The Flight Model Stirling Cryocooler System for the INTEGRAL Spectrometer

The Astrium Stirling cycle cryocooler system is to provide cooling for the spectrometer on the International Gamma Ray Astrophysics Laboratory (INTEGRAL), an ESA space science satellite. This system has been designed, manufactured, assembled and tested by ASTRIUM Ltd. under direct ESA contract. It is comprised of four standard 50–80 K Stirling cryocoolers, arranged in redundant pairs and configured for vibration minimisation. Two spare cryocoolers have also been fully validated. Heritage has been maximised by using mechanisms with existing flight heritage and previously qualified flexible thermal link assemblies. Performance characterisation of the flight cryocoolers has been completed, including verification of cooling capability, passive vibration control, synchronisation of the two pairs and the effectiveness of the active launch-lock control of compressor and displacer pistons.