Physics Today: A Russian Rokot launcher has successfully taken off from the Plesetsk Cosmodrome with Europe's Soil Moisture and Ocean Salinity satellite on board.
SMOS, a small 658-kg satellite, will provide the first global maps of the amount of moisture held in soils and of the quantity of salts dissolved in the oceans.
"Salinity is one of the drivers for the Thermohaline Circulation, the large network of currents that steers heat exchanges within the oceans on a global scale," says Volker Liebig, ESA's director of Earth observation programs. "Its survey has long been awaited by climatologists who try to predict the long-term effects of today's climate change."
The satellite was developed by ESA in cooperation with France's CNES and Spain's Centro para el Desarrollo Tecnológico Industrial (CDTI).
Its only instrument is called the Microwave Imaging Radiometer using Aperture Synthesis (MIRAS). The device works by connecting together 69 receivers mounted on three deployable arms to measure the temperature of the reflection of Earth's surface in the microwave frequency range. This temperature is linked to both the actual temperature of the surface and its conductive characteristics, which are in turn linked to soil moisture for land surface and to water salinity for sea surface.
"The data collected by SMOS will complement measurements already performed on the ground and at sea to monitor water exchanges on a global scale," says Liebig. "Since these exchanges—most of which occur in remote areas—directly affect the weather, they are of paramount importance to meteorologists."
SMOS is the second satellite launched under ESA's Earth Explorer program to gather new environmental data. It follows the Gravity and steady-state Ocean Circulation Explorer (GOCE), which was launched in March.
Next February, Cryosat-2 will be launched to measure the thickness of the ice sheets. This will be followed in 2011 by ADM-Aeolus—designed to study atmospheric dynamics—and the Swarm mission to monitor the weakening of Earth's magnetic field. Finally in 2013 the EarthCARE mission will study clouds and aerosols.
Dual payload
SMOS was not the only payload onboard the Rokot launcher: the 135 kg Proba-2 (right image) an experimental European satellite designed to observe the Sun and study the local space plasma environment was also on board.
"Like its predecessor Proba-1, [the satellite] is aimed at demonstrating a wide range of technologies, both for future satellite systems and for space science instruments," says Michel Courtois, ESA's director of technology and quality management. "Among these is a demonstration model of a miniaturised startracker developed for ESA's BepiColombo mission to Mercury and the future Solar Orbiter probe."
Other technologies to be demonstrated include a digital Sun sensor, miniaturized wide-angle camera, fiber sensors, a high-precision magnetometer, a dual-frequency GPS space receiver, a xenon-fed resistojet thruster, a cold gas generator, and many more.
In addition, Proba-2 carries two Belgian solar physics instruments and two Czech plasma physics experiments.
Two more Proba missions are already in the design and development phase. Proba-V will carry a vegetation multispectral sensor to monitor vegetation cover, and Proba-3 is due to demonstrate formation flying.
In orbit
Both satellites are currently circling Earth on their respective Sun-synchronous orbits, at an altitude of some 760 km in the case of SMOS and 725 km in that of Proba-2.
Early in-orbit operations have begun to check the satellites before commissioning them for operations. Proba-2 is planned to reach operational status in two months' time.
The SMOS will take longer to check and calibrate, and the spacecraft will enter fully operational mode within six months.
"We are extremely pleased with this double 'lucky strike' that will provide Europe with new tools to better understand our planet and climate change, as well as new technology breakthroughs that will enhance the competitiveness of European industry on the world-wide market, thus contributing to the global economy," said Jean-Jacques Dordain, ESA's director General, witnessing the launch from Plesetsk.
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