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Peter Shirron (a), Ed Canavan (a), Michael DiPirro (a), John Francis (a), Michael Jackson (a), James Tuttle (a), Todd King (a), and Matt Grabowski (b)
(a) NASA/GSFC
Cryogenics and Fluids Branch
Code 552
NASA/ Goddard Space Flight Center
Greenbelt MD 20771
b SSAI
Constellation-X is a multi-satellite X-ray astronomy mission presently being planned for launch in the 2010 time frame. Each of four identical satellites will contain a telescope and instruments for imaging and spectroscopic analysis of hard and soft X-rays. The X-ray Microcalorimeter Spectrometer (XMS) instrument will use arrays of microcalorimeters to detect X-rays with energies from 0.2 to 6 keV. To achieve the desired energy resolution of 2 eV, the detectors will be cooled to 50 mK. The projected cooling power requirement is approximately 5 microW. In order to meet the mission lifetime requirement of 6 years (with a goal of 10 years), a mechanical cryocooler will be used to provide a heat sink for the low temperature cooler. In this paper we discuss the development of a continuous adiabatic demagnetization refrigerator (CADR) that meets the cooling requirements of the XMS instrument. The four-stage CADR presently being tested can operate continuously at 50 mK using a 4.2 K helium bath as a heat sink. Its cooling power of 6 microW at 50 mK exceeds the XMS requirement, and its peak heat rejection rate is less than 7 mW. Details of the CADR's design and operation, as well as the development program leading up to a flight-qualified instrument, are discussed.
Pages 581-588
Cryogenics, Volume 44, Issues 6-8 (June - August 2004)
[2003 Space Cryogenics Workshop,
Edited by M. Larson and W. A. Holmes]