The Living Planet Program : Soil Moisture and Ocean Salinity (SMOS)

Mission objectives

The scientific objective of this mission is to obtain a better estimate of the spatio-temporal water budget at the global scale and ocean/atmosphere interactions.

• Over continental surfaces, it is necessary to estimate the soil surface humidity for global circulation models and boundary conditions for large hydrological models. Sensitivity analyses show the importance of knowing a precise value on the soil surface humidity for precipitation field reconstruction. Moreover, new approaches permit the estimation of the root zone water content. Finally, multi-angular and dual polarization measures from SMOS will allow a quantification of the vegetation water content.
• Over the oceans, it is necessary to estimate the salinity which is a very important variable for ocean circulation dynamics and for ocean/atmosphere coupling.

Project status

This project was submitted to ESA by the CESBIO in response to the call for proposals " Earth Explorer Opportunity Missions "in November, 1998.  It was classed second and therefore it was selected. In mid-January 2004, the project passed into phase C/D at ESA. Opportunity mission scheduled for launch in 2009.

SMOS was launched nominally the november 2, 2009.

SMOS in-orbit commissioning as been on track since the succesful launch of the satellite on November 2nd, 2009. Following accurate injection, payload arms deployment and fine tuning of the orbit, the first period was dedicated to PROTEUS bus. Full review of platform capability being conducted, after the instrument was switched on on November 17th, 2009, mission commissioning per se was started.

After a full functional health check of all calibration and acquisition modes, instrument characterisation has begun in sequences, each of which yielding an improvement in data quality. Only concerns have been with one of the local oscillator, which had to be switched to backup side, and with strong presence of RFI over some specific areas.

Current status is that the instrument is behaving better than expected and studies are being initiated to mitigate RFI impact. For more information, details in real time on the in-orbit are published on the SMOS_blog