As soon as we left the planet, we began leaving rubbish in orbit. Now it is putting space stations and astronauts at risk. What can be done about the millions of pieces of debris?
In November last year, the five astronauts and two cosmonauts on the International Space Station (ISS) were ordered to suit up and take refuge in their capsules for fear their spaceship might be struck by flying debris. Russia had deliberately destroyed one of its own satellites with a missile, producing a cloud of wreckage that threatened the orbiting outpost. “It’s a crazy way to start a mission,” Nasa told its sheltering crew, who had arrived only days beforehand.
The incident revealed how hairy Earth’s orbit has become, and it wasn’t a one-off. Two weeks later, mission controllers received another alert that the ISS might be hit by more debris. This time, Nasa delayed a planned spacewalk amid concerns that the astronauts could be in danger if they went outside. Before the week was out, yet another warning came in, this one forcing the space station to dodge a US rocket body that has been barrelling around Earth since the 90s. It was all worryingly reminiscent of the 2013 movie Gravity, in which debris from a shot-down satellite damages not just the ISS but the Hubble space telescope and a visiting space shuttle.
