Development of Microcryocoolers for Space and Avionics Applications

Lockheed Martin’s Advanced Technology Center has developed a series of Microcryocoolers for a range of applications including avionics and space sensors and instruments. We report the development and initial testing of the recently developed first-article, single-stage, compact, coaxial, Fast Cooldown Pulse Tube Microcryocooler (FC-PTM). The new cryocooler supports cooling requirements for emerging large, high operating temperature (105-150K) infrared focal plane array sensors with nominal cooling loads of ~300 mW at105K at 293K ambient. This is a sequel development that builds on our inline and coaxial pulse tube Microcryocoolers reported at CEC 2013 7 , ICC 18 8,9 , and CEC 2015. 10 The new FCPTM and the prior units all share our long life space technology attributes, which typically have 10 year life requirements. 1 The new prototype Microcryocooler builds on the previous development by incorporating cold head design improvements in two key areas: 1) reduced cool-down time, and 2) novel repackaging that greatly reduces envelope. The new coldhead and dewar were significantly redesigned from the earlier versions in order to achieve a cooldown time of 2-3 minutes— a projected requirement for tactical applications. A design approach was devised to reduce the cold head length from 115mm to 55mm, while at the same time reducing cooldown time. We present new FC-PTM performance test measurements with comparisons to our previous pulse-tube Microcryocooler measurements and design predictions. The FC-PTM exhibits attractive small size, volume, weight, power and cost (SWaP-C) features with sufficient cooling capacity over required ambient conditions that apply to an increasing variety of space and tactical applications. This paper presents performance characteristics and qualification status of the various Microcryocoolers.