This Friday, an object that scientists have been carefully tracking for some time now, dubbed WT1190F, will enter the earth's atmosphere in the skies above the Indian Ocean. Given its size and unusual orbit, scientists believe it's an old piece of space junk, perhaps even a spent rocket or a panel from one of the Apollo spacecraft. WT1190F is not alone up there. It turns out that space is a veritable junkyard.
The whole mess got started in October 1957, when the Russians launched a little ball of metal called Sputnik into space that proved – yes – you can put an object into orbit around the Earth. And then, as is so often the case once the impossible is shown to be possible, it quickly became routine.
As we speak (well, as I write and you read), a few thousands operational satellites are zipping around in the skies above us taking pictures, gathering data, and making your GPS work.
"Most satellites are either in what we call LEO – low Earth orbit, which is just a few hundred miles up or GEO – geostationary orbit – where the television satellites are, and that’s 23,000 miles up," explained Harvard University astrophysicist Jonathan McDowell.
But according to McDowell those satellites are just a small fraction of the objects circling the Earth at some 18,000 miles per hour (5 miles a second!). The vast majority of it? It’s junk.
"It turns out, we accidentally launched a whole bunch of time bombs into orbit," said McDowell.
For years, the rockets used to launch satellites would – by design – carry a little more fuel than was needed – just in case. Those spent rockets also ended up in orbit and would degrade over time.
"Suddenly the fuel and the oxidizer get together and have a party and the next time you see this object it’s 200 little pieces," explained McDowell.
Then there have been the various successful anti-satellite weapons tests by the Soviet Union and the United States. In 2007, China even got in on the act.
"So there’s like 2,000 pieces of debris being tracked right now from this one Chinese anti-satellite event," said McDowell.
And in the increasingly congested LEO and GEO superhighways above earth, there is an ever-increasing risk of accidents. Case in point: High above the North Pole in 2009, when a working commercial communications satellite ran into a dead Soviet communications satellite, breaking both up into thousands of little pieces.
You can see the problem here.
McDowell says many of the objects closest to earth work their way back down within a decade, but the stuff out in geostationary orbit? That can stay out there for millennia. All told, the Department of Defense and NASA constantly track some half-a-million pieces of space debris, 20,000 of which are larger than a softball. It's imperative that they do. At the speed this junk is moving, even a fleck of paint can cause serious damage.
"In the later space shuttle launches for example they had a number of holds in the countdown to wait for space debris to pass, explained McDowell. "A couple times a year now the space station has to dodge."
It’s an issue McDowell says space agencies, militaries, and the private sector are beginning to take seriously. But there is one small wrinkle. We don’t really know how to clean it up.
Alvar Saenz Otero, director of the MIT Space Systems Laboratory, is working on that. He says the main problem is that not only are these objects in orbit, they are also spinning unpredictably. In his words, "a well-thrown football is spinning perfectly and it’s very easy to catch. A wobbling football is very hard to catch."
For almost a decade, Otero and his team have been refining a system that would enable a spacecraft to match the spin of a piece of space junk, capture it, and haul it out of orbit. In Otero’s opinion, figuring this out is a must.
"If we wanted to do nothing else in space right now, we’re good. We have to be careful. But the challenge is we want to do a lot more in space," he said.
That includes next generation satellite arrays that could allow us to measure pollution in detail – in real time, and bring WiFi to literally the entire planet. And while McDowell says this week’s arrival of WT1190F won’t help us resolve the space junk issue, it will help us get closer to understanding another – potentially catastrophic – matter.
"It’s a great dress rehearsal for an asteroid impact," he said.
And not the fabled big one, like the one that likely wiped out the dinosaurs some 60 million years ago or – more recently – took out Bruce Willis in the film Armageddon.
"Much more likely, you’ll get a city buster one or even one that could take out part of a city," said McDowell.
We got a taste of just how powerful a even the “small one” can be in 2013 when an asteroid exploded in the skies over Chelyabinsk, Russia back in 2013 with 20-30 times the force of an atomic bomb.
"This kind of catching something when it’s still a few weeks out, organizing for observations, getting additional observations to refine its orbit, all of that is super useful practice for the day when that happens," said McDowell.
McDowell says there’s little threat to us here on the ground on Friday, as scientists expect most if not all of WT1190F to burn up in the upper atmosphere as it hurtles toward the Indian Ocean.
"But at the same time if I were in a boat, east of Sri Lanka that morning I would put my tin foil hat on," he quipped.
If you're reading this out there in the Indian Ocean, please remember to recycle that tin foil hat when you’re done. The last thing we need is more junk.