Results of Space-Environment Exposure of the Flexible Optical Solar Reflector

摘要

This paper presents exposure results for the flexible optical solar reflector, a sample material in the International Space Station Service Module/Micro-Particles Capturer and Space Environment Exposure Device experiment mission. The flexible optical solar reflector, which has a conductive layer and a mirror layer coated on a polyetherimide base film, is a thermal control film material for spacecraft. It achieves low solar absorptance and high infrared emittance. Results indicate a mass increase: the flexible optical solar reflector was not eroded by atomic oxygen in low Earth orbit. Thermo-optical properties show no significant change. In fact, flexible optical solar reflector is confirmed to retain its initial properties after exposure on an International Space Station orbit for 46 months. Transmission electron microscopy observation of the cross sections including the exposed surface showed that a new layer had formed over the flight sample. Qualitative analysis of the new layer indicates that the layer mainly comprises silicon and oxygen. The layer is chemically produced by deposited silicone contamination and atomic oxygen, which would be SiO_2. This experiment also provides actual quantitative contamination data on the International Space Station, contributing to improvement of contamination control on the International Space Station in the future.