The risk of damage is “low”, but not zero: a Chinese rocket must make its return to the Earth’s atmosphere this weekend, without the point of impact of its fall being predictable, even if China and many experts want to be reassuring. The Asian country placed the first module of its space station in orbit on April 29, thanks to a Long-March 5B carrier rocket – the most powerful and imposing Chinese launcher. It is the first stage of this rocket, currently in orbit and which is gradually losing altitude, which must return to Earth.
According to the latest estimates from the US Department of Defense, re-entry into the atmosphere should occur between 9 p.m. Saturday and 9 a.m. Sunday (11 p.m. Saturday-11 a.m. Sunday French time), a forecast which remains uncertain. The window should gradually narrow as the rocket gets closer. For the Russian space agency Roscosmos, entry could be at 11:30 p.m. Saturday (1:30 a.m. Sunday French time) in southern Indonesia.
After a long embarrassed silence from the Chinese space and diplomatic authorities, Beijing finally reacted on Friday. “Most of the components (of the rocket) will be burned and destroyed when it re-enters the atmosphere”, assured Wang Wenbin, a spokesman for the Chinese Ministry of Foreign Affairs. “The probability of causing damage to air activities or (to people, buildings and activities) on the ground is extremely low”, he said at a regular press conference. No forecast on an hourly return potential of the launcher in the Earth’s atmosphere was released.
If parts of the rocket remain intact after re-entering the atmosphere, there is a good chance that they will be damaged at sea because the planet is 70% water. But they could also crash into an inhabited area or a ship. “We hope they land in a place where they won’t harm anyone”said Mike Howard, a spokesperson for the US Department of Defense, on Friday, stressing that the United States was tracking the path of the rocket.
US Defense Minister Lloyd Austin assured this week that his country had no intention of destroying the rocket. He hinted, however, that its launch was not planned with enough care by China.
“Metallic shards”
The risk of heavy launcher debris hitting a populated area exists, but is unlikely. “Considering the size of the object, there are necessarily large pieces that will remain”, anticipates Florent Delefie, astronomer at the Paris-PSL Observatory. But the probability of an impact on an inhabited area is “Tiny, less than one in a million, probably”, reassures Nicolas Bobrinsky, head of the Engineering and Innovation department at the European Space Agency (ESA).
“No need to worry too much”, also notes Jonathan McDowell, astronomer at the Harvard-Smithsonian Center for Astrophysics, in the United States, and great specialist in space debris. “But the fact that a ton of metal shards hit the Earth at hundreds of km / h is not good practice, and China should review the design of Long March 5B missions to avoid this. . “
In 2020, debris from another Longue-Marche rocket crashed into villages in Côte d’Ivoire, causing damage, but no injuries. In April 2018, China’s Tiangong-1 space laboratory disintegrated when it entered the atmosphere, two years after it ceased to function.
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