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This paper describes a Stirling Cycle Refrigerator that has been built and tested by Stirling Technology Company (STC) for the NASA Marshall Space Flight Center (MSFC). Its intended application is the space station food refrigerator freezer. The Stirling Cycle Refrigerator described herein has few moving parts, is nontoxic to both humans and the environment, is insensitive to gravity, and has a moderate efficiency. Its temperature setpoint is adjustable, making it adaptable to other space station applications including a -70 °C freezer and freeze drier, a -183 °C freezer, and a -196 °C snap freezer. Test results have been very promising, with a Coefficient of Performance (COP) of 1.1 at -26 °C (-15 °F) and a heat load of 130 watts. Reliability tests on individual components and the entire Stirling Cycle Refrigerator system show a 10-year life is possible. In addition, the benefits of using this technology for the space station refrigerator freezer will be described.

Current and future microgravity studies in space based material science research call for rapid quenching of samples to permit microscopic examination of crystal structure, composition and growth dynamics. The conventional quench method, water spray, presents re-supply and consumables (weight, volume), safety, and recovery issues (water cannot be dumped on certain missions); therefore new techniques are sought. This work investigates a quench concept in which a gas quenchant is used in a small scale pin fin heat exchanger consisting of thermally conductive carbon fibers mounted on the sample cartridge and mounted normal to the surface. Analysis is presented for conditions including those relevant for microgravity crystal growth, where this type of heat exchanger is a viable candidate.