Tonight, a dead Soviet satellite and a discarded Chinese rocket body will fly toward each other, reaching as close as 12 meters (39 feet) apart, and have a high chance of crashing somewhere above the South Atlantic Ocean.
According to satellite and space debris-tracking company LeoLabs, there’s a 10 percent chance that the two dead spacecrafts would collide at 8:56 p.m. ET. It may not sound like a great risk, but it’s significant in aerospace terms. (NASA will move the International Space Station if its chance of smashing into another object is greater than 0.001 percent.)
“This event continues to be very high risk and will likely stay this way through the time of closest approach,” LeoLabs tweeted late Tuesday.
The two large pieces of space junk are currently orbiting around Earth at an altitude of around 615 miles. At that height, a collision won’t pose a danger to anyone on Earth. But if it happens, the explosion would send thousands of smaller pieces of debris in all directions, increasing the risk of future collisions in space.
“It’s maybe a much bigger problem than a lot of people realize,” LeoLabs CEO Dan Ceperley told Business Insider. “If this turns into a collision, it’s probably thousands to tens of thousands of new pieces of debris that is going to cause a headache for any satellite that’s going out into upper low-Earth orbit, or even beyond.”
The Soviet spacecraft in question is a retired navigation satellite called Parus (Kosmos- 2004) launched in 1989. It’s about 17 meters (56 feet) tall and 2 meters (6 feet) in diameter and weighs 800 kilograms (1,760 pounds). The Chinese rocket body is a CZ-4C third stage measuring about 7.5 meters (25 feet) long and 2.9 meters (9.5 feet) in diameter.
Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, tweeted images of the two spacecraft when they were both functioning.
Space debris is a growing concern for scientists and commercial players. Per the European Space Agency’s latest count, there are more than 34,000 objects larger than 10 cm in diameter moving in high speed in Earth’s orbit. Those include thousands of operating and defunct satellites, spaceship, and discarded parts from other missions.
And busy satellite missions, particularly SpaceX’s Starlink, are making Earth’s orbit even more crowded.
Last week, rocket launch startup Rocket Lab’s CEO Peter Beck told CNN that the sheer number of objects in space right now has made it difficult and dangerous to launch space missions. He said the company recently had to pick half a dozen separate launch windows to find a clear path without colliding with any Starlink satellites.