What do you do with 6,000 tons of space junk traveling at thousands of miles an hour? Harpoon it of course. It might sound like a scenario straight off the pages of a science fiction novel but it is a suggested solution to an increasing and potentially costly problem in space — that of debris littering low earth orbit. The harpoon plan is one of a range of options being discussed by scientists at a forum in Germany next week, and aimed at finding a way of tackling space debris that threatens commercial operations. Engineer Jaime Reed, who is leading the harpoon project for the space technology company Astrium, explains that if a rogue satellite hits another, not only does it ruin the mission but it creates more debris and propagates the problem. This run-away scenario is often called the Kessler Syndrome, named after NASA’s Don Kessler who first highlighted the risk.
“There’s a lot of space debris — 6,000 tons in orbit — that could pose a threat,” said Reed.
“Perhaps unwittingly, the average person relies a lot on space — GPS in their phones, telecoms, TV, weather forecasts — they are things people expect to have,” he said.
“Space debris could very easily take out some of those satellites — it would have a real impact on people’s lives.”
Astrium’s plan to tackle defunct satellites is to use an unmanned chase spacecraft to get in range, fire a barbed harpoon into the body of the rogue hardware and then use a smaller propulsion unit attached to a tether to tow it back towards the atmosphere where it will burn up safely on re-entry.
“Because the harpoon we are using is very light and the chase satellite more than a ton, momentum is very tiny… it’s a small recoil,” said Reed. …
Video animation here. Great idea. It is extra interesting due to the possibility that a harpoon system could be used on working enemy satellites, not just junk, thus making it a space based weapon. Do most satellites have thrusters for repositioning that would be able to fight off a harpooning that tried to drag them down to Earth?