Cleaning Up Space JunkEngineering360 News Desk | December 12, 2016
A Japanese space mission aims to help clean up the massive amount of space junk left behind since the Soviet Union launched Sputnik into orbit in October 1957.
In early December, the Japan Aerospace Exploration Agency (JAXA) launched a cargo ship, named “Kounotori” (Japanese for stork), equipped with a specially designed space junk collector. Kounotori 6’s mission is to supply the International Space Station; the cleanup operation is scheduled to occur before the ISS rendezvous.
Scientists estimate that 100 million pieces of junk – satellites, jettisoned rocket stages, fragments, and human debris like a wrench and a toothbrush – orbit our planet. This junk poses a hazard to current and future space flights, both manned and unmanned.
Although spacecraft are protected by Whipple shields, debris striking elements like solar panels can cause damage. NASA has calculated that half of the risk to space shuttle missions came from debris. Sometimes junk falls to Earth, posing a potential problem to structures or people on the ground.
The Japanese space agency will deploy a 2,300-foot-long electrodynamic tether which will generate electricity as it swings through Earth’s magnetic field. The idea is that the electric field will attract and slow down debris. When velocity decreases, the junk should drop into successively lower orbits, eventually burning up as it falls through Earth’s atmosphere.
The tether is the result of 10 years of research. JAXA has as a partner on this venture Nitto Seimo, a Japanese fishnet manufacturer. The tether uses the company's fishnet plaiting technology, but it was difficult to intertwine the thin materials.
In future missions the tether will snare individual objects. A JAXA spokesperson says that the agency would like to run regular missions by the middle of the next decade. Ironically, the Kounotori 6 mission itself will leave space junk behind, two rocket stages and a payload fairing.