May 29, 2023
Heads up: Another Chinese missile falls back to Earth

Heads up: Another Chinese missile falls back to Earth


For the fifth time in less than three years, a massive Chinese rocket stage is expected to plunge to Earth, perhaps as soon as Friday.

The odds of someone being hit by returning space junk are extremely low, less than the odds of winning the lottery, says Ted Muelhaupt, a consultant in the office of the chief engineer at the Aerospace Corporation, a nonprofit that has plotted possible return paths. rocket.

But several of those routes pass over a large portion of Earth’s inhabited areas, meaning there’s still a chance someone could be injured by the missile’s return. And that raises another question: Why does China, alone among spacefaring nations, allow its boosters to return unscheduled, instead of dumping them into the sea, as most others do, or returning them to a smooth landing, like Space X?

NASA Administrator Bill Nelson has repeatedly condemned China for its behavior. In a statement last year, he said the Chinese were acting irresponsibly. “Space-faring nations must minimize risks to people and property on Earth from re-entries of space objects and maximize transparency about these operations,” he said. “It is clear that China is failing to meet responsible standards regarding its space junk.”

“The technology exists to prevent that,” Muelhaupt said. The rest of the world “doesn’t purposely launch things that big and intend for them to fall anywhere. We haven’t done that in 50 years.”

The booster of China’s massive Long March-5B rocket stays aloft for several days after launch and then crashes back to Earth, falling out of control. This was launched on Monday, carrying the last module of the Tiangong space station that China is assembling into Earth orbit.

As of Wednesday, Aerospace Corporation calculations had the stage likely to land in land areas where 88 percent of the world’s population lives. And so the chance of casualties, Muelhaupt said, is between 1 in 230 to 1 in 1,000. This risk far exceeds the internationally recognized standard that says an object reentering space should have no more than a one in 10,000 chance of causing injury.

The Chinese rocket stage is huge — it weighs 22 metric tons and is as long as a pair of 53-foot semi-trailers parked end to end, Muelhaupt said. He estimates that between 10 and 40 percent of the booster will survive re-entry and hit Earth.

After the launch of the Long March-5B in May 2020, a piece of the rocket landed in Ivory Coast in Africa. In July, debris fell in Indonesia and Malaysia. China’s Long March missiles are the third, fourth, fifth and sixth largest uncontrolled re-entries ever made into the Earth’s atmosphere, he said.

NASA has gone to great lengths to ensure that the expendable core stage of its Space Launch System rocket falls into the Atlantic away from people, Jim Free, NASA’s associate administrator for exploration systems development, told reporters Thursday. “We have very clear direction to safely dispose of whatever we put into orbit,” he said. “That’s the core of what NASA does.”

Russian reinforcements drop into designated areas of Kazakhstan and Russia that are uninhabited.

However, persuading other nations to behave responsibly remains a problem. While nations that launch objects into space are liable if they cause injury or damage to the ground, there are no laws prohibiting nations from letting large pieces of debris fall to Earth.

“The reality is that there are no real laws or treaties internationally that govern what you’re allowed to do in terms of re-entry,” said Marlon Sorge, a technical associate at the Aerospace Corporation. “So there’s not really a direct legal way to control what’s going on internationally.”

In other words, there are few, if any, rules of the road that govern the space. Instead, efforts are being made by the Aerospace Corporation and others to create standards that countries with space programs will adhere to.

“Although it’s really difficult, we believe that establishing an international consensus on these rules of conduct in space is absolutely a worthwhile and important endeavor,” said Lael Woods, space traffic management specialist at the Aerospace Corporation.

Meanwhile, space is littered with all kinds of debris, including upper stages from rockets that can remain in orbit for months, even years. While many burn up when they fall into the atmosphere, some survive, at least partially.

Earlier this year, for example, part of SpaceX’s booster landed in Australia, where it was found by a sheep farmer.

“Pretty scary, actually,” Mick Miners told the New York Times. “I was surprised. It’s not something you see every day on a sheep farm.”

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