Development of a valved linear compressor for a satellite borne J-T cryocooler

The provision of temperatures below 12 K is essential for sub-mm and FIR observations from satellite instruments. Historically this has been achieved with stored cryogens, however mechanical coolers could potentially provide higher reliability and flexibility. These cryocoolers typically incorporate a regenerative cold-finger, such as a pulse-tube, however this can be replaced by a recuperative Joule-Thompson stage to obtain the lowest temperatures required. The major change to the compressor is the requirement for steady flow. This paper describes the development of such a compressor using reed valves, based on space-qualified hardware. Long life potential was demonstrated by measuring the motion of the valves during operation. A model was also developed and validated to optimize performance.