The growing cloud of space junk surrounding the Earth is a hazard to spaceflight, and will only get worse as large pieces of debris collide and fragment. NASA space scientists have hit on a new way to manage the mess: Use mid-powered lasers to nudge space junk off collision courses.
The U.S. military currently tracks about 20,000 pieces of junk in low-Earth orbit, most of which are discarded bits of spacecraft or debris from collisions in orbit.
The atmosphere naturally drags a portion of this refuse down to Earth every year. But in 1978, NASA astronomer Don Kessler predicted a doomsday scenario: As collisions drive up the debris, we’ll hit a point where the amount of trash is growing faster than it can fall out of the sky. The Earth will end up with a permanent junk belt that could make space too dangerous to fly in, a situation now called “Kessler syndrome.”
Low-Earth orbit has already seen some scary smashes and near-misses, including the collision of two communications satellites in 2009. Fragments from that collision nearly hit the International Space Station a few months later. Some models found that the runaway Kessler syndrome is probably already underway at certain orbit elevations.