Another large Chinese rocket was launched into space at 2:22 p.m. Beijing time on Sunday, and again, no one knows where or when it will land.
It will be a re-enactment of two previous launches of the same rocket, the Long March 5B, one of the largest currently in service. For about a week after launch, space debris trackers around the world will be watching the 10-stage, 23-ton rocket as jets of air friction slowly pull it back.
The chances of it hitting anyone on Earth are low but significantly higher than what many space experts consider acceptable.
The powerful rocket is specially designed to launch pieces of China’s Tiangong space station. The latest mission has lifted Wentian, a lab module that will expand the station’s scientific research capabilities. It will also add three more spaces for astronauts to sleep in, and another airlock for them to conduct their space voyages.
The completion and operation of the space station depicted in the state media is vital to China’s national reputation. However, the country did some damage to its reputation in previous flights of the rocket.
After the first Long March 5B launch in 2020, the booster returned to West Africa, with debris damaging but not injuring villages in the Ivory Coast country.
The boost from the second launch, in 2021, harmless splashing in the Indian Ocean near the Maldives. However, Bill Nelson, the NASA administrator, issued a statement criticizing the Chinese. “It is clear that China is not meeting its responsible standards regarding space debris,” he said.
China has dismissed that criticism with considerable fanfare. Hua Chunying, a senior foreign ministry spokeswoman, accused the US of “hype”.
“The US and some other countries have advertised the landing of Chinese missile debris in the past few days,” Hua said. “So far, no damage from landing debris has been reported. I have seen reports that since the launch of the first artificial satellite more than 60 years ago, there has not been an incident where a piece of debris has hit someone. US experts put that chance at less than one in a billion. “
China’s space agencies did not respond to requests for interviews about the upcoming launch.
Namrata Goswani, author of “Scramble for the Sky: Great Power Competition for Control of Space’s Resources” has great credibility with the Chinese government.
Dr. Goswani said China has surpassed Russia in the level of sophistication of its space program. “China is leading when compared to the Russian space program in terms of the Moon and Mars programs as well as the military space organization,” she said.
On a sunny and warm morning, crowds of Chinese space fans stretched out on the beach near the rocket launch site on Hainan Island in the south of the country. Others crammed on rooftops at hotels along the beach.
Zhang Jingyi, 26, placed his camera on the roof of a hotel with about 30 other people on Sunday morning.
It was her 19th trip to “chase rockets,” she said. She booked her hotel room four months ago.
“There are more people than ever before,” she said.
Ms. Zhang calls the rocket by the nickname used by fans: “Fat Five”. “There will be a small earthquake when it is launched,” she said.
China landed a rover on the far side of the moon, collected lunar material and brought it back to Earth for scientific research, and landed and operated a rover on Mars. The United States is the only other country to achieve that last feat.
“China hasn’t and hasn’t done anything that the United States hasn’t done in space,” said Joan Johnson-Freese, a professor at the US Naval War College and former chair of the Department of National Security. “But it is reaching technical parity, which the US is very interested in”
She likened China’s space program to a tortoise to an American hare, “although the tortoise has accelerated significantly in recent years”.
As of this April, China has completed a total of six missions to build the space station. Three groups of astronauts have lived on the station, including a trio that will receive the Wentian module this week.
About 15 minutes after launch, the booster successfully placed the Wentian spacecraft in its intended orbit. It will arrive at its rendezvous with the Galaxy space station module about 13 hours after takeoff. The Chinese space agency has not given any indication that it has made any changes to the booster.
“It would be the same story,” said Jonathan McDowell, an astrophysicist at the Center for Astrophysics in Cambridge, Mass.. track the arrival and departure of objects in space. “It is possible that the rocket designers could have made some minor changes to the rocket so that they then obligatory debit at this stage. But I didn’t expect that.”
If the rocket’s design remains unchanged, no thrusters will guide its landing and the booster’s engines cannot be restarted. The final shower of debris, with a few tons of metal expected to remain on the surface, could occur anywhere along the booster’s path, going as far north as 41 ,5 degrees north latitude and as far south as 41.5 degrees south latitude.
That means there won’t be any danger for Chicago or Rome, both of which lie a little north of the orbit, but Los Angeles, New York, Cairo and Sydney, Australia are among the cities where the rockets will launch. will pass.
The science of predicting where a falling rocket stage will fall is very complicated. Earth’s atmosphere rises and falls depending on how strong the sun is on a particular day, and that phenomenon either speeds up or slows down the fall. If a calculation is wrong by half an hour, the falling debris has already traveled a third of the way around the world.
By design, Long March 5B’s central booster stage will propel the more than 50-foot Wentian module into orbit. That means the booster will also reach orbit.
This is different from most rockets, where the lower stages typically fall back to Earth shortly after launch. The upper stages reaching orbit often trigger the engines again after releasing their payload, guiding them back into an unoccupied area, like the middle of the ocean.
Malfunctions sometimes cause unintended re-entry, such as the second stage of the SpaceX rocket crashed in Washington State in 2021. But the Falcon 9 stage is smaller, about 4 tons, and less likely to cause damage or injury.
The United States and NASA were not always as careful as they are now when it comes to re-entering the atmosphere with large objects.
Skylab, America’s first space station, fell to Earth in 1979, with large pieces hitting Western Australia. (NASA has never paid a $400 fine for littering.)
NASA also has no plans to dispose of the High Atmospheric Research Satellite, or UARS, after the end of that mission in 2005. Six years later, when the satellite is dead, it’s about the size of a bus. city, went in an uncontrollable direction. -entry, NASA has calculated the chance that 1 in 3,200 people could be injured. It is over fell in the Pacific Ocean.
Ted Muelhaupt, a debris specialist at Aerospace Corporation, a federally funded nonprofit that is largely funded by the federal government, said:
That could suggest that between 10,000 pounds and 20,000 pounds of the Long March 5B booster could hit the Earth’s surface.
Mr. Muelhaupt said the United States and several other countries avoid uncontrolled re-entry of space debris if the likelihood of injury to someone on the ground is higher than 1 in 10,000.
To date, there have been no known cases of people being injured by falling man-made space debris.
“That 1 in 10,000 is a bit arbitrary,” Mr. Muelhaupt said. “It’s been widely accepted, and recently there’s been concern that as more objects re-enter, they increase to the point where someone will get hurt.”
“That way you know you’re not going to hit anyone,” said Marlon Sorge, executive director of the Aerospace Corporation’s Center for Orbital Debris Research and Re-entry.
Mr. Muelhaupt said that without detailed information on the design of the Chinese missile, it would be impossible to calculate a risk estimate. But “I strongly believe this is above the threshold” of a 1 in 10,000 risk, he added. “Higher than threshold.”
The Long March 5B booster has three times the mass of the UARS. A rough guess would be that it poses 3 times the 1 in 3,200 risk that NASA has estimated for UARS, perhaps higher.
“These are three UARS in a sense,” said Dr. McDowell. The chance of the booster injuring someone, he said, “could be as high as one percent.”
In a pre-launch broadcast on CGTN, a Chinese state media agency, Xu Yansong, a former official of China’s National Space Administration, mentioned the 2020 incident in Ivory Coast. Since then, he says, “we’ve improved our technology” take down a missile in an uninhabited area, but he did not give specifics.
The same sequence of events could be happening again soon.
In October, China will launch a second laboratory module named Mengtian into orbit to complete the assembly of Tiangong. It will also fly on another Long March 5B rocket.
Li You have contributed research.
