Final Flight Data Report from ASCOT

This paper presents selected results from five years of flight data obtained by the Advanced Solar Cell Orbital Test (ASCOT). The experiment contains five types of advanced cells, including GaAs/Ge single junction devices from both Tecstar and Spectrolab, and two types of silicon cells as reference devices. The total equivalent 1 MeV electron fluence received by the silicon cells exceeds 1.2E16/cm² , giving this experiment the highest cumulative radiation exposure of any to date. Complete IV curves were obtained for the entire period, and these have been compared with models of predicted degradation. The degradation of the silicon reference devices suggests a highly dynamic trapped proton environment, not well represented by the standard AP8 model, that is confirmed by dosimeters flown concurrently on spacecraft in similar orbits. Evidence of annealing in the GaAs devices is apparent during naturally occurring periods of low proton flux