Removal of Active Man-made Orbital Debris ? A Great Challenge to Space Scientists

After more than fifty five years of space activities, the sky above the Earth being highly polluted with orbital debris, has become the cause of serious concern for safe placement of satellites in the desired orbits as well as in their safe functioning. Orbital or Space debris are the fragmented parts of nonfunctional satellites and used rockets orbiting the Earth at speeds of up to several kilometers per second. Satellites are placed in different orbits for performing different functions, majority of which are at Low Earth Orbit (LEO) up to altitude of 2000 kilometers, some are in Geostationary Earth Orbit (GEO) up to altitude of 36000 kilometers and few are also in High Earth Orbit (HEO). More than 7000 man-made objects launched in various orbits around the Earth since the dawn of space age, about 2/3 rd of these are in LEO. It is estimated that there are now roughly 5 lakh pieces of orbital debris available of which nearly 3.7 lakhs debris present in LEO are of the size between 1 cm to 10 cm while nearly 22000 debris are of the size greater than 10 cm. Due to high impact speed in space, even sub millimeter debris poses risk of collision and severe damaging of the satellite placed already in orbit or to be placed in future. Since the risk of collision is growing super-linearly due to Kessler Syndrome and is of great concern to all satellite operating nations, sincere effort to reduce orbital debris is getting importance. Active removal of existing large objects like non-functional space craft and residues of lunch vehicle from orbit at least five numbers per year can prevent future problems. There are substantial technical, economic, political and legal barriers to develop, deploy and operate active debris removal systems. Hesitation arises due to similarities between space debris removal systems and space weapons. The system which can remove the nonfunctional space object from the orbit can also remove the useful one of others. Efforts are going on to develop different debris capture systems to reduce debris accumulation in almost all orbits, from low to geostationary altitudes. Space scientists have to face a great challenge for smooth running of their space program. All space-faring nations have to reach a Consensus on Active Debris Removal (ADR), Cooperate for removal of debris of space craft of different countries, Collaborate like a single entity to achieve the goal and Contribute in cost sharing for preserving the space for future generation.