The XRS low temperature cryogenic system: Ground performance tests results

Abstract The X-Ray Spectrometer (XRS) instrument is part of the Astro-E mission scheduled to launch early in 2000. Its cryogenic system is required to cool a 32-element array of X-ray microcalorimeters to 60–65 mK over a mission lifetime of at least 2 years. This is accomplished using an adiabatic demagnetization refrigerator (ADR) contained within a two-stage superfluid helium/solid neon cooler. Goddard Space Flight Center is providing the ADR and helium dewar. The flight helium dewar was assembled in Sept. 1997 and subjected to extensive thermal performance tests. This paper presents test results at both the subsystem and component levels. In addition, results of the low temperature topoff performed in Japan with the engineering unit neon and helium dewars are discussed.