Japan to launch ‘suicide’ satellites to clear space junk
With space junk increasingly becoming an important problem for the functionality of the International Space Station (ISS) and commercial satellites circling the Earth’s orbit, Japanese space scientists came up with the idea of building ‘suicide’ satellites that would attach to a piece of space junk and drag it back into the atmosphere. In the process, both debris and the microsatellite would burn up due to friction. These single-use satellites are not cheap; however, the demand is definitely building up, as space agencies around the world are becoming more and more concerned with the safety of their space equipment.
Japan’s space agency (JAXA) is planning to use microsatellites to clear orbits from space junk. The robotic cleaner grabs debris with a robotic arm and then lunges down to force the dangerous pieces back into atmosphere.
The 140-kilogram device uses electrodynamics tethers to drag down the debris. The tethers are conductive wires with lengths of up to several kilometres, which can be used to generate propulsion.
The Japanese cleaner approaches debris, attaches itself to it with a robotic arm, and then moves to a lower orbit, unwinding the tether from a reel. An electric current is generated in the tether, which interacts with Earth’s magnetic field to create drag, which slows down the debris making it re-enter the atmosphere and subsequently burn up. The satellite, of course, is destroyed in the process as well.
JAXA estimates the cost of a single kamikaze cleaner at $US 4 million. They believe the demand for them will increase, as national space agencies start to take more effort do deal with the problem of space junk. On March 12 the crew of the International Space Station had to evacuate to the docked Soyuz spacecraft when a small piece of trash threatened to collide with the station.
Earth orbits are already heavily packed with pieces of spacecraft, outdated satellites and even tools lost by the ISS crews. NASA estimates that 13,000 large space objects more than 10cm long are circling the Earth, and less then a thousand of these are functioning. Dozens of millions of smaller fragments are free floating in space.