Sometime this weekend, a massive boost from a Chinese rocket will begin an uncontrolled fall back to Earth from space, and due to its considerable size and weight, some parts may survive the descent through our planet’s atmosphere and hit the ground. The chances of the rocket hitting and killing someone are extremely rare, but a similar Chinese rocket crash last year caused widespread concern around the world, which means this rocket will likely do the same.
The booster is part of a Long March 5B rocket, which launched on July 24, sending a new module into orbit for China’s growing Tiangong space station. After the giant rocket reaches space, it sheds a rather massive part of itself: its core booster. This booster remains in orbit, tethering the planet before falling back to Earth. Since the rocket part is more than 100 feet long and weighs more than 22 tons, it is possible that up to 9 tons of material could survive the fall.
Space trackers are doing their best to predict exactly when and where the Long March 5B reinforcement will drop. The situation looks very similar to last year’s global scare over an uncontrolled Chinese rocket falling back to Earth, as well as a similar uncontrolled re-entry in 2020. Both cases also involved a central strengthening of the China’s Long March 5B, which lacks the ability to dispose of itself in a controlled manner. Fortunately, last year the rocket fell into the sparsely populated Indian Ocean, but in 2020, the falling rocket dumped debris off the Ivory Coast, sending metal pipes and other objects into villages without causing any injured
“This is not necessary. We have the technology to not have this problem.”
Still, the risk to the average human from this year’s rocket is so low that it shouldn’t keep anyone awake at night. In fact, for any person on Earth, there is a six in 10 trillion chance that part of that rocket will hit you and cause you some kind of casualty or injury, according to the Aerospace Corporation, a non-profit organization that does space research and development. as well as providing technical guidance on spaceflight. But the fact that space trackers have to keep dealing with these kinds of problems without knowing when and where the rocket will land is frustrating.
“Why are we worried? Well, it caused property damage last time, and people need to prepare as a result,” said Ted Muelhaupt, a space traffic expert and consultant in the Office of Corporate Chief Engineering, Aerospace Corporations , during a press conference about the rocket. “Besides, this is not necessary. We have the technology to not have this problem.”
Reports of a 12m long object crashing into the village of Mahounou in Ivory Coast. It is located directly on the CZ-5B re-entry track, 2100 km away from the space track re-entry location. Part of the stage may have cut through the atmosphere so far (photo: Aminata24) pic.twitter.com/yMuyMFLfsv
— Jonathan McDowell (@planet4589) May 12, 2020
In the United States and Europe, the rule for space operators is that if there is going to be any sort of uncontrolled reentry of space debris into Earth’s atmosphere, there must be less than a 1 in 10,000 chance that the falling object will cause any type victim or injured on the ground. That’s a particularly high bar to clear, and that’s why US and European missions have to be careful how the rockets they send into space are disposed of. “Basically, once you’ve delivered your payload, you turn the rocket around, fire up the engine, and drive it back into the ocean somewhere, usually an unpopulated place,” Marlon Sorge, debris expert spatial and technical. the Aerospace Corporation, he said. “Do that and you’ve pretty much mitigated the risk right there.”
Controlled removal is something that most release providers around the world already do. SpaceX and the United Launch Alliance, for example, intentionally deposit parts of their rockets on the ocean after launching into space. Also, the core of SpaceX’s Falcon 9 rocket is famous for returning to Earth and landing vertically, either on a drone ship or a landing pad, following its flights. The base Long March 5B booster does not have this ability. Once launched into orbit, the engines in the rocket core cannot be re-ignited. “They’re designed for a single burn,” Jonathan McDowell, an astrophysicist at the Harvard Center for Astrophysics and an expert in space tracking, tells The Verge. “And so this thing only burns once and then it goes out, and it’s dead.” Then we just have to wait for it to fall back to Earth as its orbit decays over time.
“This thing only burns once and then it goes out, and it’s dead.”
The Aerospace Corporation estimates that there is a 1 in 1,000 to 1 in 230 risk of a casualty from the crash of the Long March 5B booster. This is 10 times higher than the 1 in 10,000 threshold, which is why there is greater vigilance around this particular case. And whenever China pulls a stunt like this, the US is not particularly happy about it. “Space nations must minimize risks to people and property on Earth from re-entries of space objects and maximize transparency regarding these operations,” NASA Administrator Bill Nelson said when the Long March 5B of 2021. “It is clear that China is not meeting responsible standards for its space debris.”
China seems to have taken note of the criticism. During this most recent launch, a Chinese official during CGTN’s launch live stream mentioned that they had made improvements to remove the boost after launch. “The last segment, or the middle segment, once [enters] in orbit, too [works] as a spacecraft,” Xu Yansong, former director of international cooperation at the China National Space Administration, said during the live broadcast. “So we will have to bring it in safely and in a controlled manner. So one of the first missions couldn’t do it, but later, we improve our technologies. And so what we call the last stage passivation has been carried out so that we can safely return the last fuselage.”
Our latest prediction for the re-entry of the #CZ5B rocket body is: 31 Jul 2022 00:24 UTC ± 16 hours Re-entry will be via one of the ground paths shown here. It is still too early to determine a significant debris footprint. Follow this page for updates: pic.twitter.com/CZRQBClOAg
— The Aerospace Corporation (@AerospaceCorp) July 28, 2022
However, nothing seems to have changed since the last scare. In fact, the European Union’s Space Surveillance and Tracking Network has discovered that the propellant is falling through space, indicating that there is no control over the object. So we’re going to go through the whole process of predicting where it’s going to go down again. As of now, the best guesses from the European Union, the US Space Force and the Aerospace Corporation as to when it will go down are Saturday night or Sunday morning. As for where it will land, it will be between 41.5 degrees north and 41.5 degrees south. That means about a billion living north and south of those lines are at zero risk. (Boston and parts of Tasmania: congratulations, you’re out of the zone.) But 88 percent of the human population lives within that range, according to the Aerospace Corporation.
“You’re 80,000 times more likely to be struck by lightning than you are by space debris.”
Predictions will become more accurate with each passing day as we get closer to Sunday, and the Aerospace Corporation continually updates its predictions here. The European Union is also following up, as is the Space Force. As for what to expect when the rocket falls? According to past experience, debris could spread over an area hundreds of miles long along the rocket’s orbital track. Some pieces, depending on their size and weight, can hit the ground slowly, while others can hit the ground quickly, at speeds that can reach hundreds of miles per hour. Ultimately, it’s a guessing game, and we may not know much about this event until the rocket crashes. “The story of things coming back in has been a story of continuous surprise,” says McDowell. “How many actually survive re-entry? Sometimes they survived more than you might have initially expected.”
But while there’s a little more risk than usual with this falling rocket, it’s important to keep things in perspective. “The risk for any given individual in a given year of being stuck in the head by a piece of space debris is one in 100 billion,” Muelhaupt said. “You’re 80,000 times more likely to be struck by lightning than by space debris. But that doesn’t mean it’s a good thing to do.”
So enjoy this new round of falling rocket uncertainty. Once it’s over, we’ll probably have to do it all over again. Another Long March 5B release is tentatively scheduled for this fall.