A TEAM OF British scientists has proposed a method for detecting the growing amount of space 'junk' - the debris from defunct rockets and satellites - that threatens to collide with satellites orbiting Earth.
The researchers have completed a study for the European Space Agency to build a sophisticated telescope that can automatically detect and monitor some of the smallest debris in space.
ESA's space operations centre at Darmstadt in Germany is so concerned about space debris that it has asked Sira, a British instrumentation company, to design a device that could be fitted to a 1m-wide optical telescope for detecting small objects moving in the satellite orbits.
Dan Lobb, head of the Sira research team, said a device could be built to detect and track objects as small as 20mm in diameter and 500km (310 miles) from Earth.
'The main purpose of the proposal is to quantify the problem in order to find out just how much debris there is out there,' he said. Scientists are particularly concerned at the amount of debris circulating in very high orbits, some 36,000km from Earth, where expensive 'geostationary' satellites used for telecommunications and surveillance are permanently parked.
Radar can be used to track most debris nearer to Earth, he said, but it is not effective beyond about 500km. 'For geostationary orbit we may do a complete survey of the sky of what can be seen from one point on Earth with our optical telescope.'