In the next few days, a 23-ton piece of rocket will fall to Earth at 15,000 miles per hour. Much of it may burn on re-entry, but not much of it will.
It could land as a single piece but most likely the same, spread out over an area of several hundred miles. Scientists have narrowed the potential impact zone to within latitudes 41°N and 41°S, an area that covers most of the United States, South America, Africa, the Middle East, most of Asia, and all of Australia except for the island of Tasmania.
Beyond that, the predictions are questionable.
“A few hours after it re-enters the atmosphere, we’ll know where it is,” said Dr. Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. “A few hours before you know the right time in three hours…but at that time the rocket is traveling all the way around the Earth at 17,000 miles per hour. So, if you’re out for an hour, you’re also 17,000 miles away.”
In all likelihood, the space junk, which was dumped from China’s Long March 5B launch last Sunday, will not reach a populated area. Although 80% of the world’s population lives in the danger zone, only 0.1% of them are considered inhabited.
Everything else is ocean, forest or farmland,” said Dr. Shane Walsh, a research fellow at the International Center for Radio Astronomy Research. “It is extremely unlikely to cause damage or loss of life.”
Space watchers may not be too concerned, but they aren’t entirely happy about the situation. Experts say the impact would be akin to a small plane crash, and potentially much less lethal than the missile strikes and accidents that happen elsewhere every day. But the risks can be mitigated.
Sunday’s launch was the third in the 5B series, with a new lab unit delivered to the Tiangong space station. Most nations’ missiles separate the launcher from the payload before leaving the atmosphere, with an additional motor on the payload giving the final thrust and allowing the launcher to fall in a more predictable manner.
But it appears that China does not want to spend weight on a second engine, and its 5B missile – one of the largest in use – is instead pushing all of it into orbit before separating. The launch section then travels the size of a bus through orbit for days or weeks before re-entering Earth’s atmosphere. somewhere.
In May 2020, two villages in Ivory Coast were hit by objects – including a 12-meter section of pipe – that appears to have come from the Chinese ship Long March 5B that was expected to land that day.
After a second 5B bomber landed unharmed in the seas near the Maldives last year, NASA Administrator Bill Nelson accused China of “failing to meet responsible standards regarding its space debris”.
Chinese authorities reject this accusation. Chinese Foreign Ministry spokesman Zhao Lijian said this week that China’s space exploration has always acted “in accordance with international law and … customary practices”, and that 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 up upon re-entry.
“They claimed to have learned from the last two launches and added some control methods, but the EU’s tracking network has shown that this unit is faltering, which means it is unmonitored,” Walsh said.
Professor Zhao Chi-kwang, head of the Department of Space Science at National Central Taiwan University, noted that uncontrolled re-entry operations are taking place with debris hitting Earth, and not just by China. And NASA is known to have been fined $400 for dumping when parts of its Skylab space station hit Western Australia in the 1970s. (Still not paid.)
Zhao said the launches in China were more unexpected, with greater cuts, and “of course people are afraid in this case,” but he also accused the media of panic. People think that there is something heavy and big above our heads. But I believe that if China can prevent the damage, it will prevent it.
In the event that the wreck collides with something or, even worse, a person, the affected persons will be responsible for compensation. But other than that, there are no international rules to prevent or restrict uncontrolled re-entries.
“It’s an interesting thing about space law that if you do harm you are responsible for it, but if you do something very risky and get away with … then you get away with it,” McDowell said.
The US and EU have included risk assessments and will not be released if there is a greater than one in 10,000 chance of causing infection. 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 missile launched in February. Launches from the indoor Xichang satellite launch site routinely drop debris on communities, with officials issuing evacuation notices to residents to “quickly adjust your location.”
Walsh said China is rightly proud of its space program, and the launches should be a public relations coup. Instead, there are global addresses for varying levels of alert.
McDowell Walsh hopes the poor publicity will encourage changes to future launches. “I think they’re a little embarrassed because of the bad publicity,” McDowell said. I think they know this is a problem now. They may never admit it but maybe – not to mention – we’ll see the next generation [of rockets] They will be better disposed of and re-enter more safely.”
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