Development of a Two-Stage Pulse Tube Cryocooler for 35 K Cooling

Abstract

Lockheed Martin has developed a unique two-stage, linear motor driven pulse tube cryocooler for cooling at 35 K for space applications. This system, developed under Lockheed Martin Independent Research and Development (IRAD) funding, demonstrates excellent power efficiency, providing 0.5 W of heat lift with 57 W of compressor power. A no-load temperature of 19.8 Kwas achieved.

Performance data were obtained at both the design point, 35 K with no cooling at the warm stage, and also with cooling at both stages over a range of temperatures. At the design point (0.5 W at 35 K), the cooler surpassed the original programmatic requirements. The coldhead configuration is readily adaptable to meet specific temperature and load requirements, which is advantageous in that a cryocooler can be optimized for specific applications without the extensive development effort required for compressors. Based on the performance of this cooler, the rapid development time, and high reliability, resized versions of this configuration have been selected for two contracts currently underway for space applications.

Other dual stage systems developed at LM-ATC and their relative merits are discussed.