It is possible that a large Chinese missile object will crash to Earth tomorrow (July 30), but no one knows exactly when or where.
The 25-ton (22.5 metric tons) main stage of the Long March 5B rocket will return to Earth’s atmosphere tomorrow at 2:05 p.m. EDT (1805 GMT), plus or minus five hours, according to the The latest forecasts of researchers at the Aerospace Corporation (Opens in a new tab). The booster spent less than a week in orbit; He. She Wentian raisedthe second unit of the Chinese space station Tiangong, on July 24.
Most of the missile body will burn, but large parts of it will most likely survive in the fire lane 5.5 tons to 9.9 tons (Opens in a new tab) (5 to 9 metric tons), according to the Aerospace Corporation’s Center for Orbital and Debris Reentry Studies.
Based on the course of the core phase, we know that these blocks will fall somewhere between 41 degrees north latitude and 41 degrees south latitude. Europe and most of North Africa appear to be out of the line of fire, based on the latest forecasts. We also know that the “footprint” of the debris will be significant, with some pieces likely to fall hundreds of miles from each other.
But at the moment it is difficult to say much more, given the inaccuracy of the re-entry window. The rocket body is orbiting Earth at 17,000 mph (27,400 km/h), after all, so a one-hour error in the expected return time translates to a 17,000 mile error in the footprint location.
This mystery is not an indictment space junk Researchers and satellite tracking. Predicting this fall of debris is really, really hard.
“The obstacle is that the density of the upper atmosphere varies over time; there is already weather there,” astrophysicist and satellite tracker Jonathan McDowell said during a discussion about the space company’s Long March 5B crash broadcast on Twitter yesterday (July 28). ).
“This makes it impossible to predict exactly at what point the satellite will penetrate enough of the atmosphere to melt, disintegrate and then finally return,” added McDowell, who works at the Harvard-Smithsonian Center for Astrophysics.
And the Long March 5B nucleus does not take a smooth, predictable path through the upper atmosphere, further complicating prediction attempts.
Matthew Schop, senior director of commercial space for California-based tracking company LeoLabs, said during a discussion yesterday. “And since we don’t know exactly how that deteriorates, we can’t model it exactly.”
However, we can make some informed guesses about the fall of the rocket based solely on geography. For example, the core of Long March 5B is more likely to enter above water, because the oceans cover more than 70% of the Earth’s surface. Even a fall to the ground is unlikely to result in injuries or damage to infrastructure, given that most people live in large urban areas separated by many miles of open space.
There is a “99.5% chance that nothing will happen,” said Ted Mullhaupt, a consultant in the chief engineer’s office at The Aerospace Corporation, during yesterday’s discussion.
so there Do not panic. But feel free to get upset that we absolutely need to worry, McDowell, Shoppe and Muelhaupt all emphasized that the coming crash was avoidable.
Other orbital rockets tend not to cause such problems; Its large main stages are directed into the ocean or into uninhabited areas shortly after liftoff, or in the case of SpaceX’s Falcon 9 and Falcon Heavy bombers, descended for vertical landing for future reuse. By contrast, the Long March 5B core reaches orbit with its payload and remains high until atmospheric drag lowers it uncontrollably.
We’ve seen such falls after the two previous Long March 5B missions, which began in May 2020 and April 2021. Rocket body Fell over an empty ocean After liftoff in April 2021, but the May 2020 mission resulted in a crash that spread debris over parts of West Africa. And some of these spaceflight hardware apparently I got to land in Ivory Coast (Opens in a new tab).
Editor’s note: This story was updated at 3:40 PM ET on July 29 with the latest forecast from the aerospace company.
Mike Wall is the author of “Abroad (Opens in a new tab)Book (Great Grand Publishing House, 2018; illustrated by Carl Tate), a book on the search for extraterrestrials. Follow him on Twitter Tweet embed (Opens in a new tab). Follow us on Twitter Tweet embed (Opens in a new tab) or on Facebook (Opens in a new tab).
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