In-Flight Aging of Thermal Coatings: THERME Experiment

摘要

Centre National d’Etudes Spatiales has developed a simple and low-cost experiment called THERME to evaluatenthe in-flight degradation of common space coatings, in which temperature measurements are taken to monitor thenevolution of solar absorptivity. The experiment payload is now carried on low-Earth-orbit satellites such as SPOT 5,nHELIOS 2A, and DEMETER. In-orbit results provided for some thermal control coatings (white paint, secondnsurface mirror, and Kapton) show the effects of the low-Earth-orbit space environment. Nevertheless, sometimesncoatings are more degraded in flight than in ground simulation tests. A possible explanation is that the coatings arencontaminated by organic products outgassed when the satellites are placed in orbit. The degradation of the coatingnwould then be due to this early contamination combined with solar radiation, while the flux of atomic oxygen hittingnthe coating could reduce the degradation by eroding the contamination layer. This hypothesis is consistent with thenspace environment, the temperature, and the coating chemistry.