Space agencies are taking seriously problem of space debris. First active mission under ESA Cleanspace program is scheduled on 2021.
Space debris was recognized as a problem at the very beginning of the Space Race. When first Soviet satellite was launched in 1957, North American Aerospace Defense Command (NORAD) started to compile Space Object Catalog – database of all objects launched from Earth and whom reached the space. Database is still developing, but after first tests of anti-satellite weapon (ASAT) during early sixties, another problem existed. Due the explosions of destroyed satellites many small pieces (from metal objects to leaf of paint) are on the orbit and moving with high speed. These objects, in spite of their small dimensions, were able to destroy or damage spacecraft or satellite. John Gabbard, NORAD employee, started another database this time devoted to products of explosions. He also created special technique for calculating orbit of the remains of the destroyed object. Since early eighties, American space industry started to incorporate technologies helping in reducing space debris. In spite of this, with increasing launches around the world, amount of space trashes was growing faster than they were burning in atmosphere. Numbers will show scale of the problem: in 1981 number of objects qualified as space debris, was estimated for 5000. In 2005 this number increased to 13000. According to University of Southampton researcher Hugh Lewis (given to public on European Air and Space Conference in 2009), in next ten years possibility of collision with space debris will increase for 50%. In 2011 NASA announced about tracking 22000 space debris objects.
It should not be surprising that problem of space debris was under consideration by ESA for a longer period of time. It gave an effect in Cleanspace program. Main objective was determined as long term research on results of space exploration for both Earth and space environments. Under Cleanspace program, first spacecraft designed for cleaning orbit was designed. Called e.Deorbit, with launch scheduled on 2021, will be put into polar orbit with Vega rocket. After successful reaching orbit, it will search for inoperative satellite. Using mechanical tentacles and robotic arms (or deployable net – it is still considered) it will catch object and change the orbit. Catch object will burn with e.Deorbit in the atmosphere. Another solution was invented by Busek Co. Inc. – Orbital Debris Remover (ORDER). It will be small spacecraft which catches debris, attach smaller satellite to it. Attached satellite will move debris into desired place. ORDER will be launched with 40 sub satellites and necessary fuel onboard. Another idea given by NASA was laser boom. It was planned that laser emitter on Earth would illuminate debris and using ablation process on the front of debris. Ablation will work as thruster and will change debris orbit. Main drawback of this solution is possibility that illuminated debris will break into many pieces before changing direction. Another concept was announced by Star Inc. on 7 January 2010 as future research project contracted by NASA. Called ElectroDynamic Debris Eliminator (EDDE) will be a spacecraft designed to catch debris parts. Still NASA considers all these projects as uneconomical. Cost of removing one part of debris is equal to one new spacecraft.
Most recent programs against space debris are Space Sweeper with Sling-Sat (4S) and Space Net. Space Sweeper was designed on Texas A&M Aerospace by Engineering Professor Daniele Mortari and his Ph.D. student Jonathan Missel. It is designed not to attach to debris and burn with it in atmosphere. It will get close to debris, catch it in its special grasper (resembled a half sphere), make a spin around its axis and shoot debris, just like from old type slingshot, to atmosphere. This procedure will save fuel and allow extending mission time, because momentum after spin will be utilized for moving to another object. Another idea is created by JAXA and gives possibility for removing space debris in more comprehensive way. It is called Space Tethered Autonomous Robotic Satelite-2 and is basically a 300 m long net (JAXA even brought Nitto Seimo, Company manufacturing fishing nets) build from aluminum and steel hanging from unmanned spacecraft. Spacecraft’s onboard sensors are looking for light reflections from debris and align spacecraft automatically. Debris is catch in magnetized net. When net will become full, spacecraft will change orbit and burn with net full of debris in atmosphere. Jaxa is considering building 10 km net to catch satellites and other large objects. STARS was launched on atop of H-IIA on February 2014. It was tested for general operations, maneuvering, deploying and magnetizing net. No debris was catch.
Space debris is important problem, especially in the moment of intensification of space exploration and increasing number of planned commercial manned missions. Luckily, still there was no tragic disaster, like showed in the “Gravity” movie. But accidents were noticed; for example during MIR space station operating: space debris destroyed or breaks solar panels many times. International Space Station is forced to maneuvering to avoid space debris periodically. Serious accident took place in 2009 when Iridium 33 satellite crashed with not working Kosmos-2251 satellite 789 km over Siberia. Both satellites crashed with speed at 42120 km/h. How many old satellites are still in space shows fact that American satellite Vanguard-1, launched in 1958, will remain on orbit for next 240 years.