Design properties for state-of-the-art thermal control materials for manned space vehicles in LEO

Abstract

Literature reports on spacecraft thermal control coatings generally emphasize changes in nominal properties after exposure to one or more of the space environments. Few have addressed the coating variability caused by normal processing tolerances and the variability at the end-of-life after environmental exposure in orbit. For critical thermal designs, this information is required by the thermal designer. The purpose of this paper was to collect design information used for conducting thermal analyses for the thermal control coatings used by Product Group 1 of the International Space Station Alpha. Both nominal values and manufacturing tolerances are listed for the beginning-of-life and for the end-of-life of the coating. In assessing the end-of-life values, McDonnell Douglas Aerospace (MDA) took into account contaminant deposition on the coatings and the influence of the natural environments on the deposited contamination layer. Because of the eroding effects of atomic oxygen on organic materials, most coatings selected were inorganic, including Z-93, conversion coatings, anodic coatings, and metal tubing with and without plating. Silicone-based paints and silverized Teflon were used for a few specific applications. This paper provides design information and tables for each of the coating categories defined and can serve as a convenient design reference for the thermal designer.