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SMOS

The primary objective of the SMOS mission is to provide global observations of soil moisture over land surfaces and ocean salinity over the oceans. SMOS is also improving the characterisation of ice and snow covered surfaces.

Launch Date: 2 November 2009 (Rockot from Plesetsk, Russia)

Mission Duration: 3 years nominal lifetime, including 6 months commissioning Phase, with potential extension of 2 more years.

Configuration: The satellite comprises the spacecraft bus Proteus and the payload; the MIRAS instrument.

Payload: The Microwave Imaging Radiometer using Aperture Synthesis (MIRAS) instrument is a passive microwave 2-D interferometric radiometer (L-Band, 1.4GHz, 21cm). MIRAS consists of a central structure and 3 deployable arms. The 69 antenna elements (LICEF receivers) are equally distributed over the 3 arms and the central structure. Each LICEF is an antenna-received integrated unit that measures the radiation emitted from the Earth at L-band. The acquired signal is transmitted to a central correlator unit, which performs interferometry cross-correlations of the signals.

Mass: 670kg including 282kg for platform, 360kg for payload and 28kg for fuel.

Power: Deployable solar panels with Si-cells; Li-on battery. Platform consumption: ~300W, Payload consumption: ~375W.

Mission requirements
Soil moisture Accuracy of 4% volumetric soil moisture; Spatial resolution 35-50 km; Revisit time 1-3 days
Ocean salinity Accuracy of 0.5-1.5 practical salinity units (psu) for a single observation; Accuracy of 0.1 psu for a 10-30 day average for an open ocean area of 200 x 200 km
Mission Orbit
Type LEO, sun-synchronous, polar, circular, dawn-dusk (LTAN 6:00h)
Altitude Min 761.3/ Max 788.4 km (height of elliptical orbit)
Repeat cycle 18 days, 3 day sub-cycle
Orbits per day 14
Inclination 98.42°
Attitude control 3-axis stabilised with yaw-steering about local normal and pitch correction
Mission operations
Satellite Operations Ground segment Located at CNES in Toulouse, France, operates the spacecraft via an S-band link in Kiruna (4kbps uplink, 722kbps downlink), Sweden.
Data Processing Ground Segment Located at ESAC in Villafranca, Spain, receives payload data via X-band link (16.8 Mbps) and performs processing.
Near-real time link Located at Svalbard, Norway, receives payload data via X-Band link and transmits data to ESAC Villafranca for processing.
Archiving Short-term data storage at ESAC Villafranca (up to 1 year), long-term archive located at Kiruna.
Data dissemination Via ESAC Villafranca for science and operational users; via long-term archive at Kiruna for science users. User services coordinated via ESRIN.
Data quality Regular data quality monitoring through Quality Centre- CEC located at ESAC Villafranca.