“Researchers in Australia want to use lasers to track wayward particles of space junk, and even shove them out of the way before they cause problems,” IEEE Spectrum reports. “NASA says there are more than half a million pieces of debris, from disused satellites to flecks of paint, speeding around the earth at up to 17,500 mph.” The method is ultimately an interstellar version of the sport of curling, where athletes “sweep” the ice to maximize the travel of a stone.

“Celine D’Orgeville, a professor at Australian National University’s Research School of Astronomy and Astrophysics in Canberra and her colleagues propose applying adaptive optics, a technique widely used in astronomy, to the problem of tracking the smaller pieces of debris, between 1 and 10 cm in size, which can be hard to see. Adaptive optics lets astronomers overcome the atmospheric turbulence caused by changes in pressure and temperature that makes the stars twinkle.”

“Using the system, D’Orgeville and her colleagues can fire a series of infrared laser pulses at the orbiting flotsam to measure where they are and where they’re headed. Without adaptive optics, they wouldn’t be able to focus the infrared laser well enough to find small objects. Knowing the path of the debris, they can warn, say, a communications satellite to alter its orbit slightly to avoid getting hit.

But the team wants to go further than that, and use yet another laser to actually push some of the debris out of the way. If they discover that two tiny pieces of space junk were headed for a crash—which might result in more, harder-to-track debris—they could fire a 20-kilowatt infrared laser at one of the pieces. The light pressure from the laser would be enough, after a few shots, to gently nudge the junk onto a different trajectory. “It’s not going to destroy the debris or anything, but at least you can move it out of its way,” she says.”