When Russia fired a missile at one of its own satellites on the weekend, the explosion generated many thousands of pieces of shrapnel that are now zooming around in space at breathtaking speeds.
It added to a sizeable volume of debris already in space, intensifying concerns over the risk that rubbish poses to the International Space Station (ISS) and satellites. The danger lies in a possible collision between objects that are hurtling around at 17,000 mph (27,400km/h).
Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, said there were about 4,000 active satellites and since the Russia test, as many as 19,000 pieces of space debris in low Earth orbit. This is the region of space stretching from about 120 miles to 1,200 miles (200km to 2,000km) above Earth.
He said the test would have generated other pieces of shrapnel, too small to show up on radar, that could number in the hundreds of thousands. All up, the explosion probably increased the number of debris objects by around 10%.
“It’s not a huge increase, but it’s worrying. We have a problem with space junk. So don’t deliberately create more,” he said.
The concern is that flying debris may collide with the ISS or a satellite, with the latter helping with a range of things from internet relay to weather services, imaging, studying climate change and spying. At the speed the debris travels, McDowell said it would “pulverise instantly a satellite and completely destroy it”.
In the worst-case scenario, there could be so many collisions that low Earth orbit becomes too cluttered with debris for satellites to operate. McDowell said while this is a “danger”, it’s not something that would happen immediately.
“It’s like most environmental problems, it’s not like the oceans are wonderfully clear and then one day they are full of plastic. Things get slowly worse and worse.”
The astrophysicist said the number of near-misses in space is rising, and the number of collisions – while still rare – is also rising. In March, a piece of Russian debris hit a Chinese satellite, generating a spray of fresh junk. Tracking debris can help avoid mishaps but ultimately, some of it will need to be removed.
Some progress has been made on this in recent years. McDowell said many involved in space are operating in a “cleaner” way and there are processes that naturally reduce some of the debris. But all of that is wiped out in a day with a collision like the Russia test.
“At some point we’re going to have to have space garbage trucks that go up and take some of this stuff,” he said. “That’s going to be expensive. The technology is just about there now, the money is not. But I think it has to come.”
Adding to his concerns is a steep ramp-up in commercial activity in space which McDowell said had begun to dominate government activity in recent years. Many thousands of new satellites have been launched and up to 100,000 could be added in the next few years.
“There’s a real concern that we’re getting a real environmental problem in outer space. Commercial activity isn’t being regulated adequately … it’s happening faster than regulation,” he said.
“It’s largely US and Europeans but even China now is starting to have a true commercial space sector. It’s a bit of a wild west out there.”