Prototype Spacecraft Cryocooler Progress

Abstract

The Phillips Lab/Hughes Protoflight Spacecraft Cryocooler (PSC) is a space qualified, low vibration, single stage Stirling refrigerator that provides over 3.0 W refrigeration at 60 K and over 1.25 W at 35 K. All program performance requirements have been met or exceeded and data are presented in this paper. The cooler design is derived from the Phillips Lab/Hughes 65K Standard Spacecraft Cryocooler (SSC), with significant improvements in the areas of residual vibration, weight, efficiency, mechanical robustness, and user interfaces. One unit has been built and tested. The compressor module uses a three finger tangential flexure suspension system, resulting in significant vibration reductions. The expander module retains the low vibration spiral flexure design utilized in the SSC. PSC mass has been reduced to 13 kg from the 19 kg mass of the SSC. Specific power referenced to the motor inputs for the 2 W/60 K operating point at 300 K rejection temperature has improved from 35 WAV (SSC) to less than 30 WAV (PSC). User interfaces have been improved by the addition of aluminum heat rejection flanges on the compressor and expander modules, which simplifies the end users heat rejection hardware and installation procedures. A method to project cooler performance when integrated with a user’s system specific thermal interfaces is also provided.