The Development, Verification, and Application of a Spacecraft Cryogenic Phase Change Thermal Storage Unit

This paper presents a summary of the design, development, and ground verification of the BETSU (Brilliant Eyes Thermal Storage Unit) experiment. The BETSU utilizes 2-methyl pentane as a 120 K PCM (Phase Change Material) and will be flown on board the Shuttle in early 1994. There has been very limited experience with the space flight of cryogenic phase change materials.

Space applications for a cryogenic TSU include the storage of energy for the cooling of temperature sensitive sensor components such as focal planes, optics, mirrors, and telescopes. Based on ground test data, trade studies were performed which show the significant weight and cost benefits of the BETSU technology.