Earth Observing-1 Technology Validation: Low Absorptance Inorganic White Paint AZW/LA-II

The Earth Observing-1 (EO-1) spacecraft, built by Swales Aerospace for NASA’s Goddard Space Flight Center (GSFC), was successfully launched on a Boeing Delta-II ELV on November 21, 2000. The EO-1 spacecraft thermal design is a cold bias design using passive radiators, regulated conductive paths, thermal coatings, louvers, thermostatically controlled heaters and multi-layer insulating (MLI) blankets. Several technology demonstrations were flown on EO-1. A late arrival to EO-1 was a technology demonstration to verify the thermal performance of a possible improved white thermal control coating developed by AZ Technology, Inc. The thermal control coating referred to as AZW/LA-II, is a low absorptance inorganic white paint. A low absorptance thermal coating allows radiators to run cooler when exposed to UV environments providing improved performance for space radiators. Two flight calorimeters, built by Swales Aerospace, were flown on the Earth Observing-1 spacecraft. Using the known NASA/GSFC Z93P White Paint as a baseline for comparison, the data provided from the calorimeters was used to validate the performance of the LA-II low alpha inorganic white paint. The paper will present the current on-orbit status of the AZW/LA-II white paint, the on-orbit flight data, thermal model correlation results, lessons learned, and the current and future uses of the AZW/LA-II thermal control coating.