Long-life spaceborne cryocooler for the Advanced Spaceborne Thermal Emission and Reflection Radiometer/Short Wavelength Infrared Radiometer (ASTER/SWIR)

A long life spaceborne Stirling cycle cryocooler named 'LS-5A' has been developed for use to cool the detector mounted on the Short Wavelength Infrared Radiometer (SWIR) of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The cryocooler is applied Stirling cycle, supplies 1.2 watt cooling at the cooling temperature of 70 K, and consist of a twin-opposed piston compressor unit and a expander unit balanced by an active balancer to minimize the self-induced vibration. In order to accomplish 5 years of continuous operation in orbit, the cryocooler has noncontact clearance seals for pistons supported by suspension springs to avoid the wear of seal materials. Cooling performances and self-induced vibration levels were evaluated, and a life test cryocooler has been running for 7300 hours without any performance degradation.