Airbus Defence and Space


Measuring the Earth’s water cycle

The SMOS (Soil Moisture and Ocean Salinity) programme, the second Earth Explorer Opportunity mission selected under ESA’s Living Planet programme, has been designed to observe and monitor two important variables of the Earth’s climate system – soil moisture over landmasses and salinity over the oceans. These two parameters are of key interest as they are fundamental for understanding the planet’s global water cycle, and thus for the creation of atmospheric, oceanographic and hydrological prediction models.

Airbus Defence and Space Spain designed and built the SMOS mission’s single-instrument payload and the innovative two-dimensional interferometer MIRAS (Microwave Imaging Radiometer using Aperture Synthesis). A real technological challenge, it employs measuring techniques that have never before been used in space. From a scientific, technological and industrial point of view, MIRAS is the most significant programme developed for ESA in Spain to date.

The SMOS satellite was launched on a Rockot vehicle from the Russian Plesetsk Cosmodrome in November 2009.


Fact Sheet

 Customer European Space Agency
 Mission To measure soil moisture over land & salinity over oceans
 Orbit Sun-synchronous, dawn/dusk, quasi-circular orbit at altitude 758km.
06.00 hrs local solar time at ascending node
 Spacecraft Lead by Thales Alenia Space Industries. A Proteus platform adapted to the needs of the SMOS mission
 Payload Lead by Airbus Defence and Space Spain. MIRAS - Microwave Imaging Radiometer using
Aperture Synthesis (Passive microwave 2D-interferometer)
 Features • Frequency: L-band
• Number of receivers: 69
• Receiver spacing: 18.37cm
• Polarisation: H & V (polarimetric mode optional)
• Spatial resolution: 35km at centre of field of view
• Tilt angle: 32.5 degrees
• Radiometric resolution: 0.8 - 2.2K
• Angular range: 0-55 degrees
• Instrument data rate: 89kbps H & V pol
 Launch Mass 658 kg (platform 275 kg, payload 355 kg, fuel 28 kg)
 Dimensions Cylinder 2.4m high and 2.3m in diameter
 Launch Date 2009
 Mission Duration Three years (including a six-month commissioning phase) with a possible two-year extension
 Airbus Defence and Space Responsibilities Payload Prime & MIRAS Instrument


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Earth ObservationEnvironmentSMOSClimate