UNITED STATES AND RUSSIAN THERMAL CONTROL COATING RESULTS IN LOW EARTH ORBIT

Both the United States and Russia have conducted a variety of space environment effects on materials flight experiments in recent years. Prime examples are the long duration exposure facility, which spent 5 years and 9 months in low Earth orbit from April 1984 to January 1990, and the removable cassette container experiment, which was flown on the Mir orbital station from Jan. 11, 1990 to April 26, 1991. Thermal control coating materials data generated by these two missions are evaluated by comparing environmental exposure conditions, functionality and chemistry of thermal control coating materials, and preand postflight analysis of absorptance, emittance, and mass loss due to atomic oxygen erosion. These are noticeable differences in the United States and Russian space environment measurements and models, which complicates comparisons of environments. Nevertheless, the results of both flight experiments confirm that zinc oxide and zinc oxide orthotitanate white thermal control paints in metasilicate binders are the most stable upon exposure to this space environment. Russian flight materials experience broadens to the use of silicone and acrylic resin binders whereas the United States relies more heavily on polyurethane.