, EI (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 1237 EP 1244 PG 8 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500160 ER PT B AU Yost, WT Cantrell, JH Gates, TS Whitley, KS AF Yost, WT Cantrell, JH Gates, TS Whitley, KS BE Thompson, DO Chimenti, DE TI Effects of molecular weight on mechanical properties of the polyimide LaRC-SI (TM) SO REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 17A AND 17B LA English DT Proceedings Paper CT Annual Review of Progress in Quantitative Nondestructive Evaluation CY JUL 27-AUG 01, 1997 CL SAN DIEGO, CA SP Iowa State Univ, Ctr NDE, US DOE, Ames Lab, Amer Soc Nondestruct Testing, Natl Inst Stand & Technol, FAA, Natl Sci Fdn Ind, Univ Cooperat Res Ctr C1 NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. RP Yost, WT (reprint author), NASA, Langley Res Ctr, Div Mat, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA BN 0-306-45901-9 PY 1998 BP 1411 EP 1417 PG 7 WC Engineering, Electrical & Electronic; Engineering, Mechanical; Materials Science, Ceramics; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Materials Science, Composites SC Engineering; Materials Science GA BL11N UT WOS:000074324500182 ER PT J AU Schramm, DN Turner, MS AF Schramm, DN Turner, MS TI Big-bang nucleosynthesis enters the precision era SO REVIEWS OF MODERN PHYSICS LA English DT Review ID RED GIANT STARS; DEUTERIUM ABUNDANCE; PRIMORDIAL NUCLEOSYNTHESIS; HIGH-REDSHIFT; BARYON DENSITY; DARK-MATTER; HALO DWARFS; LITHIUM; HE-3; CONSTRAINTS AB The last parameter of big-bang nucleosynthesis, the density of ordinary matter (baryons), is being pinned down by measurements of the deuterium abundance in high-redshift hydrogen clouds. When it is,the primeval abundances of the light elements D, He-3, Li-7, and He-4 will be fixed. The first three will then become "tracers" in the study of Galactic and stellar chemical evolution. A precision determination of the He-4 abundance will allow an important consistency test of big-bang nucleosynthesis and will sharpen nucleosynthesis as a probe of fundamental physics, e.g., the bound to the number of light neutrino species. An independent consistency test is on the horizon: a high-precision determination of the baryon density from measurements of the fluctuations of the cosmic background radiation temperature. C1 Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. NR 110 TC 268 Z9 269 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD JAN PY 1998 VL 70 IS 1 BP 303 EP 318 DI 10.1103/RevModPhys.70.303 PG 16 WC Physics, Multidisciplinary SC Physics GA YU637 UT WOS:000071738700009 ER PT S AU Seraji, H AF Seraji, H BE Guglielmi, M TI A new class of nonlinear PID controllers SO ROBOT CONTROL 1997, VOLS 1 AND 2 SE IFAC SYMPOSIA SERIES LA English DT Proceedings Paper CT 5th IFAC Symposium on Robot Control 1997 (SYROCO 97) CY SEP 03-05, 1997 CL NANTES, FRANCE SP Int Federat Automat Control, Int Federat Informat Proc, Int Assoc Math & Comp Simulat, Tech Comm Robot, IEEE, Robot & Automat Soc, Inst Rech Cybernet Nantes, Ecole Cent Nantes, INRIA Rhone Alpes, Mairie Nantes, Min Natl Educ Res & Technol, France, CEREM, Adv Syst, ATLANTECH, DGA AB This paper introduces a new class of simple nonlinear PID-type controllers comprised of a sector-bounded nonlinear gain in cascade with a linear fixed-gain P, PD, PI, or PID controller. Two simple nonlinear gains are proposed: the sigmoidal function and the hyperbolic function. The systems to be controlled are assumed to be modeled or approximated by second-order transfer-functions, which can represent many robotic applications. The stability of the closed-loop systems incorporating nonlinear P, PD, PI, and PID controllers are investigated using the Popov Stability Criterion. A numerical example is given for illustration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Seraji, 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 PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0962-9505 BN 0-08-043026-0 J9 IFAC SYMP SERIES PY 1998 BP 65 EP 71 PG 3 WC Automation & Control Systems SC Automation & Control Systems GA BL38K UT WOS:000075339700010 ER PT S AU Fijany, A Djouani, K Fried, G Pontnau, J AF Fijany, A Djouani, K Fried, G Pontnau, J BE Guglielmi, M TI New factorization techniques and fast serial and parallel algorithms for operational space control of robot manipulators SO ROBOT CONTROL 1997, VOLS 1 AND 2 SE IFAC SYMPOSIA SERIES LA English DT Proceedings Paper CT 5th IFAC Symposium on Robot Control 1997 (SYROCO 97) CY SEP 03-05, 1997 CL NANTES, FRANCE SP Int Federat Automat Control, Int Federat Informat Proc, Int Assoc Math & Comp Simulat, Tech Comm Robot, IEEE, Robot & Automat Soc, Inst Rech Cybernet Nantes, Ecole Cent Nantes, INRIA Rhone Alpes, Mairie Nantes, Min Natl Educ Res & Technol, France, CEREM, Adv Syst, ATLANTECH, DGA DE robot dynamics and control; operational space control; parallel computation AB In this paper a new factorization technique for computation of inverse of mass matrix, M-1, and the operational space mass matrix, Lambda, as arising in implementation of the operational space control scheme, is presented. This technique results in Schur Complement factorization of both M-1 and Lambda and subsequently new O(N) algorithms for their computation. These O(N) algorithms are highly efficient for parallel computation. To our knowledge, they represent the first algorithms that can be fully parallelized, resulting in both time- and processor-optimal parallel algorithms. Using these algorithms, the OSC scheme can be implemented with an optimal efficiency in both serial and parallel environment. However, in addition to computational efficiency, these algorithms provides a deeper physical insight into the structure of computation which can be exploited for a better design of task space control schemes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fijany, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Djouani, Karim/F-6476-2012 OI Djouani, Karim/0000-0001-6060-8200 NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0962-9505 BN 0-08-043026-0 J9 IFAC SYMP SERIES PY 1998 BP 767 EP 774 PG 4 WC Automation & Control Systems SC Automation & Control Systems GA BL38K UT WOS:000075339700114 ER PT S AU Coronado, PL Stetina, F Jacob, D AF Coronado, PL Stetina, F Jacob, D BE Gerhart, GR TI New technologies to support NASA's mission to planet earth satellite remote sensing product validation: The use of an Unmanned Autopiloted Vehicle (UAV) as a platform to conduct remote sensing SO ROBOTIC AND SEMI-ROBOTIC GROUND VEHICLE TECHNOLOGY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Robotic and Semi-Robotic Ground Vehicle Technology CY APR 15-16, 1998 CL ORLANDO, FL SP Int Soc Optical Engn AB As part of the United States Global Change program, NASA has initiated its' Mission to Planet Earth Program (MTPE) which requires continuous global satellite measurements over an extended 15 year period. Various US and International Earth Observing Satellites will be launched during this period. To ensure continuity of the measurements, a significant instrument calibration and product validation effort is required and is planned as part of this program. However, the validation of satellite products requires extensive ground truthing which is both costly and time consuming and in many cases limited to specific calibration/validation areas. Thus there is a need to extend this validation effort to include more participants and provide new, more cost effective technologies to support the validation effort. The use of Unmanned Autopiloted Vehicles (UAV) and new miniature high performance instruments have been identified as providing this needed additional capability. This paper discusses the development sf a UAV, associated avionics and preliminary remote sensing instruments to support the extension of ground truthing and product validation of NASA's MTPE Programs, specifically, Earth Observing System (EOS). The UAV being described is based on thrust vectoring capabilities and a single-axis pivoted wing or "Freewing" design. This unique UAV system is illustrated along with the proposed autonomous avionics and preliminary remote sensing payloads. C1 NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Coronado, PL (reprint author), NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 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 0-8194-2815-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3366 BP 38 EP 49 DI 10.1117/12.317561 PG 12 WC Automation & Control Systems; Optics SC Automation & Control Systems; Optics GA BL60V UT WOS:000075999400005 ER PT B AU Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, J Smith, J AF Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, J Smith, J BE Demsetz, LA Bryne, RH Wetzel, JP TI Flexible, low-mass robotic arm actuated by electroactive polymers and operated equivalently to human arm and hand SO ROBOTICS 98 LA English DT Proceedings Paper CT 3rd ASCE Speciality Conference on Robotics for Challenging Environments (Robotics 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, NASA, Natl Aeronaut Soc, Amer Astronaut Soc, Amer Inst Architects, Sandia Natl Labs, Bechtel Corp, Fluor Daniel Corp AB Actuation devices are used for many space applications and there is increasing need to reduce their size, mass, cost and power consumption. To address this need, JPL is developing electroactive polymers (EAP) with emphasis on two EAP categories that induce large bending and longitudinal actuation strains. Comparison between EAP and the widely used transducing actuators shows that, while lagging in force delivering capability, these materials are superior in mass, power consumption and actuation strain levels. This study is concentrating on the development of effective EAPs and the enabling of mechanisms that employ their unique characteristics. Several EAP driven mechanisms that emulate human hand were developed including a gripper, manipulator arm and surface wiper. The manipulator arm is made of a composite rod that is lifted by a longitudinal rope actuator and has an end-effector gripper with bending EAP fingers allowing to grab and hold such objects as rocks. The EAP surface wiper operates like a human finger and can be used to remove dust from windows and solar cells. These EAP driven devices take advantage of the large displacement capability with less concern for their limited force actuation capability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 5 TC 2 Z9 2 U1 0 U2 2 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0337-6 PY 1998 BP 15 EP 21 PG 3 WC Automation & Control Systems; Engineering, Civil SC Automation & Control Systems; Engineering GA BM53M UT WOS:000079075400003 ER PT B AU McDanels, SJ AF McDanels, SJ BE Alman, DE Hawk, JA Simmons, JW TI Failure analysis of launch pad tubing from the Kennedy Space Center SO ROLL OF CHARACTERIZATION IN UNDERSTANDING ENVIRONMENTAL DEGRADATION OF MATERIALS SE MICROSTRUCTURAL SCIENCE LA English DT Proceedings Paper CT 30th Annual Technical Meeting of the International-Metallographic-Society CY JUL 20-23, 1997 CL SEATTLE, WA SP Int Met Soc AB NASA's Kennedy Space Center (KSC) and the Air Force's Cape Canaveral Air Station serve as the launch site for the vast majority of the private and government expendable space launch vehicles, as well as all shuttle flights. The launch effluent and residue from the Solid Rocket Boosters (SRBs) react with moisture to form hydrochloric acid. The generation of hydrochloric acid, coupled with the naturally corrosive marine environment at KSC and the severe mechanical loads imparted during lift-off, combine to create one of the harshest and most aggressive environments that hardware could encounter. Failure analyses were performed on 304 stainless steel tubing removed from the Launch Complex 39B (LC-39B) Gaseous Nitrogen (GN(2)) System, the Gaseous Oxygen (GO(2)) System, and the Breathing Air (B/A) Line; the tubing ruptured during normal service. Hydrostatic testing indicated a burst strength of 13,500 psi for the intact sections of tubing. Scanning electron microscopy (SEM) and metallographic examination revealed that the tubing failed due to corrosion pitting exacerbated by stress corrosion cracking (SCC). The pitting originated on the outer surface of the tube and ranged from superficial to severe, with some pits extending through 75 percent of the tube's wall thickness. The SCC emanated from the pits and further reduced the service strength of the component until it could no longer sustain the operating pressure and final catastrophic fracture occurred. Protective coatings to abate corrosive attack have helped preclude subsequent similar failures. PADS 39A AND 39B ARE used to launch space shuttle flights from the Kennedy Space Center (KSC). The pads are subjected to a very aggressive service environment. The proximity of KSC to the ocean creates a severely corrosive marine atmosphere. The launch effluent and residue from the SRB's react with moisture to generate hydrochloric acid. The aggressive environment, coupled with the tremendous mechanical loads imparted during lift-off, demand careful materials selection and protection to preclude premature failure of flight-critical components. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP McDanels, SJ (reprint author), NASA, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 2 Z9 2 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA 9503 KINSMAN RD, MATERIALS PARK, OH 44073 USA BN 0-87170-658-X J9 MICROSTR SC PY 1998 VL 25 BP 125 EP 129 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA BL08V UT WOS:000074227900015 ER PT B AU Kay, H AF Kay, H BE Patton, RJ Chen, J TI Robust identification using semiquantitative methods SO (SAFEPROCESS'97): FAULT DETECTION, SUPERVISION AND SAFETY FOR TECHNICAL PROCESSES 1997, VOLS 1-3 LA English DT Proceedings Paper CT 3rd IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes 1997 (SAFEPROCESS 97) CY AUG 26-28, 1997 CL KINGSTON HULL, ENGLAND SP Int Federat Automat Control, IFAC Tech Comm Fault Detect Safety & Supervis Tech Proc, IFAC Tech Comm Algorithms & Architectures Real Time Control, IFAC Tech Comm AI Real TIme Control, IFAC Tech Comm Chem Proc Control, IFAC Tech Comm Marine Syst, IFAC Tech Comm Components & Instruments, IFAC Tech Comm Aerosp, IFAC Tech Comm Automot Control, IFAC Tech Comm Transport Syst, IFAC Tech Comm Intelligent Autonomous Vehicles, IFAC Tech Comm Safety Comp Control Syst, IFAC Tech Comm Social Impact Automat, Univ Hull, Dept Electr Engn, UK Automat Control Council DE system identification; monitoring; diagnosis; qualitative simulation; numerical simulation AB While model-based process monitoring and system identification share the common goal of describing the behavior of a physical system based on a mathematical model, the assumptions made by system identification are typically too strong to apply it directly to monitoring problems. This article describes SQUID, a new system identification method that uses refutation rather than search to identify a model of a physical system. By ruling out implausible models rather than searching for the best model that fits the data, SQUID is more robust in the face of uninformative data and structural model uncertainty than are traditional identification methods. C1 NASA, Ames Res Ctr, Caelum Res, Moffett Field, CA 94035 USA. RP Kay, H (reprint author), NASA, Ames Res Ctr, Caelum Res, Moffett Field, CA 94035 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND BN 0-08-042381-7 PY 1998 BP 277 EP 282 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA BM87E UT WOS:000079972000042 ER PT S AU Cairns, B Travis, LD Russell, EE AF Cairns, B Travis, LD Russell, EE BE Haigh, JD TI An analysis of polarization: Ground-based upward looking and aircraft/satellite based downward looking measurements SO SATELLITE REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Satellite Remote Sensing of Clouds and the Atmosphere II CY SEP 23-25, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE surface properties; atmospheric correction; polarization; aerosols AB It is shown that it is possible to retrieve aerosol properties using polarization measurements from satellite, or aircraft even when the surface polarization is significant and unknown. This extends the domain for which it is possible to intercompare ground and aircraft/satellite estimates of aerosol properties and allows the retrieval of aerosol properties to be made above bare soil surfaces. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Cairns, B (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 0 TC 1 Z9 1 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 0-8194-2652-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3220 BP 103 EP 114 PG 12 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BK46E UT WOS:000072275500012 ER PT S AU Nolt, IG Ade, PAR Carli, B Evans, F Marshall, BT Mlynczak, MG Park, K Russell, JM AF Nolt, IG Ade, PAR Carli, B Evans, F Marshall, BT Mlynczak, MG Park, K Russell, JM BE Haigh, JD TI Far infrared remote sensing of cirrus cloud properties SO SATELLITE REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Satellite Remote Sensing of Clouds and the Atmosphere II CY SEP 23-25, 1997 CL LONDON, ENGLAND SP CNR, NASA, European Opt Soc, Soc Photo Opt Instrumentat Engineers, Commiss European Communities, Directorate Gen Sci Res & Dev DE cirrus; clouds; far IR; remote sensing; FTS spectroscopy AB The lack of a global cirrus cloud database is a major deficiency in validating Global Circulation Models which are the basis for estimating long term climate change. Cirrus clouds being composed of ice particles act to reflect the incoming solar radiation and to block infrared energy radiation loss from the earth. The net effect can be either warming or cooling. The essential data are global distributions of the Ice Water Path (IWP) and effective particle size. We have modeled the outgoing earth radiance spectrum between 8 and 1000 mu m as a function of IWP and effective particle size. The results are used to estimate cirrus retrieval accuracies for cirrus from far infrared/submm measurements by Fourier transform spectroscopy. We describe the aircraft-based Far Infrared Sensor for Cirrus (FIRSC) instrument which is currently under construction. We also discuss the potential contribution of far infrared/submm measurements for the validation of cirrus products anticipated in the MTPE MODIS program. C1 NASA, Hampton, VA 23681 USA. RP Nolt, IG (reprint author), NASA, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 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 0-8194-2652-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3220 BP 390 EP 398 PG 9 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BK46E UT WOS:000072275500042 ER PT S AU Smith, GL Barkstrom, BR Lee, RB Wielicki, BA Green, RN Charlock, TP Minnis, P Baum, BA Young, DF Priestley, KJ AF Smith, GL Barkstrom, BR Lee, RB Wielicki, BA Green, RN Charlock, TP Minnis, P Baum, BA Young, DF Priestley, KJ BE Russell, JE TI The CERES/TRMM mission: Early results SO SATELLITE REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Satellite Remote Sensing of Clouds and the Atmosphere III CY SEP 21-23, 1998 CL BARCELONA, SPAIN SP CNR, NASA, European Opt Soc, Commiss European Communities, Directorate Gen Sci Res & Dev, Soc Photo Opt Instrumentat Engineers DE radiometry; climate; Earth Radiation Budget ID RADIOMETERS AB The first Clouds and Earth Radiation Budget Energy System (CERES) instrument has been placed in orbit on the TRMM Spacecraft. This instrument is designed to measure the Earth's radiation budget and also the anisotropy of reflected solar radiation and outgoing longwave radiation. The TRMM orbit and the combination of CERES with other instruments aboard the spacecraft provide a unique opportunity for a number of scientific studies. Results from the on-board calibration systems compare well with ground calibrations. Data products include radiant fluxes at the "top of the atmosphere," surface reflected solar and longwave radiant fluxes (downwelling, upwelling and net) and cloud-radiative interactions. C1 Virginia Polytech Inst & State Univ, Langley Res Ctr, Hampton, VA 23681 USA. RP Smith, GL (reprint author), Virginia Polytech Inst & State Univ, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. RI Baum, Bryan/B-7670-2011 OI Baum, Bryan/0000-0002-7193-2767 NR 32 TC 2 Z9 2 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 0-8194-2954-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3495 BP 246 EP 255 DI 10.1117/12.332703 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BM38V UT WOS:000078582400026 ER PT S AU Thomason, LW Chu, WP Pitts, MC AF Thomason, LW Chu, WP Pitts, MC BE Russell, JE TI The Stratospheric Aerosol and Gas Experiment III SO SATELLITE REMOTE SENSING OF CLOUDS AND THE ATMOSPHERE III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Satellite Remote Sensing of Clouds and the Atmosphere III CY SEP 21-23, 1998 CL BARCELONA, SPAIN SP CNR, NASA, European Opt Soc, Commiss European Communities, Directorate Gen Sci Res & Dev, Soc Photo Opt Instrumentat Engineers AB The Stratospheric Aerosol and Gas Experiment (SAGE III) is the fourth generation of solar occultation instruments designed to measure aerosols and trace gas species in the stratosphere and upper troposphere. It will be launched aboard a Meteor-3M platform in the summer of 1999 and the International Space Station Alpha in 2001. SAGE III preserves the robust characteristics of the SAGE series, including self-calibration and high vertical resolution, and adds new capabilities including a lunar occultation mode. This paper will describe the SAGE III instrument and outline its potential contribution to global change research. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Thomason, LW (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Mail Stop 475, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 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 0-8194-2954-6 J9 P SOC PHOTO-OPT INS PY 1998 VL 3495 BP 286 EP 291 DI 10.1117/12.332682 PG 4 WC Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BM38V UT WOS:000078582400030 ER PT S AU Smith, SM Fleming, JC AF Smith, SM Fleming, JC BE Gu, ZH Maradudin, AA TI BRDF measurements of a new IR black coating with lower reflectance SO SCATTERING AND SURFACE ROUGHNESS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Scattering and Surface Roughness II CY JUL 21-23, 1998 CL SAN DIEGO, CA SP SPIE Int Soc Opt Engn DE reflectance; BRDF; infrared; coatings; black; SiC; restrahlen AB A new coating, whose specular reflectance at far-infrared wavelengths is considerably less than that of either Ames 24E2 or Martin Infrablack and whose diffuse IR reflectance is less than that of Ames 24E2, has been developed through cooperation of NASA-Ames Research Center and Ball Aerospace & Technologies Corporation. The new coating is called Ball IR Black. This new coating is harder and more robust than Ames 24E2 and has a lower tendency to shed particles. It is also rougher and thicker than Ames 24E2. At least two lines of evidence point toward multiple scatter among the huge surface facets of this coating as the principal mechanism behind its lower IR reflectance. A special technique to permit spray application of the coating (which contains SIC grinding compound) has been developed at Ball ATC and may be responsible for the unusually large surface facets. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Ball Aerosp & Technol Corp, Boulder, CO 80302 USA. RP Smith, SM (reprint author), NASA, Ames Res Ctr, MS 244-10, Moffett Field, CA 94035 USA. NR 0 TC 4 Z9 4 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 0-8194-2881-7 J9 P SOC PHOTO-OPT INS PY 1998 VL 3426 BP 333 EP 343 DI 10.1117/12.328473 PG 11 WC Optics SC Optics GA BM07N UT WOS:000077548600035 ER PT B AU Mather, JC Smith, EP Seery, BD Bely, PY Stiavelli, M Stockman, HS Burg, R AF Mather, JC Smith, EP Seery, BD Bely, PY Stiavelli, M Stockman, HS Burg, R BE Smith, EP Koratkar, A TI NGST capabilities and design concepts SO SCIENCE WITH THE NGST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Science with the NGST CY APR 07-09, 1997 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD SP Natl Aeronaut & Space Adm, Space Telescope Sci Inst, European Space Agcy, TRW Inc, Astron Soc Pacific HO GODDARD SPACE FLIGHT CTR AB The Next Generation Space Telescope (NGST) is conceived as a radiatively cooled near IR optimized telescope of more than 4 m aperture, at the Lagrange point L2, launched on an Atlas IIAS class vehicle around 2007. A deployable telescope, adjusted to correct figure after launch, would allow an aperture of 8m. A deployable sunshield and suitable isolation structures would permit radiative cooling to 30-70 K, enabling operation at wavelengths as long as 20 mu m or more at sensitivities limited by the zodiacal light. Planned instruments include wide field cameras and multi-object spectrometers, optimized for the study of distant galaxies and early star formation in the 1-5 mu m band. Such a telescope would be a powerful tool in the study of planet and star formation, circumstellar disks, and the planets, satellites, asteroids: comets, and Kuiper belt objects in our Own Solar system. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mather, JC (reprint author), NASA, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-53-8 J9 ASTR SOC P PY 1998 VL 133 BP 3 EP 23 PG 21 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BK82A UT WOS:000073481000001 ER PT B AU Werner, M AF Werner, M BE Smith, EP Koratkar, A TI SIRTF and WIRE SO SCIENCE WITH THE NGST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Science with the NGST CY APR 07-09, 1997 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD SP Natl Aeronaut & Space Adm, Space Telescope Sci Inst, European Space Agcy, TRW Inc, Astron Soc Pacific HO GODDARD SPACE FLIGHT CTR AB This paper summarizes the status of SIRTF - the Space Infrared Telescope Facility and WIRE - the Wide Field Infrared Explorer, two forthcoming missions which will greatly increase the depth and breadth of our exploration of the Universe at infrared wavelengths and help to define the scientific context for NGST. Both SIRTF and WIRE will be cryogenically-cooled telescopes instrumented with large-format, state of the art monolithic infrared detector arrays. SIRTF will complete NASA's family of Great Observatories and also serve as the first major scientific and technical step in the Origins program. It will be launched in 2001, carrying a complement of imaging and spectroscopic instrumentation. More than 75% of the observing time on SIRTF will be available to the general scientific community. WIRE, to be launched in the Fall of 1998, is a Small Explorer mission which will study the evolution of infrared-emitting starburst galaxies. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Werner, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-53-8 J9 ASTR SOC P PY 1998 VL 133 BP 53 EP 62 PG 10 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BK82A UT WOS:000073481000005 ER PT B AU Dwek, E AF Dwek, E BE Smith, EP Koratkar, A TI The evolution of the elemental abundances in the gas and dust phases of the galaxy SO SCIENCE WITH THE NGST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Meeting Abstract CT Meeting on Science with the NGST CY APR 07-09, 1997 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD SP Natl Aeronaut & Space Adm, Space Telescope Sci Inst, European Space Agcy, TRW Inc, Astron Soc Pacific HO GODDARD SPACE FLIGHT CTR C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-53-8 J9 ASTR SOC P PY 1998 VL 133 BP 249 EP 250 PG 2 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BK82A UT WOS:000073481000027 ER PT B AU Hillman, JJ Glenar, DA Chanover, NJ Blass, WE AF Hillman, JJ Glenar, DA Chanover, NJ Blass, WE BE Smith, EP Koratkar, A TI Acousto-optic cameras for tunable infrared spectral imaging of planetary atmospheres and surfaces SO SCIENCE WITH THE NGST SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Science with the NGST CY APR 07-09, 1997 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD SP Natl Aeronaut & Space Adm, Space Telescope Sci Inst, European Space Agcy, TRW Inc, Astron Soc Pacific HO GODDARD SPACE FLIGHT CTR AB We summarize the acousto-optic tunable filter (AOTF) cam; era development program now being demonstrated at NASA, GSFC with support from the NASA, Code SL, Planetary Instrument Definition and Development Program (PIDDP). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hillman, JJ (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-53-8 J9 ASTR SOC P PY 1998 VL 133 BP 257 EP 262 PG 6 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BK82A UT WOS:000073481000029 ER PT J AU Smith, EJ Marsden, RG AF Smith, EJ Marsden, RG TI The Ulysses mission SO SCIENTIFIC AMERICAN LA English DT Article RP Smith, EJ (reprint author), JET PROPULS LAB,DIV EARTH & SPACE SCI,PASADENA,CA 91109, USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD JAN PY 1998 VL 278 IS 1 BP 74 EP 79 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YL528 UT WOS:A1998YL52800026 ER PT B AU Crenshaw, DM AF Crenshaw, DM BE Brandt, JC Ake, TB Petersen, CC TI GHRS observations of active galaxies SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB The GHRS has had a significant impact on our understanding of active galaxies and, in particular, the environment around the active galactic nuclei. UV spectra obtained at an unprecedented combination of resolution and signal-to-noise are of considerable importance in the ongoing effort to develop detailed physical models of these complex objects. I will review the contributions that the GHRS has made in understanding the various components of active galaxies, with particular emphasis on a relatively new component that is much more ubiquitous than originally thought: intrinsic absorption in the UV spectra of Seyfert 1 galaxies. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Crenshaw, DM (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Comp Sci Corp, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 29 EP 38 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800003 ER PT B AU de Koter, A AF de Koter, A BE Brandt, JC Ake, TB Petersen, CC TI Massive stars observed with the GHRS SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB A review of the contribution of the GHRS to our understanding of very massive stars is presented. The important role of mass loss is discussed in view of the recent discovery of high mass-losing, core-hydrogen-burning Wolf-Rayet-like stars in the 30 Doradus ionizing cluster R136a and of very similar stars in the Galactic cluster NGC 3603. Evolutionary scenarios accounting for a main-sequence Wolf-Rayet or Wolf-Rayet-like phase are compared with these observations. We propose that very massive stars (M-i greater than or similar to 100 M.) may start out their lives as Of/WN-type stars. The predictive power of the theory of line-driven winds is critically investigated. The theoretically expected dependence of mass lass on metallicity is discussed and compared to observations of Galactic, LMC, and SMC stars. We find that (M) over dot proportional to Z(2/3), which is a somewhat stronger dependence than the canonical value of 1/2. The importance of multiple scattering effects in solving the current problems in radiative driving of high-density winds is pointed out. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP de Koter, A (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 39 EP 53 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800004 ER PT B AU Carpenter, KG AF Carpenter, KG BE Brandt, JC Ake, TB Petersen, CC TI Cool stars SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB The enhanced sensitivity, dynamic range, and signal/noise characteristics of the GHRS over previous UV spectrographs have enabled a plethora of exciting, and more quantitative, studies of cool stars. Investigations have included studies of RS CVn systems, determination of Cepheid masses, measurements of the flow and turbulent velocity fields in the outer atmospheres of cool giants and supergiants, transition-region line redshifts and widths, studies of flare stars coordinated with multiple ground and space-based observatories, examinations of the radial structure of the outer atmospheres of red giants in zeta Aur binary systems, and studies of hybrid stars, carbon stars, and very late-type dwarfs. Highlights of these programs are presented along with references to further information. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Carpenter, KG (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Carpenter, Kenneth/D-4740-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 67 EP 81 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800006 ER PT B AU Leckrone, DS Johansson, SG Wahlgren, GM Proffitt, CR Brage, T AF Leckrone, DS Johansson, SG Wahlgren, GM Proffitt, CR Brage, T BE Brandt, JC Ake, TB Petersen, CC TI GHRS spectroscopy of chemically peculiar stars: The chi Lupi Pathfinder Project SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB The HST has provided visual images of the universe of unprecedented clarity and sensitivity. It is less widely known that the HST/GHRS has provided equally breathtaking views of a different kind Of "universe" - a "spectroscopic universe". Nowhere is this better seen than in the extraordinarily complex and beautiful ultraviolet spectrum of the ultra-sharp-lined, non-magnetic, chemically peculiar (CP) star chi Lupi (B9.5pHgMn + A2 Vm). We have begun a systematic exploration and quantitative analysis of this spectrum with the echelle mode of the GHRS. We call this the "The chi Lupi Pathfinder Project", because it is analogous to the exploration and mapping of a previously uncharted land by a diverse team of specialists - in this case astrophysicists and atomic physicists working synergistically. Our objective is to characterize, comprehensively and accurately, the full range of abundance and isotopic anomalies found in the atmosphere of at least one CP star to test and constrain the most widely accepted theoretical scenario for the production of abundance anomalies - radiatively-driven diffusion and gravitational settling. These physical mechanisms are important in several other astrophysical contexts. The surface layers of the CP stars provide a laboratory to investigate the conditions which foster them and the competing mechanisms which retard them. The GHRS echelle data set for chi Lupi covers 345 Angstrom, with S/N approximate to 50-100. We have quadrupled the number of elements for which abundances have been measured in this star, spanning most of the periodic table. These include several elements which have rarely, if ever, been seen before in a star other than the Sun and several examples of isotopically anomalous abundances. We have found systematic trends in these abundance data, which qualitatively support the mechanism of radiatively-driven diffusion and gravitational settling. However, our state-of-the-art theoretical, non-LTE diffusion models have not as yet been successful in sustaining the observed magnitudes of the largest abundance anomalies nor in reproducing anomalous isotope blends. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leckrone, DS (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 135 EP 153 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800011 ER PT B AU Maran, SP AF Maran, SP BE Brandt, JC Ake, TB Petersen, CC TI The Goddard High Resolution Spectrograph on the Hubble Space Telescope after twenty years SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB The principal scientific accomplishments of the Goddard High Resolution Spectrograph, which was part of the scientific complement of the Hubble Space Telescope from April 1990 to February 1997, were amply described during this symposium and are briefly summarized here. They include fundamental discoveries on the nature of the intergalactic hydrogen clouds at low redshift, detailed characterization of the Galactic corona or "halo," new knowledge about the winds, flows, and outer atmospheric layers of a wide variety of stellar types, much information about chemical abundances in a variety of cosmic objects and media, and the detection of oxygen on two Galilean satellites of Jupiter. C1 NASA, Goddard Space Flight Ctr, Space Sci Directorate, Greenbelt, MD 20771 USA. RP Maran, SP (reprint author), NASA, Goddard Space Flight Ctr, Space Sci Directorate, Code 600, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 241 EP 246 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800019 ER PT B AU Wannier, P Andersson, BG Penprase, BE Federman, S Lambert, D AF Wannier, P Andersson, BG Penprase, BE Federman, S Lambert, D BE Brandt, JC Ake, TB Petersen, CC TI The B5 molecular cloud halo: The cool atomic and molecular medium SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB We present GHRS observations of C I and CO toward three stars located behind the edge of the B5 molecular cloud. The column densities of the three fine-structure levels of C I, and of the first three rotational levels of CO can be used together to provide an accurate estimate of the interstellar gas pressure beyond the cloud boundary. That pressure has a strong effect on the continuing evolution of the molecular cloud. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wannier, P (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 ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 285 EP 289 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800027 ER PT B AU Ramaty, R Kozlovsky, B Lingenfelter, RE Reeves, H AF Ramaty, R Kozlovsky, B Lingenfelter, RE Reeves, H BE Brandt, JC Ake, TB Petersen, CC TI Light elements and cosmic rays in the early Galaxy SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB We derive constraints on the cosmic rays responsible for the Be and part of the B observed in stars formed in the early Galaxy: the cosmic rays cannot be accelerated from the ISM; their energy spectrum must be relatively hard (the bulk of the nuclear reactions should occur at > 30 MeV/nucl); and only 10(49) erg/SNII in high metallicity, accelerated-particle kinetic energy could suffice to produce the Be and B. The reverse SNII shock could accelerate the particles. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ramaty, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 303 EP 307 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800033 ER PT B AU Landsman, WB Stecher, TS AF Landsman, WB Stecher, TS BE Brandt, JC Ake, TB Petersen, CC TI The post-mass-transfer binary S1040 in M67 SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Meeting Abstract CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Hughes STX, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 321 EP 321 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800038 ER PT B AU Proffitt, CR Wahlgren, GM Brage, T Brandt, JC Leckrone, DS Johansson, SG AF Proffitt, CR Wahlgren, GM Brage, T Brandt, JC Leckrone, DS Johansson, SG CA GHRS Sci Team BE Brandt, JC Ake, TB Petersen, CC TI Selections from the GHRS atlas of chi Lupi SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB High S/N echelle data of chi Lupi have been obtained at 36 different wavelength settings. The high resolution of the observations combined with the low rotational velocity of chi Lupi (v sin i approximate to 1 km s(-1)), allow the UV spectrum of this star to be seen with unprecedented detail, and provides a unique resource for the study of both atomic physics and stellar atmospheres. C1 NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Proffitt, CR (reprint author), NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 322 EP 325 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800039 ER PT B AU Brage, T Proffitt, CR Wahlgren, GM Leckrone, DS Johansson, S AF Brage, T Proffitt, CR Wahlgren, GM Leckrone, DS Johansson, S BE Brandt, JC Ake, TB Petersen, CC TI Atomic calculations inspired by the GHRS - gf-values, hyperfine structure constants, and isotope shifts for heavy elements SO SCIENTIFIC IMPACT OF THE GODDARD HIGH RESOLUTION SPECTROGRAPH SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Symposium on the Scientific Impact of the Goddard High Resolution Spectrograph CY SEP 11-12, 1996 CL GODDARD SPACE FLIGHT CTR, GREENBELT, MD HO GODDARD SPACE FLIGHT CTR AB GHRS observations of chemically peculiar stars have initiated a new project for calculating atomic properties of heavy elements (Z approximate to 80). The method used is based on large-scale, fully relativistic MCDF, and the data involve accurate gf-values, hyperfine structure parameters, and relative isotope shifts. C1 NASA, Goddard Space Flight Ctr, Comp Sci Corp, Greenbelt, MD 20771 USA. RP Brage, T (reprint author), NASA, Goddard Space Flight Ctr, Comp Sci Corp, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-63-5 J9 ASTR SOC P PY 1998 VL 143 BP 378 EP 381 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74U UT WOS:000076566800053 ER PT S AU Fishman, GJ AF Fishman, GJ CA SIFTER Collaboration BE Bross, AD Ruchti, RC Wayne, MR TI GLAST: Using scintillation fibers for both the tracker and the calorimeter SO SCIFI 97: CONFERENCE ON SCINTILLATING FIBER DETECTORS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT SCIFI 97 Conference on Scintillating Fiber Detectors CY NOV 02-06, 1997 CL NOTRE DAME, IN SP Fermi Natl Accelerator Lab, Univ Notre Dame, US DOE, Natl Sci Fdn, Argonne Natl Lab, Biogeneral Inc, Collimated Holes Inc, Delft Electron Prod BV, Electron Tubes Inc, Hamamatsu Photon BV, Kuraray Corp, LeCroy Corp AB The Gamma-Ray Large Area Space Telescope (GLAST) is planned to be the next major NASA mission in gamma-ray astronomy. It will operate at energies above 20 MeV to study the most energetic objects in the Universe. While the baseline tracker detector for GLAST during the study phase is based on silicon strip detectors, we believe that scintillating fibers have considerable advantages for this purpose. Among the scientific advantages are: larger effective area and better angular resolution at low energies. Practical advantages include: lower cost, the use of a common technology for both the tracker and the calorimeter, lower power consumption, and a simplified thermal design. Several alternative readout methods for the fibers are under study. A set of recent references is provided to indicate the current status of scintillation fiber technology, applications of scintillating fiber systems and readout methods. C1 NASA, Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Fishman, GJ (reprint author), NASA, Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-792-8 J9 AIP CONF PROC PY 1998 VL 450 BP 571 EP 577 PG 7 WC Astronomy & Astrophysics; Instruments & Instrumentation; Physics, Applied; Physics, Multidisciplinary; Physics, Nuclear SC Astronomy & Astrophysics; Instruments & Instrumentation; Physics GA BM12A UT WOS:000077675100061 ER PT S AU Benson, CM Berry, FA Christl, MJ Fountain, WF Gregory, JC Johnson, JS Parnell, TA Takahashi, Y Watts, JW AF Benson, CM Berry, FA Christl, MJ Fountain, WF Gregory, JC Johnson, JS Parnell, TA Takahashi, Y Watts, JW BE Bross, AD Ruchti, RC Wayne, MR TI The SOFCAL experiment SO SCIFI 97: CONFERENCE ON SCINTILLATING FIBER DETECTORS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT SCIFI 97 Conference on Scintillating Fiber Detectors CY NOV 02-06, 1997 CL NOTRE DAME, IN SP Fermi Natl Accelerator Lab, Univ Notre Dame, US DOE, Natl Sci Fdn, Argonne Natl Lab, Biogeneral Inc, Collimated Holes Inc, Delft Electron Prod BV, Electron Tubes Inc, Hamamatsu Photon BV, Kuraray Corp, LeCroy Corp AB SOFCAL is a hybrid instrument with both active and passive chambers to measure the proton and helium cosmic ray spectra from 0.2-10 TeV. An emulsion/x-ray film chamber is situated between a Cerenkov counter and an imaging calorimeter. Scintillating fibers (Sci-Fi) measure the electromagnetic(EM) cascades that develop in the calorimeter and identify the trajectory. The emulsion/x-ray film data provide an in-flight calibration of the Sci-Fi calorimeter. The data reduction techniques will be discussed and interim results of the analysis from a balloon flight will be presented. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Benson, CM (reprint author), NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-792-8 J9 AIP CONF PROC PY 1998 VL 450 BP 598 EP 605 PG 8 WC Astronomy & Astrophysics; Instruments & Instrumentation; Physics, Applied; Physics, Multidisciplinary; Physics, Nuclear SC Astronomy & Astrophysics; Instruments & Instrumentation; Physics GA BM12A UT WOS:000077675100065 ER PT B AU Dimitoglou, G Mendiboure, C Reardon, K Sanchez-Duarte, L AF Dimitoglou, G Mendiboure, C Reardon, K Sanchez-Duarte, L BE Alissandrakis, CE Schmieder, B TI Whole sun catalog: Design and implementation SO SECOND ADVANCES IN SOLAR PHYSICS EUROCONFERENCE: THREE-DIMENSIONAL STRUCTURE OF SOLAR ACTIVE REGIONS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT 2nd Advances in Solar Physics Euroconference - 3-Dimensional Structure of Solar Active Regions CY OCT 07-11, 1997 CL PREVEZA, GREECE SP Astron Soc Pacific, European Union AB The concept of the Whole Sun Catalogue (WSC) is to build an Internet-based, on-line catalog, of basic descriptions and pointers to solar observations archived throughout the world. This facility provides the solar physics community a single point of reference when searching for data. The initial stages for the development of the Whole Sun Catalogue have been completed. This paper provides a description of the environment, proposed architecture, and design of the Catalogue, along with a progress report on the current state of the development life-cycle. C1 NASA, Goddard Space Flight Ctr, SAC, ARD, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, SAC, ARD, Code 682-3, Greenbelt, MD 20771 USA. NR 3 TC 6 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-75-9 J9 ASTR SOC P PY 1998 VL 155 BP 297 EP 301 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM36H UT WOS:000078498100036 ER PT B AU Andretta, V Jordan, SD Muglach, K Garcia, A Jones, HP Penn, MJ Soltau, D AF Andretta, V Jordan, SD Muglach, K Garcia, A Jones, HP Penn, MJ Soltau, D BE Alissandrakis, CE Schmieder, B TI The helium spectrum in the quiet Sun: The January 16/17 and May 7-13 1997 coordinated SOHO/ground-based observational campaigns SO SECOND ADVANCES IN SOLAR PHYSICS EUROCONFERENCE: THREE-DIMENSIONAL STRUCTURE OF SOLAR ACTIVE REGIONS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 2nd Advances in Solar Physics Euroconference - 3-Dimensional Structure of Solar Active Regions CY OCT 07-11, 1997 CL PREVEZA, GREECE SP Astron Soc Pacific, European Union AB We present a description and selected first results of two campaigns of coordinated SOHO and ground-based observations organized in the framework of SOHO joint Observing Program (JOP) #16. The scientific objective of this JOP was the investigation of the formation of the strong He I lambda 584 and He II lambda 304 resonance lines as well as addressing the more general problem of the formation of the helium spectrum in the quiet solar atmosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Andretta, V (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 682-0, Greenbelt, MD 20771 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-75-9 J9 ASTR SOC P PY 1998 VL 155 BP 336 EP 340 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM36H UT WOS:000078498100043 ER PT S AU Davis, L Young, MG Dougherty, D Keo, S Muller, R Maker, P Forouhar, S AF Davis, L Young, MG Dougherty, D Keo, S Muller, R Maker, P Forouhar, S BE Wang, Q Davis, LJ Forouhar, S TI Multi-wavelength arrays of mode-locked lasers for WDM applications SO SEMICONDUCTOR LASERS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Semiconductor Lasers III CY SEP 16-18, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, COS, COEMA DE mode-locked laser; wavelength division multiplexing; laser arrays; solitons AB The continued need for increased bandwidth is driving the pursuit of both increased speed in TDM and more channels in WDM for fiber optic communication systems. Multiwavelength arrays of monolithic mode-locked DBR lasers are an attractive source for future high bit rate (100-800 Gb/s) optical communication systems. Monolithic mode-locked lasers in the colliding-pulse mode-locked configuration have been fabricated, with DBR end mirrors for wavelength selection. A continuous gain region has been employed for ease of fabrication and the elimination of multiple reflections within the cavity. Arrays containing up to 9 wavelengths have been fabricated, with all the wavelengths within the erbium-doped fiber amplifier gain bandwidth. An RF signal is applied to the saturable absorber for synchronization to an external clock and reduction of the phase noise. For a 4.6 mm cavity, short (< 10 ps) optical pulses at high (similar to 18 GHz) repetition rates have been achieved. Low single side-band phase noise values (-107 dBc/Hz @ 100 kHz offset) have been demonstrated, nearly equal to that of the RF source. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect, Pasadena, CA 91109 USA. RP Davis, L (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 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 0-8194-3008-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3547 BP 240 EP 244 DI 10.1117/12.319641 PG 5 WC Optics; Physics, Applied; Physics, Condensed Matter SC Optics; Physics GA BL82M UT WOS:000076839400040 ER PT S AU Yao, XS Maleki, L Wu, C Davis, L Forouhar, S AF Yao, XS Maleki, L Wu, C Davis, L Forouhar, S BE Wang, Q Davis, LJ Forouhar, S TI Semiconductor laser-based optoelectronics oscillators SO SEMICONDUCTOR LASERS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Semiconductor Lasers III CY SEP 16-18, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, COS, COEMA DE opto-electronic oscillator; optical pulse; RF photonics; signal generation; mode-locked lasers; microwave generation; phase noise; jitter AB We demonstrate the realization of coupled opto-electronic oscillators (COEO) with different semiconductor lasers, including a ring laser, a Fabry-Perot laser, and a colliding pulse mode-locked laser. Each COEO can simultaneously generate short optical pulses and spectrally pure RF signals. With these devices, we obtained optical pulses as short as 6 picoseconds and RF signals as high in frequency as 18 GHz with a spectral purity comparable with a HP8561B synthesizer. These experiments demonstrate that COEOs are promising compact sources for generating low jitter optical pulses and low phase noise RF/millimeter wave signals. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yao, XS (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3008-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3547 BP 262 EP 272 DI 10.1117/12.319644 PG 11 WC Optics; Physics, Applied; Physics, Condensed Matter SC Optics; Physics GA BL82M UT WOS:000076839400043 ER PT S AU Wu, C Keo, S Yao, SX Turner, TE Davis, L Young, MG Maleki, L Forouhar, S AF Wu, C Keo, S Yao, SX Turner, TE Davis, L Young, MG Maleki, L Forouhar, S BE Wang, Q Davis, LJ Forouhar, S TI Monolithically integrated InGaAsP/InP Laser/Modulator using identical layer approach for opto-electronic oscillator SO SEMICONDUCTOR LASERS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Semiconductor Lasers III CY SEP 16-18, 1998 CL BEIJING, PEOPLES R CHINA SP SPIE, COS, COEMA DE laser; modulator; mode-locked lasers; microwave generation; opto-electronic oscillator; RF photonics; integrated optics; OEIC AB The microwave optoelectronic oscillator (OEO) has been demonstrated on a breadboard. The future trend is to integrate the whole OEO on a chip, which requires the development of high power and high efficiency integrated photonic components. In this paper, we will present the design and fabrication of an integrated semiconductor laser/modulator using the identical active layer approach on InGaAsP/InP material. The best devices have threshold currents of 50-mA at room temperature for CW operation. The device length is approximately 3-mm, resulting in a mode spacing of lit GHz. For only 5-dBm microwave power applied to the modulator section, modulation response with 30dB resonate enhancement has been observed. This work shows the promise for an on-chip integrated OEO. C1 CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, Pasadena, CA 91109 USA. RP Wu, C (reprint author), CALTECH, Jet Prop Lab, Ctr Space Microelect Technol, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 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 0-8194-3008-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3547 BP 384 EP 393 DI 10.1117/12.319632 PG 10 WC Optics; Physics, Applied; Physics, Condensed Matter SC Optics; Physics GA BL82M UT WOS:000076839400061 ER PT S AU Baumgartner, ET Leger, PC Schenker, PS Huntsberger, TL AF Baumgartner, ET Leger, PC Schenker, PS Huntsberger, TL BE Schenker, PS McKee, GT TI Sensor-fused navigation and manipulation from a planetary rover SO SENSOR FUSION AND DECENTRALIZED CONTROL IN ROBOTIC SYSTEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensor Fusion amd Decentralized Control in Robotic Systems CY NOV 02-03, 1998 CL BOSTON, MA SP SPIE Int Soc Opt Engn DE rover navigation; state estimation; map registration; vision-based manipulation AB This paper describes the development of advanced rover navigation and manipulation techniques for use by NASA's Sample Return Rover. These techniques include an algorithm for estimating the change in the rover's position aid orientation ky registering successive range maps from the rover's hazard avoidance stereo camera pair and the fusion of this information with the rover's wheel odometry. This map registration technique is also extended to register range maps to an a priori model-based range map for relative rover position and orientation determination. Finally, a technique for the robust and precise positioning of a rover-mounted manipulator using visual feedback from the rover's stereo pair is presented. Experimental results for each of these techniques is documented in this paper. C1 CALTECH, Jet Prop Lab, Sci & Technol Dev Sect, Pasadena, CA 91109 USA. RP Baumgartner, ET (reprint author), CALTECH, Jet Prop Lab, Sci & Technol Dev Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 8 Z9 8 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 0-8194-2984-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3523 BP 58 EP 66 DI 10.1117/12.327015 PG 9 WC Automation & Control Systems SC Automation & Control Systems GA BL92J UT WOS:000077158300007 ER PT S AU Neeck, SP Scolese, CJ Bordi, F AF Neeck, SP Scolese, CJ Bordi, F BE Fujisada, H TI EOS AM-1 SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn AB The payload of the EOS AM-1 spacecraft consists of five scientific instruments: the Advanced Spaceborne Thermal Emission Radiometer (ASTER), the Clouds and the Earth Radiant Energy System (CERES), the Multi-Angle Imaging Spectroradiometer (MISR), the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Measurements of Pollution in the Troposphere (MOPITT) instrument. The EOS AM-1 instruments will collect data on the physical and radiative properties of clouds (ASTER, CERES, MISR, MODIS); on air-land and air-sea exchanges of energy, carbon, and water (ASTER, MISR, MODIS); and on vertical profiles of greenhouse gases (MOPITT). The EOS AM-1 spacecraft and its instruments are fully integrated and launch is expected in mid-1999. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Neeck, SP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 2 EP 11 DI 10.1117/12.333619 PG 10 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900001 ER PT S AU Priestley, KJ Barkstrom, BR Bitting, H Lee, RB Pandey, DK Thomas, S Thornhill, KL AF Priestley, KJ Barkstrom, BR Bitting, H Lee, RB Pandey, DK Thomas, S Thornhill, KL BE Fujisada, H TI End-to-end spectral characterization of the Clouds and the Earth's Radiant Energy System (CERES) thermistor bolometer radiometers SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE CERES; TRMM; EOS; radiometry; calibration; Fourier Transform Spectrometry; FTS; spectral; characterization AB Fourier Transform Spectrometer (FTS) techniques are being used to characterize the spectral performance of the Clouds and the Earth's Radiant Energy System (CERES) Flight Models. Each Flight Model contains three scanning thermistor bolometer radiometric channels. These channels measure the broadband filtered radiances in the shortwave (0.3 - 5.0 micron), total (0.3 - >100 micron) and 8 -12 micron water vapor window regions. Accurate characterization of the end-to-end spectral performance is necessary to both determine the filtered radiances from standard sources during radiometric calibration, and to unfilter on-orbit radiance measurements. In order to meet the high calibration requirements deemed necessary by the CERES Science Team, a new technique which measures the broad-band end-to-end spectral response of the CERES sensors with high relative accuracy was necessary. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Priestley, KJ (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. NR 11 TC 5 Z9 5 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 12 EP 22 DI 10.1117/12.333629 PG 11 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900002 ER PT S AU Engman, ET AF Engman, ET BE Fujisada, H TI Development of long wave microwave satellite systems for measuring soil moisture SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE microwave; interferometry; soil moisture; sea surface salinity ID REMOTE-SENSING APPLICATIONS; SURFACE; SENSITIVITY; RAINFALL; FIFE AB The science need for remotely sensed soil moisture has been well established in the hydrologic, climate change and weather forecasting communities. There also have been a number of programs that have demonstrated the feasibility of using long wave microwave sensors for estimating soil moisture. These have ranged from truck mounted sensors, to intensive airborne campaigns with science objectives. Based on this history of truck and aircraft experiments, the science community has settled on a soil moisture product that meets the following criteria: a two day global repeat, a measured layer of 5 cm of soil, a footprint of 20 to 30 km, and an absolute accuracy of +/- 4% volumetric soil moisture. The principal sensor to accomplish this is an L-band passive microwave radiometer. A soil moisture mission is being proposed for the NASA Earth Systems Science Pathfinder (ESSP) mission which has very real constraints of a limited budget which includes the launch vehicle, and a three year award to launch time schedule. Within the past few years there have been a number of mission concepts proposed that meet the challenge of getting st very large antenna in space in order to realize a spatial resolution on the ground that meets the science and applications needs. This paper describes some of the alternative concepts considered to meet these unusual requirements and the ways to solve the very large antenna challenge, and the criteria used to choose the final design for an ESSP proposal. The paper also discusses the alternatives considered to obtain the necessary ancillary data for characterizing the surface roughness, the surface temperature and the attenuation affects of vegetation. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Engman, ET (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Code 974, Greenbelt, MD 20771 USA. NR 16 TC 0 Z9 0 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 65 EP 71 DI 10.1117/12.333668 PG 7 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900007 ER PT S AU Murphy, RE Taylor, RL Neeck, SP Wielicki, BA Barkstrom, BR Crison, M Swenson, JR AF Murphy, RE Taylor, RL Neeck, SP Wielicki, BA Barkstrom, BR Crison, M Swenson, JR BE Fujisada, H TI NPOESS Preparatory Project (NPP) SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn AB The National Aeronautics and Space Administration (NASA) is studying options for future space-based missions, building upon the measurements to be made by the first series of Earth Observing System (EOS) missions. One mission under consideration is the NPOESS Preparatory Project (NPP), a cooperative mission of NASA and the National Polar-orbiting Operational Environmental Satellite System (NPOESS). This mission would utilize new instrument technologies being developed by the NPOESS, with additional NASA requirements, to continue certain measurements from the first series of EOS missions. By flying in the 2005 time period, NPP would provide an early demonstration and validation of new instrument technologies and algorithms in support of future NPOESS missions and extend the critical time series measurements of EOS. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Murphy, RE (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 2 TC 0 Z9 0 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 72 EP 75 DI 10.1117/12.333664 PG 4 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900008 ER PT S AU Eisenman, AR Liebe, CC Zhu, D AF Eisenman, AR Liebe, CC Zhu, D BE Fujisada, H TI Multi-purpose active pixel sensor (APS)-based microtracker SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE active pixel sensor; APS; microcontroller; star tracker; target tracker ID STAR AB A new, photon-sensitive, imaging array, the active pixel sensor (APS) has emerged as a competitor to the CCD imager for use in star and target trackers. The Jet Propulsion Laboratory (JPL) has undertaken a program to develop a new generation, highly integrated, APS-based, multipurpose tracker: the Programmable Intelligent Microtracker (PIM). The supporting hardware used in the PIM has been carefully selected to enhance the inherent advantages of the APS. Adequate computation power is included to perform star identification, star tracking, attitude determination, space docking, feature tracking, descent imaging for landing control, and target tracking capabilities. Its first version uses a JPL developed 256x256-pixel APS and an advanced 32-bit RISC microcontroller. By taking advantage of the unique features of the APS/microcontroller combination, the microtracker will achieve about an order-of-magnitude reduction in mass and power consumption compared to present state-of-the-art star trackers. It will also add the advantage of programmability to enable it to perform a variety of star, other celestial body, and target tracking tasks. The PIM is already proving the usefulness of its design concept for space applications. It is demonstrating the effectiveness of taking such an integrated approach in building a new generation of high performance, general purpose, tracking instruments to be applied to a large variety of future space missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Eisenman, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 1 Z9 2 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 248 EP 254 DI 10.1117/12.333636 PG 7 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900026 ER PT S AU Stirbl, RC Pain, B Cunningham, TJ Hancock, BR McCarty, KP AF Stirbl, RC Pain, B Cunningham, TJ Hancock, BR McCarty, KP BE Fujisada, H TI Next Generation CMOS Active Pixel Sensors for satellite hybrid optical communications/imaging sensor systems SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE APS; active pixel sensor; lasercom; hybrid-optical; MEO; radiation hardened/tolerant; optical communications ID STAR AB Given the current choices of 1) an ever increasing population of large numbers of satellites in low-earth orbit (LEO) constellations for commercial and military global coverage systems, or 2) the alternative of smaller count geosynchronous satellite system constellations in high-earth (HEO), of higher cost and complexity, a number of commercial communications and military operations satellite systems designers are investigating the potential advantages and issues of operating in the mid-earth orbit altitudes (MEO) (between LEO and HEO). At these MEO altitudes both total dose and displacement damage can be traded against the system advantages of fewer satellites required. With growing demand for higher bandwidth communication for real-time earth observing satellite sensor systems, and NASA's interplanetary and deep space virtual unmanned exploration missions in stressing radiation environments, JPL is developing the next generation of smart sensors to address these new requirements of: low-cost, high bandwidth, miniaturization, ultra low-power and mission environment ruggedness. Radiation hardened/tolerant Active Pixel Sensor CMOS imagers that can be adaptively windowed with low power, on-chip control, timing, digital output and provide data-channel efficient on-chip compression, high bandwidth optical communications links are being designed and investigated to reduce size, weight and cost for common optics/hybrid architectures. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stirbl, RC (reprint author), CALTECH, Jet Prop Lab, MS-300-315, Pasadena, CA 91109 USA. NR 9 TC 9 Z9 9 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 255 EP 264 DI 10.1117/12.333665 PG 10 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900027 ER PT S AU Park, HW Habib, S Cunningham, FG Herman, J Bhartia, PK Salikhov, R Chernikov, A AF Park, HW Habib, S Cunningham, FG Herman, J Bhartia, PK Salikhov, R Chernikov, A BE Fujisada, H TI Joint Russian-USA Meteor-3M(2)/TOMS-5 mission SO SENSORS, SYSTEMS, AND NEXT-GENERATION SATELLITES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Sensors, Systems, and Next-Generation Satellites II CY SEP 21-24, 1998 CL BARCELONA, SPAIN SP CNR, NASA, EOS, Commiss European Communities, SPIE - Int Soc Opt Engn DE ozone; ultraviolet; backscatter; spectrometer; TOMS; Meteor-3M ID TOMS AB Meteor-3M(2)/TOMS-5 is a cooperative joint mission between the Russian Space Agency (RSA) and the United States (US) National Aeronautics and Space Administration (NASA). A US Total Ozone Mapping Spectrometer (TOMS) instrument is scheduled to be flown aboard a Russian Meteor-3M satellite in the year 2000. The main science objectives of the mission are to continue global total-ozone measurements to monitor long-term change in global total ozone, to understand processes related to the Antarctic ozone hole, and to improve the understanding of the processes that govern global total ozone. Secondary objectives are to measure aerosol amounts (dust, smoke, volcanic ash, and sulfates) and SO2. This paper describes the Meteor-3M(2) spacecraft, the TOMS-5 experiment operations of Meteor-3M(2)/TOMS-5, and plans for data processing, data archiving and distribution. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Park, HW (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Bhartia, Pawan/A-4209-2016; OI Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632 NR 2 TC 0 Z9 0 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 0-8194-2957-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3498 BP 458 EP 464 DI 10.1117/12.333659 PG 7 WC Engineering, Aerospace; Remote Sensing; Optics SC Engineering; Remote Sensing; Optics GA BM37Y UT WOS:000078533900047 ER PT B AU Blaes, BR Katti, RR Lieneweg, U Natale, M von Wachter, O Wesseling, E AF Blaes, BR Katti, RR Lieneweg, U Natale, M von Wachter, O Wesseling, E GP IEEE IEEE IEEE TI Recent developments in vertical Bloch line data storage SO SEVENTH BIENNIAL IEEE INTERNATIONAL NONVOLATILE MEMORY TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 7th Biennial IEEE Nonvolatile Memory Technology Conference CY JUN 21-24, 1998 CL ALBUQUERQUE, NM SP IEEE Components, Packaging & Mfg Technol Soc, IEEE Comp Soc AB Data storage systems based on vertical Bloch lines have been fabricated in 2 mu m bubble garnet material. The input/output line was fully operational, and experiments in reading and writing showed an encouraging correlation between input and output. Further effort is required to solidify these processes and to establish bit propagation around the storage domains. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Blaes, BR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4518-5 PY 1998 BP 72 EP 76 DI 10.1109/NVMT.1998.723223 PG 5 WC Computer Science, Hardware & Architecture; Engineering, Manufacturing; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BL75K UT WOS:000076575100016 ER PT B AU Bell, LD AF Bell, LD GP IEEE IEEE IEEE TI Spatial and electronic manipulation of silicon nanocrystals by atomic force microscopy SO SEVENTH BIENNIAL IEEE INTERNATIONAL NONVOLATILE MEMORY TECHNOLOGY CONFERENCE, PROCEEDINGS LA English DT Proceedings Paper CT 7th Biennial IEEE Nonvolatile Memory Technology Conference CY JUN 21-24, 1998 CL ALBUQUERQUE, NM SP IEEE Components, Packaging & Mfg Technol Soc, IEEE Comp Soc AB As silicon-based devices shrink, interest is increasing in fast, low-power devices sensitive to small numbers of electrons. Recent work suggests that MOS structures with large arrays of Si nanocrystals comprising a floating gate can be extremely fast, reliable and nonvolatile relative to conventional floating gate memories. In these structures approximately one electron is stored per nanocrystal. Despite promising initial results, current devices have a distribution of charge transit times during writing of nanocrystal ensembles, which limits speed. This behavior is not completely understood, but could be related to a dispersion in oxide thicknesses, nanocrystals interface states, or shifts in the electronic bound states due to size variations. To address these limitations, we have developed an aerosol vapor synthesis/deposition technique for silicon nanocrystals with active size classification, enabling narrow distributions of nanocrystal size (similar to 10-15% of particle in the 2-10 nn size range). The first goal of these experiments has been to use scanning probe techniques to perform particle manipulation and to characterize particle electronic properties and charging on a single-particle basis. Si nanocrystal structures (lines, arrows and other objects) have been formed by contact-mode operation and subsequently imaged in noncontact mode without additional particle motion. Further, single nanocrystal charging by a conducting AFM tip has been observed, detected as an apparent height change due to electrostatic force, followed by a slow relaxation as the stored charge dissipates. Ongoing and future efforts will also be briefly discussed, including narrowing of nanocrystal size distributions, control of oxide thickness on the nanocrystals, and measurements of electron transport through individual particles and ensembles. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Bell, LD (reprint author), CALTECH, Jet Prop Lab, 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 0-7803-4518-5 PY 1998 BP 77 EP 77 DI 10.1109/NVMT.1998.723224 PG 1 WC Computer Science, Hardware & Architecture; Engineering, Manufacturing; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BL75K UT WOS:000076575100017 ER PT J AU Cai, XC Gropp, WD Keyes, DE Melvin, RG Young, DP AF Cai, XC Gropp, WD Keyes, DE Melvin, RG Young, DP TI Parallel Newton-Krylov-Schwarz algorithms for the transonic full potential equation SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE full potential equation; finite elements; domain decomposition; Newton methods; Krylov space methods; overlapping Schwarz preconditioner; parallel computing ID DOMAIN DECOMPOSITION ALGORITHMS; ELLIPTIC PROBLEMS; CONVERGENCE AB We study parallel two-level overlapping Schwarz algorithms for solving nonlinear finite element problems, in particular, for the full potential equation of aerodynamics discretized in two dimensions with bilinear elements. The overall algorithm, Newton-Krylov-Schwarz (NKS), employs an inexact finite difference Newton method and a Krylov space iterative method, with a two-level overlapping Schwarz method as a preconditioner. We demonstrate that NKS, combined with a density upwinding continuation strategy for problems with weak shocks, is robust and economical for this class of mixed elliptic-hyperbolic nonlinear partial differential equations, with proper specification of several parameters. We study upwinding parameters, inner convergence tolerance, coarse grid density, subdomain overlap, and the level of fill-in in the incomplete factorization, and report their effect on numerical convergence rate, overall execution time, and parallel efficiency on a distributed-memory parallel computer. C1 Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Boeing Co, Seattle, WA 98124 USA. RP Cai, XC (reprint author), Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. OI Gropp, William/0000-0003-2905-3029 NR 43 TC 70 Z9 70 U1 1 U2 5 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD JAN PY 1998 VL 19 IS 1 BP 246 EP 265 DI 10.1137/S1064827596304046 PG 20 WC Mathematics, Applied SC Mathematics GA YW904 UT WOS:000071986400018 ER PT S AU Zhou, WL Pirouz, P Powell, JA AF Zhou, WL Pirouz, P Powell, JA BE Pensl, G Morkoc, H Monemar, B Janzen, E TI The origin of triangular surface defects in 4H-SiC CVD epilayers SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE polytypism; epitaxy; surface defects; dislocations; TEM ID GROWTH; FILMS AB 4H-SiC epitaxial thin films grown on bulk substrates using chemical vapor deposition (CVD) frequently exhibit triangular surface defects. Following a comprehensive study of the dislocation content in 4H-epilayers the origin of these defects have been linked to the partial dislocation wails which bound the 3C-SiC platelets in the 4H-SiC matrix. There is strong evidence that at least some of these 3C platelets were formed by a solid state phase transformation mechanism from the 4H matrix. The expansion of these 3C platelets leads to the formation of surface triangles. C1 Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Zhou, WL (reprint author), Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. RI Monemar, Bo/B-3718-2016 NR 16 TC 22 Z9 22 U1 0 U2 3 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 417 EP 420 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000098 ER PT S AU Powell, JA Larkin, DJ Trunek, AJ AF Powell, JA Larkin, DJ Trunek, AJ BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Gaseous etching for characterization of structural defects in silicon carbide single crystals SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE etching; defects; characterization; dislocations; step bunching; transformation ID SIC EPITAXIAL-FILMS; MORPHOLOGY AB Single crystal SiC substrates were subjected to high temperature (1575 degrees C) H-2/C3H8 gaseous etches. The etches resulted in a variety of surface features on 4H-SiC substrates that included elongated hillocks from 10 to > 100 mu m in length by a few mu m in width. In some 4H- and 6H-SiC substrates, the etches resulted in a, continuous coverage of macrosteps. We conclude that the morphology observed after the etching process is influenced by the local Si-C bilayer stacking sequence on the surface of off-(0001) oriented substrates. A model is presented for the formation of the hillocks, based on localized transformations of the 4H substrates during the high temperature etch process. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cortez III, Cleveland, OH 44135 USA. RP Powell, JA (reprint author), NASA, Lewis Res Ctr, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. RI Monemar, Bo/B-3718-2016 NR 13 TC 24 Z9 24 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 421 EP 424 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000099 ER PT S AU Devaty, RP Choyke, WJ Sridhara, SG Clemen, LL Nizhner, DG Larkin, DJ Troffer, T Pensl, G Kimoto, T Kong, HS AF Devaty, RP Choyke, WJ Sridhara, SG Clemen, LL Nizhner, DG Larkin, DJ Troffer, T Pensl, G Kimoto, T Kong, HS BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Optical properties of silicon carbide: Some recent developments SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE absorption; excitons; phosphorus; donors; magneto-optics ID ABSORPTION AB Two topics are discussed: 1) The indirect intrinsic absorption edge of 6H SiC measured using wavelength modulation for both polarizations E perpendicular to (c) over cap and E parallel to (c) over cap. 2) Zeeman spectroscopy of the no-phonon low temperature photoluminescence lines of neutral silicon-site phosphorus four particle complexes in 6H SiC homoepitaxial films grown by chemical vapor deposition. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Univ Erlangen Nurnberg, Inst Angew Phys, D-91058 Erlangen, Germany. Kyoto Univ, Dept Elect Sci & Engn, Kyoto 60601, Japan. Cree Res Inc, Durham, NC 27713 USA. RP Devaty, RP (reprint author), Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RI Monemar, Bo/B-3718-2016 NR 23 TC 6 Z9 6 U1 0 U2 1 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 455 EP 460 PN 1-2 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000107 ER PT S AU Sridhara, SG Nizhner, DG Devaty, RP Choyke, WJ Troffer, T Pensl, G Larkin, DJ Kong, HS AF Sridhara, SG Nizhner, DG Devaty, RP Choyke, WJ Troffer, T Pensl, G Larkin, DJ Kong, HS BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Boron four particle acceptor bound exciton complex in 4H SiC SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE Materials Science Forum LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE boron; bound exciton; four particle complex AB We report the observation of a silicon site shallow boron neutral acceptor four particle bound exciton complex observed by low temperature photoluminescence in 4H SiC homoepitaxial layers doped with boron during CVD growth. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Univ Erlangen Nurnberg, Inst Angew Phys, D-91058 Erlangen, Germany. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. Cree Res Inc, Durham, NC 27713 USA. RP Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RI Monemar, Bo/B-3718-2016 NR 7 TC 4 Z9 4 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI DURNTEN-ZURICH PA KREUZSTRASSE 10, 8635 DURNTEN-ZURICH, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 461 EP 464 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000108 ER PT S AU Sridhara, SG Clemen, LL Nizhner, DG Devaty, RP Choyke, WJ Larkin, DJ AF Sridhara, SG Clemen, LL Nizhner, DG Devaty, RP Choyke, WJ Larkin, DJ BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Phosphorus four particle donor bound exciton complex in 6H SiC SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE phosphorus; bound exciton; valley-orbit splitting; spin-orbit splitting ID CARBIDE AB New lines are observed in the photoluminescence spectra of 6H SiC homoepitaxial films doped with phosphorus during CVD growth. We argue that the lines are associated with the recombination of neutral phosphorus donor four particle bound exciton complexes. C1 Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Sridhara, SG (reprint author), Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. RI Monemar, Bo/B-3718-2016 NR 12 TC 11 Z9 11 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 465 EP 468 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000109 ER PT S AU Fazi, C Neudeck, PG AF Fazi, C Neudeck, PG BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Wide dynamic range RF mixers using wide-bandgap semiconductors SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE wide-dynamic-range; mixers AB This paper describes how wide-bandgap semiconductors, such as silicon carbide or gallium nitride, can be useful in developing a wide dynamic range rf mixer with low intermodulation distortion products, instead of using conventional narrow bandgap semiconductors, such as silicon and gallium arsenide junctions, which have limited dynamic range. A wider dynamic range mixer allows for the reception of weak rf signals, even in the presence of strong undesired signals. This feature also permits closer location of rf sources and receivers with less severe interference. Using an improved high-level mixer can lead to better communications, radar, and navigational equipment for aircraft, maritime, and other applications that share an overcrowded rf spectrum. C1 USA, Res Lab, Adelphi, MD 20783 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Fazi, C (reprint author), USA, Res Lab, 2800 Powder Mill Rd, Adelphi, MD 20783 USA. RI Monemar, Bo/B-3718-2016 NR 1 TC 3 Z9 3 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 913 EP 915 PN 1-2 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000216 ER PT S AU Neudeck, PG Fazi, C AF Neudeck, PG Fazi, C BE Pensl, G Morkoc, H Monemar, B Janzen, E TI Nanosecond risetime pulse characterization of SiC p(+)n junction diode breakdown and switching properties SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE pn junction diode; rectifiers; minority carrier lifetime; reverse recovery; reverse breakdown; surface recombination; bulk recombination; solid-state power devices AB Single-shot nanosecond risetime pulse testing of SiC devices is demonstrated to reveal unique and highly crucial device performance information not obtainable by conventional DC and RP electrical testing, This paper describes some strikingly important device behaviors observed during pulse-testing experiments of 4H-SiC p(+)n junction diodes. Specific observations include: 1) a remarkably fast and catastrophic diode failure mechanism in which an SiC diode fails at a fast-risetime pulse amplitude well. below the DC-measured breakdown voltage, 2) positive temperature coefficient of breakdown voltage behavior in selected 4H-SiC diodes, and 3) average minority carrier lifetimes extracted from reverse recovery switching transients that are dominated by device perimeter surface recombination effects instead of the carrier lifetime inherent to the bulk SiC material itself. All three of these pulse-revealed behaviors provide important insights into fundamental physical issues that impact the performance and reliability of SiC-based electronics, especially high-power SiC devices. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. USA, Res Lab, Adelphi, MD 20783 USA. RP Neudeck, PG (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 77-1, Cleveland, OH 44135 USA. RI Monemar, Bo/B-3718-2016 NR 7 TC 7 Z9 7 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 1037 EP 1040 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000247 ER PT S AU Hunter, GW Neudeck, PG Chen, LY Knight, D Liu, CC Wu, QH AF Hunter, GW Neudeck, PG Chen, LY Knight, D Liu, CC Wu, QH BE Pensl, G Morkoc, H Monemar, B Janzen, E TI SiC-based Schottky diode gas sensors SO SILICON CARBIDE, III-NITRIDES AND RELATED MATERIALS, PTS 1 AND 2 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 7th International Conference on Silicon Carbide, III-Nitrides and Related Materials (ICSCIII-N 97) CY AUG 31-SEP 05, 1997 CL STOCKHOLM, SWEDEN SP Linkoping Univ, ABB Asea Brown Boveri Ltd, Cree Res Ltd, Okmetik OY, Epigress AB, Swedish Res Council Engn Sci, Swedish Nat Sci Res Council, Ericsson Components AB, Thomson CSF, Siemens AG, Daimler Benz AG, City Stockholm, Stockholm Cty Council DE SiC; gas; emission; sensor; high temperature AB Silicon carbide based Schottky diode gas sensors are being developed for high temperature: applications such as emission measurements. Two different types of gas sensitive diodes will be discussed in this paper. By varying the structure of the diode, one can affect the diode stability as well as the diode sensitivity to various gases. It is concluded that the ability of SIC to operate as a high temperature semiconductor significantly enhances the versatility of the Schottky diode gas sensing structure and will potentially allow the fabrication of a SiC-based gas sensor array for versatile high temperature gas sensing applications. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NASA, Cortez Lewis Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Ctr Elect Design, Cleveland, OH 44106 USA. RP Hunter, GW (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RI Monemar, Bo/B-3718-2016 NR 6 TC 6 Z9 7 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-790-0 J9 MATER SCI FORUM PY 1998 VL 264-2 BP 1093 EP 1096 PN 1-2 PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films SC Materials Science GA BK61S UT WOS:000072751000261 ER PT S AU Wang, XY Chang, SC Kao, KH Jorgenson, P Chow, CY AF Wang, XY Chang, SC Kao, KH Jorgenson, P Chow, CY BE Bruneau, CH TI A non-splitting unstructured-triangular-mesh Euler solver based on the method of spacetime conservation element & solution element SO SIXTEENTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN FLUID DYNAMICS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT 16th International Conference on Numerical Methods in Fluid Dynamics CY JUL 06-10, 1998 CL ARCACHON, FRANCE SP NASA AMES Res Ctr, Digital Equipment France, Minist Educ Natl, Enseignement Super & Rech, Minist Defense, CNRS, AEROSPATIALE, Dasault Aviat, Soc Natl Poudres & Explosifs, Council Reg Aquitaine, Minist Affaires Estrangeres, Ctr Natl Etudes Spatiales, CEA, CESTA, MASTER, Ecole Natl Super Chimie & Phys Bordeaux, MAB, Univ Bordeaux 1, Univ Bordeaux 1, CMLA, Ecole Natl Ards & Metiers, Mairie, Bordeaux, Off Tourisme, Conseil Gen Gironde DE space-time CE/SE Euler solver; unstructured triangular mesh; shock wave ID EQUATIONS AB In numerical computations, unstructured grids can be used easily to fit computational domains involving complex geometries. The method of space-time conservation element and solution element (CE/SE method)[1,2] can be used in conjunction with unstructured grids. In this paper, the procedure of developing a non-splitting unstructured-triangular-mesh Euler solver based on the CE/SE method is described. Numerical examples involving complex features of shock waves are presented to show that the CE/SE method works very well even for unstructured triangular grids. C1 NASA, Lewis Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. RP Wang, XY (reprint author), NASA, Lewis Res Ctr, Taitech Inc, Cleveland, OH 44135 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65153-5 J9 LECT NOTES PHYS PY 1998 VL 515 BP 97 EP 102 PG 6 WC Mathematics, Applied; Mechanics; Physics, Fluids & Plasmas SC Mathematics; Mechanics; Physics GA BP77M UT WOS:000086140200016 ER PT S AU Kwak, D Kiris, C Dacles-Mariani, J AF Kwak, D Kiris, C Dacles-Mariani, J BE Bruneau, CH TI An assessment of artificial compressibility and pressure projection methods for incompressible flow simulations SO SIXTEENTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN FLUID DYNAMICS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT 16th International Conference on Numerical Methods in Fluid Dynamics CY JUL 06-10, 1998 CL ARCACHON, FRANCE SP NASA AMES Res Ctr, Digital Equipment France, Minist Educ Natl, Enseignement Super & Rech, Minist Defense, CNRS, AEROSPATIALE, Dasault Aviat, Soc Natl Poudres & Explosifs, Council Reg Aquitaine, Minist Affaires Estrangeres, Ctr Natl Etudes Spatiales, CEA, CESTA, MASTER, Ecole Natl Super Chimie & Phys Bordeaux, MAB, Univ Bordeaux 1, Univ Bordeaux 1, CMLA, Ecole Natl Ards & Metiers, Mairie, Bordeaux, Off Tourisme, Conseil Gen Gironde DE incompressible flow; artificial compressibility; projection method ID NAVIER-STOKES EQUATIONS AB Performance of the two commonly used numerical procedures, one based on artificial compressibility method and the other pressure projection method, are compared. These formulations are selected primarily because they are designed for three-dimensional applications. The computational procedures are compared by obtaining steady state solutions of a wake vortex and unsteady solutions of a curved duct flow. For steady computations, artificial compressibility was very efficient in terms of computing time and robustness. For an unsteady flow which requires small physical time step, pressure projection method was found to be computationally more efficient than an artificial compressibility method. This comparison is intended to give some basis for selecting a method or a flow solution code for large three-dimensional applications where computing resources become a critical issue. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kwak, D (reprint author), NASA, Ames Res Ctr, MS T27B-1, Moffett Field, CA 94035 USA. NR 7 TC 1 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65153-5 J9 LECT NOTES PHYS PY 1998 VL 515 BP 177 EP 182 PG 6 WC Mathematics, Applied; Mechanics; Physics, Fluids & Plasmas SC Mathematics; Mechanics; Physics GA BP77M UT WOS:000086140200028 ER PT S AU Liou, MS AF Liou, MS BE Bruneau, CH TI Recent progress and applications of AUSM(+) SO SIXTEENTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN FLUID DYNAMICS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT 16th International Conference on Numerical Methods in Fluid Dynamics CY JUL 06-10, 1998 CL ARCACHON, FRANCE SP NASA AMES Res Ctr, Digital Equipment France, Minist Educ Natl, Enseignement Super & Rech, Minist Defense, CNRS, AEROSPATIALE, Dasault Aviat, Soc Natl Poudres & Explosifs, Council Reg Aquitaine, Minist Affaires Estrangeres, Ctr Natl Etudes Spatiales, CEA, CESTA, MASTER, Ecole Natl Super Chimie & Phys Bordeaux, MAB, Univ Bordeaux 1, Univ Bordeaux 1, CMLA, Ecole Natl Ards & Metiers, Mairie, Bordeaux, Off Tourisme, Conseil Gen Gironde DE numerical flux; low Mach preconditioning; Navier-Stokes applications; overset and unstructured grids ID FLUX SPLITTING SCHEME AB Since the inception of the numerical flux scheme, AUSM [Liou and Steffen (93)], several versions [Liou (96), Wada and Lion (97), Edwards and Lion (97)] have been proposed, mainly for improving accuracy and robustness. The AUSM-family has been applied by researchers for various flow applications and fields beside the conventional aerospace and mechanical engineering. In this paper, we will focus on the version, AUSM(+) [Liou (96)], and report progress that has been recently achieved. We will concern ourselves with flows in practical devices - typically, turbulent flows in complex geometry, manifested with complex physics. Specifically, we will show calculations using (1) unstructured grid, (2) Chimera (overset) grid, and (3) a new preconditioned AUSM(+) [Edwards and Lieu (97)]. The calculated results show excellent agreement with measured data. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Liou, MS (reprint author), NASA, Lewis Res Ctr, MS 5-11, Cleveland, OH 44135 USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65153-5 J9 LECT NOTES PHYS PY 1998 VL 515 BP 302 EP 307 PG 6 WC Mathematics, Applied; Mechanics; Physics, Fluids & Plasmas SC Mathematics; Mechanics; Physics GA BP77M UT WOS:000086140200047 ER PT S AU Arian, E Salas, MD AF Arian, E Salas, MD BE Bruneau, CH TI Adjoint formulation using auxiliary boundary equations (ABEs) demonstrated on the Stokes equations SO SIXTEENTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN FLUID DYNAMICS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT 16th International Conference on Numerical Methods in Fluid Dynamics CY JUL 06-10, 1998 CL ARCACHON, FRANCE SP NASA AMES Res Ctr, Digital Equipment France, Minist Educ Natl, Enseignement Super & Rech, Minist Defense, CNRS, AEROSPATIALE, Dasault Aviat, Soc Natl Poudres & Explosifs, Council Reg Aquitaine, Minist Affaires Estrangeres, Ctr Natl Etudes Spatiales, CEA, CESTA, MASTER, Ecole Natl Super Chimie & Phys Bordeaux, MAB, Univ Bordeaux 1, Univ Bordeaux 1, CMLA, Ecole Natl Ards & Metiers, Mairie, Bordeaux, Off Tourisme, Conseil Gen Gironde DE adjoint; aerodynamic optimization; Stokes; optimal shape AB A general method is presented for formulating proper boundary value problems from cost functionals considered "inadmissible" in the literature. In [Arian 97], a generic derivation is provided for PDEs modeling fluid-dynamics: potential, Euler, and Navier-Stokes. We claim that for such problems additional terms should be included in the Lagrangian functional when deriving the adjoint equations. These terms are obtained from the restriction of the interior PDE to the control surface and will be called auxiliary boundary equations (ABEs). Tn this report we give a demonstration of the use of ABEs to derive the continuous adjoint equations in the case of an incomplete cost functional for a case study governed by the Stokes equations. We show that the resulting equations are consistent with the discrete adjoint equations. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Arian, E (reprint author), NASA, Langley Res Ctr, ICASE, M-S 403, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65153-5 J9 LECT NOTES PHYS PY 1998 VL 515 BP 355 EP 360 PG 6 WC Mathematics, Applied; Mechanics; Physics, Fluids & Plasmas SC Mathematics; Mechanics; Physics GA BP77M UT WOS:000086140200055 ER PT S AU Pulliam, TH MacCormack, RW Venkateswaran, S AF Pulliam, TH MacCormack, RW Venkateswaran, S BE Bruneau, CH TI Convergence characteristics of approximate factorization methods SO SIXTEENTH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN FLUID DYNAMICS SE LECTURE NOTES IN PHYSICS LA English DT Proceedings Paper CT 16th International Conference on Numerical Methods in Fluid Dynamics CY JUL 06-10, 1998 CL ARCACHON, FRANCE SP NASA AMES Res Ctr, Digital Equipment France, Minist Educ Natl, Enseignement Super & Rech, Minist Defense, CNRS, AEROSPATIALE, Dasault Aviat, Soc Natl Poudres & Explosifs, Council Reg Aquitaine, Minist Affaires Estrangeres, Ctr Natl Etudes Spatiales, CEA, CESTA, MASTER, Ecole Natl Super Chimie & Phys Bordeaux, MAB, Univ Bordeaux 1, Univ Bordeaux 1, CMLA, Ecole Natl Ards & Metiers, Mairie, Bordeaux, Off Tourisme, Conseil Gen Gironde DE approximate factorization; numerical analysis AB Convergence characteristics and efficiency of several implicit approximate factorization schemes (including standard ADI, a diagonally dominant form of ADI:DDADI and a diagonalized version of DDADI:D3ADI) are examined using stability analysis and numerical convergence studies. We also discuss the use of subiterations to eliminate the approximate factorization errors and thereby improve convergence behavior. Numerical convergence studies are utilized to demonstrate the theoretical findings. We conclude that, ADI and D3ADI with sub-iterations perform equally well in terms of efficiency, although D3ADI may be more robust with respect to time step selection. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Pulliam, TH (reprint author), NASA, Ames Res Ctr, MS T27B-1, Moffett Field, CA 94035 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0075-8450 BN 3-540-65153-5 J9 LECT NOTES PHYS PY 1998 VL 515 BP 409 EP 414 PG 6 WC Mathematics, Applied; Mechanics; Physics, Fluids & Plasmas SC Mathematics; Mechanics; Physics GA BP77M UT WOS:000086140200064 ER PT B AU Waheed, A Yan, J AF Waheed, A Yan, J BE Boukerche, A Das, SK Williamson, C Wilsey, P TI Performance modeling and measurement of parallelized code for distributed shared memory multiprocessors SO SIXTH INTERNATIONAL SYMPOSIUM ON MODELING, ANALYSIS AND SIMULATION OF COMPUTER AND TELECOMMUNICATION SYSTEMS, PROCEEDINGS LA English DT Proceedings Paper CT 6th International Symposium on Modeling, Analysis and Simulation of Computer and Telecommunication Systems (MASCOTS 98) CY JUL 19-24, 1998 CL MONTREAL, CANADA SP IEEE, Comp Soc, Tech Comm Comp Architecture, IEEE Comp Soc, Tech Comm Comp Architecture, IFIPS, IBM, Canada, CAE, Canada, CRIM, Montreal, IEEE, Montreal Sect, Univ N Texas Denton AB This paper presents a model to evaluate the performance and overhead of par parallelizing sequential code using compiler directives for multiprocessing on distributed shared memory (DSM) systems. We parallelized the sequential implementation of NAS benchmarks using native Fortran77 compiler directives on an Origin2000, which is a DSM system. We report measurement based performance of these parallelized benchmarks from four perspectives: efficacy of parallelization process, scalability; parallelization overhead; and comparison with hand-parallelized and -optimized version of the same benchmarks. Our results indicate that sequential programs can conveniently be parallelized for DSM systems using compiler directives but realizing performance gains as predicted by the performance model depends primarily on minimizing architecture-specific data locality overhead. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP Waheed, A (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, Mail Stop T27A-2, Moffett Field, CA 94035 USA. NR 0 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 0-8186-8566-2 PY 1998 BP 161 EP 166 DI 10.1109/MASCOT.1998.693690 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BL38T UT WOS:000075345800023 ER PT S AU Adamovsky, G Baumbick, RJ Tabib-Azar, M AF Adamovsky, G Baumbick, RJ Tabib-Azar, M BE Claus, RO Spillman, WB TI Photonic elements in smart systems for use in aerospace platforms SO SMART STRUCTURES AND MATERIALS 1998: SENSORY PHENOMENA AND MEASUREMENT INSTRUMENTATION FOR SMART STRUCTURES AND MATERIALS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Sensory Phenomena and Measurement Instrumentation for Smart Structures and Materials CY MAR 02-04, 1998 CL SAN DIEGO, CA SP SPIE, Soc Exptl Mech Inc, Amer Soc Mech Engineers, BFGoodrich Aerosp DE smart structures; smart systems; sensing; photonics; aircraft systems AB To compete globally in the next millennium, designers of new transportation vehicles will have to be innovative. Keen competition will reward innovative concepts that are developed and proven first. In order to improve reliability of aerospace platforms and reduce operating costs, new technologies must be exploited to produce autonomous systems, based On highly distributed, smart systems, which can be treated as line replaceable units (LRU's). These technologies include photonics, which provide sensing and information transfer functions, and micro electro mechanical systems (MEMS) that Pill produce the actuation and, in some cases, may even provide a computing capability that resembles the hydromechanical control systems used in older aircraft systems. The combination of these technologies will provide unique systems that will enable achieving the reliability and cost goals dictated by global market. In the article we review some of these issues and discuss a role of photonics in smart systems for aerospace platforms. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Adamovsky, G (reprint author), NASA, Lewis Res Ctr, MS 77-1, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 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 0-8194-2774-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3330 BP 200 EP 208 DI 10.1117/12.317001 PG 9 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Optics SC Engineering; Instruments & Instrumentation; Optics GA BL49Q UT WOS:000075701500023 ER PT S AU Thakoor, S Poosanaas, P Morookian, JM Yavrouian, A Lowry, L Marzwell, N Nelson, JG Neurgaonkar, RR Uchino, K AF Thakoor, S Poosanaas, P Morookian, JM Yavrouian, A Lowry, L Marzwell, N Nelson, JG Neurgaonkar, RR Uchino, K BE Varadan, VK McWhorter, PJ Singer, RA Vellekoop, MJ TI Optical microactuation in piezoceramics SO SMART STRUCTURES AND MATERIALS 1998: SMART ELECTRONICS AND MEMS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Smart Electronics and MEMS CY MAR 02-04, 1998 CL SAN DIEGO, CA SP SPIE, Soc Exptl Mech Inc, Amer Soc Mech Engineers, BFGoodrich Aerosp AB Optically/electrically operable flexible film microactuators that can offer upto two orders higher efficiency of photonic to mechanical conversion compared to ceramic actuators are conceptualized. A polarized ceramic wafer of non-centrosymmetric perovskite ferroelectric ABO(3) compounds, such as lead lanthanum zirconate titanate (PLZT), when exposed to an illumination (similar to 350 to 400 nm wavelength) close to the bandgap energy, can generate a large photovoltage (similar to 1.0 kV/mm) across its length, and by the inverse piezoelectric effect cause the piezoceramic wafer to deflect in the direction away from the illumination. The optical actuation effect in piezoceramic wafers is investigated as a function of thickness, composition, and surface roughness. Such flexible microactuators would enable a new generation of micro-electro-mechanical and micro-opto-mechanical systems where the actuation will not be restricted by the clamping effect due to the rigid substrate as in the current silicon based micromachined structures. To deposit the piezoceramic film directly onto a flexible substrate, the substrate must have high temperature stability, high strength (Young's Modulus similar to 4.9x10(10) N/m(2)), a close match of thermal coefficients of expansion with the piezoceramic film, and a tailorable crystal orientation in order to provide a desired template for growth of oriented PLZT. This paper also presents a comparison of a variety of flexible substrate films and fibers and our recent results on polybenzoxazole (PBO), a polymeric candidate for a flexible high temperature substrate. Variation of the properties of PBO as a function of temperature are also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Thakoor, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 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 0-8194-2772-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3328 BP 376 EP 391 PG 16 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BL49P UT WOS:000075701400040 ER PT S AU Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, JO Smith, J AF Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, JO Smith, J BE Wuttig, M TI Low-mass muscle actuators using electroactive polymers (EAP) SO SMART STRUCTURES AND MATERIALS 1998: SMART MATERIALS TECHNOLOGIES SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Smart Materials Technologies CY MAR 04-05, 1998 CL SAN DIEGO, CA SP SPIE, Soc Exptl Mech Inc, Amer Soc Mech Engineers, BFGoodrich Aerosp DE miniature robotics; electroactive polymers; hand simulation; electroactive actuators; EAP materials AB NASA is seeking to reduce the mass, size, consumed power, and cost of the instrumentation used in its future missions. An important element of many instruments and devices is the actuation mechanism and electroactive polymers offer an effective alternative to current actuators. In this study, two families of electroactive polymer (EAP) materials were investigated, including bending ionomers and longitudinal electrostatically driven elastomers. These materials were demonstrated to effectively actuate manipulation devices and their performance is being enhanced in this on-going study. The recent observations are reported in this paper, which also include cryovac tests at conditions that simulate Mars environment. Tests at T=-140 degrees C and P-l Torr,which are below Mars conditions, showed that the bending actuator was still responding with a measurable actuation displacement. Analysis of the electrical characteristics of the ionomer showed that it is a current driven material rather than voltage driven. Measurements of transient currents in response to a voltage step shows a time constant on the order of few seconds with a response speed that is enhanced with the decrease in drive voltage. The ionomer main limitation is its requirement for being continuously moist. Tests showed that while the performance degrades as the material becomes dry, its AC impedance increases, reaching an order of magnitude higher than the wet ionomer. This response provides a gauging indication of the material wetness status. Methods of forming the equivalent of a skin to protect the moisture content of the ionomer are being sought and a limited success was observed using thick platinum electroding as well as when using polymeric coating. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 23 Z9 23 U1 1 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2768-3 J9 P SOC PHOTO-OPT INS PY 1998 VL 3324 BP 218 EP 223 DI 10.1117/12.316866 PG 6 WC Engineering, Biomedical; Materials Science, Multidisciplinary; Optics SC Engineering; Materials Science; Optics GA BL49N UT WOS:000075701300024 ER PT S AU Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, JO Smith, J AF Bar-Cohen, Y Xue, T Shahinpoor, M Simpson, JO Smith, J BE Regelbrugge, ME TI Flexible, low-mass robotic arm actuated by electroactive polymers SO SMART STRUCTURES AND MATERIALS 1998: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Smart Structures and Integrated Systems CY MAR 02-05, 1998 CL SAN DIEGO, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp DE miniature robotics; electroactive polymers; hand simulation; EAP actuators; surface wiper; EAP gripper AB Miniature, lightweight, low-cost actuators that consume low-power can be used to develop unmatched robotic devices to make an impact on many technology areas. Electroactive polymers (EAP) actuators offer the potential to produce such devices and they induce relatively large bending and longitudinal actuation strains. This reported study is concentrating on the development of effective EAPs and the resultant enabling mechanisms employing their unique characteristics. Several EAP driven mechanisms, which emulate human hand, were developed including a gripper, manipulator arm and surface wiper. The manipulator arm was made of a composite rod with a lifting actuator consisting of a scrolled rope that is activated longitudinally by an electrostatic field. A gripper was made to serve as an end effector and it consisted of multiple bending EAP fingers for grabbing and holding such objects as rocks. An EAP surface wiper was developed to operate like a human finger and to demonstrate the potential to remove dust from optical and IR windows as well as solar cells. These EAP driven devices are taking advantage of the large actuation displacement of these materials for applications that have limited requirement for actuation force capability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 6 Z9 6 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 0-8194-2773-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3329 BP 52 EP 57 DI 10.1117/12.316938 PN 1-2 PG 6 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BL52W UT WOS:000075786600006 ER PT S AU Bar-Cohen, Y Bao, XQ Grandia, W AF Bar-Cohen, Y Bao, XQ Grandia, W BE Regelbrugge, ME TI Rotary ultrasonic motors actuated by traveling flexural waves SO SMART STRUCTURES AND MATERIALS 1998: SMART STRUCTURES AND INTEGRATED SYSTEMS, PTS 1 AND 2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT SPIE Conference on Smart Structures and Integrated Systems CY MAR 02-05, 1998 CL SAN DIEGO, CA SP SPIE, Soc Exptl Mech, Amer Soc Mech Engineers, BFGoodrich Aerosp DE piezoelectric motors; ultrasonic motors (USMs); stators and rotors; modal analysis; actuators; active materials AB Efficient miniature actuators that are compact and consume low power are needed to drive telerobotic devices and space mechanisms in future NASA missions. Ultrasonic rotary motors have the potential to meet this NASA need and they are developed as actuators for miniature telerobotic applications. The technology that has emerged in commercial products requires rigorous analytical tools for effective design of such motors. A finite element analytical model was developed to examine the excitation of flexural plate wave traveling in a rotary piezoelectrically actuated motor. The model uses annular finite elements that are applied to predict the excitation frequency and modal response of an annular stator. This model is being developed to enable the design of efficient ultrasonic motors (USMs) and it incorporates the details of the stator which include the teeth, piezoelectric crystals, stator geometry, etc. The theoretical predictions were corroborated experimentally for the stator. Parallel to this effort, USMs are made and incorporated into a robotic arm and their capability to operate at the environment of Mars is being studied. Motors with two different actuators layout were tested at cryovac conditions and were shown to operate down to -150 degrees C and 16-mTorr when the activation starts at ambient conditions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2773-X J9 P SOC PHOTO-OPT INS PY 1998 VL 3329 BP 794 EP 800 DI 10.1117/12.316950 PN 1-2 PG 7 WC Acoustics; Engineering, Aerospace; Engineering, Mechanical; Optics SC Acoustics; Engineering; Optics GA BL52W UT WOS:000075786600070 ER PT S AU Duvall, TL AF Duvall, TL GP EUROPEAN SPACE AGCY EUROPEAN SPACE AGCY TI Recent results and theoretical advances in local helioseismology SO SOHO 6/GONG 98 WORKSHOP ON STRUCTURE AND DYNAMICS OF THE INTERIOR OF THE SUN AND SUN-LIKE STARS, VOLS 1 AND 2: VOL 1: SESSIONS I-III, VOL 2: SESSIONS IV-VI SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO 6/GONG 98 Workshop on Structure and Dynamics of the Interior of the Sun and Sun-Like Stars CY JUN 01-04, 1998 CL BOSTON, MA SP European Space Agcy, NASA, Natl Sci Fdn, Smithsonian Astrophys Observ DE local helioseismology; sun ID TIME-DISTANCE HELIOSEISMOLOGY; 5-MINUTE OSCILLATIONS; P-MODES; SUNSPOTS; SCATTERING; ABSORPTION; ANTIPODES; SURFACE; PROBE; SUN AB Local helioseismology is being used to study a variety of solar phenomena, including active regions, supergranulation, meridional circulation, torsional oscillations, solar rotation, and giant cell convection. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Duvall, TL (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RI Duvall, Thomas/C-9998-2012 NR 44 TC 25 Z9 25 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-672-4 J9 ESA SP PUBL PY 1998 VL 418 BP 581 EP 585 PN 1&2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM37B UT WOS:000078509100110 ER PT S AU Turmon, M Pap, JM Mukhtar, S AF Turmon, M Pap, JM Mukhtar, S GP EUROPEAN SPACE AGCY EUROPEAN SPACE AGCY TI Automatically finding solar active regions using SOHO/MDI photograms and magnetograms SO SOHO 6/GONG 98 WORKSHOP ON STRUCTURE AND DYNAMICS OF THE INTERIOR OF THE SUN AND SUN-LIKE STARS, VOLS 1 AND 2: VOL 1: SESSIONS I-III, VOL 2: SESSIONS IV-VI SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT SOHO 6/GONG 98 Workshop on Structure and Dynamics of the Interior of the Sun and Sun-Like Stars CY JUN 01-04, 1998 CL BOSTON, MA SP European Space Agcy, NASA, Natl Sci Fdn, Smithsonian Astrophys Observ DE solar irradiance; magnetograms; photograms; image processing; labeling; segmentation ID IRRADIANCE; LUMINOSITY; CYCLE; SUN AB This paper presents a new application of statistically-based methods for automatically identifying the various surface structures on the Sun which may contribute to observed changes in solar total and spectral irradiance. These structures are divided for our purposes into three types: quiet sun, faculae, and active regions. The procedures described here find labelings from synchronized full-disk high-resolution magnetic-field and light-intensity maps from the Michelson Doppler Imager experiment on SoHO. Statistical models characterizing the properties of the region types are found from expert identification of a sample set of regions. Once these parameters are fixed, the inference procedure becomes to maximize the probability of an image-labeling given the observed data. This allows objective and automated classification of a large set of images. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Turmon, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 6 Z9 6 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-672-4 J9 ESA SP PUBL PY 1998 VL 418 BP 979 EP 984 PN 1&2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BM37B UT WOS:000078509100183 ER PT B AU Levine, ER Kimes, DS AF Levine, ER Kimes, DS BE Lal, R Kimble, JM Follett, RF Stewart, BA TI Predicting soil carbon in mollisols using neural networks SO SOIL PROCESSES AND THE CARBON CYCLE SE ADVANCES IN SOIL SCIENCE-BOCA RATON LA English DT Proceedings Paper CT Symposium on Carbon Sequestration in Soils CY JUL, 1996 CL OHIO STATE UNIV, COLUMBUS, OH SP USDA, Nat Resources Conservat Serv, Agr Res Serv, Forest Serv, Soil Sci Soc Amer, Ohio State Univ HO OHIO STATE UNIV C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Levine, ER (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 4 U1 0 U2 0 PU CRC PRESS-TAYLOR & FRANCIS GROUP PI BOCA RATON PA 6000 BROKEN SOUND PARKWAY NW, STE 300, BOCA RATON, FL 33487-2742 USA BN 0-8493-7441-3 J9 ADV SOIL S PY 1998 BP 473 EP 484 PG 12 WC Soil Science SC Agriculture GA BK14T UT WOS:000071337600032 ER PT J AU Mecherikunnel, AT AF Mecherikunnel, AT TI Solar total irradiance: A reference value for solar minimum SO SOLAR PHYSICS LA English DT Article ID PHOTOMETRIC SUNSPOT INDEX; LUMINOSITY; VARIABILITY; LINE; MODULATION; SPACECRAFT; NIMBUS-7; CONSTANT; SUN; UV AB Simultaneous solar total irradiance observations performed by absolute radiometers on board satellites during the quiet-Sun period between solar cycles 21 and 22 (1985-1987), are analyzed to determine the solar total irradiance at 1 AU for the solar minimum. During the quiet-Sun period the total solar irradiance, UV irradiance, and the various solar activity indices show very little fluctuation. However, the absolute value of the solar total irradiance derived from the observations differ within the accuracy of the radiometers used in the measurements. Therefore, the question often arises about a reference value of the solar total irradiance for use in climate models and for computation of geophysical, and atmospheric parameters. This research is conducted as a part of the Solar Electromagnetic Radiation Study for Solar Cycle 22 (SOLERS22). On the basis of the study we recommended a reference value of 1367.0 +/- 0.04 W m(-2) for the solar total irradiance at 1 AU for a truly quiet Sun. We also find that the total solar irradiance data for the quiet-Sun period reveals strong short-term irradiance variations. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Mecherikunnel, AT (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 38 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1998 VL 177 IS 1-2 BP 11 EP 23 DI 10.1023/A:1004972315783 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE672 UT WOS:000072818400002 ER PT J AU Tobiska, WK Eparvier, FG AF Tobiska, WK Eparvier, FG TI EUV97: Improvements to EUV irradiance modeling in the soft X-rays and FUV SO SOLAR PHYSICS LA English DT Article ID INTERPLANETARY LYMAN-ALPHA; SAN-MARCO ASSI; SOLAR EUV; FLUX MODEL; ULTRAVIOLET SPECTROMETER; COMPARISON EXPERIMENT-1; RADIATION; GALILEO; MAXIMUM; ABOARD AB EUV97 is a salar EUV empirical model that incorporates revised soft X-ray fluxes from the SOLRAD-11 satellite (1976-1979) and uses L alpha recently recalibrated to the UARS satellite (1991-present) SOLSTICE L alpha. The soft X-ray data have been revised from the original flux values using Mewe's spectral fits to the data. The recalibrated AE-E and SME L alpha datasets use UARS L alpha for absolute flux values to provide two solar cycles of L alpha irradiance extending back to 1977. L alpha is used by EUV97 as a proxy for chromospheric EUV irradiances. The EUV97 empirical solar model takes its heritage from the EUV91 model based on a multiple linear regression technique that fits soft X-ray and EUV irradiances to 10.7 cm flux for transition region and coronal emissions or to L alpha and He I 10830 Angstrom EW for chromospheric emissions. C1 Telos JPL, Pasadena, CA 91109 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Tobiska, WK (reprint author), Telos JPL, MS 264-723,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 53 TC 98 Z9 98 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1998 VL 177 IS 1-2 BP 147 EP 159 DI 10.1023/A:1004931416167 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE672 UT WOS:000072818400011 ER PT J AU Mahajan, KK Upadhyay, HO Sethi, NK Hoegy, WR Pesnell, WD Brace, LH AF Mahajan, KK Upadhyay, HO Sethi, NK Hoegy, WR Pesnell, WD Brace, LH TI Pioneer Venus Orbiter measurements of solar EUV flux during solar cycles 21 and 22 SO SOLAR PHYSICS LA English DT Article ID LANGMUIR PROBE; PLANETARY IONOSPHERES; IRRADIANCE; SPECTROMETER; MODEL AB The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which measured temperature and concentration of electrons in the ionosphere of Venus. When the probe was outside the Venus ionosphere and was in the solar wind, the probe current was entirely due to solar photons striking the probe surface. This probe thus measured integrated solar EUV flux (Ipe) over a 13-year period from January 1979 to December 1991, thereby covering the declining phase of solar cycle 21 and the rising phase of solar cycle 22. In this paper, we examine the behavior of Ipe translated to the solar longitude of Earth (to be called EIpe) during the two solar cycles. We find that total EUV flux changed by about 60% during solar cycle 21 and by about 100% in solar cycle 22. We also compare this flux with other solar activity indicators such as F-10.7, L alpha, and the solar magnetic field. We find that while the daily values of EIpe are highly correlated with F-10.7 (correlation coefficient 0.87), there is a large scatter in EIpe for any value of this Earth-based index. A comparison of EIpe with SME and UARS SOLSTICE L alpha measurements taken during the same period shows that EIpe tracks L alpha quite faithfully with a correlation coefficient of 0.94. Similar comparison with the solar magnetic field (Bs) shows that EIpe correlates better with Bs than with F-10.7. We also compare EIpe with total solar irradiance measured during the same period. C1 Natl Phys Lab, Radio & Atmospher Sci Div, New Delhi 110012, India. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nomad Res Inc, Bowie, MD 20716 USA. Univ Michigan, Space Phys Lab, Ann Arbor, MI 48109 USA. RP Mahajan, KK (reprint author), Natl Phys Lab, Radio & Atmospher Sci Div, New Delhi 110012, India. RI Pesnell, William/D-1062-2012 OI Pesnell, William/0000-0002-8306-2500 NR 33 TC 6 Z9 6 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JAN PY 1998 VL 177 IS 1-2 BP 203 EP 216 DI 10.1023/A:1004991431713 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZE672 UT WOS:000072818400017 ER PT B AU Lissauer, JJ AF Lissauer, JJ BE Lazzaro, D Martins, RV FerrazMello, S Fernandez, J Beauge, C TI Formation of planetary systems SO SOLAR SYSTEM FORMATION AND EVOLUTION SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Meeting on Solar System Formation and Evolution CY NOV 03-06, 1997 CL RIO JANEIRO, BRAZIL SP Conselho Nacl Desenvolvimento Cient & Tcenolog, Fdn Amparo Pesquisa Estado Rio Janeiro, Fdn Amparo Pesquisa Estado Sao Paulo, UNESCO, Red Latino Amer Astronomia AB Models of planet formation and of the orbital stability of planetary systems are described and used to discuss possible characteristics of undiscovered planetary systems. Modern theories of star and planet formation, which are based upon observations of the Solar System and of young stars and their environments, predict that rocky planets should form in orbit about most single stars. It is uncertain whether or not gas giant planet formation is common, because most protoplanetary disks may dissipate before solid planetary cores can grow large enough to gravitationally trap substantial quantities of gas. A potential hazard to planetary systems is radial decay of planetary or bits resulting from interactions with material within the disk. Planets more massive than Earth have the potential to decay the fastest, and may be able to sweep up smaller planets in their path. The implications of the giant planets found in recent radial velocity searches for the abundances of habitable planets are discussed, and the methods that are being used and planned for detecting and characterizing extrasolar planets are reviewed. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Lissauer, JJ (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-69-4 J9 ASTR SOC P PY 1998 VL 149 BP 1 EP 11 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL75J UT WOS:000076574700001 ER PT B AU Jenniskens, P Blake, DF Kouchi, A AF Jenniskens, P Blake, DF Kouchi, A BE Schmitt, B deBergh, C Festou, M TI Amorphous water ice SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jenniskens, P (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. NR 0 TC 31 Z9 31 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 139 EP 155 PG 17 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900007 ER PT B AU Salama, F AF Salama, F BE Schmitt, B deBergh, C Festou, M TI UV photochemistry of ices - The role of photons in the processing of ices SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale AB The potential impact of UV photoprocessing on the composition and the properties of solar system ices is discussed. The various energetic processes to which solar system ices are exposed (photon irradiation and charged particle bombardement) are taken into account as well as the variation of these processes with the type of object considered (planet, satellite, comet, rings...) and its environment. An attempt is made in each case to assess the relative contribution/importance of photoinduced chemistry compared to the chemistry induced by charged particle bombardement. Thus, it is found that UV photons should dominate the processing of ices in the outer layers of the surface. This, of course, needs to be scaled to the flux of solar UV photons available in each case. The information available on the composition of solar system molecular ices is reviewed and the known/potential chemical reactions induced by photon irradiation are examined. The laboratory techniques most commonly used to simulate the photoprocessing of ices are described. The information derived from the laboratory studies of the photochemistry of planetary, cometary and interstellar ice analogs is reviewed through representative examples. It is found that the laboratory effort devoted to the study of the UV photochemistry of planetary ice analogs has been virtually nonexistent until very recently. This is in sharp contrast with the case of interstellar ices where a fair amount of information has been derived from laboratory simulations over the last two decades. This is also in sharp contrast with the effort devoted to the study of the chemistry induced in ices by ion bombardment. A similar effort (in size, scope, and continuity) is called for to study the photon induced chemistry in solar-system ices. Moreover, it is fundamentally important to study the combined effects of UV photon irradiation and ion bombardment for the processing of ices to realistically simulate the irradiation effects on solar system ices. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Salama, F (reprint author), NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 0 TC 12 Z9 12 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 259 EP 279 PG 21 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900011 ER PT B AU Johnson, TV AF Johnson, TV BE Schmitt, B deBergh, C Festou, M TI Introduction to icy satellite geology SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale AB The icy satellites have had diverse and fascinating geological histories. Each shows evidence on its surface of the action of many different processes, both endogenic and exogenic. This chapter briefly reviews the historical development of thought about satellite geology, the factors which determine the course of geologic history on a satellite, and a categorization by "metamorphic grade" of the major satellites of the outer solar system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, TV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 511 EP 523 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900021 ER PT B AU Cruikshank, DP Brown, RH Calvin, WM Roush, TL Bartholomew, MJ AF Cruikshank, DP Brown, RH Calvin, WM Roush, TL Bartholomew, MJ BE Schmitt, B deBergh, C Festou, M TI Ices on the satellites of Jupiter, Saturn, and Uranus SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale AB Three satellites of Jupiter, seven satellites of Saturn, and five satellites of Uranus show spectroscopic evidence of H2O ice on their surfaces, although other details of their surfaces are highly diverse. The icy surfaces contain contaminants of unknown composition in varying degrees of concentration, resulting in coloration and large differences in albedo. In addition to H2O, Europa has frozen SO2, and Ganymede has O-2 in the surface; in both of these cases external causes are implicated in the deposition or formation of these trace components. Similarly O-3 is found in the surface ices of Ganymede, Dione, and Rhea, probably induced by the effects of magnetospheric particles. Variations in ice exposure across the surfaces of the satellites are measured from the spectroscopic signatures. While H2O ice occurs on the surfaces of many satellites, the range of bulk densities of these bodies shows that its contribution to their overall compositions is highly variable from one object to another. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 34 Z9 34 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 579 EP 606 PG 28 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900024 ER PT B AU Cruikshank, DP Roush, TL Owen, TC Quirico, E De Bergh, C AF Cruikshank, DP Roush, TL Owen, TC Quirico, E De Bergh, C BE Schmitt, B deBergh, C Festou, M TI The surface compositions of Triton, Pluto, and Charon SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale AB Neptune's satellite Triton, and the planet-satellite binary Pluto and Charon, are the most distant planetary bodies on which ices have been directly detected. Triton and Pluto have very similar dimensions and mean densities, suggesting a similar or common origin. Through Earth-based spectroscopic observations in the near-infrared, solid N-2, CH4 H2O, and CO have been found on both bodies, with the additional molecule CO2 on Triton. N-2 dominates both surfaces, although the coverage is not spatially uniform. On Triton, the CH4 and CO are mostly or entirely frozen in the N-2 matrix, while CO2 may be spatially segregated. On Pluto, some CH4 and the CO are frozen in the N-2 matrix, but there is evidence for additional CH4 in a pure state, perhaps lying as a lag deposit on a subsurface layer of N-2. Despite their compositional and dimensional similarities, Pluto and Triton are quite different from one another in detail. Additional hydrocarbons and other volatile ices have been sought spectroscopically but have not yet been detected. The only molecule identified on Pluto's satellite Charon is solid H2O, but the spectroscopic data are of low precision and admit the presence of other ices such as CH4. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruikshank, DP (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 33 Z9 33 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 655 EP 684 PG 30 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900027 ER PT B AU Samuelson, R AF Samuelson, R BE Schmitt, B deBergh, C Festou, M TI Atmospheric ices SO SOLAR SYSTEM ICES SE ASTROPHYSICS AND SPACE SCIENCE LIBRARY LA English DT Proceedings Paper CT International Symposium on Solar System Ices CY MAR 27-30, 1995 CL TOULOUSE, FRANCE SP Lab Glaciol & Geophys Environm Grenoble, Observ Paris, Dept Rech Spatiale AB Although considerable theoretical work has led to useful models of condensate clouds in the various planetary atmospheres, this chapter emphasizes such cloud characteristics as composition and particle size that can be inferred from data more or less directly. Up to now, infrared spectroscopy has been the sole means by which the chemical constituents of condensates contained in planetary atmospheres (exclusive of the Earth) have been positively identified. Ground-based spectra were responsible for demonstrating that the clouds of Venus are composed of concentrated H2SO4. Spacecraft-borne spectrometers on Mariners 6, 7, and 9 have been instrumental in identifying CO2 and H2O ices in the atmosphere of Mars. Condensed SO2 in Io's tenuous atmosphere, and ice clouds of C4N2 and KC3N in the lower stratosphere of Titan, have been identified with the IRIS interferometer spectrometer on board the Voyager 1 spacecraft. Analyses from both Voyagers 1 and 2 that do not involve spectral absorption bands have developed strong cases for the presence of ice clouds of NH3 on Jupiter and Saturn, CH4 on Uranus and Neptune, and C2H6 On Titan. Cloud particles on Venus and Mars are small, indicating the presence of large numbers of seed nuclei acting as condensation centers, as well as a high degree of static stability, at least for the atmosphere of Venus. Moderate to large NH3 cloud particles on Jupiter suggest rapid coagulation due to atmospheric turbulence. Condensation particles of intermediate size on Titan are consistent with moderate numbers of condensation centers in a statically stable lower stratosphere. Possible supersaturation of CH4 in Titan's troposphere would lead to methane hail or rain, with a concomitant absence of stable clouds. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Samuelson, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-4902-4 J9 ASTROPHYS SPACE SC L PY 1998 VL 227 BP 749 EP 772 PG 24 WC Astronomy & Astrophysics; Geochemistry & Geophysics SC Astronomy & Astrophysics; Geochemistry & Geophysics GA BK50L UT WOS:000072382900031 ER PT J AU Frogley, MD Dunstan, DJ Palosz, W AF Frogley, MD Dunstan, DJ Palosz, W TI Combined Raman and transmission spectroscopy of ZnTe under pressure SO SOLID STATE COMMUNICATIONS LA English DT Article DE semiconductors; electronic band structure; optical; properties; phonons; strain, high pressure ID ZINC CHALCOGENIDES; PHONON-DISPERSION; DEPENDENCE; ABSORPTION; SCATTERING; GAAS AB We report measurements of both Raman and transmission spectroscopy in the same samples, under high pressure. The combination of two spectroscopies is shown to improve the reliability of the data. The phase transition is found at 940 +/- 0.2 kbar. The pressure dependence of the band gap is described by a density deformation potential of 4.90 +/- 0.15 eV, or a linear pressure coefficient of 10.2 +/- 0.3 meV kbar(-1) at ambient pressure. We find that the shifts of the LO and TO phonon energies are linear with the shift of the band gap and therefore fit to a linear dependence on density with corresponding deformation potentials of 223 +/- 3 cm(-1) (LO) and 290 +/- 3 cm(-1) (TO). (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Frogley, MD (reprint author), Univ London Queen Mary & Westfield Coll, Dept Phys, Mile End Rd, London E1 4NS, England. RI Dunstan, David/F-9830-2012 NR 21 TC 10 Z9 10 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PY 1998 VL 107 IS 10 BP 537 EP 541 DI 10.1016/S0038-1098(98)00276-2 PG 5 WC Physics, Condensed Matter SC Physics GA 106NQ UT WOS:000075136100004 ER PT J AU Ramungul, N Khemka, V Tyagi, R Chow, TP Ghezzo, M Neudeck, PG Kretchmer, J Hennessy, W Brown, DM AF Ramungul, N Khemka, V Tyagi, R Chow, TP Ghezzo, M Neudeck, PG Kretchmer, J Hennessy, W Brown, DM TI Comparison of aluminum- and boron-implanted vertical 6H-SiC P+N junction diodes SO SOLID-STATE ELECTRONICS LA English DT Article AB The electrical performance of mesa type 6H-SiC p(+)n junction diodes formed via high temperature implantation of Al-27 and B-11 has been comparatively studied and analyzed at temperatures up to 400 degrees C using the Shockley model and the space-charge-limited current model. The Al-implanted diodes show better forward current-voltage characteristics with the best ideality factor obtained at 400 degrees C of 1.6 while that for B-implanted diodes is 1.3. The factor that prohibits the forward performance of the Al-implanted diodes appears to be the deep defect center located at 1.2 eV above the valence band while that of B-implanted diodes appears to be the deep boron center called D-center located at 0.7 similar to 0.8 eV above the valence band. On the other hand, B-implanted diodes show a better yield in the reverse direction with at least an order-of-magnitude lower reverse leakage current than that of Al-implanted diodes at all measurement temperatures. Several micropipe microplasmas were plainly visible in the middle of the mesa of the Al-implanted diodes when biased at -250 V but not on boron devices. The forward voltage drop of Al-implanted diodes is tightly distributed at 2.2 V with a forward resistance of 125 Omega while that of B-implanted diodes is broadly distributed with an average value of 2.8 V and nearly 200 times larger forward resistance. (C) 1998 Elsevier Science Ltd. All rights reserved. C1 Rensselaer Polytech Inst, Troy, NY 12180 USA. GE, Corp Res & Dev, Schenectady, NY 12301 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ramungul, N (reprint author), Rensselaer Polytech Inst, Troy, NY 12180 USA. NR 11 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD JAN PY 1998 VL 42 IS 1 BP 17 EP 22 DI 10.1016/S0038-1101(97)00217-7 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA ZB120 UT WOS:000072437900002 ER PT B AU Whorton, MS Alhorn, DC AF Whorton, MS Alhorn, DC BE Galloway, RG Lokaj, S TI Microgravity vibration control and civil applications SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Controlling vibration of structures is essential for both space structures as well as terrestrial structures. Due to the ambient acceleration levels anticipated for the International Space Station, active vibration isolation is required to provide a quiescent acceleration environment for many science experiments. An overview is given of systems developed and flight tested in orbit for microgravity vibration isolation. Technology developed for vibration control of flexible space structures may also be applied to control of terrestrial structures such as buildings and bridges subject to wind loading or earthquake excitation. Recent developments in modern robust control for flexible space structures are shown to provide good structural vibration control while maintaining robustness to model uncertainties. Results of a mixed H-2/H-infinity control design are provided for a benchmark problem in earthquake engineering for building structural control. C1 NASA, George C Marshall Space Flight Ctr, ED12, Huntsville, AL 35812 USA. RP Whorton, MS (reprint author), NASA, George C Marshall Space Flight Ctr, ED12, Huntsville, AL 35812 USA. NR 10 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 37 EP 45 PG 9 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300005 ER PT B AU Hunt, JL Couch, LM AF Hunt, JL Couch, LM BE Galloway, RG Lokaj, S TI Beyond Hyper-X SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB A design/performance matrix for horizontal take-off/horizontal landing (HTHL) hypersonic airbreathing vehicles is presented. Activities and plans for enhancing and resolving the matrix are given. A Hypersonic Systems Integration Demonstrator (HySID) vehicle concept providing a technology flight testbed from M=0 to 7 is introduced. C1 NASA, Langley Res Ctr, Syst Anal Off, Hyper X Program Off, Hampton, VA 23681 USA. RP Hunt, JL (reprint author), NASA, Langley Res Ctr, Syst Anal Off, Hyper X Program Off, Hampton, VA 23681 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 151 EP 174 PG 24 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300020 ER PT B AU Friedman, R AF Friedman, R BE Galloway, RG Lokaj, S TI Fire safety in extraterrestrial environments SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Despite rigorous fire-safety policies and practices, fire incidents are possible during lunar and Martian missions. Fire behavior and hence preventive and responsive safety actions in the missions are strongly influenced by the low-gravity environments in flight and on the planetary surfaces. This paper reviews the understanding and key issues of fire safety in the missions, stressing flame spread, fire detection, suppression, and combustion performance of propellants produced from Martian resources. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Friedman, R (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 210 EP 217 PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300025 ER PT B AU Weislogel, MM AF Weislogel, MM BE Galloway, RG Lokaj, S TI Fluids management challenges in space-based systems SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc ID CONTACT-LINE; BOUNDARY; GRAVITY; SURFACE; MOTION AB The demands of fluids management in a low-gravity environment present serious challenges to the designers of such vital spacecraft elements as liquid fuel tanks, cryogen storage tanks, and systems for water recycling. A current review of technological challenges in fluids management for space-based systems is provided by Salzman (1996) concerning a selection of unresolved issues in fluids management crucial to the success of advanced space exploration. In this paper, attention is focused on isothermal capillary phenomena and the particularly nagging problems of tankage in a low-g environment: interface configurations, natural frequency, damping, and stability. The specific effects of system wettability and the moving contact line condition are briefly reviewed. Though recent results of space experiments base added significantly to our knowledge base, deficiencies in our understanding remain. These deficiencies are outlined and an effort is recommended to update the existing "catalog" of design tools and methodologies for space-based fluids systems design and development. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Weislogel, MM (reprint author), NASA, Lewis Res Ctr, MS 500-102, Cleveland, OH 44135 USA. NR 21 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 218 EP 224 PG 7 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300026 ER PT B AU Parnell, TA Watts, JW Armstrong, TW AF Parnell, TA Watts, JW Armstrong, TW BE Galloway, RG Lokaj, S TI Radiation effects and protection for Moon and Mars missions SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc ID IN-SPACE; MODEL; UPSETS; EVENTS; RATES AB Manned and robotic missions to the Earth's moon and Mars are exposed to a continuous flux of Galactic Cosmic Rays (GCR) and occasional. but intense, fluxes of Solar Energetic Particles(SEP). These natural radiations impose hazards to manned exploration, but also present some constraints to the design of robotic missions. The hazards to interplanetary flight crews and their uncertainties have been studied recently by a National Research Council Committee (Space Studies Board 1996). Considering the present uncertainty estimates, thick spacecraft shielding would be needed for manned missions, some of which could be accomplished with onboard equipment and expendables. For manned and robotic missions, the effects of radiation on electronics, sensors, and controls require special consideration in spacecraft design. This paper describes the GCR and SEP particle fluxes, secondary particles behind shielding, uncertainties in radiobiological effects and their impact on manned spacecraft design, as well as the major effects on spacecraft equipment. The principal calculational tools and considerations to mitigate the radiation effects an discussed, and work in progress to reduce uncertainties is included. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Parnell, TA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 43 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 232 EP 244 PG 13 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300028 ER PT B AU Singh, BS Sridhar, KR AF Singh, BS Sridhar, KR BE Galloway, RG Lokaj, S TI Research and technology needs for chemical processes and operations on Mars SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Utilization of extra-terrestrial resources is vital to making affordable space exploration missions a practical reality. Almost all present NASA plans and studies to explore the Moon and Mars rely heavily on the use of local resources and emphasize In-Situ Resource Utilization (ISRU) as a key enabling capability. Indigenous resources can be used in both robotic and crewed missions for enhancing the science returns, generating power and producing propellants needed for the return part of the mission. In crewed missions ISRU can also be used for construction of habitats, radiation and thermal protection shields, and generation of oxygen, water, food and other crew consumables. Achieving these goals requires an understanding of the available extra-terrestrial resources and the mining and chemical processes that will be used to generate the necessary consumables in a mass and energy efficient manner. These processes involve chemical reactions, multiphase flows, and phase change, the scaling laws for which are often not well understood even for our terrestrial environment. Focused research studies, therefore, are needed to develop models, scaling laws, and experimental data that will qualify the use of these processes for applications on the Moon and Mars (Carpenter, 1996). This paper presents an overview of some of the processes required to generate oxygen, water, and propellant and the key challenges faced by the designers and engineers for Mars missions. A companion paper on the issues related to lunar exploration is forthcoming. C1 NASA, Lewis Res Ctr, Micrograv Fluid Phys Branch, Cleveland, OH 44135 USA. RP Singh, BS (reprint author), NASA, Lewis Res Ctr, Micrograv Fluid Phys Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 10 TC 0 Z9 0 U1 1 U2 2 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 245 EP 254 PG 10 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300029 ER PT B AU Maleki, L AF Maleki, L BE Galloway, RG Lokaj, S TI Applications of advanced clocks for space navigation, and communication SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Precision clocks and frequency standards are widely used in communication and navigation systems. In navigation, time and frequency references are the parameters that determine the ultimate accuracy of position location. While clocks and frequency standards are widely used in commercial, military, and NASA satellites, the emergence of new requirements in all these arenas have pointed to the need for new classes of standards with improved performance. In particular, the success of Global Positioning System (GPS) in numerous communication and navigation applications has already led to the need for small, high performance clocks to improve the present capabilities. Furthermore, many future spacecraft systems in autonomous and or cluster configurations require advanced clocks. Applications of advanced clocks will also be crucial for position location on Mars, where it is expected that a large number of probes will be deployed, and will be monitored independently. In this paper a general discussion of the clock applications will be followed by a description of advanced clocks, and projection for their anticipated future applications. C1 CALTECH, Jet Prop Lab, Time & Frequency Syst Res Grp, Pasadena, CA 91109 USA. RP Maleki, L (reprint author), CALTECH, Jet Prop Lab, Time & Frequency Syst Res Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 260 EP 265 PG 6 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300031 ER PT B AU Noever, DA Smith, DD Sibille, L Brown, SC Cronise, RJ Lehoczky, SL AF Noever, DA Smith, DD Sibille, L Brown, SC Cronise, RJ Lehoczky, SL BE Galloway, RG Lokaj, S TI High performance materials applications to Moon/Mars missions and bases SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc ID METAL AB Two classes of material processing scenarios will feature prominently in future interplanetary exploration: in situ production using locally available materials in lunar or planetary landings and high performance structural materials which carve out a set of properties for uniquely hostile space environments. To be competitive, high performance materials must typically offer orders of magnitude improvements in thermal conductivity or insulation, deliver high strength-to-weight ratios, or provide superior durability (low corrosion and/or ablative character, e.g., in heat shields). The space-related environmental parameters of high radiation flux, low weight, and superior reliability limits many typical aerospace materials to a short list comprising high performance alloys, nanocomposites and thin-layer metal laminates (Al-Cu, Al-Ag) with typical dimensions less than the Frank-Reed-type (e.g., packing flaws or 'weak' points crystallographically) dislocation source. Extremely light weight carbon-carbon composites and carbon aerogels will be presented as novel examples which define broadened material parameters, particularly owing to their extreme thermal insulation (R-32-64) and low densities (<0.01 g/cm(3)) approaching that of air itself. Even with these low-weight payload additions, rocket thrust limits and transport costs will always place a premium on assembling as much structural and life support resources upon interplanetary, lunar, or asteroid arrival. As an example, for in situ lunar glass manufacture, solar furnaces reaching 1700 degrees C for pure silica glass manufacture in situ are compared with sol-gel technology and acid-leached ultrapure (<0.1% FeO) silica aerogel precursors. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Noever, DA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, ES-76, Huntsville, AL 35812 USA. NR 28 TC 0 Z9 0 U1 2 U2 5 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 275 EP 285 PG 11 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300033 ER PT B AU Tucker, DS Ethridge, EC AF Tucker, DS Ethridge, EC BE Galloway, RG Lokaj, S TI Processing glass fiber from Moon/Mars resources SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Processing of Lunar/Mars raw materials into usable structural and thermal components for use on a Lunar/Mars base will be essential for human habitation. One such component will be glass fiber which can be used in a number of applications. Glass fiber has been produced from two lunar soil simulants, These two materials simulate lunar mare and lunar highlands soil compositions. Short fibers containing recrystallized areas were produced from the as-received simulants. Doping the highland simulant with 8 weight percent boria yielded a material which could be spun continuously. The effects of lunar gravity on glass fiber formation were studied utilizing NASA's KC135 aircraft. Gravity was found to play a role in crystallization and final fiber diameter. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Tucker, DS (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 290 EP 300 PG 11 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300035 ER PT B AU Costes, NC Sture, S AF Costes, NC Sture, S BE Galloway, RG Lokaj, S TI A mobility concept for Martian exploration SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB Soil mechanics and geological investigations on Mars or the Moon are described herein, using a novel mobility system, designated as the "Elastic Loop Mobility System (ELMS)". ELMS was developed as a spin-off of the U.S. Lunar Roving Vehicle (LRV) which operated on the Moon during the Apollo 15, 16, and 17 Missions. Extensive testing of the ELMS, both on soft soil and on rigid obstacles, has shown that the ELMS outperforms by far both the LRV and the two unmanned, self-propelled Soviet revers, Lunokhod 1 and 2, which landed on the Moon in the western part of Mare Imbrium, aboard the spacecraft Luna 17 and 21. In this paper, examples of soil mechanics and geological investigations that can be conducted either by an unmanned, self-propelled ELMS rover, or by an ELMS attached to a Martian Lander are discussed, along with the associated instrumentation. Through such investigations, ascertaining the existence of some primitive forms of past or present life on Martian or Lunar geological formations may become possible, in addition to obtaining numerous data on the mechanical and physicochemical properties of Martian or Lunar soils along long traverses. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Costes, NC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 301 EP 318 PG 18 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300036 ER PT B AU Bentley, MT AF Bentley, MT BE Galloway, RG Lokaj, S TI Augmented & Virtual Reality payload processing SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB The following discussion outlines a few of the various applications possible utilizing Augmented Reality (AR) and Virtual Reality (VR) technology in the aerospace industry. Not only will applications be identified within payload processing, but also some additional applications unique to AR technology. Any technologies in their infancy have technical challenges, and these are no exception. A brief discussion of these challenges will be beneficial in accurately describing their current development status. This discussion is motivated by actual research initiatives that have begun at the Kennedy Space Center within the Payload Customer Outreach Office. It is intended to be an introduction to these emerging technologies, but an attempt will be made to be rigorous without having rigor mortise. Although the process is still in it's infancy, the technologies show great promise. C1 NASA, BCC, Kennedy Space Ctr, FL 32899 USA. RP Bentley, MT (reprint author), NASA, BCC, Kennedy Space Ctr, FL 32899 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 409 EP 416 PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300047 ER PT B AU Mendell, WW AF Mendell, WW BE Galloway, RG Lokaj, S TI Effect of the lunar seismic environment on a Moon-based optical interferometer SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB The European Space Agency (ESA) has studied the performance of future space-based optical interferometers. Included was an analysis of a candidate design of a lunar surface instrument with a 5-km separation between the indivdual telescopes. The report predicted that observations on the Moon would be impeded by an incessant rain of micrometorites which would disrupt interferograms approximately every 7 seconds via seismic disturbances. Examination of 8 years of data from the Apollo seismic stations shows that a disruptive seismic event from a meteorite striking the Moon should occur no more than once a year at any given site. C1 NASA, JSC, SN2, Houston, TX 77058 USA. RP Mendell, WW (reprint author), NASA, JSC, SN2, Houston, TX 77058 USA. NR 25 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 451 EP 461 PG 11 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300052 ER PT B AU Drake, BG Joosten, BK AF Drake, BG Joosten, BK BE Galloway, RG Lokaj, S TI Preparing for human exploration SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB NASA's Human Exploration and Development of Space (HEDS) Enterprise(1.2) is defining architectures and requirements for human exploration that radically reduce the costs of such missions through the use of advanced technologies, commercial partnerships and innovative systems strategies. In addition, the HEDS Enterprise is collaborating with the Space Science Enterprise to acquire needed early knowledge about Mars and to demonstrate critical technologies via robotic missions. This paper provides an overview of the technological challenges facing NASA as it prepares for human exploration. Emphasis is placed on identifying the key technologies including those which will provide the most return in terms of reducing total mission cost and/or reducing potential risk to the mission crew. Top-level requirements are provided for those critical enabling technology options currently under consideration. C1 NASA, JSC, Explorat Off, Houston, TX 77058 USA. RP Drake, BG (reprint author), NASA, JSC, Explorat Off, Houston, TX 77058 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 541 EP 554 PG 14 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300062 ER PT B AU Connolly, JF AF Connolly, JF BE Galloway, RG Lokaj, S TI Robotic precursors to human Mars missions SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc C1 NASA, JSC, Explorat Off, Houston, TX 77058 USA. RP Connolly, JF (reprint author), NASA, JSC, Explorat Off, Houston, TX 77058 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 555 EP 562 PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300063 ER PT B AU Joosten, K George, J Condon, G Hoffman, SJ AF Joosten, K George, J Condon, G Hoffman, SJ BE Galloway, RG Lokaj, S TI Continuing development of the NASA human Mars mission design SO SPACE 98 LA English DT Proceedings Paper CT 6th International Conference and Exposition on Engineering, Construction, and Operations in Space (Space 98) CY APR 26-30, 1998 CL ALBUQUERQUE, NM SP Amer Soc Civil Engineers, Aerospace Div, Sandia Natl Labs, Amer Astronaut Soc, Amer Inst Architects, NASA, Kirtland Air Force Base, Phillips Site, Air Force Res Lab, New Mexico, Wright Patterson Air Force Base, Wright Patterson Site, Ohio, Air Force Acad. Colorado Springs, Bechtel Corp, Fluor Daniel Inc AB During 1992 - 1994 work was done by personnel representing several NASA field centers to formulate a mission scenario that addresses human exploration of Mars. This scenario describes an approach for the first human missions to Mars, utilizing systems and operations that are technically feasible, have reasonable risks, and have relatively low casts. It was understood that this scenario could be improved through refinement of the analyses initially performed and by introducing new technology as that technology matured. Various analyses and trade studies have been underway at many NASA field centers since work on the initial version of the mission scenario was completed This paper briefly recaps the piloted Mars mission as originally developed to set the stage far a description of some of the work recently completed. Two topics will be highlighted: first, an aerocapture analysis illustrates the refinement of some of the initial analyses far the mission scenario; and second, an alternative technology, low thrust propulsion to perform part of the Earth departure maneuver, that appears to equal, if not improve, the overall performance of the mission architecture. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Joosten, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0339-2 PY 1998 BP 563 EP 570 PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA BM53L UT WOS:000079075300064 ER PT S AU Edelson, R Alexander, T Crenshaw, DM Kaspi, S Malkan, M Peterson, B Warwick, R AF Edelson, R Alexander, T Crenshaw, DM Kaspi, S Malkan, M Peterson, B Warwick, R BE Walker, HJ Welsh, WF Caraveo, PA Gabriel, A TI Rapid continuum variability in NGC 4151 SO SPACE BASED ASTRONOMY: ISO, AGN, RADIOPULSARS AND THE SUN SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1.3, E1.4, E1.5 and E2.3 Symposia of COSPAR Scientific Commission E on Space Based Astronomy - ISO, AGN Radiopulsars and the Sun at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Astron Union ID SHORT-TIMESCALE VARIABILITY; ACTIVE GALACTIC NUCLEI; BROAD-LINE REGION; MULTIWAVELENGTH OBSERVATIONS; ULTRAVIOLET VARIABILITY; X-RAY; NGC-5548; NGC-4151; STEPS; SIZE AB Intensive monitoring of NGC 4151 showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths. The strongest variations were seen in similar to 1.5 keV X-rays, with weaker variations at similar to 100 keV and no significant variability in the 0.1-1 keV bands, In the ultraviolet/optical regime, the fractional variability amplitude decreased from 9% to 1% as the wavelength increased from 1275 Angstrom to 6900 Angstrom. The phase differences between variations in different bands were consistent with zero lag, with upper limits of less than or similar to 0.15 day between 1275 Angstrom and the other ultraviolet bands, less than or similar to 0.3 day between 1275 Angstrom and 1.5 keV, and 1 day between 1275 Angstrom, and 5125 Angstrom, an order of magnitude improvement over limits determined in previous multi-waveband AGN monitoring campaigns. The ultraviolet fluctuation power spectra showed no evidence for periodicity, but were instead well-fitted with a very red power-law, The tight limits on the lags indicate that size of the putative reprocessing region is smaller than similar to 0.15 lt-day in size. After correcting for absorption, the X-ray luminosity variations appear adequate to drive the ultraviolet/optical variations, but energy budget and other arguments indicate that only a fraction of the total low-energy flux could be reprocessed high-energy emission. The data are also consistent with the variable emission coming from the hotter inner regions of an accretion disk and non-variable emission from the cooler outer regions. (C)1998 COSPAR. Published by Elsevier Science Ltd. C1 Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Wise Observ, IL-69978 Tel Aviv, Israel. NASA, Goddard Space Flight Ctr, Comp Sci Corp, Astron Program, Greenbelt, MD 20771 USA. Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90024 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Univ Leicester, Dept Astron, Leicester LE1 7RH, Leics, England. RP Edelson, R (reprint author), Univ Iowa, Dept Phys & Astron, 203 Van Allen Hall, Iowa City, IA 52242 USA. NR 13 TC 0 Z9 0 U1 1 U2 1 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043310-3 J9 ADV SPACE RES PY 1998 VL 21 IS 1-2 BP 77 EP 81 DI 10.1016/S0273-1177(97)00616-9 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK61F UT WOS:000072736800010 ER PT S AU Harding, AK Daugherty, JK AF Harding, AK Daugherty, JK BE Walker, HJ Welsh, WF Caraveo, PA Gabriel, A TI Pulse profiles and spectra of gamma ray pulsars in the polar cap model SO SPACE BASED ASTRONOMY: ISO, AGN, RADIOPULSARS AND THE SUN SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1.3, E1.4, E1.5 and E2.3 Symposia of COSPAR Scientific Commission E on Space Based Astronomy - ISO, AGN Radiopulsars and the Sun at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Astron Union ID CASCADES; EMISSION AB We investigate predictions for pulse profiles and spectra of gamma-ray pulsars in the polar cap curvature radiation-initiated cascade model. In this model, the gamma-ray beam is a hollow cone centered on the magnetic pole, producing either double-peaked or single-peaked pulse profiles depending on observer orientation. We have computed simulated distributions of pulse peak phase separation seen by observers at random orientation as a function of gamma-ray beam width and obliquity distribution. The observed distribution of pulse peak phase separation, which favors double-peaked pulses with phase separation near 0.4, can be matched assuming that most gamma-ray pulsars have obliquity < 45(0) and beam opening angles of around 30(0). The gamma-ray spectra result from primary particle curvature radiation, softened by synchrotron radiation from one or more generations of electron-positron pairs. We have determined the generation number and predicted spectral index of gamma-ray pulsar cascades as a function of period and surface magnetic field. It is found that the spectral hardness should decrease with cascade generation number and increase with characteristic age, a trend observed for EGRET-detected pulsars. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ N Carolina, Dept Comp Sci, Asheville, NC 28804 USA. RP Harding, AK (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Harding, Alice/D-3160-2012 NR 9 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043310-3 J9 ADV SPACE RES PY 1998 VL 21 IS 1-2 BP 251 EP 254 DI 10.1016/S0273-1177(97)00811-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK61F UT WOS:000072736800032 ER PT S AU Davila, JM AF Davila, JM BE Walker, HJ Welsh, WF Caraveo, PA Gabriel, A TI Observing the inner Heliosphere from new perspectives SO SPACE BASED ASTRONOMY: ISO, AGN, RADIOPULSARS AND THE SUN SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1.3, E1.4, E1.5 and E2.3 Symposia of COSPAR Scientific Commission E on Space Based Astronomy - ISO, AGN Radiopulsars and the Sun at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Astron Union AB In the solar corona, the density scale height is large, a considerable fraction of a solar radius. Because of this, observations of the Sun from a single vantage point produce images which show an unavoidable overlapping of many structures along the line of sight. This makes it difficult, and sometimes impossible, to determine the true nature of the feature being observed. This difficulty can be overcome by obtaining simultaneous observations from multiple vantage points. Using these observations, and a reconstructions process similar to that used in medical imaging applications, the true three-dimensional nature of the solar corona can be deduced. The same process can be used to follow the formation of coronal mass ejections (CME's) in the low corona and the propagation of CME's through interplanetary space. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Davila, JM (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043310-3 J9 ADV SPACE RES PY 1998 VL 21 IS 1-2 BP 319 EP 323 DI 10.1016/S0273-1177(97)00988-5 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK61F UT WOS:000072736800041 ER PT S AU Chupp, EL Aprile, E Bertsch, DL Dunphy, PP Ramaty, R AF Chupp, EL Aprile, E Bertsch, DL Dunphy, PP Ramaty, R BE Walker, HJ Welsh, WF Caraveo, PA Gabriel, A TI Future high energy solar missions (imaging > 20 MEV neutral flare emissions) SO SPACE BASED ASTRONOMY: ISO, AGN, RADIOPULSARS AND THE SUN SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1.3, E1.4, E1.5 and E2.3 Symposia of COSPAR Scientific Commission E on Space Based Astronomy - ISO, AGN Radiopulsars and the Sun at the 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, European Space Agcy, Inst Space & Astronaut Sci, Int Astron Union ID GAMMA-RAY OBSERVATIONS; 1982 JUNE 3; HARD X-RAY; TELESCOPE; PARTICLES; TPC AB A recurring fundamental problem in astrophysics is to determine how the Sun can accelerate ions to energies as high as 30 GeV and electrons to possibly comparable energies in a time scale of seconds. Direct evidence for the interactions of these particles with the solar atmosphere is revealed by the observation of pion decay gamma rays, bremsstrahlung >200 MeV and neutrons >50 MeV, as well as by the neutron events observed by ground level detectors on the Earth. Secondary evidence comes from the observation of the hare related solar energetic particles (SEP) observed in space. However, the sites of acceleration and interaction of these charged particles in the the solar atmosphere is completely unknown. Even though the site of acceleration and interaction of the electrons producing the hard X-ray bremsstrahlung is known from imaging experiments such as the HXT on Yohkoh this result cannot a priori be assumed to be the case for the ions and ultrarelativistic electrons. This paper describes two techniques which will locate the emission regions of high-energy neutral emissions to arcminute or better spatial accuracy and also determine their energy spectra. Such an observation for even one hare would be a definitive advance for understanding solar flare particle acceleration. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 Univ New Hampshire, Inst Study Earth Oceans & Space, Dept Phys, Durham, NH 03824 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Ctr Space Sci, Durham, NH 03824 USA. Columbia Univ, Dept Phys, New York, NY 10022 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Chupp, EL (reprint author), Univ New Hampshire, Inst Study Earth Oceans & Space, Dept Phys, Durham, NH 03824 USA. NR 32 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043310-3 J9 ADV SPACE RES PY 1998 VL 21 IS 1-2 BP 333 EP 342 DI 10.1016/S0273-1177(97)00991-5 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BK61F UT WOS:000072736800044 ER PT J AU Lesh, JR AF Lesh, JR TI Overview of the NASA/JPL lasercom program SO SPACE COMMUNICATIONS LA English DT Article AB The NASA-funded optical communications program being conducted at JPL is described. The spacecraft transceiver terminal developments, a test infrastructure for assessing the performance of future space terminals, an atmospheric visibility monitoring program, some recent systems-level demonstrations, and a communications technology roadmap for planetary missions over the next 25 years are presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lesh, JR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 1 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 1998 VL 15 IS 2 BP 65 EP 70 PG 6 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 164PV UT WOS:000078473500001 ER PT J AU Wilson, KE Lesh, JR Araki, K Arimoto, Y AF Wilson, KE Lesh, JR Araki, K Arimoto, Y TI Overview of the ground-to-orbit lasercom demonstration SO SPACE COMMUNICATIONS LA English DT Article AB The Ground-to-Orbit Lasercom Demonstration conducted between the ETS-VI spacecraft and the ground station at JPL's Table Mountain Facility, Wrightwood CA was the first ground-to-space two-way optical communications experiment. The demonstration was conducted over a period of seven months and required simultaneous and cooperative operations by team members in Tokyo and California. A key objective was to measure the atmospheric attenuation and seeing during the demonstration to evaluate the performance of the optical link. The optical downlink telemetry provided information on the in-orbit performance of ETS-VI's laser communications equipment. Downlinked PN data enabled measurement of bit-error rates. BERs as low as 10(-4) were measured on the uplink and 10(-5) on the downlink. Measured signal powers (corrected for measured atmospheric attenuation) agreed with theoretical predictions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. Commun Res Lab, Koganei, Tokyo, Japan. RP Wilson, KE (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RI Institute of Chemistry - USP, Dept. of Chemistry/B-8988-2012 NR 7 TC 11 Z9 12 U1 0 U2 4 PU IOS PRESS PI AMSTERDAM PA VAN DIEMENSTRAAT 94, 1013 CN AMSTERDAM, NETHERLANDS SN 0924-8625 J9 SPACE COMMUN JI Space Commun. PY 1998 VL 15 IS 2 BP 89 EP 95 PG 7 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 164PV UT WOS:000078473500005 ER PT S AU Niemann, HB Atreya, SK Carignan, GR Donahue, TM Haberman, JA Harpold, DN Hartle, RE Hunten, DM Kasprzak, WT Mahaffy, PR Owen, TC Spencer, NW AF Niemann, HB Atreya, SK Carignan, GR Donahue, TM Haberman, JA Harpold, DN Hartle, RE Hunten, DM Kasprzak, WT Mahaffy, PR Owen, TC Spencer, NW BE Matson, DL Thomas, N Lamy, P TI Chemical composition measurements of the atmosphere of Jupiter with the Galileo Probe mass spectrometer SO SPACE EXPLORATION OF THE OUTER SPACE SOLAR SYSTEM AND COMETARY NUCLEI SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO 2 and BO 6 Symposia of COSPAR Scientific Commission B on Space Exploration of the Outer Space Solar System and Cometary Nuclei, 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, European Space Agcy, European Geophys Soc AB The Galileo Probe entered the atmosphere of Jupiter on December 7, 1995. Measurements of the chemical and isotopic composition of the Jovian atmosphere were obtained by the mass spectrometer during the descent over the 0.5 to 21 bar pressure region over a time period of approximately 1 hour. The sampling was either of atmospheric gases directly introduced into the ion source of the mass spectrometer through capillary leaks or of gas, which had been chemically processed to enhance the sensitivity of the measurement to trace species or noble gases. The analysis of this data set continues to be refined based on supporting laboratory studies on an engineering unit, The mixing ratios of the major constituents of the atmosphere hydrogen and helium have been determined as well as mixing ratios or upper limits for several less abundant species including: methane, water, ammonia, ethane, ethylene, propane, hydrogen sulfide, neon, argon, krypton, and xenon. Analysis also suggests the presence of trace levels of other 3 and 4 carbon hydrocarbons, or carbon and nitrogen containing species, phosphine, hydrogen chloride, and of benzene. The data set also allows upper limits to be set for many species of interest which were not detected. Isotope ratios were measured for He-3/He-4, D/H, C-13/C-12, Ne-20/Ne-22, Ar-38/Ar-36 and for isotopes of both Kr and Xe. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Niemann, HB (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Mahaffy, Paul/E-4609-2012; Harpold, Dan/I-3345-2013 NR 9 TC 8 Z9 9 U1 2 U2 6 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1998 VL 21 IS 11 BP 1455 EP 1461 DI 10.1016/S0273-1177(98)00019-2 PG 7 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL31X UT WOS:000075095600001 PM 11541457 ER PT S AU Cooper, JF Sittler, EC Maurice, S Mauk, BH Selesnick, RS AF Cooper, JF Sittler, EC Maurice, S Mauk, BH Selesnick, RS BE Matson, DL Thomas, N Lamy, P TI Local time asymmetry of drift shells for energetic electrons in the middle magnetosphere of Saturn SO SPACE EXPLORATION OF THE OUTER SPACE SOLAR SYSTEM AND COMETARY NUCLEI SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO 2 and BO 6 Symposia of COSPAR Scientific Commission B on Space Exploration of the Outer Space Solar System and Cometary Nuclei, 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, European Space Agcy, European Geophys Soc ID INNER MAGNETOSPHERE; PLASMA; VOYAGER-1; FIELD AB Saturn encounter trajectories of Pioneer 11, Voyager 1, and Voyager 2 passed through the noon-dusk quadrant of the middle magnetosphere during approach and through dawn-midnight outbound. Intensities of energetic electrons (greater than or equal to 0.6 MeV) were an order of magnitude higher inbound than outbound at 6-15 R-S, even though the same (Pioneer 11) or higher (Voyager 1 and 2) intensities were expected outbound for stably trapped electrons with azimuthally symmetric distributions. Explanations include electron drift shell asymmetry arising from (1) magnetopause compression by the solar wind and/or (2) dusk-to-dawn electric field associated with solar wind driven convection within the magnetosphere. Theoretical and numerical calculations indicate that maximum effects of the electric field are expected at L-dependent drift resonance energies in the range of the maximum observed asymmetries. Maximum intensities would then be expected on the dusk side of the middle magnetosphere where "bannana"-shaped drift shells are expected near the resonance energies. Since some of the asymmetric drift shells would not extend around to the dawn side, minimum intensities would be expected there as observed. Further analysis and modeling will be needed to assess the relative effects of the electric field magnetopause compression, and other possible causes, Full local time coverage of energetic particles by the Cassini Orbiter mission would be invaluable for additional constraints on the magnetospheric electric and magnetic fields. (C) 1998 COSPAR, Published by Elsevier Science Ltd. C1 NASA, Hughes STX Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. RP Cooper, JF (reprint author), NASA, Hughes STX Corp, Goddard Space Flight Ctr, Code 632, Greenbelt, MD 20771 USA. RI Cooper, John/D-4709-2012; Mauk, Barry/E-8420-2017 OI Mauk, Barry/0000-0001-9789-3797 NR 23 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1998 VL 21 IS 11 BP 1479 EP 1482 DI 10.1016/S0273-1177(98)00022-2 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL31X UT WOS:000075095600005 ER PT S AU Neugebauer, M Bibring, JP AF Neugebauer, M Bibring, JP BE Matson, DL Thomas, N Lamy, P TI Champollion SO SPACE EXPLORATION OF THE OUTER SPACE SOLAR SYSTEM AND COMETARY NUCLEI SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO 2 and BO 6 Symposia of COSPAR Scientific Commission B on Space Exploration of the Outer Space Solar System and Cometary Nuclei, 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, European Space Agcy, European Geophys Soc AB At the time of the 1996 COSPAR meeting, the US NASA and the French CNES were planning to develop a comet lander as part of the International Rosetta Mission. This lander, named Champollion after the translator of the Rosetta stone, was to be released from the orbiter and landed on Comet P/Wirtanen to perform in situ analyses of the cometary nucleus. The investigations on Champollion focused on objectives that could not be performed from the Rosetta orbiter. Unfortunately, in September, 1996, NASA withdrew its support for Champollion, forcing its cancellation. The description provided in this paper is therefore principally of historical interest, but might prove useful to the development of the remaining Rosetta Lander. The instruments on Champollion would have determined the elemental, molecular, mineralogical, and isotopic compositions of material down to depths approaching 1 m below the surface of the nucleus. The physical structure of the nucleus would have been determined through measurements of the near-surface strength, density, texture, porosity, ice phases, and thermal properties. Images were to have been obtained at resolutions ranging from 1 m to 5 mu m Some key features of the lander were its actively controlled descent from the orbiter to the comet nucleus, its 2.5-m spike which served as an anchor, and the high degree of integration of the instruments with the lander structure and subsystems. The lander was powered by primary batteries. The nominal lifetime of the lander on the surface of the comet was 84 hours, during which measurement sequences could be repeated if necessary and subsurface samples could be obtained from at least three different depths. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Astrophys Spatiale, Orsay, France. RP Neugebauer, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1998 VL 21 IS 11 BP 1567 EP 1575 DI 10.1016/S0273-1177(97)00950-2 PG 9 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL31X UT WOS:000075095600014 ER PT S AU Kofman, W Barbin, Y Klinger, J Levasseur-Regourd, AC Barriot, JP Herique, A Hagfors, T Nielsen, E Grun, E Edenhofer, P Kochan, H Picardi, G Seu, R van Zyl, J Elachi, C Melosh, J Veverka, J Weissman, P Svedhem, LH Hamran, SE Williams, IP AF Kofman, W Barbin, Y Klinger, J Levasseur-Regourd, AC Barriot, JP Herique, A Hagfors, T Nielsen, E Grun, E Edenhofer, P Kochan, H Picardi, G Seu, R van Zyl, J Elachi, C Melosh, J Veverka, J Weissman, P Svedhem, LH Hamran, SE Williams, IP BE Matson, DL Thomas, N Lamy, P TI Comet nucleus sounding experiment by radiowave transmission SO SPACE EXPLORATION OF THE OUTER SPACE SOLAR SYSTEM AND COMETARY NUCLEI SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO 2 and BO 6 Symposia of COSPAR Scientific Commission B on Space Exploration of the Outer Space Solar System and Cometary Nuclei, 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, European Space Agcy, European Geophys Soc AB We describe the radio science experiment proposed for the Rosetta cometary mission. The experiment consists in the transmission of electromagnetic waves between the landers and the orbiter through the comet to study its internal structure. In the paper, the electromagnetic model of the comet is presented and used to evaluate the potentiality of the experiment. Various modellings of the radio wave propagation are discussed. Finally, a description of the experiment and the instrument is made. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 Ctr Etud Phenomenes Aleatoires & Geophys, F-38402 St Martin Dheres, France. CNRS, Serv Aeron, F-91371 Verrieres Buisson, France. Lab Glaciol & Geophys Environm, F-38402 St Martin Dheres, France. Ctr Natl Etud Spatiales, GRGS, GTP, F-31055 Toulouse, France. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Max Planck Inst Kernphys, D-69029 Heidelberg, Germany. Ruhr Univ Bochum, Inst High Frequency Tech, D-44780 Bochum, Germany. DLR, Inst Raumsimulat, D-51147 Koln, Germany. IFOCOM, I-00184 Rome, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Cornell Univ, Ithaca, NY USA. European Space Agcy, Estec, Dept Space Sci, Solar Syst Div, NL-2200 AG Noordwijk, Netherlands. PFM, Environm Surveillance Technol Program, N-2001 Lillestrom, Norway. Univ London Queen Mary & Westfield Coll, Astron Unit, London E1 4NS, England. RP Kofman, W (reprint author), Ctr Etud Phenomenes Aleatoires & Geophys, BP 46, F-38402 St Martin Dheres, France. RI Kofman, Wlodek/C-4556-2008; Herique, Alain/E-7210-2017; OI Herique, Alain/0000-0003-3699-883X; Williams, Iwan Prys/0000-0002-8069-1344 NR 17 TC 43 Z9 43 U1 0 U2 2 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1998 VL 21 IS 11 BP 1589 EP 1598 DI 10.1016/S0273-1177(97)00952-6 PG 10 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL31X UT WOS:000075095600017 ER PT S AU Cooper, JF Christian, ER Johnson, RE AF Cooper, JF Christian, ER Johnson, RE BE Matson, DL Thomas, N Lamy, P TI Heliospheric cosmic ray irradiation of Kuiper belt comets SO SPACE EXPLORATION OF THE OUTER SPACE SOLAR SYSTEM AND COMETARY NUCLEI SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT BO 2 and BO 6 Symposia of COSPAR Scientific Commission B on Space Exploration of the Outer Space Solar System and Cometary Nuclei, 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astron Union, European Space Agcy, European Geophys Soc ID SHOCK; ACCELERATION; HELIOPAUSE; MODULATION; HYAKUTAKE; SPECTRUM; ORIGIN; CRUST; MODEL; DRIFT AB Irradiation by galactic cosmic ray particles at energies above 0.1 GeV has been shown to be a significant source of energy for chemical modification of ices in Oort Cloud comets. However, these ions have minimal efficiency for surface modification, since their energy is deposited over depths of many meters, and they must act over the lifetime of the Solar System to produce an appreciable radiation-induced mantle. Recent measurements by the Voyager and Pioneer spacecraft, now moving outward from the Sun beyond 40 - 60 A.U. into the Kuiper belt region, have found a radially increasing intensity of the "anomalous" cosmic :ray component, consisting of interstellar hydrogen and heavier ions accelerated at energies up to 10(2) MeV/nucleon at the solar wind termination shock at 65 - 100 A.U. from the Sun. Significant intensities of the anomalous cosmic ray ions are expected throughout the inner Kuiper belt region beyond the termination shock and out to the heliopause. These ions would significantly affect mantle formation on Kuiper Belt comets at column depths less than 10 grams/cm(2) in the outer surface layer of material accessible to direct and remote sensing measurements. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Hughes STX Corp, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, USRA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Dept Engn Phys, Charlottesville, VA 22901 USA. RP Cooper, JF (reprint author), NASA, Hughes STX Corp, Goddard Space Flight Ctr, Code 632, Greenbelt, MD 20771 USA. RI Cooper, John/D-4709-2012; Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 26 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 J9 ADV SPACE RES PY 1998 VL 21 IS 11 BP 1611 EP 1614 DI 10.1016/S0273-1177(97)00956-3 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BL31X UT WOS:000075095600021 ER PT J AU Stone, EC Frandsen, AM Mewaldt, RA Christian, ER Margolies, D Ormes, JF Snow, F AF Stone, EC Frandsen, AM Mewaldt, RA Christian, ER Margolies, D Ormes, JF Snow, F TI The Advanced Composition Explorer SO SPACE SCIENCE REVIEWS LA English DT Review AB The Advanced Composition Explorer was launched August 25, 1997 carrying six high-resolution spectrometers that measure the elemental, isotopic, and ionic charge-state composition of nuclei from H to Ni (1 less than or equal to Z less than or equal to 28) from solar wind energies (similar to 1 keV nucl(-1)) to galactic cosmic-ray energies (similar to 500 MeV nucl(-1)). Data from these instruments is being used to measure and compare the elemental and isotopic composition of the solar corona, the nearby interstellar medium, and the Galaxy, and to study particle acceleration processes that occur in a wide range of environments. ACE also carries three instruments that provide the heliospheric context for ion composition studies by monitoring the state of the interplanetary medium. From its orbit about the Sun-Earth libration point similar to 1.5 million km sunward of Earth, ACE also provides real-time solar wind measurements to NOAA for use in forecasting space weather. This paper provides an introduction to the ACE mission, including overviews of the scientific goals and objectives, the instrument payload, and the spacecraft and ground systems. C1 CALTECH, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stone, EC (reprint author), CALTECH, Pasadena, CA 91125 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 22 TC 461 Z9 464 U1 2 U2 13 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1998 VL 86 IS 1-4 BP 1 EP 22 DI 10.1023/A:1005082526237 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 191AW UT WOS:000079999900002 ER PT J AU Stone, EC Cohen, CMS Cook, WR Cummings, AC Gauld, B Kecman, B Leske, RA Mewaldt, RA Thayer, MR Dougherty, BL Grumm, RL Milliken, BD Radocinski, RG Wiedenbeck, ME Christian, ER Shuman, S Trexel, H Von Rosenvinge, TT Binns, WR Crary, DJ Dowkontt, P Epstein, J Hink, PL Klarmann, J Lijowski, M Olevitch, MA AF Stone, EC Cohen, CMS Cook, WR Cummings, AC Gauld, B Kecman, B Leske, RA Mewaldt, RA Thayer, MR Dougherty, BL Grumm, RL Milliken, BD Radocinski, RG Wiedenbeck, ME Christian, ER Shuman, S Trexel, H Von Rosenvinge, TT Binns, WR Crary, DJ Dowkontt, P Epstein, J Hink, PL Klarmann, J Lijowski, M Olevitch, MA TI The Cosmic-Ray Isotope Spectrometer for the Advanced Composition Explorer SO SPACE SCIENCE REVIEWS LA English DT Review ID ACE MISSION; NUCLEI; PARTICLES; DETECTORS; SILICON; CALIBRATION; TELESCOPE; ELEMENTS; SOLAR AB The Cosmic-Ray Isotope Spectrometer is designed to cover the highest decade of the Advanced Composition Explorer's energy interval, from similar to 50 to similar to 500 MeV nucl(-1), with isotopic resolution for elements from Z similar or equal to 2 to Z similar or equal to 30. The nuclei detected in this energy interval are predominantly cosmic rays originating in our Galaxy. This sample of galactic matter can be used to investigate the nucleosynthesis of the parent material. as well as fractionation, acceleration, and transport processes that these particles undergo in the Galaxy and in the interplanetary medium. Charge and mass identification with CRIS is based on multiple measurements of dE/dx and total energy in stacks of silicon detectors, and trajectory measurements in a scintillating optical fiber trajectory (SOFT) hodoscope. The instrument has a geometrical factor of similar or equal to r250 cm(2) sr for isotope measurements, and should accumulate similar to 5 x 10(6) stopping heavy nuclei (Z > 2) in two years of data collection under solar minimum conditions. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Washington Univ, St Louis, MO 63130 USA. RP Stone, EC (reprint author), CALTECH, Pasadena, CA 91125 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 49 TC 90 Z9 90 U1 1 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1998 VL 86 IS 1-4 BP 285 EP 356 DI 10.1023/A:1005075813033 PG 72 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 191AW UT WOS:000079999900015 ER PT J AU Stone, EC Cohen, CMS Cook, WR Cummings, AC Gauld, B Kecman, B Leske, RA Mewaldt, RA Thayer, MR Dougherty, BL Grumm, RL Milliken, BD Radocinski, RG Wiedenbeck, ME Christian, ER Shuman, S Von Rosenvinge, TT AF Stone, EC Cohen, CMS Cook, WR Cummings, AC Gauld, B Kecman, B Leske, RA Mewaldt, RA Thayer, MR Dougherty, BL Grumm, RL Milliken, BD Radocinski, RG Wiedenbeck, ME Christian, ER Shuman, S Von Rosenvinge, TT TI The Solar Isotope Spectrometer for the Advanced Composition Explorer SO SPACE SCIENCE REVIEWS LA English DT Review ID ANOMALOUS COSMIC-RAYS; ENERGETIC PARTICLES; ABUNDANCES; NUCLEI; HELIOSPHERE; COMPONENT; SILICON; FLARES; DETECTORS; ELEMENTS AB The Solar Isotope Spectrometer (SIS), one of nine instruments on the Advanced Composition Explorer (ACE), is designed to provide high-resolution measurements of the isotopic composition of energetic nuclei from He to Zn (Z = 2 to 30) over the energy range from similar to 10 to similar to 100 MeV nucl(-1). During large solar events SIS will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona and to study particle acceleration processes. During solar quiet times SIS will measure the isotopes of low-energy cosmic rays from the Galaxy and isotopes of the anomalous cosmic-ray component, which originates in the nearby interstellar medium. SIS has two telescopes composed of silicon solid-state detectors that provide measurements of the nuclear charge, mass, and kinetic energy of incident nuclei. Within each telescope, particle trajectories are measured with a pair of two-dimensional silicon-strip detectors instrumented with custom, very large-scale integrated (VLSI) electronics to provide both position and energy-loss measurements. SIS was especially designed to achieve excellent mass resolution under the extreme, high flux conditions encountered in large solar particle events. It provides a geometry factor of similar to 40 cm(2) sr, significantly greater than earlier solar particle isotope spectrometers. A microprocessor controls the instrument operation, sorts events into prioritized buffers on the basis of their charge, range, angle of incidence, and quality of trajectory determination, and formats data for readout by the spacecraft. This paper describes the design and operation of SIS and the scientific objectives that the instrument will address. C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stone, EC (reprint author), CALTECH, Pasadena, CA 91125 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 52 TC 153 Z9 154 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1998 VL 86 IS 1-4 BP 357 EP 408 DI 10.1023/A:1005027929871 PG 52 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 191AW UT WOS:000079999900016 ER PT J AU Smith, CW L'Heureux, J Ness, NF Acuna, MH Burlaga, LF Scheifele, J AF Smith, CW L'Heureux, J Ness, NF Acuna, MH Burlaga, LF Scheifele, J TI The ACE magnetic fields experiment SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND; COSMIC-RAY; INTERPLANETARY SHOCKS; FLUCTUATIONS; TURBULENCE; EVOLUTION; WAVES; MODULATION AB The magnetic field experiment on ACE provides continuous measurements of the local magnetic field in the interplanetary medium. These measurements are essential in the interpretation of simultaneous ACE observations of energetic and thermal particles distributions. The experiment consists of a pair of twin, boom-mounted, triaxial fluxgate sensors which are located 165 inches (= 4.19 m) from the center of the spacecraft on opposing solar panels. The electronics and digital processing unit (DPU) is mounted on the top deck of the spacecraft. The two triaxial sensors provide a balanced, fully redundant vector instrument and permit some enhanced assessment of the spacecraft's magnetic field. The instrument provides data for Browse and high-level products with between 3 and 6 vector s(-1) resolution for continuous coverage of the: interplanetary magnetic field. Two high-resolution snapshot buffers each hold 297 s of 24 vector s(-1) data while on-board Fast Fourier Transforms extend the continuous data to 12 Hz resolution. Real-time observations with 1-s resolution are provided continuously to the Space Environmental Center (SEC) of the National Oceanographic and Atmospheric Association (NOAA) for near-instantaneous, world-wide dissemination in service to space weather studies. As has been our team's tradition, high instrument reliability is obtained by the use of fully redundant systems and extremely conservative designs. We plan studies of the interplanetary medium in support of the fundamental goals of the ACE mission and cooperative studies with other ACE investigators using the combined ACE dataset as well as other ISTP spacecraft involved in the general program of Sun-Earth Connections. C1 Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, CW (reprint author), Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. NR 38 TC 671 Z9 672 U1 4 U2 16 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PY 1998 VL 86 IS 1-4 BP 613 EP 632 DI 10.1023/A:1005092216668 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 191AW UT WOS:000079999900022 ER PT J AU Reames, DV AF Reames, DV TI Solar energetic particles: Sampling coronal abundances SO SPACE SCIENCE REVIEWS LA English DT Review ID ACCELERATION; FLARES; HYDROGEN; CHARGE; SHOCKS; EVENTS; IRON; IONS AB In the large solar energetic particle (SEP) events, coronal mass ejections (CMEs) drive shock waves out through the corona that accelerate elements of the ambient material to MeV energies in a fairly democratic, temperature-independent manner. These events provide the most complete source of information on element abundances in the corona. Relative abundances of 22 elements from H through Zn display the well-known dependence on the first ionization potential (FIP) that distinguishes coronal and photospheric material. For most elements, the main abundance variations depend upon the gyrofrequency, and hence on the charge-to-mass ratio, Q/A, of the ion. Abundance variations in the dominant species, H and He, are not Q/A dependent, presumably because of nonlinear wave-particle interactions of H and He during acceleration. Impulsive flares provide a different sample of material that confirms the Ne:Mg:Si and He/C abundances in the corona. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM reames@lheavx.gsfc.nasa.gov NR 37 TC 74 Z9 74 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PY 1998 VL 85 IS 1-2 BP 327 EP 340 DI 10.1023/A:1005123121972 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 149ZF UT WOS:000077636600030 ER PT J AU Suess, ST Phillips, JL MaCcomas, DJ Goldstein, BE Neugebauer, M Nerney, S AF Suess, ST Phillips, JL MaCcomas, DJ Goldstein, BE Neugebauer, M Nerney, S TI The solar wind - Inner heliosphere SO SPACE SCIENCE REVIEWS LA English DT Review DE solar wind; heliosphere; Ulysses; SOHO; MHD waves; turbulence ID FLUX-TUBE DIVERGENCE; ULYSSES OBSERVATIONS; PLASMA OBSERVATIONS; LATITUDES; SPEED AB The solar wind in the inner heliosphere, inside similar to 5 AU, has been almost fully characterized by the addition of the high heliographic latitude Ulysses mission to the many low latitude inner heliosphere missions that preceded it. The two major omissions are the high latitude solar wind at solar maximum, which will be measured during the second Ulysses polar passages, and the solar wind near the Sun, which could be analyzed by a Solar Probe mission. Here, existing knowledge of the global solar wind in the inner heliosphere is summarized in the context of the new results from Ulysses. C1 NASA, George C Marshall Space Flight Ctr, Solar Phys Branch ES82, Huntsville, AL 35812 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ohio Univ, Lancaster, OH 43130 USA. RP NASA, George C Marshall Space Flight Ctr, Solar Phys Branch ES82, Huntsville, AL 35812 USA. NR 23 TC 11 Z9 11 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JAN PY 1998 VL 83 IS 1-2 BP 75 EP 86 DI 10.1023/A:1005069328058 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU056 UT WOS:000074156800008 ER PT J AU Burlaga, LF Ness, NF AF Burlaga, LF Ness, NF TI Voyager observations of the magnetic field in the distant heliosphere SO SPACE SCIENCE REVIEWS LA English DT Review ID MERGED INTERACTION REGIONS; COSMIC-RAY MODULATION; SOLAR-WIND; SECTOR STRUCTURE; PICKUP PROTONS; EVOLUTION; ULYSSES; SHOCK AB The latitudinal structure of the heliospheric magnetic field during much of the solar cycle is determined by a "sector zone", in which both positive and negative magnetic polarities are observed, and by the unipolar regions above and below the sector zone. Distinct corotating streams and interactions regions are found primarily in the sector zone during the declining phase of the solar cycle. Within a few AU, the streams and interaction regions are distinct and are related to solar features. A restructuring of the solar wind occurs between 1 AU and approximate to 15 AU, in which the isolated streams, interaction regions and shocks merge to form compound streams and merged interaction regions ("MIRs"). Memory of the source conditions is lost in this process. In the region between approximate to 30 AU and the termination shock (the "distant heliosphere"), the pressure of interstellar pickup protons dominates that of the magnetic field and solar wind particles and largely controls the dynamical processes. During 1983 and 1994, corotating streams and corotating interaction regions were observed at 1 AU. Merged interaction regions were observed at approximate to 15 AU in 1983, but not at approximate to 45 AU during 1994. This result suggests a further restructuring of the solar wind in the distant heliosphere, but variations from one solar cycle to the next might also contribute to the result. Approaching solar minimum in 1996, the latitudinal extent of the sector zone decreased, and Voyager 2 gradually entered the unipolar region below it. The speed was lower in the sector zone than below it. At Voyagers 1 and 2, the change in cosmic ray intensity is related to the magnetic field strength during each year from 1983 through 1996. The magnetic field strength has a multifractal distribution throughout the heliosphere. This fundamental symmetry of the heliosphere has not been incorporated explicitly in cosmic ray propagation models. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 692, Greenbelt, MD 20771 USA. NR 35 TC 17 Z9 17 U1 1 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JAN PY 1998 VL 83 IS 1-2 BP 105 EP 121 DI 10.1023/A:1005025613036 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU056 UT WOS:000074156800011 ER PT J AU Fisk, LA Wenzel, KP Balogh, A Burger, RA Cummings, AC Evenson, P Heber, B Jokipii, JR Krainev, MB Kota, J Kunow, H Le Roux, JA McDonald, FB McKibben, RB Potgieter, MS Simpson, JA Steenberg, CD Suess, S Webber, WR Wibberenz, G Zhang, M Ferrando, P Fujii, Z Lockwood, JA Moraal, H Stone, EC AF Fisk, LA Wenzel, KP Balogh, A Burger, RA Cummings, AC Evenson, P Heber, B Jokipii, JR Krainev, MB Kota, J Kunow, H Le Roux, JA McDonald, FB McKibben, RB Potgieter, MS Simpson, JA Steenberg, CD Suess, S Webber, WR Wibberenz, G Zhang, M Ferrando, P Fujii, Z Lockwood, JA Moraal, H Stone, EC TI Global processes that determine cosmic ray modulation - Report of Working Group 1 SO SPACE SCIENCE REVIEWS LA English DT Review ID HELIOSPHERIC MAGNETIC-FIELD; MERGED INTERACTION REGIONS; WIND TERMINATION SHOCK; SOUTH POLAR PASS; SOLAR MODULATION; ULYSSES OBSERVATIONS; RADIAL GRADIENTS; DRIFT MODEL; TRANSPORT; TIME AB The global processes that determine cosmic ray modulation are reviewed. The essential elements of the theory which describes cosmic ray behavior in the heliosphere are summarized, and a series of discussions is presented which compare the expectations of this theory with observations of the spatial and temporal behavior of both galactic cosmic rays and the anomalous component; the behavior of cosmic ray electrons and ions; and the 26-day variations in cosmic rays as a function of heliographic latitude. The general conclusion is that the current theory is essentially correct. There is clear evidence, in solar minimum conditions, that the cosmic rays and the anomalous component behave as is expected from theory, with strong effects of gradient and curvature drifts. There is strong evidence of considerable latitude transport of the cosmic rays, at all energies, but the mechanism by which this occurs is unclear. Despite the apparent success of the theory, there is no single choice for the parameters which describe cosmic ray behavior, which can account for all of the observed temporal and spatial variations, spectra, and electron vs, ion behavior. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. European Space Agcy, Estec, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Potchefstroom Univ Christian Higher Educ, ZA-2520 Potchefstroom, South Africa. CALTECH, Pasadena, CA 91125 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Univ Kiel, Inst Expt & Angew Phys, D-24118 Kiel, Germany. Univ Arizona, Tucson, AZ 85721 USA. PN Lebedev Phys Inst, Moscow 117924, Russia. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. NASA, Marshall Space Flight Ctr ES82, Huntsville, AL 35812 USA. New Mexico State Univ, Las Cruces, NM 88003 USA. Ctr Etud Saclay, CEA, DAPNIA, DSM,Serv Astrophys, F-91191 Gif Sur Yvette, France. Nagoya Univ, Solar Terr Environm Lab, Nagoya, Aichi, Japan. Univ New Hampshire, Ctr Space Sci, Durham, NH 03842 USA. RP Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RI Krainev, Mikhail/M-8509-2015 NR 80 TC 21 Z9 21 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JAN PY 1998 VL 83 IS 1-2 BP 179 EP 214 DI 10.1023/A:1005074923940 PG 36 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU056 UT WOS:000074156800017 ER PT J AU Klecker, B Mewaldt, RA Bieber, JW Cummings, AC Drury, L Giacalone, J Jokipii, JR Jones, FC Krainev, MB Lee, MA Le Roux, JA Marsden, RG McDonald, FB McKibben, RB Steenberg, CD Baring, MG Ellison, DC Lanzerotti, LJ Leske, RA Mazur, JE Moraal, H Oetliker, M Ptuskin, VS Selesnick, RS Trattner, KJ AF Klecker, B Mewaldt, RA Bieber, JW Cummings, AC Drury, L Giacalone, J Jokipii, JR Jones, FC Krainev, MB Lee, MA Le Roux, JA Marsden, RG McDonald, FB McKibben, RB Steenberg, CD Baring, MG Ellison, DC Lanzerotti, LJ Leske, RA Mazur, JE Moraal, H Oetliker, M Ptuskin, VS Selesnick, RS Trattner, KJ TI Anomalous cosmic rays - Report of working group 3 SO SPACE SCIENCE REVIEWS LA English DT Review ID DIFFUSIVE SHOCK ACCELERATION; SUCCESSIVE SOLAR MINIMA; PICKUP IONS; MAGNETOHYDRODYNAMIC TURBULENCE; TRANSPORT-EQUATION; DRIFT SOLUTIONS; ALFVEN WAVES; HELIOSPHERE; WIND; COMPONENT AB We review the observed properties of anomalous cosmic rays and the present status of our knowledge of the processes by which they originate. We compiled a comprehensive set of ACR energy spectral data from various spacecraft throughout the heliosphere during the passes of Ulysses over the poles of the Sun and present first results of a detailed modeling effort. In several contributions, we discuss the questions of injection and possible pre-acceleration of pickup ions, summarize new observations on the ionic charge composition, and present new results on the composition of minor ions in ACRs. C1 Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. CALTECH, Space Radiat Lab, Downs Lab MC 22047, Pasadena, CA 91125 USA. Univ Delaware, Newark, DE 19716 USA. Dublin Inst Adv Studies, Sch Cosm Phys, Dublin 4, Ireland. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. PN Lebedev Phys Inst, Moscow 117924, Russia. Univ New Hampshire, Durham, NH 03824 USA. Univ Maryland, College Pk, MD 20742 USA. European Space Agcy, Dept Space Sci, NL-2200 AG Noordwijk, Netherlands. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Potchefstroom Univ Christian Higher Educ, Dept Phys, Space Res Unit, ZA-2520 Potchefstroom, South Africa. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. AT&T Bell Labs, Murray Hill, NJ 07974 USA. IZMIRAN, Troitsk 142092, Moscow District, Russia. Aerosp Corp, Los Angeles, CA 90009 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. RI Krainev, Mikhail/M-8509-2015; Drury, Luke/B-1916-2017 OI Drury, Luke/0000-0002-9257-2270 NR 71 TC 27 Z9 27 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD JAN PY 1998 VL 83 IS 1-2 BP 259 EP 308 DI 10.1023/A:1005031108919 PG 50 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ZU056 UT WOS:000074156800019 ER PT S AU Millis, MG AF Millis, MG BE ElGenk, MS TI Breakthrough propulsion physics workshop preliminary results SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB In August, 1997, a NASA workshop was held to assess the prospects emerging from physics that might lead to creating the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, attaining the maximum transit speeds physically possible, and breakthrough methods of energy production to power such devices. Because these propulsion goals are presumably far from fruition, a special emphasis was to identify affordable, near-term, and credible research that could make measurable progress toward these propulsion goals. Experiments and theories were discussed regarding the coupling of gravity and electromagnetism, vacuum fluctuation energy, warp drives and wormholes, and superluminal quantum tunneling. Preliminary results of this workshop are presented, along with the status of the Breakthrough Propulsion Physics program that conducted this workshop. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Millis, MG (reprint author), NASA, Lewis Res Ctr, 21000 Brookpark Rd,MS 60-4, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 3 EP 12 PG 10 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200001 ER PT S AU Millar, PS Sirota, JM AF Millar, PS Sirota, JM BE ElGenk, MS TI Geoscience laser altimeter system - Stellar reference system SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB GLAS is an EOS space-based laser altimeter being developed to profile the height of the Earth's ice sheets with similar to 15 cm single shot accuracy from space under NASA's Mission to Planet Earth (MTPE). The primary science goal of GLAS is to determine if the ice sheets are increasing or diminishing for climate change modeling. This is achieved by measuring the ice sheet heights over Greenland and Antarctica to 1.5 cm/yr over 100 km x 100 km areas by crossover analysis (Zwally 1994). This measurement performance requires the instrument to determine the pointing of the laser beam to similar to 5 urad (1 arcsecond), 1-sigma, with respect to the inertial reference frame. The GLAS design incorporates a stellar reference system (SRS) to relate the laser beam pointing angle to the star field with this accuracy. This is the first time a spaceborne laser altimeter is measuring pointing to such high accuracy. The design for the stellar reference system combines an attitude determination system (ADS) with a laser reference system (LRS) to meet this requirement. The SRS approach and expected performance are described in this paper. C1 NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. RP Millar, PS (reprint author), NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Code 924, Greenbelt, MD 20771 USA. RI Millar, Pamela/B-4426-2013 NR 0 TC 0 Z9 0 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 27 EP 32 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200004 ER PT S AU Abshire, JB Smith, JC Schutz, BE AF Abshire, JB Smith, JC Schutz, BE BE ElGenk, MS TI The geoscience laser altimeter system (GLAS) SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB GLAS is a space-based lidar designed for NASA's Mission to Planet Earth (MTPE) Laser Altimeter Mission (LAM). The GLAS instrument will precisely measure the heights of the polar ice sheets, to profile areas of the Earth's land topography, and to profile the structure of clouds and aerosols on a global scale. The LAM mission utilizes a small dedicated spacecraft in a polar orbit at 598 km altitude with an inclination of 94 degrees. GLAS is being developed to launch in 2001 and to operate continuously for a minimum of 3 years with a goal of 5 years. C1 NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD 20771 USA. RP Abshire, JB (reprint author), NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Code 924, Greenbelt, MD 20771 USA. RI Abshire, James/I-2800-2013 NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 33 EP 37 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200005 ER PT S AU Huang, ZC Mott, DB Shu, PK AF Huang, ZC Mott, DB Shu, PK BE ElGenk, MS TI 256x256 GaN ultraviolet imaging array SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB We have successfully developed a 256x256 photoconductive GaN area imaging array using a metal-semiconductor-metal structure. The array, with its pixels (30 mu m(2)) indium bump bonded to a readout integrated circuit, showed a 90% of yield. The spectral response of the array is consistent with the measured spectral response of the single photoconductors fabricated elsewhere on the source wafer. C1 NASA, Goddard Space Flight Ctr, Solid State Device Dev Branch, Greenbelt, MD 20771 USA. RP Huang, ZC (reprint author), NASA, Goddard Space Flight Ctr, Solid State Device Dev Branch, Code 718-1, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 39 EP 43 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200006 ER PT S AU Martineau, RJ Peters, F Burgess, A Kotecki, C Manthripragada, S Godfrey, J Krebs, D Mott, D Shu, P Shi, JZ Hu, K AF Martineau, RJ Peters, F Burgess, A Kotecki, C Manthripragada, S Godfrey, J Krebs, D Mott, D Shu, P Shi, JZ Hu, K BE ElGenk, MS TI Split-geometry detectors, our eyes in space SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Infrared detectors have projected our ability to explore our planet and our solar system far beyond the spatial, temporal, and spectral limitations of our natural vision. As such, they are our eyes in space, constantly searching the heavens, and sending back information about the origin, constitution, and dynamics of planetary atmospheres, and other processes of interest. Their ability to do this effectively depends on their sensitivity. Today, long wave PC (photoconductive) HgCdTe detectors are the detectors of choice for applications requiring high sensitivity at long wavelengths and elevated temperature. However, planetary exploration and space surveillance of the earth's climatic condition are presently still limited by the sensitivity of available detectors. This paper will describe detectors developed at Goddard to provide enhanced performance for applications such as the CIRS/Cassini mission to Saturn and Titan, and the GOES weather satellite. Specifically, this paper will show theoretically and experimentally how detectors of split-geometry design can be exploited to increase detector resistance, responsivity, and detectivity, while decreasing 1/f noise and power dissipation. Photomicrographs of split-geometry detectors will be shown, and data demonstrating theoretical split-geometry design advantages will be presented for flight arrays built for the CIRS/Cassini mission, and for advanced detectors for GOES. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Martineau, RJ (reprint author), NASA, Goddard Space Flight Ctr, Code 718, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 45 EP 54 PG 10 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200007 ER PT S AU Stahle, C Shi, J Shu, P Barthelmy, S Parsons, A Snodgrass, S AF Stahle, C Shi, J Shu, P Barthelmy, S Parsons, A Snodgrass, S BE ElGenk, MS TI Cdznte technology for gamma ray detectors SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB CdZnTe detector technology has been developed at NASA Goddard for imaging and spectroscopy applications in hard x-ray and gamma ray astronomy. A CdZnTe strip detector array with capabilities for are second imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. CdZnTe detectors also have applications for medical imaging, environmental protection, transportation safety, nuclear safeguards and safety, nuclear non-proliferation, and national security. This can be accomplished from space and also from portable detectors on earth. One of the great advantages of CdZnTe is that the detectors can be operated at room temperature which eliminates the need for cryogenic cooling. CdZnTe detectors have good energy resolution (3.6 keV at 60 keV) and excellent spatial resolution (< 100 microns). NASA Goddard has developed the fabrication technology to make a variety of planar, strip, and pixel detectors and integrated these detectors to high density electronics. We have built a 2 x 2 and a large area (60 cm(2), 36 detectors) 6 x 6 strip detector array. This paper will summarize the CdZnTe detector fabrication and packaging technology developed at Goddard. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stahle, C (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012; Parsons, Ann/I-6604-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 55 EP 60 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200008 ER PT S AU Ewin, A Fortin, M Shu, P Das, NC Aslam, S Smith, W McAdoo, J AF Ewin, A Fortin, M Shu, P Das, NC Aslam, S Smith, W McAdoo, J BE ElGenk, MS TI Large aspect ratio detector array for space applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB At the Goddard Space Flight Center (GSFC) Detector Development Laboratory (DDL), we have custom designed and fabricated a chip which consists of an interleaved linear array of 1 x 512 pinned photo-diode (PD) sensing pixels, which have dimensions 200 mu m x 6 mu m, together with a parallel detector register and a serial readout register. The registers use a triple polysilicon CCD design. This paper presents some aspects of the design, processing and operating techniques used for optimizing the full well capacity of the odd shaped photo-diodes, efficiency of photodiode to CCD transfer and the charge handling capability of the various CCD/output structures. By using a pinning implant in the PD area together with a larger transfer gate voltage the desired photo-diode signal level of 5 Me- was achieved. C1 NASA, Goddard Space Flight Ctr, Solid State Device, Greenbelt, MD 20771 USA. RP Ewin, A (reprint author), NASA, Goddard Space Flight Ctr, Solid State Device, Greenbelt, MD 20771 USA. RI Aslam, Shahid/D-1099-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 61 EP 65 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200009 ER PT S AU Wood, HJ Jenstrom, D Wilson, M Hinkal, S Kirchman, F AF Wood, HJ Jenstrom, D Wilson, M Hinkal, S Kirchman, F BE ElGenk, MS TI Wide-field high-performance geosynchronous imaging SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Meeting Abstract CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wood, HJ (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 551, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 76 EP 76 PG 1 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200011 ER PT S AU Forouhar, S Young, MG Keo, S Davis, L Muller, R Maker, P AF Forouhar, S Young, MG Keo, S Davis, L Muller, R Maker, P BE ElGenk, MS TI Semiconductor lasers for NASA applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Lasers play a key role in a wide variety of applications relevant to NASA missions and instruments. These include such diverse areas as spectroscopy, communications, signal processing, metrology and micro-instruments. The unique characteristics of lasers including high optical power in a narrow wavelength range, small beam divergence, phase coherence, and high-frequency modulation, make lasers ideal sources for many of these applications. However, the large size, high power requirements, and relative fragility of conventional gas and solid-state lasers have limited their usefulness for many spaceborne instruments. With the advent of semiconductor lasers, it is now possible to fabricate much smaller, higher efficiency lasers and laser instruments, making them practical choices for a wide variety of applications in space missions. Semiconductor lasers also offer orders-of-magnitude increases in communication bandwidth which enables tremendous enhancements in spacecraft to ground and inter-instrument data transmission rates. Further reduction in power and weight can be gained through the monolithic integration of lasers with other optical and electrical components. Integrated architectures also offer advantages in robustness and system simplicity. The implementation of semiconductor lasers and integrated optics can impact a wide variety of systems capabilities. The following describes few applications of semiconductor lasers that are of significant interest to NASA. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Forouhar, S (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 INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 85 EP 90 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200014 ER PT S AU Barnes, JC AF Barnes, JC BE ElGenk, MS TI Solid state laser technology and atmospheric sensing applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Future NASA space missions to enable global monitoring of the earth's atmosphere will include measurements of ozone, water vapor, aerosols and clouds as well as global wind velocity. These important elements and parameters effect climate change, atmospheric chemistry and dynamics, atmospheric transport and, in general, the health of the planet. NASA (D) under bar ifferential (A) under bar bsorption (L) under bar idar (DIAL) and backscatter lidar techniques are leading candidates for active remote sensing of molecular constituents and atmospheric phenomena from advanced high-altitude aircraft and space platforms. DIAL and lidar systems operating from space have the capability to completely map the earth's atmosphere for these and other molecules as well as for tracking atmospheric phenomena such as winds and volcanic dust transport. This paper provides an overview of NASA Langley's development of advanced solid state lasers, harmonic generators, and wave mixing techniques aimed at providing the broad range of wavelengths necessary to meet measurement goals of NASA's Mission To Planet Earth (MTPE) Enterprise and potentially for applications in the Space Science Enterprise. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Barnes, JC (reprint author), NASA, Langley Res Ctr, Mail Stop 474, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 95 EP 100 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200016 ER PT S AU Gentry, BM AF Gentry, BM BE ElGenk, MS TI Enabling technologies for a global tropospheric wind lidar system SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Remote measurement of tropospheric winds is recognized as one of the most important measurements for the atmospheric sciences. Winds can be measured as a function of altitude from satellites using lidar (LIght Detection And Ranging) systems which sense the Doppler shifted frequency of the laser signal backscattered from the atmosphere. NASA has had a long term commitment to developing the technologies required to enable global wind sensing. This paper describes recent developments in the Doppler lidar key technology areas. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Gentry, BM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 101 EP 105 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200017 ER PT S AU Afzal, RS AF Afzal, RS BE ElGenk, MS TI Diode-pumped solid state lasers for space-based applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB NASA is embarking on a new era of laser remote sensing instruments from space. This paper focus' specifically on the laser technology involved in two present NASA missions. The first is a current mission, the Mars Orbiter Laser Altimeter and the second is the Geoscience Laser Altimeter System scheduled to launch in 2001. The laser transmitters in these space-based remote sensing instruments are discussed in the context of requirements of these two missions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Afzal, RS (reprint author), NASA, Goddard Space Flight Ctr, Code 924, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 107 EP 111 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200018 ER PT S AU Folta, DC Quinn, DA AF Folta, DC Quinn, DA BE ElGenk, MS TI An algorithm for enhanced formation flying of satellites in low earth orbit SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB With scientific objectives for Earth observation programs becoming more ambitious and spacecraft becoming more autonomous, the need for innovative technical approaches on the feasibility of achieving and maintaining formations of spacecraft has come to the forefront. The trend to develop small low-cost spacecraft has led many scientists to recognize the advantage of flying several spacecraft in formation to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single large platform. Yet, formation flying imposes additional complications on orbit maintenance, especially when each spacecraft has its own orbit requirements. However, advances in automation and technology proposed by the Goddard Space Flight Center (GSFC) allow more of the burden in maneuver planning and execution to be placed onboard the spacecraft, mitigating some of the associated operational concerns. The purpose of this paper is to present GSFC's Guidance, Navigation, and Control Center's (GNCC) algorithm for Formation Flying of the low earth orbiting spacecraft that is part of the New Millennium Program (NMP). This system will be implemented as a close-loop flight code onboard the NMP Earth Orbiter-1 (EO-1) spacecraft. Results of this development can be used to determine the appropriateness of formation flying for a particular case as well as operational impacts. Simulation results using this algorithm integrated in an autonomous 'fuzzy logic' control system called AutoCon (TM) are presented. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Folta, DC (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 119 EP 126 PG 8 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200020 ER PT S AU Croft, J Deily, J Hartman, K Weidow, D AF Croft, J Deily, J Hartman, K Weidow, D BE ElGenk, MS TI Technology initiatives for the autonomous guidance, navigation, and control of single and multiple satellites SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB In the twenty-first century, NASA envisions frequent low-cost missions to explore the solar system, observe the universe, and study our planet. To realize NASA's goal, the Guidance, Navigation, and Control Center (GNCC) at the Goddard Space Flight Center sponsors technology programs that enhance spacecraft performance, streamline processes and ultimately enable cheaper science. Our technology programs encompass control system architectures, sensor and actuator components, electronic systems, design and development of algorithms, embedded systems and space vehicle autonomy. Through collaboration with government, universities, non-profit organizations, and industry, the GNCC incrementally develops key technologies that conquer NASA's challenges. This paper presents an overview of several innovative technology initiatives for the autonomous guidance, navigation, and control (GN&C) of satellites. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Croft, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 141 EP 146 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200023 ER PT S AU Bilbro, JW AF Bilbro, JW BE ElGenk, MS TI Advanced lightweight optics development for space applications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB A considerable amount of effort over the past year has been devoted to exploring ultra-lightweight optics for two specific NASA programs, the Next Generation Space Telescope (NGST), and the High Throughput X-ray Spectrometer (HTXS). Experimental investigations have been undertaken in a variety of materials including glass, composites, nickel, beryllium, Carbon fiber reinforced Silicon Carbide (CSiC), Reaction Bonded Silicon Carbide, Chemical Vapor Deposited Silicon Carbide, and Silicon. Overall results of these investigations will be summarized, and specific details will be provided concerning the in-house development of ultra-lightweight nickel replication for both grazing incidence and normal incidence optics. This will include x-ray test results of the grazing incidence optic and cryogenic test results of the normal incidence optic. The status of two 1.5 meter diameter demonstration mirrors for NGST will also be presented. These two demonstrations are aimed at establishing the capability to manufacture and test mirrors that have an areal density of 15 kilograms per square meter. Efforts in thin membrane mirrors and Fresnel lenses will also be briefly discussed. C1 NASA, Opt & Radio Frequency Div, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Bilbro, JW (reprint author), NASA, Opt & Radio Frequency Div, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 185 EP 187 PG 3 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200030 ER PT S AU Lake, MS Peterson, LD Hachkowski, MR Hinkle, JD Hardaway, LR AF Lake, MS Peterson, LD Hachkowski, MR Hinkle, JD Hardaway, LR BE ElGenk, MS TI Research on the problem of high-precision deployment for large-aperture space-based science instruments SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The present paper summarizes results from an ongoing research program conducted jointly by the University of Colorado and NASA Langley Research Center since 1994. This program has resulted in general guidelines for the design of high-precision deployment mechanisms, and tests of prototype deployable structures incorporating these mechanisms have shown microdynamically stable behavior (i.e., dimensional stability to parts per million). These advancements have resulted from the identification of numerous heretofore unknown microdynamic and micromechanical response phenomena, and the development of new test techniques and instrumentation systems to interrogate these phenomena, In addition, recent tests have begun to interrogate nanomechanical response of materials and joints and have been used to develop an understanding of nonlinear nanodynamic behavior in microdynamically stable structures, The ultimate goal of these efforts is to enable nano-precision active control of micro-precision deployable structures (i.e., active control to a resolution of parts per billion). C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Lake, MS (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 188 EP 198 PG 11 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200031 ER PT S AU Hoder, DJ Zernic, MJ Mallasch, PG Bhasin, K Brooks, DE Beering, DR AF Hoder, DJ Zernic, MJ Mallasch, PG Bhasin, K Brooks, DE Beering, DR BE ElGenk, MS TI Telepresence by high-data rate satellite communications SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Telepresence allows a person to experience as if he or she is actually present in a different place or time. For remotely located sites, satellite communications are being utilized to develop the medium of telepresence. In this presentation we summarize several experiments conducted using NASA's Advanced Communications Technology Satellite (ACTS) and fiber-optic networks to demonstrate telepresence utilizing data rates ranging from 155 to 622 megabytes per second. In addition, we identify future challenges and directions for telepresence applications over advanced high data-rate hybrid (satellite and terrestrial) networks. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Hoder, DJ (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 235 EP 235 PG 1 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200037 ER PT S AU Agan, M Voisinet, L Devereaux, A AF Agan, M Voisinet, L Devereaux, A BE ElGenk, MS TI NASA's Wireless Augmented Reality Prototype (WARP) SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The objective of Wireless Augmented Reality Prototype (WARP) effort is to develop and integrate advanced technologies for real-time personal display of information relevant to the health and safety of space station/shuttle personnel. The WARP effort will develop and demonstrate technologies that will ultimately be incorporated into operational Space Station systems and that have potential earth applications such as aircraft pilot alertness monitoring and in various medical and consumer environments where augmented reality is required. To this end a two phase effort will be undertaken to rapidly develop a prototype (Phase I) and an advanced prototype (Phase II) to demonstrate the following key technology features that could be applied to astronaut internal vehicle activity (IVA) and potentially external vehicle activity (EVA) as well: 1) mobile visualization, and 2) distributed information system access. Specifically, Phase I will integrate a low power, miniature wireless communication link and a commercial biosensor with a head mounted display. The Phase I design will emphasize the development of a relatively small, lightweight, and unobtrusive body worn prototype system. Phase II will put increased effort on miniaturization, power consumption reduction, increased throughput, higher resolution, and "wire removal" of the subsystems developed in Phase I. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Agan, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 236 EP 241 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200038 ER PT S AU Lesh, J Wilson, K Sandusky, J Jeganathan, M Hemmati, H Monacos, S Page, N Biswas, A AF Lesh, J Wilson, K Sandusky, J Jeganathan, M Hemmati, H Monacos, S Page, N Biswas, A BE ElGenk, MS TI High-rate optical communications links for virtual presence in space SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB As man continues the exploration of space, either from platforms in Earth-orbit or from missions to the bodies of our solar system, there will be an on-going need to keep the public engaged in the process so that the general populace can share in the excitement of discovery and the inquisitive (professional or student) can participate in the data mining. To do this will require the development of high-data-rate communications links for data return and dissemination. However, the cost constraints on future missions will require that these high-rate links be smaller and lighter-weight than even the lower-capacity systems that have been used in the past. NASA has been developing free-space optical communications technology for just such missions. This paper will discuss the technology developments and system demonstrations that have been accomplished to date, and will describe preparations for the space demonstrations that will validate the performance of this new technology. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lesh, J (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 AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 243 EP 248 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200039 ER PT S AU Chato, DJ Van Dyke, M Batty, JC Schick, S AF Chato, DJ Van Dyke, M Batty, JC Schick, S BE ElGenk, MS TI Status and design concepts for the Hydrogen On-Orbit Storage And Supply Experiment SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB This paper studies concepts for the Hydrogen On-Orbit Storage And Supply Experiment (HOSS). HOSS is a space flight experiment whose objectives are: Show stable gas supply for storage and direct gain solar-thermal thruster designs; and evaluate and compare low-g performance of active and passive pressure control via a thermodynamic vent system (TVS) suitable for solar-thermal upper stages. This paper shows that the necessary experimental equipment for HOSS can be accommodated in a small hydrogen dewar of 36 to 80 liter. Thermal designs for these dewars which meet the on-orbit storage requirements can be achieved. Furthermore ground hold insulation and shielding concepts are achieved which enable storing initially subcooled liquid hydrogen in these small dewars without venting in excess of 144 hours. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Chato, DJ (reprint author), NASA, Lewis Res Ctr, Mail Stop 60-4,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 276 EP 281 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200045 ER PT S AU Peterson, T Pencil, E Arrington, L Hoskins, WA Meckel, NJ LeDuc, JR Bromaghim, DR Malak, J Blandino, JJ Moore, B AF Peterson, T Pencil, E Arrington, L Hoskins, WA Meckel, NJ LeDuc, JR Bromaghim, DR Malak, J Blandino, JJ Moore, B BE ElGenk, MS TI Development of an advanced Pulsed Plasma Thruster (PPT) and Plume Diagnostic Experiment (PDE) for demonstration on the MightySat II.1 spacecraft SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The Pulsed Plasma Thruster (PPT) Space Demonstration Program will characterize the performance of an experimental PPT as an orbit raising propulsion system with a 25% reduction in dry mass and twice the power of the LES 8/9 PPT. The project is a partnership of the USAF Phillips Laboratory and NASA Lewis Research Center. The PPT is manifested on the MightySat II.1 satellite scheduled for launch in January, 2000. An extensive breadboard PPT testing program is underway and data from those tests will be used to finalize the design of the flight version PPT. A plume diagnostic experiment (PDE) will be used to characterize contamination rates and effects on surface thermo-optical properties due to PPT plume contamination. These experiments will then undergo full space qualification testing prior to integration with the MightySat II.1 spacecraft. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Peterson, T (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 295 EP 301 PG 7 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200048 ER PT S AU Hastings, LJ Martin, JJ AF Hastings, LJ Martin, JJ BE ElGenk, MS TI Experimental testing of a foam/multilayer insulation (FMLI) thermal control system (TCS) for use on a cryogenic upper stage SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB An 18-m(3) system-level test bed termed the Multipurpose Hydrogen Test Bed (MHTB has been used to evaluate a foam/multilayer combination insulation concept. The foam element (Isofoam SS-1171) protects against ground hold/ascent flight environments, and allows the use of dry nitrogen purge as opposed to a more complex/heavy helium purge subsystem. The MLI (45 layers of Double Aluminized Mylar with Dacron spacers) is designed for an on-orbit storage period of 45 days. Unique MLI features included; a variable layer density (reduces weight and radiation losses), larger but fewer DAM vent perforations (reduces radiation losses), and a roll wrap installation which resulted in a very robust MLI and reduced both assembly man-hours and seam heat leak. Ground hold testing resulted in an average heat leak of 63 W/m(2) and purge gas liquefaction was successfully prevented. The orbit hold simulation produced a heat leak of 0.22 W/m(2) with 305 K boundary which, compared to historical data, represents a 50-percent heat leak reduction. C1 NASA, Propuls Lab EP63, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Hastings, LJ (reprint author), NASA, Propuls Lab EP63, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 1 Z9 1 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 331 EP 341 PG 11 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200054 ER PT S AU Johnson, L Ballance, J AF Johnson, L Ballance, J BE ElGenk, MS TI Propulsive small expendable deployer system (ProSEDS) space demonstration SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system, The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changing-all using electrodynamic thrust, ProSEDS, which is planned to fly in 2000, will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a tether (5-km bare wire; plus 15-km spectra) from a Delta II upper stage to achieve similar to 0.4N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. ProSEDS will utilize tether-generated current to provide limited spacecraft power, in addition to the use of this technology to provide orbit transfer of payloads and upper stages from low-Earth orbit (LEO) to higher orbits, it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere. C1 NASA, Program Dev PS02, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Johnson, L (reprint author), NASA, Program Dev PS02, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 354 EP 358 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200057 ER PT S AU Curreri, PA Kaukler, WF Sen, S AF Curreri, PA Kaukler, WF Sen, S BE ElGenk, MS TI Real-time X-ray transmission microscopy for fundamental studies solidification: Al-Al2Au eutectic SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB High resolution real-time X-ray Transmission Microscopy, XTM, has been applied to obtain information fundamental to solidification of optically opaque metallic systems. We have previously reported the measurement of the solute profile in the liquid, phase growth, and detailed solid-liquid interfacial morphology of aluminum based alloys with exposure times less than 2 seconds. Recent advances in XTM furnace design have provided an increase in real-time magnification (during solidification) for the XTM from 40X to 160X. The increased magnification has enabled for the first time the XTM imaging of real-time growth of fibers and particles with diameters of 5 mu m. We have previously applied this system to study the kinetics of formation and morphological evolution of secondary fibers and particles in AI-Bi monotectic alloys. In this paper we present the preliminary results of the first real-time observations of fiber morphology evolution in optically opaque bulk metal sample of Aluminum-Gold eutectic alloy. These studies show that the XTM can be applied to study the fundamentals of eutectic and monotectic solidification. We are currently attempting to apply this technology in the fundamentals of solidification in microgravity. C1 NASA, Space Sci Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Curreri, PA (reprint author), NASA, Space Sci Lab, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 389 EP 396 PG 8 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200063 ER PT S AU Rhim, WK AF Rhim, WK BE ElGenk, MS TI High temperature electrostatic sample levitator as a future containerless materials processing facility in space SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Meeting Abstract CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 397 EP 398 PG 2 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200064 ER PT S AU Weislogel, MM Hsieh, KC AF Weislogel, MM Hsieh, KC BE ElGenk, MS TI Stability of a capillary surface in a rectangular container SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The linearized governing equations for an ideal fluid are solved numerically for the stability of free capillary surfaces in rectangular containers against, unfavorable disturbances (accelerations, i.e. Rayleigh-Taylor instability). The preliminary results are expressed graphically in terms of a critical Bond number as a function of system contact angle. A critical wetting phenomena in the corners is shown to significantly alter the region of stability for such containers when contrast to simpler geometries such as the circular cylinder or the infinite rectangular slot. Such computational results provide additional constraints for the design of fluids systems for space-based applications. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Weislogel, MM (reprint author), NASA, Lewis Res Ctr, MS 500-102, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 404 EP 412 PG 9 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200066 ER PT S AU Weislogel, MM McQuillen, JB AF Weislogel, MM McQuillen, JB BE ElGenk, MS TI Hydrodynamic dryout in two-phase flows: Observations of low bond number systems SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Dryout occurs readily in certain slug and annular two-phase flows for systems that exhibit partial wetting. The mechanism for the ultimate rupture of the film is attributed to van der Waals forces, but the pace towards rupture is quickened by the surface tension instability (Rayleigh-type) of the annular film left by the advancing slug and by the many perturbations of the free surface present in the Re-g similar to O(10(3)), Re-l similar to O(10(4)), and Ca similar to O(10(-1)) hows. Results from low-gravity experiments using three different test fluids are presented and discussed. For the range of tests conducted, the effect of increasing viscosity is shown to eliminate the film rupture while the decrease of surface tension via a surfactant additive is shown to dramatically enhance it. Laboratory measurements using capillary tubes are presented which reveal the sensitivity of the dryout phenomena to particulate and surfactant contamination. From such observations, dryout due to the hydrodynamic-van der Waals instability can be expected in a certain range of flow parameters in the absence of heat transfer. The addition of heat transfer may only exacerbate the problem by producing thermal transport lines replete with "hot spots." A caution to this effect is issued to future space systems designers concerning the use of partially wetting working fluids. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Weislogel, MM (reprint author), NASA, Lewis Res Ctr, MS 500-102, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 413 EP 421 PG 9 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200067 ER PT S AU Balasubramaniam, R AF Balasubramaniam, R BE ElGenk, MS TI Thermocapillary flow near a corner in a thin liquid layer SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The thermocapillary flow in a thin liquid layer present in a differentially heated cavity is analyzed in the limit of creeping flow. Away from the end walls, it is shown that the flow field is parallel. The turning of the flow is accomplished in regions near the end walls. The method of matched asymptotic expansions is used to analyze the flow fields in these regions. An analytic solution has been obtained to the inner equations using the method of biorthogonal series expansions. The coefficients in the infinite series expansion for the streamfunction have been determined numerically after truncation of the series. C1 NASA, Natl Ctr Micrograv Res Fluids & Combust, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Balasubramaniam, R (reprint author), NASA, Natl Ctr Micrograv Res Fluids & Combust, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 429 EP 434 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200069 ER PT S AU Allen, JS Hallinan, K Lekan, J AF Allen, JS Hallinan, K Lekan, J BE ElGenk, MS TI A study of the fundamental operations of a capillary driven heat transfer device in both normal and low gravity - Part 1. Liquid slug formation in low gravity SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Research has been conducted to observe the operation of a capillary pumped loop (CPL) in both normal and low gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped heat transport devices in low gravity; specifically; evaporator dryout, are not understood and the available data for analyzing the failures is incomplete. To observe failure in these devices an idealized experimental CPL was configured for testing in both a normal-gravity and a low-gravity environment. The experimental test loop was constructed completely of Pyrex tubing to allow for visualization of system operations. Heat was added to the liquid on the evaporator side of the loop using resistance heaters and removed on the condenser side via forced convection of ambient air. A video camera was used to record the behavior of both the condenser and the evaporator menisci simultaneously. Low-gravity experiments were performed during the Microgravity Science Laboratory (MSL-1) mission performed onboard the Space Shuttle Columbia in July of 1997. During the MSL-1 mission, a failure mechanism, heretofore unreported, was observed. In every experiment performed a slug of liquid would form at the transition from a bend to a straight run in the vapor line. Ultimately, this liquid slug prevents the flow of vapor to the condenser causing the condenser to eventually dryout. After condenser dryout, liquid is no longer fed into the evaporator and it, too, will dry out resulting in device failure. An analysis is presented to illustrate the inevitable formation of such liquid slugs in CPL devices in low gravity. C1 Univ Dayton, NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Allen, JS (reprint author), Univ Dayton, NASA, Lewis Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 471 EP 477 PG 7 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200076 ER PT S AU Smitherman, DV AF Smitherman, DV BE ElGenk, MS TI Space transfer services as a precursor to space business parks SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Boeing Defense and Space Group and NASA, Marshall Space Flight Center conducted a study in 1996-1997 on the topic of commercial space business parks under the sponsorship of the former Office of Advanced Concepts at NASA Headquarters (Marshall 1997). The findings of this 7-month study are used to present possible strategies for near-term commercial developments in space. Related data from NASA studies on public space travel, and commercial space transportation are included along with the author's observations. It is hoped that this analysis will assist future entrepreneurs in the development of commercial space business parks, in conclusion, it appears that a market could soon become viable for commercial space transfer services, and that this market could form the infrastructure to grow the first commercial space business park. C1 NASA, George C Marshall Space Flight Ctr, Program Plans & Requirements Off, Huntsville, AL 35812 USA. RP Smitherman, DV (reprint author), NASA, George C Marshall Space Flight Ctr, Program Plans & Requirements Off, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 538 EP 543 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200088 ER PT S AU Peterson, L Samson, J Conrad, D Clark, K AF Peterson, L Samson, J Conrad, D Clark, K BE ElGenk, MS TI Advanced imaging microscope tools applied to microgravity research investigations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Meeting Abstract CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies C1 NASA, Ctr Micrograv Automat Technol, ERIM, Ann Arbor, MI 48113 USA. RP Peterson, L (reprint author), NASA, Ctr Micrograv Automat Technol, ERIM, POB 134001, Ann Arbor, MI 48113 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 647 EP 647 PG 1 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200106 ER PT S AU Ross, MD Smith, J Montgomery, K Cheng, R Linton, S AF Ross, MD Smith, J Montgomery, K Cheng, R Linton, S BE ElGenk, MS TI Fundamental gravitational research and emerging technologies: The connection SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Life Sciences basic research, particularly in the unique area of neuronal plasticity, would seem to be an unlikely source of computer-based technologies. Nevertheless, basic research into the neuronal plasticity of sites of communication (synapses) between gravity-sensing cells and neurons carrying messages to the brain has resulted in technologies of interest to the scientific and medical communities. it has also led to the establishment of a National Institute for Biocomputation that will be a partnership between federal, academic and industrial partners to provide cutting edge resources for the work. This report describes the current state of the art of the technologies developed in the Biocomputation Center, and the objectives of the new National institute in the realm of technology facilitation and transfer. C1 NASA, Ames Res Ctr, Biocomp Ctr, Moffett Field, CA 94035 USA. RP Ross, MD (reprint author), NASA, Ames Res Ctr, Biocomp Ctr, Mail Stop 239-11, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 822 EP 828 PG 7 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200136 ER PT S AU Doarn, CR Whitten, R AF Doarn, CR Whitten, R BE ElGenk, MS TI NASA's telemedicine testbeds: Commercial benefit SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The National Aeronautics and Space Administration (NASA) has been developing and applying telemedicine to support space flight since the Agency's beginning. Telemetry of physiological parameters from spacecraft to ground controllers is critical to assess the health status of humans in extreme and remote environments. Requisite systems to support medical care and maintain readiness will evolve as mission duration and complexity increase. Developing appropriate protocols and procedures to support multinational, multicultural missions is a key objective of this activity. NASA has created an Agency-wide strategic plan that focuses on the development and integration of technology into the health care delivery systems for space flight to meet these challenges. In order to evaluate technology and systems that can enhance inflight medical care and medical education, NASA has established and conducted several testbeds. Additionally, in June of 1997, NASA established a Commercial Space Center (CSC) for Medical Informatics and Technology Applications at Yale University School of Medicine. These testbeds and the CSC foster the leveraging of technology and resources between government, academia and industry to enhance health care. This commercial endeavor will influence both the delivery of health care in space and on the ground. To date, NASA's activities in telemedicine have provided new ideas in the application of telecommunications and information systems to health care. NASA's Spacebridge to Russia, an Internet-based telemedicine testbed, is one example of how telemedicine and medical education can be conducted using the Internet and its associated tools. Other NASA activities, including the development of a portable telemedicine workstation, which has been demonstrated on the Crow Indian Reservation and in the Texas Prison System, show promise in serving as significant adjuncts to the delivery of health care. As NASA continues to meet the challenges of space flight, the technologies adapted to support humans in extreme and remote environments, and the resultant protocols and procedures will further evolve the commercial practice of medicine and thereby enhance life on Earth. C1 NASA, Aerosp Med Div, Washington, DC 20546 USA. RP Doarn, CR (reprint author), NASA, Aerosp Med Div, 300 E St SW, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 829 EP 834 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200137 ER PT S AU Flynn, M Bubenheim, D AF Flynn, M Bubenheim, D BE ElGenk, MS TI Commercialization of regenerative life support systems SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Over the past 30 years NASA has funded research into the development of self sustained habitats for use as future Lunar and Martian outposts. A key element of this work has been the development of small scale liquid and solid waste processors. A secondary goal of this research has been to transfer this technology base to the private sector. This paper describes several programs which are involved in this Advanced Life Support technology transfer activity. The two programs highlighted in this paper are the CELSS Antarctic Analog Program and the Advanced Life Support for Extreme Environments program. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Flynn, M (reprint author), NASA, Ames Res Ctr, MS 239-15, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 835 EP 839 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200138 ER PT S AU Tucker, DS Workman, GL Smith, GA AF Tucker, DS Workman, GL Smith, GA BE ElGenk, MS TI Commercial production of heavy metal fluoride glass fiber in space SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB International Space Station Alpha (ISSA) will provide a platform not only for materials research but also a possible means to produce products in space which cannot be easily produced on the ground. Some products may even be superior to those now produced in unit gravity due to the lack of gravity induced convection effects. Our research with ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN glass) has shown that gravity does indeed play a major role in the crystallization behavior of this material. At the present time ZBLAN is being produced on earth in fiber optic form for use in surgical lasers and fiber optic lasers among other applications. High attenuation coefficients, however, have kept this material from being used in other applications such as long haul data transmission links. The high attenuation coefficients are due to impurities which can be removed through improved processing techniques and crystals which can only be removed or prevented from forming by processing in a reduced gravity environment. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Tucker, DS (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Mail Stop ES75, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 847 EP 851 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200140 ER PT S AU Schuiling, RL O'Connor, EA AF Schuiling, RL O'Connor, EA BE ElGenk, MS TI Development of a quick-reaction commercial launch site at the Cape Canaveral air station SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB This paper provides a description of a project which will provide a launch complex for several launch vehicles and sounding rockets. A design requirement for the complex is that it be a quick-reaction facility capable of supporting a launch within as short as six hours from notification of the need to launch. The paper describes the organization of a state and federal effort to accomplish this so as to enhance the capability of the Cape Canaveral launch site to support commercial space launch activity. The study effort envisions commercial launches as the driving need, however scientific launches will also benefit from this capability and they are also addressed. Quick-reaction missions in the fields of space commerce - termed "Business Express" - and in the fields of science - termed "Science Express" - are identified. The Spaceport Florida Authority is undertaking the development of this launch capability. The Spaceport Florida Authority together with its past programs as well as future efforts is described, as is the proposed quick-reaction launch complex. C1 NASA, Kennedy Space Ctr, Liaison Off, Spaceport Florida Author, Cocoa Beach, FL 32931 USA. RP Schuiling, RL (reprint author), NASA, Kennedy Space Ctr, Liaison Off, Spaceport Florida Author, 150 Cocoa Isles Blvd, Cocoa Beach, FL 32931 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 899 EP 903 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200149 ER PT S AU Rhodes, RE Byrd, RJ AF Rhodes, RE Byrd, RJ BE ElGenk, MS TI A novel methodology for estimating upper limits of major cost drivers for profitable conceptual launch system architectures SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB This paper presents a "back of the envelope" technique for fast, timely, on-the-spot, assessment of affordability (profitability) of commercial space transportation architectural concepts. The tool presented here is not intended to replace conventional, detailed costing methodology. The process described enables "quick look" estimations and assumptions to effectively determine whether an initial concept (with its attendant cost estimating line items) provides focus for major leapfrog improvement. The Cost Charts Users Guide provides a generic sample tutorial, building an approximate understanding of the basic launch system cost factors and their representative magnitudes. This process will enable the user to develop a net "cost (and price) per payload-mass unit to orbit" incorporating a variety of significant cost drivers, supplemental to basic vehicle cost estimates. If acquisition cast and recurring cost factors (as a function of cost per payload-mass unit to orbit) do not meet the predetermined system-profitability goal, the concept in question will be clearly seen as non-competitive. Multiple analytical approaches, and applications of a variety of interrelated assumptions, can be examined in a quick, (on-the-spot) cost approximation analysis as this tool has inherent flexibility. The technique will allow determination of concept conformance to system objectives. C1 NASA, Kennedy Space Ctr, FL 32899 USA. RP Rhodes, RE (reprint author), NASA, Kennedy Space Ctr, FL 32899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 962 EP 967 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200157 ER PT S AU Sawyer, JW Bush, H AF Sawyer, JW Bush, H BE ElGenk, MS TI Experimental investigation of a graphite-composite intertank section for a reusable launch vehicle SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The use of graphite-composites as primary structure is essential for the development of a cost effective single-stage-to-orbit reusable launch vehicle (RLV). A full-scale segment of a graphite-composite intertank was designed and fabricated by an industry team and tested at NASA Langley Research Center as a part of the RLV technology development program. The intertank test component was approximately 3.0 m long by 6.7 m wide and included slightly less than a 90 degrees section of a cylindrical intertank. The test article was fabricated using graphite-bismaelimide composite material and consisted of a hat-stiffened skin with five ring frames. The stiffeners were secondarily bonded to the panel skin and the ring frames were mechanically attached. The test article was loaded to failure with a uniform compression load applied by 21 individually controlled hydraulic actuators. Resistance strain gages, linear variable differential transformers and video cameras were used to measure and record the test results. A linear finite element analysis of the test article and test fixture was performed. The test results verified the structural integrity of the intertank test article up to the design limit load. However, the test article failed in general skin buckling between the ring frames at a load 1.08 times design limit load. This load was considerably lower than the expected failure load. The cause of premature failure is being investigated. Good correlation of the test and analysis results was obtained for loads up to the design limit load. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sawyer, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1007 EP 1019 PG 13 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200164 ER PT S AU Mondt, JF Underwood, M Nesmith, BJ AF Mondt, JF Underwood, M Nesmith, BJ BE ElGenk, MS TI Advanced converter technology evaluation and selection for ARPS SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The three advanced converter technologies for future potential radioisotope power sources for space were evaluated based on mission requirements for proposed NASA planetary missions. Alkali Metal Thermal to Electric Conversion (AMTEC), Stirling Conversion (STC) and Thermal Photovoltaic (TPV) technologies were the three best advanced conversion technologies candidates for low power, similar to 100 watts, space radioisotope power source. General mission requirements were prepared for potential NASA deep space scientific missions as described in the Mission to the Solar System Roadmap, (Elachi 1996). The selection criteria for the conversion technology was prepared based on mission requirements, Safety, Performance (efficiency, specific power & lifetime), Development (cost and schedule risk), Spacecraft Interfaces and Operations and Scalability (150We to 50We to 10We) were the five key converter technology characteristics used to compare and make the selection, AMTEC was selected as the conversion technology for the near term advanced radioisotope power source for potential NASA deep space science missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mondt, JF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1098 EP 1105 PG 8 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200178 ER PT S AU Skinner, D Phillips, JM AF Skinner, D Phillips, JM BE ElGenk, MS TI Launch approval considerations for space nuclear power systems SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Nuclear Safety Launch Approval is the US process by which approval is granted from the Executive Branch for the use of nuclear materials in space. It involves analyses utilizing a combination of theoretical calculation and empirical test data, by which the launch of a space nuclear system is demonstrated to have acceptable consequences in terms of radiological risk. Many factors influence the launch approval process and it's complexity. Historical launch approval examples are discussed as well as considerations for mission design, power source design, launch vehicle selection and spacecraft design which may simplify the analyses for launch approval. Factors which influence the complexity of the analyses as well as factors which can bound the analyses are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Skinner, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-472, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1179 EP 1183 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200190 ER PT S AU Kos, L AF Kos, L BE ElGenk, MS TI The Human Mars Mission: Transportation assessment SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB If funding is available, and for NASA planning purposes, the Human Mars Mission (HMM) is baselined to take place during the 2011 and 2013/2014 Mars opportunities. Two cargo flights will leave for Mars during the first opportunity, one to Mars: orbit and the second to the surface, in preparation for the crew during the following opportunity. Each trans-Mars injection (TMI) stack will consist of a cargo / payload portion (currently coming in at between 65 and 78 mt) and a nuclear thermal propulsion (NTP) stage (currently coming in at between 69 and 77 mt loaded with propellant) for performing the departure Delta Vs to get on to the appropriate Mars trajectories. Three 66,700 N thrust NTP engines comprise the TMI stage for each stack and perform a Delta V ranging from 3580 to 3890 mis as required by the trajectory (with gravity losses and various performance margins added to this for the total TMI Delta V performed). This paper will discuss the current application of this NTP stage to a Human Mars mission, and project what implications a nuclear trans-Earth injection (TEI) stage as well as a bi-modal NTP stage could, mean to a human visit to Mars. C1 NASA, George C Marshall Space Flight Ctr, Preliminary Design Off, Miss Anal Team, Huntsville, AL 35812 USA. RP Kos, L (reprint author), NASA, George C Marshall Space Flight Ctr, Preliminary Design Off, Miss Anal Team, Mail Code PD31, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1206 EP 1211 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200195 ER PT S AU Campbell, JW Taylor, CR AF Campbell, JW Taylor, CR BE ElGenk, MS TI Ground-based laser propulsion for orbital debris removal SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Orbital debris in few-Earth orbit in the size range from 1 to 10 cm in diameter can be detected but not tracked reliably enough to be avoided by spacecraft. It can cause catastrophic damage even to a shielded spacecraft. With adaptive optics, a ground-based pulsed laser ablating the debris surface can produce enough propulsion in several hundred pulses to cause such debris to reenter the atmosphere. A single laser station could remove all of the 1-10 cm debris in three years or less. A technology demonstration of laser space propulsion is proposed which would pave the way for the implementation of such a debris removal system. The cost of the proposed demonstration is comparable with the estimated annual cost of spacecraft operations in the present orbital debris environment. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Campbell, JW (reprint author), NASA, George C Marshall Space Flight Ctr, Mail Stop PS02, Huntsville, AL 35812 USA. NR 0 TC 0 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1212 EP 1217 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200196 ER PT S AU Holt, AC AF Holt, AC BE ElGenk, MS TI International space station technology demonstrations SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB The International Space Station (ISS) has the capability to test and demonstrate, and otherwise assist in the development and validation, of a wide range of advanced technologies. Technology tests and demonstrations for advanced communication systems, closed-loop environmental control systems, advanced power storage and generation systems, advanced electric and electromagnetic propulsion systems, and others are being assessed for inclusion in an ISS Pre-Planned Program Improvement ((PI)-I-3), Technology/Improvement Road map. The (PI)-I-3 road map is an integrated set of technology and improvement requirements for: (1) ISS subsystem upgrades and improvements (addressing maintenance, logistics, sustainability, and enhancement functions), (2) payload hardware technology infusion, (3) ISS/Exploration technology development and tests (dual use/benefits), and (4) Engineering Research and Technology payloads. As examples of the International Space Station's technology testbed capabilities, implementation approaches for three types of propulsion technology demonstrations and research are described: (1) electric and electromagnetic propulsion technologies and systems (NASA Lewis Research Center), (2) technologies and sub-systems for a variable specific impulse (Isp), magnetoplasma rocket (VASIMR), (Advanced Propulsion Lab, Sonny Carter Training Facility, Houston, Tx), and (3) candidates for innovative, deep space propulsion technology research and demonstrations (projections based on NASA Advanced Space Transportation Program, Propulsion Research and other R.&D activities.). C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Holt, AC (reprint author), NASA, Lyndon B Johnson Space Ctr, Code OZ4, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1295 EP 1300 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200207 ER PT S AU Cataldo, RL Borowski, SK AF Cataldo, RL Borowski, SK BE ElGenk, MS TI Requirements for a common nuclear propulsion and power reactor for human exploration missions to Mars SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Requirements for propulsion and power systems capable of achieving a safe, reliable, robust and affordable human Mars exploration mission have been identified. Nuclear systems have been identified that can meet the challenges of short trip times, reduced number of launch vehicles, potential for "all propulsive" maneuvers, abundant in-space power and low mass, volume and deployed area, and energy rich surface power. Reduced total systems cost will also be mandatory to achieve affordable human exploration of Mars. Hence, it is desirable to design a space propulsion and surface power reactor with the greatest degree of commonality as possible with the goal of reducing total system costs. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Cataldo, RL (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1301 EP 1306 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200208 ER PT S AU Wilt, DM Chubb, DL AF Wilt, DM Chubb, DL BE ElGenk, MS TI A review of recent thermophotovoltaic energy conversion technology development at NASA Lewis Research Center SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB NASA Lewis Research Center (LeRC) has had an ongoing research program in TPV since the late 1980's. This effort has included bath in-house research programs on critical components such as photovoltaic cells (PV) and emitter materials, as well as an active contracting effort directed toward system and component development. Of particular note is the in-house development of thin film selective emitters fabricated from rare-earth)yttrium aluminum garners (YAG). Also developed at LeRC is a Monolithic Interconnected Module (MIM) consisting of many small InGaAs cells series interconnected on a single InP substrate. An infrared reflector placed on the rear surface of the substrate returns unabsorbed photons to the emitter for recycling. The current contracted efforts include two TPV system developments by Tecogen, Inc., a solar powered TPV system development, a GaInAsSb cell development and several emitter development efforts (plasma-sprayed selective emitters, flexible SiC and a selective emitting light pipe). C1 NASA, Lewis Res Ctr, Photovoltaic & Space Environm Branch, Cleveland, OH 44135 USA. RP Wilt, DM (reprint author), NASA, Lewis Res Ctr, Photovoltaic & Space Environm Branch, Cleveland, OH 44135 USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1410 EP 1415 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200223 ER PT S AU Ryan, MA Williams, RM Homer, ML Phillips, WM Lara, L Miller, J AF Ryan, MA Williams, RM Homer, ML Phillips, WM Lara, L Miller, J BE ElGenk, MS TI Lifetime modeling of TiN electrodes for AMTEC cells SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB In order to model the lifetime of the electrochemical cell in an Alkali Metal Thermal to Electric Converter (AMTEC), studies of TIN electrodes on beta "-alumina solid electrolytes (BASE) have been made to determine the performance parameters over time. The first of a series of experiments in which TiN electrodes are studied in a Vapor Exposure Test Cell is described here, with preliminary results from electrochemical measurements made on the cell. The TiN electrodes tested here perform well, with minimal degradation over 1000 hours of operation at 850 degrees C. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ryan, MA (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 AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1607 EP 1612 PG 6 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200248 ER PT S AU Caillat, T Fleurial, JP Borshchevsky, A AF Caillat, T Fleurial, JP Borshchevsky, A BE ElGenk, MS TI Development of high efficiency thermoelectric generators using advanced thermoelectric materials SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM - 1998, PTS 1-3: 1ST CONF ON GLOBAL VIRTUAL PRESENCE; 1ST CONF ON ORBITAL TRANSFER VEHICLES; 2ND CONF ON APPLICAT OF THERMOPHYS IN MICROGRAV; 3RD CONF ON COMMERCIAL DEV OF SPACE; 3RD CONF ON NEXT GENERAT LAUNCH SYST; 15TH SYMP ON SPACE NUCL POWER AND PROPULSION SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 1998 Space Technology and Applications International Forum (STAIF-98) - Progress in Expanding the Space Frontier CY JAN, 1998 CL ALBUQUERQUE, NM SP USAF, NASA, New Mexico Space Grant Consortium, Amer Nucl Soc, Trinity Sect, Univ New Mexico, Inst Space & Nucl Power Studies AB Despite their relatively low efficiency, thermoelectric generators are used in a limited number of industrial applications where they are preferred to other energy conversion devices because of their high reliability, low maintenance and long life, in particular when considering harsh environments. New more efficient thermoelectric materials and devices are needed to expand the range of application of thermoelectric generators. Several new terrestrial applications requiring higher efficiency generators have been recently described in the literature. Heat sources for these applications range from low grade waste heat at 325-350 K up to 850 to 1100 K for heat recovery from processing plants of combustible solid waste. Commercial thermoelectric generators are usually built using Bi2Te3- or PbTe-based alloys depending on the maximum hot side temperature. A new approach consisting of using new high performance thermoelectric materials developed at the Jet Propulsion Laboratory (JPL) and operating the generator over a larger temperature difference is presented. By using novel segmented legs based on a combination of state-of-the-art thermoelectric materials and p-type Zn4-xCdxSb3 alloys, p-type CeFe4Sb12-based alloys and n-type CoSb3-based alloys, an increase in the thermoelectric materials conversion efficiency of about 60% is expected compared to Bi2Te3- and PbTe-based generators. The maximum thermoelectric materials efficiency will be about 20% for the optimum generator configuration Various issues related to the fabrication of new segmented legs, including bonding and temperature stability tests, will be briefly discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Caillat, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 2 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-747-2 J9 AIP CONF PROC PY 1998 IS 420 BP 1647 EP 1651 PG 5 WC Engineering, Aerospace; Remote Sensing; Physics, Applied SC Engineering; Remote Sensing; Physics GA BK50G UT WOS:000072374200254 ER PT S AU Seery, BD Smith, EP AF Seery, BD Smith, EP BE Bely, PY Breckinridge, JB TI NASA's next generation space telescope visiting a time when galaxies were young SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE active optics; next generation space telescope; deployables; detectors AB With the discovery of galaxies that existed when the universe was very young (approximately 5 percent of its current age), of planets not in our own solar system, and with the tantalizing evidence that the conditions for life may have existed within our solar system on planets or moons outside of the earth system, the past year has seen an explosion of interest in astronomy. In particular, a new era of exploration and understanding seems imminent, where the connection between the existence for the conditions of life will be connected to the origin of galaxies, stars and planets within the Universe. Who knows where this quest for knowledge will take us? RP Seery, BD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 5 Z9 5 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 2 EP 13 DI 10.1117/12.324425 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200001 ER PT S AU Mather, JC Smith, EP Stockman, HS AF Mather, JC Smith, EP Stockman, HS BE Bely, PY Breckinridge, JB TI Scientific metrics for the next generation space telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE infrared; space telescopes AB As part of NASA's Origins theme, the Next Generation Space Telescope will investigate the origin of galaxies, stars, and planets, using infrared observations with a cooled telescope. Located at L2 or farther from the Earth, it will be protected from near-Earth hazards and will be radiatively cooled to allow background limited observations. The scientific goals were described in the "HST and Beyond report," and the proposed NGST approach in "Visiting A Time When Galaxies Were Young." It is clear that an 8 m class telescope in deep space would be a tremendous tool that would lead to surprising discoveries. It will also require revolutionary changes in technology and management approaches, since the budget must be small compared with the Hubble Space Telescope. A major challenge is to develop a scientific performance metric that represents a consensus on the importance of various engineering parameters, like accuracy, field of view, sensitivity, spatial and spectral resolution, temperature, vibration, stability, and so forth. Such a metric could be used for choosing instrument or telescope configurations, or for selecting or paying a contractor in the performance based contracting approach now in vogue. Ideally it could also be used for optimizing the cost of the mission, ensuring that effort is proportionate to benefit. The scientific, mathematical, and social aspects of our approach will be reported. C1 NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Greenbelt, MD 20771 USA. RP Mather, JC (reprint author), NASA, Goddard Space Flight Ctr, Infrared Astrophys Branch, Code 685 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 32 EP 38 DI 10.1117/12.324467 PN 1-2 PG 7 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200004 ER PT S AU Smith, EP Mather, JC Stockman, HS Bely, PY Stiavelli, M Burg, R AF Smith, EP Mather, JC Stockman, HS Bely, PY Stiavelli, M Burg, R BE Bely, PY Breckinridge, JB TI The next generation space telescope design reference mission SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ AB The Next Generation Space Telescope (NGST) Design Reference Mission (DRM) represents a suite of potential astronomical programs and targets along with their expected physical properties (e.g., number density, brightness), and desired observation modes (e.g., wavelength band, spectral resolution, number of revisits). This broad science program is being used to drive the observatory design in a way as fundamental as traditional engineering parameters (power, mass, etc.). Astronomers use the DRM to communicate their desires in a quantitative fashion to the engineers who will eventually construct the observatory. The DRM is also the primary tool used to measure the relative value of NGST mission architectures and technological readiness of the program. Specifically, the fraction of the DRM completed by a given observatory configuration in a given time is, to first order, a measure of the value of the design. Those designs which complete a higher fraction of the observations listed below are more capable than those that complete lesser fractions. C1 NASA, Goddard Space Flight Ctr, Lab Astron & Astrophys, Greenbelt, MD 20771 USA. RP Smith, EP (reprint author), NASA, Goddard Space Flight Ctr, Lab Astron & Astrophys, Code 681 685, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 39 EP 45 DI 10.1117/12.324477 PN 1-2 PG 7 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200005 ER PT S AU Jacobson, DN Nein, M Craig, L Schunk, G Rakoczy, J Cloyd, D Ricks, E Hadaway, J Redding, D Bely, P AF Jacobson, DN Nein, M Craig, L Schunk, G Rakoczy, J Cloyd, D Ricks, E Hadaway, J Redding, D Bely, P BE Bely, PY Breckinridge, JB TI Design of a large lightweight space telescope optical system for the Next Generation Space Telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE Optical Telescope Assembly; NGST; optics; primary mirror; origins AB The Next Generation Space Telescope (NGST) program is currently conducting a pre-Phase A study to prove feasibility of design, show that the design can be implemented within cost guidelines, and meet the requirements of the science community. In an effort to achieve the science community's goals as outlined in the "HST and Beyond" report, the NGST team has developed a Government "yardstick" design of an 8-meter aperture segmented-mirror telescope which would be launched in an Atlas IIAS launch vehicle into the L2 (Lagrange Point) orbit. This paper will discuss the design of the Optical Telescope Assembly (OTA) and the various issues and complications of designing lightweight optics to be placed in the environment that the NGST will encounter both during launch and during its mission at L2. The OTA must be lightweight but also structurally able to withstand the launch environment and transfer to the L2 orbit. The OTA must be optically stable at L2 to provide high quality science at the cryogenic temperatures which it will experience. The OTA segmented petal mirror concept (Figure 1), is predicated on the development of lightweight optics which can either be manipulated to achieve and maintain a desired figure or be rigid enough so that change in shape is only necessary for phasing and alignment. Wavefront control is accomplished with a deformable quaternary mirror. The secondary mirror structural mast must also be rigid with frequency responses decoupled from spacecraft modes in order to maintain decenter and despace within several microns. The ultimate design of the OTA will eventually be provided by a contract team beginning sometime in the 2003/04 timeframe. The effort being accomplished today will serve as a stepping stone to proving OTA design feasibility and technology readiness to begin contractor design and development. This paper provides an overview of the NASA OTA design effort. It investigates material considerations for the OTA, structural design of the primary mirror and secondary support structure, thermal design, optical prescription/design, and the use of integrated optical modeling in development of the NASA design for the NGST OTA. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Jacobson, DN (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 2 Z9 2 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 74 EP 88 DI 10.1117/12.324514 PN 1-2 PG 15 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200009 ER PT S AU Mosier, G Femiano, M Ha, K Bely, P Burg, R Redding, D Kissil, A Rakoczy, J Craig, L AF Mosier, G Femiano, M Ha, K Bely, P Burg, R Redding, D Kissil, A Rakoczy, J Craig, L BE Bely, PY Breckinridge, JB TI An integrated modeling environment for systems-level performance analysis of the Next Generation Space Telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE integrated modeling; jitter; vibration isolation; controls-structures interaction AB All current concepts for the NGST are innovative designs which present unique systems-level challenges. The goals are to outperform existing observatories at a fraction of the current price/performance ratio. Standard practices for developing systems error budgets, such as the "root-sum-of-squares" error tree, are insufficient for designs of this complexity. Simulation and optimization are the tools needed for this project; in particular tools that integrate controls, optics, thermal and structural analysis, and design optimization. This paper describes such an environment which allows sub-system performance specifications to be analyzed parametrically, and includes optimizing metrics that capture the science requirements. The resulting systems-level design trades are greatly facilitated, and significant cost savings can be realized. This modeling environment, built around a tightly integrated combination of commercial-off-the-shelf and in-house-developed codes, provides the foundation for linear and non-linear analysis in both the time and frequency-domains, statistical analysis, and design optimization. It features an interactive user interface and integrated graphics that allow highly-effective, real-time work to be done by multidisciplinary design teams. For the NGST, it has been applied to issues such as pointing control, dynamic isolation of spacecraft disturbances, wavefront sensing and control, on-orbit thermal stability of the optics, and development of systems-level error budgets. In this paper, results are presented from parametric trade studies that assess requirements for pointing control, structural dynamics, reaction wheel dynamic disturbances, and vibration isolation. These studies attempt to define requirements bounds such that the resulting design is optimized at the systems level, without attempting to optimize each subsystem individually. The performance metrics are defined in terms of image quality, specifically centroiding error and RMS wavefront error, which directly links to science requirements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mosier, G (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 89 EP 97 DI 10.1117/12.324524 PN 1-2 PG 9 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200010 ER PT S AU Coulter, DR AF Coulter, DR BE Bely, PY Breckinridge, JB TI Technology development for the next generation space telescope: an overview SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE NGST; telescope technology; large optics; cryogenic optics AB NASA has embarked on the development of the Next Generation Space Telescope (NGST). The NGST is envisioned to be a large aperture (6-10m) deployable infrared telescope with sensitivity 1000 times greater than any currently existing or planned infrared telescope. The scientific goals of NGST include imaging the earliest galaxies and proto-galaxies which formed following the "big bang". Several studies have concluded that the mission is feasible within the proposed cost ifa well planned, aggressive technology development effort is implemented early in the development phase. This paper presents an overview of the technology program NASA is pursuing to provide the necessary technology to enable an exciting, affordable NGST mission to launch early in the next century. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Coulter, DR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 9 Z9 9 U1 1 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 106 EP 113 DI 10.1117/12.324426 PN 1-2 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200012 ER PT S AU Wooldridge, E Powers, C AF Wooldridge, E Powers, C BE Bely, PY Breckinridge, JB TI Evaluation of thin films for the next generation space telescope (NGST) sunshield SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE space environmental effects; thermal control film; Next Generation Space Telescope; sunshield AB The optics and detectors for the Next Generation Space Telescope (NGST) will operate at IR wavelengths between 0.5 and 30 mu m. To accomplish the requirements set for NGST, the telescope and science module will have to operate at temperatures below 60 K. To achieve cryogenic temperatures, several of the current designs for NGST use a large deployable sunshield to passively cool the telescope. The current concepts for the sunshield consist of 4 to 6 layers of thin film thermal control material supported by deployable struts. The sunshield will need to be about 30 by 15 meters, and will have to survive for 10 years in a deep space environment. A program has been initiated to identify thin film materials that will meet the NGST sunshield requirements. The first step in this program is a literature search that has identified potential thin film materials and coatings for the sunshield. The second step will involve an initial screening of these materials, followed by more rigorous testing of selected candidate materials. This testing will characterize the mechanical, thermal and optical properties before and after exposure to a simulated NGST sunshield environment In addition, because the sunshield will be folded and stowed before launch, the candidate materials will be folded, stowed and unfolded (deployed) before exposure to the simulated environment. C1 NASA, Goddard Space Flight Ctr, Mech Syst Ctr, Greenbelt, MD 20771 USA. RP Wooldridge, E (reprint author), NASA, Goddard Space Flight Ctr, Mech Syst Ctr, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 134 EP 140 DI 10.1117/12.324522 PN 1-2 PG 7 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200015 ER PT S AU Davila, PS Lowman, AE Wilson, ME Boucarut, RA LeBoeuf, CM Redding, DC Young, EW AF Davila, PS Lowman, AE Wilson, ME Boucarut, RA LeBoeuf, CM Redding, DC Young, EW BE Bely, PY Breckinridge, JB TI Optical design of the developmental cryogenic active telescope testbed SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE active optics; wavefront sensing; deformable mirror; segmented aperture; optical design; NGST AB In the summer of 1996, three study teams developed conceptual designs and mission architectures for the Next Generation Space Telescope (NGST)(1,2). All three conceptual designs provided scientific capabilities that met or surpassed those envisioned by the Hubble Space Telescope (HST) and Beyond Committee(3). Each group highlighted areas of technology development that need to be further advanced to meet the goals of the NGST mission. The most important areas for future study included: deployable structures, lightweight optics, cryogenic optics and mechanisms, passive cooling, and on-orbit closed loop wavefront sensing and control. NASA and industry are currently planning to develop a series of ground testbeds and validation nights to demonstrate many of these technologies. The Developmental Cryogenic Active Telescope Testbed (DCATT) is a system level testbed to be developed at Goddard Space Flight Center in three phases over an extended period of time. This testbed will combine an actively controlled telescope with the hardware and software elements of a closed loop wavefront sensing and control system to achieve diffraction limited imaging at 2 microns. We will present an overview of the system level requirements, a discussion of the optical design, and results of performance analyses for the Phase 1 ambient concept for DCATT. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Davila, PS (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 U1 1 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 141 EP 152 DI 10.1117/12.324523 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200016 ER PT S AU Young, EW Wilson, M Davila, PS Eichhorn, W LeBoeuf, C Redding, D Lowman, AE AF Young, EW Wilson, M Davila, PS Eichhorn, W LeBoeuf, C Redding, D Lowman, AE BE Bely, PY Breckinridge, JB TI Performance analysis of the developmental cryogenic active telescope testbed (DCATT) SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE NGST; active optics; adaptive optics; deformable mirror; error budget AB Various efforts are underway to demonstrate hardware for the Next Generation Space Telescope (NGST). One such effort is the development of the DCATT testbed. This testbed is an NGST effort geared to demonstrating in hardware the end-to-end system functionality. The system includes a segmented telescope, active optics subsystem with a deformable mirror (DM), and a wavefront sensor. The degree to which the DCATT can demonstrate this functionality depends crucially on its performance. A system performance analysis of this testbed is presented. The analysis is based on the design of the DCATT developed by Goddard and JPL. In the analysis, the performance of the system as a function of key system factors is calculated. These factors include the following: control, environmental, fabrication, alignment, and design. The performance after correction by the DM is required to be diffraction-limited at a wavelength of 2.0 microns. The flowdown of this performance is called the corrected error budget. To fully characterize the testbed performance as a system, one must develop a budget for the performance of the system before action of the DM. The flowdown of this performance is called the uncorrected error budget. The top line of this budget is related to the correction capability of the DM. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Young, EW (reprint author), NASA, Goddard Space Flight Ctr, Code 717, Greenbelt, MD 20771 USA. NR 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 161 EP 175 DI 10.1117/12.324526 PN 1-2 PG 15 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200018 ER PT S AU Kimble, RA Woodgate, BE Bowers, CW Kraemer, SB Kaiser, ME Gull, TR Heap, SR Danks, AC Boggess, A Green, RF Hutchings, JB Jenkins, EB Joseph, CL Linsky, JL Maran, SP Moos, HW Roesler, F Timothy, JG Weistrop, DE Grady, JF Loiacono, JJ Brumfield, MD Feinberg, LD Krebs, CA Meyer, WW Hood, DF Argabright, VS Hetlinger, JC Stocker, RB Woodruff, RA Baum, SA Hartig, GF Bohlin, RC Clampin, M Ferguson, HC Goudfrooij, P McGrath, M Lindler, DJ Beck, TL Feggans, JK Plait, PC Sandoval, JL Hill, RS Collins, NR Cornett, RH Fowler, WB Hill, RJ Landsman, WB Malumuth, EM Crenshaw, DM Robinson, RD Valenti, JA AF Kimble, RA Woodgate, BE Bowers, CW Kraemer, SB Kaiser, ME Gull, TR Heap, SR Danks, AC Boggess, A Green, RF Hutchings, JB Jenkins, EB Joseph, CL Linsky, JL Maran, SP Moos, HW Roesler, F Timothy, JG Weistrop, DE Grady, JF Loiacono, JJ Brumfield, MD Feinberg, LD Krebs, CA Meyer, WW Hood, DF Argabright, VS Hetlinger, JC Stocker, RB Woodruff, RA Baum, SA Hartig, GF Bohlin, RC Clampin, M Ferguson, HC Goudfrooij, P McGrath, M Lindler, DJ Beck, TL Feggans, JK Plait, PC Sandoval, JL Hill, RS Collins, NR Cornett, RH Fowler, WB Hill, RJ Landsman, WB Malumuth, EM Crenshaw, DM Robinson, RD Valenti, JA BE Bely, PY Breckinridge, JB TI The on-orbit performance of the Space Telescope Imaging Spectrograph SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE ultraviolet; visible; space instrumentation; spectrograph; HST; STIS; MAMA; CCD AB The Space Telescope Imaging Spectrograph (STIS) is a second-generation instrument for the Hubble Space Telescope (HST), designed to cover the 115-1000 nm wavelength range in a versatile array of spectroscopic and imaging modes that take advantage of the angular resolution, unobstructed wavelength coverage, and dark sky offered by the HST. STIS was successfully installed into HST in 1997 February and has since completed a year of orbital checkout, calibration, and scientific observing. In this paper, we brielfy describe the STIS instrument and highlight the new capabilities that it brings to HST, illustrate those capabilities with examples drawn from the first year of STIS observing, and describe at a top level the on-orbit performance of the STIS hardware. We also point the reader to related papers that describe particular aspects of the STIS design, performance, or scientific usage in more detail. C1 Goddard Space Flight Ctr, Code 681, STIS Invest Definit Team, Greenbelt, MD 20771 USA. RP Kimble, RA (reprint author), Goddard Space Flight Ctr, Code 681, STIS Invest Definit Team, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012 OI Gull, Theodore/0000-0002-6851-5380; NR 0 TC 17 Z9 17 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 188 EP 202 DI 10.1117/12.324433 PN 1-2 PG 15 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200021 ER PT S AU Gull, TR Woodgate, BE Kimble, RA Bowers, CW Kraemer, SB Kaiser, ME Bohlin, RC Hulbert, SJ Shaw, RA Feggans, K Lindler, DJ Sandoval, JL Hill, RS Collins, N Brown, TM Valenti, JA AF Gull, TR Woodgate, BE Kimble, RA Bowers, CW Kraemer, SB Kaiser, ME Bohlin, RC Hulbert, SJ Shaw, RA Feggans, K Lindler, DJ Sandoval, JL Hill, RS Collins, N Brown, TM Valenti, JA BE Bely, PY Breckinridge, JB TI STIS on-orbit testing: Limiting magnitudes, spectral sensitivity, thermal flexure and MAMA time-tagging SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE ultraviolet; visible; space; HST; contamination; thermal motion; sensitivity; calibration AB The Space Telescope Imaging Spectrograph (STIS), installed into the Hubble Space Telescope (HST) during the Second Servicing Mission (SSM) in February 1997, has undergone the required Servicing Mission Orbital Verification (SMOV). The overall sensitivity of STIS is summarized for direct imagery in the visible with the Charge Coupled Device (CCD), the Near Ultraviolet Multi-Anode Microchannel-Array (NW MAMA) and the Far Ultraviolet MAMA (FUV MAMA) detectors and likewise for the spectroscopic modes. The FUV MAMA has exceedingly low background (globally similar to 6 events/second for the 2048 x 2048 high resolution (HTRES) elements). The NW MAMA has a higher, temperature-dependent background (similar to 600 to 2000 events/second globally) due to window phosphorescence. The principal gains of the CCD over WFPC2 for limiting imaging sensitivity are: high quantum efficiency (peaking above 60%), wide bandpass (unfiltered), low dark current (similar to 6 electrons/pixel/hour) and low readout-noise (similar to 4 electrons rms). The CCD, like the WFPC2 CCDs, must be annealed periodically to heal the hot pixels generated by radiation hits. Throughput of all modes has been stable at the 1% level or better except for the far ultraviolet (G140L), where sensitivity is dropping slowly across the order, but more rapidly below the Lyman alpha (<120 nm), and beyond 150 nm. This loss in sensitivity may be due to contamination similar to that which affected the first generation HST instruments. The thermal environment for STIS is warmer than specified in the HST Interface Control Document with the result that the back end of the STIS optical bench is not under positive thermal control. Temperature swings occur due to the spacecraft solar orientation and also due to power cycling of the MAMA low voltage power supplies that are turned off during orbits that encounter the South Atlantic Anomaly. Some motion of spectral and direct image formats occurs on the detector that is correlatible with changing aft bulkhead temperature and changes in external heatloads. The MAMA detectors are capable of time-tagging photon events within 125 microsecond resolution. The Crab Pulsar was used as a time standard and demonstrates the desired performance. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Gull, TR (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. RI Gull, Theodore/D-2753-2012; Woodgate, Bruce/D-2970-2012; OI Gull, Theodore/0000-0002-6851-5380; Brown, Thomas/0000-0002-1793-9968 NR 0 TC 1 Z9 1 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 203 EP 214 DI 10.1117/12.324443 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200022 ER PT S AU Leviton, DB Tsvetanov, Z Woodruff, RA Mooney, TA AF Leviton, DB Tsvetanov, Z Woodruff, RA Mooney, TA BE Bely, PY Breckinridge, JB TI Design and specification of optical bandpass filters for Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE bandpass filters; ramp filters; color filter glass; spectral transmittance; focal shift; parfocality; transmitted wavefront; passband; out-of-band rejection AB Advanced optical bandpass filters for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) have been developed on a filter-by-filter basis through detailed studies which take into account the instrument's science goals, available optical filter fabrication technology, and developments in ACS's charge-coupled-device detector technology. These filters include a subset of filters for the Sloan Digital Sky Survey (SDSS) which are optimized for astronomical photometry using today's charge-coupled-devices (CCD's). In order for ACS to be truly advanced, these filters must push the state-of-the-art in performance in a number of key areas at the same time. Important requirements for these filters include outstanding transmitted wavefront, high transmittance, uniform transmittance across each filter, spectrally structure-free bandpasses, exceptionally high out of band rejection, a high degree of parfocality, and immunity to environmental degradation. These constitute a very stringent set of requirements indeed, especially for filters which are up to 90 mm in diameter. The highly successful paradigm in which final specifications for flight filters were derived through interaction amongst the ACS Science Team, the instrument designer, the lead optical engineer, and the filter designer and vendor is described. Examples of iterative design trade studies carried out in the context of science reeds and budgetary and schedule constraints are presented. An overview of the final design specifications for the ACS bandpass and ramp filters is also presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. NR 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 308 EP 320 DI 10.1117/12.324531 PN 1-2 PG 13 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200032 ER PT S AU Leviton, DB Boucarut, RA Bush, FD Content, DA Keski-Kuha, RA Kral, C Krebs, CA Madison, TJ Mehalick, KI Miner, LA Norton, TA Petrone, P Puc, BP Standley, C Tsvetanov, Z Varosi, F AF Leviton, DB Boucarut, RA Bush, FD Content, DA Keski-Kuha, RA Kral, C Krebs, CA Madison, TJ Mehalick, KI Miner, LA Norton, TA Petrone, P Puc, BP Standley, C Tsvetanov, Z Varosi, F BE Bely, PY Breckinridge, JB TI Optical metrology for the filter set for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE transmissometry; out-of-band rejection; index of refraction; focal shift; transmitted wavefront; interferometry AB The Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) employs a wide variety of spectral filtration components including narrow band, medium band, wide band, and far ultraviolet (FUV) long pass filters, spatially-variable filters (ramp filters), VIS/IR polarizers, NUV polarizers, FUV prisms, and a grism. These components are spread across ACS's Wide Field, High Resolution, and Solar Blind channels which provide diffraction-limited imaging of astronomical targets using aberration-correcting optics which remove most aberrations from HST's Optical Telescope Assembly(OTA). In order for ACS to be truly advanced, these filters must push the state-of-the-art in performance in a number of key areas at the same time. Important requirements which these filters must meet include outstanding transmitted wavefront, high transmittance, uniform transmittance across each filter, spectrally structure-free bandpasses, exceptionally high out of band rejection, and a high degree of parfocality. These constitute a very stringent set of requirements indeed, especially for filters which are up to 90 mm in diameter. The development of unique optical metrology stations used to demonstrate that each ACS filter will meet its design specifications is discussed. Of particular note are specially-designed spectral transmissometers and interferometers. C1 NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. RP Leviton, DB (reprint author), NASA, Goddard Space Flight Ctr, Opt Branch, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 U1 1 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 350 EP 360 DI 10.1117/12.324536 PN 1-2 PG 11 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200036 ER PT S AU Boucarut, RA Leviton, DB AF Boucarut, RA Leviton, DB BE Bely, PY Breckinridge, JB TI Broadband interferometer for measuring transmitted wavefronts of optical band pass filters for Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE interferometry; optical filters; wavefront; Advanced Camera for Surveys AB The transmitted wavefronts of optical filters for the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) are characterized using the Wildly and Openly Modified Broadband Achromatic Twyman Green (WOMBAT) Interferometer developed in the NASA/GSFC Optics Branch's Diffraction Grating Evaluation Facility (DGEF).(1) Because only four of thirty-three of ACS's optical bandpass filters transmit the 633 nm light of most commercial interferometers, a broadband interferometer is required to verify specified transmitted wavefront of ACS filters. WOMBAT's design is a hybrid of the BAT(2) interferometer developed for JPL used for HST Wide field and Planetary Camera II (WF/PC-2) filters and a WYKO 400 phase shifting interferometer. It includes a broadband light source, monochromator, off-axis, parabolic collimating and camera mirrors, an aluminum-coated fused silica beamsplitter, flat retroreflecting mirrors for the test and reference arms, and a UV-sensitive CCD camera. An outboarded, piezo-electric phase shifter holds the flat mirror in the interferometer's reference arm. The interferometer is calibrated through interaction between the WYKO system's software and WOMBAT hardware for the test wavelength of light entering the beamsplitter. Phase-shifted interferograms of the filter mounted in the test arm are analyzed using WYKO's Vision for Optical Testing(R) software. Filters as large as 90 mm in diameter have been measured over a wavelength range from 200 to 1100 nm with a sensitivity of lambda/200 rms at lambda = 633 nm. Results of transmitted wavefront measurements are shown for ACS fixed bandpass and spatially-variable bandpass filters for a variety of wavelengths. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Boucarut, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 377 EP 388 DI 10.1117/12.324539 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200039 ER PT S AU Krebs, C La Jeunesse, T Ford, H AF Krebs, C La Jeunesse, T Ford, H BE Bely, PY Breckinridge, JB TI Program management of the HST Advanced Camera for Surveys: A new approach SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE HST; ACS; management AB The Advanced Camera for Surveys (ACS), which will be installed on-orbit in I-IST during the 1999 Servicing Mission, is being developed jointly by the Johns Hopkins University (JHU), Ball Aerospace & Technologies Corporation, and NASA Goddard Space Flight Center (GSFC). On ACS, GSFC has contracted separately to JHU for the Principal Investigator (PI) and his science team and to Ball for development and fabrication of the instrument. In addition, GSFC is providing significant amounts of flight hardware. Led jointly by the PI, the Ball Program Manager, and the GSFC Technical Officer, an integrated product team approach has been implemented that includes members from all three organizations, ensuring an integrated approach to meeting the instrument objectives. An innovative, performance-based contracting structure has been implemented that reflects the dual objectives of meeting the science requirements within the cost and schedule constraints. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krebs, C (reprint author), NASA, Goddard Space Flight Ctr, Code 550, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 444 EP 449 DI 10.1117/12.324428 PN 1-2 PG 6 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200044 ER PT S AU Fanson, J Fazio, G Houck, J Kelly, T Rieke, G Tenerelli, D Whitten, M AF Fanson, J Fazio, G Houck, J Kelly, T Rieke, G Tenerelli, D Whitten, M BE Bely, PY Breckinridge, JB TI The Space Infrared Telescope Facility (SIRTF) SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE telescope; cryogenic; infrared; astronomy; astrophysics; Great Observatory AB This paper describes the design of the Space Infrared Telescope Facility (SIRTF) as the project enters the detailed design phase. SIRTF is the fourth of NASA's Great Observatories, and is scheduled for launch in December 2001. SIRTF provides background limited imaging and spectroscopy covering the spectral range from 3 to 180 mu m, complementing the capabilities of the other Great Observatories - the Hubble Space Telescope (HST), the Advanced X-ray Astrophysics Facility (AXAF), and the Compton Gamma Ray Observatory (CGRO). SIRTF will be the first mission to combine the high sensitivity achievable from a cryogenic space telescope with the imaging and spectroscopic power of the new generation of infrared detector arrays. The scientific capabilities of this combination are so great that SIRTF was designated the highest priority major mission for all of US astronomy in the 1990s. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fanson, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 42 Z9 43 U1 1 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 478 EP 491 DI 10.1117/12.324471 PN 1-2 PG 14 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200048 ER PT S AU Woodgate, BE AF Woodgate, BE BE Bely, PY Breckinridge, JB TI A 30-meter diameter telescope in space SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE space telescope; Lagrangian orbits; solar sailing AB A large area telescope of diameter 30 meters may be constructed as a set of multiple parallel coelostats, with flat mirrors feeding into a single telescope forming multiple images. These images may then be recombined into a single image (Woodgate, 1991). The flat mirror array must be separated by over a kilometer from the combining telescope. In space this requires that the two portions should preferably maintain a fixed direction and similar spacing between them during an exposure. A low consumable method suitable for a Lagrangian halo orbit would be to use solar radiation pressure for controlled balance relative to the gravitational field for station keeping, and for attitude control. Arrangements of controllable solar sails are discussed and shown to have sufficient thrust. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20071 USA. RP Woodgate, BE (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20071 USA. RI Woodgate, Bruce/D-2970-2012 NR 0 TC 0 Z9 0 U1 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 561 EP 574 DI 10.1117/12.324478 PN 1-2 PG 14 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200055 ER PT S AU Koch, D Borucki, W Webster, L Dunham, E Jenkins, J Marriott, J Reitsema, H AF Koch, D Borucki, W Webster, L Dunham, E Jenkins, J Marriott, J Reitsema, H BE Bely, PY Breckinridge, JB TI Kepler: a space mission to detect earth-class exoplanets SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE earth-class planets; extrasolar planets; photometry; planet detection; transit method AB With the detection of giant extrasolar planets and the quest for life on Mars, there is heightened interest in finding earth-class planets, those that are less than ten earth masses and might be life supporting. A space-based photometer has the ability to detect the periodic transits of earth-class planets for a wide variety of spectral types of stars. From the data and known type of host star, the orbital semi-major axis, size and characteristic temperature of each planet can be calculated. The frequency of planet formation with respect to spectral type and occurrence for both singular and multiple-stellar systems can be determined. A description is presented of a one-meter aperture photometer with a twelve-degree field of view and a focal plane of 21 CCDs. The photometer would continuously and simultaneously monitor 160,000 stars of visual magnitude less than or equal to 14. Its one-sigma system sensitivity for a transit of a twelfth magnitude solar-like star by a planet of one-earth radius would be one part in 50,000. It is anticipated that about 480 earth-class planets (0.5 less than or equal to M less than or equal to 10 M+) would be detected along with 140 giant planets in transit and 1400 giant planets by reflected light. Densities could be derived for about seven cases where the planet is seen in transit and radial velocities are measurable. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Koch, D (reprint author), NASA, Ames Res Ctr, MS 245-6, Moffett Field, CA 94035 USA. NR 0 TC 46 Z9 46 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 599 EP 607 DI 10.1117/12.324482 PN 1-2 PG 9 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200059 ER PT S AU Bicay, MD Werner, MW Latter, WB Simmons, LL AF Bicay, MD Werner, MW Latter, WB Simmons, LL BE Bely, PY Breckinridge, JB TI Space InfraRed Telescope Facility (SIRTF) enters development SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE SIRTF; space telescopes; infrared astronomy AB The Space InfraRed Telescope Facility (SIRTF), the last of NASA's "Great Observatories," is entering its development phase. Ongoing advances in infrared detector technology, coupled with innovative choices in orbit and system architecture, have maintained the vitality of SIRTF's scientific capability at a small fraction of the original development cost. The great sensitivity of SIRTF and its high observing efficiency promise to yield a rich legacy of science results. SIRTF is on a fast-track development schedule, with launch in December 2001. While the current baseline calls for a minimum 2.5-year cryogenic lifetime, recent programmatic and engineering developments suggest that a 5-year lifetime is within reach. More than 75 percent of the SIRTF observing time will be available to the general community. We summarize the scientific capabilities and the technical specifications for the mission, including descriptions of the three-instrument payload. We will focus on the SIRTF science operations concepts, and describe SIRTF's seven observing modes - the means by which the community will interface with the Observatory. The pre- and post-launch user services available at the SIRTF Science Center will also be presented. We include a listing of events likely to be of interest to potential SIRTF users between now and launch. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bicay, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 264-707, Pasadena, CA 91109 USA. NR 0 TC 5 Z9 5 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 653 EP 664 DI 10.1117/12.324432 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200064 ER PT S AU Yu, W AF Yu, W BE Bely, PY Breckinridge, JB TI Very high-resolution space telescope using the Earth atmosphere as the objective lens SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE space telescope; atmosphere; planet; Earth; high resolution AB Telescopes are critical elements of NASA's space program. Very high resolution telescopes are needed to study planets of neighboring stellar systems and life beyond earth. Telescope resolution is limited by aperture diameter but current technology limits telescope apertures to about 10-meters in diameter. The Earth's atmosphere refracts sunlight such that the sun's image appears about a half degree above its real position during sunset. If we could build a space telescope using the Earth's atmosphere as an objective lens the aperture of such a space telescope would be the diameter of the earth. Telescope resolution could be enhanced by up to seven orders of magnitude and would enable detailed images of planets in far away stellar systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yu, W (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 665 EP 669 PN 1-2 PG 5 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200065 ER PT S AU Lowman, AE Macenka, SA Redding, DC Basinger, SA AF Lowman, AE Macenka, SA Redding, DC Basinger, SA BE Bely, PY Breckinridge, JB TI Infrared Telescope Technology Testbed primary mirror test results SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE SIRTF; space optics; optical testing; optical fabrication; beryllium AB An 85 cm aperture beryllium minor was fabricated as part of the Infrared Telescope Technology Testbed (ITTT), a facility to which the SIRTF flight telescope will be traceable. The ITTT was developed to demonstrate that diffraction-limited performance at a wavelength of 6.5 mu m is attainable from an ultra-lightweight meter-class beryllium telescope operating at a temperature of 5.5K. Cryo-null figuring was employed to meet the requirements for the shape of the primary mirror at its operating temperature over an aperture of 79cm. The results of this process will be presented, including the repeatability of the surface through cryogenic temperature cycling. Modeling of system performance using the residual figure error will be described. Image-based methods were used to characterize a turned up edge that is too steep to be measured with an interferometer. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lowman, AE (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 727 EP 734 DI 10.1117/12.324491 PN 1-2 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200071 ER PT S AU Redding, D Basinger, S Lowman, AE Kissil, A Bely, P Burg, R Lyon, R Mosier, G Femiano, M Wilson, M Schunk, G Craig, L Jacobson, D Rakoczy, J Hadaway, J AF Redding, D Basinger, S Lowman, AE Kissil, A Bely, P Burg, R Lyon, R Mosier, G Femiano, M Wilson, M Schunk, G Craig, L Jacobson, D Rakoczy, J Hadaway, J BE Bely, PY Breckinridge, JB TI Wavefront sensing and control for a Next Generation Space Telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ AB The Next Generation Space Telescope will depart from the traditional means of providing high optical quality and stability, namely use of massive structures. Instead, a benign orbital environment will provide stability for a large, flexible, lightweight deployed structure, and active wavefront controls will compensate misalignments and figure errors induced during launch and cool-down on orbit. This paper presents a baseline architecture for NGST wavefront controls, including initial capture and alignment, segment phasing, wavefront sensing and deformable mirror control. Simulations and analyses illustrate expected scientific performance with respect to figure error, misalignments, and thermal deformation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Redding, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Lyon, Richard/D-5022-2012 NR 0 TC 33 Z9 35 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 758 EP 772 DI 10.1117/12.324494 PN 1-2 PG 15 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200074 ER PT S AU Breckinridge, JB Meinel, AB Meinel, MP AF Breckinridge, JB Meinel, AB Meinel, MP BE Bely, PY Breckinridge, JB TI Inflation-deployed camera and hyper-thin mirrors SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE telescopes; space optics; adaptive optics; optical testing; hyper-thin mirrors; two-stage optics AB Inflatable optics have the potential for a large reduction in launch mass and volume, but they involve significant challenges to achieve the wavefront accuracy required for diffraction-limited operation in the visible and near IR. Current studies identify two major subsets of this topic: 1) inflation-deployed structures with a monolithic, but rolled, hyper-thin primary mirror and 2) an inflatable structure and inflatable membrane primary minor. We address the current state of the art, the challenges involved, and a program development plan. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Breckinridge, JB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 126-244, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 U1 2 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 780 EP 787 DI 10.1117/12.324496 PN 1-2 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200076 ER PT S AU Montgomery, EE Zeiders, GW AF Montgomery, EE Zeiders, GW BE Bely, PY Breckinridge, JB TI The case for segmentation of the primary mirror of large aperture space telescopes SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE space telescope; segmented optics; mirror; actuators; NGST; ORIGINS AB The hypothesis is tested: space telescopes with apertures larger than a few meters will have lower mass and cost and better optical performance if the primary mirror is aggressively segmented. Optical performance variations are considered from several factors including the gap between regular hexagonal mirror segments, the relative ability of segments of different size to be manufactured with low wavefront error, and expected mirror deformations. A mass variation is derived to relate diameter and thickness of the mirror segments to satisfy mirror deflections and thermally induced stress. Mass estimation includes support structures, actuators, cabling, electronics, hinges, and latches. Cost is evaluated from several models previously proposed to address multiple minor systems. The analyses conclude that there is a relatively-small optimum segment size that is independent of the dimensions of the overall array but which does depend upon the state of technology. It is further shown that a significant mass penalty will be incurred for segments that are either smaller or larger than the optimum size. Minimum mirror thickness is constrained, but engineering design principles for structural deflections and modal frequencies otherwise dictate the design. C1 NASA, George C Marshall Space Flight Ctr, Program Dev, Huntsville, AL 35812 USA. RP Montgomery, EE (reprint author), NASA, George C Marshall Space Flight Ctr, Program Dev, Huntsville, AL 35812 USA. NR 0 TC 2 Z9 2 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 788 EP 798 DI 10.1117/12.324499 PN 1-2 PG 11 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200077 ER PT S AU Smith, AM Pasquale, BA Gong, Q Saif, BN AF Smith, AM Pasquale, BA Gong, Q Saif, BN BE Bely, PY Breckinridge, JB TI Tunable filter for the vacuum ultraviolet SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE filters; ultraviolet filters; tunable filters; imaging monochromator AB Several designs of filters for use in vacuum ultraviolet imaging systems are discussed. These designs incorporate all reflective optics, and are characterized by comparatively high in-band throughput, very low out-of-band transmission and sub-arcsecond spatial resolution. In addition, they can be tuned over ranges useful for vacuum ultraviolet astronomical observations. Results from a simplified laboratory version of the filters intended to prove the concept are presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, AM (reprint author), NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 876 EP 882 DI 10.1117/12.324444 PN 1-2 PG 7 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200086 ER PT S AU Oxnevad, KI AF Oxnevad, KI BE Bely, PY Breckinridge, JB TI A concurrent design approach for designing space telescopes and instruments SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE concurrent engineering; graphical programming; multidisciplinary teams; conceptual design; space telescopes and instruments; total systems approach; systems engineering AB At the Project Design Center at the Jet Propulsion Laboratory, a concurrent design environment is under development for supporting development and analyses of space instruments and telescopes in the early, conceptual design phases. This environment is being utilized by a Team I, a multidisciplinary group of experts. Team I is providing study and proposal support. To provide the required support, the Team I concurrent design environment features effectively interconnected high-end optics, CAD, and thermal design and analysis tools. Innovative approaches for linking tools, and for transferring files between applications have been implemented. These approaches together with effective sharing of geometry between the optics, CAD, and thermal tools are already showing significant timesavings. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Oxnevad, KI (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1027 EP 1035 DI 10.1117/12.324454 PN 1-2 PG 9 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200103 ER PT S AU Morrissey, P Norton, T Kimble, R AF Morrissey, P Norton, T Kimble, R BE Bely, PY Breckinridge, JB TI A photon counting intensified CID detector for space astronomy SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE CID; detector; intensifier; microchannel plates; ultraviolet AB We are developing a novel solar blind, high resolution, photon counting detector for applications in space ultraviolet astronomy. Our concept is to utilize a charge injection device (CID) as the readout stage behind a microchannel plate (MCP) intensifier. This detector will take advantage of the flexible readout options afforded by the addressable CID architecture to provide high local frame rates around bright features in an image. In this concept, the detector bandwidth can be used most efficiently, reading pixels around a bright star more frequently than those in a nearby dim cloud of gas, for example. The demonstration apparatus described in this paper incorporates a 25 mm diameter intensifier tube fiber optically coupled to a commercially available 30 frame-s(-1) 512 x 512 pixel, progressive-scan CID2250 camera (CIDTEC, Inc., Liverpool, NY). The 10 MHz analog video from this camera is digitized and processed by a centroider module that calculates the position of each event in real time with subpixel precision, thus providing high spatial resolution limited by the MCPs. The pore-resolved images presented in this paper validate the intensified CID concept. We plan to incorporate custom driving electronics and an experimental CID with on-chip address decoders for high speed random access of detector subarrays of arbitrary size and location. Our goal is to demonstrate a solar-blind UV photon counter with 200 - 300 counts-s(-1) point source and 3 x 10(5) counts-s(-1) global rate capability with up to 4000 x 4000 elements. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Morrissey, P (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 8 Z9 8 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1036 EP 1045 DI 10.1117/12.324457 PN 1-2 PG 10 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200104 ER PT S AU Shupe, DL Larsen, M Sargent, S Peterson, J Tansock, J Luchik, T Hacking, P Herter, T AF Shupe, DL Larsen, M Sargent, S Peterson, J Tansock, J Luchik, T Hacking, P Herter, T BE Bely, PY Breckinridge, JB TI Estimated performance of the Wide-Field Infrared Explorer (WIRE) instrument SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE cryogenic space telescopes; infrared astronomy; Small Explorer missions; infrared focal plane arrays; pre-flight characterization AB The Wide-Field Infrared Explorer (WIRE) is a small spaceborne cryogenic infrared telescope being readied for launch in September 1998. Part of NASA's Small Explorer program, WIRE will carry out a deep pointed survey in broad 24 and 12 micron passbands designed primarily to study the evolution of starburst galaxies and to search for protogalaxies. The strategy for the WIRE survey and its stare-and-dither technique for building up long exposure times are described. An overview of the WIRE instrument is presented, with emphasis on the results of ground characterization and expected on-orbit performance of the WIRE optics and the Si:As focal plane arrays. The results of the ground characterization demonstrate that WIRE will meet or exceed the requirements for its science objectives. A brief overview is given of the primary and additional science (ranging from the evolution of galaxies to brown dwarf searches to Solar System studies) that will be enabled by WIRE. C1 CALTECH, Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. RP Shupe, DL (reprint author), CALTECH, Jet Prop Lab, IPAC, MS 100-22, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1057 EP 1068 DI 10.1117/12.324463 PN 1-2 PG 12 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200106 ER PT S AU Mosier, G Femiano, M Ha, K Bely, P Burg, R Redding, D Kissil, A Rakoczy, J Craig, L AF Mosier, G Femiano, M Ha, K Bely, P Burg, R Redding, D Kissil, A Rakoczy, J Craig, L BE Bely, PY Breckinridge, JB TI Fine pointing control for a next generation space telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ AB The Next Generation Space Telescope will provide at least ten times the collecting area of the Hubble Space Telescope in a package that fits into the shroud of an expendable launch vehicle. The resulting large, flexible structure provides a challenge to the design of a pointing control system for which the requirements are at the milli-arcsecond level. This paper describes a design concept in which pointing stability is achieved by means of a nested-loop design involving an inertial Attitude Control System (ACS) and a Fast Steering Mirror (FSM). A key to the integrated control design is that the ACS controllers has a bandwidth well below known structural modes and the FSM uses a rotationally balanced mechanism which should not interact with the flexible modes that are within its' control bandwidth. The ACS controller provides stable pointing of the spacecraft bus with star trackers and gyros. This low bandwidth loop (0.025 Hz) uses nearly co-located sensors and actuators to slew and acquire faint guide stars in the NIR camera. This controller provides a payload reference stable to the arcsecond level. Low-frequency pointing errors due to sensor noise and dynamic disturbances are suppressed by a 2-axis gimbaled FSM located in the instrument module. The FSM servo bandwidth of 6 Hz is intended to keep the guide star position stable in the NIR focal plane to the required milli-arcsecond level. The mirror is kept centered in its range of travel by a low-bandwidth loop closed around the ACS. This paper presents the results of parametric trade studies designed to assess the performance of this control design in the presence of modeled reaction wheel disturbances, assumed to be the principle source of vibration for the NGST, and variations in structural dynamics. Additionally, requirements for reaction wheel disturbance levels and potential vibration isolation subsystems were developed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mosier, G (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 4 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1070 EP 1077 DI 10.1117/12.324507 PN 1-2 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200107 ER PT S AU Cheng, ES Smith, RC Jedrich, NM Gibbon, JA Cottingham, DA Swift, WL Dame, RE AF Cheng, ES Smith, RC Jedrich, NM Gibbon, JA Cottingham, DA Swift, WL Dame, RE BE Bely, PY Breckinridge, JB TI The Near Infrared Camera and Multi-Object Spectrometer Cooling System SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE cryocooler; HST AB NASA is developing the NICMOS Cooling System (NCS) for deployment during Servicing Mission 3 (SM3) of the Hubble Space Telescope (HST) in late 1999. The NCS is intended to provide mechanical cryocooling for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument that was installed during Servicing Mission 2 in February 1997. The NICMOS with NCS can potentially continue the near-IR capability of HST through the currently scheduled end-of-mission in 2010. The NCS hardware is currently in final integration and will soon start a series of rigorous ground and flight tests that will prepare it for installation in the HST. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cheng, ES (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 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 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1149 EP 1155 DI 10.1117/12.324515 PN 1-2 PG 7 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200114 ER PT S AU LeBoeuf, CM Davila, PS Redding, DC Morell, A Lowman, AE Wilson, ME Young, EW Pacini, LK Coulter, DR AF LeBoeuf, CM Davila, PS Redding, DC Morell, A Lowman, AE Wilson, ME Young, EW Pacini, LK Coulter, DR BE Bely, PY Breckinridge, JB TI Developmental cryogenic active telescope testbed, a wavefront sensing and control testbed for the next generation space telescope SO SPACE TELESCOPES AND INSTRUMENTS V, PTS 1-2 SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Space Telescopes and Instruments V Conference CY MAR 25-28, 1998 CL KONA, HI SP Int Soc Optical Engn, European So Observ DE NGST; active optics; wavefront sensing wavefront control; segmented optics; hexapod; stewart platforms AB As part of the technology validation strategy of the next generation space telescope (NGST), a system testbed is being developed at GSFC, in partnership with JPL and Marshall Space Flight Center (MSFC), which will include all of the component functions envisioned in an NGST active optical system. The system will include an actively controlled, segmented primary mirror, actively controlled secondary, deformable, and fast steering mirrors, wavefront sensing optics, wavefront control algorithms, a telescope simulator module, and an interferometric wavefront sensor for use in comparing final obtained wavefronts from different tests. The developmental cryogenic active telescope testbed (DCATT) will be implemented in three phases. Phase 1 will focus on operating the testbed at ambient temperature. During Phase 2, a cryocapable segmented telescope will be developed and cooled to cryogenic temperature to investigate the impact on the ability to correct the wavefront and stabilize the image. In Phase 3, it is planned to incorporate industry developed night-like components, such as figure controlled mirror segments, cryogenic, low hold power actuators, or different wavefront sensing and control hardware or software. A very important element of the program is the development and subsequent validation of the integrated multidisciplinary models. The Phase 1 testbed objectives, plans, configuration, and design will be discussed. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP LeBoeuf, CM (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 3 Z9 3 U1 2 U2 5 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2803-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3356 BP 1168 EP 1178 DI 10.1117/12.324517 PN 1-2 PG 11 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL60U UT WOS:000075998200116 ER PT S AU Folta, D Newman, LK Quinn, D AF Folta, D Newman, LK Quinn, D BE Stengle, TH TI Design and implementation of satellite formations and constellations SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The direction to develop small low cost spacecraft has led many scientists to recognize the advantage of flying spacecraft in constellations and formations to achieve the correlated instrument measurements formerly possible only by flying many instruments on a single large platform. Yet, constellations and formation flying impose additional complications on orbit selection and orbit maintenance, especially when each spacecraft has its own orbit or science requirements. The purpose of this paper is to develop an operational control method for maintenance of these missions, Examples will be taken from the Earth Observing-1 (EO-1) spacecraft that is part of the New Millennium Program (NMP) and from proposed Earth System Science Program Office (ESSPO) constellations. Results can be used to determine the appropriateness of constellations and formation flying for a particular case as well as the operational impacts, Applications to the ESSPO and NMP are highly considered in analysis and applications. After constellation and formation analysis is completed, implementation of a maneuver maintenance strategy becomes the driver. Advances in technology and automation by GSFC's Guidance, Navigation, and Control Center allow more of the burden of the orbit selection and maneuver maintenance to be automated and ultimately placed onboard the spacecraft, mitigating most of the associated operational concerns. This paper presents the GSFC closed-loop control method to fly in either constellations or formations through the use of an autonomous closed loop three-axis navigation control and innovative orbit maintenance support. Simulation results using AutoCon(TM) and FreeFlyer(TM) with various fidelity levels of modeling and algorithms are presented. C1 NASA, Goddard Space Flight Ctr, Navigat Guidance & Control Ctr, Syst Engn Branch,Format Flying Technol Lead, Greenbelt, MD 20771 USA. RP Folta, D (reprint author), NASA, Goddard Space Flight Ctr, Navigat Guidance & Control Ctr, Syst Engn Branch,Format Flying Technol Lead, Code 661, Greenbelt, MD 20771 USA. NR 14 TC 6 Z9 8 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 57 EP 70 PN 1&2 PG 6 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700005 ER PT S AU Concha, M DeFazio, R AF Concha, M DeFazio, R BE Stengle, TH TI NanoSat constellation mission design SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The NanoSat constellation concept mission proposes simultaneous operation of multiple swarms of as many as 22 identical 10 kg spacecraft per swarm. The various orbits in a NanoSat swarm vary from 3x12 to 3x42 R-e in geometry. In this report the unique flight dynamics issues of this constellation satellite mission design are addressed. Studies include orbit design, orbit determination, and error analysis. A preliminary survey determined the orbital parameters that would limit the maximum shadow condition while providing adequate ground station access for three ground stations. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Guidance Ctr, Greenbelt, MD 20771 USA. RP Concha, M (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Guidance Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 71 EP 80 PN 1&2 PG 6 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700006 ER PT S AU Newman, LK Hametz, ME Conway, DJ AF Newman, LK Hametz, ME Conway, DJ BE Stengle, TH TI A modernized approach to meet diversified earth observing system (EOS) AM-1 mission requirements SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB From a flight dynamics perspective, the EOS AM-1 mission design and maneuver operations present a number of interesting challenges. The mission design itself is relatively complex for a low Earth mission, requiring a frozen, Sun-synchronous, polar orbit with a repeating ground track, Beyond the need to design an orbit that meets these requirements, the recent focus on low-cost, "lights out" operations has encouraged a shift to more automated ground support. Flight dynamics activities previously performed in special facilities created solely for that purpose and staffed by personnel with years of design experience are now being shifted to the mission operations centers (MOCs) staffed by flight operations team (FOT) operators. These operators' responsibilities include flight dynamics as a small subset of their work; therefore, FOT personnel often do not have the experience to make critical maneuver design decisions. Thus, streamlining the analysis and planning work required for such a complicated orbit design and preparing FOT personnel to take on the routine operation of such a spacecraft both necessitated increasing the automation level of the flight dynamics functionality. The FreeFlyer(TM) software developed by AI Solutions provides a means to achieve both of these goals, The graphic interface enables users to interactively perform analyses that previously required many parametric studies and much data reduction to achieve the same result. In addition, the fuzzy logic engine enables the simultaneous evaluation of multiple conflicting constraints, removing the analyst from the loop and allowing the FOT to perform more of the operations without much background in orbit design. Modernized techniques were implemented for EOS AM-1 flight dynamics support in several areas, including launch window determination, orbit maintenance maneuver control strategies, and maneuver design and calibration automation, The benefits of implementing these techniques include increased fuel available for on-orbit maneuvering, a simplified orbit maintenance process to minimize science data downtime, and an automated routine maneuver planning process. This paper provides an examination of the modernized techniques implemented for EOS AM-1 to achieve these benefits. C1 NASA, Goddard Space Flight Ctr, Navigat Guidance & Control Ctr, Flight Dynam Anal Branch,EOS Flight Dynam Lead AM, Greenbelt, MD 20771 USA. RP Newman, LK (reprint author), NASA, Goddard Space Flight Ctr, Navigat Guidance & Control Ctr, Flight Dynam Anal Branch,EOS Flight Dynam Lead AM, Code 572, Greenbelt, MD 20771 USA. NR 6 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 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 81 EP 95 PN 1&2 PG 7 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700007 ER PT S AU O'Donnell, JR Mangus, DJ AF O'Donnell, JR Mangus, DJ BE Stengle, TH TI An approach to the design and implementation of spacecraft attitude control systems SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB Over 39 years and a long list of missions, the guidance, navigation, and control (GN&C) groups at the Goddard Space Flight Center have gradually developed approaches to the design and implementation of successful spacecraft attitude control systems. With the recent creation of the Guidance, Navigation, and Control Center at Goddard, there is a desire to document some of these design practices to help to ensure their consistent application in the future. In this paper, we will discuss the beginnings of this effort, drawing primarily on the experience of one of the past attitude control system (ACS) groups at Goddard (what was formerly known as Code 712, the Guidance, Navigation, and Control Branch). We will discuss the analysis and design methods and criteria used, including guidelines for linear and nonlinear analysis, as well as the use of low- and high-fidelity simulation for system design and verification of performance. Descriptions of typical ACS sensor and actuator hardware will be shown, and typical sensor/actuator suites for a variety of mission types detailed. A description of the software and hardware test effort will be given, along with an attempt to make some qualitative estimates on how much effort is involved. The spacecraft and GN&C subsystem review cycles will be discussed, giving an outline of what design reviews are typically held and what information should be presented at each stage. Finally, we will point out some of the lessons learned at Goddard. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP O'Donnell, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 572, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 125 EP 139 PN 1&2 PG 5 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700010 ER PT S AU Lozier, D Galal, K Folta, D Beckman, M AF Lozier, D Galal, K Folta, D Beckman, M BE Stengle, TH TI Lunar prospector mission design and trajectory support SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The Lunar Prospector mission is the first dedicated NASA lunar mapping mission since the Apollo Orbiter program which was flown over 25 years ago. Competitively selected under the NASA Discovery Program, Lunar Prospector was launched on January 7, 1998 on the new Lockheed Martin Athena II launch vehicle. The mission design of Lunar Prospector is characterized by a direct minimum energy transfer trajectory to the moon with three scheduled orbit correction maneuvers to remove launch and cislunar injection errors prior to lunar insertion. At lunar encounter, a series of three lunar orbit insertion maneuvers and a small circularization burn were executed to achieve a 100 km altitude polar mapping orbit. This paper will present the design of the Lunar Prospector transfer, lunar insertion and mapping orbits, including maneuver and orbit determination strategies in the context of mission goals and constraints. Contingency plans for handling transfer orbit injection and lunar orbit insertion anomalies are also summarized. Actual flight operations results are discussed and compared to pre-launch support analysis. C1 NASA, Ames Res Ctr, Space Projects Div, Moffett Field, CA 94035 USA. RP Lozier, D (reprint author), NASA, Ames Res Ctr, Space Projects Div, Mail Code 244-14, Moffett Field, CA 94035 USA. NR 7 TC 5 Z9 5 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 297 EP 311 PN 1&2 PG 7 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700022 ER PT S AU Oshman, Y Markley, FL AF Oshman, Y Markley, FL BE Stengle, TH TI Attitude/attitude-rate estimation from GPS differential phase measurements using integrated-rate parameters SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr ID GLOBAL POSITIONING SYSTEM AB A sequential filtering algorithm is presented for attitude and attitude-rate estimation from Global Positioning System (GPS) differential carrier phase measurements. A third-order, minimal-parameter method for solving the attitude matrix kinematic equation is used to parameterize the filter's state, which renders the resulting estimator computationally efficient. Borrowing from tracking theory concepts, the angular acceleration is modeled as an exponentially autocorrelated stochastic process, thus avoiding the use of the uncertain spacecraft dynamic model. The new formulation facilitates the use of aiding vector observations in a unified filtering algorithm, which can enhance the method's robustness and accuracy. Numerical examples are used to demonstrate the performance of the method. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Oshman, Y (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 571, Greenbelt, MD 20771 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 351 EP 365 PN 1&2 PG 7 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700026 ER PT S AU Andrews, SF Morgenstern, WM AF Andrews, SF Morgenstern, WM BE Stengle, TH TI Initial flight results of the TRMM Kalman filter SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The Tropical Rainfall Measuring Mission (TRMM) spacecraft is a nadir pointing spacecraft that nominally controls attitude based on the Earth Sensor Assembly (ESA) output. After a potential single point failure in the ESA was identified, the contingency attitude determination method chosen to backup the ESA-based system was a sixth-order extended Kalman filter that uses magnetometer and digital sun sensor measurements. A brief description of the TRMM Kalman filter will be given, including some implementation issues and algorithm heritage. Operational aspects of the Kalman filter and some failure detection and correction will be described. The Kalman filter was tested in a sun pointing attitude and in a nadir pointing attitude during the in-orbit checkout period, and results from those tests will be presented. This paper will describe some lessons learned from the experience of the TRMM team. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Andrews, SF (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, 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 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 393 EP 406 PN 1&2 PG 6 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700029 ER PT S AU Hartman, KR Gramling, CJ Lee, T Kelbel, DA Long, AC AF Hartman, KR Gramling, CJ Lee, T Kelbel, DA Long, AC BE Stengle, TH TI Relative navigation for spacecraft formation flying SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The Goddard Space Flight Center Guidance, Navigation, and Control Center (GNCC) is currently developing and implementing advanced satellite systems to provide autonomous control of formation flyers. The initial formation maintenance capability will be flight-demonstrated on the EarthOrbiter-1 (EO-1) satellite, which is planned under the National Aeronautics and Space Administration New Millennium Program to be a coflight with the Landsat-7 (L-7) satellite. Formation flying imposes relative navigation accuracy requirements in addition to the orbit accuracy requirements for the individual satellites. In the case of EO-1 and L-7, the two satellites are in nearly coplanar orbits, with a smalt difference in the longitude of the ascending node to compensate for the Earth's rotation, The GNCC has performed trajectory error analysis for the relative navigation of the EO-1/L-7 formation, as well as for a more advanced tracking configuration using crosslink satellite communications. This paper discusses the orbit determination and prediction accuracy achievable for EO-1 and L-7 under various tracking and orbit determination scenarios and discusses the expected relative separation errors in their formation flying configuration. C1 NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Greenbelt, MD 20771 USA. RP Hartman, KR (reprint author), NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Ctr, Code 570, Greenbelt, MD 20771 USA. NR 8 TC 3 Z9 3 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 685 EP 699 PN 1&2 PG 3 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700049 ER PT S AU Deutschmann, J Harman, R Bar-Itzhack, I AF Deutschmann, J Harman, R Bar-Itzhack, I BE Stengle, TH TI A low cost approach to simultaneous orbit, attitude, and rate estimation using an Extended Kalman Filter SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB An innovative approach to autonomous attitude and trajectory estimation is available using only magnetic field data and rate data. The estimation is performed simultaneously using an Extended Kalman Filter, a well known algorithm used extensively in onboard applications. The magnetic field is measured on a satellite by a magnetometer, an inexpensive and reliable sensor flown on virtually all satellites in low earth orbit. Rate data is provided by a gyro, which can be costly. This system has been developed and successfully tested in a post-processing mode using magnetometer and gyro data from 4 satellites supported by the Flight Dynamics Division at Goddard. In order for this system to be truly low cost, an alternative source for rate data must be utilized. An independent system which estimates spacecraft rate has been successfully developed and tested using only magnetometer data or a combination of magnetometer data and sun sensor data, which is less costly than a gyro. This system also uses an Extended Kalman Filter. Merging the two systems will provide an extremely low cost, autonomous approach to attitude and trajectory estimation. In this work we provide the theoretical background of the combined system. The measurement matrix is developed by combining the measurement matrix of the orbit and attitude estimation EKF with the measurement matrix of the rate estimation EKF, which is composed of a pseudo-measurement which makes the effective measurement a function of the angular velocity. Associated with this is the development of the noise covariance matrix associated with the original measurement combined with the new pseudo-measurement. In addition, the combination of the dynamics from the two systems is presented along with preliminary test results. C1 NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Greenbelt, MD 20771 USA. RP Deutschmann, J (reprint author), NASA, Goddard Space Flight Ctr, Flight Dynam Anal Branch, Code 572, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 717 EP 726 PN 1&2 PG 6 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700051 ER PT S AU Ericsson-Jackson, AJ Andrews, SF O'Donnell, JR Markley, FL AF Ericsson-Jackson, AJ Andrews, SF O'Donnell, JR Markley, FL BE Stengle, TH TI Map stability, design and analysis SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The design and analysis of the MAP attitude control system (ACS) have been refined since work previously reported. The full spacecraft and instrument flexible model was developed in NASTRAN, and the resulting flexible modes were plotted and reduced with the Modal Significance Analysis Package (MSAP). The reduced-order model was used to perform the linear stability analysis for each control mode, the results of which are presented in this paper. Although MAP is going to a relatively disturbance-free Lissajous orbit around the Earth-Sun La Lagrange point, a detailed disturbance-torque analysis is required because there are only a small number of opportunities for momentum unloading each year. Environmental torques, including solar pressure at L-2, and aerodynamic and gravity gradient during phasing-loop orbits, were calculated and simulated. A simple model of fuel slosh was derived to model its effect on the motion of the spacecraft. In addition, a thruster mode linear impulse controller was developed to meet the accuracy requirements of the phasing loop burns. A dynamic attitude error limiter was added to improve the performance of the ACS during large attitude slews. The result of this analysis is a stable ACS subsystem that meets all of the mission's requirements. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ericsson-Jackson, AJ (reprint author), NASA, Goddard Space Flight Ctr, Code 570, Greenbelt, MD 20771 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 955 EP 969 PN 1&2 PG 7 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700069 ER PT S AU Bhat, RS Shapiro, BE Frauenholz, RB Leavitt, RK AF Bhat, RS Shapiro, BE Frauenholz, RB Leavitt, RK BE Stengle, TH TI TOPEX/Poseidon orbit maintenance for the first five years SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr ID POSEIDON AB The TOPEX/Poseidon orbit maintenance strategy was changed following launch to include the effects of observed unmodeled, and hence anomalous, along-track accelerations. The anomalous force causes the semi-major axis, a, to either increase (called "boost") or decrease ("deboost" or "decay") depending on the satellite attitude and solar array pitch angle offset. Although this force is the most uncertain parameter in ground track prediction, it has been used as a passive technique for orbit maintenance, thereby reducing the number of propulsive maneuvers, enhancing maneuver spacing, and to place maneuvers at convenient times. This passive technique was first demonstrated in May 1993. The TOPEX/Poseidon orbit has been uniquely maintained using both passive (non-propulsive) and active (propulsive) maneuvers. Furthermore, the orbit has been maintained using only the passive technique since the ninth orbit maintenance maneuver on January 15, 1996. Only nine orbit maintenance maneuvers have been required to maintain the ground track, including verification site over flights, since achieving the operational orbit on September 21, 1992 (mission requirement: 95% within +/- 1 lan). During this period, a has varied within 7714,429 +/- 7 m, while the inclination i periodically fluctuated in the range 66.0408 degrees +/- 0.0040 degrees. The frozen orbit (required e < 0.001 and omega approximate to 90 degrees) has been maintained without any dedicated eccentricity maneuvers. The frozen eccentricity vector has completed two periodic cycles and it is currently tracing its third cycle (period approximate to 26.7 months). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bhat, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 27 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 973 EP 987 PN 1&2 PG 5 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700070 ER PT S AU Esposito, P Alwar, V Demcak, S Graat, E Johnston, M Mase, R AF Esposito, P Alwar, V Demcak, S Graat, E Johnston, M Mase, R BE Stengle, TH TI Mars Global Surveyor navigation and aerobraking at Mars SO SPACEFLIGHT DYNAMICS 1998, VOL 100, PART 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT AAS/GSFC International Symposium on Space Flight Dynamics CY MAY 11-15, 1998 CL GREENBELT, MD SP NASA, Amer Astronaut Soc, Goddard Space Flight Ctr AB The Mars Global Surveyor (MGS) spacecraft was successfully inserted into an elliptical orbit around Mars on 9/12/97, 01:53:49 UTC. This orbit was near polar (inclination=93.26 deg) with an orbital period of 44.993 hours and apoapsis and periapsis altitudes of 54,025.9 lan and 262.9 lan respectively. After a short aerobraking (AB) initiation interval (9/12/97 to 10/2/97), the main phase of AB or orbit period reduction was established. However shortly thereafter, a significant problem with the minus-Y axis solar array developed which necessitated a temporary suspension of AB. Ultimately, this forced the Project to abandon the original plan to complete AB on 1/18/98 and establish the mapping orbit on 3/15/98. The revised plan called for a reduced level of AB, thus subjecting the solar array and yoke assembly to less aerodynamic stress. After 201 orbits and 196 days after MOI, the first phase of AB has ended; the orbital period was 11.64 hours with apoapsis and periapsis altitudes of 17,870.3 and 170.7 km respectively. At present, MGS is in a science phasing orbit (SPO) and shall acquire science data from 3/28/98 to 9/11/98. Thereafter the second phase of AB shall begin and is expected to end during Feb 1999 when the orbital period shall be 1.9 hours and the orbit's descending node shall be at the 2:00 am (local mean solar time) orientation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Esposito, P (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 UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-453-2 J9 ADV ASTRONAUT SCI PY 1998 VL 100 BP 1015 EP 1027 PN 1&2 PG 3 WC Engineering, Aerospace SC Engineering GA BM36J UT WOS:000078498700073 ER PT S AU Guman, MD Roth, DC Williams, BG AF Guman, MD Roth, DC Williams, BG BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Navigation feasibility studies for the Europa Orbiter mission SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB This paper describes preliminary navigation analyses for the proposed Europa Orbiter mission. To quantify achievable navigation accuracies, orbit uncertainties are computed for simulated range and Doppler tracking coverage from NASA's Deep Space Network stations. In addition, single-station optical communication range tracking is simulated to assess its capabilities against those of traditional radiometric tracking. Emphasis is placed on the operations phase of the mission for which additional navigation considerations are investigated; these include spacecraft safety shortly after Europa orbit insertion and sensitivity to various orbit configurations. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Guman, MD (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr,Mail Stop 301-125L, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 161 EP 174 PN 1&2 PG 14 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300009 ER PT S AU Johnston, MD Esposito, PB Alwar, V Demcak, SW Graat, EJ Mase, RA AF Johnston, MD Esposito, PB Alwar, V Demcak, SW Graat, EJ Mase, RA BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Mars Global Surveyor aerobraking at Mars SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB On September 12, 1997, the Mars Global Surveyor (MGS) spacecraft was successfully inserted into a highly elliptical capture orbit about Mars. To establish the required mapping orbit, the MGS spacecraft must supplement its propulsive capabilities by aerobraking. This paper describes the aerobraking strategy developed for the MGS mission. This description includes the aerobraking constraints imposed on the trajectory design, the approach toward aerobraking trajectory control, and the aerobraking flight profile that resulted from the planning activities that occurred after launch. The initial aerobraking results are contrasted to the planned baseline trajectory. Additionally, this paper describes the aerobraking progress of the MGS spacecraft made following a three week aerobraking hiatus that occurred in October 1997. This hiatus was initiated in order to provide time to evaluate the viability of continuing aerobraking with newly discovered damage to one of the two spacecraft's solar arrays. The results of the stand-down forced a major re evaluation of the MGS mission and this paper briefly describes the new mission outlook. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnston, MD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 264-235, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 3 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 205 EP 223 PN 1&2 PG 19 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300012 ER PT S AU Lo, MW Ross, SD AF Lo, MW Ross, SD BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Low energy interplanetary transfers using the invariant manifolds of L1, L2, and halo orbits SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The Lagrange points LI and L2 have associated with them so-called stable and unstable manifolds. These trajectories are extremely large global objects in phase space which for the outer planets form a network of intersecting dynamical channels. This gravitational network contributes to many long-standing phenomena in the dynamics of the Solar System. The temporary capture of Jupiter comets is explained by the behavior of the manifolds of Jupiter's L1 and L2. These dynamical phenomena maybe exploited for space missions to obtain low energy interplanetary transfers and ballistic capture orbits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lo, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-142, Pasadena, CA 91109 USA. RI Ross, Shane/B-7237-2009 OI Ross, Shane/0000-0001-5523-2376 NR 0 TC 3 Z9 4 U1 1 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 551 EP 561 PN 1&2 PG 11 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300033 ER PT S AU Smith, RH AF Smith, RH BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI An analysis of shuttle-based performance of MEMS sensors SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The use of micro/nanotechnology (MNT) devices in space applications has the potential of revolutionizing some basic spacecraft subsystems. Their low cost, weight and volume, and mass producibility make them ideal for an era of spaceflight that concentrates on smaller and less expensive spacecraft. This paper introduces the reader to a Shuttle based testbed program and some of its basic objectives. One of the core demonstrations of the STS-93 flight of the testbed will involve a suite of microaccelerometers and gyros. A pre-flight prediction of their performance will be given. Furthermore, a review of their basic operating features and potential applications will also be presented. C1 NASA, Johnson Space Ctr Off, Houston, TX 77058 USA. RP Smith, RH (reprint author), NASA, Johnson Space Ctr Off, 2101 NASA Rd,Suite 609, Houston, TX 77058 USA. NR 0 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 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 629 EP 639 PN 1&2 PG 11 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300039 ER PT S AU Vaughan, RM Kallemeyn, PH Spencer, DA Braun, RD AF Vaughan, RM Kallemeyn, PH Spencer, DA Braun, RD BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Navigation flight operations for Mars Pathfinder SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB On July 4, 1997, Mars Pathfinder became the first spacecraft to land on the surface of Mars in 21 years. Pathfinder was launched on December 4, 1996 and spent seven months en route to the red planet. This paper discusses the navigation flight experience for the Mars Pathfinder interplanetary cruise. In particular, orbit determination and maneuver design and execution results are presented. Special emphasis is given to the navigation role in the days and hours leading up to and including the Entry, Descent, and Landing (EDL) phase. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Vaughan, RM (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr,MS 179-220 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 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 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 643 EP 662 PN 1&2 PG 20 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300040 ER PT S AU Spencer, DA Blanchard, RC Thurman, SW Braun, RD Peng, CY Kallemeyn, PH AF Spencer, DA Blanchard, RC Thurman, SW Braun, RD Peng, CY Kallemeyn, PH BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Mars Pathfinder atmospheric entry reconstruction SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The primary objective of the Mars Pathfinder mission was to demonstrate an innovative, low-cost and reliable method for placing a science payload on the surface of Mars, This paper describes the results of an effort to assess the spacecraft performance during Entry, Descent and Landing. Analysis of the raw accelerometer and altimeter flight data obtained by the Pathfinder spacecraft during atmospheric Right is provided. Results of an effort to reconstruct the spacecraft trajectory are presented. Preliminary findings of the multibody dynamics during terminal descent are described. An estimate of the Mars atmosphere profile encountered during atmospheric flight is given. C1 CALTECH, Jet Prop Lab, Mars Program Off, Pasadena, CA 91109 USA. RP Spencer, DA (reprint author), CALTECH, Jet Prop Lab, Mars Program Off, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 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 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 663 EP 692 PN 1&2 PG 30 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300041 ER PT S AU Salama, AH Kennedy, BM AF Salama, AH Kennedy, BM BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Topex/poseidon "quick-look" precision orbit determination improvement and performance SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The Topex/Poseidon satellite, launched on 10 August 1992, is now in its sixth, year of operations and third year of extended mission. The last couple of years have been characterized by a flight team operating with minimal resources, two major satellite anomalies, reduction in Satellite Laser Ranging (SLR) tracking data, and some Global Positioning System Development Receiver (GPSDR) problems. Despite these shortcomings, the Precision orbit determination and Verification Team (PVT) has improved the processing of its Medium precision Orbit Ephemerides (MOE). The MOEs are now provided to the science community 3 days after-the-track instead of the 4-day baseline without loss of precision. Comparison between the previous 4-day processing and the approved 3-day delivery is presented in the paper. It, also, presents a performance summary of the "quick-look" orbit determination using GPS and SLR tracking data since the beginning of the extended mission. The main feature of this process is that MOE orbits are produced with small radial position error (<5 cm RMS), on a short prediction schedule (3 days). The quick-look orbits are used in support of the Interim Geophysical Data Record (IGDR) production. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Salama, AH (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 805 EP 813 PN 1&2 PG 9 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300050 ER PT S AU Evans, SW AF Evans, SW BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Eclipses by the earth and by the moon as constraints on the AXAF mission SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The Advanced X-ray Astrophysics Facility (AXAF) is scheduled for launch in late 1998, on a mission lasting ten years. During this time AXAF will be subject to eclipses by the Earth and the Moon. Eclipses by the Earth will occur during regular "seasons" six months apart. AXAF requires that none of these last longer than 120 minutes, and this requirement constrains the orbit orientation. Eclipses by the Moon occur infrequently, but may pose serious operational problems. Once the other initial conditions are known,the AXAF perigee altitude can be chosen so that objectionable Moon-eclipses can be avoided. C1 NASA, George C Marshall Space Flight Ctr, Orbital Mech & Navigat Team, Marshall Space Flight Ct, AL 35812 USA. RP Evans, SW (reprint author), NASA, George C Marshall Space Flight Ctr, Orbital Mech & Navigat Team, Mail Code ED13, Marshall Space Flight Ct, AL 35812 USA. NR 0 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 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 989 EP 1000 PN 1&2 PG 12 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300061 ER PT S AU Tan-Wang, GH Sims, JA AF Tan-Wang, GH Sims, JA BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Mission design for the Deep Space 4/Champollion comet sample return mission SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB The Deep Space 4/Champollion mission will be the first to land a spacecraft on the surface of a comet, perform in-situ science, and collect a subsurface sample which it will return to Earth for analysis. This paper describes the trade studies resulting in the current reference mission, which uses solar electric propulsion to rendezvous with the comet Tempel 1 in December 2005 after launching In April 2003. An option which-uses a chemical propulsion system to return to Earth is discussed. C1 CALTECH, Jet Prop Lab, Mission & Syst Architecture Sect, Pasadena, CA 91109 USA. RP Tan-Wang, GH (reprint author), CALTECH, Jet Prop Lab, Mission & Syst Architecture Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 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 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 1205 EP 1212 PN 1&2 PG 8 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300075 ER PT S AU Bhaskaran, S Desai, SD Dumont, PJ Kennedy, BM Null, GW Owen, WM Riedel, JE Synnott, SP Werner, RA AF Bhaskaran, S Desai, SD Dumont, PJ Kennedy, BM Null, GW Owen, WM Riedel, JE Synnott, SP Werner, RA BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Orbit determination performance evaluation of the Deep Space 1 autonomous navigation system SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB NASA's New Millennium Program consists of a series of missions whose primary purpose is to demonstrate the feasibility of new technologies for spaceflight. Deep Space I, the first mission in the New Millennium Program, will demonstrate an Ion propulsion System to provide thrust and;an autonomous onboard navigation system to guide the spacecraft. The mission plan is to fly by an asteroid, Mars, and a comet using these and other new technologies. The onboard navigation system, in order to be as self-contained as possible, uses images of asteroids taken by the spacecraft's camera as its sole data type in determining the spacecraft's trajectory. These images are clustered at intervals varying from hours to a week depending on the phase of the mission, with up to 12 different asteroids sighted per cluster. The images are then incorporated into a least-squares filter at periodic intervals to estimate spacecraft orbit parameters. The orbit determination solutions are in turn used by the navigation system to compute maneuvers required to guide the spacecraft to its targets. Since this navigation strategy has never before been used in flight, it is important to perform pre-launch assessments of its performance. This is accomplished by the use of Monte Carlo simulations which drive the navigation software with a truth model of the spacecraft trajectory and the observables. The truth model simulates realistic errors which are expected in flight, and individual realizations of these errors are drawn from random samplings of the errors with provided statistics. This technique is used to analyze the first leg of the mission, the flyby of the asteroid McAuliffe. The results indicate that, under nominal conditions, the combined orbit determination/maneuver computation strategy is capable of navigating the spacecraft to a safe flyby. In addition, the propulsive events required are within the abilities of the hardware. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Bhaskaran, S (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 5 Z9 5 U1 0 U2 1 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 1295 EP 1314 PN 1&2 PG 20 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300080 ER PT S AU Wolff, PJ Pinto, F Williams, BG Vaughan, RM AF Wolff, PJ Pinto, F Williams, BG Vaughan, RM BE Middour, JW Sackett, LL DAmario, LA Byrnes, DV TI Navigation considerations for low-thrust planetary missions SO SPACEFLIGHT MECHANICS 1998, VOL 99, PTS 1 AND 2 SE ADVANCES IN THE ASTRONAUTICAL SCIENCES LA English DT Proceedings Paper CT 8th Annual Space Flight Mechanics Meeting CY FEB 09-11, 1998 CL MONTEREY, CA SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut, AAS, Space Flight Mech Tech Comm, AIAA, Astrodynam Tech Comm AB Motivated by the upcoming launch of the solar electric propulsion mission New Millennium Deep Space I, an analysis of the operational navigation strategies affecting ground based, deep space orbit determination of low-thrust missions is addressed. Simulations are performed to assess strategies for radiometric based calibration of the SEP engine. Covariance analysis studies are conducted for a spectrum of low-thrust mission phases including deep space cruise, small body flyby, and small body rendezvous. Orbit determination strategies for coping with a spacecraft whose dynamics are corrupted by relatively large, long term stochastic perturbations are assessed. Sensitivities of navigation accuracy to variations in data scheduling, observation data noise, and stochastic parameter mismodeling are compared. C1 CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, Pasadena, CA 91109 USA. RP Wolff, PJ (reprint author), CALTECH, Jet Prop Lab, Navigat & Flight Mech Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 2 U1 0 U2 0 PU UNIVELT INC PI SAN DIEGO PA PO BOX 28130, SAN DIEGO, CA 92128 USA SN 1081-6003 BN 0-87703-450-8 J9 ADV ASTRONAUT SCI PY 1998 VL 99 BP 1425 EP 1438 PN 1&2 PG 14 WC Engineering, Aerospace SC Engineering GA BL82A UT WOS:000076812300088 ER PT S AU Wang, Y Russell, SD Shimabukuro, RL AF Wang, Y Russell, SD Shimabukuro, RL BE Sutherland, RL TI Electronically tunable mirror with surface plasmons SO SPATIAL LIGHT MODULATORS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Spatial Light Modulators CY JAN 28-29, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE electro-optics; tunable mirror; surface plasmon; light modulator AB Surface plasmon tunable filter is a new technology under development at the Jet Propulsion Laboratory. This technology can also be used to build an electronically tunable mirror. When white light is incident on a metal/electro-optic material interface under certain conditions, surface plasmon waves can be excited at the interface. Photons in the wavelength range of the surface plasmon resonance will be converted into the energy of free electrons in the metal. When using nickel or a rhodium/aluminum bilayer as the metal, the bandwidth of the surface plasmon resonance can cover all of the visible spectrum. This surface plasmon resonance depends on the dielectric constants of both the metal and the electro-optic material. Therefore, application of a voltage to the electro optic material to change its dielectric constant can theoretically result in a change in the reflectivity of the interface from less than 0.5% to over 80%. The experimental results show a contrast ratio of 50:1 and a maximum reflection of 50%. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 2 Z9 2 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 0-8194-2731-4 J9 P SOC PHOTO-OPT INS PY 1998 VL 3292 BP 103 EP 106 DI 10.1117/12.305495 PG 4 WC Optics SC Optics GA BL04N UT WOS:000074113100011 ER PT B AU Schieldge, JP Kahle, A AF Schieldge, JP Kahle, A GP AMS AMS TI Use of remotely sensed and in situ data to investigate the effects of surface heterogeneity and terrain on the spatial and temporal distribution of sensible and latent heat fluxes in the semi-arid San Pedro Basin SO SPECIAL SYMPOSIUM ON HYDROLOGY LA English DT Proceedings Paper CT Special Symposium on Hydrology CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc (AMS) C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schieldge, JP (reprint author), CALTECH, Jet Prop Lab, MS 183-501, Pasadena, CA 91109 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 1998 BP 61 EP 62 PG 2 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA BM02P UT WOS:000077436500014 ER PT B AU Houser, PR Harlow, C Shuttleworth, WJ Keefer, TO Emmerich, WE Goodrich, DC AF Houser, PR Harlow, C Shuttleworth, WJ Keefer, TO Emmerich, WE Goodrich, DC GP AMS AMS TI Evaluation of multiple flux measurement techniques using water balance information at a semi-arid site SO SPECIAL SYMPOSIUM ON HYDROLOGY LA English DT Proceedings Paper CT Special Symposium on Hydrology CY JAN 11-16, 1998 CL PHOENIX, AZ SP Amer Meteorol Soc (AMS) AB A month-long field experiment was performed at the Lucky Hills Metflux site in the Walnut Gulch Experimental Watershed during the 1996 summer rainy season to evaluate multiple surface water and energy flux measurement techniques using detailed water balance information. Five different surface flux instruments were deployed between July 14 and August 21, 1996. These instruments included a propeller eddy covariance system, a sonic anemometer and infrared gas analyzer based eddy covariance system. a infrared gas analyzer based Bowen ratio system, and two temperature variance systems. The water balance was computed using precipitation measured in 7 nearby rain gauges, flume measured subcatchment runoff, and root zone soil moisture measured using Time-Domain Reflectometry (TDR). Based on the water balance, most of the surface water and energy flux measurement instruments overestimated the evapotranspiration, and there was significant inter-instrument variation. Some of the observed differences may be due to fetch heterogeneity or instrument limitations, however there may also be issues regarding the application of these instruments and their associated measurement theory in this environment. C1 Univ Arizona, Tucson, AZ USA. RP Houser, PR (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RI Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 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 1998 BP 84 EP 87 PG 4 WC Meteorology & Atmospheric Sciences; Oceanography; Water Resources SC Meteorology & Atmospheric Sciences; Oceanography; Water Resources GA BM02P UT WOS:000077436500020 ER PT B AU Leisawitz, D Digel, SW Guo, Z Mendez, B Hanson, MM AF Leisawitz, D Digel, SW Guo, Z Mendez, B Hanson, MM BE Yun, JL Liseau, R TI A study of the infrared spectral energy distributions of HII regions SO STAR FORMATION WITH INFRARED SPACE OBSERVATORY (ISO) SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Star Formation with the Infrared Space Observatory CY JUN 24-26, 1997 CL LISBON, PORTUGAL SP Univ Lisbon, Res Grp Astron & Astrophys, JNICT, Gulbenkian Fdn, Fundacao Fac Ciencias Univ Lisboa AB Infrared spectral energy distributions (SEDs) of several isolated star-forming regions were derived from observations made by the Diffuse Infrared Background Experiment (DIRBE) on NASA's Cosmic Background Explorer (COBE). Recently obtained near-IR photometric observations of five regions will be used in conjunction with 2 mu m spectroscopy to locate and classify visually obscured O and early-B stars. Our objective is to learn in some detail how the stellar population and the local interstellar environment affect the IR SED. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Leisawitz, D (reprint author), NASA, Goddard Space Flight Ctr, Code 631, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-52-X J9 ASTR SOC P PY 1998 VL 132 BP 101 EP 106 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BK81Z UT WOS:000073480900014 ER PT B AU Tatischeff, V Ramaty, R Kozlovsky, B AF Tatischeff, V Ramaty, R Kozlovsky, B BE Mezzacappa, A TI X-rays from accelerated ion interactions in Orion SO STELLAR EVOLUTION, STELLAR EXPLOSIONS AND GALACTIC CHEMICAL EVOLUTION LA English DT Proceedings Paper CT 2nd Oak Ridge Symposium on Atomic and Nuclear Astrophysics CY DEC 02-06, 1997 CL OAK RIDGE, TN AB We have developed in detail the theory of X-ray line and continuum production due to atomic interactions of accelerated ions. We applied our calculations to the Orion region from which nuclear gamma-ray lines were observed with the COMPTEL instrument on CGRO. We predict strong line emission in the range from 0.5 to 1 keV, mainly due to de-excitations in fast O ions. Much of the diffuse X-ray emission observed with ROSAT from Orion could be due to accelerated ions. If future observations with high spectral resolution would confirm the predicted X-rays, the combined analysis of the X-ray and gamma-ray data will set important constraints on the origin of the accelerated particles and their interaction model. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Tatischeff, V (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0555-X PY 1998 BP 185 EP 189 PG 5 WC Astronomy & Astrophysics; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Astronomy & Astrophysics; Physics GA BL90Y UT WOS:000077110500023 ER PT B AU Kallman, T AF Kallman, T BE Mezzacappa, A TI The X-ray absorption spectra of AGNs SO STELLAR EVOLUTION, STELLAR EXPLOSIONS AND GALACTIC CHEMICAL EVOLUTION LA English DT Proceedings Paper CT 2nd Oak Ridge Symposium on Atomic and Nuclear Astrophysics CY DEC 02-06, 1997 CL OAK RIDGE, TN AB X-ray absorption provides important clues to the origins of the gas flows in active galaxies and quasars (AGN). Both observational and theoretical evidence suggests that a large fraction of the gas in these objects is highly ionized, and therefore best observed in X-rays. Current X-ray spectral observations constrain the degree of ionization of this gas. I will present a summary of these results, together with a discussion of models for the spectra and predictions for future observations. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Kallman, T (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0555-X PY 1998 BP 233 EP 242 PG 10 WC Astronomy & Astrophysics; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Astronomy & Astrophysics; Physics GA BL90Y UT WOS:000077110500028 ER PT B AU Bhatia, AK Kastner, SO AF Bhatia, AK Kastner, SO BE Mezzacappa, A TI Optical depths and escape probabilities from observed line widths and intensities SO STELLAR EVOLUTION, STELLAR EXPLOSIONS AND GALACTIC CHEMICAL EVOLUTION LA English DT Proceedings Paper CT 2nd Oak Ridge Symposium on Atomic and Nuclear Astrophysics CY DEC 02-06, 1997 CL OAK RIDGE, TN AB Many observed solar emission lines suffer resonance scattering. This has not been taken into account in most observers' analyses of line intensity, which assume optically thin condition. Consequently, this contributes to discrepancies between properties inferred from various lines. A method is described which can potentially obtain optical thicknesses and associated quantities from measured intensities and line widths, making use of convenient expressions for photon escape probabilities and for opacity-broadened halfwidths of (non-Gaussian profile) lines scattered according to Doppler (Gaussian) profiles. With this method the effects of opacity on Si II spectral lines are examined using lines observed in a solar prominence. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND BN 0-7503-0555-X PY 1998 BP 291 EP 295 PG 5 WC Astronomy & Astrophysics; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Astronomy & Astrophysics; Physics GA BL90Y UT WOS:000077110500035 ER PT B AU Lou, MC AF Lou, MC BE Shiraishi, N Shinozuka, M Wen, YK TI Implementation of fracture control for structural safety of space flight systems SO STRUCTURAL SAFETY AND RELIABILITY, VOLS. 1-3 LA English DT Proceedings Paper CT 7th International Conference on Structural Safety and Reliability (ICOSSAR 97) CY NOV 24-28, 1997 CL INT ASSOC STRUCT SAFETY & RELIABIL, KYOTO, JAPAN SP Amer Assoc Wind Engn, Amer Concrete Inst, Amer Soc Civil Engn, Int Assoc Earthquake Engn, Int Assoc Struct Mech Reactor Technol, Int Assoc Wind Engn, Reun Int Lab Essai & Rech Mat & Construct, Architectural Inst Japan, Japan Assoc Wind Engn, Japan Concrete Inst, Japan Soc Aeronaut & Space Sci, Japan Soc Civil Engn, Japan Soc Mech Engn, Japan Soc Seism Isolat, Japan Struct Consultants Assoc, Japan Welding Soc, Japan Inst Syst Res, Japanese Geotech Soc, Marine & Fire Insurance Assoc Japan Inc, Sci Council Japan, Liaison Comm Safety Engn, Liaison Comm Struct Engn, Soc Mat Sci Japan, Soc Naval Architects Japan, Soc Steel Construct Japan HO INT ASSOC STRUCT SAFETY & RELIABIL AB Implementation of fracture control for payload structures of NASA manned space night systems has contributed significantly tb the safe operations of the Space Shuttle. An overview of Shuttle payload fracture control program is presented to address the basic assumptions and limitations,, procedures for the identification of fracture-critical components, containment and safe-life verification methodologies, capabilities of non-destructive examination inspections, proof test logic,;and treatment of inherently safety-critical structural elements. Selected lessons learned from the implementation experience of Shuttle payload fracture control dyer the past sixteen years are also discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lou, MC (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 A A BALKEMA PUBLISHERS PI LEIDEN PA SCHIPHOLWEG 107C, PO BOX 447, 2316 XC LEIDEN, NETHERLANDS BN 90-5410-978-5 PY 1998 BP 1195 EP 1202 PG 8 WC Engineering, Civil; Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA BM39Q UT WOS:000078605500165 ER PT J AU DeLand, MT Cebula, RP AF DeLand, MT Cebula, RP TI SSBUV and NOAA-11 SBUV/2 solar variability measurements SO STUDIA GEOPHYSICA ET GEODAETICA LA English DT Article DE solar UV irradiance; solar cycle; solar irradiance variations ID IRRADIANCE AB The Shuttle SBUV (SSBUV) and NOAA-11 SBUV/2 instruments measured solar spectral UV irradiance during the maximum and declining phase of solar cycle 22. The SSBUV data accurately represent the absolute solar UV irradiance between 200-405 nm, and also show the long-term variations during eight flights between October 1989 and January 1996. These data have been used to correct long-term sensitivity changes in the NOAA-11 and SBUV/2 data, which provide a near-daily record of solar UV variations over the 170-400 nm region between December 1988 and October 1994. The NOAA-11 data demonstrate the evolution of short-term solar UV activity during solar cycle 22. C1 Raytheon STX Corp, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DeLand, MT (reprint author), Raytheon STX Corp, 4400 Forbes Blvd, Lanham, MD 20706 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0039-3169 J9 STUD GEOPHYS GEOD JI Stud. Geophys. Geod. PY 1998 VL 42 IS 2 BP 83 EP 91 DI 10.1023/A:1023350017847 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 127PU UT WOS:000076360400001 ER PT B AU Rutledge, SK Banks, BA AF Rutledge, SK Banks, BA BE Sudarshan, TS Jeandin, M Khor, KA TI Atomic oxygen texturing of polymers and carbons SO SURFACE MODIFICATION TECHNOLOGIES XI LA English DT Proceedings Paper CT 11th International Conference on Surface Modification Technologies CY SEP 08-10, 1997 CL PARIS, FRANCE SP Soc Francaise Met & Materiaux, Federat European Mat Soc, Inst Mat, London, Minerals, Met & Mat Soc, ASM Int AB Atomic oxygen, which is present in the low Earth orbit environment of space, can be used to texture the surface of polymers and some forms of carbon. It can be produced in vacuum chambers in the form of a plasma or directed beam using high voltage, radio frequency or microwave dissociation of oxygen gas. The textures that are produced are typically five microns in height or less. These textures can allow alteration of the surface properties without affecting the bulk material. Surfaces textured in this manner can experience increased or decreased static coefficient of friction, reduced water contact angle, increased diffuse transmittance and increased radiant heat transfer capability. These properties are of value for a variety of applications such as broad illumination fibre optics and as a replacement for chemical treatments to make polymers less sticky to the touch. This paper discusses the effects of various levels of atomic oxygen treatment on the transmittance, static coefficient of friction, and water contact angle for acrylic and compares the latter two with some previously measured data for other polymers and carbon. Changes in radiant heat transfer for carbon-carbon composites are also discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44138 USA. RP Rutledge, SK (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd,MS 309-2, Cleveland, OH 44138 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON SW1Y 5DB, ENGLAND BN 1-86125-055-X PY 1998 BP 348 EP 356 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BN40T UT WOS:000081833400040 ER PT B AU Banks, BA Rutledge, SK Snyder, SA AF Banks, BA Rutledge, SK Snyder, SA BE Sudarshan, TS Jeandin, M Khor, KA TI Electric arc and electrochemical surface texturing technologies SO SURFACE MODIFICATION TECHNOLOGIES XI LA English DT Proceedings Paper CT 11th International Conference on Surface Modification Technologies CY SEP 08-10, 1997 CL PARIS, FRANCE SP Soc Francaise Met & Materiaux, Federat European Mat Soc, Inst Mat, London, Minerals, Met & Mat Soc, ASM Int AB Surface texturing of conductive materials can readily be accomplished by means of a moving electric are which produces a plasma from the environmental gases as well as from the vaporized substrate and are electrode materials. As the arc is forced to move across the substrate surface, a condensate from the plasma re-deposits an extremely rough surface which is intimately mixed and attached to the substrate material. The are textured surfaces produce greatly enhanced thermal emittance and hold potential for use as high temperature radiator surfaces in space, as well as in systems which use radiative heat dissipation such as Computer Assisted Tomography (CAT) scan systems. Electrochemical texturing of titanium alloys can be accomplished by using sodium chloride solutions along with ultrasonic agitation to produce a random distribution of craters on the surface. The crater size and density can be controlled to produce surface craters appropriately sized for direct bone ingrowth of orthopaedic implants. Electric are texturing and electrochemical texturing techniques, surface properties and potential applications will be presented. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Banks, BA (reprint author), NASA, Lewis Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU INST MATERIALS PI LONDON PA 1 CARLTON HOUSE TERRACE, LONDON SW1Y 5DB, ENGLAND BN 1-86125-055-X PY 1998 BP 397 EP 402 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA BN40T UT WOS:000081833400045 ER PT S AU Lakshmi, V Susskind, J Choudhury, BJ AF Lakshmi, V Susskind, J Choudhury, BJ BE Choudhury, BJ Tanaka, S Kondo, A Menenti, M Becker, F TI Determination of land surface skin temperatures and surface air temperature and humidity from TOVS HIRS2/MSU data SO SYNERGISTIC USE OF MULTISENSOR DATA FOR LAND PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A3 1 Symposium of COSPAR Scientific Commission A on Synergistic Use of Multisensor Data for Land Processes at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astronaut Federat, NOAA, Natl Environm Satellite, Data & Informat Serv, Int Union Geodesy & Geophys, Int Assoc Hydrol Sci, European Space Agcy, Sci Comm Ocean Res, World Climate Res Programme, UN Off Outer Space Affairs ID CLIMATE MODEL; UNITED-STATES; SOIL-MOISTURE; RANGE; PRECIPITATION; VARIABILITY; PARAMETERS; CANADA AB Global climate models operate at scales that are compatible with satellite observations of the earth surface. It is very useful to use retrieved satellite data for the purposes of comparisons with models for validation and calibration. The objective of this paper is to demonstrate that the TOVS Pathfinder Path A data set is useful for the study of land surface process/dynamics for contrasting climatic regions and the relationships between different surface variables. The results show that the anomalies of the diurnal difference of surface skin temperature are related to the anomalies of the monthly precipitation with increasing precipitation anomalies corresponding with decreasing diurnal skin surface temperature difference anomalies. This follows our understanding that increased surface wetness leads to increased evapotranspiration and reduced diurnal (pm minus am) surface skin temperature differences. (C) 1998 COSPAR. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Gen Sci Corp, Atmospheres Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Lakshmi, V (reprint author), NASA, Goddard Space Flight Ctr, Gen Sci Corp, Atmospheres Lab, Code 910-4, Greenbelt, MD 20771 USA. RI Lakshmi, Venkat/I-3078-2016 OI Lakshmi, Venkat/0000-0001-7431-9004 NR 12 TC 14 Z9 14 U1 0 U2 4 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043469-X J9 ADV SPACE RES PY 1998 VL 22 IS 5 BP 629 EP 636 DI 10.1016/S0273-1177(97)01123-X PG 8 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BL67V UT WOS:000076297800003 ER PT S AU Choudhury, BJ AF Choudhury, BJ BE Choudhury, BJ Tanaka, S Kondo, A Menenti, M Becker, F TI Estimation of vapor pressure deficit over land surfaces from satellite observations SO SYNERGISTIC USE OF MULTISENSOR DATA FOR LAND PROCESSES SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT A3 1 Symposium of COSPAR Scientific Commission A on Synergistic Use of Multisensor Data for Land Processes at 31st COSPAR Scientific Assembly CY JUL 14-21, 1996 CL BIRMINGHAM, ENGLAND SP Comm Space Res, Int Astronaut Federat, NOAA, Natl Environm Satellite, Data & Informat Serv, Int Union Geodesy & Geophys, Int Assoc Hydrol Sci, European Space Agcy, Sci Comm Ocean Res, World Climate Res Programme, UN Off Outer Space Affairs AB Vapor pressure deficit over the land surface is needed in physically based calculations of evaporation and for estimating the efficiency of water utilization to perform photosynthesis by terrestrial plant communities. The two primary data required for this variable, namely air temperature and vapor pressure (or humidity), are currently available at isolated locations. Spatially representative global data of observed vapor pressure deficit are not currently available. This paper presents an approach for estimating monthly mean deficit from satellite observations and then evaluates the accuracy of the estimated values through comparison with globally distributed surface measurements, The standard error of estimate was found to be 4 hPa. Published by Elsevier Science Ltd on behalf of COSPAR. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Choudhury, BJ (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NR 5 TC 7 Z9 8 U1 0 U2 3 PU PERGAMON PRESS LTD PI OXFORD PA THE BOULEVARD LANGFORD LANE KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0273-1177 BN 0-08-043469-X J9 ADV SPACE RES PY 1998 VL 22 IS 5 BP 669 EP 672 DI 10.1016/S0273-1177(97)01128-9 PG 4 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Remote Sensing SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences; Remote Sensing GA BL67V UT WOS:000076297800008 ER PT B AU Hathaway, DH AF Hathaway, DH BE Balasubramaniam, KS Harvey, JW Rabin, DM TI Synoptic datasets and solar activity predictions SO SYNOPTIC SOLAR PHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 18th National-Solar-Observatory/Sacramento-Peak Summer Workshop on Synoptic Solar Physics CY SEP 08-12, 1997 CL SUNSPOT, NM SP Natl Solar Observ, Natl Optical Astron Observ, Natl Sci Fdn, Div Atmospher Sci, NASA, Space Sci Div, Off Space Sci, USAF, Off Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev, USAF, Air Force Res Lab, Space Hazards Branch AB Synoptic datasets are crucial to our understanding and prediction of the solar activity cycle. These datasets provide information on both the characteristics of the activity cycle and its current condition. I review some of the solar cycle characteristics gleaned from these datasets and indicate how current observations of the magnetic and Doppler velocity fields might allow for more accurate and physically meaningful predictions. I suggest that the key to such predictions is the detection, characterization, and continuous observation of the giant cell convective motions. C1 NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Hathaway, DH (reprint author), NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 0 TC 7 Z9 7 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-60-0 J9 ASTR SOC P PY 1998 VL 140 BP 47 EP 55 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74T UT WOS:000076547800004 ER PT B AU Jones, HP AF Jones, HP BE Balasubramaniam, KS Harvey, JW Rabin, DM TI Histograms of synoptic spectromagnetograph observations SO SYNOPTIC SOLAR PHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 18th National-Solar-Observatory/Sacramento-Peak Summer Workshop on Synoptic Solar Physics CY SEP 08-12, 1997 CL SUNSPOT, NM SP Natl Solar Observ, Natl Optical Astron Observ, Natl Sci Fdn, Div Atmospher Sci, NASA, Space Sci Div, Off Space Sci, USAF, Off Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev, USAF, Air Force Res Lab, Space Hazards Branch AB Specialized histograms are computed from the five-dimensional (magnetic, velocity, intensity, equivalent width, line depth), daily full-disk magnetograms obtained with the NASA/National Solar Observatory(1) (NSO) Spectromagnetograph (SPM) at the Kitt Peak Vacuum Telescope (KPVT) as part of a systematic effort to clean and archive the data. This study examines the internal correlations between the observed SPM variables using histograms summed both by Carrington rotation and over the nearly two years of data which have been compared previously with spacecraft observations of total solar irradiance. A preliminary inference from these data is that the structure of the SPM intercorrelations has little relation to solar irradiance variations. For example, strongly unipolar regions and mixed polarity magnetic regions account for important and approximately equal variance in the SPM data, while only the former correlate well with solar irradiance. Yet the internal relationships within the SPM observed quantities for these features are not strongly different. On the other hand, the internal correlations for equivalent width and line depth in sunspot penumbrae are quite different from umbrae or other magnetic regions. Yet both umbrae and penumbrae have statistically similar variations over time and, as a single classification, account for a major portion of both SPM and total irradiance variance. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, SW Solar Stn, Tucson, AZ 85726 USA. RP Jones, HP (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, SW Solar Stn, C-o NSO,POB 26732, Tucson, AZ 85726 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-60-0 J9 ASTR SOC P PY 1998 VL 140 BP 145 EP 153 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74T UT WOS:000076547800014 ER PT B AU Ruzmaikin, A Feynman, J AF Ruzmaikin, A Feynman, J BE Balasubramaniam, KS Harvey, JW Rabin, DM TI Enhanced synoptic observations: A spacecraft on the other side of the sun SO SYNOPTIC SOLAR PHYSICS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT 18th National-Solar-Observatory/Sacramento-Peak Summer Workshop on Synoptic Solar Physics CY SEP 08-12, 1997 CL SUNSPOT, NM SP Natl Solar Observ, Natl Optical Astron Observ, Natl Sci Fdn, Div Atmospher Sci, NASA, Space Sci Div, Off Space Sci, USAF, Off Sci Res, European Off Aerosp Res & Dev, Asian Off Aerosp Res & Dev, USAF, Air Force Res Lab, Space Hazards Branch AB We discuss an opportunity to greatly enhance synoptic observations by positioning a spacecraft on the other side of the Sun. Such a spacecraft, by gradually increasing its angular separation from the Earth over a year's time, can then be positioned on the other side of the Sun for a year or longer. A possible minimum instrumentation is a Doppler-magnetograph to image the solar surface throughout the mission and advanced radio communications to sound the inner corona from behind. Almost full-Sun magnetic and velocity fields can be obtained by combining observations of the other side of the Sun with earthside observations. This will allow sustained regular observations of evolving magnetic structures and contemporaneous full-Sun synoptic maps to be made. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ruzmaikin, A (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 ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-886733-60-0 J9 ASTR SOC P PY 1998 VL 140 BP 553 EP 561 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BL74T UT WOS:000076547800058 ER PT J AU McLaughlin, WI AF McLaughlin, WI TI Thomson's lamp is dysfunctional SO SYNTHESE LA English DT Article ID NONSTANDARD ANALYSIS AB James Thomson envisaged a lamp which would be turned on for 1 minute, off for 1/2 minute, on for 1/4 minute, etc, ad infinitum. He asked whether the lamp would be on or off at the end of 2 minutes. Use of "internal set theory" ia version of nonstandard analysis), developed by Edward Nelson, shows Thomson's lamp is chimerical; its copy within set theory yields a contradiction. The demonstration extends to placing restrictions on other "infinite tasks" such as Zeno's paradoxes of motion and Kant's First Antinomy. Resolution of such logical-philosophical problems leads to some very general constraints which must be placed upon the syntax of physical theories. In particular, at some scale space and time would appear granular. The suitability of internal set theory for analyzing phenomena is examined, using a paper by Alper and Bridger (1997) to frame the discussion. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McLaughlin, WI (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,301-170S, Pasadena, CA 91109 USA. NR 36 TC 3 Z9 3 U1 1 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0039-7857 J9 SYNTHESE JI Synthese PY 1998 VL 116 IS 3 BP 281 EP 301 DI 10.1023/A:1005045200162 PG 21 WC History & Philosophy Of Science; Philosophy SC History & Philosophy of Science; Philosophy GA 178JV UT WOS:000079263300001 ER PT J AU Mankins, JC AF Mankins, JC TI Can satellite power shine? SO TECHNOLOGY REVIEW LA English DT Letter C1 NASA, Washington, DC 20546 USA. RP Mankins, JC (reprint author), NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MASS INST TECHNOL PI CAMBRIDGE PA BUILDING W59, CAMBRIDGE, MA 02139 USA SN 0040-1692 J9 TECHNOL REV JI Technol. Rev. PD JAN-FEB PY 1998 VL 100 IS 9 BP 6 EP 6 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA YP103 UT WOS:000071241500002 ER PT S AU Yee, R Robbins, FL AF Yee, R Robbins, FL BE Lewis, H TI Airborne blind pointer SO TELESCOPE CONTROL SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Telescope Control Systems III CY MAR 20-21, 1998 CL KONA, HI SP Soc Photo Opt Instrumentat Engineers, European So Observatory, Amer Astron Soc, Astron Soc Pacific, Canadian Astron Soc DE telescope pointing; Blind Pointer; navigation; GPS; SOFIA; KAO AB A candidate Blind Pointer system for the Stratospheric Observatory For Infrared Astronomy (SOFIA) telescope was developed and tested on a telescope aboard the Kuiper Airborne Observatory (KAO). Once an operator inputs the celestial target's coordinates, the Blind Pointer can steer an aircraft and point an airborne telescope to within the focal plane's field-of-view without optical feedback. The Blind Pointer converts the desired stellar object's Right Ascension (RA) and Declination (DEC) into an aircraft heading and telescope pointing-error signals. The Blind Pointer utilizes a Global Positioning System (GPS) receiver integrated with an Inertial Navigation System (INS) controlled by a PC-clone computer. This candidate Blind Pointer offers significant advantages over the present system aboard the KAO: fewer components, greater observation efficiencies, increased accuracy, and simpler design. A patent has been filed for the Blind Pointer. Although the Blind Pointer was developed for airborne telescopes, other applications can exploit this technology. This paper describes the Blind Pointer prototype and flight test results from local and New Zealand deployment flights. C1 NASA, Ames Res Ctr, Space Projects Div, Moffett Field, CA 94035 USA. RP Yee, R (reprint author), NASA, Ames Res Ctr, Space Projects Div, Mail Stop 244-30, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 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 0-8194-2798-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3351 BP 32 EP 39 DI 10.1117/12.308820 PG 8 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL20B UT WOS:000074660800004 ER PT S AU Rahman, ZH Spanos, JT Laskin, RA AF Rahman, ZH Spanos, JT Laskin, RA BE Lewis, H TI Multi-axis vibration isolation, suppression and steering system for space observational applications SO TELESCOPE CONTROL SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Telescope Control Systems III CY MAR 20-21, 1998 CL KONA, HI SP Soc Photo Opt Instrumentat Engineers, European So Observatory, Amer Astron Soc, Astron Soc Pacific, Canadian Astron Soc DE isolation; vibration isolation; vibration control; hexapod; suppression; steering; pointing AB The paper describes an actively controlled six-axis orthogonal hexapod mount that provides vibration isolation, suppression and steering capabilities for space observational systems. Experimental results for vibration isolation is presented. The results show that though the passive-only isolation reduces disturbance propagation significantly, the combination of active and passive isolation provides the best option. The active stage reduces the propagation over the passive-only case by additional 35 dB in the mid frequency range of 10-100Hz. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rahman, ZH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 4 Z9 4 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 0-8194-2798-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3351 BP 73 EP 81 DI 10.1117/12.308821 PG 9 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL20B UT WOS:000074660800008 ER PT S AU Kuiper, TBH Leflang, JG Trinh, T AF Kuiper, TBH Leflang, JG Trinh, T BE Lewis, H TI Reliable customized control software in an R & D environment SO TELESCOPE CONTROL SYSTEMS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Telescope Control Systems III CY MAR 20-21, 1998 CL KONA, HI SP Soc Photo Opt Instrumentat Engineers, European So Observatory, Amer Astron Soc, Astron Soc Pacific, Canadian Astron Soc DE configuration management; custom software; monitor and control; radio astronomy; Tcl/Tk AB Scheduled among the deep space communications activities of the 70-m antennas of the NASA Deep Space Network (DSN) are diverse astronomical observing programs with different requirements. For example, the US Space VLBI Project puts great emphasis on reliability for a few well-defined types of observations, for which the software is essentially frozen for the duration of the Project. On the other hand, Solar System Radar research and observations of regions of star formation need ongoing development, sometimes in real-time, of data acquisition and monitor and control software. This paper describes the methodology by which we can allow each user or project a high degree of customization. To do this we rely on a mixture of public domain software (e.g. Perl, Tcl, Tk, PGPLOT) and locally developed software. The scheme allows the software configuration in the Radio Astronomy Controller to be switched to an observer's or project's specific configuration within seconds, including specific releases of public domain software. At the core of the Radio Astronomy Controller is a server that controls the R&D equipment. The behavior of this server is largely determined by Tcl scripts, which are customized for the observer or project. An observer working interactively can use a customized Tk client to direct the server via TCP, as well as DSN operational (non-R&D) equipment via another server which communicates with DSN controllers. A project or user may alternatively run a client which is specialized for unattended operations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kuiper, TBH (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 SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2798-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3351 BP 254 EP 264 DI 10.1117/12.308812 PG 11 WC Astronomy & Astrophysics; Optics SC Astronomy & Astrophysics; Optics GA BL20B UT WOS:000074660800027 ER PT J AU Riishojgaard, LP AF Riishojgaard, LP TI A direct way of specifying flow-dependent background error correlations for meteorological analysis systems SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID DATA ASSIMILATION; OBJECTIVE ANALYSIS; AIRCRAFT; OZONE AB Identifying a viable strategy for specifying the background error covariance remains an important problem in meteorological data assimilation. From a Formal point of view the number of independent parameters needed for this is n(2)/2 when n is the dimension of the model state space. In most analysis systems used in operational mode at the present time, the error covariance is modeled using assumptions about homogeneity and isotropy, and the resulting background error covariance matrix thus does not depend on the state of the atmosphere. In this paper, wt propose a simple and inexpensive method for specifying univariate background error correlations in terms of the background field itself. We illustrate the positive impact of the implementation of this model by a simple example in which we reconstruct a total ozone field from a sparse set of observations. We finally discuss the generalization of the basic idea involved to univariate correlations for general meteorological models. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Riishojgaard, LP (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. NR 21 TC 62 Z9 63 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD JAN PY 1998 VL 50 IS 1 BP 42 EP 57 DI 10.1034/j.1600-0870.1998.00004.x PG 16 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA YY293 UT WOS:000072132600004 ER PT B AU Dobinson, ER Raskin, RG AF Dobinson, ER Raskin, RG GP IEEE, COMP SOC TI Remote access to Earth science data by content, space, and time SO TENTH INTERNATIONAL CONFERENCE ON SCIENTIFIC AND STATISTICAL DATABASE MANAGEMENT - PROCEEDINGS LA English DT Proceedings Paper CT 10th International Conference on Scientific and Statistical Database Management CY JUL 01-03, 1998 CL CAPRI, ITALY SP Ist Analisi Sistemi Informat, Consiglio Nazl Ricerche, Telecom Italia, Agenzia Autonoma Cura Soggiorno Turismo Capri, ENEA, Univ Roma Tre, Dept Informat & Autom AB For the past several years a small team of developers at the Jet Propulsion Laboratory and ar the University of Rhode Island have been working on a system to provide Earth scientists with access to remotely held data sets stored in various standard formats as though the data were local to the user's application. This capability requires not only interoperability among multiple formats and remote access to data via the internet, bur also the ability to identify and select small subsets of data by space, time, and measured parameter. This demo presents the combination of tot http-based client/server application that facilitates internet access to Earth science data coupled with a Java applet GUI that allows the user to graphically select data based on spatial and temporal coverage plots and scientific parameters. Access to data by values of the measured parameters is feasible via the same indexing schemes used for space and rime, and work to include this capability is in progress. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dobinson, ER (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 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 0-8186-8575-1 PY 1998 BP 222 EP 225 DI 10.1109/SSDM.1998.688128 PG 4 WC Computer Science, Information Systems SC Computer Science GA BL34C UT WOS:000075209000023 ER PT J AU Liu, HS AF Liu, HS TI Phase modulation effect of the Rubincam insolation variations on climate change SO THEORETICAL AND APPLIED CLIMATOLOGY LA English DT Article ID VOSTOK ICE CORE; ORBITAL PARAMETERS; GLACIATION CYCLES; EVOLUTION; RECORDS; SYSTEM; EARTH; TERMS; VIEW AB For astronomical seasons, Rubincam insolation deviations at latitude 65 degrees N varied from 218.50 Wm(-2) to 225.75 Wm(-2) (3%). The periodicity of the insolation cycles varied from 367 Kyr to 44.7 Kyr (20%) due to phase shift. Phase shift of insolation variations can induce asymmetry of the insolation cycles, permitting rapid melting and prolonged glaciation of ice sheets to occur. For instance, an abnormal decrease of the insolation frequency during the longer period of glacial interval would prolong glaciation into deep ice age. In this study, we apply Rubincam's insolation equations to investigate the phase shift effect of insolation variations on climate change. Using complex transforms of the changing insolation, we have detected a phase modulation signal in the insolation variations. As a result, an especially new and interesting series of the phase-related insolation pulsation is established. The phase modulated insolation is then introduced as a forcing function into energy balance climate models. Results of model computations shed new insights into the spectrum of the paleoclimatic proxy-data. It is shown that phase modulation of the insolation may provide an appropriate and complete external forcing mechanism to which the climate system would respond. The 100 Kyr cycle of the frequency modulation of the Rubincam's insolation variations does seem adequate to change the climate. C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Liu, HS (reprint author), NASA, Goddard Space Flight Ctr, Geodynam Branch, Code 921, Greenbelt, MD 20771 USA. NR 38 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-798X J9 THEOR APPL CLIMATOL JI Theor. Appl. Climatol. PY 1998 VL 61 IS 3-4 BP 217 EP 229 DI 10.1007/s007040050066 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156WJ UT WOS:000078025000009 ER PT J AU Farassat, F Brentner, KS AF Farassat, F Brentner, KS TI The acoustic analogy and the prediction of the noise of rotating blades SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article; Proceedings Paper CT International Conference on Fluid Dynamics in Honor of James Lighthill CY NOV 06-08, 1996 CL TALLAHASSEE, FLORIDA SP Florida State Univ, Dept Math, Florida State Univ, Program Comp Sci & Engn, Florida State Univ, Supercomp Comp Res Inst ID ROTOR AB The acoustic analogy was introduced into acoustics by Lighthill in 1952 to understand and predict the noise generated by the jet of an aircraft turbojet engine. The idea behind the acoustic analogy is simple but powerful. The entire noise generation process is mathematically reduced to the study of wave propagation in a quiescent medium with the effect of flow replaced by quadrupole sources. In jet noise theory, Lighthill was able to obtain significant and useful qualitative results from the acoustic analogy. The acoustic analogy has influenced the theoretical and experimental research on jet noise since the early 1950s. This paper, however, focuses on another area in which the acoustic analogy has had a significant impact, namely the prediction of the noise of rotating machinery. The governing equation for this problem was derived by Ffowcs Williams and Hawkings in 1969. This equation is a wave equation for perturbation density with three source terms, which have become known as thickness, loading, and the quadrupole source terms, respectively. The Ffowcs Williams-Hawkings (FW-H) equation has been used for the successful prediction of the noise of helicopter rotors, propellers, and fans. Several reasons account for the success and popularity of the acoustic analogy. First, the problems of acoustics and aerodynamics are separated. Second, because the FW-H equation is linear, powerful analytical methods from linear operator theory can be used to obtain closed-form solutions. Third, advances in digital computers and computational fluid dynamics algorithms have resulted in high-resolution near-field aerodynamic calculations that are suitable for noise prediction. We present some of the mathematical results for noise prediction based on the FW-H equation, including examples for helicopter rotors. In particular, we discuss the prediction of blade-vortex interaction noise and high-speed impulsive noise of helicopter rotors. For high-speed propellers, we briefly discuss the derivation of a singularity-free solution of the FW-H equation for a supersonic panel on a blade. C1 NASA, Langley Res Ctr, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. RP Farassat, F (reprint author), NASA, Langley Res Ctr, Fluid Mech & Acoust Div, Hampton, VA 23681 USA. NR 27 TC 18 Z9 25 U1 2 U2 12 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD JAN PY 1998 VL 10 IS 1-4 BP 155 EP 170 DI 10.1007/s001620050056 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YY659 UT WOS:000072170700010 ER PT J AU Goldstein, ME Wundrow, DW AF Goldstein, ME Wundrow, DW TI On the environmental realizability of algebraically growing disturbances and their relation to Klebanoff modes SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article; Proceedings Paper CT International Conference on Fluid Dynamics in Honor of James Lighthill CY NOV 06-08, 1996 CL TALLAHASSEE, FLORIDA SP Florida State Univ, Dept Math, Florida State Univ, Program Comp Sci & Engn, Florida State Univ, Supercomp Comp Res Inst ID TOLLMIEN-SCHLICHTING WAVES; FREE-STREAM TURBULENCE; PLATE BOUNDARY-LAYER; LEADING-EDGE; DISTORTION; EVOLUTION; VORTICITY; FLOW; RECEPTIVITY AB A theoretical explanation of some experimentally observed phenomena associated with the so-called Klebanoff modes is obtained by analyzing the flow over a finite thickness flat plate resulting from a small-amplitude distortion imposed on the upstream mean flow. The analysis shows (among other things) how the stretching of the vortex lines around the plate leads to streamwise vorticity at the plate surface, which then produces a streamwise velocity perturbation within the boundary layer that can be related to the experimentally observed Klebanoff mode. The complete evolution of this flow must be found by solving the boundary-region equations of Kemp (1951) and Davis and Rubin (1980), but a limiting analytical solution can also be obtained. Since the initial growth of the boundary-layer disturbance is nearly algebraic, our results demonstrate how the algebraically growing disturbances promoted by Landahl and others can be generated by a realistic external-disturbance environment. The relationship between these results and various bypass transition mechanisms is discussed. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NyMA Inc, NASA, Lewis Res Ctr Grp, Cleveland, OH 44135 USA. RP Goldstein, ME (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 38 TC 32 Z9 34 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD JAN PY 1998 VL 10 IS 1-4 BP 171 EP 186 DI 10.1007/s001620050057 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YY659 UT WOS:000072170700011 ER PT J AU Seiner, JM AF Seiner, JM TI A new rational approach to jet noise reduction SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article; Proceedings Paper CT International Conference on Fluid Dynamics in Honor of James Lighthill CY NOV 06-08, 1996 CL TALLAHASSEE, FLORIDA SP Florida State Univ, Dept Math, Florida State Univ, Program Comp Sci & Engn, Florida State Univ, Supercomp Comp Res Inst AB This paper offers a new rational approach to jet noise suppression methodology. The tools required to implement such an approach are discussed. These involve the use of global velocimetry to measure those Lighthill turbulent stress tensor terms thought most important to noise generation. The framework of the dynamic systems model as it applies to the development of a noise suppression model is discussed, as well as the latest results on the development of an actuator for control input. The dynamic systems model offers a unique opportunity to study the influence of a concept noise reduction scheme on noise reduction through appropriate algorithms that relate turbulent jet processes to noise. C1 NASA, Langley Res Ctr, Jet Noise Lab, Hampton, VA 23681 USA. RP Seiner, JM (reprint author), NASA, Langley Res Ctr, Jet Noise Lab, Hampton, VA 23681 USA. NR 19 TC 14 Z9 14 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD JAN PY 1998 VL 10 IS 1-4 BP 373 EP 383 DI 10.1007/s001620050070 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YY659 UT WOS:000072170700024 ER PT S AU Chernov, AA AF Chernov, AA BE Fornari, R Paorici, C TI Step and surface roughening - An introduction SO THEORETICAL AND TECHNOLOGICAL ASPECTS OF CRYSTAL GROWTH SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 10th International Summer School on Crystal Growth CY JUN 01-06, 1998 CL RIMINI, ITALY SP Int Org Crystal Growth, Italian Assoc Crystallog, Crystal Growth Sect, Natl Grp Struct Matter Natl Res Council, Intl Union Crystalog, German Assoc Crystal Growth DE anisotropy; fluctuations; interface; renormalization theory; roughening; roughening temperature; pinning ID TERRACE-WIDTH DISTRIBUTIONS; X-RAY-SCATTERING; NI(113) SURFACE; CRYSTAL-GROWTH; CLEAN SI(111); TRANSITION; MORPHOLOGY; MICROSCOPY; SI(001); MODEL AB Thermal fluctuations leading to step and interface roughening are described making use of a concept of continuous interface pinned by a lattice potential. Systematic detailed outline of basic relations is given for those who are willing to deeper understand the roughening concept but is not professionally involved in the phase transition and renormalizations group theory. Some experimental examples are presented. C1 Univ Space Res Assoc, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Chernov, AA (reprint author), Univ Space Res Assoc, Bldg 4481,ES75, Huntsville, AL 35812 USA. NR 51 TC 4 Z9 4 U1 0 U2 1 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-806-0 J9 MATER SCI FORUM PY 1998 VL 276-2 BP 57 EP 69 PG 13 WC Crystallography; Materials Science, Multidisciplinary SC Crystallography; Materials Science GA BL15Z UT WOS:000074517000003 ER PT S AU Chernov, AA AF Chernov, AA BE Fornari, R Paorici, C TI Step kinetics by one-dimensional "nucleation" SO THEORETICAL AND TECHNOLOGICAL ASPECTS OF CRYSTAL GROWTH SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 10th International Summer School on Crystal Growth CY JUN 01-06, 1998 CL RIMINI, ITALY SP Int Org Crystal Growth, Italian Assoc Crystallog, Crystal Growth Sect, Natl Grp Struct Matter Natl Res Council, Intl Union Crystalog, German Assoc Crystal Growth DE attachments; detachments; kink; nucleation; rate anisotropy; roughness; step; velocity ID CRYSTAL-GROWTH AB At moderate and high supersaturations, the kinks generated by detachment of molecules from a straight singular step, mutually annihilate. Therefore, generation of kinks by attachment of molecules from the surrounding and making molecular pairs-one-dimensional nuclei-is important. Such 1D nucleation rate is considered. The step rate via the 1D nucleation and the kink propagation rates is expressed analytically for a step declined, on average, from singular orientation. The resulting azimuthal anisotropy of the step rate within the face is expressed via kinetic rather than via standard thermodynamic parameters. C1 Univ Space Res Assoc, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Chernov, AA (reprint author), Univ Space Res Assoc, Bldg 4481,ES75, Huntsville, AL 35812 USA. NR 19 TC 11 Z9 12 U1 1 U2 3 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-806-0 J9 MATER SCI FORUM PY 1998 VL 276-2 BP 71 EP 78 PG 8 WC Crystallography; Materials Science, Multidisciplinary SC Crystallography; Materials Science GA BL15Z UT WOS:000074517000004 ER PT S AU Chernov, AA AF Chernov, AA BE Fornari, R Paorici, C TI Subsurface ordering and kinetic coefficient for melt growth SO THEORETICAL AND TECHNOLOGICAL ASPECTS OF CRYSTAL GROWTH SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT 10th International Summer School on Crystal Growth CY JUN 01-06, 1998 CL RIMINI, ITALY SP Int Org Crystal Growth, Italian Assoc Crystallog, Crystal Growth Sect, Natl Grp Struct Matter Natl Res Council, Intl Union Crystalog, German Assoc Crystal Growth DE density waves; growth rate; interface; kinetic coefficient; liquid structure; melt; metals; subsurface ordering ID SOLID-LIQUID INTERFACE; MOLECULAR-DYNAMICS; CRYSTALLIZATION; SOLIDIFICATION; MOBILITY; CRYSTALS; LEAD; HE-4 AB Lattice model of liquid phase often used to analyze crystal interface and growth processes does not take into account spatial disorder of molecules in the liquid and in the interface region. Some attempts to get rid of these limitations are briefly reviewed. Linear kinetic coefficient of proportionality between driving force for crystallization and velocity of rough interface in a melt is outlined in terms of wavevectors characterizing density waves which superposition presents melt structure. C1 Univ Space Res Assoc, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. RP Chernov, AA (reprint author), Univ Space Res Assoc, Bldg 4481,ES75, Huntsville, AL 35812 USA. NR 30 TC 0 Z9 0 U1 0 U2 0 PU TRANSTEC PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-806-0 J9 MATER SCI FORUM PY 1998 VL 276-2 BP 79 EP 86 PG 8 WC Crystallography; Materials Science, Multidisciplinary SC Crystallography; Materials Science GA BL15Z UT WOS:000074517000005 ER PT S AU Winfree, WP Heath, DM AF Winfree, WP Heath, DM BE Snell, JR Wurzbach, RN TI Thermal diffusivity imaging of aerospace materials and structures SO THERMOSENSE XX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Thermosense XX CY APR 14-16, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers AB Thermographic imaging is increasingly being utilized for inspection and characterization of materials and structures. Thermal diffusivity imaging provides a means for quantitative characterization of a material which is independent of apparatus and measurement configuration. This enables more precise imaging of variations in the material or structure needed to track changes resulting from fatigue or aging processes. To reduce the thermal images to a diffusivity image, a nonlinear least squares fitting routine is used to minimized the difference between measured time records of temperature and an analytical solution for the thermal response of the material to a thermal heat flux. This algorithm is applied point by point to time sequences of scanned LR images. An advantage of this technique is that the entire time record is used, from the initial heating impulse until thermal equilibrium is reached, rather than just one or two points of the thermal response. To reduce the processing time the analytical solution is divided into two parts, one for the early time response and one for the late time response. Critical to accurate measurement of the thermal diffusivity, is the time intervals between images. A criteria is presented for establishing the optimum time interval, based on an initial estimate of thermal diffusivity and the thickness of the part. In addition, a relationship between signal to noise in the thermal images and variance in the diffusivity images is delineated. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Winfree, WP (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 16 Z9 16 U1 0 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 0-8194-2810-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3361 BP 282 EP 290 DI 10.1117/12.304739 PG 9 WC Instruments & Instrumentation; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Materials Science; Optics GA BL17D UT WOS:000074540100031 ER PT S AU Cramer, KE Winfree, WP AF Cramer, KE Winfree, WP BE Snell, JR Wurzbach, RN TI Thermographic detection and quantitative characterization of corrosion by application of thermal line source SO THERMOSENSE XX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Thermosense XX CY APR 14-16, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE infrared; thermal; NDE; corrosion AB Recent advances in thermal imaging technology have spawned a number of new thermal nondestructive evaluation (NDE) techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique for aircraft. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a matter of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post-processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. NASA Langley Research Center has developed a thermal NDE technique designed to image and quantitatively characterize the thickness of thin aluminum sheets. The technique involves the movement of a thermal line source across the outer surface of a sample followed by an infrared imager at a fixed distance behind the line source. Images of the material loss due to corrosion are reconstructed from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to reconstruct images of flaws. The application of the thermal line source coupled with the analysis technique represents a significant improvement in the quantification of flaws over conventional thermal imaging. Results of laboratory experiments on specimens with fabricated material loss regions will be presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling to optimize the technique and reduce the data The experimental results will be compared with simulations to demonstrate the utility of such an approach. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Cramer, KE (reprint author), NASA, Langley Res Ctr, 3B E Taylor St,Mail Stop 231, Hampton, VA 23681 USA. NR 0 TC 12 Z9 12 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 0-8194-2810-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3361 BP 291 EP 300 DI 10.1117/12.304740 PG 10 WC Instruments & Instrumentation; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Materials Science; Optics GA BL17D UT WOS:000074540100032 ER PT S AU Plotnikov, YA Winfree, WP AF Plotnikov, YA Winfree, WP BE Snell, JR Wurzbach, RN TI Advanced image processing for defect visualization in infrared thermography SO THERMOSENSE XX SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Thermosense XX CY APR 14-16, 1998 CL ORLANDO, FL SP Soc Photo Opt Instrumentat Engineers DE infrared thermography; image analysis; inverse problem; thermal tomography; nondestructive evaluations AB Results of a defect visualization process based on pulse infrared thermography are presented. Algorithms have been developed to reduce the amount of operator participation required in the process of interpreting thermographic images. The algorithms determine the defect's depth and size from the temporal and spatial thermal distributions that exist on the surface of the investigated object following thermal excitation. A comparison of the results from thermal contrast, time derivative, and phase analysis methods for defect visualization are presented. These comparisons are based on three dimensional simulations of a test case representing a plate with multiple delaminations. Comparisons are also based on experimental data obtained from a specimen with flat bottom holes and a composite panel with delaminations. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Plotnikov, YA (reprint author), NASA, Langley Res Ctr, MS 231, Hampton, VA 23681 USA. NR 0 TC 7 Z9 7 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 0-8194-2810-8 J9 P SOC PHOTO-OPT INS PY 1998 VL 3361 BP 331 EP 338 DI 10.1117/12.304745 PG 8 WC Instruments & Instrumentation; Materials Science, Characterization & Testing; Optics SC Instruments & Instrumentation; Materials Science; Optics GA BL17D UT WOS:000074540100037 ER PT B AU Schneider, F Easterbrook, SM Callahan, JR Holzmann, GJ AF Schneider, F Easterbrook, SM Callahan, JR Holzmann, GJ GP IEEE TI Validating requirements for fault tolerant systems using model checking SO THIRD INTERNATIONAL CONFERENCE ON REQUIREMENTS ENGINEERING - PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Requirements Engineering CY APR 06-10, 1998 CL COLORADO SPRINGS, CO SP IEEE Comp Soc, Tech Council Software Engn, FUJITSU, INCOSE, MCI AB Model checking is shown to be an effective tool in validating the behavior of a fault tolerant embedded spacecraft controller. The case study presented here shows that by judiciously abstracting away extraneous complexity, the state space of the mode could be exhaustively searched allowing critical functional requirements to be validated down to the design level. Abstracting away detail not germane to the problem of interest leaves by definition a partial specification behind. The success of this procedure shows that it is feasible to effectively validate a partial specification with this technique. Three anomalies were found in the system. One was an error in the detailed requirements, and the other two were missing/ambiguous requirements. Because the method allows validation of partial specifications, it is also an effective approach for maintaining fidelity between a co-evolving specification and an implementation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schneider, F (reprint author), CALTECH, Jet Prop Lab, MSA 125-233, Pasadena, CA 91109 USA. NR 0 TC 17 Z9 17 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 0-8186-8356-2 PY 1998 BP 4 EP 13 DI 10.1109/ICRE.1998.667803 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BK74F UT WOS:000073310800001 ER PT B AU Hammer, T Huffman, L AF Hammer, T Huffman, L GP IEEE TI Automated requirements management - Beware HOW you use tools - An experience report SO THIRD INTERNATIONAL CONFERENCE ON REQUIREMENTS ENGINEERING - PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Requirements Engineering CY APR 06-10, 1998 CL COLORADO SPRINGS, CO SP IEEE Comp Soc, Tech Council Software Engn, FUJITSU, INCOSE, MCI DE requirements; requirement management tools AB At NASA and across industry, with multiple release projects, requirement storage is a volatile, dynamic process. The skill with which a project maintains, keeps current, tracks, and traces its set of requirements affects every phase of the project's software development life cycle - including maintenance. the ability to effectively manage requirements influences, months and/or years before project completion, how, when, and how expensively completion will take place. The Software Assurance Technology Center (SATC) at NASA Goddard Space Flight Center is working to continually evaluate the requirement activities of a multi-billion dollar project. This task requires that the SATC evaluate the project's tools, specifically the requirement database management tool. The objective of this paper is to identify a major failing in the use of requirement management tools that causes loss of data, loss of data integrity, and loss of tool functionality. It will also show that bringing engineers and database designers together to define tool use is mandatory; and that each discipline's experience and expertise is required far successful tool implementation. Using experiences from a NASA project, we will demonstrate some potential risks when a requirement management tool is incorrectly used, and how this fatal flaw plants the seeds of requirement management destruction and consequent project overruns. This information will benefit any project considering or using requirement management tools. C1 NASA, GSFC, Greenbelt, MD 20771 USA. RP Hammer, T (reprint author), NASA, GSFC, Bld 6 Code 300, Greenbelt, MD 20771 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 0-8186-8356-2 PY 1998 BP 34 EP 40 DI 10.1109/ICRE.1998.667806 PG 7 WC Computer Science, Software Engineering SC Computer Science GA BK74F UT WOS:000073310800004 ER PT S AU Fleming, GA Gorton, SA AF Fleming, GA Gorton, SA BE Tomasini, EP TI Measurement of rotorcraft blade deformation using Projection Moire Interferometry SO THIRD INTERNATIONAL CONFERENCE ON VIBRATION MEASUREMENTS BY LASER TECHNIQUES: ADVANCES AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd International Conference on Vibration Measurements by Laser Techniques CY JUN 16-19, 1998 CL ANCONA, ITALY SP Italian Assoc Laser Velocimetry, Univ Studi Ancona, Dipartimento Meccan, AEA SArl, API Raffineria Ancona SpA, DAYCO PTI SpA, Merloni Elettrodomestici, NUOVO PIGNONE SpA, Opto & Laser Europe, TEUCO Guzzini Srl, Amer Concrete Inst Int, AMA, Fachverband Sensorik e V, Acoust Soc Japan, Bulgarreklama, GISI, Gruppo Imprese Strumentazione Italia, Int Assoc Hydraul Res, Int Measurement Confederat, Soc Automot Engineers Japan, Opt Soc Amer, Soc Automot Engineers, Soc Exptl Mech, Soc Instrument & Control Engineers DE Projection Moire Interferometry; PMI; rotorcraft; helicopter; blade; deformation; deflection AB Projection Moire Interferometry (PMI) has been used to obtain near instantaneous, quantitative blade deformation measurements of a generic rotorcraft model at several test conditions. These laser-based measurements provide quantitative, whole field, dynamic blade deformation profiles conditionally sampled as a function of rotor azimuth, The instantaneous nature of the measurements permits computation of the mean and unsteady blade deformation, blade bending, and twist. The PMI method is presented, and the image processing steps required to obtain quantitative deformation profiles from PMI interferograms are described. Experimental results are provided which show blade bending, twist, and unsteady motion. This initial proof-of-concept test has demonstrated the capability of PMI to acquire accurate, full field rotorcraft blade deformation data. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fleming, GA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 8 Z9 8 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 0-8194-2863-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3411 BP 514 EP 527 DI 10.1117/12.307738 PG 14 WC Acoustics; Instruments & Instrumentation; Optics SC Acoustics; Instruments & Instrumentation; Optics GA BL17F UT WOS:000074540800057 ER PT S AU Fleming, GA Buehrle, RD Storaasli, OL AF Fleming, GA Buehrle, RD Storaasli, OL BE Tomasini, EP TI Modal analysis of an aircraft fuselage panel using experimental and finite-element techniques SO THIRD INTERNATIONAL CONFERENCE ON VIBRATION MEASUREMENTS BY LASER TECHNIQUES: ADVANCES AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd International Conference on Vibration Measurements by Laser Techniques CY JUN 16-19, 1998 CL ANCONA, ITALY SP Italian Assoc Laser Velocimetry, Univ Studi Ancona, Dipartimento Meccan, AEA SArl, API Raffineria Ancona SpA, DAYCO PTI SpA, Merloni Elettrodomestici, NUOVO PIGNONE SpA, Opto & Laser Europe, TEUCO Guzzini Srl, Amer Concrete Inst Int, AMA, Fachverband Sensorik e V, Acoust Soc Japan, Bulgarreklama, GISI, Gruppo Imprese Strumentazione Italia, Int Assoc Hydraul Res, Int Measurement Confederat, Soc Automot Engineers Japan, Opt Soc Amer, Soc Automot Engineers, Soc Exptl Mech, Soc Instrument & Control Engineers DE Electro-Optic Holography; EOH; aircraft; fuselage; interferogram; FEM; validation AB The application of Electro-Optic Holography (EOH) for measuring the center bay vibration modes of an aircraft fuselage panel under forced excitation is presented. The requirement of free-free panel boundary conditions made the acquisition of quantitative EOH data challenging since large scale rigid body motions corrupted measurements of the high frequency vibrations of interest. Image processing routines designed to minimize effects of large scale motions were applied to successfully resurrect quantitative EOH vibrational amplitude measurements from extremely noisy data. EOH and Scanning Laser Doppler Vibrometry (SLDV) results have been used to validate and update finite element models of the fuselage panel. Various modeling techniques were evaluated for characterization of the panel normal modes at frequencies up to 1000 Hz. These models are briefly described, and comparisons between computational predictions and experimental measurements are presented. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Fleming, GA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 0 TC 5 Z9 5 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-2863-9 J9 P SOC PHOTO-OPT INS PY 1998 VL 3411 BP 537 EP 548 DI 10.1117/12.307740 PG 12 WC Acoustics; Instruments & Instrumentation; Optics SC Acoustics; Instruments & Instrumentation; Optics GA BL17F UT WOS:000074540800059 ER PT B AU Mehrotra, P Van Rosendale, J Zima, H AF Mehrotra, P Van Rosendale, J Zima, H GP IEEE IEEE TI Solving irregular problems with High Performance Fortran SO THIRD WORKING CONFERENCE ON MASSIVELY PARALLEL PROGRAMMING MODELS, PROCEEDINGS LA English DT Proceedings Paper CT 3rd Working Conference on Massively Parallel Programming Models (MPPM97) CY NOV 12-14, 1997 CL LONDON, ENGLAND SP Fujitsu European Ctr Informat Technol (FECIT) AB High Performance Fortran (HPF) provides a high-level interface for data-parallel scientific applications, while delegating to the compiler the task of generating an explicitly parallel message-passing program. The main objective of this paper is to study the applicability of the language to a class of irregular scientific applications. After giving an outline of developments that led to HPF and shortly explaining its major features, we discuss a variety of approaches for solving multiblock problems and applications dealing with unstructured meshes. We show that the efficient solution of these problems does not only need the full range of the HPF Approved Extensions, but also requires additional features such as the explicit control of communication schedules and support for value-based alignment. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Mehrotra, P (reprint author), NASA, Langley Res Ctr, ICASE, MS 132C, Hampton, VA 23681 USA. NR 0 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 0-8186-8427-5 PY 1998 BP 2 EP 11 DI 10.1109/MPPM.1997.715956 PG 10 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BM17N UT WOS:000077910500001 ER PT B AU Beaman, BG Rao, GM AF Beaman, BG Rao, GM BE Frank, HA Seo, ET TI Hybrid battery and flywheel energy storage system for LEO spacecraft SO THIRTEENTH ANNUAL BATTERY CONFERENCE ON APPLICATIONS AND ADVANCES LA English DT Proceedings Paper CT 13th Annual Battery Conference on Applications and Advances CY JAN 13-16, 1998 CL CALIF STATE UNIV, LONG BEACH, LONG BEACH, CA SP Calif State Univ, Long Beach, Coll Engn, Adv Lead Acid Battery Consortium, Amer Inst Aeronaut & Astronaut, Electrochem Soc Inc, Independent Battery Manufacturers Assoc Inc, IEEE Aerosp & Electr Syst Soc, Int Cadmium Assoc, N Amer, So Calif Edison Co, Batteries Int Ltd, Business Commun Co Inc, Darnell Grp, Int Battery Technol Inc, Intertec Int Inc, ITE JEC Press Inc, 7 Mountains Sci Inc HO CALIF STATE UNIV, LONG BEACH AB The use of flywheels as energy storage was probably the second thought after the wheel was invented. With the recent developments in composite materials, magnetic materials and the use of micro processors; flywheel energy storage has wide applications in many facets of our lives. For space vehicles, two counte-rotating wheels are used to produce a flywheel energy storage system (FESS). The initial flight opportunities for this flywheel technology can be used for energy storage in conjunction with existing battery and power subsystem designs. There are also possibilities that this pair of counter rotating FESS's can replace one of the attitude control wheels in the attitude control system (ACS) wheel set. This paper describes the potential combined battery/flywheel energy storage system for aerospace application. Battery charging control schemes and solar array regulation can be augmented with a flywheel system to improve spacecraft performance, allow a alternate energy storage source for single battery systems, reduce the size of the solar array and be used as one of (3 or 4) attitude control wheels. C1 NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20771 USA. RP Beaman, BG (reprint author), NASA, Goddard Space Flight Ctr, Space Power Applicat Branch, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 3 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-4098-1 PY 1998 BP 113 EP 116 DI 10.1109/BCAA.1998.653851 PG 4 WC Engineering, Aerospace; Electrochemistry; Engineering, Electrical & Electronic SC Engineering; Electrochemistry GA BK54D UT WOS:000072520900022 ER PT S AU Scott, K Bambos, N AF Scott, K Bambos, N BE Fargues, MP Hippenstiel, RD TI Formation and maintenance of Self-Organizing Wireless Networks SO THIRTY-FIRST ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS, VOLS 1 AND 2 SE CONFERENCE RECORD OF THE ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS LA English DT Proceedings Paper CT 31st Asilomar Conference on Signals, Systems and Computers CY NOV 02-05, 1997 CL PACIFIC GROVE, CA SP USN, Naval Postgrad Sch, San Jose State Univ, IEEE Signal Proc Soc AB There are numerous military commercial, and scientific applications for mobile wireless networks which are able to self-organize without recourse to any pre-existing infrastructure. We present the Self-Organizing Wireless Adaptive Network (SWAN) protocol, a distributed networking protocol capable of managing such networks. The SWAN approach is based on dynamic topology management with power control, allowing it to adapt gradually to the changing environment instead of periodically discarding the network topology information and rebuilding the network from scratch. In addition, under SWAN control information is distributed instead of being concentrated in a "control phase". This provides significant savings when the acquisition times of the modems are high. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Scott, K (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 COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA SN 1058-6393 BN 0-8186-8316-3 J9 CONF REC ASILOMAR C PY 1998 BP 31 EP 35 PG 5 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BL02V UT WOS:000074080800006 ER PT S AU Matache, A Ritcey, JA AF Matache, A Ritcey, JA BE Fargues, MP Hippenstiel, RD TI Optimum code rates for noncoherent MFSK with errors and erasures decoding over Rayleigh fading channels SO THIRTY-FIRST ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS & COMPUTERS, VOLS 1 AND 2 SE CONFERENCE RECORD OF THE ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS AND COMPUTERS LA English DT Proceedings Paper CT 31st Asilomar Conference on Signals, Systems and Computers CY NOV 02-05, 1997 CL PACIFIC GROVE, CA SP USN, Naval Postgrad Sch, San Jose State Univ, IEEE Signal Proc Soc AB The capacity and cutoff rate of M-ary frequency shift keying (FSK) modulation with noncoherent hard-decisions reception and erasure of unreliable symbols using Viterbi ratio threshold test are calculated for Rayleigh fading channels. Optimum code rates and erasure threshold values are found to minimize the required signal-to-noise ratio for reliable communication. In addition, optimum Reed Solomon codes are found to minimize the signal-to-noise ratio necessary to achieve a code ward error probability of 10(-5). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Matache, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-420, Pasadena, CA 91109 USA. NR 0 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 SN 1058-6393 BN 0-8186-8316-3 J9 CONF REC ASILOMAR C PY 1998 BP 62 EP 66 PG 5 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA BL02V UT WOS:000074080800011 ER PT B AU Borsch, RE Matthewson, C Carter, RB Crotwell, J Woolley, JG Richards, FH AF Borsch, RE Matthewson, C Carter, RB Crotwell, J Woolley, JG Richards, FH GP SAFE SAFE TI Investigation and evaluation of a replacement parachute for the SJU-5/A escape system SO THIRTY-SIXTH ANNUAL SYMPOSIUM SAFE ASSOCIATION, PROCEEDINGS LA English DT Proceedings Paper CT 36th Annual SAFE Symposium CY SEP 14-16, 1998 CL PHOENIX, AZ SP SAFE Assoc AB Following its selection to produce the F/A-18 and TF-18 combat aircraft, the McDonnell Douglas Corporation selected the Martin Baker Aircraft Company, Ltd. to provide the aircrew automated ejection seat escape system. The resulting SJU-5/A and SJU-6/A escape systems were subsequently developed and qualified in 1981. The parachute assembly used in these escape systems was the Ge Type 1000 Aeroconical personnel recovery system. This parachute has an inflated diameter of 5.2m (17 ft) and incorporates low porosity ripstop nylon cloth in its gores and two vents at the rear of the canopy to provide steerability. Since its introduction, several aircrew mishaps have taken place in which the high descent rate of the Ge Type 1000 parachute was listed as the primary causal factor for the injuries. One of these mishaps occurred in 1995 during a rest flight of the NASA X-31 aircraft which incorporated the SJU-5/A escape system. After the aircrewmember sustained injuries during parachute landing, NASA Headquarters directed that a program be established to investigate alternate parachute systems to replace the GO Type 1000 parachute assembly. The Canadian National Defence Headquarters also expressed interest in this effort and agreed to jointly participate in the program with NASA. Utilizing the test facilities at the Naval Air Warfare Center Weapons Division, China Lake, CA, various parachute canopies were evaluated through a series of Drop Tower tests, High- and Low-Speed Air Drop tests, and High-Speed Vehicle Launch Track tests. A series of in-flight ejection tests were also conducted to evaluate the performance of the selected replacement parachute under actual operational conditions. The successful results from these tests demonstrated that the ACES-II canopy modified for usage with the SJU-5/A escape system is a viable replacement for the Ge Type 1000 Aeroconical parachute canopy. C1 NASA, Dryden Flight Res Ctr, Washington, DC 20546 USA. RP Borsch, RE (reprint author), NASA, Dryden Flight Res Ctr, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SAFE ASSOC PI YONCALLA PA 4995 SCOTTS VALLEY RD, PO BOX 490, YONCALLA, OR 97499-0490 USA PY 1998 BP 72 EP 82 PG 11 WC Engineering, Aerospace SC Engineering GA BL94R UT WOS:000077255200011 ER PT S AU Kiang, RK AF Kiang, RK BE Cogswell, CJ Conchello, JA Lerner, JM Lu, T Wilson, T Katzir, A TI Multitemporal multispectral classification of global vegetation SO THREE-DIMENSIONAL AND MULTIDIMENSIONAL MICROSCOPY: IMAGE ACQUISITION AND PROCESSING V, PROCEEDINGS OF SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on 3-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing V CY JAN 27-29, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers, Int Biomed Opt Soc, Santa Barbara Instrument Grp, Kaiser Opt Syst Inc DE remote sensing; multispectral classification; multitemporal; vegetation index; global warming AB Surface vegetation is an important link in the coupling between the atmosphere and the biosphere. Monitoring the condition of vegetation cover on the Earth surface is essential for detecting the changes in climate. Advanced Very-High Resolution Radiometer (AVHRR) 10-day composite data in 1x1 degree resolution from NASA/GSFC and a global vegetation ground truth in the same resolution from the University of Maryland's Geography Department are used in this study. A fully connected multilayer neural network is used for supervised classification. The Normalized Difference Vegetation Index (NDVI), which is also called the greenness index, is used along with the surface reflectance and brightness temperature as the input features. Trainings and classifications are performed for two spatial modes and three multitemporal modes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kiang, RK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 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 0-8194-2700-4 J9 P SOC PHOTO-OPT INS PY 1998 VL 3261 BP 299 EP 304 DI 10.1117/12.310564 PG 6 WC Engineering, Biomedical; Microscopy; Optics; Spectroscopy SC Engineering; Microscopy; Optics; Spectroscopy GA BL26U UT WOS:000074939600033 ER PT S AU Montgomery, K Heyenga, G AF Montgomery, K Heyenga, G BE Ellson, RN Nurre, JH TI Gel tomography for 3D acquisition of plant root systems SO THREE-DIMENSIONAL IMAGE CAPTURE AND APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Meeting on 3-Dimensional Image Capture and Applications CY JAN 27-28, 1998 CL SAN JOSE, CA SP SPIE Int Soc Opt Engn, IS&T Soc Imaging Sci & Technol AB A system for three-dimensional, non-destructive acquisition of the structure of plant root systems is described. The plants are grown in a transparent medium (a "gel pack") and are then placed on a rotating stage. The stage is rotated in 5-degree increments while images are captured using either traditional photography or a CCD camera. The individual images are then used as input to a tomographic (backprojection) algorithm to recover the original volumetric data. This reconstructed volume is then used as input to a 3D-reconstruction system. The software performs segmentation and mesh generation to derive a tessellated mesh of the root structure. This mesh can then be visualized using computer graphics, or used to derive measurements of root thickness and length. For initial validation studies, a wire model of known length and gauge was used as a calibration sample. The use of the transparent gel-pack media, together with the gel tomography software, allows the plant biologist a method for non-destructive visualization and measurement of root structure that has previously been unattainable. C1 NASA, Ames Res Ctr, Biocomputat Ctr, Moffett Field, CA 94035 USA. RP Montgomery, K (reprint author), NASA, Ames Res Ctr, Biocomputat Ctr, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 2 U1 0 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 0-8194-2753-5 J9 P SOC PHOTO-OPT INS PY 1998 VL 3313 BP 102 EP 104 DI 10.1117/12.302442 PG 3 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BK71M UT WOS:000073193100011 ER PT S AU Belegradek, B Kalpakis, K Yesha, Y AF Belegradek, B Kalpakis, K Yesha, Y BE Lamersdorf, W Merz, M TI Maximizing seller's profit for electronic commerce SO TRENDS IN DISTRIBUTED SYSTEMS FOR ELECTRONIC COMMERCE SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Article; Proceedings Paper CT International IFIP/GI Working Conference on Trends in Distributed Systems for Electronic Commerce (TREC 98) CY JUN 03-05, 1998 CL HAMBURG, GERMANY SP Int Federat Informat Proc, Gesell Informat DE pricing strategies; market models; electronic commerce; computational learning theory; dynamic programming; search trees; discrete algorithms ID DURABLE GOODS MONOPOLY; UNCERTAINTY AB Suppose there is a seller that has an unlimited number of units of a single product for sale. The seller at each moment of time posts a price for his/her product. Based of the posted price, at each moment of time, a buyer decides whether or not to buy a unit of that product from the seller. The only information about the buyer to the seller is the seller's sales history. Further, we assume that the maximal unit price the buyer is willing to pay does not change over time. The question then is how should the seller price his/her product to maximize profits? To address this question, we use the notion of loss functions. Intuitively, a loss function is a measure, at each moment of time, of the lost opportunity to make a profit. In particular, we provide a polynomial-time algorithm that finds a pricing algorithm (strategy) for the seller that minimizes the average (total) losses over time. Further, we present preliminary results on pricing strategies that minimize the maximum possible loss at every moment of time. We also show that there is no strategy minimizing both the total loss and the maximum loss at the same time. C1 Univ Maryland Baltimore Cty, Dept Comp Sci & Elect Engn, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Ctr Excellence Space Data & Informat Sci, Greenbelt, MD 20771 USA. RP Belegradek, B (reprint author), Univ Maryland Baltimore Cty, Dept Comp Sci & Elect Engn, 1000 Hilltop Circle, Baltimore, MD 21250 USA. NR 13 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 3-540-64564-0 J9 LECT NOTES COMPUT SC PY 1998 VL 1402 BP 26 EP 38 PG 13 WC Computer Science, Information Systems; Computer Science, Theory & Methods SC Computer Science GA BM58S UT WOS:000079185700003 ER PT J AU Miyoshi, K Murakawa, M Watanabe, S Takeuchi, S Miyake, S Wu, RLC AF Miyoshi, K Murakawa, M Watanabe, S Takeuchi, S Miyake, S Wu, RLC TI CVD diamond, DLC, and c-BN coatings for solid film lubrication SO TRIBOLOGY LETTERS LA English DT Article; Proceedings Paper CT Symposium on Synthesis, Characterization and Applications of Hard Coatings CY JUN, 1997 CL NORTHWESTERN UNIV, EVANSTON, IL SP Amer Soc Mech Engineers, Amer Soc Civil Engineers, Soc Engn Sci HO NORTHWESTERN UNIV DE solid film lubrication; superhard coatings; DLC; CVD diamond; c-BN ID CARBON; FRICTION; WEAR AB The main criteria for judging coating performance were coefficient of friction and wear rate, which had to be less than 0.1 and 10(-6) mm(3)/(N.m), respectively. Carbon- and nitrogen-ion-implanted, fine-grain, chemical-vapor-deposited (CVD) diamond and diamondlike carbon (DLC) ion beam deposited on fine-grain CVD diamond met the criteria regardless of environment (vacuum, nitrogen, and air). C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. K Syst Corp, Beavercreek, OH 45431 USA. RP Miyoshi, K (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 19 TC 18 Z9 19 U1 0 U2 5 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PY 1998 VL 5 IS 2-3 BP 123 EP 129 DI 10.1023/A:1019133406413 PG 7 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 122LN UT WOS:000076073200002 ER PT J AU Chang, L Hall, PB Thom, R AF Chang, L Hall, PB Thom, R TI Scuffing characteristics of high-load rolling/sliding contacts operating in liquid oxygen - Effects of materials and surface roughness SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 51st Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 19-23, 1996 CL CINCINNATI, OHIO SP Soc Tribologists & Lubricat Engineers DE scuffing; materials, properties and tribology; surface roughness; cryogenic lubricants AB This research reports on an experimental study of the effects of materials and surface roughness on the scuffing characteristics of rolling/sliding contacts cooled and lubricated with liquid oxygen. Experiments were carried out under heavy loading with a Hertzian pressure in the range of 2.0 to 3.0 GPa and with a high rolling velocity of up to 48 m/s. For contacts between AISI 440C stainless-steel elements, the results showed that the scuffing behavior of the system was fairly consistent under a wide range of rolling velocity. Scuffing commenced at a small slide-to-roll ratio of around 0.02, and the scuffing behavior of the contact was not sensitive to surface roughness for the lest-sample RMS roughness ranging from 0.02 to 0.10 mu m. For contacts between 440C and Si3N4 elements, on the other hand, the scuffing behavior of the system was not very consistent and was somewhat unpredictable The results were sensitive to surface roughness, particularly that of the Si3N4 test sample. With well-polished test samples, consistent results were obtained; the level of traction was lower than that with a 440C toroid and scuffing did not take place up to a slide-to-roll ratio of near 0.03. The results strongly suggest that significant hydrodynamic effect can be generated by liquid oxygen under heavy loading and high velocity conditions. The results also suggest that the hydrodynamic action is likely generated by the conventional viscous mechanism as it can be largely destroyed by a narrow circumferential surface scratch running through the central region of the contact. C1 Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NASA, George C Marshall Space Flight Ctr, Tribol Res Branch, Huntsville, AL 35812 USA. RP Chang, L (reprint author), Penn State Univ, Dept Mech Engn, University Pk, PA 16802 USA. NR 9 TC 2 Z9 4 U1 0 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JAN PY 1998 VL 41 IS 1 BP 87 EP 95 DI 10.1080/10402009808983725 PG 9 WC Engineering, Mechanical SC Engineering GA YW245 UT WOS:000071913000011 ER PT B AU Vander Wal, RL AF Vander Wal, RL BE Burgess, AR Dryer, FL TI Calibration and comparison of laser-induced incandescence with cavity ring-down SO TWENTY-SEVENTH SYMPOSIUM (INTERNATIONAL) ON COMBUSTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 27th International Symposium on Combustion CY AUG 02-07, 1998 CL UNIV COLORADO, BOULDER, CO SP Combust Inst, Aerometr Inc, Air Force Off Sci Res, Army Res Off, Arthur D Little, Chevron Res & Technol Co, CONSOL Inc, Elsevier Sci Inc, ENERGIA Inc, Engn Management Consultants, EXXON Res & Engn Co, Ford Motor Co, Gas Res Inst, Gen Elect R & D Ctr, Gordon & Breach Publishers Inc, NASA, Natl Inst Stand & Technol, Owens Brockway Glass Containers, Phillip Morris Corp, PPG Industries Inc, React Engn Int, Res Ind Inc, Sandia Natl Labs, Sawyer Associates, United Technol Res Ctr HO UNIV COLORADO ID SOOT-VOLUME FRACTION; ABSORPTION SPECTROSCOPY; FLICKERING METHANE; DIFFUSION FLAMES; MORPHOLOGY; HISTORY; LII AB Laser-induced incandescence (LII), a technique that determines relative soot volume fraction: requires calibration to achieve quantitative results. Although not spatially resolved, cavity ring-down (CRD), an absorption-based method, provides an integrated measure of f(v) along the line-of sight. Here, spatially resolved LII signals from soot within a methane/air diffusion flame are calibrated using CRD, which avoids extrapolation required of less sensitive methods in current use. Comparison of CRD with traditional light extinction and path-integrated LII verifies its accuracy for f(v) determination. Using CRD, quantification of LII for parts per billion (ppb) f(v) levels is demonstrated. Experimental tests demonstrate the accuracy of CRD for a single laser-pulse to be better than +/- 5% for measurement of ppb soot volume fraction levels over a l-cm pathlength. Using calibrated detector characteristics and a predetermined f(v) level, the absolute LII signal level within a detection bandwidth of 405-415 nm produced by a laser fluence of 0.25 J/cm(2) at 1064 nm within a laminar ethylene/air diffusion flame was calculated. This value is 5 x 10(5) photons/srnm per ppm of soot, collected over a 10-ns interval centered at the peak of the LII signal. Comparison of LII with CRD reveals that CRD may be used to advantage in applications where spatially resolved information is not necessary and/or achieving high geometric collection efficiency is impractical. LII's chief advantages are the spatially resolved f(v) visualization and geometric versatility. C1 NASA, Lewis Res Ctr, NCMR, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA, Lewis Res Ctr, NCMR, M-S-110-3,2100 Brookpark Rd, Cleveland, OH 44135 USA. NR 30 TC 2 Z9 2 U1 0 U2 1 PU COMBUSTION INSTITUTE PI PITTSBURGH PA 5001 BAUM BLVD, SUITE 635, PITTSBURGH, PA 15213-1851 USA PY 1998 BP 59 EP 67 PG 5 WC Thermodynamics; Chemistry, Applied; Engineering, Multidisciplinary SC Thermodynamics; Chemistry; Engineering GA BN87V UT WOS:000083308600004 ER PT B AU Miller, RS Bellan, J AF Miller, RS Bellan, J BE Burgess, AR Dryer, FL TI On the validity of the assumed probability density function method for modeling binary mixing/reaction of evaporated vapor in gas/liquid-droplet turbulent shear flow SO TWENTY-SEVENTH SYMPOSIUM (INTERNATIONAL) ON COMBUSTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 27th International Symposium on Combustion CY AUG 02-07, 1998 CL UNIV COLORADO, BOULDER, CO SP Combust Inst, Aerometr Inc, Air Force Off Sci Res, Army Res Off, Arthur D Little, Chevron Res & Technol Co, CONSOL Inc, Elsevier Sci Inc, ENERGIA Inc, Engn Management Consultants, EXXON Res & Engn Co, Ford Motor Co, Gas Res Inst, Gen Elect R & D Ctr, Gordon & Breach Publishers Inc, NASA, Natl Inst Stand & Technol, Owens Brockway Glass Containers, Phillip Morris Corp, PPG Industries Inc, React Engn Int, Res Ind Inc, Sandia Natl Labs, Sawyer Associates, United Technol Res Ctr HO UNIV COLORADO ID SIMULATIONS; LAYER AB An investigation of the statistical description of binary mixing and/or reaction between a carrier gas and an evaporated vapor species in two-phase gas-liquid turbulent flows is performed through both theoretical analysis and comparisons with results from direct numerical simulations (DNS) of a two-phase mixing layer. In particular, the validity and added complications of extending single-point assumed probability density function (PDF) methods to two-phase flows involving evaporating droplets as sources of vapor are addressed. Noting that Favre density-weighted averaging is the most convenient form for moment transport equations for these flows, algebraic relationships are derived for the ratios of the Favre and nonweighted scalar means and variances. Comparisons with the DNS results indicate that the mixture fraction Favre moments are nearly identical to the corresponding nonweighted moments even at the mixing layer centerline where the root mean square (rms) density fluctuation is >12% of the mean density. It is therefore considered appropriate to use Favre moments for the nonweighted PDF closure. A transport equation for the Favre mixture fraction variance is then presented that contains four new terms due to evaporation effects. The DNS results indicate that one of these terms due to scalar-source correlations is predominantly responsible for scalar variance production, whereas the remaining three terms are of negligible magnitude. Finally, the beta PDF, which is known to represent well the DNS generated mixture fraction statistics for single-phase mixing, is shown to be a poor representation for mixing of vapor resulting from droplet evaporation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Miller, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 1 U2 2 PU COMBUSTION INSTITUTE PI PITTSBURGH PA 5001 BAUM BLVD, SUITE 635, PITTSBURGH, PA 15213-1851 USA PY 1998 BP 1065 EP 1072 PG 4 WC Thermodynamics; Chemistry, Applied; Engineering, Multidisciplinary SC Thermodynamics; Chemistry; Engineering GA BN87V UT WOS:000083308600121 ER PT B AU Olson, SL Baum, HR Kashiwagi, T AF Olson, SL Baum, HR Kashiwagi, T BE Burgess, AR Dryer, FL TI Finger-like smoldering over thin cellulosic sheets in microgravity SO TWENTY-SEVENTH SYMPOSIUM (INTERNATIONAL) ON COMBUSTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 27th International Symposium on Combustion CY AUG 02-07, 1998 CL UNIV COLORADO, BOULDER, CO SP Combust Inst, Aerometr Inc, Air Force Off Sci Res, Army Res Off, Arthur D Little, Chevron Res & Technol Co, CONSOL Inc, Elsevier Sci Inc, ENERGIA Inc, Engn Management Consultants, EXXON Res & Engn Co, Ford Motor Co, Gas Res Inst, Gen Elect R & D Ctr, Gordon & Breach Publishers Inc, NASA, Natl Inst Stand & Technol, Owens Brockway Glass Containers, Phillip Morris Corp, PPG Industries Inc, React Engn Int, Res Ind Inc, Sandia Natl Labs, Sawyer Associates, United Technol Res Ctr HO UNIV COLORADO ID FLAME SPREAD AB Microgravity smolder spread over a thin cellulosic fuel was studied with the Radiative Ignition and transition to Spread Investigation (RITSI) apparatus in the Glovebox Facility on the STS-75 USMP-5 space shuttle mission. Radiative smoldering ignition was initiated Ly a focused beam from a tungsten/halogen lamp at the center of the smolder-promoted filter paper. The external airflow velocity was varied from 0.5 cm/s to 6.5 cm/s. The ignition and subsequent smolder spread events were recorded by a video camera. a 35-mm camera. and six thermocouples (two in the gas phase and four in the sample). Nonpiloted smoldering ignition of the paper in microgravity by external thermal radiation was demonstrated for the first time. Unlike the uniform normal gravity smolder front, a complex unexpected finger-shaped char growth pattern was observed in microgravity. The preferred direction of smolder finger propagation was upstream into the fresh oxidizer. Downstream smolder was less viable and slower. Increasing external flow velocity increased the number of localized smoldering fronts, the number of the char fingers they left behind, and the frequency of bifurcations from the fingers, in analytical "oxygen shadow" model indicated that each localized smolder front cast an oxygen shadow that depleted the ambient oxygen in an egg-shaped legion al around itself These oxygen shadows ale a plausible explanation of the fingering smolder patterns observed in the experiments. C1 NASA, Lewis Res Ctr, Micrograv Combust Sci Branch, Cleveland, OH 44135 USA. RP Olson, SL (reprint author), NASA, Lewis Res Ctr, Micrograv Combust Sci Branch, Cleveland, OH 44135 USA. NR 10 TC 7 Z9 7 U1 0 U2 0 PU COMBUSTION INSTITUTE PI PITTSBURGH PA 5001 BAUM BLVD, SUITE 635, PITTSBURGH, PA 15213-1851 USA PY 1998 BP 2525 EP 2533 PG 5 WC Thermodynamics; Chemistry, Applied; Engineering, Multidisciplinary SC Thermodynamics; Chemistry; Engineering GA BN87V UT WOS:000083308600290 ER PT B AU Ross, HD Miller, FJ AF Ross, HD Miller, FJ BE Burgess, AR Dryer, FL TI Flame spread across liquid pools with very low-speed opposed or concurrent airflow SO TWENTY-SEVENTH SYMPOSIUM (INTERNATIONAL) ON COMBUSTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 27th International Symposium on Combustion CY AUG 02-07, 1998 CL UNIV COLORADO, BOULDER, CO SP Combust Inst, Aerometr Inc, Air Force Off Sci Res, Army Res Off, Arthur D Little, Chevron Res & Technol Co, CONSOL Inc, Elsevier Sci Inc, ENERGIA Inc, Engn Management Consultants, EXXON Res & Engn Co, Ford Motor Co, Gas Res Inst, Gen Elect R & D Ctr, Gordon & Breach Publishers Inc, NASA, Natl Inst Stand & Technol, Owens Brockway Glass Containers, Phillip Morris Corp, PPG Industries Inc, React Engn Int, Res Ind Inc, Sandia Natl Labs, Sawyer Associates, United Technol Res Ctr HO UNIV COLORADO ID FUEL AB The consequences of forced airflow on flame spread over liquids is to a large extent unexplored, especially for low air speeds on the older of that due to buoyant convection driven bw the flame. Yet small gas flows can influence heat and mass transfer ahead of the flame and alter its spreading characteristics. In this paper we present results from normal and microgra\-it?i experiments on flame spread over l-butanol with either an opposed or a co-current Forced. airflow ranging fi om 5 to 30 cm/s. A small flow duct was used to control the air flowing over a laboratory-scale fuel tray. Video flame imaging was used to determine the flame shapes and spread rates, and Rainbow Schlieren Deflectometry (RSD) and infrared thermography of the liquid surface were employed to measure the liquid thermal Fields during spread. Large differences in the liquid temperature field were noted depending on the flow direction, and for some concurrent flow rates, the initial flame spread rate was affected. Slow opposed airflows serve mainly to alter the fame pulsation frequency, while small concurrent flows eliminate the pulsations in agreement with numerical modeling that indicates a gas-phase recirculation cell is necessary for flame pulsations. In microgravity the flame spreads slowly and uniformly for higher opposed velocities, and a lower bound of between 10 and 20 cm/s is found below which the flame begins to spread and then extinguishes. C1 NASA, Lewis Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. RP Ross, HD (reprint author), NASA, Lewis Res Ctr, Micrograv Sci Div, MS 500-115, Cleveland, OH 44135 USA. NR 17 TC 7 Z9 8 U1 0 U2 0 PU COMBUSTION INSTITUTE PI PITTSBURGH PA 5001 BAUM BLVD, SUITE 635, PITTSBURGH, PA 15213-1851 USA PY 1998 BP 2723 EP 2729 PG 3 WC Thermodynamics; Chemistry, Applied; Engineering, Multidisciplinary SC Thermodynamics; Chemistry; Engineering GA BN87V UT WOS:000083308600314 ER PT S AU Barnes, JC AF Barnes, JC BE DiBartolo, B TI NASA's DIAL and lidar laser technology development program SO ULTRAFAST DYNAMICS OF QUANTUM SYSTEMS: PHYSICAL PROCESSES AND SPECTROSCOPIC TECHNIQUES SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES B, PHYSICS LA English DT Proceedings Paper CT NATO Advanced Study Institute on Ultrafast Dynamics of Quantum Systems - Physical Processor and Spectroscopic Techniques CY JUN 15-30, 1997 CL ERICE, ITALY SP NATO, Sci Affairs Div, Boston Coll, ENEA Org, European Phys Soc, Italian Minist Educ, Italian Minist Univ & Sci Res, Sicilian Reg Govt C1 NASA, Langley Res Ctr, Remote Sensing Technol Branch, Hampton, VA 23607 USA. RP Barnes, JC (reprint author), NASA, Langley Res Ctr, Remote Sensing Technol Branch, Mail Stop 474, Hampton, VA 23607 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0258-1221 BN 0-306-45929-9 J9 NATO ADV SCI I B-PHY PY 1998 VL 372 BP 545 EP 552 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Spectroscopy SC Engineering; Optics; Physics; Spectroscopy GA BM25K UT WOS:000078179700018 ER PT S AU Walsh, BM AF Walsh, BM BE DiBartolo, B TI 0.94 mu m spectroscopy and laser development SO ULTRAFAST DYNAMICS OF QUANTUM SYSTEMS: PHYSICAL PROCESSES AND SPECTROSCOPIC TECHNIQUES SE NATO ADVANCED SCIENCE INSTITUTES SERIES, SERIES B, PHYSICS LA English DT Proceedings Paper CT NATO Advanced Study Institute on Ultrafast Dynamics of Quantum Systems - Physical Processor and Spectroscopic Techniques CY JUN 15-30, 1997 CL ERICE, ITALY SP NATO, Sci Affairs Div, Boston Coll, ENEA Org, European Phys Soc, Italian Minist Educ, Italian Minist Univ & Sci Res, Sicilian Reg Govt C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Walsh, BM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PRESS DIV PLENUM PUBLISHING CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0258-1221 BN 0-306-45929-9 J9 NATO ADV SCI I B-PHY PY 1998 VL 372 BP 701 EP 702 PG 2 WC Engineering, Electrical & Electronic; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Spectroscopy SC Engineering; Optics; Physics; Spectroscopy GA BM25K UT WOS:000078179700052 ER PT S AU Biegel, BA AF Biegel, BA BE Tsen, KT Fetterman, HR TI Wigner function simulation of intrinsic oscillations, hysteresis, and bistability in resonant tunneling structures SO ULTRAFAST PHENOMENA IN SEMICONDUCTORS II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Ultrafast Phenomena in Semiconductors II CY JAN 28-29, 1998 CL SAN JOSE, CA SP Soc Photo Opt Instrumentat Engineers DE Wigner function simulation; resonant tunneling diodes; self-oscillation; bistability; hysteresis AB Several interesting behaviors of resonant tunneling diodes (RTDs) are investigated through numerical simulation: high frequency self-oscillations, strong intrinsic hysteresis, and pronounced static bistability. Each of these behaviors has been observed experimentally in RTDs, but the measured effects have been slower (oscillations), weaker (hysteresis, bistability), or required external inductance to occur (oscillations, hysteresis). These simulations indicate that the effects occur strongly and intrinsically in an RTD when a narrow energy band in the emitter aligns just below a quantized energy state in the quantum well. Quantum system models and available computation power have only recently developed to a point where the necessary physical effects (inelastic scattering, self-consistency, and transient operation) can be properly included to simulate these behaviors in a quantum device. A 1-D Wigner function model is used for transient, self-consistent RTD simulations including inelastic scattering. 1-D transfer-matrix calculations are used to locate quantized energy levels. The physics behind the intrinsic oscillations, hysteresis, and bistability are described for the simulated RTD. Simulation results are also presented for double-well RTD structures in an attempt to enhance these effects. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Biegel, BA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 1 Z9 1 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 0-8194-2716-0 J9 P SOC PHOTO-OPT INS PY 1998 VL 3277 BP 159 EP 169 DI 10.1117/12.306152 PG 11 WC Engineering, Electrical & Electronic; Optics; Physics, Condensed Matter SC Engineering; Optics; Physics GA BL12Z UT WOS:000074381700019 ER PT S AU Agee, CB AF Agee, CB BE Hemley, RJ TI Phase transformations and seismic structure in the upper mantle and transition zone SO ULTRAHIGH-PRESSURE MINERALOGY: PHYSICS AND CHEMISTRY OF THE EARTH'S DEEP INTERIOR SE REVIEWS IN MINERALOGY LA English DT Article; Proceedings Paper CT Short Course on Ulltrahigh-Pressure Mineralogy - Physics and Chemistry of the Earths Deep Interior CY DEC 04-06, 1998 CL UNIV CALIFORNIA DAVIS, DAVIS, CALIFORNIA SP Mineralog Soc Amer HO UNIV CALIFORNIA DAVIS ID X-RAY-DIFFRACTION; CRYSTAL ELASTIC PROPERTIES; SYSTEM MG2SIO4-FE2SIO4; MODIFIED SPINEL; PERIDOTITE KLB-1; 16.5 GPA; HIGH-P; DISCONTINUITY; FORSTERITE; OLIVINE C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Agee, CB (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 87 TC 48 Z9 55 U1 3 U2 11 PU MINERALOGICAL SOC AMERICA PI WASHINGTON PA 1015 EIGHTEENTH ST, NW, SUITE 601, WASHINGTON, DC 20036-5274 USA SN 0275-0279 BN 0-939950-48-0 J9 REV MINERAL PY 1998 VL 37 BP 165 EP 203 PG 39 WC Mineralogy SC Mineralogy GA BM10M UT WOS:000077643800005 ER PT S AU Kondo, Y AF Kondo, Y BE Wamsteker, WQ Riestra, RG Harris, B TI Space astronomy and IUE SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kondo, Y (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 5 EP 6 PG 2 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300001 ER PT S AU Kallman, T AF Kallman, T BE Wamsteker, WQ Riestra, RG Harris, B TI High mass X-ray binaries as seen in the UV SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council AB High mass X-ray binary systems consist of a collapsed star, such as a neutron star or black hole, in orbit with an O or B star. X-rays are produced as gas from the normal star is accreted onto the compact object with the conversion of gravitational potential energy into radiation. Depending on the intensity of the X-rays relative to the wind from the primary star, the X-ray source can have a variety of effects which are observable in the UV. These will be reviewed in this talk, along with some recent theoretical models for these systems. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kallman, T (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 395 EP 400 PG 6 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300067 ER PT S AU Pun, CSJ Sonneborn, G Fransson, C Kirshner, RP AF Pun, CSJ Sonneborn, G Fransson, C Kirshner, RP BE Wamsteker, WQ Riestra, RG Harris, B TI Ultraviolet observations of SN 1987A with IUE and HST SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council DE supernovae, individual (SN 1987A); supernova remnants; circumstellar matter; ultraviolet spectroscopy AB The first five years of IUE data of SN 1987A (1987.2 - 1992.5) have been re-analyzed to generate a complete catalog of the continuum emission from the supernova debris and the narrow high-temperature emission lines from the circumstellar gas. Special attention is paid on the correct subtraction of the flux from the neighboring stars in the aperture. The bolometric luminosity of SN 1987A is re-calculated to properly include contribution from the UV flux, which becomes increasingly important in late times (at day 800, L(UV)/L(UVOIR) = 0.07). Also, the narrow line data provide improved measurements of the properties of the emitting circumstellar gas, such as size, inclination, and abundance. Efforts to establish a long term evolution of the UV photometry and spectroscopy of the supernova system with IUE and HST are described. Recent far-UV STIS observations (1997.5) of the shock interaction between the high-velocity supernova debris and the circumstellar gas, in the form of a high-velcity (v similar to +/-20,000 km s(-1)) broad Ly alpha emission and a localized 'hot spot' (v less than or equal to 250 km s(-1)), associated with reverse and forward shocks, respectively, are presented. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Pun, CSJ (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 401 EP 410 PG 10 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300068 ER PT S AU Crenshaw, DM Kraemer, SB Filippenko, AV Peterson, BM AF Crenshaw, DM Kraemer, SB Filippenko, AV Peterson, BM BE Wamsteker, WQ Riestra, RG Harris, B TI Ultraviolet and optical spectra of the narrow-line region in NGC 5548 SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council DE Seyfert galaxies; Narrow-Line Region; UV; spectroscopy; NGC 5548 AB UV spectra of the Seyfert 1 galaxy NGC 5548 were obtained with the Faint Object Spectrograph on the Hubble Space Telescope, and calibrated in absolute flux using near-simultaneous spectra from the International Ultraviolet Explorer. The UV spectra were combined with groundbased optical spectra to study the narrow emission lines over the 1200 - 10,000 angstrom region. All of the spectra were obtained when the broad emission line and continuum fluxes were at an historic low level, allowing us to easily identify the contribution of the narrow-line region (NLR) to the emission lines. We have generated multicomponent photoionization models to investigate the relative strength of the high ionization lines, compared to Seyfert 2 galaxies, and the weakness of the narrow Mg II line. We present evidence for a high-ionization component of NLR gas that is very close (similar to 1 pc) to the nucleus, and optically thin to ionizing radiation. We also show that the majority of the emission in the NLR of NGC 5548 must arise within about 70 pc from the nucleus. Thus, the NLR in this Seyfert 1 galaxy is very physically compact compared to the typical NLR in Seyfert 2 galaxies. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crenshaw, DM (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 605 EP 608 PG 4 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300105 ER PT S AU Riegler, G AF Riegler, G BE Wamsteker, WQ Riestra, RG Harris, B TI The International Ultraviolet Explorer final archive SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council AB IUE is an international partnership of ESA, the United Kingdom, and the National Aeronautics and Space Administration (NASA). Based on advice from the outside science community (through NASA's process of convening biennial external science community reviews of its mission operations and science data analysis programs, the "Senior Review" process) in 1994, NASA concentrated on completing IUE operations and preparing the "final archive". All IUE operations were assumed by ESA/VILSPA in 1995. After the end of IUE operations in late 1996, all IUE partners concentrated on completing the data processing and archiving tasks for IUE data. C1 NASA, Off Space Studies, Washington, DC 20546 USA. RP Riegler, G (reprint author), NASA, Off Space Studies, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 687 EP 688 PG 2 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300117 ER PT S AU Oliversen, N Massa, D Lawton, P Van Steenberg, ME AF Oliversen, N Massa, D Lawton, P Van Steenberg, ME BE Wamsteker, WQ Riestra, RG Harris, B TI UV/Optical archive data services of the GSFC's astrophysics data facility (ADF) SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council DE UV/Optical Data Archives; Information Systems AB The Goddard Space Flight Center's (GSFC) Astrophysics Data Facility (ADF), in association with the National Space Science Data Center (NSSDC), archives and distributes Ultraviolet (UV) and Optical Astronomical datasets of primary interest to NASA-supported researchers. An extensive collection of UV and Optical datasets are archived on the NASA Data Archive and Distribution Service (NDADS). In order to make this invaluable data collection more easily accessible to researchers, we have developed several new interfaces to access astrononomical data (both internal and external to the ADF/NSSDC archive) which feature: Science based queries; Quick-look data browsers; Archival data selection and ordering tools; and data delivery tools. The UV and Optical data services of the ADF are described in this paper. C1 NASA, Goddard Space Flight Ctr, Hughes STX & Astrophys Data Facil, Greenbelt, MD 20771 USA. RP Oliversen, N (reprint author), NASA, Goddard Space Flight Ctr, Hughes STX & Astrophys Data Facil, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 727 EP 730 PG 4 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300128 ER PT S AU Kraemer, SB AF Kraemer, SB BE Wamsteker, WQ Riestra, RG Harris, B TI Early results from STIS SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council DE instrumentation AB The Space Telescope Imaging Spectrograph (STIS) instrument was installed into HST in February 1997. The design and operational concept of this imaging spectrograph is described. The power and variety of the STIS scientific capabilities were demonstrated in the set of observations taken during the on-orbit checkout phase. We present a selection of these initial results, including biconical outflow from an active galaxy nucleus and high speed multiple shocks from old supernovae and stellar winds. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kraemer, SB (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 779 EP 782 PG 4 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300138 ER PT S AU Sonneborn, G AF Sonneborn, G BE Wamsteker, WQ Riestra, RG Harris, B TI The far ultraviolet spectroscopic explorer mission SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council DE ultraviolet spectroscopy; space instrumentation AB The Far Ultraviolet Spectroscopic Explorer (FUSE) will provide high-resolution (lambda/Delta lambda>24,000) spectroscopy at far ultraviolet (FUV) wavelengths (905-1195 Angstrom) of many astronomical objects in order to address fundamental questions related to the origin of the universe. FUSE will be launched on a Delta II rocket in late 1998 for a three-year mission. The instrument sensitivity will permit far-UV studies of bright extragalactic sources at high spectral resolution. The key science drivers for the mission design are absorption-line spectroscopy of the ISM and IGM to investigate D/H, O VI, and molecular hydrogen abundances and distribution in the Galaxy and beyond to z similar to 0.3. Approximately half of the observing time will be available to Guest Investigators. The NASA Research Announcement for the first year of FUSE GI proposals mill be released in early 1998 with proposals due three months later. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Sonneborn, G (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Code 681, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 783 EP 788 PG 6 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300139 ER PT S AU Hasan, H AF Hasan, H BE Wamsteker, WQ Riestra, RG Harris, B TI NASA's Ultraviolet and Visible Astrophysics Program SO ULTRAVIOLET ASTROPHYSICS BEYOND THE IUE FINAL ARCHIVE SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Conference on Ultraviolet Astrophysics Beyond the IUE Final Archive CY NOV 11-14, 1997 CL SEVILLE, SPAIN SP European Space Agcy, European Astron Soc, Soc Espanola Astron, NASA, Particle Phys & Astron Res Council C1 NASA Headquarters, Off Space Sci, Washington, DC 20546 USA. RP Hasan, H (reprint author), NASA Headquarters, Off Space Sci, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-652-X J9 ESA SP PUBL PY 1998 VL 413 BP 827 EP 829 PG 3 WC Physics, Applied SC Physics GA BK94P UT WOS:000073921300146 ER PT S AU Deardorff, DG Keeley, LE Uselton, SP AF Deardorff, DG Keeley, LE Uselton, SP BE Erbacher, RF Pang, A TI exVis: A visual analysis tool for wind tunnel data SO VISUAL DATA EXPLORATION AND ANALYSIS V SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Visual Data Exploration and Analysis V CY JAN 26-27, 1998 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, Soc Photo Opt Instrumentat Engineers DE experimental data; interactive analysis; comparative visualization; aerodynamics; image querying AB exVis is a software tool created to support interactive display and analysis of data collected during wind tunnel experiments. It is a result of a continuing project to explore the uses of information technology in improving the effectiveness of aeronautical design professionals. The data analysis goals are accomplished by allowing aerodynamicists to display and query data collected by new data acquisition systems and to create traditional wind tunnel plots from this data by interactively interrogating these images. exVis was built as a collection of distinct modules to allow for rapid prototyping, to foster evolution of capabilities, and to facilitate object reuse within other applications being developed. It was implemented using C++ and Open Inventor, commercially available object-oriented tools. The initial version was composed of three main classes. Two of these modules are autonomous viewer objects intended to display the test images (ImageViewer) and the plots (GraphViewer). The third main class is the Application User Interface (AUI) which manages the passing of data and events between the viewers, as well as providing a user interface to certain features. User feedback was obtained on a regular basis, which allowed for quick revision cycles and appropriately enhanced feature sets. During the development process additional classes were added, including a color map editor and a data set manager. The ImageViewer module was substantially rewritten to add features and to use the data set manager. The use of an object-oriented design was successful in allowing rapid prototyping and easy feature addition. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP Deardorff, DG (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, MS T27A-1, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 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 0-8194-2738-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3298 BP 92 EP 100 DI 10.1117/12.309531 PG 9 WC Computer Science, Information Systems; Computer Science, Software Engineering; Optics SC Computer Science; Optics GA BL16Z UT WOS:000074536500011 ER PT S AU DeLombard, R Hrovat, K Moskowitz, ME McPherson, KM AF DeLombard, R Hrovat, K Moskowitz, ME McPherson, KM BE Park, SK Juday, RD TI Comparison tools for assessing the microgravity environment of space missions, carriers and conditions SO VISUAL INFORMATION PROCESSING VII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Visual Information Processing VII CY APR 13-14, 1998 CL ORLANDO, FL SP SPIE DE microgravity; acceleration; Shuttle mission; Mir space station; histogram; power spectral density AB The microgravity environment of the NASA Shuttles and Russia's Mir space station have been measured by specially designed accelerometer systems. The need for comparisons between different missions, vehicles, conditions, etc. has been addressed by the two new processes described in this paper. The Principal Component Spectral Analysis (PCSA) and Quasi-steady Three-dimensional Histogram (QTH) techniques provide the means to describe the microgravity acceleration environment of a long time span of data on a single plot. As described in this paper, the PCSA and QTH techniques allow both the range and the median of the microgravity environment to be represented graphically on a single page. A variety of operating conditions may be made evident by using PCSA or QTH plots. The PCSA plot can help to distinguish between equipment operating full time or part time, as well as show the variability of the magnitude and/or frequency of an acceleration source. A QTH plot summarizes the magnitude and orientation of the low-frequency acceleration vector. This type of plot can show the microgravity effects of attitude, altitude, venting, etc. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP DeLombard, R (reprint author), NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 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 0-8194-2836-1 J9 P SOC PHOTO-OPT INS PY 1998 VL 3387 BP 394 EP 402 DI 10.1117/12.316431 PG 9 WC Computer Science, Artificial Intelligence; Computer Science, Information Systems; Engineering, Electrical & Electronic; Optics SC Computer Science; Engineering; Optics GA BL57J UT WOS:000075914200039 ER PT B AU Henze, C AF Henze, C BE Ebert, D Rushmeier, H Hagen, H TI Feature detection in linked derived spaces SO VISUALIZATION '98, PROCEEDINGS LA English DT Proceedings Paper CT 9th Annual IEEE Conference on Visualization (VIS 98) CY OCT 18-23, 1998 CL RES TRIANGLE PK, NC SP IEEE Comp Soc Tech Comm Comp Graph, ACM SIGGRAPH DE computational fluid dynamics; feature detection; flow visualization; multivariate visualization; brushing AB This paper describes by example a strategy for plotting and interacting with data in multiple metric spaces. The example system was designed for use with time-varying computational fluid dynamics (CFD) datasets, but the methodology is directly applicable to other types of field data. The central objects embodied by the tool are portraits, which show the data in various coordinate systems, while preserving their spatial connectivity and temporal variability. The coordinates are derived in various ways from the field data, and an important feature is that new and derived portraits can be created interactively. The primary operations supported by the tool are brushing and linking: the user can select a subset of a given portrait, and this subset is highlighted in all portraits. The user can combine highlighted subsets from an arbitrary number of portraits with the usual logical operators, thereby indicating where an arbitrarily complex set of conditions holds. The system is useful for exploratory visualization and feature detection in multivariate data. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, M-S T27A-1, Moffett Field, CA 94035 USA. EM chenze@nas.nasa.gov NR 16 TC 19 Z9 19 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 USA BN 1-58113-106-2 PY 1998 BP 87 EP + DI 10.1109/VISUAL.1998.745289 PG 9 WC Computer Science, Software Engineering SC Computer Science GA BM36W UT WOS:000078506400010 ER PT B AU Kenwright, DN AF Kenwright, DN BE Ebert, D Rushmeier, H Hagen, H TI Automatic detection of open and closed separation and attachment lines SO VISUALIZATION '98, PROCEEDINGS LA English DT Proceedings Paper CT 9th Annual IEEE Conference on Visualization (VIS 98) CY OCT 18-23, 1998 CL RES TRIANGLE PK, NC SP IEEE Comp Soc Tech Comm Comp Graph, ACM SIGGRAPH AB A fully automatic feature detection algorithm is presented that locates, and distinguishes, lines of flow separation and attachment on surfaces in 3-D numerical flow fields. The algorithm is based on concepts from 2-D phase plane analysis of linear vector fields. Unlike prior visualization techniques based on particle tracing or flow topology, the phase plane algorithm detects separation using local analytic tests. Results show that it not only detects the standard closed separation lines but also the illusive open separation lines which are not captured by flow topology methods. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MRJ Technol Solut, Mail Stop T27A-2, Moffett Field, CA 94035 USA. EM davidk@nas.nasa.gov NR 19 TC 21 Z9 22 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 USA BN 1-58113-106-2 PY 1998 BP 151 EP 158 DI 10.1109/VISUAL.1998.745297 PG 8 WC Computer Science, Software Engineering SC Computer Science GA BM36W UT WOS:000078506400018 ER PT B AU Shen, HW AF Shen, HW BE Ebert, D Rushmeier, H Hagen, H TI Isosurface extraction in time-varying fields using a temporal hierarchical index tree SO VISUALIZATION '98, PROCEEDINGS LA English DT Proceedings Paper CT 9th Annual IEEE Conference on Visualization (VIS 98) CY OCT 18-23, 1998 CL RES TRIANGLE PK, NC SP IEEE Comp Soc Tech Comm Comp Graph, ACM SIGGRAPH DE scalar field visualization; volume visualization; isosurface extraction; time-varying fields; marching cubes; span space AB Many high-performance isosurface extraction algorithms have been proposed in the past several years as a result of intensive research efforts. When applying these algorithms to large-scale time-varying fields, the storage overhead incurred from storing the search index often becomes overwhelming. This paper proposes an algorithm for locating isosurface cells in time-varying fields. We devise a new data structure, called Temporal Hierarchical Index Tree, which utilizes the temporal coherence that exists in a time-varying field and adaptively coalesces the cells' extreme values over time; the resulting extreme values are then used to create the isosurface cell search index. For a typical time-varying scalar data set, not only does this temporal hierarchical index tree require much less storage space, but also the amount of I/O required to access the indices from the disk at different time steps is substantially reduced. We illustrate the utility and speed of our algorithm with data from several large-scale time-varying CFD simulations. Our algorithm can achieve more than 80% of disk-space savings when compared with the existing techniques, while the isosurface extraction time is nearly optimal. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MRJ Technol Solut, Mail Stop T27A-2, Moffett Field, CA 94035 USA. EM hwshen@nas.nasa.gov NR 16 TC 21 Z9 22 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 USA BN 1-58113-106-2 PY 1998 BP 159 EP + DI 10.1109/VISUAL.1998.745298 PG 9 WC Computer Science, Software Engineering SC Computer Science GA BM36W UT WOS:000078506400019 ER PT B AU Keely, L Uselton, S AF Keely, L Uselton, S BE Ebert, D Rushmeier, H Hagen, H TI Development of a multi-source visualization prototype SO VISUALIZATION '98, PROCEEDINGS LA English DT Proceedings Paper CT 9th Annual IEEE Conference on Visualization (VIS 98) CY OCT 18-23, 1998 CL RES TRIANGLE PK, NC SP IEEE Comp Soc Tech Comm Comp Graph, ACM SIGGRAPH AB This case study describes the design and development of VISOR (Visual Integration of Simulated and Observed Results), a tool which supports the visualization and analysis of a wide variety of data relevant to aerospace engineering design. Integrating data from such disparate sources is challenging; overcoming the obstacles results in a powerful tool. The process has also been valuable in exposing requirements for the libraries of reusable software tools for visualization and data analysis being developed at NASA Ames. C1 NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. RP Keely, L (reprint author), NASA, Ames Res Ctr, MRJ Technol Solut, Moffett Field, CA 94035 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 USA BN 1-58113-106-2 PY 1998 BP 411 EP + DI 10.1109/VISUAL.1998.745331 PG 5 WC Computer Science, Software Engineering SC Computer Science GA BM36W UT WOS:000078506400052 ER PT B AU Uselton, S Ahrens, J Bethel, W Treinish, L State, A AF Uselton, S Ahrens, J Bethel, W Treinish, L State, A BE Ebert, D Rushmeier, H Hagen, H TI Multi-source data analysis challenges SO VISUALIZATION '98, PROCEEDINGS LA English DT Proceedings Paper CT 9th Annual IEEE Conference on Visualization (VIS 98) CY OCT 18-23, 1998 CL RES TRIANGLE PK, NC SP IEEE Comp Soc Tech Comm Comp Graph, ACM SIGGRAPH C1 NASA, MRJ Technol Solut, Ames, IA USA. RP Uselton, S (reprint author), NASA, MRJ Technol Solut, Ames, IA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036-9998 USA BN 1-58113-106-2 PY 1998 BP 501 EP 504 PG 4 WC Computer Science, Software Engineering SC Computer Science GA BM36W UT WOS:000078506400074 ER PT J AU Klimeck, G Lake, RK Bowen, RC Fernando, CL Frensley, WR AF Klimeck, G Lake, RK Bowen, RC Fernando, CL Frensley, WR TI Resolution of resonances in a general purpose quantum device simulator (NEMO) SO VLSI DESIGN LA English DT Article; Proceedings Paper CT 4th International Workshop on Computational Electronics (IWCE-4) CY OCT 31-NOV 01, 1995 CL TEMPE, ARIZONA SP USA, Army Res Off, Natl Sci Fdn, USN, Off Naval Res, Arizona State Univ DE resonant tunneling; quantum device; numerical integration; grid generation; NEMO AB Electron transport in quantum devices is governed by discrete quantum states due to electron confinement, A crucial requirement for the modeling of quantum devices is the the numerical identification and resolution of these quantum states. We present an algorithm utilized in our general purpose quantum device simulator (NEMO), where we locate the resonances of the system first and then generate the optimized grid used to integrate over the resonances. We find this algorithm important in the modeling of coherent transport involving ultrafine resonances and crucial for the modeling of incoherent transport. C1 Univ Texas, Sch Engn, Richardson, TX 75083 USA. Texas Instruments Inc, Corp R&D, Dallas, TX 75235 USA. RP Klimeck, G (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 6 TC 11 Z9 11 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1065-514X J9 VLSI DES JI VLSI Des. PY 1998 VL 6 IS 1-4 BP 107 EP 110 DI 10.1155/1998/43043 PG 4 WC Computer Science, Hardware & Architecture SC Computer Science GA 110BF UT WOS:000075358800025 ER PT B AU Figueiredo, MA Gloster, C AF Figueiredo, MA Gloster, C BE Braga, ADP Ludermir, TB TI Implementation of a probabilistic neural network for multi-spectral image classification on an FPGA based custom computing machine SO VTH BRAZILIAN SYMPOSIUM ON NEURAL NETWORKS, PROCEEDINGS LA English DT Proceedings Paper CT 5th Brazilian Symposium on Neural Networks CY DEC 09-11, 1998 CL BELO HORIZONT, BRAZIL SP Brazilian Comp Soc, Int Neural Network Soc, Fed Univ Minas Gerais AB ils the demand for higher performance computers for the processing of remote sensing science algorithms increases, the need to investigate new computing paradigms is justified Field Programmable Gate Arrays enable the implementation of algorithms at the hardware gate level, leading to orders of magnitude performance increase over microprocessor based systems. The automatic classification of space borne multispectral images is an example of a computation intensive application that only tends to increase as instruments start to explore hyperspectral capabilities. A probabilistic neural network is used here to classify pixels of a multispectral LANDSAT-2 image. The implementation described utilizes a commercial-off-the-shelf FPGA based custom computing machine. C1 NASA, Goddard Space Flight Ctr, SGT Inc, Greenbelt, MD 20771 USA. RP Figueiredo, MA (reprint author), NASA, Goddard Space Flight Ctr, SGT Inc, Greenbelt, MD 20771 USA. NR 0 TC 6 Z9 6 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 0-8186-8630-8 PY 1998 BP 174 EP 179 DI 10.1109/SBRN.1998.731021 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Interdisciplinary Applications SC Computer Science GA BM17F UT WOS:000077901600032 ER PT B AU Engman, ET AF Engman, ET BE Abt, SR YoungPezeshk, J Watson, CC TI Application of remote sensing for monitoring floods SO WATER RESOURCES ENGINEERING 98, VOLS 1 AND 2 LA English DT Proceedings Paper CT International Water Resources Engineering Conference CY AUG 03-07, 1998 CL MEMPHIS, TN SP Amer Soc Civil Engineers, Water Resources Engn, US Geol Survey, US EPA, Wetlands Div ID MICROWAVE AB Satellite remote sensing with its comprehensive view of large river basins offers an ideal technology for monitoring floods. Just about all regions of the electromagnetic spectrum can be used for this purpose but sensors in the visible/near infrared and Synthetic Aperture Radar (SAR) are the best sites for this purpose. This paper reviews the space-based satellite technology that can be used for flood delineation and monitoring. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Engman, ET (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Code 974, Greenbelt, MD 20771 USA. NR 18 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CIVIL ENGINEERS PI NEW YORK PA UNITED ENGINEERING CENTER, 345 E 47TH ST, NEW YORK, NY 10017-2398 USA BN 0-7844-0359-7 PY 1998 BP 874 EP 879 PG 6 WC Engineering, Civil; Engineering, Mechanical; Water Resources SC Engineering; Water Resources GA BN36H UT WOS:000081713600146 ER PT S AU Neudeck, PG Huang, W Dudley, M Fazi, C AF Neudeck, PG Huang, W Dudley, M Fazi, C BE DenBaars, S Palmour, J Shur, M Spencer, M TI Non-micropipe dislocations in 4H-SiC devices: Electrical properties and device technology implications SO WIDE-BANDGAP SEMICONDUCTORS FOR HIGH POWER, HIGH FREQUENCY AND HIGH TEMPERATURE SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Wide-Bandgap Semiconductors for High Power, High Frequency and High Temperature CY APR 13-15, 1998 CL SAN FRANCISCO, CA SP Mat Res Soc, AIXTRON Inc, Cree Res Inc, EMCORE Corp, Northrop Grumman Sci & Technol Ctr AB It is well-known that SiC wafer quality deficiencies are delaying the realization of outstandingly superior 4H-SiC power electronics. While efforts to date have centered on eradicating micropipes (i.e., hollow core super-screw dislocations with Burgers vectors > 2c), 4H-SiC wafers and epilayers also contain elementary screw dislocations (i.e., Burgers vector = Ic with no hollow core) in densities on the order of thousands per cm(2), nearly 100-fold micropipe densities. While not nearly as detrimental to SiC device performance as micropipes, it has been previously shown that diodes containing elementary screw dislocations exhibit a 5% to 35% reduction in breakdown voltage, higher pre-breakdown reverse leakage current, softer reverse breakdown I-V knee, and concentrated microplasmic breakdown current filaments when measured under DC testing conditions. This paper details the impact of elementary screw dislocations on the experimentally observed reverse-breakdown pulse-failure characteristics of low-voltage (< 250 V) small-area (< 5 x 10(-4) cm(2)) 4H-SiC p(+)n diodes. The presence of elementary screw dislocations did not significantly affect the failure properties of these diodes when subjected to non-adiabatic breakdown-bias pulsewidths ranging from 0.1 mu s to 20 mu s in duration. Diodes with and without elementary screw dislocations exhibited positive temperature coefficient of breakdown voltage and high junction failure power densities well above the failure power densities exhibited by highly reliable silicon power rectifiers. This preliminary result, based on measurements from one wafer of SiC diodes, suggests that highly reliable low-voltage SiC rectifiers may be attainable despite the presence of elementary screw dislocations. C1 NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Neudeck, PG (reprint author), NASA, Lewis Res Ctr, MS 77-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 5 Z9 5 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-418-1 J9 MATER RES SOC SYMP P PY 1998 VL 512 BP 107 EP 112 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Physics, Applied SC Engineering; Materials Science; Physics GA BL88B UT WOS:000077032000016 ER PT S AU Shi, DT Lu, W Chen, H Collins, WE AF Shi, DT Lu, W Chen, H Collins, WE BE DenBaars, S Palmour, J Shur, M Spencer, M TI The effect of thermal annealing of Au contacts on 6H-SiC and 4H-SiC SO WIDE-BANDGAP SEMICONDUCTORS FOR HIGH POWER, HIGH FREQUENCY AND HIGH TEMPERATURE SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Wide-Bandgap Semiconductors for High Power, High Frequency and High Temperature CY APR 13-15, 1998 CL SAN FRANCISCO, CA SP Mat Res Soc, AIXTRON Inc, Cree Res Inc, EMCORE Corp, Northrop Grumman Sci & Technol Ctr AB The annealing effects of gold contacts on SiC single crystal substrates have been investigated using SPM and XPS/AES. Ultra-thin Au films with thicknesses of 30 Angstrom and 150 Angstrom, respectively, were fabricated onto both 4H- and 6H-SiC substrates via rf sputtering. The Au/SiC systems were then undergone a series of annealing with temperatures ranging from 200 degrees C to 400 degrees C. This study reveals that the sputtering system can generally produce a thin film of uniformly distributed nano-meter sized granular particles. The size of the particles increases with both the thickness of the ultra-thin film and annealing temperature. The thicker Au film revealed pin-hole damages after 300 degrees C annealing and severe cracking and spalling after 400 degrees C. However, the thinner Au film only demonstrated the increase of particle sizes. The atomic ratio of gold to silicon in the surface region decreases with the increase of annealing temperature, which indicates the diffusion of gold into silicon carbide. No significant changes of the Schottky barrier heights have been found for Au contacts onto both 6H- and 4H-SiC in the annealing temperature range. After the 400 degrees C annealing, a noticeable SiO2/SiOx peak was unveiled in the XPS spectra. C1 Fisk Univ, NASA, Fisk Ctr Photon Mat & Devices, Nashville, TN 37208 USA. RP Shi, DT (reprint author), Fisk Univ, NASA, Fisk Ctr Photon Mat & Devices, Nashville, TN 37208 USA. NR 0 TC 2 Z9 2 U1 0 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-418-1 J9 MATER RES SOC SYMP P PY 1998 VL 512 BP 375 EP 380 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Materials Science, Coatings & Films; Physics, Applied SC Engineering; Materials Science; Physics GA BL88B UT WOS:000077032000061 ER PT S AU Drinkwater, MR Long, DG AF Drinkwater, MR Long, DG GP ESA ESA TI Seasat, ERS-1/2 and NSCAT scatterometer-observed changes on the large ice sheets SO WORKSHOP ON EMERGING SCATTEROMETER APPLICATIONS - FROM RESEARCH TO OPERATIONS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-Eumetsat Workshop on Emerging Scatterometer Applications - From Research to Operations CY OCT 05-07, 1998 CL NOORDWIJK, NETHERLANDS SP ESA, Eumetsat AB Satellite-borne wind scatterometers are effective tools for monitoring ice sheets, and microwave imaging techniques enable comparison of historic and contemporary scatterometer data in climate change studies. We document scattering characteristics of the Greenland and Antarctic ice sheets using data from the NSCAT, ERS-1/2 and Seasat SASS instruments. C- and Ku-band data enable characterization of frequency- and incidence-angle dependent scattering characteristics, together with regional and seasonal melting delineation. NSCAT-SASS data differences indicate 18 year changes in microwave backscattering coefficient in response to decadal time-scale changes in the spatial patterns of ice sheet accumulation and ablation. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Drinkwater, MR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Long, David/0000-0002-1852-3972; Drinkwater, Mark/0000-0002-9250-3806 NR 15 TC 3 Z9 3 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-696-1 J9 ESA SP PUBL PY 1998 VL 424 BP 91 EP 96 PG 6 WC Engineering, Aerospace; Geosciences, Multidisciplinary; Instruments & Instrumentation; Remote Sensing SC Engineering; Geology; Instruments & Instrumentation; Remote Sensing GA BM86M UT WOS:000079962700015 ER PT S AU Drinkwater, MR Wadhams, P Low, D Liu, X AF Drinkwater, MR Wadhams, P Low, D Liu, X GP ESA ESA TI Interannual variability in Weddell Sea ice from ERS wind scatterometer SO WORKSHOP ON EMERGING SCATTEROMETER APPLICATIONS - FROM RESEARCH TO OPERATIONS SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT Joint ESA-Eumetsat Workshop on Emerging Scatterometer Applications - From Research to Operations CY OCT 05-07, 1998 CL NOORDWIJK, NETHERLANDS SP ESA, Eumetsat ID ANTARCTICA AB ERS-1/2 SAR and Wind Scatterometer data are analyzed together with DMSP SSM/I microwave radiometer data to investigate interannual variability in Weddell Sea ice and summer melt signatures during the period 1992-1997. Simultaneous SAR and Scatterometer images were obtained during a February 1995 cruise of the H.M.S. Endurance and aerial photographs collected for validation of the satellite observations. Accompanying field data are used to illustrate the observed interannual variability, and to validate the first ever field observations of extensive summer melt pending in the Weddell Sea, Antarctica. A preliminary algorithm is designed to detect the occurrence of melting in the Weddell Sea, and the date upon which the surface begins to melt. In contrast to melt, conspicuous, anomalous summer increases in sea-ice backscatter reveal a process unique to Antarctic sea ice, involving surface flooding of perennial ice flees and upward meteoric ice growth. Time series data indicate that flooding is particularly widespread, and that subsequent freeze-up in these regions potentially contributes a significant volume of sea ice to the total mass budget of the Weddell Sea. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Drinkwater, MR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Drinkwater, Mark/0000-0002-9250-3806 NR 9 TC 3 Z9 3 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-696-1 J9 ESA SP PUBL PY 1998 VL 424 BP 119 EP 123 PG 5 WC Engineering, Aerospace; Geosciences, Multidisciplinary; Instruments & Instrumentation; Remote Sensing SC Engineering; Geology; Instruments & Instrumentation; Remote Sensing GA BM86M UT WOS:000079962700020 ER PT S AU Halpern, D AF Halpern, D GP ESA ESA TI Scatterometer winds over the Arabian Sea SO WORKSHOP ON EMERGING SCATTEROMETER APPLICATIONS - FROM RESEARCH TO OPERATIONS SE ESA SPECIAL PUBLICATIONS LA English DT Meeting Abstract CT Joint ESA-Eumetsat Workshop on Emerging Scatterometer Applications - From Research to Operations CY OCT 05-07, 1998 CL NOORDWIJK, NETHERLANDS SP ESA, Eumetsat C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-696-1 J9 ESA SP PUBL PY 1998 VL 424 BP 152 EP 152 PG 1 WC Engineering, Aerospace; Geosciences, Multidisciplinary; Instruments & Instrumentation; Remote Sensing SC Engineering; Geology; Instruments & Instrumentation; Remote Sensing GA BM86M UT WOS:000079962700026 ER PT S AU Liu, WT AF Liu, WT GP ESA ESA TI Applications of scatterometer winds to study El Nino teleconnection and Asian monsoons SO WORKSHOP ON EMERGING SCATTEROMETER APPLICATIONS - FROM RESEARCH TO OPERATIONS SE ESA SPECIAL PUBLICATIONS LA English DT Meeting Abstract CT Joint ESA-Eumetsat Workshop on Emerging Scatterometer Applications - From Research to Operations CY OCT 05-07, 1998 CL NOORDWIJK, NETHERLANDS SP ESA, Eumetsat C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU EUROPEAN SPACE AGENCY PI PARIS PA 8-10 RUE MARIO NIKIS, 75738 PARIS, FRANCE SN 0379-6566 BN 92-9092-696-1 J9 ESA SP PUBL PY 1998 VL 424 BP 159 EP 159 PG 1 WC Engineering, Aerospace; Geosciences, Multidisciplinary; Instruments & Instrumentation; Remote Sensing SC Engineering; Geology; Instruments & Instrumentation; Remote Sensing GA BM86M UT WOS:000079962700030 ER PT S AU Jones, FC AF Jones, FC BE Krizmanic, JF Ormes, JF Streitmatter, RE TI Acceleration of cosmic rays by colliding galaxies SO WORKSHOP ON OBSERVING GIANT COSMIC RAY AIR SHOWERS FROM >10(20) EV PARTICLES FROM SPACE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Observing Giant Cosmic Ray Air Showers from >10(20)eV Particles from Space CY NOV 13-15, 1997 CL COLLEGE PK, MD AB It has been suggested that colliding galaxy pairs could produce cosmic rays with energies greater than or equal to 10(19) electron volts. We investigate such a system to see if such energies are likely. We find that there is a typical scale energy associated with a large moving magnetic field structure that is the same whether it is in the form of a diffusive plasma shock or a more regular field structure with little or no irregularity. This scaling leads to the conclusion that such energies as suggested are unlikely to be produced by colliding galaxies. C1 Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Jones, FC (reprint author), Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-788-X J9 AIP CONF PROC PY 1998 IS 433 BP 37 EP 41 DI 10.1063/1.56125 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BL30A UT WOS:000075033900003 ER PT S AU Streitmatter, RE AF Streitmatter, RE CA OWL Study Collaboration BE Krizmanic, JF Ormes, JF Streitmatter, RE TI Orbiting wide-angle light-collectors (OWL): Observing cosmic rays from space SO WORKSHOP ON OBSERVING GIANT COSMIC RAY AIR SHOWERS FROM >10(20) EV PARTICLES FROM SPACE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Observing Giant Cosmic Ray Air Showers from >10(20)eV Particles from Space CY NOV 13-15, 1997 CL COLLEGE PK, MD AB High statistics observation of the highest energy cosmic rays is needed to extend the present data and resolve the astrophysical question of the origin of these particles. Use of the nitrogen fluorescence technique to make observations from space of the giant air showers induced by these cosmic rays is a promising approach. We consider the technical requirements upon an instrument capable of such measurements. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Streitmatter, RE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-788-X J9 AIP CONF PROC PY 1998 IS 433 BP 95 EP 107 DI 10.1063/1.56149 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BL30A UT WOS:000075033900009 ER PT S AU Bhattacharjee, P AF Bhattacharjee, P BE Krizmanic, JF Ormes, JF Streitmatter, RE TI Ultrahigh energy cosmic rays from topological defects - Cosmic strings, monopoles, necklaces, and all that SO WORKSHOP ON OBSERVING GIANT COSMIC RAY AIR SHOWERS FROM >10(20) EV PARTICLES FROM SPACE SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Observing Giant Cosmic Ray Air Showers from >10(20)eV Particles from Space CY NOV 13-15, 1997 CL COLLEGE PK, MD AB The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 10(20) eV. Some massive particle production processes involving cosmic strings and magnetic monopoles are discussed..We also discuss the implications of results of certain recent numerical simulations of evolution of cosmic strings. These results (which remain to be confirmed by independent simulations) seem to show that massive particle production may be a generic feature of cosmic strings, which would make cosmic strings an inevitable source of extremely high energy cosmic rays with potentially detectable flux. At the same time, cosmic strings are severely constrained by the observed cosmic ray flux above 10(20) eV, if massive particle radiation is the dominant energy loss mechanism for cosmic strings. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Bhattacharjee, P (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 0 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-788-X J9 AIP CONF PROC PY 1998 IS 433 BP 168 EP 195 DI 10.1063/1.56108 PG 28 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA BL30A UT WOS:000075033900015 ER EF