ESA Resorts to Harpooning Threatening Space Debris

In an effort to secure and eliminate potentially threatening space debris orbiting around Earth, the European Space Agency (ESA) is considering resorting to harpooning these tumbling satellites, according to their press release.

When we think of harpooning we usually think of spearing fish like in the Stone Age, but this concept, which has already undergone initial investigations by Airbus Defence and Space in Stevenage, UK, might prove more effective.

Decades of launches have left Earth with a trail of junk floating around it - about 17,000 objects, some bigger than a coffee cup or smaller than a one centimeter nut. While seemingly miniscule, this debris threatens to collide with present and future space missions.

NASA estimates that this junk travels at speeds of 17,500 mph.

The only way to prevent the debris cloud from moving into crucial lower orbits - where satellites are, for instance - is to remove large items such as old, broken-down satellites and rocket upper stages. ESA officials see these uncontrolled objects as bombs, set to collide with another celestial object at any moment. That is, if they don't already explode due to leftover fuel or partially charged batteries heated up by sunlight.

Not only could the resulting debris cloud make crucial orbits hazardous, but it could cause subsequent collisions in a chain reaction. Lawmakers announced last month that they expect a real-life "Gravity" (the Hollywood hit film) to occur if the space debris problem is not dealt with.

ESA's Clean Space initiative is working on the e.DeOrbit mission for flight in 2021. With sophisticated sensors and autonomous control, it could potentially track, hone in on and reel in several tons of orbiting junk.

The harpoon concept may pose some challenges, but ESA plans to build and test a prototype "breadboard" version in the hope of adopting the harpoon and its ejection mechanism for the 2021 mission.