On the Possibility of Optical Degradation of Solar Batteries of Space Vehicles under the Influence of Low-Energy Protons

A physical mechanism that can explain the anomalous optical degradation of solar panels on spacecraft operating in medium-high circular orbits is considered. This mechanism is based on the selective removal of oxygen atoms from oxides under proton irradiation. This exposure results in the formation of a thin, altered SiO layer on the surface of the protective glass of the photoconverters, which has a high optical density within the spectral sensitivity range of the photoconverters. Estimates show that with complete oxygen release, optical losses in silicon photoconverters reach 7% and in three-cascade GaAs-based photoconverters, 17%. The minimum proton fluence required for this is 2.2 × 10 1/cm. This can be achieved by protons from the plasmasphere bombarding the charged surface of the spacecraft.