Assessment of AP9 and solar cell degradation models with flight data

The estimation of space radiation effects on solar cells comprises two main elements, a space radiation model and a solar cell degradation model. The widely used AP8 trapped proton model has recently been updated with the creation of the AP9 statistical model. Independently an alternative to the standard JPL equivalent fluence model for cell degradation has been developed over the last decade. The displacement damage dose model has the advantage over the JPL method of requiring far less empirical data on cell performance. In this paper the predictions of these two space proton environment models and two cell degradation models are compared with flight data on GaAs and Si single junction solar cells from the ASCOT flight experiment. It is shown that no single combination of environment and cell model has the best agreement with all of the flight data, suggesting that additional refinements in both are needed.