The Dynamic Interplay Between Spacecraft Charging, Space Environment Interactions and Evolving Materials

The charge on spacecraft is constantly changing, as a result of the dynamic nature of the space environment, the spacecraft orbit, the interactions between environment and spacecraft, and even the spacecraft materials. While the effects on spacecraft charging from varying environmental conditions and from the selection of different construction materials have been studied extensively, the modification of material properties by the space plasma environment can also have profound effects on spacecraft charging. These same considerations apply to other extreme plasma applications. This presentation focuses on the measurement methods and modeling we use to study electron emission and transport processes, charging, luminescence, and arcing of conducting and insulating materials under electron, ion and photon bombardment. Particular emphasis is placed on measurements of extremely good insulators, where internal charging significantly affects the measurement processes. These results are used to assess the effects of environment-induced material modifications (e.g., roughening, contamination, oxidation, aging, defect generation) on the physical properties used as input parameters for charging simulations