Instruments onboard satellites are extremely precise, a strategic necessity since the data they produce is used daily by more than 300 research teams, as well as companies and public agencies, such as the French weather service Météo-France.
CryoSat is a European Space Agency (ESA) altimetry satellite, dedicated to the observation of the Earth's ice masses. Designed to last three and a half years, this mission will enable us to determine changes in the thickness of land and sea ice, with unprecedented precision, and to test forecasts of ice melting due to global warming. The satellite's orbit, at an altitude of 720 km and an inclination of 92 degrees, enables it to cover practically all polar zones.
As world leader in space altimetry, Thales Alenia Space designed and built the mission's main instrument, the Siral 2 radar altimeter/interferometer.
Based on the famous Poseidon radar altimeters, the highly innovative Siral-2 synthetic aperture radar (SAR) is a very compact assembly, weighing just 90 kilograms. It combines three measurement modes to determine the topography of land and sea ice masses, as well as ice floes and significant elevation transitions, especially between land and ice fields. It heralds a new generation of space altimetry systems because of its high resolution, enabling it to analyze the ground in swaths 250 meters wide, and use interferometry to measure gradients.
SIRAL will be able to map even the most chaotic ice fields (such as those along the coast of Antarctica) and to determine their topography by combining Synthetic Aperture Radar (SAR) and interferometer modes. In much the same way as our stereoscopic vision allows us to perceive relief, SIRAL will use two antennas and sophisticated echo processing to ‘see' the relief of ice fields within its swath. Echo analysis discriminates water from ice and yields estimates of the freeboard elevation of sea ice floes. Area plus freeboard elevation plus Archimedes'
CryoSat 2 is one of six Earth Explorer missions, and is part of the Living Planet program, like Goce and SMOS - two programs in which Thales Alenia Space is also involved.
*Siral-2 is built by Thales Alenia Space. EADS Astrium is prime contractor for the CryoSat-2 satellite.