A dead Soviet satellite and an old rocket booster could collide in space tonight

Space traffic experts are tracking two pieces of orbital garbage that appear to be careening toward each other: A defunct Soviet satellite and a discarded Chinese rocket booster that are expected to nearly miss each other — with a slight chance of colliding — Thursday evening.

No one knows for sure if the objects will collide, and near-misses happen in space all the time. But LeoLabs, a California-based startup that uses ground-based radars to track spaceborne objects, is putting the odds of collision at 10% or more. That’s high, but not uncommon LeoLabs CEO Daniel Ceperley told CNN Business on Thursday.

“Multiple times a week we’re seeing dead satellites come within 100 meters of each other, moving at tremendous speeds,” Ceperley said. The company decided to raise public awareness about this particular event, he said, because the two objects are both large — and likely to create an enormous debris field if they collide — and because they’re in an area of orbit that’s still relatively clean compared to nearby orbits. The company is also trying to raise more general public awareness about the debris problem, he said.

The Soviet satellite, which launched to space in 1989 and was used for navigation, weighs nearly 2,000 pounds and is 55 feet long, according to Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics. And the rocket booster, part of a Chinese Long March launch vehicle that likely launched in 2009, is about 20 feet long. Neither of the objects is still in use.

Moriba Jah, an astrodynamicist at the University of Texas at Austin, has long been trying to do the same thing. His data, which shows dozens of potential collisions happening at any given moment, shows that the Soviet satellite and discarded rocket booster are expected to come within 72 meters of each other this evening, with a risk of colliding. Though, he couldn’t say for sure whether a collision is “likely.”

If the rocket and satellite do collide, it would be the first time in more than a decade that two objects spontaneously collided in space — a situation space traffic experts have hoped desperately to avoid.

The last collision, in 2009, saw a dead Russian military satellite ram into an active communications satellite operated by US-based telecommunications firm Iridium. That event produced a massive cloud of debris, most of which is too small to track from the ground. And the wreckage is still in orbit, posing a constant threat to nearby satellites.

There are also already hundreds of thousands — possibly millions — of objects whirling around in orbit uncontrolled, including spent rocket boosters, dead satellites and detritus from military anti-satellite missile demonstrations. The junk is heavily concentrated in areas of orbit closest to the Earth’s surface. And, though it doesn’t pose much of a risk to humans on the ground, it does threaten hoards of active satellites that provide all sorts of services, including tracking the weather, studying the Earth’s climate, and providing telecom services. The debris also threatens the International Space Station, where crews of astronauts have lived since 2000, and which has had to adjust its own orbit three times this year already due to space debris.

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McDowell explained on Twitter, a new collision would be “very bad.” It could lead to a 10% to 20% increase in the amount of debris in space, and each new piece of debris boosts the odds that more collisions will keep happening.

It could even set off a disastrous chain reaction, leaving space littered with an impenetrable field of garbage that brings new rocket launches and space exploration to a grinding halt.

Part of the problem is that outer space remains largely unregulated. The last widely agreed-upon international treaty guiding the use of outer space hasn’t been updated in five decades, which has mostly left the space industry to police itself.

The rise in popularity of megaconstellations — epitomized by the Starlink internet constellation that Elon Musk’s SpaceX is building — has sparked a new wave of discussion about the risks of congestion in orbit. Rocket Lab CEO Peter Beck told CNN Business last month that growing congestion in space is already making it more difficult for his company’s rockets to find a clear path to orbit to deliver new satellites.

Complicating the problem: space traffic experts still don’t have a fully accurate map of the objects orbiting earth. Possible collisions are tracked using government and privately owned sensors on the ground that attempt to pinpoint exactly where everything is, but the process involves a lot of guesswork.

Pooling space traffic data into a single database could help space traffic experts develop a far more accurate picture of what’s happening. But companies and governments have been hesitant to cooperate, Jah said.