ESA-AOES Medialab
The Soil Moisture and Ocean Salinity
(SMOS) mission will make global
observations of soil moisture over
Earth’s landmasses and salinity over the
oceans. Variations in soil moisture and
ocean salinity are a consequence of the
continuous exchange of water between
the oceans, the atmosphere and the
land – Earth’s water cycle.
Europe launches satellite to monitor climate change
World’s first mission to study the global water cycle from Space
The world’s first satellite designed to map the saltiness of the sea and monitor water content in soil
across the planet was launched on 2 November
2009 by the European Space Agency (ESA). The Soil
Moisture and Ocean Salinity (SMOS) mission will survey these key indicators of the water cycle between
oceans, air and land. They have never before been
measured globally from Space, and SMOS will play
an important role in monitoring climate change —
and in predicting severe weather events.
SMOS was carried aboard a Rockot launch vehicle from Eurockot GmbH, which lifted off from
the Plesetsk Cosmodrome, about 200 km south of
Archangel in the north of the Russian Federation.
The satellite is now in a sun-synchronous orbit some
760 km above Earth, controlled on behalf of ESA
by the Centre National d’Etudes Spatiales (CNES)
in Toulouse, France. After its equipment has been
checked and calibrated, SMOS is expected to become fully operational within six months.
It will measure the natural microwave emissions
from the Earth’s surface, which alter with moisture
levels on land or the salinity of the sea. When meteorologists know how wet the soil is, they can more
easily predict floods, droughts and water reserves, as
well as weather generally. Salty water will sink below less dense fresh water, so studying the salinity
of the oceans provides information about currents
that circulate the globe, exchanging heat and fundamentally affecting the climate. This information on
a global scale, now to be provided by SMOS, “has
long been awaited by climatologists who try to predict the long-term effects of today’s climate change,”
commented Volker Liebig, ESA’s Director of Earth
Observation Programmes, at the satellite’s launch.
Normally, detecting microwave radiation in a
timely and global manner would require an antenna
that is too large to be launched on a rocket. Instead,
SMOS is equipped with a Microwave Imaging
Radiometer with Aperture Synthesis, or MIRAS. It
ITU News  10 | 2009  December 2009
19
ESA, 2009
This Envisat image captures an enormous plankton bloom stretching across the Barents Sea off northern Europe.
Envisat acquired this image on 19 August 2009 with its Medium Resolution Imaging Spectrometer (MERIS)
instrument. MERIS’s primary objective is to provide quantitative ocean-colour measurements, but the sensor can
also serve applications in atmospheric and land-surface science.
connects an array of 69 small receivers mounted on
three arms that extend from the satellite. Together,
they can capture a 1000-km field of view to provide
a complete map of the Earth every three days — including remote areas that have not been easily monitored by ground observations. Images will be synthesized to a scale of 50 km for soil moisture or 200 km
for ocean salinity.
The innovative MIRAS device was created by
Astrium Spain, formed by EADS CASA Espacio and
Astrium CRISA (Computadoras, Redes e Ingeniería
SA). The Astrium group of companies is a wholly owned subsidiary of the European Aeronautic
Defence and Space Company (EADS). The satellite
carrying MIRAS was developed by ESA in cooperation with France’s CNES and Spain’s Centro para el
Desarrollo Tecnológico Industrial (CDTI). It is based
on the Proteus small satellite platform, designed and
built by Thales Alenia Space, of France.
SMOS is the second element of the Earth Explorer
programme that ESA is conducting to gather new
environmental data. It follows the Gravity and
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ITU News  10 | 2009  December 2009
steady-state Ocean Circulation Explorer (GOCE) satellite, launched in March 2009, and further missions
are being prepared. Cryosat-2, which will measure
the thickness of ice sheets on land and sea, is due
for launch in February 2010. It is scheduled to be
followed in 2011 by ADM-Aeolus, to study atmospheric dynamics, and the Swarm mission to monitor the weakening of the Earth’s magnetic field. Due
for launch in 2013 is the EarthCARE mission to study
clouds and aerosols.
The rocket that launched SMOS also carried into
orbit another ESA satellite: Proba-2. Like its predecessor Proba-1, it is designed to demonstrate a
range of technologies for future satellite systems
and equipment to carry out Space science. In addition, Proba-2 carries two Belgian solar physics
instruments and two Czech plasma physics experiments. The joint launch of the two satellites “will
provide Europe with new tools to better understand
our planet and climate change, as well as new technology breakthroughs,” said ESA’s Director General
Jean-Jacques Dordain.