The Aerospace Corporation has independently developed conceptual designs for microsatellites and nanosatellites. This development of microsatellites and nanosatellites for low earth orbits requires the collection of sufficient power for onboard instruments with a low weight, low volume spacecraft. Because the overall surface area of a microsatellite or nanosatellite is small, body-mounted solar cells are incapable of providing enough power. Deployment of traditional, rigid, solar arrays necessitates larger satellite volumes and weights, and also requires extra apparatus needed for pointing. One potential solution to this "power choke" problem is the deployment of a large, spherical, inflatable power system. This power system, termed the "PowerSphere", would offer a high collection area, low weight, and low stowage volume, and eliminate the need for a pointing mechanism.(1,2) Development of the Powersphere concept over the last year focused on the design and fabrication of Amorphous Silicon Solar Cells that would meet the space environmental requirements. This is a cooperative effort between The Aerospace Corporation and Iowa Thin Film Technologies, Inc. Modifications to the terrestrial product line necessary to produce a thin film Amorphous Silicon Solar Cell suitable for space applications have been identified.(3) A number of experiments have been performed in The Aerospace Corporation's Laboratories to develop a more robust top contact to collect cell current for the otherwise terrestrial cell produced by Iowa Thin Film Technologies production line. The up-to-date results of this effort are presented in this paper. The Aerospace Corporation has a cooperative effort with SRS Technologies to develop an appropriate transparent thin film "Cover Glass" for the Amorphous Silicon Solar Cell fabricated by Iowa Thin Film Technologies. The thin film "Cover Glass" is needed to increase the thermal emissivity of the solar cell.(4) Without the emissivity-raising "Cover Glass", the cell operating temperature would be excessive.
