Concerns are growing that a Chinese space rocket’s uncontrolled re-entry into the Earth’s atmosphere could scatter debris over populated parts of the United States.
The Long March 5B booster is too large to burn up on entry and will break apart, potentially showering the ground with chunks of metal speeding along at terminal velocity.
According to the Center for Orbital and Reentry Debris Studies (CORDS), “over 88% of the world’s population lives under re-entry’s potential debris footprint”.
Experts at CORDS from the Aerospace Corporation have warned that as a “general rule of thumb… between 20-40% of the mass of a large object will reach the ground” depending on the object.
In the case of the Long March booster, which weighs 23 tonnes, this means that between 4.6 and 9.2 tonnes will hit Earth – the equivalent of a dozen 1963 Volkswagen Beetle cars.
In a Q&A on the Aerospace Corporation’s blog, the company said the booster is one of the largest objects to re-enter Earth after reaching orbit.
Most of the time, rocket boosters are not designed to reach orbit, but to launch their payload into orbit while landing in a safe location.
When spacecraft are de-orbited, it is usually done in a controlled manner, with the engines fired to drop the craft into Earth’s orbit and choose where to land—often the so-called “spacecraft graveyard” at Point Nemo in the Pacific Ocean.
This is known as a controlled re-entry where the ultimate landing point and debris footprint can be chosen by the operators.
However, in the case where the booster has entered orbit and will fall back to Earth naturally, its final landing site will not be known until just hours before it hits land.
It is not the first time a Chinese booster has threatened populated areas when it crashed back to Earth, with similar uncontrolled re-entries taking place in 2021 and 2020.
In May 2020, parts of the booster came down over Ivory Coast, according to an analysis by astronomer Jonathan McDowell, damaging several buildings, but no one was injured.
In an article responding to the latest concerns, China’s state-owned Global Times newspaper claimed the Western media response showed “sour grapes”.
The paper also claimed that China had a “flawless safety record” regarding its uncontrolled re-entries, despite McDowell’s analysis.
It added that the criticisms were smears designed to undermine China’s successes in the space sector because the US is “running out of ways” to stop this development in other ways.