Thermal and exported vibration characterization of RICOR K508N cryocooler

Abstract

Abstract The RICOR K508N is an upgraded version of the K508 that has extensive flight heritage. This paper reports on the thermal performance and exported force results for a COTS K508N for the ATACOI project as well as two K508N coolers filled to a higher fill pressure and with a high frequency motor for the CIRAS mission. The thermal performance of the coolers was measured in vacuum for -40°C, 20°C and 57°C heat reject temperatures. The coolers were operated in open-loop and in closed-loop mode during thermal performance testing. The K508N for ATACOI was put through Protoflight/Qualification thermal vacuum testing in order to satisfy JPL environment requirements for flight. Exported vibration results for the ATACOI, CIRAS and MASPEX coolers are presented and compared. Finally, the ATACOI K508N was tested with and without wire rope vibration isolators to validate the results presented in Ref. [11]. As a result of increased fill pressure and a high frequency motor, the CIRAS coolers showed a 22% performance improvement at 90 K compared to the ATACOI cooler.