As more space junk falls to Earth, will China clean up its act? | China

In the next few days, a 23-ton rocket will crash to Earth at around 15,000 miles per hour. Much of it may burn on reentry, but a significant amount does not.

It could land as one piece but more likely as many, spread over an area up to several hundred miles in diameter. Scientists have narrowed the likely impact zone to latitudes of 41 degrees North and 41 degrees South, a region that covers much of the United States and South America, Africa, the Middle East, most of Asia, and all of Australia with the exception of the island of Tasmania.

Beyond that, forecasts are uncertain.

“A few hours after it re-enters the atmosphere, we will know where it was,” said Dr. Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “A few hours earlier we might know when within three hours… But in that time the rocket circles the Earth at 17,000 miles per hour. So if you’re out an hour, you’re also 17,000 miles away.

In all likelihood, the space junk, discarded by the Chinese launch of Long March 5B last Sunday, will not hit a populated area. Although 80% of the world population lives in the risk zone, only 0.1% is considered populated.

“Everything else is ocean, forest or farmland,” said Dr. Shane Walsh, a researcher at the International Center for Radio Astronomy Research. “It is extremely unlikely to cause harm or loss of life.”

Space observers may not be too worried, but they’re not exactly happy with the situation. The impact will be similar to a small plane crash, experts say, and likely far less fatal than the missile strikes and crashes that occur elsewhere every day. But the risk could be mitigated.

Sunday’s launch was the third in the 5B series, providing a new laboratory module to the Tiangong space station. Rockets from most nations separate the launcher from the payload before leaving the atmosphere, with an additional motor on the payload providing final thrust and allowing the launcher to fall in a more predictable manner.

But China seems unwilling to spend weight on the second engine, and its 5B rocket – one of the largest in use – instead pushes completely into orbit before splitting off. The bus-sized launch section then travels through orbit for days or weeks before re-entering Earth’s atmosphere. Somewhere.

In May 2020, two Ivory Coast villages were hit by objects, including a 12-meter stretch of pipe, which appeared to come from a Chinese Long March 5B that is expected to land that day.

Debris that fell from space in the village of N'Guessankro, in central Ivory Coast, in 2020
Debris that fell from space in the village of N’Guessankro, in central Ivory Coast, in 2020. Photograph: AFP / Getty Images

After the second 5B launcher landed harmlessly in the seas near the Maldives last year, NASA administrator Bill Nelson accused China of “failing to meet responsible standards regarding their space debris.”

Chinese authorities deny the accusation. This week, its Foreign Ministry spokesman Zhao Lijian said China’s space exploration has always acted “in accordance with international law and … custom” and the likelihood of debris causing damage is “extremely low”.

Zhao said the unit was designed with unspecified “special technology” and that the “vast majority” of its components would burn out upon re-entering the atmosphere.

Walsh said: “They claim to have learned from the last two launches and have added some control methods, but the EU tracking network has shown that this unit is collapsing, which means it is not controlled.”

Professor Chao Chi-Kuang, head of the space science department at Taiwan’s National Central University, noted that there have been other uncontrolled returns with debris hitting Earth, and not just from China. Famously, NASA was fined $ 400 for garbage when parts of its Skylab space station hit Western Australia in the 1970s. (He does not payed yet.)

Chao said China’s launches were more unpredictable and with bigger chunks, and “obviously people are afraid in this case,” but he also accused the media of alarmism. “People think there is something very heavy and big above our heads. But I think if China can prevent the damage, it will prevent it, “she said.

If the debris hits something or, worse, someone, those affected will be responsible for the compensation. But otherwise there are no international rules to prevent or limit uncontrolled returns.

“It’s an interesting space law oddity that if you do damage you’re responsible for it, but if you do something risky and get away with it … then you get away with it,” McDowell said.

The US and EU have incorporated risk assessments and will not initiate if there is a chance of causing injury greater than one in 10,000. China appears to have a much lower bar.

In April, villagers in a remote part of India found what appeared to be large parts of a Chinese Long March 3B rocket launched in February. Launches from the Xichang satellite launch site inland regularly rain debris on communities, with officials issuing evacuation warnings for residents to “quickly fix their position.”

Walsh said China is justifiably proud of its space program and that the launches should be a public relations coup. Instead there are global stocks of various warning levels.

McDowell and Walsh hope the bad publicity will encourage changes to future launches. “I think they’re a little embarrassed by the bad publicity,” McDowell said. “I think they know this is considered a problem now. They may never admit it, but maybe we’ll see – without them saying it – the next generation [of rockets] he will behave better and will return safer ”.

Leave a Reply

%d bloggers like this: