Thermal Design of CryoSat, the first ESA Earth Explorer Opportunity Mission

CryoSat is the first satellite of ESA's Living Planet Programme realised in the framework of the Earth Explorer Opportunity Missions. CryoSat is a radar altimeter mission dedicated to determine trends in the ice masses of the Earth. The overall spacecraft configuration was driven by the budget constraints applicable for the opportunity mission, the high inclination orbit with drifting orbit plane and the stringent stability requirements for the radar altimeter antennas. Innovative thermal design solutions were needed for the following items:

• The instrument antennas have to comply with very stringent pointing stability requirements.
• The star trackers need to be mounted at a thermally adverse position and still have to be maintained on low temperature levels.
• The instrument electronics must be close to the antennas leaving no possibility for direct rejection of heat by radiation
• The battery has contrary temperature requests from lifetime respectively performance point of view and needs late access. The DORIS USO must be mounted on shock absorbers requiring a dedicated thermal link.

Although some new design concepts had to be established to cope with stringent requirements and constraints resulting from the use of off-the shelf hardware and a low cost launch vehicle, a thermal design within the budget constraints of an opportunity mission could be achieved.