As if there weren't already enough vaguely crazy schemes to start taking care of the space junk problem, Astrium UK wants to outfit a bunch of spacecraft with harpoons and send them chasing down rogue satellites.
Harpoons seem like a rather, uh, dramatic way to go about disposing of rogue satellites. And when we say "harpoon," it's not some kind of technical term for a fancy new technology: basically, we're talking about a good ol' fashioned Moby Dick or 20,000 Leagues Under the Sea style harpoon:
Each of these harpoons would only be 30 centimeters long, which is big enough to securely penetrate and latch on to defunct satellites, but not big enough to take a chunk out of them. It would be fired from about 20 meters away, and once the harpoon embeds itself in the junk satellite, a small thruster on the other end of the cable fires, slowing the satellite down enough to send it plunging in a death spiral down into the atmosphere. Meanwhile, the spacecraft that fired the harpoon (which would be equipped with a whole bunch of them) moves off to stalk its next target.
It's obviously not going to work to try to harpoon all the bajillions of little tiny particles of junk that are floating around up there: harpoons will only be useful for relatively large satellites and spent rocket stages and such. This is particularly important, however, since satellites smashing into other satellites has the potential to create an orbital space junk cascade that could render parts of Earth orbit extremely dangerous, so taking care of all of those old and busted sats as quickly as possible is (or should be) a high priority.
The harpoon system is currently undergoing trials here on the ground (which is why the schematic above has fins), but we're already a picturing a future where satellites loaded with harpoons are sailing through space, mercilessly harpooning every piece of junk that they find, including dead satellites, confused whales and bowls of petunias.