The objective of the SMOS mission is to provide Soil Moisture (SM) and Ocean Salinity (OS) maps. Both SM and OS are key variables in climate monitoring, surface / vegetation / atmosphere transfers, and ocean / atmosphere cycles.

The SMOS spacecraft consists in a platform, based on the CNES / ALCATEL PROTEUS generic platform adapted to the mission specificities and a payload, procured by ESA. The payload is an EADS / CASA L-Band (1.4 GHz) 2D passive interferometric radiometer with a Y-shaped 3 arms synthetic aperture antenna.

The SMOS Satellite Control Centre was adapted by CNES from generic PROTEUS ground segment and is operated from Toulouse within the CNES premises. The SMOS Mission Centre dedicated to level 1 and 2 products, is located at ESAC centre (ESA) in Villafranca. The specific Data Processing Centre dedicated to level 3 and 4 products was developed by CNES and is operated by Ifremer in Plouzané (near Brest) : the CATDS.