Cryogenic heat pipes in spacecraft applications

Presented here is a review of the recent research and developmental work that has been done in the area of cryogenic heat pipe design, analysis, and testing. Included is a discussion of the working fluids, wicking structures, and testing procedures currently used in cryogenic heat pipes. Problem areas such as priming difficulties, testing complexity, extrapolation of one-g ground test results to zero-g applications, and heat pipe startup from the supercritical state are discussed. Other problems associated with construction materials, wick structures, and working fluids are also presented and discussed.