Space is quickly becoming the final frontier for man-made junk, a celestial repository for more than 7,600 tons in orbit. Dormant satellites, defunct boosters and bits of shrapnel derived from satellite collisions travel at hypersonic speeds in the same orbits as active satellites, posing risks to existing equipment and planned missions.

Different approaches are being pursued to improve extraterrestrial solid waste management, including the use of magnetic grappling to knock debris out of orbit or tethered nets to capture derelict satellites. A European Schematic of the RemoveDEBRIS system. Source: University of SurreySchematic of the RemoveDEBRIS system. Source: University of SurreyCommission-funded consortium recently demonstrated that an experimental system can perform cleanup duties: the RemoveDEBRIS spacecraft harpooned a piece of simulated debris in low Earth orbit. The technology demonstrator satellite deployed a target panel at the end of a 1.5 m (4.9 ft) boom, then skewered it with a metal harpoon traveling at 20 m/s (44.7 mph, 72 km/h) as part of a series of trials to test various space debris elimination techniques.

The space harpoon, which consists of a launcher, a tethered harpoon and a flip-out locking mechanism to secure the target on penetration, was deployed in the third of these experiments. The previous two tested a net launcher for ensnaring satellites and a LiDAR and camera-based vision navigation system to identify space debris. The fourth and final experiment, slated for March, is a sail that will increase orbital drag and cause RemoveDEBRIS to plummet into the Earth's atmosphere, where it will burn up.

Participants in the RemoveDEBRIS consortium are Surrey Space Centre (U.K.), ArianeGroup (France), SSTL (U.K.), Airbus (U.K., France and Germany), CSEM (Switzerland), Innovative Solutions in Space (Netherlands) and Stellenbosch University (South Africa).

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