Spacecraft materials on orbit are subjected to the harsh weather of space. In particular, high-energy electrons alter the chemical structure of polymers and cause charge accumulation. Understanding the mechanisms of damage and charge dissipation is critical to spacecraft construction and operational anomaly resolution. Energetic particles in space plasma break molecular bonds in polymers and create radicals that can act as space charge traps. These electron-induced chemical changes also result in changes to the spectral absorption profile of polymers on orbit. Radicals react over time, either recreating identical bonds to those in the pristine material, leading to material recovery, or creating new bonds, resulting in a new material with new physical properties. Lack of knowledge about this dynamic aging is a major impediment to accurate modeling of spacecraft behavior over its mission life. This chapter first presents an investigation of the chemical and physical properties of polyimide films (PI, Kapton-H®) during and after irradiation with high-energy (90 keV) electrons. Second, the deleterious effects of space plasma on a spacecraft component level are presented. The results of this physical/chemical collaboration demonstrate the correlation of chemical changes in PI with the dynamic nature of spacecraft material aging.
Part of the book: Plasma Science and Technology