Scientists Want to Use Lasers to Shoot Down Space Junk

The idea sounds farfetched, but it may be better than previous solutions

orbital debris
An illustration of some of the debris in low Earth orbit NASA

Hundreds of thousands of pieces of trash litter the space around Earth. Ranging from defunct satellites to chips of paint smaller than 1 centimeter, some pose more danger than others. Collectively, however, the debris field is getting populated enough that some researchers think it may keep humans Earthbound.  Scientists are working out better ways to track space debris and coming up with potential solutions to the problem. The latest of these ideas would equip the International Space Station with powerful lasers designed to zap the trash away.

The problem of space junk has been recognized for years. In 1972, NASA researcher Donald Kessler predicted that collisions between chunks of trash in space could spiral out of control and create many thousands more hazards whizzing around in orbit. 

A group from the Riken Institute in Japan recently detailed their laser-powered solution in the journal Acta Astronautica. Their plan would harness the power of the Extreme Universe Space Observatory's (EUSO) super-wide-field telescope, already onboard the ISS, reports Jessica Mendoza for The Christian Science Monitor. That telescope could spot pieces of space junk and a yet-to-be mounted laser could knock them out of orbit. This means that the laser wouldn't blow up old satellites in a showy shower of smaller space debris. Instead, the pulses would nudge the junk lower so that they enter the Earth’s atmosphere and burn up. 

The EUSO telescope was originally designed to detect high-energy cosmic rays streaking into the Earth’s atmosphere at night. "We realized that we could put it to another use," Toshikazu Ebisuzaki, one of the paper authors, says in a statement. Should the laser-plan move forward, the telescope would be doing double duty. "During twilight, thanks to EUSO’s wide field of view and powerful optics, we could adapt it to the new mission of detecting high-velocity debris in orbit near the ISS."

This isn’t the first time that a space agency has floated the idea of using lasers to clear space junk. However, the previous proposal kept lasers on the ground. Other ideas have included creating a "wall of water" to remove space trash. Future satellites could be equipped with giant balloons or solar sails that would unfurl and drag them down to burn up in the atmosphere as soon as their useful life played out.

The new proposal, the Riken researchers argue, would be more affordable and accurate than the ground-based approach. They plan to test their idea using a smaller version of EUSO’s telescope and a mini laser.

The fact that the laser would be mounted on the ISS might help allay concerns that such a powerful tool could be used as a weapon to take down other countries satellites. This was a criticism leveled at the previous laser idea, reports Adam Mann for

In any case, many researchers agree that someone needs to make a move soon against space junk. Meanwhile, every time something new is launched into space, more debris are sent into orbit. As Kessler told Sarah Laskow for The Boston Globe, "Even if we don’t put anything else in orbit, in the long term, everything is going to collide with one another."

Get the latest stories in your inbox every weekday.