Design and manufacturing experience with GaAs/Ge solar cells as gained with the TEMPO solar generator program

Besides a few relatively small applications, to date practically all spacecraft have been alimented by solar arrays based on silicon solar cells. Different types of cells have been developed resulting in different characteristics and cost. The relation is, however relatively proportional. The TEMPO digital communication satellite is the first to use GaAs/Ge solar cells in large quantities. For three identical arrays, around 80,000 cells have been applied so far; further rebuilds have also been started. In the following paper, the main relevant application differences of GaAs/Ge solar cells are compared with standard and advanced Si solar cells as currently used in the space power field