Out in the blackness of space two astronauts are repairing the Hubble telescope and enjoying glimpses of their blue planet in the distance. At the same time, Russia decides to test an anti-satellite missile. Within minutes, the debris shower takes out the space shuttle and damages the International and Chinese space stations. Will the astronauts survive?
Many readers will recognise the plot of the movie Gravity. Fewer may know that on 10 February 2009, a real space nightmare came true. A satellite belonging to Iridium Communications relaying data to and from mobile phone users was passing over Siberia’s Taymyr Peninsula. At 16.56 GMT Iridium 33 was there; at 16.57 it was not.
It had collided with a dead Russian military communications satellite. Weighing one tonne and travelling at a relative speed of 12 kilometres per second, the Kosmos 2251 satellite hit Iridium 33 with three times the kinetic energy of an Airbus A380. Both spacecraft disintegrated, scattering wreckage far and wide.
The loss of one of its 66 satellites was a blow to Iridium, but what caused sleepless nights for satellite operators and space agencies everywhere was the floating debris. The US Space Surveillance Network catalogued more than 2,000 fragments bigger than a grapefruit from the collision and a much greater number of smaller ones. At the speeds required for low-Earth orbit, an object the size of a marble can cripple a satellite or punch a hole in a space station.
The Iridium-Kosmos crash did not cause the kind of devastation depicted in Gravity. But there was a tense moment or two: the International Space Station had to make an evasive manoeuvre to avoid a piece of Iridium-Kosmos debris as did other satellites. Around the globe, space agencies suddenly woke up to the threat posed by the thousands of tonnes of objects – operational and dead – cruising in low orbit.
For Donald Kessler it was a Cassandra moment. He’d been predicting a catastrophe of this kind for more than 30 years. A former head of NASA’s orbital debris program, he foresaw that if we continued to launch satellites and leave their paraphernalia floating in orbit, collisions would be inevitable.
Each could produce a debris shower capable of crippling other satellites in a chain reaction – a scenario that came to be known as the Kessler syndrome. If nothing is done our planet could end up ringed with a deadly debris belt spelling the end of the satellite age.
No one yet knows how to snare a piece of tumbling space hardware
and drag it towards re-entry.
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