Lockheed Martin Microcryocoolers

Lockheed Martin's Advanced Technology Center, part of Lockheed Martin Space Systems Company, has developed a series of long life microcryocoolers for avionics and space sensor applications. We report the development and testing of three varieties of single-stage, compact, coaxial, pulse tube microcryocoolers. These coolers support emerging large, high operating temperature (100-150K) infrared focal plane array sensors with nominal cooling loads of 200-2000 mW, and all share long life technology attributes used in space cryocoolers, which typically provide 10 years of continuous operation on orbit without degradation. These three models of microcryocooler are the 345 gram Micro1-1, designed to provide 1 W cooling at 150 K, the 450 gram Micro1-2, designed to provide 2 W cooling at 105 K, and the 320 gram Micro1-3, designed to provide 300 mW cooling at 125 K while providing the capability to cool the IR focal plane to 125 K in less than 3 minutes. The Micro1-3 was also designed with a highly compact package that reduced the coldhead length to 55 mm, a length reduction of more than a factor of two compared with the other coldheads. This paper also describes recent design studies of 2-stage microcryocoolers capable of providing cooling at 25-100K. LMSSC is an industry leader in multiple-stage coolers, having successfully built and tested eight 2-stage coolers (typically cooling to 35-55K), and four coolers with 3 or 4 stages (for cooling to 4-10K). The 2-stage microcryocooler offers a very low mass and compact package capable of cooling HgCdTe focal planes, while providing simultaneous optics cooling at a higher temperature.