CryoSat-2 is a satellite with a single mission objective – therefore, the selection of its orbit and basic characteristics has been entirely driven by the scientific requirements.
Unlike most remote sensing satellites, CryoSat-2's orbit is not to be Sun-synchronous, but will go through frequent eclipse phases. This has presented some challenges in the satellite design; all parts will at some time be exposed to the full heating power of the Sun, while at other times parts of the satellite will be in permanent shadow for weeks on end.
CryoSat-2 does not have any deployable solar panels; in fact the satellite has no moving parts at all, except for some valves in the propulsion system. This has enabled a very significant cost saving, but does pose some problems for the provision of adequate solar power in CryoSat-2's unusual orbit. The solar panels are fixed to the satellite body, forming a 'roof' at a carefully optimized angle, which provides adequate power under all orbital conditions and still fits within the launch vehicle.
The other area that receives particular attention has been the mounting of the two SIRAL antennas. The baseline on which the SIRAL antennas were mounted has to be completely stable and has to ensure minimal thermal expansion. Any distortion will lead to errors in the assumed location of the echo and hence the elevation of the surface of the ice. The challenge has been met by designing the structure to be intrinsically stable and providing auxiliary attitude measurement sensors, in the form of star trackers, mounted directly onto the antenna bench structure.
Last update: 22 January 2010