Improved Standard Spacecraft Cryocooler Life Test for Space-Based Infrared Surveillance
Two Hughes Improved Standard Spacecraft Cryocoolers (ISSCs) are currently in life test to support the cooling needs of space-based infrared surveillance sensors. These coolers are improved versions of the Hughes/Air Force/Phillips Laboratory developed 65K Standard Spacecraft Cryocooler. The ISSC is a split-Stirling cryocooler designed for 1.25 W of cooling at 60K. The ISSC coolers under test carry cold end loads of 600 mW at 60K and 832 mW at 60K, respectively. They are mounted in separate vacuum chambers. Their heat rejection temperatures alternate between 280K and 290K once per month to simulate on-orbit temperature extremes.
The first test started in May 1993 and has accumulated 10 months of operating time as of April 1994. It is currently operating within its required performance envelope of 600 mW at 60K for less than 60 W of total motor power. The second test started in June 1993 and has accumulated 9 months of operating time as of April 1994. It is currently operating within its required performance envelope of 832 mW at 60K for less than 60 W of total motor power.
The ISSC is attractive for near term surveillance applications because of its high cooling capacity at 60K. Although this cooler has not served on-orbit to date, a spaceflight experiment is planned for February 1995 as part of NASA’s In-Space Technology Program Cryo System Experiment.
KeywordsInput Power Thermal Load Motor Power Life Test Vibration Exposure
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- 1.R.S. Sugimura and S.C. Russo, “Lessons Learned During the Integration Phase of the NASA IN-STEP Cryo System Experiment,” presented at the 8th International Cryocooler Conference, Vail, Colorado (1994).Google Scholar