Flight Results from the Cryogenic Capillary Pumped Loop (CCPL) Flight Experiment on STS-95

This paper describes the Cryogenic Capillary Pumped Loop (CCPL) flight experiment, which flew as part of the CRYOTSU payload on STS-95 in late 1998. The CCPL flight unit is a miniaturized two-phase fluid circulator for transporting cooling power from cryogenic cooling sources (cryocoolers) to remote cryogenic components. During the 9-day flight, the N₂-charged CCPL operated successfully over six test cycles (~70 hours). Heat loads were varied from 0-3 W and tests included several startups, power cycles, cold reservoir set-point tests, and condenser sink temperature tests. Ground and flight test data is included herein. The zero-g environment had no discernible impact on CCPL operation.