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NASA is planning to use a “laser broom” to clean up the cloud of space trash that is currently orbiting around our planet. While the pieces floating around the earth are only fragments and often very small, they than cause a terrible problem for astronauts if they hit the weak points of a space shuttle – just as they are capable of taking out important satellites and break down communication here on earth.
The situation is as following: close to ten million human-made objects are at present time floating around our planet, approximately 800-2.000 kilometers above the surface where commercial and military satellites also move around.
This ‘cloud’ consists of around 20.000 piece of space-junk larger than five centimeters and can be spotted through telescopes from earth. The largest fragments come from space collisions, old satellites and wasted rocket fuel-tanks. Half a million fragments are only more than a centimeter big but they are capable of causing huge damage if they collide with other objects because of the high speeds that occurs when moving in such a low orbit.
For this reason, NASA has just announced the approval of funding for a new project that will test the idea of “sweeping” the space-junk out of the earth’s close orbit by directing relatively weak laser beams at the fragments to change their direction or speed. The goal is to reduce the risk of collisions. “It actually doesn’t sound completely implausible that it will work on smaller object” Peter Davidsen, a system engineer from the Danish company Terma, says to the Danish daily Berlingske Tidende. “The volume of space-junk will continue to grow in the future and at the moment we don’t have many option other than keeping our fingers crossed that it won’t hit anything important.”
Around this time last year, Davidsen was in fact sitting in the control room at Terma, who produce aerospace, defense and security applications, crossing his fingers that a large piece of Russian space-junk would pass by the Danish research satellite ‘Oersted’ – a project he had worked on for 18 years. This was the first time that a Danish project had been warned by the US of a ‘near miss’ in space and the case received a lot of attention at the time. “Since then, we have actually received more warnings like it – usually a couple of them every three months” Davidsen explains.
Other examples have not been so fortunate. In February 2009, the old Russian military satellite Kosmos 2251 collided with a satellite owned by the American company Iridium. To put the damage in perspective, Iridium makes some of the satellite phones that are used to pass on information in and out of Libya at the moment, where ordinary communication systems have been paralyzed.
The NASA “laser broom” is expected to be situated near the poles where most of the trash accumulates. They will be connected with grand telescopes which will guide the laser beams in the sky. The project is not expected to be too expensive since construction takes place on earth and will only use relatively weak lasers which will not require any specialized equipment.
Engineers at the Ames research centre in California, assigned to develop the project, have calculated that the “broom” will be able to sweep enough space-junk aside to significantly decrease the risk of the so-called Kessler syndrome – a domino effect of collisions already predicted back in 1978 which could cause the destruction of virtually all satellites with unimaginable consequences for the earth’s communication systems.
The current way of avoiding this situation has been to install a type of control system in newer satellites. This way, some are able to change course in orbit while eventually, they will fall down to earth after use.