The Space Surveillance Telescope (SST), developed by the US Defense Advanced Research Projects Agency (DARPA), is to be used to protect US and international assets and commercial and international satellites in orbit around Earth. Researchers are currently tracking an estimated 22,000 artificial objects that are orbiting Earth, from small bits of debris to large satellites. That number is expected to triple in the next 20 years. Even a centimetre-sized piece of debris can cause considerable damage to crucial weather, communication or missile-warning systems.
The US Air Force keeps a catalogue of all known orbiting objects through its Space Surveillance Network, an integrated system of ground- and space-based telescopes and radar. The network tracks debris to anticipate possible impacts, but better surveillance is needed to cope with the increasing number of objects, says Laing. The SST would focus mostly on the region in which objects in geosynchronous orbit reside, about 35,000 kilometres from Earth.