A massive Chinese rocket body is expected to fall to Earth this weekend, but that doesn’t mean you should rush into a bunker.
The doomed piece of space junk is the core stage of the Long March 5B rocket which launched a module to China’s Tiangong Space Station last Sunday (July 24). The latest predictions show that the 25-tonne (22.5 tonnes) booster will touch down on Saturday night (July 30), although there is quite a margin of error in such estimates: plus or minus 16 hours at this point.
Most of the rocket will burn up in the Earth’s atmosphere, but a significant part of it – approx five to nine tons (opens in a new tab) (5.5 to 9.9 tons), according to The Aerospace Corporation’s Center for Orbital Reentry and Debris Studies — will make it all the way down. However, the chance of a chip hitting someone is slim, given how much of the Earth is covered by ocean and sparsely populated land.
Related: The largest spacecraft to fall uncontrolled from space
There’s a “99.5% chance that nothing will happen,” said Ted Muelhaupt, a consultant with The Aerospace Corporation’s Corporate Chief Engineer’s Office, during a discussion about the upcoming Long March 5B crash that the company broadcast live today (Aug. July) on Twitter.
“Personally, if this came down on my head, I would run out with a camera to see it because I think it would be more of a visual [opportunity] than a real risk,” he added.
The surviving parts of Long March 5B will travel several hundred miles per hour when they hit the ground (or water). Such influences will be energetic and destructive, but they will not be catastrophic.
“The worst case scenario in this event is going to be less severe than a single cruise missile attack that we have seen every day in Ukraine warso let’s put that into perspective here,” said astrophysicist and satellite tracker Jonathan McDowell, who is based at the Harvard-Smithsonian Center for Astrophysics, during today’s discussion.
All that said, the upcoming Long March 5B crash is a serious and unfortunate event, McDowell and others stressed, especially because it could have been avoided.
The core stages of most orbital rockets are steered to certain death in the ocean or over unpopulated land shortly after launch, or, in the case of SpaceX’s Falcon 9 and Falcon Heavy vehicles, come down for vertical landings and eventual reuse. However, Long March 5B’s core stage reaches orbit with the payload and remains aloft until it is brought down by atmospheric drag.
The big Chinese rocket now has three launches under its belt, so we’ve already seen two uncontrolled Long March 5B reentries. One of those falls — following the April 2021 mission that lifted Tianhe, the Tiangong space station’s core stage — happened over an empty sea. But the second, in May 2020, scattered some rocket debris over West Africa, some apparently hit the ground in Ivory Coast (opens in a new tab).
As that incident shows, the potential for injury and infrastructure damage is there in any large scale unchecked space debris fall. And the more such incidents occur, the greater the chance that someone will be injured or killed.
“You’re not going to win the lottery tonight, but somebody might, and that’s why this statistic goes up,” Muelhaupt said. “We’re doing more of these, we’re actually putting someone at risk. And there’s no need to. We have the technology, as the old saying goes, to avoid this. We’ve learned our lessons. We can control reentry.”
China has not fully absorbed these lessons, as evidenced by the Long March 5B’s design. But McDowell expressed optimism that the nation will get on board before much longer.
“I see that China is slowly adopting the norms of other countries in space,” he said. “And I think it’s important to remember that they were kind of a latecomer to space activities. And so they’re catching up, and I think they’re catching up to the norms as well.”
Mike Wall is the author of “Out there (opens in a new tab)” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall (opens in a new tab). Follow us on Twitter @Spacedotcom (opens in a new tab) or on Facebook (opens in a new tab).