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  • LUNAR AND PLANETARY EXPLORATION  (723)
  • ENERGY PRODUCTION AND CONVERSION  (452)
  • 1995-1999
  • 1985-1989
  • 1980-1984
  • 1975-1979  (1,175)
  • 1940-1944
  • 1977  (1,175)
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  • 1995-1999
  • 1985-1989
  • 1980-1984
  • 1975-1979  (1,175)
  • 1940-1944
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  • 1
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A discussion is presented on nickel cadmium battery life tests using reconditioning and some comparative tests not using reconditioning. The discussion is aimed at the program application part of the testing. The goals of the program were to get an increased utilization out of the battery system in geosynchronous orbit. An attempt was made to push the depth of discharge operation up around 80 to 85 percent and the intent with the reconditioning program was to extend this type of utilization out towards a 10-year life and attune the voltage regulation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 259-270
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  • 2
    Publication Date: 2006-06-15
    Description: The mode of operation that is of interest in this discussion is a solar array battery load-sharing mode. The battery is loaded for a fraction of a second and then charged, so the cycle is a 100 millisecond load, followed by a 500 millisecond charge. The purpose of the experiment was to evaluate the charge efficiency and the state of charge. Charge/discharge ratio graphs are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 213-218
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  • 3
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The use of statistical analysis (regression analysis) to determine the data correlation between eight voltage parameters is discussed. The eight parameters correlated include: temperature, depth of discharge; charge rate; discharge rate; percent recharge; concentration of KOH; amount of KOH; and precharge. Graphs are presented which show: (1) starpoint/centerpoint cycles to failure vs. parameters; (2) cycles to failure vs. temperature; and (3) positive and negative plate thickness and weight vs. cycles. An empirical equation derived from cycles to failure vs. temperature graph for cells cycled at 1C charge, 2C discharge, and 14 percent recharge is also presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 155-172
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  • 4
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    In:  CASI
    Publication Date: 2006-06-14
    Description: As part of the NASA lightweight battery program, the Lewis Research Center has a number of programs that are being reviewed. A brief and general discussion of these programs is presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 133-136
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  • 5
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    In:  CASI
    Publication Date: 2006-06-18
    Description: After using all the instrumentation that is available on a nickel hydrogen battery it will be subjected to the same low earth orbit cycles experienced by the sixty amphere hour nickel cadmium batteries now being flown on some low earth orbit missions. The objective of the test is to demonstrate real differences between the two batteries. In order to simulate flight conditions, the thermal environment and criteria for charge control will vary. The depth of discharge will be increased and testing will continue until some failures or some degradation or spread between cell performances are revealed. Different charge control modes are being considered in order to demonstrate a reasonable life for the nickel hydrogen battery.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 517
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  • 6
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    In:  CASI
    Publication Date: 2006-06-18
    Description: An experiment to obtain some flight experience with a nickel-hydrogen battery in low earth orbit is described. The battery was built to be as compatible with the satellite bus as possible because the satellite bus is used for recharge power. The battery is mounted on an experimental pallet on the satellite. It has its own charge control system, a modification of an existing system that is used for nickel-cadmium, which primarily uses temperature compensated voltage as its criteria. Also, on the pallet is a load bank, a resistive load band, which allows switch to various load regimes. There is some other equipment on the satellite such as the nickel-hydrogen battery to power it. Monitors attached to the 21-cell battery are described.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 499-516
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  • 7
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Features of the first operational nickel hydrogen battery are described as well as experiences encountered during its testing and installation. Battery performance since launching of the NTS-2 satellite is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 489-498
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  • 8
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Test data developed primarily on low earth, but also some accelerated synchronous orbit data are presented for first 40 hour ampere hour boiler plate cells. Graphic data show the following characteristics: charge/discharge voltage; charge/discharge temperature; voltage; pressure; temperature; and discharge voltage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 481-487
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  • 9
    Publication Date: 2006-06-18
    Description: The effects of overcharge and total cycling rate on one electrochemically impregnated and four chemically impregnated nickel electrodes are examined. Topics discussed include porosity distribution, electrode corrosion, electrolyte absorption and positive electrode involvement in the decrease in the amount of electrolyte in the separator. The electrochemically impregnated electrode is shown to be superior to all types of conventionally impregnated electrodes regardless of the loading level.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center. The 1977 Goddard Space Flight Center Battery Workshop; p 361-376
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  • 10
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A nylon separator was placed in a flooded condition in K0H solution and heated at various high temperatures ranging from 60 C to 110 C. The weight decrease was measured and the molecular weight and decomposition product were analyzed to determine: (1) the effect of K0H concentration on the hydrolysis rate; (2) the effect of K0H concentration on nylon degradation; (3) the activation energy at different K0H concentrations; and (4) the effect of oxygen on nylon degradation. The nylon hydrolysis rate is shown to increase as K0H concentration is decreased 34%, giving a maximum rate at about 16%. Separator hydrolysis is confirmed by molecular weight decrease in age of the batteries, and the reaction of nylon with molecular oxygen is probably negligible, compared to hydrolysis. The extrapolated rate value from the high temperature experiment correlates well with experimental values at 35 degrees.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 389-398
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  • 11
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Nylon separator degradation was examined as a function of temperature. Electrochemically active uncharged excess negative (overcharge protection)was measured by charging a cell venting it until it became fully charged, and continuing to overcharge the vent gas. The gas was analyzed as a function of time. The amount of hydrogen evolved was examined, and the cell voltage was observed as the oxygen and/or hydrogen evolved from the cell.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 345-354
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  • 12
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The modular power system, which is the first intended use for the NASA standard battery, is basically a four foot by four foot by eighteen inch box which can handle a complement of three 20 ampere hour batteries or later on the intended use is for three 50 ampere hour batteries to be the full complement. The system is designed to be used as a plug on component on a multi mission modular spacecraft. It has as a design point a basically 1250 watt orbital average load. The way it breaks up in a near earth orbit it would be somewhere around 1,000 watts for everything except 10 minutes, and during any 10 minute period it may go up to a peak of 3,000 watt load. Features of the battery reviewed include criteria to store electrical energy, the battery package, the covers and cases, and electrolytes. The capacities expected are 90 percent, the average cell capacity for 24 C, 90 percent of the actual battery capacity of 19 C, and 85 percent of the actual 25 degree battery capacity at zero discharge voltage for 50 percent DOD new battery is in the vicinity expected or predicted of 26.4 volts.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 437-450
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  • 13
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    In:  CASI
    Publication Date: 2006-06-13
    Description: A brief description of the ITOS power systems is presented. The descriptions are from viewgraphs shown to the participants of the Workshop. A block diagram of ITOS power supply subsystem is presented along with graphs representing: ITOS voltage limit versus temperature; and battery charge-discharge current profiles over an orbit period.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 7-13
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  • 14
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The results of an experiment to test storage effects on electric cells of a battery are presented and discussed. The type of cells were the 20 amp-hour OAO type. The various modes that were tested were the integration type mode, the trickle charge, the discharge shorted and the discharged OCV (open current voltage). Every six months the cells were reconditioned and approximately two weeks of tests were performed. The tests included three capacity checks, two zero-degree overcharge tests and an internal short test (the cells are shunted for 16 hours, the shunt removed and allowed to stand on local circuit recovery for 24 hours). The integration pack was discontinued after three years and the trickle charge shorted packs after five years.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 223-242
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  • 15
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    In:  CASI
    Publication Date: 2006-06-15
    Description: Some possible parameters which could be used to predict failures within packs of electrochemical cells based on measurements that are taken while the cells are cycling are discussed. Discharge and charge curves are presented and fitted to measure the efficiency of the cells in terms of voltage vs. time.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 181-195
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  • 16
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    In:  CASI
    Publication Date: 2006-06-15
    Description: A discussion is presented on the use of statistical analysis to develop a technique that will reliably predict the life of a battery.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 141-153
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  • 17
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    In:  CASI
    Publication Date: 2006-06-15
    Description: Prediction techniques are discussed for the cycle life of nickel cadmium space cells. Equations and graphs which incorporate such parameters as temperature and recharge are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 173-179
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  • 18
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    In:  CASI
    Publication Date: 2006-06-15
    Description: A brief discussion on the accelerated testing of batteries is given. The statistical analysis and the various aspects of the modeling that was done and the results attained from the model are also briefly discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 137-140
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  • 19
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    In:  CASI
    Publication Date: 2006-06-14
    Description: The orbit data for the Intelsat 4 spacecraft is described. The performance and characteristics of the battery used for this spacecraft are discussed. Graphs are presented which relate battery voltage to various eclipse seasons.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 89-107
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  • 20
    Publication Date: 2006-06-14
    Description: The OSO-1 represents a recent vintage satellite, or more recent design satellite. A summary of the battery design used on OSO-1 is presented. The temperature effects on voltage and charging-discharging of the battery system are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 43-54
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  • 21
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    In:  CASI
    Publication Date: 2006-06-14
    Description: Atmospheric Explorer (AE) is a 1971 power system design, using the heritage of the ITOS system. The system design and its operation are discussed. Problems of charging and discharging the batteries and the effects of temperature on these operations are discussed. A block diagram of the power supply electronics and some graphs related to voltage and temperature for the AE battery design are presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 15-23
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  • 22
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    In:  CASI
    Publication Date: 2006-06-14
    Description: A discussion is presented which gives an overview of the research and technological areas on nickel cadmium batteries at the Jet Propulsion Laboratory. Some of the topics covered include: goals; failure modes and mechanisms; factors of degradation and some possible solutions; energy density; and accomplishments for FY 77 and FY 78.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 119-132
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  • 23
    Publication Date: 2006-06-14
    Description: The battery was a three ampere hour nickel cadmium prismatic cell. The battery consists of 20 cells connected in series and there were two batteries per spacecraft. The battery operations (voltage and temperature) that the spacecraft sees during a normal operational day are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 69-79
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  • 24
    Publication Date: 2006-06-14
    Description: The battery design of OAO-C (OAO-3) is given and consists of three-20 ampere hour 22 series connected cells in the battery. There are three batteries per spacecraft. The packaging configuration is described. The charging-discharging operations and the voltage potential of the battery system are discussed. Graphs are presented for the voltage limits (battery voltage versus temperature) and end of dark voltages (battery voltage versus ampere-hours discharged) of the battery system used on OAO-3. Data tables are also presented which give a summary of the battery performance and a comparison of OAO-3 with OAO A-2.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 55-79
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  • 25
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Progress of four contractors in producing standard 20 AH nickel-cadmium cells meeting a capacity requirement of 24 + or - 2 AH and an envelope requirement listed in NASA/GSFC specification S-711-17 is reported. Among the requirements were 10 burn in cycles 24 C, 0 C, and 35 C capacity tests, charge efficiency tests and precharge verification tests.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 431-435
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  • 26
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Solar array power systems for the space construction base are discussed. Nickel cadmium and nickel hydrogen batteries are equally attractive relative to regenerative fuel cell systems at 5 years life. Further evaluation of energy storage system life (low orbit conditions) is required. Shuttle and solid polymer electrolyte fuel cell technology appears adequate; large units (approximately four times shuttle) are most appropriate and should be studied for a 100 KWe SCB system. A conservative NiH2 battery DOD (18.6%) was elected due to lack of test data and offers considerable improvement potential. Multiorbit load averaging and reserve capacity requirements limit nominal DOD to 30% to 50% maximum, independent of life considerations.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 451-461
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  • 27
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The graphite epoxy cell case and header developed as a means of weight reduction are discussed. Aspects considered include gas permeability, KOH compatibility, pressure and structural dynamic integrity, fiber orientation, fabrication process, cover-to-case sealing, terminal installation and sealing, reproducibility, exposure to the extractable materials that might influence the electrochemical portion of the cell, and electrical conductivity between the terminals.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 419-427
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  • 28
    Publication Date: 2006-06-14
    Description: A summary of the ATS battery design which is onboard the Applications Technology Satellite (ATS) is provided. The 15 ampere hour nickel cadmium cells were manufactured by Gulton, 19 series connected cells per battery, and there are two batteries in each spacecraft. The operating design life was two years in a synchronous orbit, and a maximum depth of discharge of 50 percent. The design temperature for the batteries in the spacecraft was 0 to 25 C, and the charge control consisted of 1 volt versus temperature on a constant percentage voltage. Also, C/10 current limit, and a commandable trickle charge rate, using C/20 or C/60. The undervoltage was sent across a 9 cell and a 10 cell group, and it was set at one volt average per group on either group.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 81-87
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  • 29
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    In:  CASI
    Publication Date: 2006-06-14
    Description: The operation and systems design of a nickel cadmium battery system used on the Nimbus and LANDSAT satellites are discussed. Emphasis is placed on the charging-discharging operation of the battery system.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 25-42
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  • 30
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Three 18 AH Li-CF batteries with a polypropylene separator and using dimethyl sulfite in Li as F6 for the electrolyte will be placed in each shuttle solid rocket booster for range safety and frustrum location aid. Mechanical vibration, acceleration, random and design vibration, and discharge evaluation tests are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 581-589
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  • 31
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Three lithium SO2 cells, two lithium CF cells, and a vinyl chloride cell, all with crimped seals, and all strictly experimental, were independently discharged on resistors. Three temperatures were used and several different storage temperatures. Discharge rate generally on the nominal discharges were 0.1 amp, 0.5 amp, and 1 amp. Tests results show that the crimp seals are inadequate, especially for the SO2 cells. Normal discharges present no hazards. All cells discharge to zero. The problem of lithium cell explosions, such as occurred during off-limits testing, is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 557-567
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  • 32
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The long duration exposure facility mission places temperature requirements of from -30 F to +150 F on the batteries to be used. A hermetically sealed lithium sulfur dioxide cell was tested to predict what the temperature of the battery would be over a given spectrum of temperatures of operation. Near the end of cell discharge, as the voltage started collapsing, a very high heat output rise due to chemical reaction took place. However, if the cells were thermally insulated, they vented, ignited, and burned if an attempt was made to discharge them all the way. The cells do not go into reversal. It was determined that the root of the problem was probably the chemical reaction between the lithium and the acetonitrite solvent. A redesigned cell is discussed as well as some alternates.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 565-580
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  • 33
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Experiences with batteries for the Apollo Soyuz Test Project are related and the need for safety criteria for space shuttle orbiter and payload battery handling and design is assessed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 545-556
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  • 34
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Because of the disintegration of LaNi5 as the lattice expands on absorbing hydrogen, a nickel hydrogen cell similar to a nickel cadmium cell was designed. The positive electrode is wrapped in a microporous separator and the leads are insulated. A negative conducting grid is inserted and welded to the top of the can into an open ended container which is then turned upside down and filled so that LiNa5 powder occupies all the space not used by the rest of the components. The bottom of the can is then welded on. A fill tube is located either on the bottom or on the top of the can. When welded shut, the cell is put into a pressure bomb and the lanthanum nickel is activated at about 1,000 pounds of hydrogen. Electrolytes are added to the cell as well as whatever amount of hydrogen precharge desired, and the cell is sealed. Advantages and disadvantages of the cell are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 533-543
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  • 35
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Values for the capacity loss with time, naturally on open circuit stand, and information regarding the minimum amount of circuit charge needed to keep the cell charged can be determined from the self-discharge behavior of nickel hydrogen cells. Furthermore, the rate of reaction between hydrogen and a charged nickel electrode is also open for nickel cadmium batteries. In a nickel hydrogen cell, the hydrogen is stored as pressurized gas and the cell stack with the charge that is oxidized nickel-hydroxide electrode is in direct contact with the hydrogen. Therefore, the rate of reaction can be measured easily and precisely by monitoring the charge, the change in hydrogen pressure with time. Measures made on twelve 15 ampere hour nickel hydrogen cells of different stack configurations built for COMSAT are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 525-531
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  • 36
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Design criteria are discussed for a hermetic seal capable of withstanding the 450 C operating temperature of a lithium-metal sulfide battery system. A mechanical seal consisting of two high strength alloy metal sleeves welded or brazed to a conductor assembly and pressed onto a ceramic is described. The conductor center passes through the ceramic but is not sealed to it. The seal is effected on the outside of the taper where the tubular part is pressed down over and makes contact.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 355-360
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  • 37
    Publication Date: 2006-05-22
    Description: The spectral thermal optimization of solar cell configurations for various solar panel applications is considered. The method of optimization depends upon varying the solar cell configuration's optical characteristics to minimize panel temperatures, maximize power output and decrease the power delta from beginning of life to end of life. Four areas of primary investigation are: (1) testing and evaluation of ultraviolet resistant coverslide adhesives, primarily FEP as an adhesive; (2) examination of solar cell absolute spectral response and corresponding cell manufacturing processes that affect it; (3) experimental work with solar cell manufacturing processes that vary cell reflectance (solar absorptance); and (4) experimental and theoretical studies with various coverslide filter designs, mainly a red rejection filter. The Hughes' solar array prediction program has been modified to aid in evaluating the effect of each of the above four areas on the output of a solar panel in orbit.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 127-132
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  • 38
    Publication Date: 2006-05-22
    Description: Normal isotopic silicon contains 3.05% of Si-30 which transmutes to P-31 after thermal neutron absorption, with a half-life of 2.6 hours. This reaction is used to introduce extremely uniform concentrations of phosphorus into silicon, thus eliminating the areal and spatial inhomogeneities characteristic of chemical doping. Annealing of the lattice damage in the irradiated silicon does not alter the uniformity of dopant distribution. Transmutation doping also makes it possible to introduce phosphorus into polycrystalline silicon without segregation of the dopant at the grain boundaries. The use of neutron transmutation doped (NTD) silicon in solar cell research and development is discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 109-116
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  • 39
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    In:  CASI
    Publication Date: 2006-05-22
    Description: A novel cover slide is reported which increases solar cell output by reducing the reflection of light from the cover slide surface and by redirecting incident light so that none falls on the collection grids of the cell. The new cover slide is fabricated with a sawtooth surface having a periodicity equal to that of the solar cell grids. This configuration refracts the light so that it is directed onto the semiconductor surface between the grid lines. Conventional grid patterns obstruct 7-10 percent of the light incident on the cell; at least half of this loss has been recovered by using the sawtooth cover slide. In addition, surface reflection from the conventional coated cover slide is suppressed by presenting a second surface to any light reflected at the first plane of contact. This double reflection results in a greater reduction of the reflection loss from the cover slide than does an antireflection coating on a flat surface.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 95-98
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  • 40
    Publication Date: 2006-05-22
    Description: Increased solar cell efficiencies are attained by reduction of surface recombination and variation of impurity concentration profiles at the n(+) surface of silicon solar cells. Diagnostic techniques are employed to evaluate the effects of specific materials preparation methodologies on surface and near surface concentrations. It is demonstrated that the MOS C-V method, when combined with a bulk measurement technique, yields more complete concentration data than are obtainable by either method alone. Specifically, new solar cell MOS C-V measurements are combined with bulk concentrations obtained by a successive layer removal technique utilizing measurements of sheet resistivity and Hall coefficient.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 69-79
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  • 41
    Publication Date: 2006-05-22
    Description: Quantitative analysis of the electron beam-induced current and the dependence of the effective diffusion length of the minority carriers on the penetration depth of the electron beam were employed for the analysis of the carrier recombination characteristics in heavily doped silicon layers. The analysis is based on the concept of the effective excitation strength of the carriers which takes into consideration all possible recombination sources. Two dimensional mapping of the surface recombination velocity of P-diffused Si layers will be presented together with a three dimensional mapping of minority carrier lifetime in ion implanted Si. Layers heavily doped with As exhibit improved recombination characteristics as compared to those of the layers doped with P.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 59-68
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  • 42
    Publication Date: 2006-05-22
    Description: Silicon and gallium arsenide solar cell developments are reviewed. The rationale for these efforts are cited showing the reasons for placing emphasis on survivability as well as high conversion efficiency.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 25-31
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  • 43
    Publication Date: 2006-05-22
    Description: One potential means of improving the efficiency of solar cells especially after space irradiation is to incorporate built-in fields into the device through the use of impurity doping gradients. A detailed numerical calculation of solar cell performance has been used to study various types of doping gradients. In general, the predicted improvements in performance have been less than previously reported due to various device effects such as, high injection and the dependence of lifetime on doping density.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 33-50
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  • 44
    Publication Date: 2006-05-22
    Description: Low cost solar cells and arrays with high end-of-life efficiency are evaluated through two approaches: one, to obtain increased device efficiency at no increase in cost and two, to reduce the manufacturing costs of space solar cells and arrays. Technology efforts encompass high efficiency epitaxial cells, high efficiency wraparound contact solar cells, economical diffusion sources, automated cell fabrication and development of easily applied, durable cover glasses. The examination of ion-implanted profile tailored junctions and additional development of screen printed contact technology to cell development are also considered.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 3-6
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  • 45
    Publication Date: 2006-05-22
    Description: Laboratory tests and flight experiments showed that solar cells can be produced in quantity, that they are suitable for space flight applications, and that the power produced ranged from 20 to 35% more than that of conventional cells. In a benign flight environment, the cells degraded at approximately the same rate as conventional cells. In synchronous orbit, the rate exceeded that of conventional cells, but high efficiency cells still showed significant power advantage after two years. Irradiation test results showed the voltage-temperature coefficients to be comparable to conventional cells. However, current-temperature coefficients were not only higher initially, but also increased significantly with irradiation. Although thin cells with good performance characteristics were made, significant problem areas pertinent to production were disclosed, particularly for cells with thickness of 0.100 mm or less. The overall program led to the use of advanced high efficiency cells on the International Sun-Earth Explorer solar panels.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 7-23
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  • 46
    Publication Date: 2006-05-24
    Description: Ultraviolet damage to the new violet and non-reflective type solar cell assemblies, was studied, and potential advantages of using coverslides with no filters or filters with cut-off wavelengths below 0.35 micron were determined. The experiments consisted of three types of tests on fused silica coverslides with 0.35- and 0.30-micron cut-off filters and no cut-off filters, as well as on ceria-doped microsheet coverslides. Ultraviolet irradiation for over 1500 hours at one sun conditions (AMO) was carried out under vacuum of about 1 million torr. Nearly identical results for non-reflective type cells with 0.35-micro cut-off filters or ceria-doped coverslides were obtained. The 0.30-um filtered cell shows greater than average degradation. The unfiltered cell shows an abrupt drop in the first 20 UVSH and very little subsequent degradation.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 227-229
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  • 47
    Publication Date: 2006-05-24
    Description: Close examination of the interaction of the energetic knock-on atoms with the local lattice environment reveals a damage mechanism which does satisfy the experimental data on proton irradiation of silicon. A proton-atom interaction with high energy transfer is considered where the proton path is delineated by a trail of ionization, and the silicon ion path is characterized by much heavier ionization terminating in a dense displacement cluster. At collision, many of the silicon electrons are stripped off, and the resulting energetic ion subsequently loses energy rapidly by Coulomb interaction with bound electrons. The rate of energy loss depends on the charge state and velocity of the knock-on ion. For ion energies in excess of 1 MeV, the intensity of ionization is sufficient to permit lattice atoms, stripped of their binding electrons, to reorient randomly before having an opportunity to recombine with electrons and re-establish the lattice. The path of a knock-on ion thus becomes a thin cylinder of amorphous material within the crystal. Amorphous silicon has a Fermi level closer to mid-band than does single crystal silicon, and a strong field therefore, results around this damaged region. The field produces a large depletion region, representing a very large capture cross section for minority carriers.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 221-223
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  • 48
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    In:  CASI
    Publication Date: 2006-05-24
    Description: The motivation for developing GaAs solar cells is based on their superior efficiency when compared to silicon cells, their lower degradation with increasing temperature, and the expectation for better resistance to space radiation damage. The AMO efficiency of GaAs solar cells was calculated. A key consideration in the HRL technology is the production of GaAs cells of large area (greater than 4 sg cm) at a reasonable cost without sacrificing efficiency. An essential requirement for the successful fabrication of such cells is the ability to grow epitaxially a uniform layer of high quality GaAs (buffer layer) on state-of-the-art GaAs substrates, and to grow on this buffer layer the required than layer of (AlGa)As. A modified infinite melt liquid phase epitaxy (LPE) growth technique is detailed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Lewis Res. Center Solar Cell High Efficiency and Radiation Damage; p 149-157
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  • 49
    Publication Date: 2006-05-24
    Description: A new double graded band-gap (DGBG) Al sub x Ga sub l-x As-Al sub z Ga sub l-z As solar cell has potential for providing high efficiency performance throughout the entire life of a solar cell in a space environment. A preliminary theoretical analysis indicates that short circuit current available from an optimized DGBG cell is slightly larger than that of a previously reported single graded band-gap cell. However, the DGBG cell potentially offers a substantial improvement in radiation resistance of the base region.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 139-147
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  • 50
    Publication Date: 2006-05-24
    Description: The present status of the GaAlAs/GaAs heteroface solar cell program is reported. Studies have been concentrated on GaAlAs/GaAs heteroface solar cells; however, some research has been conducted on thin junction, diffused GaAs solar cells. Emphasis has been on obtaining high efficiency (18% to 20%) GaAs solar cells. Two problems that have limited the efficiency of GaAs solar cells are the high recombination velocity of carriers near the surface and the low minority carrier diffusion length in n-GaAs.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Cell High Efficiency and Radiation Damage; p 133-138
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  • 51
    Publication Date: 2006-01-12
    Description: Problems encountered on Skylab prompted the development of a reconditioning circuit which involves a DC to DC converter, a circuit sensing device, and the capability of switching several size reconditioners onto a circuit. Across each cell there is a full bridge rectifier. During battery discharge, if there is low cell voltage, the reconditioning systems holds that voltage up and permits discharge to continue on the system. When the cell is good, the voltage is up about one volt, the diodes are back, or reversed biased, and the current drawn out of the system is very low. The system has a standby power thrown at about one volt. As the voltage drops on a cell, the circuit strts picking up the load and helps hold the overall battery voltage up.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 305-313
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  • 52
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-01-12
    Description: Various steps followed in analyzing the electrolyte, separator, and electrodes are reviewed. Specific emphasis is given to scanning electron microscopic and metallographic analysis of the plates. Cadmium migration is defined, its effects and causes are examined, and methods for its reduction in cells are suggested.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 377-388
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  • 53
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A discussion on cell reversal during flight is presented. Data tables and graphs are also presented to clarify the discussion.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 285-292
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  • 54
    Publication Date: 2006-06-18
    Description: A mechanism which allows a cell voltage reversal in a nickel cadmium battery are discussed. The effects of reconditioning and the characteristics of Ni-Cd cells during voltage reversal at low overdischarge rates are outlined. Graphs are presented for: (1) hydrogen pressure decay-effect of state of charge (open circuit stand); (2) hydrogen pressure increase during overdischarge; (3) hydrogen pressure decay-effect of temperature (cells terminals connected through resistors); (4) cell, positive and negative electrode voltage during reversal when reconditioning a 13 cell-24-Ah battery pack through a 40 Omega resistor; (5) pressure discharge current and recombination current during voltage reversal when reconditioning a 13 cell-24-Ah battery pack through a 40 Omega resistor; (6) theoretical hydrogen gas pressure if there were no recombination; and (7) effect of hydrogen pressure on recombination rate during overcharge.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 271-283
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  • 55
    Publication Date: 2006-06-15
    Description: Some real life data on the flight performance and reconditioning on the Communications Technology Satellite are presented. There are two 24-cell nominal 5 amp-hour nickel cadmium batteries on board. The two batteries are operated in parallel with isolating diodes in between and permanently connected to the housekeeping buses. The recharge can be at C over 10 or C over 20 to a 1.4 charge/discharge ratio; and recharge is terminated either when a computed 1.4 charge/discharge ratio is reached, or a charge voltage peak is reached.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 245-257
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  • 56
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-15
    Description: The long-term effects of storing batteries over a period of years prior to their use in a synchronous orbit application are discussed. A previous experiment is discussed where life testing was performed on cells after having stored the battery for a period of three years with the cell shorted and at a temperature on the order of 5-10 C. The test consisted of performing a sequence of 10 simulated eclipse seasons (equivalent in cycling of five years in synchronous orbit). Results of this test indicated very little degradation and change in the physical and chemical conditions of the cell. The program was extended for an additional year (battery was stored for four years) under the same conditions and testing. The results of the four year storage (one exception) indicate that no further change occurred that is significant from the three year test.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 219-222
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  • 57
    Publication Date: 2006-06-15
    Description: An engineering evaluation of the Multimission Modular Spacecraft power supply is presented. The spacecraft has one charger with eight commandable voltage versus temperature levels. Graphs are presented which represent: (1) cell voltage limits vs. temperature; (2) charge ratio vs. temperature; (3) effect of 0.0 percent impedance unbalance at 10 C; (4) shorted cell at 10 C; and (5) discharge voltage profile at 10 C.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 197-211
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  • 58
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A typical 625 Inconel pressure vessel, equipped with four thermocouples, has voltage taps not only for the cell, but for each of the several packs inside the container. In a two-stack design, a weld ring is used to separate the packs which, joined together, form one solid group. In the four-stack design, stacks are separated mechanically with about half inch Plexiglas and are connected through the center. Electrolytes are forced out by vacuum. The two stack design is intended for 500 psi and was pressure tested up to 1,000. The problem of electrolyte shorts is discussed and possible solutions for its correction are given.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 519-524
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  • 59
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: A brief history of the SATCOM satellites is given. Cell design and battery operating characteristics are outlined and discussed. Graphs are presented comparing reconditioning parameters such as voltage, temperature, time and discharge.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 293-304
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  • 60
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Periodic capacity checks are assessed as well as the effects of periodic discharges on the cycle life and the performance of cells during the cycle life. Topics discussed include the effect of the amount of electrolyte on cell capacity at 35 C; battery design for spacecraft; electrolyte starvation theory; battery separator degradation; negative electrode stability; voltage regulation; operating temperatures; and integration of reconditioning systems using microprocessors.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The 1977 Goddard Space Flight Center Battery Workshop; p 315-343
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  • 61
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Results of cyclic tests on seven 3-cell 100 A-H nickel cadmium batteries on 1.5 hr cycles are presented. The failure of the nylon and polypropylene separators was not analyzed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 475-478
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  • 62
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The capabilities of photovoltaic, nuclear reactor, and solar thermal systems are assessed for the space construction base. Topics covered include Brayton conversion, thermionic conversion, and thermo-electric conversion. The effectiveness of nickel cadmium and nickel hydrogen batteries are discussed as well as that of regenerative fuel cells. The verification of long cycle life for nickel hydrogen systems is recommended.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 463-474
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  • 63
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: Batteries designed for the defense satellite communications system were modified to meet increased power requirements. A stainless steel case for the cell, approximately 4 inches wide, 4 1/2 inches high and 1 inch thick, with a weld down a narrow edge, has 12 mil 304-L stainless steel side walls and a 19 mil 304-L stainless bottom. A dip-brazed 60-61 aluminum retainer is electrically separated from the steel case by 15 mils of potting compound. The thickness of the compound varies from 10 to 20 mils, except at the bottom, where it is 20 to 30 mils thick. Pressure test results are discussed.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 409-417
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  • 64
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-06-18
    Description: The thickness, moisture content, exchange capacity, tensile strength, diffusion characteristics, stability, and electrical properties are discussed for the 2291 radiation-grafted separator used in military vented nickel cadmium aircraft batteries. A regression analysis of separator resistance as a function of temperature and KOH concentration is included.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Goddard Space Flight Center The 1977 Goddard Space Flight Center Battery Workshop; p 399-408
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  • 65
    Publication Date: 2011-08-17
    Description: Radio tracking data associated with the February 1977 encounters between the Martian satellite Phobos and the Viking Orbiter I spacecraft have been analyzed to determine the gravitational constant of Phobos. A linear error analysis was conducted to determine the selection of data and the parameter solution set which would yield the best estimate of the gravitational constant. This error analysis indicated that the optimal data set was a data arc beginning just prior to the closest encounter and spanning three consecutive spacecraft orbits; data near periapsis were deleted. The most feasible parameter solution set consisted of the Phobos gravitational constant and the spacecraft initial conditions. The result of the data analysis was an estimate of (7.3 plus or minus 0.7) x 10 to the -4th cu km/sq sec for the gravitational constant of Phobos.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters; 4; Dec. 197
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  • 66
    Publication Date: 2011-08-17
    Description: The spectral radiance and color of the Martian sky and soil and the spectral reflectance of soil features are estimated from six-channel (0.4-1.0 micron) spectral data obtained with the Viking lander cameras. Images taken near local noon from the two landers reveal a sky that is brighter near the horizon than the soil but with a similar spectral radiance shape and color. The scenes are predominantly moderate yellowish brown in color with only subtle variations except for some dark grey rocks. Most spectral reflectance estimates are similar: they rise rapidly with increasing wavelength between 0.4 and 0.8 micron and with only a few exceptions exhibit a pronounced minimum centered about 0.93 micron. These characteristics are consistent with an abundance of Fe(3+)-rich weathering products, notably nontronite. However, the delineation of the number and abundances of total mineral phases requires further analyses and laboratory comparisons. Reflectance estimates for rocks have not been repeatable, probably because most rocks have irregular pitted surfaces that introduce significant shadowing components.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 82; Sept. 30
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  • 67
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    Publication Date: 2011-08-17
    Description: Observations of hydroxyl (OH) emission from meteors were made during the late summers of 1975 and 1976 from altitudes of 10,600 and 14,200 feet (3.2 km and 4.45 km). The observations were made with OH meteor photometers developed at the NASA-Langley Research Center. Two of the meteors were Perseids, and one was an Alpha Capricornid. The Perseid meteors produced a peak irradiance at a distance of 100 km from the meteors of about 0.00005 erg/sq cm per sec in the OH emission region. The zero-magnitude Alpha Capricornid meteor produced a spectral irradiance at 3100 A of 23 hundred-millionths erg/sq cm per A per sec. This may be indicative of significant amounts of H2O in these meteors.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astrophysical Journal; vol. 217
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  • 68
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    Publication Date: 2011-08-17
    Description: It has been suggested that NH3 and other reducing gases were present in the earth's primitive atmosphere, enhancing the global greenhouse effect; data obtained through isotopic archeothermometry support this hypothesis. Computations have been applied to the evolution of surface temperatures on Mars, considering various bolometric albedos and compositions. The results are of interest in the study of Martian sinuous channels which may have been created by aqueous fluvial errosion, and imply that clement conditions may have previously occurred on Mars, and may occur in the future.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature; 269; Sept. 15
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  • 69
    Publication Date: 2011-08-17
    Description: Mineralogical and chemical characteristics of the Happy Canyon meteorite, found in 1971 near Wayside, Texas, show it to be a new type of enstatite achondrite occupying the gap between the recrystallized enstatite chondrites and the igneous, crystalline, unbrecciated enstatite chondrites. Although the bulk composition of the specimen is consistent with that of an E6 enstatite chondrite, it has a crystal cumulate texture. There are minor amounts of metal and troilite which have survived extensive weathering. The Happy Canyon meteorite may represent an E6 composition which has melted and reprecipitated at a slightly higher oxidation state, possibly in the core of a small parent body.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics; 12; June 30
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  • 70
    Publication Date: 2011-08-17
    Description: Photoionization of the upper atmosphere of Titan by sunlight is expected to produce a substantial ionospheric layer. One-dimensional forms of the mass, momentum, and energy conservation equations for ions and electrons have been solved along with electron number densities of about 1000/cu cm, using various model atmospheres. The significant ions in a CH4-H2 atmosphere are H(+), H3(+), CH5(+), CH3(+), and C2H5(+). Electron temperatures may be as high as 1000 K, depending on the abundance of hydrogen in the high atmosphere. Interaction of the solar wind with the ionosphere is also discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 31; May 1977
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  • 71
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    Publication Date: 2011-08-17
    Description: A description is given of the observation of five brief occultations of the star SAO 158687 which occurred both before and after its occultation by Uranus on March 10, 1977. The events were observed with a three-channel occultation photometer, attached to a 91-cm telescope. The observations indicate that at least five rings encircle the planet Uranus. Possible reasons for the narrowness of the Uranus rings are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Nature; 267; May 26
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  • 72
    Publication Date: 2011-08-17
    Description: Until recently, the majority of work in geothermal energy development has been devoted to technical considerations of resource identification and extraction technologies. The increasing interest in exploiting the variety of geothermal resources has prompted an examination of the institutional barriers to their introduction for commercial use. A significant effort was undertaken by the Jet Propulsion Laboratory as a part of a national study to identify existing constraints to geothermal development and possible remedial actions. These aspects included legislative and legal parameters plus environmental, social, and economic considerations.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Nuclear Technology; 34; June 197
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  • 73
    Publication Date: 2011-08-17
    Description: Two nightside encounters with Mercury's magnetosphere by Mariner 10 revealed bow shock and magnetosheath signatures in the plasma electron data that are entirely consistent with the geometry expected for an interaction between a planet-centered magnetic dipole and the solar wind. The geometrically determined distance between the planet's center and the solar wind stagnation point is 1.4 plus or minus 0.1 R sub M. Both diffuse and sharp shock crossings were observed on the two magnetosphere encounters.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 82; May 1
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  • 74
    Publication Date: 2011-08-17
    Description: Twenty-two light curves of Hebe are analyzed along with results of UBV photometry and photometric astrometry. A mean synodic period of approximately 7 hr 16 min 28.7 sec is adopted, and it is found that the amplitude of Hebe appears to vary directly with phase. The asteroid's magnitudes and colors are plotted against phase, its pole orientation is estimated, and the sidereal period is determined to be about 7 hr 16 min 28.01 sec from photometric astrometry. A color curve is plotted which shows that Hebe has a reddened region on its surface near the secondary minimum and that the asteroid is nearly spherical. Opposition effects are compared and found to be closely similar for Hebe, Ceres, Lydia, Massalia, and Vesta.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomical Journal; 82; Mar. 197
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  • 75
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    Publication Date: 2011-08-17
    Description: Basic data are presented on the Del Rio, Nordheim, and Monahans ataxites found in Texas. Results are reported for bulk-chemistry analysis, metallographic observations, and electron-microprobe analysis of the Del Rio meteorite. It is shown that Del Rio is distinctly different from the other two ataxites in terms of nickel, phosphorous, and carbon content, and is composed of at least three coarse grains in different crystallographic orientations. All the kamacite in Del Rio is found to have transformation structures that are probable shock products, and minor inclusions of daubreelite, schreibersite, and troilite are observed. It is concluded that Del Rio was apparently mildly shocked prior to its fall.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics; 12; Mar. 31
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  • 76
    Publication Date: 2011-08-17
    Description: The development and application of a variable composition solar cell computer analysis program is discussed. The basic device equations are derived and results of the computer analysis of several Al(x)Ga(1-x)As and GaAs(1-x)P(x) solar cell structures are presented along with a discussion of the effects of interface states and various composition and doping profiles on maximum solar cell efficiency. Interface states are found to be responsible for a severe reduction in the efficiency of GaAs(1-x)P(x) cells, but do not significantly affect the behavior of Al(x)Ga(1-x)As cells. The depth of the p-n junction below the wide bandgap window layer is a critical factor in determining the loss of minority carriers to interface recombination at the heterojunction.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-24; Apr. 197
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  • 77
    Publication Date: 2011-08-17
    Description: Effects of collisions and finite winds characteristic of a highly perturbed atmosphere on the thermal escape of terrestrial hydrogen and helium are investigated using a Monte Carlo approach. The limiting cases of vertical and horizontal winds are considered, and the relaxation layer between the collisionless exosphere and the collision-dominated thermosphere is modeled as a plane-parallel slab of given column density, depth, and atmospheric density. For both gases, the upwardly injected flux at the base of the relaxation layer is compared with the returning downward flux distribution at the same location; the technique is also applied to the atmosphere of Titan. The results show that inclusion of collisions in the escape model for terrestrial hydrogen with winds effectively throttles the escape process, that collisional throttling is negligible for helium when the exobase temperature is at least 5000 K, and that the escape of a planetary-atmosphere constituent depends on the ratio of its gravitational and kinetic energies as well as on the ratio of its mass to that of the background gas.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 82; Mar. 1
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  • 78
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    Publication Date: 2011-08-17
    Description: Over one thousand occultations of each planet in the solar system have occurred during the period from mid-1973 through mid-1976 as seen from the lunar orbiting Radio Astronomy Explorer 2 (RAE 2) spacecraft. These occultations have been examined for evidence of planetary radio emissions in the 0.025-13.1 MHz band. Only Jupiter and the earth have given positive results. Lack of detection of emission from the other planets can mean that either they do not emit radio noise in this band or the flux level of their emissions and/or its occurrence rate are too low to be detected by RAE 2.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 82; Mar. 1
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  • 79
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    Publication Date: 2011-08-17
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 195; Mar. 11
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  • 80
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    Publication Date: 2011-08-17
    Description: The article presents a rebuttal of Young's (1975) view that the 140 m/sec horizontal wind at 45 km reported by Venera 8 is anomalous or spurious. Some errors are discussed and the largest contribution is attributed to descent probe measurements designed to find the true probe descent rate. Young's suggestion of error in in situ measurement of winds due to selection of a reference speed and to unrecognized oscillator drift is scrutinized. Evidence is seen for a wide band of variable high-grade retrograde horizontal winds girdling Venus at the equator. Mariner 10 evidence (UV photographs) is taken into account. The band of winds at 45 km is seen to extend well beyond the top of the visible cloud, and an upper turbulent region is attributed to vertical convection currents carried along by high-speed horizontal winds.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 30; Feb. 197
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  • 81
    Publication Date: 2011-08-17
    Description: A comparison is made of the cost and thermal efficiency of producing liquid hydrogen, liquid methane and synthetic aviation kerosene from coal. These results are combined with estimates of the cost and energy losses associated with transporting, storing, and transferring the fuels to aircraft. The results of hydrogen-fueled and kerosene-fueled aircraft performance studies are utilized to compare the economic viability and efficiency of coal resource utilization of synthetic aviation fuels.
    Keywords: ENERGY PRODUCTION AND CONVERSION
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  • 82
    Publication Date: 2011-08-17
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 32; Sept
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  • 83
    Publication Date: 2011-08-17
    Description: Assuming that the solar wind plasma is usually nonuniform over distances of 10,000 km or less, it is shown that filamentary plasma elements stretched out from the sun can penetrate impulsively and become engulfed into the magnetosphere. The diamagnetic effects associated with these plasma inhomogeneities are observed in outer magnetospheres and magnetosheaths as dips or directional discontinuities in the magnetic field measurements. From the mean penetration distances of these diamagnetic plasma elements one can deduce a mean deceleration time, as well as an approximate value of the integrated Pedersen conductivity in the polar cusp of the earth and Jupiter.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Planetary and Space Science; 25; Sept
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  • 84
    Publication Date: 2011-08-17
    Description: An attempt is made to report on experiments in which a molecular-weight increase was determined in thin layers of triglyceride-containing glycerides after thin-layer contact for two years with lunar topsoil grains at 25 C without any thermal activation. It is noted that solidification was observed on both dielectric grains and metal-rich areas and that changes in viscosity and molecular weights were first detected by solidification of surface layers. Gel permeation chromatography is described which detected a general shift of the Gaussian distribution of the molecular-weight data toward generally higher molecular weights as well as an increase in mean molecular weight. Reaction mechanisms are considered, and results of spectrographic analysis are cited which support the interpretations of the molecular-weight data.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: The Moon; 16; May 1977
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  • 85
    Publication Date: 2011-08-17
    Description: The tentative detection of a methane line in emission at 76.2 GHz in the atmosphere of Jupiter is reported. The observed feature is well-correlated with the presence and absence of Jovian decameter-emission activity on successive days. The present results may represent the first detection of extraterrestrial methane microwave emission.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astrophysical Journal; vol. 216
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  • 86
    Publication Date: 2011-08-17
    Description: Heliostat designs intended to reduce costs and the effect of adverse wind loads on the devices were developed. Included was the low-profile heliostat consisting of a stiff frame with sectional focusing reflectors coupled together to turn as a unit. The entire frame is arranged to turn angularly about a center point. The ability of the heliostat to rotate about both the vertical and horizontal axes permits a central computer control system to continuously aim the sun's reflection onto a selected target. An engineering model of the basic device was built and is being tested. Control and mirror parameters, such as roughness and need for fine aiming, are being studied. The fabrication of these prototypes is in process. The model was also designed to test mirror focusing techniques, heliostat geometry, mechanical functioning, and tracking control. The model can be easily relocated to test mirror imaging on a tower from various directions. In addition to steering and aiming studies, the tests include the effects of temperature changes, wind gusting and weathering. The results of economic studies on this heliostat are also presented.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 19; 4, 19; 1977
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  • 87
    Publication Date: 2011-08-17
    Description: The current state of knowledge of the Venusian clouds is reviewed. The visible clouds of Venus are shown to be quite similar to low level terrestrial hazes of strong anthropogenic influence. Possible nucleation and particle growth mechanisms are presented. The Pioneer Venus experiments that emphasize cloud measurements are described and their expected findings are discussed in detail. The results of these experiments should define the cloud particle composition, microphysics, thermal and radiative heat budget, rough dynamical features and horizontal and vertical variations in these and other parameters. This information should be sufficient to initialize cloud models which can be used to explain the cloud formation, decay, and particle life cycle.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; May 1977
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  • 88
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    Publication Date: 2011-08-17
    Description: Mission timetables, spacecraft, scientific objectives, and payloads of the two mission, Orbiter and Multiprobe, planned for launch and encounter with Venus during the 1978 Venus mission opportunity are described. Basically, the Orbiter mission has the goal of global mapping of the clouds, atmosphere and ionosphere of Venus by remote sensing and radio occultation, global studies by in situ measurements of the upper atmosphere and ionosphere and solar wind-ionosphere interaction region, and determination of gravitational field harmonics from perturbations of the spacecraft orbit. The Multiprobe mission will study the nature and composition of the clouds, the structure of the atmosphere, the circulation pattern, and the characteristics of the planetary environmental interaction with the solar wind.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; May 1977
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  • 89
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    Publication Date: 2011-08-17
    Description: The paper outlines the evolution of the Pioneer Venus program from the initial meeting of a consortium of scientists to study the feasibility of a simple entry probe to Venus, through the Planetary Explorer missions, to the Orbiter Mission proposals. Major recommendations of the 1970 National Academy of Sciences study on Venus exploration planning and of the 1972 Pioneer Venus Science Steering Group report are mentioned.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; May 1977
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  • 90
    Publication Date: 2011-08-17
    Description: Some of the main questions regarding the composition, structure, and origin of the atmosphere of Venus are posed. These questions are (1) the distribution of the constituents of the lower atmosphere, (2) cloud composition, (3) the planet's surface and interior as revealed by atmospheric data, (4) the state property profiles and their variation over the planet, (5) the reason for the high temperatures of the lower atmosphere, (6) composition and temperature profiles of the upper atmosphere and location of the homopause, (7) spatial and temporal variations in the upper atmosphere, (8) the cause of the stability of CO2 - global circulation or local turbulence, (9) influence of neutral composition on the thermal structure, (10) response of upper atmosphere to change in solar EUV and solar wind, (11) the source and destination of the atmosphere, and (12) the location of Venus's water. The main parameters to be measured which will aid in resolving these problems are enumerated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; May 1977
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  • 91
    Publication Date: 2011-08-17
    Description: The present knowledge of Venus is reviewed with discussions of the nature and history of both the surface, crust and interior. Instrumentation on board the Pioneer Venus Orbiter, including the radar mapper, radio tracking and the fluxgate magnetometer, is described. Topographic, geological, Bouguer gravity, magnetic, and crustal thickness maps will be constructed from Orbiter data. These maps should provide information on composition and thermal history, the major geological or geophysical provinces, the rate of past and present tectonic activity, and evidence of past or present MHD dynamos.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; June 197
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  • 92
    Publication Date: 2011-08-17
    Description: The current state of knowledge of the chemistry, dynamics and energetics of the upper atmosphere and ionosphere of Venus is reviewed together with the nature of the solar wind-Venus interaction. Because of the weak, though perhaps not negligible, intrinsic magnetic field of Venus, the mutual effects between these regions are probably strong and unique in the solar system. The ability of the Pioneer Venus Bus and Orbiter experiments to provide the required data to answer the questions outstanding is discussed in detail.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; June 197
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  • 93
    Publication Date: 2011-08-17
    Description: Current knowledge of the temperature structure of the atmosphere of Venus is briefly summarized. The principal features to be explained are the high surface temperature, the small horizontal temperature contrasts near the cloud tops in the presence of strong apparent motions, and the low value of the exospheric temperature. In order to understand the role of radiative and dynamical processes in maintaining the thermal balance of the atmosphere, a great deal of additional data on the global temperature structure, solar and thermal radiation fields, structure and optical properties of the clouds, and circulation of the atmosphere are needed. The ability of the Pioneer Venus Orbiter and Multiprobe Missions to provide these data is indicated.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; June 197
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  • 94
    Publication Date: 2011-08-17
    Description: With the possible exception of the lowest one or two scale heights, the dominant mode of circulation of Venus' atmosphere is a rapid, zonal, retrograde motion. Global albedo variations in the ultraviolet may reflect planetary scale waves propagating relative to the zonal winds. Other special phenomena such as cellular convection in the subsolar region and internal gravity waves generated in the interaction of the zonal circulation with the subsolar disturbance may also be revealed in ultraviolet imagery of the atmosphere. We discuss the contributions of experiments on the Orbiter and Entry Probes of Pioneer Venus toward unravelling the mystery of the planet's global circulation and the role played by waves, instabilities and convection therein
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Science Reviews; 20; June 197
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  • 95
    Publication Date: 2011-08-17
    Description: Models of the ionospheres of Saturn, Uranus, and Neptune are presented. It is postulated that galactic cosmic-ray ionization is an important component of these ionospheres. For example, in the case of Neptune, the level of ionization caused by cosmic rays is comparable with that due to solar extreme-ultraviolet (EUV) radiation. The existence of cosmic-ray, as well as solar EUV-produced ionization, could be a valuable diagnostic tool for investigating the atmospheric thermal structure of those planets.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astrophysical Journal; vol. 215
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  • 96
    Publication Date: 2011-08-17
    Description: More than 1400 observations of lunar transient phenomena (LTP), encompassing brightenings, darkenings, and gaseous, reddish, and bluish events, are analyzed in an attempt to determine the possible causes of LTP. Hypotheses considered include effects of earth tides on the moon, low-angle illumination, thermal luminescence, UV heating, solar-particle acceleration by the magnetopause of earth's magnetotail, terrestrial magnetotail bow-shock-front turbulence, cathode luminescence due to magnetotail effects, and solar-flare particle bombardment. Analysis are performed in terms of histograms of the number of observations vs. phase of anomalistic period and of number vs. moon's age, percentage of numbers of observed phenomena and percentage of expected numbers as well as their ratios, and albedo behavior over a lunation period of chosen permanent points in ten specific features. The results indicate that different phenomena may have different causes, strong tidal effects are dubious, correlations with sunrise are most frequent, and the distribution of all LTP sites is distinct from that of deep- and shallow-focus moonquake epicenters.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 97
    Publication Date: 2011-08-17
    Description: Analysis of light curves and UBV photometry yields a model for (7) Iris as an ellipsoid with axial ratios 3:4:5. The North Pole orientation is near 41 deg ecliptic latitude and 11 deg longitude.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Astronomical Journal; 82; June 197
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  • 98
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    Publication Date: 2011-08-17
    Description: Spin-scan images of Ganymede obtained by the imaging photopolarimeter of Pioneer 10 in December 1973 are described and presented. Intensity measurements in the blue and red scans are provided. The width of the scan elements is 0.5 mrad which is the size of the aperture in the focal plane of the telescope; the height is also 0.5 mrad (1 millisec integration - or dwell-time at 5 rpm spin rate). The distance of Pioneer 10 from Ganymede was 7.8 x 10 to the fifth km, and the resolution is therefore 390 km. The spin-scan image is in general agreement with Lyot's visual observations (Dollfus, 1961). Preliminary results on polarimetry of Ganymede obtained during the flyby of Pioneer 10 are discussed with attention to the question of whether water frost, NaCl powdered crystals, or other substances is responsible for the observed pattern.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 99
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    Publication Date: 2011-08-17
    Description: Ground-based and spacecraft observations of Phobos and Deimos are reviewed and the satellites' origin is discussed. The crater densities of both bodies are close to the saturation level. The largest impact events may have caused extensive fracturing of their surfaces. The surfaces are at least 1.5 billion years old and may date back to the early history of the solar system. The Martian satellites display large deviations from sphericity. As a result of tidal processes, they are in synchronous rotation. Several independent lines of evidence show that they have regoliths. Despite some provocative arguments, their internal strengths and the nature of their interior are poorly known at present. Photometric measurements suggest that they are made of either carbonaceous chondritic material or a basalt. Sinclair (1972), Born and Duxbury (1975) and Shor (1975) apparently have successfully determined Phobos' secular acceleration. Their value of approximately .001 deg/year/year implies that the interior of Mars has a low specific dissipation factor (about 100), may indicate that a portion of the Martian interior is experiencing partial melting. The low inclination of the satellites' orbits indicates that they were formed as part of the same process that resulted in Mars.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 100
    Publication Date: 2011-08-17
    Description: Surface properties of lunar fines sample 67481 have been investigated by measuring the adsorptions of nitrogen (at -196 C) and water (at 20 C). Characteristics of this sample are similar to those of samples from other locations on the lunar surface and include the more typical alteration reaction with adsorbed water. Although their maturities are markedly different, the surface properties of 67481 are very much like those of the more mature 63341 from the adjacent station 13. These results indicate that the surface properties of lunar soils attain an equilibrium state faster than other properties used to indicate maturity.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Earth and Planetary Science Letters; 35; 1, Ma; May 1977
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