To date there have been dozens if not more concepts revealed regarding the cleaning of space debris and by various countries including the ESA. The ESA has been very ‘space debris conscious’ as is evidenced by the numerous technologies they have explored in this arena. Take for example back in July 2012 the use of capturing debris with throw nets., or the clamping concept, an ion beam for no contact maneuvering, the Active Debris removal which used expanding foam, and many others. (For more detail:http://www.esa.int/gsp/ACT/doc/MAD/pub/ACT-RPR-MAD-2013-04-KW-CleanSpace-ADR.pdf)
NOW the ESA has set its sights on harpooning space debris as part of their Clean Space Initiative. Granted to date countries have all recognized the need and even floated ideas, but the ESA intends to launch their e.DeOrbit mission in 2021. The ESA plans to examine the potential for the mission to use space harpoons to capture large items, such as renegade satellites and the upper stages of rockets. What is the mission at present? The mission is to clean up the polar orbits from an altitude of 800 to 1000 kilometers.
Actually this is perfect. We could divide the many orbits and altitudes up among the space faring nations. Each would be responsible for cleaning just their portion of the sky. Let’s see; approximately 5000 to 700,000 pieces of sizable space debris (not the screws and nuts or bolts). Of space faring nations there are hmmm…Russia, USA, ESA is many countries so we’ll take that into account (From Austria, Beligium, the Czech Republic and Demark, to Finland, France, Germany, and Greece; also Ireland and Italy, Norway, Portugal, Romania, Spain, and Sweden as well as the United Kingdom, Canada, and several others.) China, Japan, Union of South China and Taiwan, Republic of Vietnam, Federative Republic of Brazil, Mexico, and India.
But I digress. This current plan is a tethered harpoon it would pierce the debris with a high-energy impact and then reeling it in.
The debris that the ESA is targeting is those uncontrolled multi-ton objects that will fragment when colliding with other objects, resulting in debris clouds that would steadily increase in density due to the Kessler syndrome.
Below is a picture of the harpoon and its many sections. The sections of the preliminary design are; a penetrating tip, crushable cartridge to help embed it in the target satellite structure and barbs to keep it sticking in so the satellite can then be reeled in.
The ESA has apparently already done a number of tests, most of which can be accomplished here on the ground. The initial tests involved shooting a prototype harpoon into a satellite-like material to assess its penetration, the strength of the harpoon and tether as the target is reeled in, and the potential for the target to fragment, which would result in more debris that could threaten the e.DeOrbit satellite.
The next step is for the ESA to build and test a prototype of the harpoon and its ejection system in the hope of making it the poster child for the e.DeOrbit mission. This next phase will look at the harpoon impact, target piercing and the reeling in of objects using computer models and experiments, ultimately leading up to a full hardware demonstration.
The European Space Agency has put out a call for bidders to compete for the project contract.
Of course it seems a waste of those billions of dollars of floating trash so perhaps some country will offer a different way where some of the junk gets recycled. I believe I recently heard that the US had a project with that very thing in mind. We’ll see as the time is now before some incident of a catastrophic nature occurs.