Terrestrial solar cells in space [radiation tolerance]

Mission Demonstration-test Satellite No.1 (MDS-1), successfully completed its mission operation in September 2003 with a lot of precious data on the radiation tolerance of six kinds of solar cells developed for terrestrial use. CIGS cells demonstrated superior radiation tolerance, while polycrystalline silicon cells exhibited abrupt degradation due to the very severe radiation environment in geostationary transfer orbit. We report the flight data of the terrestrial solar cells during the mission operation. End-of-life prediction methodologies developed by JPL and NRL are applied to the flight data, based on ground irradiation tests.