The aeronautics company Airbus is currently testing a three-foot harpoon they hope will catch the nonfunctional satellite Envisat and pull it back to Earth. This particular proposal may also address the rising problem of space debris. “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,” project engineer Alastair Wayman told the BBC.
Prior to launch, the harpoons are being tested by being shot at high speeds into various materials that are used to build satellites. “The harpoon goes through these panels like a hot knife through butter,” said Wayman. “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.” In the end, the ancient technology of the harpoon may prove more effective than robotic arms in space. “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,” explained Wayman.”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.”
Prior to its sudden death in 2012, Envisat, operated by the European Space Agency (ESA), was the world’s largest civilian Earth observation satellite. The ESA hopes to bring it back home, starting with a scaled-down harpoon expedition known as the RemoveDEBRIS Mission. The RemoveDEBRIS demo satellite will bring its own debris into space, then attempt to catch it. This experiment will also test a net-based system.