AES and SEM/EDS Analysis of Silvered Teflon Laminates of Optical Solar Reflector

Abstract

<jats:p>The Optical Solar Reflector (OSR) of Earth Observing System-PM (EOS-PM) is made of a flexible function layer of silvered Teflon/Inconel/Kapton laminate bonded to a honeycomb panel. After having been thermal cycled in vacuum, the laminate/panel was irradiated in air with UV at 2.2 equivalent suns intensity for 500 hours. Severe darkening was observed in areas exposed to UV but little or no darkening occurred in adjacent but shaded areas. Drastic increase of absorptance was observed-due to the darkening.</jats:p><jats:p>In order to investigate the cause of the degradation, test samples were irradiated at different configurations for 1000 equivalent sun hours (ESH). These samples were freestanding laminates and irradiated in vacuum and air, respectively. No darkening was observed on the sample that was irradiated in vacuum. Severe darkening was observed on the sample that was irradiated in the air. A laminate sample was irradiated in dry nitrogen for 1000 ESR and found no darkening either.</jats:p>