Growing Concern over the Threat of Space Debris

Like other space faring nations, India too is deeply concerned and disturbed over the possibility of space debris posing a threat to its multi-million dollar satellite missions. For Indian space programme has a crowded schedule ahead with a number of satellite missions lined up for launch in the near future. Not surprisingly then, the Indian Parliament was recently informed that Indian Space Research Organisation(ISRO) is carrying out special analysis to obviate the possibility of space debris colliding with its space missions. Giving details, Jitendra Singh, Minister of State in Prime Minister’s Office informed that “ISRO performs space objects proximity analysis for its operational low orbit spacecraft on a regular basis to assess the collision risk and determine risk mitigation strategies.” Singh also revealed that ISRO has been undertaking mitigation measures like passivation of spent upper stages of launch vehicles and deorbiting of non functional satellites to obviate the possibility of creating space debris. ISRO, which is a member of the Inter Agency Space Debris Coordination Committee (IADC) is contributing to the global efforts to counteract the space debris threat to space missions. The major objective of IADC is to exchange information on space debris research activities between member space agencies to facilities opportunities in space debris research and identify debris mitigation options.

Clearly and apparently, the fast growing belt of space debris around the near earth orbit is the fall out of the growing space activities in the wake of an increasing number of countries joining the race to own satellites systems for wide ranging applications. Indeed, following the orbiting Soviet Sputnik in 1957, there has been a phenomenal growth in launch activities, resulting in the littering of near earth orbit with space debris. Of the 6,700 satellites launched since the dawn of space age, only around 1000 are now active thereby implying that many of the satellites which are dead did contribute to the space debris junkyard. In the rapidly piling up space junkyard, there are fragments of satellites and  launch vehicles, nuts, bolts, electronics devices as well as cameras, screw drivers, food cans and oxygen cylinders left behind by astronauts. And there is no denying the point that the rapidly accumulating density of space debris could render outer space un-navigable and unusable in the years ahead. There are many instances of many multi-million dollar satellites going out of commission after being hit by pieces and fragments of dead satellites.

Against this backdrop, sometime back, a top ranking US official associated with space and defence activities of the country, had noted that there has been a massive spike in the volume of space debris over the last five years on account of  a steady growth in launch activities. Incidentally, the Chinese anti satellite test carried out in early 2007 along with a 2009 collision between a defunct Russian defence spacecraft and a communications satellite belonging to an American satellite operator have been responsible for  a large portion of the space debris now being tracked.

According to one estimate, more than 500,000 pieces of debris or space junk are being tracked routinely as they keep orbiting the earth. Significantly, they all move at speeds upto 17,500 kmph considered fast enough for a relatively small piece of orbital debris to damage an active satellite. There are also countless smaller objects that are difficult to track. In this context, a study by National Research Council(NRC) of USA states that chances that all the  space litter will interfere with satellites or International Space Station (ISS) which dodges the pieces of debris with increasing frequency, are getting higher. Russia’s failed Mars probe Phobos Grunt that went haywire and disintegrated in early 2012 and an American upper atmospheric research satellite that became defunct and plunged into Pacific Ocean in Sept 2011 have also contributed to the growing body of space junkyard. As space scientist point out, pieces of space junk moving at a velocity of upto 8-km per second can easily damage an operational satellite.

On its part, NRC has been pressing ahead with a case for the space agencies to devise innovative strategies for mitigating the threat of space debris. Indeed space researchers are exploring various options centring round the deployment of giant nets, magnets and over sized umbrellas to clear up the mess in earth’s orbit. Significantly, scientists at Federal Institute of Technology at Lausanne in Switzerland have covered “some ground” in designing a novel device named Clear Space One, a sort of vacuum cleaner in the sky. It will be in a position to move close to the dead satellite and grab it with big claw. This would be followed by both making a fiery downward plunge to a certain death. Yet another solution is the so called Electro Dynamic Debris Eliminator (EDDE) which would generate power sufficient enough to move through the magnetic field of the earth and eject out a disposable net to grab the freely roaming space junk. According to a spokesman of Star Technology which is developing EDDE, a fleet of EDDEs could easily clear the near earth orbit of its space junkyard.

Many pieces of satellites and launch vehicles continue to stay in orbit indefinitely if they attain what is called the first cosmic speed. Only objects that slip below an altitude of 120-150 kms re-enter the atmosphere to blaze down as unidentifiable pieces on earth. The collision hazard posed by the space debris is mainly due to the high energy impact caused by its rapid acceleration. Significantly, the first confirmed collision between two catalogued objects took place in July 1996 when a vital device of the French defence satellite Cerise was damaged by a fragment from the European Ariane vehicle. 

In 2013, it was reported that a piece of debris from the Chinese anti satellite test collided with a Russian satellite and rendered it unfit for use. Incidentally, this collision changed the orientation and orbit of the Russian spacecraft designed for scientific experiments. “The current space environment is growing increasingly hazardous to spacecraft and astronauts,” points out Donald Kessler, a former head of the orbital debris programme office of National Aeronautics and Space Administration (NASA) of USA. Meanwhile, NASA is looking at the possibility of clearing space junk with an innovative technological system developed by the University of Michigan. This new system named SpaDE (Space Debris Elimination) seeks to clear the near earth orbit of its space debris by firing focused pulses of gas that will push the debris into a downward spiral where atmospheric heat will destroy them into smithereens

In the ultimate analysis, there is a need for a coordinated global strategy to step up efforts towards mitigating the threat of space debris with a particular reference to research and development. The thrust should be on engineering systems and techniques to obviate the problem of space debris to make heavens safe for space missions including satellite systems, scientific probes, space stations and manned flights.