Harpooning Space Junk...Thar She Blows....seriously blows
The European Space Agency is considering using a harpoon to snag space junk in orbit.
Low-earth orbit kinda sucks these days. There’s more than 17,000 trackable pieces of junk there larger than a Big Mac. If you include objects 1-10 centimeters wide, that number swells to an estimated half-million bits of dangerous debris. This detritus ranges from multi-ton defunct satellites to paint chips.
Paint chips don’t sound too bad, right? Orbital velocities though, especially when head-on collisions occur result in hyper-velocity impacts releasing tremendous amounts of kinetic energy. Paint chips have caused craters in the shuttle’s uber-gorilla glass windows over 100 times. A slightly bigger 1 cm long object would be equivalent to a hand-grenade…and that’s all towards the best-case-scenario end of the spectrum.
A worst-case scenario makes the movie Gravity look like a game of spitball. We may see the day when one collision starts a chain reaction of debris hitting satellites creating more debris that hits yet more satellites etc. The end result is a low earth orbit (and other orbits) filled entirely with a billion tiny bits of speedy debris with no functioning satellites and no way thru for decades or centuries until atmospheric drag de-orbits most of it naturally (or until an AI solves the problem for us).
This is finally beginning to be taken seriously. The European Space Agency is now considering an innovative approach to deal with this problem. In a move to make Captain Ahab proud, it has done preliminary tests of the ability of a special tethered harpoon to penetrate a satellite-like object with reasonably good results. The plan is to have the junk pulled in and dealt with properly.
The problem with this idea though is that any satellite designed to get close enough to debris to harpoon it would be completely impractical with any near-term technology. Orbits and velocities vary so much and are so far apart that fuel consumption to get there and match orbital speeds is a total deal breaker. It’s not like science-fiction movies where ships can quickly flit from one orbit and velocity to another around a planet. Nothing I’ve read about this specific technique addresses this issue.
As fun as this idea sounds, I think it blows harder than Moby Dick
Image Credit: Science Photo Library