Post-flight analysis of materials exposed on the spectrometer sub-unit of MEDET (18 months on-board ISS)

Abstract

A variety of materials were exposed to the Low Earth Orbit (LEO) environment, mainly Ultraviolet Radiation and Atomic Oxygen, through The Material Exposure and Degradation Experiment (MEDET). The degradations of polymeric films with and without atomic oxygen protection coating, quartz with and without thermal control coating, and solar cell cover glass adhesives, were studied in flight and post-flight. Yellowing for AO protected polymeric films and silicone resins due to UV exposure and the decrease of thicknesses for other samples like polymeric films due to AO erosion have been highlighted. Thermo-optical properties have been determined and the surface morphology classified as cone-like due to surface erosion or containing microcracks in silicone layers.