Abstract
Spacecraft structures in low earth orbit (LEO) encounter a degradation problem caused by atomic oxygen in the space environment. This study presents an experiment of impact degradation on the ground. The experiment was carried out in a vacuum space chamber. Atomic oxygen produced at a plasma torch was accelerated fluid dynamically with Argon working gas. As the target materials several carbon-based materials (graphite, C/C composite and Si-C.C.) were employed. The degradation was analyzed in the aspect of macroscopic mass loss per unit area and the microscopic degradation modes'. The temperature effect is investigated. The comparison among the target materials is developed. The mass loss per unit area depends on the temperature of material surface. The eroded surfaces of materials were observed with SEM. In case of C/C composite, the matrix region erodes more than carbon fiber, however, this effect is more pronounced in normal oxidation at ambient atmosphere. The mass loss of Si-C.C. is less than that of corresponding C/C composite and only the C/C composite region erodes deeply with almost no erosion in Si and SiC regions.
