The Batch Manufacture of Stirling-Cycle Coolers for Space Applications Including Test, Qualification, and Integration Issues

Abstract

The Cryogenic Systems Group in Matra Marconi Space (UK) Ltd has been continuously involved in the development of Stirling Cycle coolers since 1986. The work started out under British Aerospace Space Systems Ltd which was acquired by MMS in 1994. A 50–80K Stirling cycle cooler has been developed with a heat lift capability of 1700 mW at 80K and 1100mW at 65K for a single compressor, single displacer unit. For most applications two coolers will be mounted in mechanical opposition for vibration cancellation purposes and therefore doubles the heat lift capability potential. This 50–80K cooler is a direct design derivative of the existing 80K cooler, formerly known as the BAe 80K cooler. The design changes incorporated were minimal and therefore achieves very strong linkage to the original Oxford 80K cooler for ISAMS. Fifteen of these coolers have been manufactured as a single batch quantity for various earth observation space instruments. The programme requirements are briefly presented, and the experience gained in manufacture and acceptance testing is discussed. During 1995 a cooler from this batch was allocated to a generic qualification test programme, including flight vibration, thermal vacuum and EMC testing before being put onto long term life testing. The data from this test programme is presented, including an update of the life test.

All of these coolers with the exception of the qualification cooler were supplied into instrument flight programmes. The experience gained and issues arising from the requirement for MMS to integrate some of these coolers into flight bracket systems is discussed. These issues include factors such as end load limitations on the displacer cold finger.