Development of a 4K Sorption Cooler for ESA’s Darwin Mission: System-Level Design Considerations

ESA’s Darwin mission is a future space interferometer that consists of six free-flying telescopes. To guarantee a proper mechanical stability of this system, hardly any vibration of the optical system with integrated cryocoolers can be tolerated. This paper presents the system design of a 4.5 K, 10 mW vibration-free sorption cooler chain, of which the helium stage is currently in development under an ESA-TRP contract. A sorption cooler is a favorite option because it has no moving parts and it is, therefore, essentially vibration-free. A two-stage helium/hydrogen cooler is proposed which needs 5 Watts of input power and which applies two passive radiators at 50 K and 80 K. The paper includes the following aspects: system modelling, radiator configurations, activated carbons, different multi-stage cooler options, and integration aspects of the compressor cells with the radiators.

[1]  T. Brown,et al.  Detection of Planetary Transits Across a Sun-like Star , 1999, The Astrophysical journal.

[2]  Johannes Faas Burger,et al.  Vibration-free 5 K sorption cooler for ESA's Darwin mission , 2002 .

[3]  Miko Elwenspoek,et al.  Construction and Operation of a 165K Microcooler with a Sorption Compressor and a Micromachined Cold Stage , 2003 .

[4]  W. L. Swift,et al.  Reverse Brayton Cryocooler for NICMOS , 2002 .

[5]  R. Levenduski,et al.  Flight Demonstration of the Ball Joule-Thomson Cryocooler , 2002 .

[6]  Nicola Rando,et al.  Cryogenics in space - a review of the missions and technologies , 2000 .

[7]  Lawrence A. Wade,et al.  Low-power, zero-vibration 5 K sorption coolers for astrophysics instruments , 2002 .

[8]  Erwin Hondebrink,et al.  Improvements in Sorption Compressor Design , 2005 .

[9]  Mark V. Zagarola,et al.  Advanced Developments for Low Temperature Turbo-Brayton Cryocoolers , 2002 .

[10]  Pradeep Bhandari,et al.  Initial test performance of a closed-cycle continuous hydrogen sorption cooler, the Planck sorption breadboard cooler , 2003 .

[11]  M. Donabedian,et al.  Spacecraft Thermal Control Handbook, Volume II: Cryogenics , 2004 .

[12]  Herman J. Holland,et al.  Thermodynamic considerations on a microminiature sorption cooler , 2002 .

[13]  D. Queloz,et al.  The New Planetary Systems , 1999 .

[14]  D. S. Glaister,et al.  Low-Temperature, Low-Vibration Cryocooler for Next Generation Space Telescope Instruments , 2002 .

[15]  G. Davey.  Review of the Oxford Cryocooler , 1990 .

[16]  J. Mariotti,et al.  Planets outside the solar system : theory and observations , 1999 .