Thin-film photovoltaic radiation testing and modeling for a MEO orbit

A radiation test plan for thin-film photovoltaic technologies focused on a MEO flight experiment is outlined. The radiation response of thin film, triple junction amorphous Si solar cells, with and without a space coating, is presented. The degradation of the photovoltaic output under 2 MeV proton irradiation is measured and analyzed. Irradiations performed both at room temperature, in the dark, and at open circuit and at elevated temperature, under illumination, and under load were performed. The experimental data are presented and analyzed. These data will form the basis for an on-orbit prediction model as applied to a high-radiation MEO orbit.