WIDE RANGE THERMAL TEST FACILITY FOR JUICE LARGE APPENDAGES

摘要

JUICE - JUpiter ICy moons Explorer - is the first large-class mission in ESA's Cosmic Vision 2015-2025 program. Planned for launch in 2022 and arrival at Jupiter in 2029, it will spend at least three years making detailed observations of the giant gaseous planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. The number of thermal cycles and the temperature range imposed by the mission are quite large and classical testing systems with cold screens and radiative exchanges involve prohibitive tests durations. It is hence necessary to conceive a new test facility in order to fulfill a wide temperature range with reduced tests durations, optimizing the test cost not only by shortening the test phase but also by automation of the facility. A dedicated facility, based on temperature controlled low pressure Helium environment is presented. The additional gaseous conductive link exchange complies with a 43-433K temperature range, in an acceptable uniformity and reduced thermal cycle duration. The heating and the cooling process is described together with the safety devices developed and implemented for avoiding prohibitive overpressure between the inner Helium pressurized environment and the outer vacuum envelope. The mechanical design is illustrated with finite element thermo-elastic results. Finally, the various thermal cycle durations will be shown based of assumed thermo-optical properties and conductive heat exchange temperature dependent parameters.