Miniature space pulse tube cryocoolers

Abstract Cryogenic coolers for use in space on small satellites require low power and minimum weight. The need for exceptional reliability in a space cooler is made even more critical on small satellites since cooler redundancy is often not an option due to weight and power constraints. In this paper we report on our space qualified pulse tube cooler designed specifically for use on small satellites. The miniature pulse tube cooler is intended for greater than 10 year long-life space application and incorporates a non-wearing flexure bearing compressor vibrationally balanced by a motor-controlled balancer and a completely passive pulse tube cold head. The efficient cooler control electronics incorporate temperature and vibration control systems as well as extensive telemetry and engineering diagnostics. Cooler systems incorporating the mechanical cooler and associated drive electronics have been flight qualified and launched in 1997 as focal plane coolers. Four additional flight coolers have recently been delivered for use in cooling optics in an infrared telescope system. In this paper we report the performance and flight qualification of these mechanical coolers and flight electronics.