ABSTRACT
At COMSAT Laboratories in 1967, the Spacecraft Laboratory studied all non communications aspects of the communications satellites; that is, everything related to the satellite itself including structure, thermal attitude, power, etc. In my case, I was responsible for primary power development in the Electric Power Department of the Spacecraft Laboratory In 1967, all satellites were powered by silicon solar cells. We examined every major type of solar cell that was available in manufacture or under development including, silicon, cadmium sulfide, and cadmium telluride cells. We rapidly concluded that only silicon solar cells were a viable option at that time since the other devices were neither stable enough nor had good radiation properties. We thereupon characterized every silicon solar cell under manufacture that we could purchase doing all a full battery of tests to determine how well they would perform in a space environment. We also tested every type of transparent or translucent solar cell shielding material available that could be used to protect the solar cells from radiation in space including fused silica, Microsheet, Kapton and other plastics and even spray on coatings. At that time, the best material was fused silica. Finally, we also tested the various adhesives that were used to bond the shielding materials to the cells, both for stability and performance under radiation. From this data we predicted what solar cells, adhesives and shielding materials performed the best under space conditions. Finally, taking all of the data and recommendations we made predictions of how solar cell arrays of silicon solar cells with various shielding materials would perform in space over time.
