SMOS Earth's water monitoring mission
- Paper number
IAC-06-B1.2.05
- Author
Mr. Andres Borges, EADS CASA Espacio, Spain
- Coauthor
Mr. Achim Hahne, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Mr. Kevin McMullan, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2006
- Abstract
SMOS (Soil Moisture and Ocean Salinity) is the second Earth Explorer Mission of Opportunity within the European Space Agency (ESA) Living Planet Program. The purpose of the SMOS mission is to provide soil moisture and ocean salinity maps from space. These two geophysical parameters are of key importance for improving climatologic forecasts, increasing the understanding of water cycle, providing new approaches to knowledge on the phenomenon of climatic change and monitoring the planet’s fresh water reserves. The mission is comprised of a satellite in a low sun synchronous orbit, with an altitude of 755 Km and a revisit time of 3 days, that measures the electromagnetic noise generated by Earth at L-band (1.4 GHz) with a spatial resolution of 50-100 Km and radiometric sensitivity of 5K. SMOS detects the electromagnetic radiation at L band where microwave theorists have encountered a direct relationship between soil moisture and ocean salinity with Earth emissivity. SMOS single instrument is a innovative 2D synthetic aperture interferometric radiometer. Synthetic aperture interferometry is an alternative to real aperture instruments, since this permits the synthesis of a theoretical antenna of very large aperture, starting from a diverse collection of small antennas, which achieves an instrument weight / geometric resolution ratio. The system acts as a radio camera, and as the satellite moves forward, a wide swath is covered without mechanical movement by correlating the signals of every pair of receiver units (LICEF) to create a larger synthetic antenna in order to increase the image resolution The LICEF units capture the noise from the Earth. After the integration time, all the LICEF outputs, in digital format are sent to correlator-computer unit that is in charge of generating the synthetic antenna by correlating the signals. SMOS has three arms in “Y” form and a central structure that supports them. Each arm is comprised of three segments that are connected by a hinge. The arms are folded to the sides of the central structure during launch. There are in total 66 LICEF units and 3 noise injection radiometers (NIR) spread over the segments and the central structure of the satellite. All NIR and LICEF units have two polarisations antenna (H and V). SMOS has two main operational modes: - Observation mode, to measure the geophysical parameters. The observation mode can be either dual polarisation or full polarisation - Calibration mode, to calibrate the LICEF units. At present the flight model is being integrated and launched is foreseen for Autumn 2007 with a life time of 3/5 years. EADS CASA Espacio is the prime contractor for the SMOS PLM. A second generation of SMOS satellite is in study to continue the supply of soil moisture and ocean salinity maps. The SMOS Ops (operational satellites) will be based on the current configuration with some improvements in pixel resolution and revisit time. The SMOS Ops scenario includes 3 recurrent satellites with overlapping life time and the first launch should happen in early 2011.
- Abstract document
- Manuscript document
IAC-06-B1.2.05.pdf (🔒 authorized access only).
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