Space junk is a huge problem. In fact, if we don’t do something about the more than 20,000 objects—from defunct satellites to paint chips—that are orbiting Earth, we may one day be unable to leave the planet at all.
Luckily, scientists are on the case. In the UK, a team at Airbus is developing a charmingly lo-fi method of removing large pieces of junk from orbit: a giant harpoon. The harpoon, which is about a meter long, would be attached via a strong tether to a spacecraft which would follow it as it punctured space trash. The spacecraft would then tow the junk back down to Earth, where it would burn up in the atmosphere.
To test their invention, the researchers have been shooting their harpoon in the lab, using compressed air, at sheets of metal that are 3 cm thick aluminum composite honeycomb panels.
“The harpoon goes through these panels like a hot knife through butter,” advanced project engineer Alastair Wayman told the BBC. “Once the tip is inside, it has a set of barbs that open up and stop the harpoon from coming back out. We’d then de-tumble the satellite with a tether on the other end.”
“Many of these targets will be tumbling and if you were to use a robotic arm, say, that involves a lot of quite complex motions to follow your target,” Wayman said. “Whereas, with the harpoon, all you have to do is sit a distance away, wait for the target to rotate underneath you, and at the right moment fire your harpoon. And because it’s a really quick event, it takes out a lot of the complexity.”
The biggest quarry out there for this new invention—the Moby Dick of space junk, if you will—is the broken Envisat Earth observation satellite, an eight ton hunk of metal that’s floated uselessly for six years now.
“If we can design a harpoon that can cope with Envisat, then it should be able to cope with all other types of spacecraft including the many rocket upper-stages that remain in orbit,” Wayman told the BBC.
Airbus’ harpoon will soon be put to the test. A miniature version of the device will be sent into space next month with a mission by RemoveDebris, another group focused on the space junk problem. This test mission will release its own piece of junk and then try using both a net and the harpoon to capture it.
Back at home, the big harpoon still needs more testing. But if it works, it could free up a significant amount of space in Earth’s orbit
