Effects of Secondary Electron Emission Yield of Polyimide Films on Atomic Oxygen Irradiation

Abstract

Secondary electron emission (SEE) from metal and insulating materials used for satellite thermal insulation or other such purposes was studied. The SEE yield measurement is very important for analyzing charge accumulation on satellite surfaces in a space environment because electron emission related to irradiated electrons influences the amount of surface charge. We considered degradation phenomena of spacecraft materials’ surface caused by irradiation with atomic oxygen from two different sources. The SEE yields might change for a non-degraded sample. We measured the SEE yields for spacecraft material surfaces that were exposed to space environment factors. In preparation of exposed to space factors samples, they were irradiated by atomic oxygen (AO) to simulate degradation in a space environment. The samples were exposed to two different AO sources and three different fluencies, corresponding to different conditions of GEO orbit and time on orbit. This report is discussing the results for the polyimide films and the relationship between the SEE yields and sample degradation when irradiated by atomic oxygen. Furthermore, we consider the effect of different AO irradiation methods: the laser detonation method and the plasma asher method.