High efficiency solar cell arrays system trade-offs

Advanced high efficiency GaAs/Ge solar cells are now being manufactured in large quantities and are being utilized on many spacecraft. Since the bare solar cell cost and efficiency is much higher than silicon cells, it is often difficult to determine the system cost advantages that are hard to quantify in terms of cost benefits. In order to provide some guidance in this cell comparison, a systems trade study was performed and cost comparison charts prepared. We are now at a stage where the system advantages of high efficiency solar cells and arrays are being recognized. Many spacecraft missions have now incorporated GaAs/Ge solar cells in their designs because there are specific benefits that are achieved. At the array level, costs may be 50% higher, however, at the system level the costs of GaAs/Ge solar cell arrays can be shown to be 60 to 80% of the cost of a comparable silicon solar cell array design.