We are sending ever more stuff into space, and now megaconstellations of satellites risk causing light pollution on Earth and disastrous debris in orbit – but it’s not too late to save our skies
ON 11 July 1979, shards of a space station fell to Earth. Skylab, the first US outpost in space, was supposed to plunge into the ocean 1300 kilometres off South Africa, but it took longer to disintegrate than predicted.
The 77-tonne behemoth overshot its target and exploded 16 kilometres above the Indian Ocean, sending debris into the water and across a 150-kilometre stretch of Western Australia. Thankfully, nobody was injured. But the incident served as a stark reminder that what we launch into space doesn’t simply disappear.
Today, there are thousands of satellites in orbit, and the number is growing fast. The concern isn’t only that one of these will land on someone’s head. Certainly, our rush to fill space above Earth has significantly upped the odds of cataclysmic collisions in orbit that might rain stuff down on us. But space debris – defunct satellites, bits of rockets and fragments scattered by crashes – is only half of the problem. Satellites are unintentional mirrors, reflecting sunlight and obscuring our view of the stars. They are even making it harder to see threats coming our planet’s way from outer space.
Many insist that when it comes to such problems, we are approaching a tipping point. “If something doesn’t happen, we stand to lose the skies in three years,” says Aparna Venkatesan, a cosmologist at the University of San Francisco, California. “The skies will change forever.”
The pressure is on for something to change. There is …