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Ball Aerospace has completed qualification testing of its flight Stirling-cycle mechanical cryocooler for the Thermal Infrared Sensor (TIRS), an instrument slated to fly on the Landsat Data Continuity Mission (LDCM) platform. The TIRS cooler, developed under subcontract to NASA Goddard Space Flight Center, consists of a sophisticated and highly reliable, two-stage, fixed regenerator Stirling cryocooler and its drive electronics. The TIRS cooler provides 2 W of 38 K cooling to the TIRS detectors and 9.8 W shield cooling to 85 K for less than 225 W total input power. Performance test results are reported. [ABSTRACT FROM AUTHOR]

NASA's vision for Space Exploration that would return humans to the Moon by 2020 in preparation for human explorations of Mars. This requires innovative technical advances. The lunar mission requires a temperature-lift (heat pump) technology to reject waste heat to hot lunar surface (heat sink) environments during lunar daytime. The lunar outpost and Lunar Surface Access Module (LSAM) to operate anywhere during the hot lunar daytime require a high performance and energy-efficient, yet reliable refrigeration technology. A vapor compressor-driven hybrid two-phase loop was developed for such high temperature-lift applications. The vapor compression loop used an advanced porous wick evaporator capable of gravity-insensitive capillary phase separation and excess liquid management to achieve high temperature-lift, large-area, isothermal and high heat flux cooling capability and efficient compression. The high temperature lift will allow the lunar surface systems use compact radiators by increased heat rejection temperature. [ABSTRACT FROM AUTHOR]

In March 2002, a single-stage turbo-Brayton cryocooler was installed on the Hubble Space Telescope (HST) to re-establish cooling to the detectors in the Near Infrared Camera and Multi-Object Spectrograph (NICMOS). The system has maintained the detectors at their operating temperature near 77 K since that time. Future NASA space missions require comparable low-vibration cooling for periods of five to ten years in the 6 K–10 K temperature range. Creare is extending the NICMOS cryocooler technology to meet these lower temperatures. The primary activities address the need for smaller turbomachines. Two helium compressors for a 6 K turbo-Brayton cycle have been developed and tested in a cryogenic test facility. They have met performance goals at design speeds of about 9,500 rev/s. A miniature, dual-temperature high specific speed turboalternator has been installed in this test facility and has been used to obtain extended operational life data during low temperature cryogenic tests. A smaller, low specific speed turboalternator using advanced gas bearings is under development to replace the original dual-temperature design. This machine should provide improvements in the thermodynamic performance of the cycle. This paper presents life test results for the low temperature system and discusses the development of the smaller turboalternator. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Since the large coils in a cryocooled HTS utility transformer can be located more than a meter away from the cryocooler cold heads, conductive cooling would require very large, heavy thermal links to keep temperature differentials small. Under a U.S. Department of Energy (USDOE) Superconductivity Partnership with Industry (SPI) agreement with Waukesha Electric Systems (WES), SuperPower Inc. (SP), Energy East (EE), and Oak Ridge National Laboratory (ORNL), we have developed a closed-loop helium system that couples the coils to the cold heads using natural convection cooling. The loop operates on a single-phase thermosiphon principle at temperatures and pressures from 20 to 45 K and 10 to 20 bars, and needs no external compressor to maintain helium gas circulation. Design procedures for the heat exchangers on both the cold heads and coils and for the interconnecting piping will be summarized. A 30-W cooling loop was successfully operated on a 1-MVA prototype transformer. A 350-W system for a 5/10-MVA prototype transformer has been built and tested with a dummy load over a wide range of heat loads corresponding to the range from normal transformer operation to two times (2×) overload. Later, this system successfully cooled down the 4.5-ton cold mass of the transformer to temperatures below 30 K. Design details of the hardware and performance of the assembled systems will be summarized. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]