Abstract: This paper summarizes the results of study to determine the effects of space plasmas on a large GaAs solar cell array using solar reflectors at a concentration ratio of 2 in Geostationary orbit. The configuration studied was an early Rockwell International SPS. It was concluded that the system could ATTACHMENT : function in the GEO environment if certain design changes were implemented. These included conductive coatings on the solar cells, changing the reflector material from Kapton to a higher conductivity material and oversizing the array to compensate for a 0.7/ parasitic load due to losses from the ambient magnetospheric plasma. The study also looked at the operation of the solar powered Earth Orbit Transfer Vehicle in LEO and concluded severe arcing would take place on all high voltage negative portions of the array. The parasitic load loss at LEO was estimated at 3Z. Operation of a high voltage array at LEO represents a major problem. Charge exchange ion feedback from argon ion thrusters located near the EOTV solar array was also examined and all problems found were bel ieved to be solvable by the placement of protective ground screens. Title: High power requirements Source: Proceedings of the AFOSR Special Conference on Prime-Power for High Energy Space Systems, Norfolk, Virginia, USA, Feb. 22-25, 1982. (Paper No. 1-3) Authors: Cohen, M. E.; Keywords: solar cells, nuclear, onboard power storage and distribution, SPS general , Abstract: Military spacecraft missions in the communication, navigation and meteorological areas currently require power in the general neighborhood of 1-2 KW. This is expected to grow moderately to 5-15 KW by the 1990's due to onboard data processing, enhanced communication cross-linking, increased on- ATTACHMENT : station housekeeping requirements and higher powered downlink transmitters to support the increased use of small and diversified ground communication facilities. Title: Power from radiant-energy sources: an overview Source: Proceedings of the AFOSR Special Conference on Prime-Power for High Energy Space Systems, Norfolk, Virginia, USA, Feb. 22-25, 1982. (Paper No. VI-1) Authors: English, Robert E.; Brandhorst, Henry W., Jr.; <NASA - Lewis Research Center, Cleveland, Ohio) Keywords: space energy conversion, lasers, solar cells, microwaves, materials and coatings, nuclear, thermal control, Abstract: Radiations from the Sun, from microwaves and from lasers are assessed as energy sources for electric power in space. Recent advances in photovoltaic technology have improved the radiation resistance of silicon solar cells and substantially reduced their annealing temperature. Advances in GaAs arrays ATTACHMENT : include the featherweight CLEFT cell and lightweight blankets based on this cell. Use of the 100X miniature cassegranian concentrator is compatible with silicon, GaAs and advanced solar cells and not only reduces array cost but also raises efficiency and increases radiation tolerance. Advanced concepts to raise efficiency above 0.3 are also discussed. Parabolic mirrors could focus and collect either sunlight or laser radiation at high efficiency. From such heat sources at 1700-2200 K, several competitive concepts can generate electric power. Power can reach 30 kW/m<m) of radiator area or, alternatively, efficiency can exceed 50Z. For microwave power transmission over geostationary distances, wavelength must be reduced to 0.1 mm <by a factor of 1000) if collector area is to improve substantially over that of sunlit photovoltaic arrays. Lasers matched in wavelength to GaAs photovoltaic arrays appear capable of providing electric power exceeding 1 kW/kg of array mass. Title: High efficiency Tandem or Cascade photovoltaic solar cells for space app1 i cat i on Source: Proceedings of the AFOSR Special Conference on Prime-Power for High Energy Space Systems, Norfolk, Virginia, USA, Feb. 22-25, 1982. (Paper No. VI-2) Authors: Loferski, Joseph J.; (Division of Engineering, Brown University, Providence, RI 02912) Keywords: solar cells, Abstract: High efficiency solar cells are attractive for both space and terrestrial applications because they reduce the overall cost of a system
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