Australia Is Building a Laser To Shoot Junk Out of Orbit

We can potentially solve our orbital litter problem from the ground.

Image: NASA/Wikimedia Commons

So far, the plans to clean up space have been, for lack of a better term, a little out there. We’ve got the European Space Agency considering using nets, harpoons, and tentacles, while Switzerland’s developing a kamikaze janitor satellite. Now, there’s this: The Australian government is developing technology that they think will allow us to deorbit small bits of space debris with ground-based lasers.

It’s the first time anyone has proposed a solution to our space junk problem that doesn't involve leaving the comfort of our own planet. Friday, the Australian government announced it would be spending $20 million to create the Cooperative Research Centre for Space Environment Management, which it plans to open in the next couple months, according to Matthew Colless, director of the Australian National University’s astronomy school. NASA, Lockheed Martin, and several other partners will kick in an additional $70 million, so they are very serious about this plan.

But enough about the center. Here’s how it’s going to work. Colless says that, in the near term, the center will work on something called adaptive optics to allow astronomers to better track space junk. 

“Essentially, it’s a technique to take the blur out of the atmosphere. You’re using lasers and mirrors to correct the blur from the atmosphere so we’re able to track more bits of space junk more accurately,” he said.

That in and of itself would be useful: Right now, our basic strategy is to maneuver satellites around the 500,000 pieces of debris that make up low Earth orbit. That’s impossible if you don’t know where they are. But Colless says the center has much more ambitious goals.

“Long term, we want to try to manipulate things so they’ll deorbit,” he said. 

That, of course, is the goal. We’re going to need to get these things out of orbit somehow, and we haven’t had a good way of doing it. Using the same technology that will be used to track the junk, Colless says you can theoretically power up the laser even more to essentially push small pieces of junk lower and lower until they eventually fall out of orbit altogether.

“You up the power of the laser enough so that the photon pressure will slow it down in orbit,” he said. “If you hit it hard enough, it will deorbit due to the atmospheric drag.”

The technology isn’t there yet, but that’s what the shiny new, $90 million center is for.  

The deorbiter lasers are only going to work on very small pieces of junk, but those are perhaps even more important than the larger ones. 

“They’re traveling many many kilometers per second; they’re essentially bullets. You're essentially walking through crossfire all the time,” he said. The lasers would be used in conjunction with some of those other, space-based ideas that would remove the larger pieces. "You're going to need those for the big stuff, but maybe we can have many of these [lasers] and they can work together. This could be an efficient way of solving this."

Australia is perhaps an unlikely country to worry about space junk—they haven’t launched a particularly large number of rockets into space, after all. But then again, maybe it makes perfect sense: In 1979, Skylab, a pretty huge piece of space junk, fell on the country (no one was hurt). So maybe they’re like a roommate that has finally gotten so sick of your sloppy ways that they’ve decided to just to just clean up after you, all passive aggressive-like. But in the end, you’re just glad someone did it.