Another huge Chinese rocket was launched on Sunday at 2:22pm Beijing time, and again, no one knows where and when it will land.
It will be a repeat of two previous launches of the same rocket, the Long March 5B, one of the largest currently in use. A week after launch, the world’s space debris watchers will monitor the 10-story, 23-ton rocket booster as the gusts of air friction slowly pull it back down.
The chance of hitting anyone on Earth is low, but significantly higher than many space experts consider acceptable.
The powerful rocket was designed to launch parts of China’s Tiangong space station. The latest mission raised Vention, a laboratory module that expands the station’s scientific research capabilities. It will add three more berths for the astronauts to sleep in and another plane to carry their spacewalks.
Completing and operating the space station has been described in state media broadcasts as critical to China’s national prestige. But there was some damage to the country’s reputation during the rocket’s earlier flights.
After the first Long March 5B launch in 2020, the booster re-entered West Africa, causing debris damage but no injuries to villages in the country of Ivory Coast.
Booster from the second launch in 2021, It splashed harmlessly into the Indian Ocean near the Maldives. In this case, NASA administrator Bill Nelson criticized the Chinese and issued a statement. “It is clear that China has failed to meet responsible standards regarding their space debris,” he said.
China rejected that criticism with considerable fanfare. Hua Chunying, a senior spokeswoman for the Ministry of Foreign Affairs, accused the US of “exaggeration”.
“The US and some other countries have been discouraging the landing of Chinese rocket launchers for the past few days,” Ms Hua said. “Until today, no damage has been caused by the landing debris. I’ve seen news reports that since the first man-made satellite was launched 60 years ago, there hasn’t been a single incident of a piece of debris hitting someone. American experts put the chances of that at less than one in a billion.
China’s space agencies did not respond to a request for an interview about the upcoming launch.
“The Chinese government has an enormous prestige in space, which sees every major missile as amassing its space power,” said Namrata Koswani, author of “Scramble for the Skies: The Great Power Competition.”
China has overtaken Russia in the sophistication of its space programme, Dr Koswani said. “China has a lead in its Moon and Mars program and military space system compared to the Russian space program,” he said.
On a sunny and warm morning, a crowd of China’s space fans spread across the beach near a rocket launch site on Hainan Island in the country’s south. Others crammed onto rooftops at beach-front hotels.
Zhang Xingyi, 26, set up his camera on a hotel roof with about 30 other people on Sunday morning.
He said this was his 19th trip to chase the Rockets. She booked the hotel four months ago.
“There are more people than ever,” he said.
Ms. Zhang refers to the rocket by a nickname used by enthusiasts: “The Fat Five.” “There will be a small earthquake when it launches,” he said.
China has landed a rover on the far side of the moon, collected lunar material, brought it back to Earth for scientific study, and landed and operated on Mars. The United States is the only country to have accomplished that last feat.
“China hasn’t done anything in space that the US hasn’t done before,” said Joan Johnson-Freese, a professor at the U.S. Naval War College and former director of the Department of National Security Affairs. “But it is reaching a technological equilibrium, which is of great concern to the United States.”
He compared the Chinese space program to a tortoise compared to an American hare, saying, “The tortoise has accelerated significantly in recent years.”
As of this April, China has completed the bulk Six tasks For construction of space station. Three crews of astronauts remain aboard the station, including three that will receive the Vendian module this week.
About 15 minutes after launch, the rocket booster successfully placed the Vendian spacecraft into its intended orbit. It is scheduled to rendezvous with the Tianhe Space Station module about 13 hours later. There is no indication that the Chinese space agency has made any changes to the booster.
“It’s going to be the same story,” said Jonathan McDowell, an astrophysicist at the Center for Astrophysics in Cambridge, Mass. Monitors the arrival and departure of objects in space. “It’s possible that the rocket designers made some small changes to the rocket that would allow them to propel the platform on impulse. But I don’t expect that.”
If the rocket design does not change, no thrust will guide its descent, and the booster’s engines cannot be restarted. The final shower of debris, with a few tons of metals expected to survive to the surface, could occur anywhere along the booster’s path, which travels as far north as 41.5 degrees north latitude and as far south as 41.5 degrees south latitude.
That means there will be no danger to Chicago or Rome, both of which lie just north of the orbital paths, but Los Angeles, New York, Cairo and Sydney, Australia, are among the cities the booster will travel to.
The science of predicting where a bouncing rocket will land is tricky. Earth’s atmosphere swells and collapses depending on how strongly the sun shines on a given day, and this phenomenon speeds up or slows down the fall. If a calculation turns off within half an hour, falling debris has already traveled a third of the way around the world.
By design, Long March 5B’s center booster stage will push a Vendian module, more than 50 feet long, all the way to orbit. That means the booster will also reach orbit.
This differs from most rockets, where the lower stages usually return to Earth immediately after launch. Upper stages that reach orbit usually re-fire the engine after releasing their payloads, directing them towards re-entry into an unoccupied region such as the mid-ocean.
Outages sometimes result in unplanned uncontrolled re-entries Second stage of SpaceX rocket It landed on Washington state in 2021. But the Falcon 9 stage was smaller, about four tons, and less prone to damage or injuries.
America and NASA were not always as careful as they are now when bringing large objects back into the atmosphere.
Skylab, the first American space station It fell to earth in 1979, with large pieces hitting Western Australia. (NASA did not pay the $400 fine for littering.)
NASA also has no plans to decommission the Upper Atmospheric Research Satellite, or UARS, after that mission ends in 2005. Six years later, the dead satellite, the size of a city bus, headed for the other end uncontrollably. -Entry, NASA calculated that 1 in 3,200 could be injured. It’s done falls into the Pacific Ocean.
Typically 20 percent to 40 percent of a rocket or satellite survives without re-entry, said Ted Muelhaupt, a debris expert at the Aerospace Corporation, which is largely funded by the federal government for research and analysis.
That would suggest that 10,000 pounds to 20,000 pounds of the Long March 5B booster could hit the Earth’s surface.
If the chance of injuring someone on the ground is greater than 1 in 10,000, the United States and some other countries avoid uncontrolled reentry of space debris, Mr. Mulhaupt said.
To date, there have been no known cases of human-made space debris injuring a person.
“The 1 in 10,000 number is somewhat arbitrary,” said Mr. Muelhaupt said. “It’s widely accepted, and recently when a lot of objects are re-entering, they add up to the extent that someone is going to get hurt.”
If the risk is too high, “the more common practice is to dump them in the ocean,” said Marlon Sorge, executive director of the Aerospace Corporation’s Orbital and Re-entry Debris Research Center. “That way, you know you’re not going to hit anybody.”
Mr. Mulhaupt said. But “I’m pretty sure it’s over the 1 in 10,000 risk threshold,” he added. “Above the threshold.”
The Long March 5B booster is three times larger than the UARS. A rough guess would be three times the 1 in 3,200 risk estimated by NASA for UARS.
“It’s three UARSs in a way,” Dr. McDowell said. The likelihood of this booster injuring someone is “probably one in a few hundred,” he said.
During a preview broadcast on Chinese state media CGTN, Xu Yansong, a former official of the China National Space Administration, referred to the 2020 Ivory Coast incident. Since then, “we’ve improved our technologies,” he said. The rocket stage must be brought down in an uninhabited area, But he did not give any details.
The same series of events may unfold again soon.
In October, China will launch a second laboratory module, Mengtian, into orbit to complete Tiangong’s assembly. It will also fly on another Long March 5B rocket.
Li You contributed to the research.