ESA battles against illegal radio broadcasts

Posted by Emma Woollacott

The European Space Agency (ESA) has embarked on a crusade to get rid of illicit radio broadcasts that are interfering with its observations.

Soon after ESA's Soil Moisture and Ocean Salinity (SMOS) mission was launched, it became clear that in some places the data was being badly contaminated by radio-frequency interference.

At times, this interference effectively blinded the instruments. 
 
SMOS carries a passive radiometer that operates at 1400–1427MHz to capture snapshots of 'brightness temperature'.

And according to regulations set by the International Telecommunications Union, this band is reserved for the Earth Exploration Satellite Service, space research and radio astronomy.

However, SMOS data showed that this was being widely abused, particularly in southern Europe, Asia, the Middle East and some coastal zones.
 
In some cases, emissions in adjacent bands were leaking into the protected region owing to excessive power levels; but in others the culprit was illegal transmission within the reserved band.

To stamp it out, ESA has started working on getting the illegal transmissions shut down and the excessive out-of-band emissions reduced.

Tackling Europe first, this is being done case by case through cooperation with governments – and a significant number of sources of interference have already been eliminated, it says, particularly in Spain.