Cold Survival Thermal Solutions for Landsat-7 ETM+ Instrument in Sun-Pointing Safehold Cold Case

The original thermal design of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) scanner was inherited from Landsat-4, 5 and 6 at the instrument Critical Design Review (CDR). The ETM+ Auxiliary Electronics Module (AEM) and Full Aperture Calibrator (FAC) are new components and had no heritage thermal design at the CDR. More than a year after the CDR, the Landsat-7 program was transferred from the U.S. Air Force to the National Aeronautics and Space Administration (NASA). NASA added the sun-pointing safehold mode which has significant thermal impacts on the instrument. The temperature predictions for the scanner were much colder than the survival temperature limits in the sun-pointing safehold cold case. This paper presents thermal solutions to the cold survival problems. The solutions have no major impacts on the program cost and schedule.