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  • ENERGY PRODUCTION AND CONVERSION  (2,591)
  • ASTRONOMY  (1,733)
  • 1980-1984  (4,324)
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Years
Year
  • 1
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    The High Resolution Spectrograph for the Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2009-11-16
    Description: The High Resoltuion Spectrograph (HRS) in conjunction with the Space Telescope (ST), extends ultraviolet astronomical spectroscopy to higher spectra, spatial, and time resolutions than previously achieved, as well as to fainter and more distant celestial objects. Other significant advances inherent in the instrument are high photometric accuracy and efficient operation via exposure meter control and real time rejection of bad data. These capabilities are provided to accomplish the scientific programs of the HRS investigation definition team, which concern the interstellar medium, stellar winds, and evolutionary aspects of stellar atmosphere studies; the determination of chemical abundances relevant to stellar evolution; the investigation of quasars and Seyfert galaxy nuclei; and the analysis of the atmospheres of solar system objects, including comets.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 76-105
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  • 2
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    High speed, low cost, LEO-thermal-cycling facility (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The design and operations of a low cost, high rate thermal cycling facility designed for LEO conditions is described. Thermal cycling facilities were constructed with various design criteria. Some were designed to duplicate as closely as possible the conditions a cell or module would encounter while in orbit about the Earth. A typical facility to perform this type of cycling was a large vacuum system with liquid nitrogen cooled walls. The cells were heated by an AMO spectrum solar simulator, then a shutter was closed allowing the cells to give up their heat to the cold walls. This system was good at duplicating the orbital conditions but was slow and very costly to operate. Other systems used a gas atmosphere and heated the cells with radiant heat and cooled the cells by moving them into close proximity to a cold plate. The systems greatly increased the cycle times. Other systems moved the heating and cooling atmosphere into and out of the test areas and achieved reasonable cycle rates. All these systems, however, are expensive to operate.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 223-227
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  • 3
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    Panel fabrication utilizing GaAs solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The development of the GaAs solar cells for space applications is described. The activities in the fabrication of GaAs solar panels are outlined. Panels were fabricated while introducing improved quality control, soldering laydown and testing procedures. These panels include LIPS II, San Marco Satellite, and a low concentration panel for Rockwells' evaluation. The panels and their present status are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 205-209
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  • 4
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    Preflight study of San Marco D/L GaAs solar cell panels (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The solar array for the San Marco D/L spacecraft is described and the performance of 4 GaAs solar cell panels are examined. In comparison to the typical Si solar cell panel for San Marco D/L, it is shown that each GaAs solar cell panel provides at least 23 percent more specific power at maximum output and 28 deg C. Also described here, are several measurements that will be made to evaluate the relative performance of Si and GaAs solar cell panels during the San Marco D/L flight.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 176-181
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  • 5
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    Development of GaAs/Si and GaAs/Si monolithic structures for future space solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The results of heteroepitaxial growth of GaAs and GaAlAs directly on Si are presented, and applications to new cell structures are suggested. The novel feature is the elimination of a Ge lattice transition region. This feature not only reduces the cost of substrate preparation, but also makes possible the fabrication of high efficiency monolithic cascade structures. All films to be discussed were grown by organometallic chemical vapor deposition at atmospheric pressure. This process yielded reproducible, large-area films of GaAs, grown directly on Si, that are tightly adherent and smooth, and are characterized by a defect density of 5 x 10(6) power/sq cm. Preliminary studies indicate that GaAlAs can also be grown in this way. A number of promising applications are suggested. Certainly these substrates are ideal for low-weight GaAs space solar ells. For very high efficiency, the absence of Ge makes the technology attractive for GaAlAs/Si monolithic cascades, in which the Si substrates would first be provided with a suitable p/n junction. An evaluation of a three bandgap cascade consisting of appropriately designed GaAlAs/GaAs/Si layers is also presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 128-139
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  • 6
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    Defect studies in one MeV electron irradiated GaAs and in Al/sub x Ga/sub l-x As P-N junction solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Deep level transient spectroscopy reveals that the main electron traps for one-MeV electron irradiated GaAs cells are E9c)-0.31, E(c)-0.90 eV, and the main hole trap is due to the level. Electron trap density was found to vary from 3/tens-trillion ccm for 2/one quadrillion cm 3/3.7 quadrillion cm for 21 sextillion cm electron fluence for electron fluence; a similar result was also obtained for the hole trap density. As for the grown-in defects in the Al(x)Ga(1-x)As p-n junciton cells, only two electron traps with energies of E(c)-0.20 and E(c)-0.34 eV were observed in samples with x = 0.17, and none was found for x 0.05. Auger analysis on the Al(x)Ga(1-x) As window layer of the GaAs solar cell showed a large amount of oxygen and carbon contaminants near the surface of the AlGaAs epilayer. Thermal annealing experiment performed at 250 C for up to 100 min. showed a reduction in the density of both electron traps.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 91-101
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  • 7
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    Model of solar cell proton damage (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A short circuit current (I sub sc) degradation model for gallium arsenide (GaAs) solar cells irradiated by protons from low energy to 100 MeV was developed. This model was found to be satisfactory in predicting the I sub sc degradation of GaAs cells, but not that of silicon (Si) cells. A modification to the aforementioned model that preserves the optical wavelength dependency in the photogeneration of minority carrier pairs was described herein. Spectral Si and GaAs response and I sub sc for the Si and GaAs solar cells were discussed, and also were presented in graph form. The overall predictability of the modified model was deemed to be satisfactory.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 56-62
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  • 8
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    Process in manufacturing high efficiency AlGaAs/GaAs solar cells by MO-CVD (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Manufacturing technology for mass producing high efficiency GaAs solar cells is discussed. A progress using a high throughput MO-CVD reactor to produce high efficiency GaAs solar cells is discussed. Thickness and doping concentration uniformity of metal oxide chemical vapor deposition (MO-CVD) GaAs and AlGaAs layer growth are discussed. In addition, new tooling designs are given which increase the throughput of solar cell processing. To date, 2cm x 2cm AlGaAs/GaAs solar cells with efficiency up to 16.5% were produced. In order to meet throughput goals for mass producing GaAs solar cells, a large MO-CVD system (Cambridge Instrument Model MR-200) with a susceptor which was initially capable of processing 20 wafers (up to 75 mm diameter) during a single growth run was installed. In the MR-200, the sequencing of the gases and the heating power are controlled by a microprocessor-based programmable control console. Hence, operator errors can be reduced, leading to a more reproducible production sequence.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 18-24
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  • 9
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    The PDS-VAX intelligent plate scanning system of Trieste Astronomical Observatory (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: An intelligent subsystem for interfacing a PDS1010A digital microdensitometer to a DEC DR11W DMA 16 bit UNIBUS port in DEC VAX VMS environment was tested. The subsystem employs two MOTOROLA M68000 microprocessors with 128 KB data memory. The PDS primitives and the user defined high level scanning functions and preprocessing modules are loaded from the host computer into two 8 KB RAM memories in the microprocessors using a dedicated PDS control language. The subsystem is planned to employ a nonstandard photomultiplier electronics. Two design schemes were tested: (1) based on three amplifiers of gain 10 cascaded and multiplexed to a 12 bit AD converter, and (2) based on a single amplifier of gain 100 and two 14 bit AD converters.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 175-187
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  • 10
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    Investigation of critical surface degradation effects on coatings and solar cells developed in Germany (S1002) (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Various coatings developed in the FRG (i.e., second-surface mirrors with interference filters with and without conductive layers, conductive layers on solar-cell covers, and selective absorber coatings) have been qualified by accelerated tests under simulated space environment conditions. Experiments with coatings and solar cells have shown, however, that the thermo-optical behavior can differ considerably when performed on the ground and in space because of the great difficulty in simulating the space environment realistically. The objective of this experiment is to qualify these coatings under realistic space environment conditions. In addition, the experiment will provide design criteria, techniques, and test methods to insure control of the combined space and spacecraft environment effects, such as contamination, electrical conductance, and optical degradation, on the coatings. Data to be measured include the temperature of the samples, the electrical resistance of the conductive layers of the samples, the short circuit current of the solar-cell modules, and the deposition of contaminants on the samples (using quartz crystal microbalances (QCM's)).
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 91-93
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  • 11
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    Solar-array-materials passive LDEF experiment (A0171) (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The objective of this experiment is to evaluate the synergistic effects of the space environment on various solar-array materials, including solar cells, cover slips with various antireflectance coatings, adhesive, encapsulants, reflector materials, substrate strength materials, mast and harness materials, structural composites, and thermal control treatments. The experiment is passive and consists of an arrangement of material specimens mounted in a 3-in.-deep peripheral tray. The effects of the space environment on the specimens will be determined by comparison of preflight and postflight measurements of mechanical, electrical, and optical properties.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 86-87
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  • 12
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    On the cause of the flat-spot phenomenon observed in silicon solar cells at low temperatures and low intensities (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A model that explains the flat-spot power loss phenomenon is presented. Evidence suggests that the effect is due to localized metallurgical interactions between the silicon substrate and the contact metallization. These reactions are shown to result in localized regions in which the P-N junction is destroyed and replaced with a metal semiconductor-like interface. The effects of thermal treatment, crystallographic orientation, junction depth, and metallization are shown along with a method of preventing the effect through the suppression of vacancy formation at the free surface of the contact metallization. Data indicating the effectiveness of a TiN diffusion barrier in preventing the effect are also given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 65-70
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  • 13
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    Reflections on the Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The significance of the Space Telescope for the advancement of astronomy and astrophysics is described. The current state of knowledge in astronomy and cosmology is summarized and unanswered questions in those fields discussed. The rapid evolution of modern astronomy and the need for systematic observations are stressed.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 121-134
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  • 14
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    Astrometric observations with the Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Astrometry with the Space Telescope (ST) is performed using one of the fine guidance sensors (FGS). The FGS, which is based on a pair of Koester's prism interferometers, one for each axis, is capable of measuring the position of one object relative to another with an accuracy of 0.002 arcseconds. Astrometric Data Reduction Software (ADRS) available to the astrometric user of ST is described. The kinds of problems the space telescope astrometry team plans to investigate using ST are discussed.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 114-120
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  • 15
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    The wide field/planetary camera (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A wide site of potential astronomical and solar system scientific studies using the wide field planetary camera on space telescope are described. The expected performance of the camera as it approaches final assembly and testing is also detailed.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 28-39
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  • 16
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    European astronomy and the Space Telescope: The Space Telescope European Coordinating Facility (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The role of the European Coordinating Facility is described. European participation in the Space Telescope Science Institute and the relation of Space Telescope to ground-based astronomy in Europe are discussed.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 16-19
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  • 17
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    Spectroscopy in X-ray astronomy (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: Detailed features in cosmic X-ray sources and their associated temporal variation over a wide energy range were studied. Excess emission and absorption at approximately 6 to 7 kiloelectron volts in the spectra of supernova remnants, binary X-ray sources, and clusters of galaxies were observed. A gas scintillation proportional counter (GSPC) will be used as the detector system. In the gas scintillator the principal limitation is due to the statistics of the initial ionization process only.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 18
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    Far ultraviolet astronomy using the FAUST telescope (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: The Far Ultraviolet Space Telescope (FAUST) a compact, wide field-of-view, far ultraviolet instrument designed for astronomical observations of extended and point sources is discussed. The design and application of the instrument are described. The prime objective is to observe faint astronomical sources with sensitivities higher than previously available. Scientific programs will include: (1) a search for ultraviolet stars which are predicted to exist at the stage of evolution prior to the final death of a star; (2) observations of galaxies and quasars; and (3) joint programs with other Spacelab 1 experiments. The secondary objective is to verify the suitability of the Spacelab as a platform for far ultraviolet astronomy: data will be provided on the ultraviolet background levels due to astronomical, terrestrial, and spacecraft generated sources; the levels of contaminants which affect ultraviolet instruments; and the capability of the Orbiter for stable pointing at celestial sources for useful periods of time.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 19
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    NASA solar array flight experiment (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The NASA large flexible solar array space shuttle flight experiment is described. The 32 x 4 m wing is deployed from the shuttle bay, and experiments in electrical output, multiple deployment, and structural dynamics are planned. Both 2 x 4 cm and 5.9 x 5.9 cm cell assemblies on the array blanket are evaluated. Safety/hazards provisions are described, including emergency jettison provisions. Ground testing and hardware fabrication are summarized.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 179-184
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  • 20
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    Large area low-cost space solar cell development (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A development program to produce 5.9 x 5.9 cm space quality silicon solar cells with a cost goal of 30 $/W is described. Cell types investigated include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm/cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover glass simultaneously is being developed. Results for cell and array tests are given. Large solar arrays that might use cells of this type are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 23-26
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  • 21
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    The swing to concentrator arrays (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Objectives and progress in both low concentration ratio (6 to 10) and high concentration ratio ( 100) array developments are summarized. Problems encountered include: thermal control, maldistribution of concentrated sunlight, current busing, and optical surface degradation. The potential advantages over planar arrays are an order of magnitude reduction in per unit cost of power plus increased immunity to radiation damage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p xix-xxiv
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  • 22
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    The High Speed Photometer for the Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: An overview of the high speed photometer (HSP), its optics and detectors, its electronics, its mechanical structure, and some observational considerations are presented. The capabilities and limitations of the HSP are outlined.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 106-113
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  • 23
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    The Faint Object Camera (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Faint Object Camera fully exploits the spatial resolution capability of the Space Telescope on the very faintest detectable objects over a broad wavelength range. A full complement of filters, objective prisms and polarizers, a choice of coronograhic masks, and a variety of scan formats extend the scientific versatility of the direct imaging mode. In addition, the Faint Object Camera provides the unique facility of long-slit spectroscopy to Space Telescope observers.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 40-54
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  • 24
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    Low concentration ratio solar array structural configuration (1984)
    In:  CASI
    Details
    Publication Date: 2006-04-03
    Description: The design and structural properties of a low concentration ratio solar array are discussed. The assembled module consists of six interconnected containers which are compactly stowed in a volume of 3.24 m(3) for delivery to orbit by the shuttle. The containers deploy in accordian fashion into a rectangular area of 19.4 x 68 meters and can be attached to the user spacecraft along the longitudinal centerline of the end container housing. Five rotary incremental actuators requiring about 8 watts each will execute the 180-degree rotation at each joint. Deployable masts (three per side) are used to extend endcaps from the housing in both directions. Each direction is extended by three masts requiring about 780 watts for about 27 minutes. Concentrator elements are extended by the endcaps and are supported by cable systems that are connected between the housings and endcaps. These power generating elements contain reflector panels which concentrate light onto the solar panels consisting of an aluminum radiator with solar cells positioned within the element base formed by the reflectors. A flat wire harness collects the power output of individual elements for transfer to the module container housing harnesses.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center STEP Expt. Requirements; p 185-198
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  • 25
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    Astronomical capabilities of the Faint Object Spectrograph on Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Examples of scientific observing programs planned with the Faint Object Spectrograph on Space Telescope are presented. An overview of the spectrograph design and operation is presented. The expected astronomical performance of the instrument is described in some detail.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 55-75
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  • 26
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    The Space Telescope Observatory (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The history of the observatory is briefly described, as is the overall system design. The principal design features that are important to the scientific user are described. The present status of preparation for launch in the spring of 1985 is summarized.
    Keywords: ASTRONOMY
    Type: Space Telescope Science Inst. The Space Telescope Obs.; p 20-27
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  • 27
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    STEP flight experiments Large Deployable Reflector (LDR) telescope (1984)
    In:  CASI
    Details
    Publication Date: 2006-04-03
    Description: Flight testing plans for a large deployable infrared reflector telescope to be tested on a space platform are discussed. Subsystem parts, subassemblies, and whole assemblies are discussed. Assurance of operational deployability, rigidization, alignment, and serviceability will be sought.
    Keywords: ASTRONOMY
    Type: NASA. Langley Research Center STEP Expt. Requirements; p 257-278
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  • 28
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    High-efficiency Conventional Cells Workshop (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Participants expressed more interest in GaAs cells than in Si cells. For silicon cells, the beginning of life efficiency is not a major problem but more research is needed in the end of life efficiency. The beginning of life efficiency of GaAs cells must be brought up to 20% at AMO. More proton damage tests must be conducted. Liquid phase epitaxy technology is current but chemical vapor deposition technology is more flexible. There are no obvious problems in limiting process yields. Technology transfer should occur when market demands are generated.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 251-252
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  • 29
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    Transparent arrays: Progress toward higher efficiency (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Principles and design considerations of IR transparent solar arrays are discussed. Optimization of performance of flexible solar arrays was studied. Measured solar absorptance as low as alpha s = 0.59 was achieved which leads to a predicted BOL power density of 182.7 = W/square meters. Advanced array concepts, system level cascaded panels, and transparent rigid panels are proposed and expected benefits discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 210-219
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  • 30
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    Development and support structures for high-power solar arrays (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A number of structurally efficient configurations for wing-type solar arrays are developed by a combination of deepening the planform of the blanket and structure and by partitioning the blanket with battens and frequent attachments to the support structure. This technique reduces the tension required to avoid a low natural frequency for the blanket, and the load reduction results in a lighter structure. The use of three different structures are investigated: the Astromast, the Extendible Support Structure (ESS), and a new beam called the STACBEAM (Stacking Triangular Articulated Compact Beam) and their relative performances are compared. The investigation of the STACBEAM is emphasized because its sequential deployment is more reliable for very long systems, and its linear deployment facilitates local attachments to the blanket and the development of a low mass deployer.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 193-204
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  • 31
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    Preliminary space station solar array structural design study (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 182-192
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  • 32
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    Preliminary concept of a 100-kilowatt miniaturized Cassegrainian concentrator solar array (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A miniaturized Cassegrainian concentrator (MCC) solar array system is examined to assess the practicality of assembling the basic MCC element into a total array system capable of producing multi-hundred kilowatts of power for Space Platform/Space Station or other low Earth orbit long lifetime missions. Preliminary mechanical and electrical subsystems are developed in order to determine first order performance characteristics. Results of the study support the feasibility of a 100-kilowatt MCC array system with beginning-of-life (BOL) performance of 160 watts per square meter and 28 W/kg. The performance numbers are based on 20 percent efficient (at operating temperature) solar cells and 0.25-millimeter thick electroformed nickel optics. These performance numbers can be improved upon significantly with the development of higher efficiency solar cells and/or lighter weight optics.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 157-162
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  • 33
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    High-efficiency solar cells fabricated by vacuum MO-CVD (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: High-efficiency, monolithic, two-color, three-terminal solar cells were fabricated by a novel growth technique, vacuum metal-organic chemical vapor deposition. The technique uses the expensive metal alkyls efficiently and toxic gases sparingly. The fact that the outer chamber is constructed of nonbreakable stainless steel is an attractive safety feature associated with this deposition system.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 148-154
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  • 34
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    Optimal design of high-efficiency single-junction and tandem concentrator space cells at 80 deg C and 100 SUNS (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Computer analysis was used to determine the AMO conversion efficiency of single-junction crystalline cells, two-cell and three-cell crystalline tandem structures operating under 100 suns and at 80 C. For optimally designed devices, the calculated efficiencies are 24% for single-junction cells, 33 to 35% for two-cell tandem structures, and 37 to 39% for three-cell tandem structures. Practical efficiencies are expected to be about 15 relative percentage points lower in each case.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 120-127
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  • 35
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    Equivalent electron fluence for solar proton damage in GaAs shallow junction cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The short-circuit current reduction in GaAs shallow junction heteroface solar cells was calculated according to a simplified solar cell damage model in which the nonuniformity of the damage as a function of penetration depth is treated explicitly. Although the equivalent electron fluence was not uniquely defined for low-energy monoenergetic proton exposure, an equivalent electron fluence is found for proton spectra characteristic of the space environment. The equivalent electron fluence ratio was calculated for a typical large solar flare event for which the proton spectrum is PHI(sub p)(E) = A/E(p/sq. cm) where E is in MeV. The equivalent fluence ratio is a function of the cover glass shield thickness or the corresponding cutoff energy E(sub c). In terms of the cutoff energy, the equivalent 1 MeV electron fluence ratio is r(sub p)(E sub c) = 10(9)/E(sub c)(1.8) where E(sub c) is in units of KeV.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 112-117
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  • 36
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    Cell and defect behavior in lithium-counterdoped solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Some n(+)/p cells in which lithium is introduced as a counterdopant, by ion-implantation, into the cell's boron-doped p-region were studied. To determine if the cells radiation resistance could be significantly improved by lithium counterdoping. Defect behavior was related to cell performance using deep level transient spectroscopy. Results indicate a significantly increased radiation resistance for the lithium counterdoped cells when compared to the boron doped 1 ohm-cm control cell. The increased radiation resistance of the lithium counterdoped cells is due to the complexing of lithium with divacancies and boron. It is speculated that complexing with oxygen and single vacancies also contributes to the increased radiation resistance. Counterdoping silicon with lithium results in a different set of defects.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 102-110
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  • 37
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    On-orbit performance of LIPS gallium arsenide solar cell experiment (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Telemetry from the Living Plume Shield's gallium arsenide solar panel experiment was evaluated to determine degradation. The data were culled to preclude spurious results from possible shadowing or inaccurate measurements on a cold array. Two independent methods were then used to obtain the maximum power points and the various characteristics of the solar array. Fill factor, open circuit voltage, short circuit current, and series and shunt resistances were examined. The data analysis concluded that, to date, nearly all of the solar array degradation is due to the reduction in the short circuit current.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 81-89
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  • 38
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    Radiation tolerance of low resistivity, high voltage silicon solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The radiation tolerance of the following three low resistivity, high voltage silicon solar cells was investigated: (1) the COMSAT MSD (multi-step diffused) cell, (2) the MinMIS cell, and (3) the MIND cell. A description of these solar cells is given along with drawings of their configurations. The diffusion length damage coefficients for the cells were calculated and presented. Solar cell spectral response was also discussed. Cells of the MinMIS type were judged to be unsuitable for use in the space radiation environment.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Space Photovoltaic Res. and Technol. 1983; p 74-80
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  • 39
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    Piecewise simulaton proton test of gallium arsenide and thin silicon solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Gallium Arsenide (GaAs) solar cells are viewed as a potential primary power source on certain future Earth orbiting satellites. However, the relative merits of gallium arsenide over silicon in a space radiation environment are largely unknown because a general degradation model for gallium arsenide does not exist. The results of a test simulating the proton radiation environment existing in a polar orbit and the concomitant effects on GaAs and thin silicon (Si) solar cells are presented. The objectives and methodology of the simulation test were discussed. The electrical characteristics of GaAs and Si solar cells are given in graph form. It was concluded that GaAs cells are viable for use on satellites in low Earth orbit.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 63-73
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  • 40
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    Solar cell degradation in proton radiation orbits (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Significant discrepancies have been observed between predicted and actual in-orbit silicon solar array degradation in orbits other than LEO (low Earth orbits) and GEO (geosynchronous orbit). These discrepancies have been diagnosed to arise probably from a combination of a lack of appropriate solar cell test data and from inadequacies in the models that relate the unidirectional and mono-energetic proton test data to the omnidirectional flux-energy spectra actually found in orbit. Relative damage coefficients and solar cell power outputs were discussed, and also were presented in graph form. Silicon and gallium arsenide solar cells were considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 49-55
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  • 41
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    Radiation testing of GaAs on CRRES and LIPS experiment (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The radiation damage of solar cells has become a prime concern to the U.S. Air Force due to longer satellite lifetime requirements. Flight experiments were undertaken on the Navy Living Plume Shield (LPS) satellite and the NASA/Air Force Combined Release and Radiation Effects Satellite (CRRES) to complement existing radiation testing. Each experiment, the rationale behind it, and its approach and status are presented. The effect of space radiation on gallium arsenide (GaAs) solar cells was the central parameter investigated. Specifications of the GaAs solar cells are given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 41-48
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  • 42
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    Two-dimensional computer simulation of EMVJ and grating solar cells under AMO illumination (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A computer program, SCAP2D (Solar Cell Analysis Program in 2-Dimensions), is used to evaluate the Etched Multiple Vertical Junction (EMVJ) and grating solar cells. The aim is to demonstrate how SCAP2D can be used to evaluate cell designs. The cell designs studied are by no means optimal designs. The SCAP2D program solves the three coupled, nonlinear partial differential equations, Poisson's Equation and the hole and electron continuity equations, simultaneously in two-dimensions using finite differences to discretize the equations and Newton's Method to linearize them. The variables solved for are the electrostatic potential and the hole and electron concentrations. Each linear system of equations is solved directly by Gaussian Elimination. Convergence of the Newton Iteration is assumed when the largest correction to the electrostatic potential or hole or electron quasi-potential is less than some predetermined error. A typical problem involves 2000 nodes with a Jacobi matrix of order 6000 and a bandwidth of 243.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 34-40
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  • 43
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    Recent advances in LPE GaAs-based solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Several modifications were made to an infinite solution liquid phase epitaxy system that help fabricate both GaAs-based cells and thin cells that effectively reduce power-to-weight ratio for space applications. The most important development is the multiwell crucible for multilayer growth. Using a split crucible in one system, as many as five layers were grown in succession with varying Al levels and dopants. The structures grown were used to produce thin GaAs cells only 10 to 20 microns thick and also to grow cascade cell components. Results of these studies are presented and their applications to the future development of GaAs-based cells are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 12-17
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  • 44
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    Structurally stable, thin silicon solar cells (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A fabrication process for structurally stable thin solar cell wafers that produce good power output after irradiation is described. The fabrication process is as follows. A 6 mil, circular wafer is oxidized on both sides. One side is then patterned with a rectangular array of holes in the oxide that are nominally 75 mils square and separated by 2 mil spacings. Wells are then etched into the silicon with KOH to a depth of 4 mils, leaving a 2 mil, unetched thickness. Two areas on the surface are left unetched to provide pads for bonding or testing. All oxide is then removed and the rest of the processing is normal; the unetched face is used as the illuminated face. When all other processing is complete, a 2 X 2 cm cell is sawed from the starting wafer leaving a border that is approximately 10 mils wide. The effective thickness, determined by weighing an unmetallized sample, of such a cell is about 2.4 mil.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Research Center Space Photovoltaic Res. and Technol. 1983; p 8-11
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  • 45
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    Advanced photovoltaic experiment (S0014) (1984)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The advanced photovoltaics-related experiments for investigating a portion of the solar spectrum and the effect of the space environment on photovoltaics. The information will be used to provide correlation between space and ground testing and also to provide for more accurate performance measurement in the laboratory. Specific objectives of these experiments are to provide information on the performance and endurance of advanced and conventional solar cells, to improve reference standards for photovoltaic measurements, and to measure the energy distribution in the extraterrestrial solar spectrum. Data to be obtained will include temperatures and short-circuit current of the samples. Six-point current-voltage (I-V) characteristics will be obtained for selected samples. These data will be recorded once a day during the flight. Orbit data will be correlated with preflight and postflight measurement of the samples.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Langley Research Center Long Duration Exposure Facility (LDEF); p 88-90
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  • 46
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    Determination of optimum sunlight concentration level in space for 3-5 cascade solar cells (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Current-voltage curves were calculated for each cell in a cascade structure using a solar cell diode equation and superposition. Terms for the light generated current, diffusion current, space charge recombination current and series and shunt resistance are included. Individual current voltage curves are added in series with ohmic resistance losses for the cell interconnects to obtain the cascade cell performance. Temperature was varied with concentration, using several models, and ranged from 55 C at one Sun to between 80 and 200 C at 100 Suns. A variety of series resistance and internal resistances were used. Coefficients of the diffusion and recombination terms are strongly temperature dependent. The study indicates that maximum efficiency (30%) occurs in the 50 to 100X Sun concentration range, provided series resistance is below 0.015 ohm-sq cm and cell temperature is 80 C at 100 Suns.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 265-270
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  • 47
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    Effects of processing and dopant on radiation damage removal in silicon solar cells (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Gallium and boron doped silicon solar cells, processed by ion implantation followed by either laser or furnace anneal were irradiated by 1 MeV electrons and their postirradiation recovery by thermal annealing was determined. During the postirradiation anneal, gallium doped cells prepared by both processes recovered more rapidly and exhibited none of the severe reverse annealing observed for similarly processed 2 ohm-cm boron doped cells. Ion implanted furnace annealed 0.1 ohm-cm boron doped cells exhibited the lowest post-irradiation annealing temperatures after irradiation. The drastically lowered recovery temperature is attributed to the reduced oxygen and carbon content of the 0.1 ohm-cm cells. Analysis based on defect properties and annealing kinetics indicates that further reduction in annealing temperature is attainable with further reduction in the silicon's carbon and/or divacancy content after irradiation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ESA Photovoltaic Generators in Space; p 89-93
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  • 48
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    Science operations with Space Telescope (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The operation, instrumentation, and expected contributions of the Space Telescope are discussed. Space Telescope capabilities are described. The organization and nature of the Space Telescope Science Institute are outlined, including the allocation of observing time and the data rights and data access policies of the institute.
    Keywords: ASTRONOMY
    Type: The Space Telescope Obs.; p 1-15
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  • 49
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    Power Sources Symposium, 31st, Atlantic City, NJ, June 11-14, 1984, Proceedings (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The present conference on electrochemical power sources encompasses systems of such types as the thermoelectric, advanced rechargeable, lithium reserve, rechargeable, and nonrechargeable, nickel-cadmium and nickel-hydrogen rechargeable, lead-acid, nickel-zinc and nickel-iron rechargeable, nickel-cadmium and nickel-hydrogen rechargeable, and fuel cells. Attention is given to Si-Ge alloy multicouple technology, sodium-sulfur battery development status, the safety aspects of a rechargeable lithium C cell, fiber-structure electrodes for nickel-cadmium batteries, energy density improvements in Li/carbon monofluoride cells, zinc-air button cell technology, catalyzed cathodes for Li/SOCl2 cells, the effect of polymer structure on the rate capability of the lithium-iodine cell, and a methanol fuel cell powerplant.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 50
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    Infrared mapping of galaxian centers: Star forming regions with kiloparsec scale sizes (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A 1 to 20 micron mapping of the centers of galaxies encompassing the regions that extend out to several kiloparsecs from the nuclei is reviewed. Power emerging at or = 5 microns is a direct measure of the number of young stars present. This conclusion is strongly supported by the large-scale association of the infrared-emitting regions with visual continuum and line emission indicative of young stars, and by the similarity of the energy distributions to those of Galactic HII region/molecular cloud complexes. Much of the young-star activity is completely hidden from view. At shorter wavelengths, a variety of processes, including bremsstrahlung, are evident.
    Keywords: ASTRONOMY
    Type: Royal Observatory Star Formation Workshop; p 183-198
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  • 51
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    The Gamma-Ray Observatory mission objectives and its significance for gamma-ray astronomy (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The Gamma Ray Observatory (GRO) is an approved NASA mission, programmed for launch in 1988. Its complement of four detectors has established goals: (1) to study the nature of compact gamma-ray sources such as neutron stars and black holes, or objects whose nature is yet to be understood; (2) to search for evidence of nucleosynthesis especially in the regions of supernovae; (3) to study structural features and dynamical properties of the Galaxy; (4) to explore other galaxies, especially the extraordinary types such as radio, Seyferts, and quasars; and (5) to study cosmological effects by examining the diffuse radiation in detail. This paper discusses the design, objectives, and expected scientific results of each of the GRO instruments in view of the GRO mission goals.
    Keywords: ASTRONOMY
    Type: Advances in Space Research (ISSN 0273-1177); 3; 10-12
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  • 52
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    Hydrogen from renewable energy - Photovoltaic/water electrolysis as an exemplary approach (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A feasibility study has been conducted for a NASA Kennedy Space Center liquid hydrogen/liquid oxygen production facility using solar cell arrays as the power source for electrolysis. The 100 MW output of the facility would be split into 67.6 and 32 MW portions for electrolysis and liquefaction, respectively. The solar cell array would cover 1.65 sq miles, and would be made up of 249 modular 400-kW arrays. Hydrogen and oxygen are generated at either dispersed or centralized water electrolyzers. The yearly hydrogen output is projected to be 5.76 million lbs, with 8 times that much oxygen; these fuel volumes can support approximately 18 Space Shuttle launches/year.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 53
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    Reflectance of metallic indium for solar energy applications (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: An investigation has been conducted in order to compile quantitative data on the reflective properties of metallic indium. The fabricated samples were of sufficiently high quality that differences from similar second-surface silvered mirrors were not apparent to the human eye. Three second-surface mirror samples were prepared by means of vacuum deposition techniques, yielding indium thicknesses of approximately 1000 A. Both hemispherical and specular measurements were made. It is concluded that metallic indium possesses a sufficiently high specular reflectance to be potentially useful in many solar energy applications.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 32; 2, 19; 311
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  • 54
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    Increased radiation resistance in lithium-counterdoped silicon solar cells (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Lithium-counterdoped n(+)p silicon solar cells are found to exhibit significantly increased radiation resistance to 1-MeV electron irradiation when compared to boron-doped n(+)p silicon solar cells. In addition to improved radiation resistance, considerable damage recovery by annealing is observed in the counterdoped cells at T less than or equal to 100 C. Deep level transient spectroscopy measurements are used to identify the defect whose removal results in the low-temperature aneal. It is suggested that the increased radiation resistance of the counterdoped cells is primarily due to interaction of the lithium with interstitial oxygen.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Applied Physics Letters (ISSN 0003-6951); 44; 1071-107
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  • 55
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    Sheet silicon cell/module technology (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The cost involved in the performance of the standard operations for the manufacture of silicon wafers is insignificant in the case of space photovoltaics applications. It is, however, a decisive factor with respect to terrestrial applications of silicon photovoltaic devices. In 1975, a program was, therefore, begun to develop low cost silicon solar arrays for terrestrial applications. The goal was silicon-based photovoltaic (PV) modules ready for installation at a selling price of $0.50/watt (1975 dollars). Sheet and ribbon silicon growth held out the promise of reduced cost through continuous operation, high material throughput, high material utilization efficiency, and a product whose shape lent itself to the assembly of high packing density modules. Attention is given to ribbon growth technologies, sheet technology generic problems, and ribbon cell and module technology status. It is concluded that the potential for crystalline ribbon silicon appears to be better today than ever before.
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  • 56
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    The S201 far-ultraviolet imaging survey. II - A field in Cygnus (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Far-ultraviolet imagery of a region in Cygnus, a 20 deg diameter field centered near (1950) R. A. 21 h 31.2 m decl. +37 deg 25 arcmin, was obtained by the S201 far-ultraviolet camera during the Apollo 16 mission. In a 10 minute exposure covering the 1250-1600 A wavelength range (effective wavelength 1400 A), 730 star images can be detected, corresponding to a limiting ultraviolet magnitude of about m (1400) = 10. Assuming nominal interstellar extinction values in this region near the galactic plane, this result corresponds to the detection of A0 V stars to a distance of 300 pc and of B0 V stars to 1500 pc. Uncertainties in spectral classification and interstellar extinction for individual objects are probably more significant than calibration or measurement errors. Most of the objects detected are identified with stars in the Smithsonian Astrophysical Observatory Star Catalog (1966), or the Catalog of Stellar Identifications (1979) or both, but 87 objects remain unidentified (or are identified with late-type stars).
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 54; 271-290
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  • 57
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    Determining asteroid masses from perturbations on Mars (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The orbit of Mars is perturbed more than 5 m, a value compatible with the accuracy of the Viking Lander ranging data, by about three dozen asteroids. In addition to larger asteroids throughout the belt, significant perturbations of long period are generated by smaller objects near commensurabilities with Mars. The largest periodic terms induced by 1 Ceres and 2 Pallas have amplitudes of 0.8 and 0.2 km, respectively, both with 10-year periods. Due to a near commensurability, 4 Vesta causes a 5-km, 52-year term. While the Viking ranges will yield significant mass determinations for the largest three asteroids, and some of the smaller bodies should be detectable, it will be difficult to separate the smaller bodies with useful accuracies. Accurate discrimination must await range data from future missions to Mars or other bodies in the neighborhood of the asteroid belt. The Viking ranges can also yield improved masses for the outer planets (except Pluto), an application which is being exploited by groups analyzing these data. Uncertainties in the asteroid masses limit the ultimate accuracy of the Viking determinations of both the long time scale motion of the system of the inner four planets with respect to an inertial frame and the rate of change of the gravitational constant.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 57; 1-13
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  • 58
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    Investigation of energy management strategies for photovoltaic systems - A predictive control algorithm (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The present investigation is concerned with the formulation of energy management strategies for stand-alone photovoltaic (PV) systems, taking into account a basic control algorithm for a possible predictive, (and adaptive) controller. The control system controls the flow of energy in the system according to the amount of energy available, and predicts the appropriate control set-points based on the energy (insolation) available by using an appropriate system model. Aspects of adaptation to the conditions of the system are also considered. Attention is given to a statistical analysis technique, the analysis inputs, the analysis procedure, and details regarding the basic control algorithm.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 59
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    A search for the 10-micron silicate feature in periodic Comet Grigg-Skjellerup (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A 10-micron spectrum of periodic Comet Grigg-Skjellerup was obtained on 22 June 1982 with the UCL array spectrometer at the United Kingdom Infrared Telescope, Mauna Kea. No emission feature is obvious in the spectrum. The observed spectrum can be fit equally well by a model of small hot absorbing grains or by a composite model with less than or equal to 30 percent (3sigma) warm, 'dirty' silicate grains. The latter model is consistent with the silicate abundance in Comet Kohoutek, which did display an emission feature at 10 microns.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 89; 170
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  • 60
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    Broad band X-ray astronomical spectroscopy (1984)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The Broad Band X-Ray Telescope (BBXRT) experiment has been designed for high sensitivity, moderate resolution spectrophotometry of cosmic sources in the range 0.5 to 12 keV. Principal elements are two co-aligned imaging telescopes with cooled Si(Li) detectors at each focus. The mirror design uses an approximate geometry of tightly nested, conical, foil reflectors that allow a large filling factor (high throughput) at small grazing angles (high energy response). Each detector consists of a cluster of five elements defined with grooves on a single crystal. This arrangement affords some spatial resolution as well as a means of substantial background reduction. Shuttle borne measurements will typically be of 2000 s duration for sources with a flux of 10 to the -12 erg/sq cm-s.
    Keywords: ASTRONOMY
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-31; 786-790
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    Design, installation and operating experience of 20 photovoltaic medical refrigerator systems on four continents (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NASA Lewis Research Center in cooperation with the World Health Organization, U.S.A. I.D., the Pan American Health Organization and national government agencies in some developing countries sponsored the installation of twenty photovoltaic powered medical vaccine storage refrigerator-freezer (R/F) systems. The Solar Power Corporation was selected as the contractor to perform the design, development and installation of these twenty units. Solar Power's experiences are described herein.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 62
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    Development of a photovoltaic module qualification test based on combined-environment accelerated stress data (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The U.S. Coast Guard has developed a qualification test to screen photovoltaic modules for utilization on marine aids to navigation. The test is based on a combined-environment of hot and cold saltwater immersion and air pressurization. The test has demonstrated a very high acceleration factor and excellent correlation of electrical failures with modules in a concurrent real-time marine exposure.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 63
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    Design principles for high efficiency small-grain polysilicon solar cells, with supporting experimental studies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Design principles suggested here aim toward high conversion efficiency (greater than 15 percent) in polysilicon cells. The principles seek to decrease the liabilities of both intragranular and grain-boundary-surface defects. The advantages of a phosphorus atom concentration gradient in a thin (less than 50 microns) base of a p(+)/n(x)/n(+) drift-field solar cell, which produces favorable gradients in chemical potential, minority-carrier mobility and diffusivity, and recombination lifetime (via phosphorus gettering) are suggested. The degrading effects of grain boundaries are reduced by these three gradients and by substituting atoms (P, H, F or Li) for vacancies on the grain-boundary surface. From recent experiments comes support for the benefits of P diffusion down grain boundaries and, for quasi-grain-boundary-free and related structures. New analytic solutions for the n(x)-base include the effect of a power-law dependence between P concentration and lifetime. These provide an upper-bound estimate on the open circuit voltage. Finite-difference numerical solutions of the six Shockley equations furnish complete information about all solar-cell parameters and add insight concerning design.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 64
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    Residential photovoltaic power conditioning technology for grid connected applications (1982)
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    Publication Date: 2011-08-18
    Description: Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 65
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    Design solutions for the solar cell interconnect fatigue fracture problem (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Mechanical fatigue of solar cell interconnects is a major failure mechanism in photovoltaic arrays. A comprehensive approach to the reliability design of interconnects, together with extensive design data for the fatigue properties of copper interconnects, has been published. This paper extends the previous work, developing failure prediction (fatigue) data for additional interconnect material choices, including aluminum and a variety of copper-Invar and copper-steel claddings. An improved global fatigue function is used to model the probability-of-failure statistics of each material as a function of level and number of cycles of applied strain. Life-cycle economic analyses are used to evaluate the relative merits of each material choce. The copper-Invar clad composites demonstrate superior performance over pure copper. Aluminum results are disappointing.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 66
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    Optimal design of high-efficiency tandem cells (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Computer analysis indicates that a substantial increase in solar cell conversion efficiencies can be achieved by using two-cell, multi-bandgap tandem structures instead of single-junction cells. Practical AM1 efficiencies of about 30 percent at one sun and over 30 percent at multiple suns are to be expected. The further increases in efficiency calculated for a three-cell tandem structure are much smaller and may not justify the added complexity. For inexpensive two-cell tandem modules, Si is preferred for the bottom cell, and the top-cell material should have a bandgap of 1.75 to 1.80 eV. The GaAs-AlAs and GaAs-GaP systems are very attractive candidates for the top cell. Significant advances have been achieved in growing GaAs on Ge-coated Si substrates (for the two-terminal, two-cell structure) and in growing free-standing ultrathin GaAs layers (for the two-terminal or four-terminal structures). These advances should be transferable to the GaAs-AlAs and GaAs-GaP systems.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 67
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    Characterization of the electrical output of flat-plate photovoltaic arrays (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The electric output of flat-plate photovoltaic arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as direct-current to alternating-current power conditioners must be able to accommodate widely varying input levels, while maintaining operation at or near the array maximum power point.The results of an extensive computer simulation study that was used to define the parameters necessary for the systematic design of array/power-conditioner interfaces are presented as normalized ratios of power-conditioner parameters to array parameters, to make the results universally applicable to a wide variety of system sizes, sites, and operating modes. The advantages of maximum power tracking and a technique for computing average annual power-conditioner efficiency are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 68
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    Discharge characteristics of a simulated solar cell array (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Measurements of the transient characteristics associated with the discharge of a simulated solar array are presented. A capacitively coupled probe is used to measure the discharge current, and antennas are used to measure the electromagnetic radiation. Discharges were observed at low surface voltages and several modes of discharge were observed. The maximum discharge current is found to be 0.2 A. This value is several orders of magnitude higher than that reported by previous measurements. Experimental evidence suggests that the inverted voltage gradient is a very likely triggering mechanism for solar array discharges.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4311-431
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  • 69
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    Ultraviolet spectra of planetary nebulae. X - Physical conditions in the compact planetary nebula Sw St 1 (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photoelectric visual and ultraviolet observations of the compact planetary nebula Sw St 1 are analyzed. The electron density, determined from the C III 1907/1909 A line ratio, is N(e) = (1.1 + or - 0.1) x 10 to the 5th/cu cm, consistent with the high emission measure and high critical frequency determined from observations of the thermal radio emission. The C/O abundance ratio in the nebula is found to be N(C)/N(O) = 0.72 + or - 0.1, i.e. the envelope is oxygen-rich, as suggested by the identification of the silicate feature in the 8-13 micron infrared spectrum. Difficulties remain in accurately determining the reddening constant to the nebula and its electron temperature.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 206; 293-304
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  • 70
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    Detection of silicate emission features in the 8- to 13-micron spectra of main belt asteroids (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A presentation is given of 8.0-13.0 micron spectra (Delta lambda/lambda = 0.02-0.03) for six main belt asteroids, which range from 58 to 220 km in diameter and sample the five principal taxonomic classes (C, S, M, R and E). Narrow, well-defined silicate emission features are present on two of the asteroids, the C-type 19 Fortuna and the M-type 21 Lutetia. No comparable emission features are observed on the S-types 11 Parthenope and 14 Irene, the R-type 349 Dembowska or the E-type 64 Angelina.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 56; 393-397
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  • 71
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    Glossary of terms used in solar energy (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy (ISSN 0038-092X); 33; 1, 19
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  • 72
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    Radioastronomical observations of comets IRAS-Araki-Alcock (1983d) and Sugano-Saigusa-Fujikawa (1983e) (1984)
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    Publication Date: 2011-08-19
    Description: Continuum and spectral-line radio observations of the comets IRAS-Araki-Alcock and Sugano-Saigusa-Fujikawa obtained at a number of observatories during May and June, 1983, are compiled in tables and briefly characterized. The species NH3, H2O, CO, and HCN are considered in detail; visible-range observations of CN are compared; and the implications of the results and the experience gained in performing and coordinating the observations for the detection of important species in other comets, especially Halley's Comet, are explored.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 60; 215-220
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  • 73
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    A search at the millijansky level for milli-arcsecond cores in a complete sample of radio galaxies (1984)
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    Publication Date: 2011-08-19
    Description: A complete sample of 26 extended radio galaxies was observed at 2.29 GHz with the Mark III VLBI system. The fringe spacing was about 3 milli-arcsec, and the detection limit was about 2 millijanskys. Half of the galaxies were found to possess milli-arcsec radio cores. In all but three sources, the nuclear flux density was less than 0.04 of the total flux density. Galaxies with high optical luminosity (less than -21.2) were more likely than less luminous galaxies to contain a detectable milliparcsec radio core (69 percent vs. 20 percent). For objects with arcsec cores, 80 percent were found to have a milli-arcsec core, even though the milli-arcsec object did not always contribute the greater part of the arcsec flux density.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 284; 519-522
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  • 74
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    The evolution of the infrared emission from the Type II supernova 1980k in NGC 6946 - The dust formation model (1983)
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    Publication Date: 2011-08-18
    Description: The paper presents 1-4 micron photometry of supernova 1980 k in NGC 6946 obtained over a period of 1 year following the outburst. During the period between 1980 November 1 and December 19, the infrared emission probably originated from the extended atmosphere of the expanding star. The JHKL colors and a 1.3-2.6-micron spectrum observed during this period correspond to those of a blackbody with an average temperature of about 5000 K. Observations around 1981 May 31 showed that the supernova developed an infrared excess after 1980 December. This infrared excess persisted through 1981 October and is consistent with the appearance of thermal emission from about 700 to 900 K dust in addition to a hotter photosphere. The similarity of this behavior to that of the infrared evolution of some novae suggests that dust formation may be occurring in the supernova ejecta. The hypothesis, that the emission arises from preexisting grains in a circumstellar shell which are heated by the supernova outburst, is also consistent with the data.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 274; 168-174
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  • 75
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    Ultraviolet and optical studies of binaries with luminous cool primaries and hot companions. III - Reticon radial velocities (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Radial velocities for 72 stars, most of them known or suspected binaries with F - K giant-supergiant primaries, are derived from Reticon spectra in the region 6005-6235 A at a scale of 7 km/s per diode. Cross-correlation of the spectra normally produces results accurate to better than 1.0 km/s. Eight new radial velocity variables are found (HR 2786, R Pup, HR 3291, HR 4451, HD 114520, HR 5667, HR 7014, and Nu1 Sgr). Improved orbits are determined for 15 known spectroscopic binaries, and provisional orbits are obtained for seven new spectroscopic binaries.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 53; 553-571
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    Infrared observations of RS CVn stars (1983)
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    Publication Date: 2011-08-18
    Description: The paper presents infrared photometry of the RS CVn binary stars AR Lac (1.2-10 microns) and MM Her (1.2-3.5 microns) as they egressed from their primary and secondary eclipses; of the eclipsing systems RS CVn and Z Her at maximum light (1.2-10 microns) and of the non-eclipsing systems UX Ari and HR 1099 (1.2-10 microns). An analysis of these and published V data based on flux ratio diagrams (linear analogues of color-color diagrams) shows that G and K stars supply the infrared light of these systems. In AR Lac, the combined light of a G5-K0 subgiant and either a late F dwarf or an early F subgiant can account for the observed visual and infrared light curves. None of these systems shows infrared emission from circumstellar matter. This result is simply understood: dust grains would not be expected to form in the physical conditions surrounding the subgiant, and the corona and chromosphere (whose properties have been deduced from spectroscopic X-ray observations) should not produce appreciable infrared emission.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 205; 859-873
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  • 77
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    Ultraviolet high-resolution spectroscopy from the Space Telescope (1983)
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    Publication Date: 2011-08-18
    Description: The High Resolution Spectrograph is one of five scientific instruments which will be part of the Space Telescope observatory. The spectrograph was designed to take advantage of the imaging and pointing capabilities of the telescope to obtain ultraviolet spectra with spectral resolution comparable to large, ground-based coudeinstruments. Some of the results of the ground-based testing program will be described, along with applications of these properties to future science programs.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 95; 543-549
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  • 78
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    Theoretical studies of the effects of grain noise on photographic stellar astrometry and photometry (1983)
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    Publication Date: 2011-08-18
    Description: A method of incorporating the effects of photographic emulsion grain noise into digital image centering algorithms is presented which improves the accuracy of the derived stellar positions and magnitudes. Theoretical formulae are then derived for the limiting error of the center, and the photometric parameters. For IIIa-J, this error is 0.2-0.3 mu for bright unsaturated images, which agrees quite well with measurements made with the Yale PDS microdensitometer. It is expected that, with further improvements in the positional accuracy of the PDS, it should be possible to reach the emulsion grain noise limit, providing that emulsion shifts or other large scale errors do not dominate. It is also shown that, with appropriate trimming, marginal distribution image centering algorithms can yield an accuracy only slightly poorer than that obtained with two-dimensional distributions.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 88; 1683-168
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  • 79
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    An improved celestial radio reference frame: JPL 1982-4 (1983)
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    Publication Date: 2011-08-18
    Description: In the development of a celestial radio reference frame, there are now over 100 sources whose relative positions are known with an average uncertainty less than 5 milliarcseconds. These sources are fairly uniformly distributed over the celestial sphere north of -40 deg declination. Their positions are expressed in the new IAU system. This presentation describes the analysis involved in obtaining these results, as well as future plans for linking this system to the JPL planetary ephemerides.
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  • 80
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    New infrared observations of IRS1, IRS3, and the adjacent nebula in the OMC-2 cluster (1984)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. Results show that the asymmetric distribution of the extended emission seen about IRS1 is another infrared reflection nebula. Energy distributions show that the spectral shape is fairly constant throughout the nebula which indicates there is little internal extinction within this region. Integrated surface brightness values show that the nebula is 5 times brighter than IRS1 at K. Energy distributions show that IRS1 has a more pronounced ice band absorption feature at 3.1 micron; suggesting that there is more extinction along the direct line of sight to IRS1 than along a line from IRS1 to the scattering grains and then to the observer. The distribution of the extended emission around IRS1 is similar to the reflection nebula seen in NGC 7538 (Werner et al. 1979). The asymmetric shapes of the two nebulae are similar and in each case there is excess extinction along line of sight to the illuminating source.
    Keywords: ASTRONOMY
    Type: Royal Observatory Lab. and Observational Infrared Spectra of Interstellar Dust; p 162-166
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  • 81
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    Transient dips of Cygnus X-1 observed from Tenma (1984)
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    Publication Date: 2011-08-19
    Description: The transient intensity dips of the binary system Cyg X-1 have been observed, using the gas scintillation proportional counter (GSPC) array onboard the Tenma X-ray astronomy satellite. The duration of the dips was in the range from several seconds to 10 minutes, with several dips occurring as much as 15 h before the superior conjunction. Within the dips, complex structures were observed with time scales of several seconds, and, in at least one case, shorter than two seconds. For a dip lasting longer than 10 minutes, a high-quality spectrum was obtained which reveals the K-absorption edge of iron at 7.18 + or - 0.18 keV. On the basis of the observed absorption, it is suggested that the dips are caused by absorption due to relatively cool matter (less than about 30,000 k); the low-energy excess observed during the dips is due either to an extended soft X-ray emitting corona or to partial obscuration of the X-ray source by multiple blobs. From the time structure of the dip, a blob size of the order of 10 to the 9th cm is derived.
    Keywords: ASTRONOMY
    Type: Astronomical Society of Japan, Publications (ISSN 0004-6264); 36; 4, 19
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  • 82
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    High-temperature thermoelectric energy converstion. I - Theory (1984)
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    Publication Date: 2011-08-19
    Description: The high-temperature thermoelectric energy-conversion theory is examined. It is shown that semiconductors are the logical choices for high-figure of merit-value materials, but the requirements for optimization differ depending on whether the material is classed as a broad-band or narrow-band semiconductor. Optimization is discussed as a function of temperature. Phonon scattering mechanisms are considered; and for the reduction of thermal conductivity, basic material guidelines are given. Although experimental results indicate that ZT (where Z is the figure of merit and T is the temperature) of about 1 represents an upper limit, there is in fact, no theoretical limitation. It is unlikely that the Z values will be significantly reduced by radiation transfer at temperatures lower than 2000 K. The current status of materials research is also considered. The rare-earth chalcogenides which behave as n-type semi-conductors and the boron-rich borides which exhibit hopping p-type conductivity behavior are the materials that show promise for high-temperature Z values. The reasons for low thermal conductivities in these materials is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Energy Conversion and Management (ISSN 0196-8904); 24; 4, 19; 317-329
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  • 83
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    Solar tests of aperture plate materials for solar thermal dish collectors (1984)
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    Publication Date: 2011-08-19
    Description: If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluoroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fall apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 84
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    IUE observations of the 'Butterfly' Nebula M2-9 (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: IUE observations of the peculiar 'Butterfy' nebula M2-9 indicate that it is not a normal planetary nebula. The ultraviolet spectrum is characterized by few emission lines and a weak continuum. Mg II 2800 A is the strongest emission line present and may be indicative of a binary nucleus. Lines of N v, Q I, N III, N IV, Si III, and C III are seen, but C IV and O III are conspicuous by their absence. T(e) = 10,250 + or - 400 K was determined for the core. Nitrogen in the core is found to be overabundant by about a factor of 5 over the solar value. M2-9 may be an object in the early stages of becoming a planetary nebula.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 287; 353-358
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  • 85
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    Cometary showers and unseen solar companions (1984)
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    Publication Date: 2011-08-19
    Description: The possibility that an invisible solar companion passing through the Oort cloud every 28 Myr precipitates a sufficiently high rate of cometary collisions with the earth to account for periodic mass species extinctions recorded in the fossil record is discussed. A Monte Carlo simulation shows that any hypothesized 'death star' with a 28 Myr orbit would experience an average 10 percent change in period per orbit. Production of an 18-fold increase in cometary impacts would be associated with a 0.055 probability that a 10 km nucleus would hit the earth in a shower once every 510 Myr, longer than the proposed extinction periodicity. However, if the death star orbit has a 0.6 eccentricity and the Oort cloud is sufficiently densely populated, a 2 billion comet shower may be possible. A survey of large terrestrial impact craters indicates that 6-12 craters with diameters over 10 km originated in periodic showers. The extinctions in any case occur at 26 Myr periods and cannot be correlated with the 33 Myr period of recrossing the galactic plane, or with any other known phenomena.
    Keywords: ASTRONOMY
    Type: Nature (ISSN 0028-0836); 312; 380; Rep
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  • 86
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    Near-optimum design of GaAs-based concentrator space solar cells for 80 C operation (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Using a detailed computer simulation model and reasonable values of optical, geometrical and material parameters from current published literature, parameter optimization studies were performed on two cell geometries, namely, the circular geometry for a Cassegrainian concentrator with 100 AM0, 80 C operation and the rectangular geometry for a venetian blind concentrator with 20 AM0, 80 C operation. For each cell geometry, three cell configurations were considered: p/n AlGaAs/GaAs; n/p AlGaAs/GaAs; and, n/p GaAs shallow homojunction. The studies show the possibility of designing GaAs-based space solar cells with beginning-of-life efficiencies exceeding 22 percent at 20 to 100 AM0, 80 C and probable efficiency degradation of less than 15 percent after a 70 percent reduction in diffusion length in each cell region.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Applied Physics Communications (ISSN 0277-9374); 4; 2-3,; 97-119
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  • 87
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    Evidence for material between Saturn's A and F rings from the Voyager 2 photopolarimeter experiment (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The region in the Saturn system between the F ring and the outer edge of the A ring is an area that appears, in images from the imaging experiment, to be virtually devoid of material except for three small satellites. Near the orbit of 1980S28, Atlas - the innermost satellite - the Voyager Photopolarimeter Stellar Occultation data show a discontinuity in count rate which marks a boundary between the tenuous material near the outer edge of the A ring and the orbit of Atlas. The data pertaining to this region have been examined with the aid of statistics and models generated from other similar ring structures. It is concluded that the discontinuity is real, implying the existence of tenuous material of normal optical depth of 0.01 to 0.006 in this region.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 60; 409-415
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  • 88
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    1984 AB - A unique Mars-crossing asteroid (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Asteroid 1984 AB, discovered in January 1984, proved to be a unique object with a close dynamical relationship to Mars. A brief history of the discovery and subsequent 'evolution' of the orbit as it was refined is presented. The preliminary orbit of 1984 AB indicated that it might be a Mars Trojan, and an extended discussion of this interesting possibility is presented, but this hypothesis had to be dismissed after further observations had refined the orbit. The semimajor axis and orbital eccentricity are very similar to that of Mars. No other known Mars-crossing asteroid exists with an orbit as closely associated to Mars.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 60; 404-408
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  • 89
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    Solar tests of aperture plate materials for solar thermal dish collectors (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: If a malfunction occurs in a solar thermal point-focus distributed receiver power plant while a concentrator is pointed at the sun, motion of the concentrator may stop. As the sun moves relative to the earth, the spot of concentrated sunlight then slowly walks off the receiver aperture, across the receiver face plate, and perhaps across adjacent portions of the concentrator. Intense local heating by the concentrated sunlight may damage or destroy these parts. The behavior of various materials under conditions simulating walk-off of a parabolic dish solar collector were evaluated. Each test consisted of exposure to concentrated sunlight at a peak flux density of about 7000 kW/square meter for 15 minutes. Types of materials tested included graphite, silicon carbide, silica, various silicates, alumina, zirconia, aluminum, copper, steel, and polytetrafluroethylene. The only material that neither cracked nor melted was grade G-90 graphite. Grade CS graphite, a lower cost commercial grade, cracked half-way across, but did not fail apart. Both of these grades are medium-grain extruded graphites. A graphite cloth (graphitized polyacrylonitrile) showed fair performance when tested as a single thin ply; it might be useful as a multi-ply assembly. High purity slipcast silica showed some promise also.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ASME, Transactions, Journal of Solar Energy Engineering (ISSN 0199-6231); 106; 408-415
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  • 90
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    Solar-cell interconnect design for terrestrial photovoltaic modules (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Useful solar cell interconnect reliability design and life prediction algorithms are presented, together with experimental data indicating that the classical strain cycle (fatigue) curve for the interconnect material does not account for the statistical scatter that is required in reliability predictions. This shortcoming is presently addressed by fitting a functional form to experimental cumulative interconnect failure rate data, which thereby yields statistical fatigue curves enabling not only the prediction of cumulative interconnect failures during the design life of an array field, but also the quantitative interpretation of data from accelerated thermal cycling tests. Optimal interconnect cost reliability design algorithms are also derived which may allow the minimization of energy cost over the design life of the array field.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: ASME, Transactions, Journal of Solar Energy Engineering (ISSN 0199-6231); 106; 379-386
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  • 91
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    A radar study of Comet IRAS-Araki-Alcock 1983d (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Radar echoes from Comet IRAS-Araki-Alcock at wavelengths 3.54 and 12.9 cm indicate that the comet's nucleus is very rough on a scale larger than the radar wavelengths; however, the low polarization ratio (25 percent at 3.54 cm) indicates that the scattering is not dominated by multiple reflections, internal reflections, or large abundances of sharp edges, cracks, and pits. The shape of the nucleus probably departs greatly from a sphere with average radii near 3-4 km. The nucleus does not appear to look significantly different from a number of Apollo and Amor asteroids except that: (1) there is a suggestion that minor structure moves rapidly across the spectra, and (2) the debris not gravitationally bound to the comet was detected, and contributes 25 percent of the total radar cross section at the 12.9-cm wavelength. Other considerations suggest that the pole was at least 45 deg away from the line of sight on two days of observation, and that the rotation period is approximately 1-2 days.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 89; 1745-175
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  • 92
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    A solar spectral line list between 10 and 200 A modified for application to high spectral resolution X-ray astronomy (1984)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A spectral line list for the 10-200 A range is developed from existing solar spectra for application to high spectral resolution measurements of astrophysical plasmas. The solar spectral line lists are merged into a single comprehensive list. The effect of the solar emission measure distribution is removed from the line intensities, which results in a set of emission rates for the lines that can be applied to many optically thin, low density high temperature plasmas in ionization equilibrium. In addition to the measured solar lines, 250 theoretical lines are added to this list. These lines fall in wavelength regions where the existing solar lists have few lines because of limitations in instrumental sensitivity. Also, some lines have been added because the sun has very little plasma at temperatures of about one million K, and consequently these lines are weak or absent in solar spectra. The entire list contains about 600 lines. Finally, predicted spectra of the two RS CVn stars, alpha Aur (Capella) and UX Ari, are presented at 1 and 0.25 A spectral resolution. Also, the solar spectrum is shown at 1 A resolution, and the emission rate spectrum (spectrum not modified by an emission measure distribution) is shown at very high spectral resolution. The predicted spectra for Capella and UX Ari are based on results obtained from the Einstein and International Ultraviolet Explorer (IUE) spacecraft.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 56; 67-89
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  • 93
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    Comets (1981)
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    Publication Date: 2011-08-18
    Description: The nature and origin of comets is discussed. Observations of the principal parts of comets, the dust and plasma tails, the hydrogen cloud, the coma and the cometary nucleus, are presented, and the icy conglomerate model of Whipple as extended by Delsemme accounting for the observed properties and their variation with heliocentric distance is examined. The origin of comets is considered in relation to the orbital statistics of the long-period comets and the existence of the Oort cloud on the edge of the solar system, and possible roles for comets in the solar nebula and the evolution of the solar system are indicated. Particular attention is then given to the discovery and properties of Halley's Comet, which is expected to reach perihelion in 1986, and to possible flyby and rendezvous missions to Halley's Comet and others.
    Keywords: ASTRONOMY
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  • 94
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    Electron densities for 10 planetary nebulae derived from the semiforbidden C III lambda 1907/1909 ratio. II (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Electron densities for IC 351, IC 2165, J900, IC 3568, NGC 6644, NGC 6891, IC 4997, NGC 7009, Hu 1-2, and IC 5217 are derived from high-dispersion semiforbidden C III spectrograms. For seven of these nebulae, the derived electron density is larger than the values derived from either surface brightness measurements or forbidden line ratios. Only one object, Hu 1-2, shows pronounced splitting of the semiforbidden C III emission lines due to a large expansion velocity.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 95
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    Medium energy gamma ray astronomy with transpacific balloon flights (1981)
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    Publication Date: 2011-08-18
    Description: Transpacific balloon flights with the University of California, Riverside (UCR) double scatter telescope are discussed. With flight durations from 5 days up to perhaps 15 days the long observation times necessary for medium energy (1-30 MeV) gamma ray astronomy can be obtained. These flights would be made under the auspices of the Joint U.S.-Japan Balloon Flight Program at NASA. It is proposed that flights can provide at least 30 hours of observation time per flight for many discrete source candidates and 120 hours for detecting low intensity cosmic gamma ray bursts.
    Keywords: ASTRONOMY
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  • 96
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    Studies in astronomical time series analysis. I - Modeling random processes in the time domain (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Several random process models in the time domain are defined and discussed. Attention is given to the moving average model, the autoregressive model, and relationships between and combinations of these models. Consideration is then given to methods for investigating pulse structure, procedures of model construction, computational methods, and numerical experiments. A FORTRAN algorithm of time series analysis has been developed which is relatively stable numerically. Results of test cases are given to study the effect of adding noise and of different distributions for the pulse amplitudes. A preliminary analysis of the light curve of the quasar 3C 272 is considered as an example.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 45; Jan. 198
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  • 97
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    Three new 'nonterrestrial' molecules (1981)
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    Publication Date: 2011-08-18
    Description: Eight new interstellar lines have been detected from three molecules not previously observed spectroscopically in space or in the laboratory. One is a linear or nearly linear molecule with microwave constants B0 equals 21,337.15 plus or minus 0.06 MHz, D0 equals 21.4 plus or minus 1.5 kHz. This is the thioformyl ion HCS(plus), first identified because B0 and D0 are close to those calculated, and now confirmed by laboratory detection of one of the present lines (Gudeman et al.). The second molecule, also linear or nearly so, has microwave constants B0 equals 10,691,406 plus or minus 0.043 MHz, D0 equals 1.84 plus or minus 0.91 kHz close to those expected for the isoelectronic systems HOCO(plus) and HOCN; a choice between the two cannot be made on the basis of the available astronomical data. The existence of a third molecule is deduced from an unidentified line at 85,338 MHz that has been found in many sources, is fairly intense in several, and may be self-absorbed in Sgr B2.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 98
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    Discovery of phase-locked variable polarization in an RS Canum Venaticorum-like star, HR 5110 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Using measurements on 79 nights in 1980 January-August, it is established that the polarization in the ultraviolet (U band) varies synchronously on the known binary period of 2.6132 days, with a peak-to-peak amplitude of 0.03%. The pattern is mainly second harmonic in character, as typical of binary star examples such as Algol and Upsilon Her. Reflection by the cooler star, by a plasma concentration, or both, is suggested. The scale of the polarization seems to be consistent with Rayleigh scattering by neutral hydrogen on the cooler star, and a roughly lambda to the -4th wavelength dependence should be searched for. The QU curve suggests a sizeable inclination for the system, of about 45 deg, but this is preliminary. Separately, a possible weak periodicity might be present on a subsidiary period, conceivably related to a rotating star spot.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 99
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    The 45 micron H2O ice band in the Kleinmann-Low Nebula (1981)
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 100
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    Transport velocity transformation - A convenient method for performance analysis of multilayer solar cell structure (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is noted that in the case of low-level injection, space-charge quasi-neutrality, and spatially constant material parameters (including an electrostatic field), the individual layer can be treated analytically and the basic solar cell performance parameters can be evaluated from three equations. The first equation represents the transformation of the transport velocity across the layer from the other layer boundary. The second establishes the light-generated current output from the layer interface, under the influence of the transport velocities and minority-carrier density at both layer boundaries and of bulk recombination. The third equation describes the flow of these carriers across other layers. The power of the approach is considered to lie in its facility for analysis of the solar cell's performance layer by layer, giving a clear picture of the individual layer's influence on cell efficiency.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-28; May 1981
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