NASA says there are half a million pieces of space debris. Out of them, over 20,000 are larger than apple. Most of them are travelling at a speed of around 7 kilometers per second.

The above mentioned speed is enough even for a cherry-sized piece of metal to create a disastrous effect, believes the deputy head of ESA Space Debris Office, Holger Krag. The European Space Agency (ESA) now plans to solve the problem of space debris.

The ESA plans to launch the e. DeOrbit mission, in 2021, as a part of its Clean Space Initiative. Main aim of the mission will be to make the important polar orbits between altitudes of 800 and 1,000 km to be free of space debris.

Now, the ESA has announced that it is thinking to assess the potential for the mission to use space harpoons to catch hold of bigger items like derelict satellites. Earlier, the ESA has announced of looking out for ways to capture and secure space debris.

Some of the approaches considered by the ESA are, keeping the debris in a net, grabbing the debris using robotic arms and another option is to use a tethered harpoon. The last option would destroy the debris into pieces with a high-energy impact.

This approach can be used for bigger-sized debris, but not for smaller debris. Airbus Defense and Space in Stevenage, UK, are already carrying out investigations on the space harpoon concept. The design under investigation includes a penetrating tip, crushable cartridge to help embed it in satellite structure and barbs to keep it in the place.

Initial tests have also been carried out and the ESA will follow up these tests by building and testing a prototype `breadboard' version of harpoon thinking that it can be used for the e. DeOrbit mission.