Sentinel-3

The Sentinel-3 satellite fits into the GMES program, a joint project between Esa and European Union. Dedicated to Earth and Ocean studies, it will be launched in 2012. This project is the European answer to the needs still growing related to the global environment.

Sentinel-3 belongs to a series of five satellites :

• Sentinel-1 will ensure the continuous radar measurements of SAR operated by ERS and Envisat satellites,
• Sentinel-2 will be an optical satellite for spectral observations,
• Sentinel-3 will be devoted to the Earth monitoring and operational oceanography,
• Sentinel-4, in a geostationary orbit,  will be dedicated to the atmospheric pollution,
• Sentinel-5 in a low orbit, will be used for atmospheric chemistry.

The Sentinel-3 payload shall incorporate an advanced radar altimeter, a multi-channel optical imager, some appropriate components for high-accuracy atmospheric water vapor, aerosols, and ionospheric corrections, and at last, a location system for precise orbit determination (especially with Doris system).

The altimeter shall be able to operate in two modes : a low resolution mode over homogeneous surfaces like oceans and a high resolution mode over sea ice or for mesoscale applications.

Main orbit features agree with scientific requirements: a high inclination polar orbit, a sun-synchronous orbit and a complete global coverage every 1 to 3 days for optical instrumentation.

Mission's objectives are applied to the ocean, to land surfaces and to cryosphere. For each of these domains, primary variables would be : Sea-Surface Height (SSH), Sea-Surface Temperature (SST), Ocean Color (OC), Land Color (LC), Water Surface Level on rivers and lakes and elevation/thickness of floating sea-ice.