Developments in Turbo Brayton technology for low temperature applications

A single stage reverse Brayton cryocooler using miniature high-speed turbom achines recently completed a successful space shuttle test flight demonstra ting its capabilities for use in cooling the Near Infrared Camera and Multi -Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The NICM IOS CryoCooler (NCC) is designed for a cooling load of about 8 W at 65 K, a nd comprises a closed loop cryocooler coupled to an independent cryogenic c irculating loop. Future space applications involve instruments that will re quire 5-200 mW of cooling at temperatures between 4 and 10 K. This paper di scusses the extension of Turbo Brayton technology to meet these requirement s. (C) 2000 Elsevier Science Ltd. All rights reserved.