Radiation-Induced Power Degradation for GaAs/Ge Solar Arrays

This paper presents new radiation-induced power degradation data for GaAs/Ge solar arrays applicable to missions ranging from low earth orbit (LEO) to geosynchronous earth orbit (GEO) and compares these results to silicon arrays. These results are based on recently published radiation damage coefficients for GaAs/Ge cells. The power density ratio (GaAs/Ge to Si BSF/R) has been found to be as high as 1.83 for the proton-dominated worstcase altitude of 7408 km (MEO). Based on the EOL GaAs/Ge solar array power density results for MEO, missions which were previously considered infeasible may be reviewed based on these more favorable results. The additional life afforded by using GaAs/Ge cells is an important factor in system-level trade studies when selecting a solar cell technology for a mission and needs to be considered. The data presented in this paper is expected to support this decision since the selected orbits have characteristics similar to most orbits of interest.