“Irresponsible”: Beijing criticizes the uncontrollable Chinese rocket approaching Earth

No, the safest thing is that a rocket fragment will not fall on you, with 23 tons of weight and 10 floors high, who returns to Earth.

That said, the odds are not zero. Part of China’s largest rocket, the Long March 5B, It gets out of control in orbit after a section of the country’s new space station launched last week. The rocket is expected to hit Earth in what is called an “uncontrolled reentry” on Saturday or Sunday.

Whether it falls harmlessly into the ocean or hits inhabited land, it’s not clear why the Chinese space program let this happen -again-. And given China’s planned launch schedule, more of these runaway re-entries are likely to occur in the years to come.

The country’s space program has made a number of significant spaceflight accomplishments in the past six months, including returning rocks from the moon and putting a rover into orbit around Mars. Yet it continues to present a danger, however small, to populations around the world by not controlling the trajectory of the rockets it launches.

“I think it is negligence on their part”, said Jonathan McDowell, an astrophysicist at the Center for Astrophysics in Cambridge, Massachusetts, which monitors the whereabouts of objects in space. “I think it is irresponsible.”

The piece that will fall from the sky is part of the central platform of the Great March 5B, designed to lift the large and heavy parts of the space station. Lower stages usually return to Earth immediately after launch. Upper stages that reach orbit restart the engine after releasing their payloads, guiding them as they reenter an unoccupied area, such as the middle of an ocean.

In the past three decades, only China has put rocket stages of this size into orbit and then dropped them somewhere at random, McDowell said.

For the Long March 5B engine, this random location could be between 41.5 degrees north latitude and 41.5 degrees south latitude. That means Chicago, located a fraction of a degree further north, is safe, but cities like New York could be affected by debris.

On Thursday, the Aerospace Corporation, a largely federally funded nonprofit that conducts research and analysis, predicted the re-entry would take place at 11:43 p.m. ET (1:43 a.m. Sunday in Argentina) on Thursday. If this is correct, debris could fall on northeast Africa, Sudan.

There is great uncertainty around the time – around 4 p.m. – and the location. The aerospace company’s prediction on Wednesday placed re-entry more than an hour earlier, over the eastern Indian Ocean.

The moment when the fragment catches fire depends, for example, on the sun. An increase in the intensity of the solar wind – laden with particles emitted by the sun – would inflate the Earth’s atmosphere, increasing the atmospheric resistance of the thruster and accelerating its fall. The fall of the rocket fragment also complicates the calculations.

The US Space Command and the Russian Space Agency monitor the core of the rocket. A statement from Russia noted that re-entry would not affect the territory of the Russian Federation. Space Command has promised regular updates before a possible re-entry.

As the thruster travels nearly 30,000 kilometers per hour, a minute of change moves debris hundreds or thousands of kilometers. Only a few hours before the start of the school year, the predictions become more precise.

“It’s an engineering decision based on probabilities,” McDowell said. He said that Chinese engineers could have designed the trajectory to remain suborbital and fall back to Earth just after launch, or they could have planned an additional motor to pull to pull it out of orbit in a safe way.

“It’s no small feat to design something for a deliberate reentry, but it’s something the world responded to because we needed it,” said Ted J. Muelhaupt, senior director of the Aerospace Center for orbital debris and reentry studies.

China is planning many more launches in the coming months as construction of the country’s third space station, called Tiangong, or “Heavenly Palace,” is completed. This will require additional flights of the massive rocket and the possibility of more uncontrolled re-entries that people will nervously watch out for, although the risk of impact is minimal.

“It is in the common interest of all nations that we can act responsibly in outer space to ensure the long-term security, stability and sustainability of our activities in outer space,” Jen Psaki, a White House spokeswoman, said Wednesday, adding that the United States hopes to promote “responsible space behavior.”

Falling debris has long hampered spaceflight.

In March, a scene of a SpaceX Falcon 9 rocket lit up the night sky over Seattle, then threw debris on a Washington state farm when firing from the second-stage engine slated to bring it down. safely did not go as planned.

China, on the other hand, has a long history of dropping fragments of its space equipment anywhere.

Rockets from one of China’s main launch sites, the Xichang Satellite Launch Center in Sichuan Province, have regularly landed in rural areas and occasionally caused damage. Since then, China has moved many of its launches, including last week’s one, to a new location in Wenchang, a city in Hainan, an island off the southeast coast. From there, the rocket stages can fall into the sea without causing damage.

In this case, however, the rocket core carrying the module for China’s new space station also entered orbit and has since been slowly swept into Earth’s atmosphere.

Last year, the first launch of a Long March 5B rocket raised a prototype of the Chinese manned space capsule. The propellant of this rocket also made an uncontrolled reentry, and debris fell on a village in Côte d’Ivoire.

This drew a rebuke from Jim Bridenstine, who was then the administrator of NASA. “It could have been extremely dangerous,” He said. “We’re lucky because it doesn’t seem like it affected anyone.”

China’s first space station, called Tiangong-1 and launched in 2011, also fell back to Earth in an uncontrolled descent in 2018 before crashing harmlessly in the South Pacific. The following year, the Chinese space administration succeeded in taking the second station out of orbit and directing it towards the Pacific. This time around, the acceleration phase alone is more than twice as massive as Tiangong’s first two space stations.

The United States also struggled with the return to Earth from its first space station. Skylab, which operated in 1973 and 1974, was dissolved when NASA scientists tried to guide its descent in 1979. The 77-ton station broke mostly over the Indian Ocean, but the debris have spread to Western Australia. President Carter has apologized for the incident.

In 2011, the Upper Atmosphere Research Satellite (UARS), a now missing NASA satellite the size of a school bus, also returned to Earth. NASA has calculated a 1 in 3,200 chance that UARS, slightly smaller than Tiangong-1 or Tiangong-2, will harm anyone.

McDowell said he believes the threat from the debris from the Long March 5B thruster may be comparable, so it’s a cause for concern. Since the Chinese have not provided details on the rocket’s design, it is difficult to predict how much material will fall to the surface.

Muelhaupt noted that it could be 10 tons scattered over hundreds of kilometers. “Imagine three trucks of rubble.”

The largest cascade of space debris to hit Earth’s surface was when the Space Shuttle Columbia disintegrated across Texas as it re-entered the atmosphere on its way to land in Florida . All seven astronauts on board were killed but no one on the ground was injured when 38.5 tons of debris fell in sparsely populated areas.

But if the disaster had happened a few minutes earlier, the spacecraft’s heavy parts, like the engines, would have struck near Dallas at hundreds of miles an hour.

The new Chinese space station is an alternative to the International Space Station. The currently orbiting station, jointly built by NASA, Russia and other partners, has successfully accommodated humans in space for more than two decades. But Chinese astronauts were unable to participate due to US law banning space cooperation with China.

After the launch of what will be the station’s main home on April 29, the Chinese leader, Xi Jinping, He called it “an important pilot project for building a nation that is both technologically and spatially powerful,” state broadcaster CCTV reported.

Since then, Chinese space officials have not commented publicly on how they plan to handle the rampant re-entry, despite global attention and concern.

The Global Times, a Chinese Communist Party-controlled daily quoted scientists and experts as saying there was not much danger and that the space administration had “carefully considered” the possibility of falling debris.

The newspaper, which often reflects the views of extremist officials, said the concern and criticism reflected Western efforts to discredit China’s space program. More launches of the Long March 5B are expected, and unless there is a change in how China operates, the chances of someone being injured by a falling thruster will increase.

“The chance that you win the lottery today is minimal – I bet my paycheck won’t happen – but the odds that no one wins the lottery is a very different bet,” Muelhaupt said. And that’s the thing. The individual risk is minimal, but the risk for everyone is not ”.

Last week’s launch was the first of 11 scheduled for a year and a half to build the Tiangong. In June, three astronauts could fly to the station aboard a Shenzhou spacecraft, in what would be China’s first manned mission since 2016. If all goes according to plan, the space station will be fully operational by then. end of 2022.

The New York Times

The New York Times