Even the sky is not the limit for human greed. After the planet Earth, it is now the turn of space to suffer the consequences of human recklessness. Space debris, the junk that humans leave in space, can be extremely dangerous as they zip around the Earth at nearly 10 km per second — almost seven times faster than a bullet — and risk colliding with communication, monitoring and astronomy satellites. The amount of space junk orbiting the Earth has skyrocketed in recent years. It is estimated that more than 30,000 pieces bigger than 10 cm in size litter the low-Earth orbit — up to 2,000 km above the Earth’s surface. ‘Gravity’, the 2013 Hollywood science fiction thriller about astronauts lost in space after orbital debris destroys their space shuttle, was fictional but the threat of a cascade of space debris is very much real. The orbital debris can come from rocket-launching material and defunct satellites or from metal, screws, paint flakes and other smaller items. Even a single paint flake at that speed can damage or destroy a satellite. Explosions in orbit, triggered by residual energy stored in fuel and batteries aboard spacecraft and rockets, are a significant source of debris. Increasing government and private space traffic is pushing up the combined mass and area taken up by space trash. Right now, there are nearly 10,000 satellites orbiting the Earth. The polluted orbital environment is becoming more crowded by the day, threatening the growing space economy.
It’s time for nations to stop treating space as a garbage dump and clean up the Earth’s near orbit. Strange, as it may sound, there is still no international treaty that limits space junk or sets standards for negligence. Global cooperation is needed to arrive at an agreement that outlines responsibilities and imposes fines on companies whose spacecraft debris causes harm. Under the 1967 Outer Space Treaty, nations are supposed to be responsible for damages caused by space junk, even if it was originally launched by a private firm. But, the arrangement has not worked. One way to reduce the risk of future impacts with space litter is to burn up the spent satellites and rockets in the atmosphere. The Indian Space Research Organisation (ISRO) has taken a lead in this area and plans to include the debris-free approach for each mission, beginning 2025. This would include carefully selecting clean orbits, budgeting for fuel to dispose of rockets after the mission and efficiently controlling trajectories as they re-enter the earth’s atmosphere so that they don’t leave any orbital debris. Although commerce might be the bulk source of space debris, the militarisation of Earth’s orbit has had and will continue to play a role in cluttering orbits. Experts have suggested a global treaty along the lines of the Antarctic convention to keep space clean before tensions rise any further.