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.