Proliferation of Space Junk Concerns Researchers

A screenshot of the program Stuff in Space, which tracks much of the debris orbiting Earth. There are over 20,000 pieces of junk larger than a softball in orbit. Stuff In Space

Scientists are increasingly worried about orbiting space debris, and the risk that it may damage satellites and spacecraft carrying humans, like the International Space Station. Last year, for example, the ISS had to quickly move itself three times to avoid being hit. And astronauts aboard increasingly have to "shelter in place" when space junk is detected too late for the station to move out of the way. This last happened on July 16, when a piece of an old weather satellite nearly collided with the station, and those aboard had to stop what they were doing and take cover until the threat passed.

Hugh Lewis, an aerospace engineer at the University of Southampton, makes a strong case to the BBC that we are in danger of creating a situation where space junk becomes so numerous as to become self-sustaining. Under this scenario, called the "Kessler Syndrome," enough debris would keep colliding and creating new pieces of junk at a rate faster than this stuff is eliminated by eventually falling out of orbit.

According to NASA, there are now more than 20,000 pieces of junk larger than a softball in orbit, and 500,000 the size of a marble or larger. Moving at speeds up to 17,500 mph, each of these has the potential to catastrophically damage a spacecraft.

Lewis urges for more research into the matter and is encouraged by a project led by the European Space Agency called e.DeOrbit that is intended for removing a large, defunct European satellite. But that project faces key hurdles in 2016, when its approval and funding will be debated by the ESA.