CubeSat Si Solar Cells Long-Term Degradation in Open-Space Conditions

This study evaluates the enduring performance of silicon solar cells aboard the 2014-launched CubeSat, PolyITAN-1. Despite lower efficiency, cost-effectiveness and reliability were prioritized for the satellite's energy requirements. Ground tests indicated a 24 % efficiency and 7W capacity. In space, telemetry data revealed individual solar panel capacities of 1-1.5W, totaling 8-9W. High radiation levels in the inner Van Allen Belt caused cell degradation, aligning with modeling predictions of up to 70 % reduction in the first two years, stabilizing at 20–30 % thereafter. Contrary to predictions, some cells exhibited less than 10% degradation during first years, credited to advanced technology incorporating a back-surface field and reflector structure and high-carrier-lifetime silicon wafers. The PolyITAN-1 mission showcases CubeSats as cost-effective space access for education and research, with the chosen solar cells demonstrating remarkable resilience to open-space challenges.