October 6, 2010
ESA Climate Satellite Facing Interference
The European Space Agency (ESA) said on Wednesday it launched a behind-the-scenes campaign to shut down illicit radio and TV transmissions that have interfered with their SMOS climate satellite.
The $434 million Soil Moisture and Ocean Salinity (SMOS) satellite "has been bugged by patches of interference from radar, TV and radio transmissions in what should be a protected band," ESA said in a statement today.
"Painstaking efforts to reduce these unwanted signals are now paying off," the Paris-based agency said.
SMOS orbits at 470 miles above Earth and gauges the impact of climate change on the movement of water across land, air and sea.
Scientists realized soon after it was launched last November that interference was "effectively blinding" the satellite as it passed over parts of southern Europe, Asia, the Middle East and some coastal zones.
One of the reasons for the interference is a leak into a band of the electromagnetic spectrum that is assigned to space astronomy and Earth exploration satellites by the International Telecommunications Union (ITU).
ESA said this source came from overpowerful transmitters in adjacent bands.
Another cause for the interference is illegal transmissions by TV, radio links and networks like security systems that are blasting into the radio band.
"Also, terrestrial radars appear to cause interference," ESA said.
ESA had to embark upon "the tricky and lengthy process" of having the illegal transmissions shut down and the excessive out-of-band emissions reduced.
The agency said its first approach had been to governments in Europe, which were shutting down the devices that cause the interference.
The SMOS satellite's sister, known as Gravity field and steady-state Ocean Circulation Explorer (GOCE), has also had its share of problems.
GOCE was able to record data for three months this year, but was unable to send it back to Earth because of a malfunctioning communications link between the processor and telemetry modules on the satellite's main computer.
GOCE and SMOS are on the agency's roster of "Earth Explorer" projects to help understand more about the planet.
Investigations into ice cover, cloud cover, vertical winds and the planet's magnetic field are either in operation to be explored or planning to be put into operation.
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