Pulse Tube Microcooler for Space Applications

This paper describes a new small, low mass, pulse tube cryocooler designed for space flight cooling. The compressor is a scaled down version of Northrop Grumman Space Technology's (NGST) existing line of flight qualified compressors with a mass of less than 500 grams. Because it is scaled from NGST's larger space compressors it has all their characteristics which result in very high reliability and low vibration. This includes the use of Oxford flexure springs and vibrationally balanced back to back compressor modules driven by voice coil motors. The cooler uses a split configuration with a remote coaxial cold head, although it can be readily reconfigured for an integral cold head. The coaxial pulse tube cold head was optimized to utilize the small swept volume of this compressor. At 298 K reject, this cooler can lift 1.1 W at 77 K. This paper describes this cooler, its components and interfaces and presents test data over a range of input powers and reject temperatures.