ORBITAL DEBRIS CAN MAKE A MESS OF THINGS

Our planet is surrounded by junk that poses a threat to astronauts and spacecraft

Debris in space is a well-documented problem; NASA estimates that there are roughly 13,000 objects larger than ten centimetres in diameter floating around in the near-earth environment. The danger from orbital garbage is all too apparent. In 1983, a tiny paint fleck hurtling through space hit Space Shuttle Challenger’s window, causing so much damage that the entire window had to be replaced. The International Space Station

(ISS) regularly manoeuvres out of the path of oncoming junk.

Most of this junk is moving at extremely high speeds – up to seven times the speed of a rifle bullet. At that speed, not only would you not see it coming, but an object no bigger than a penny could also easily destroy an aeroplanesized spacecraft. Although spacecraft are built with shielding to help protect them against this sort of collision, the risk of a major catastrophe is on the increase.

Of even more concern is the prospect of ‘runaway’ disintegration. This is known as the Kessler effect. If a major collision event were to occur in near-earth orbit, it could set off an uncontrollable chain reaction, quickly resulting in large regions of space being awash with dangerous junk. Although the current levels of debris orbiting our planet are unlikely to present a high-level threat, this ‘critical mass’ could be achieved in only a few decades.

hole A tiny chip of paint made this impact window of Space Shuttle Challenger in the This NASA orbital debris plot shows primary debris fields in low-earth orbit, where 70 per cent of all catalogued debris is found. Another debris field can be found farther out in geosynchronous orbit