Space debris, apparently from China and a SpaceX NASA mission, fell to Earth and crashed on land.
There is a 10% chance that a person will be hit by falling space debris within a decade, researchers calculated.
Experts say controlled reentries, studies of fallen debris and warning systems can reduce those odds.
It’s raining rocket parts, and space junk experts fear that one day some of the debris falling from Earth’s orbit will hit a person.
The booster of a 25-ton Long March 5B rocket, which pushed part of China’s new space station into orbit in late July, crashed back to Earth on Saturday.
Although some of the booster likely burned up as it plunged through Earth’s atmosphere, reports suggest parts of the rocket may have survived the fall and crashed near inhabited areas of Borneo, an island in Southeast Asia. Debris was found on both the Malaysian and Indonesian sides of the island, as well as in the sea close by The Philippines. The locations of the debris reports were along the trajectory of the booster’s re-entry into the atmosphere, previously calculated by orbital debris experts.
“They certainly look like rocket parts to me,” Ted Muelhaupt, a consultant for the Aerospace Corporation’s Chief Engineer’s Office, told Insider, adding, “I have no reason to dispute that they are parts of this rocket.”
In July, a shepherd in Australia spotted a mysterious piece of debris sticking out of the ground, nearly 10 feet high. On Wednesday, the Australian space agency said the giant piece of hardware came from the discarded trunk of a SpaceX Crew Dragon spacecraft, which carried astronauts for NASA last year.
Only China and SpaceX can confirm that these pieces come from their spacecraft. But experts like Muelhaupt say they believe the reports.
“There’s no doubt in my mind,” Jonathan McDowell, a Harvard astronomer who meticulously tracks objects in Earth’s orbit, told Insider.
These are just a couple of striking examples of a widespread phenomenon. Every day, several man-made objects fall out of orbit and back to Earth, according to Muelhaupt, who works on the Aerospace Corporation’s reentry database.
Many space objects burn up in the atmosphere, but pieces of material regularly survive the fall. Experts at the Aerospace Corporation say that up to 40% of the mass of a large space object falling from orbit will reach the ground. About once a week, an object weighing at least 1 ton falls from orbit and re-enters the atmosphere, Muelhaupt said.
In a study published in the journal Nature in July, researchers calculated a roughly 10% chance that debris will hit one or more people over a 10-year period.
“If you roll the dice too many times, somebody’s going to get lucky,” McDowell said.
Crowded skies mean more falling space debris
Typically, after a launch, rocket boosters push themselves into the farthest part of the Pacific Ocean – a process called “controlled reentry”. Smaller discarded objects, such as the trunk of a Crew Dragon, will either burn up in the atmosphere or enter Earth orbit and stay there.
But in the case of the Long March 5B, China did not design the rocket booster for controlled reentry. Instead, it fell back to Earth randomly each of the three times it was launched. In May 2020, debris from one of these rockets was discovered near two villages in Côte d’Ivoire, reportedly causing property damage.
The Long March 5B boosters are among the largest objects to fall back to Earth, but uncontrolled reentry is not unique to China. In 1979, NASA’s Skylab space station crashed rapidly, scattering debris over Australia. Today, however, controlled reentry is standard practice.
Despite the increase in space activity in recent years, decommissioned space objects are increasingly being brought down to Earth under control. “Whereas 30 years ago, a rocket stage would have remained in orbit and made an uncontrolled reentry a few years later,” McDowell said.
Still, Muelhaupt fears there will be more frequent incidents of falling debris – like the part of Crew Dragon that landed in Australia – in the future. In space travel, the standard acceptable level of risk to human life is one in 10,000. But when companies like SpaceX plan to send tens of thousands of satellites into orbit, those odds mean that a few of them will drop bits of metal to Earth.
Between more companies launching satellite constellations and more space agencies flying spacecraft, there is an increasing chance that debris will land in a densely populated place.
“You do it often enough, you do it long enough, you’re going to get lucky and bring it down in the middle of a city park,” Muelhaupt said.
Take out the room trash
For now, the best way to prevent a space debris disaster is to convince all countries and companies to commit to practicing controlled re-entry.
“The People’s Republic of China did not share specific trajectory information when its Long March 5B rocket fell back to Earth,” Bill Nelson, NASA Administrator, tweeted Saturday, adding that all spacefaring nations should engage in responsible space behavior.
“Doing so is critical to the responsible use of space and to ensuring the safety of people here on Earth,” Nelson added.
Companies and space agencies can also study space debris to find out why it fell from orbit, and why certain parts of it didn’t burn up along the way. For example, Muelhaupt said the largest piece of suspected SpaceX debris in Australia is a section where metal connects to carbon fiber. Why that appendage broke from the rest of the spacecraft and survived the fiery plunge to Earth is a question Muelhaupt wants answered.
“I hope they go get it and then tell us,” Muelhaupt said.
A better understanding of debris fall can help inform real-time warning systems, both for people on the ground and for people flying airplanes. With airliners criss-crossing the planet at all times, there should be a warning about space debris for pilots, Muelhaupt said. A collision is unlikely, but if it did happen the damage would be catastrophic, especially for a commercial flight carrying passengers.
“The chances of hitting an unprotected person standing in the open is one thing, but you get a plane on the run, now suddenly the consequences are much greater,” Muelhaupt said.
He fears it will take a catastrophe to pressure regulators and companies to make real change.
“I hate to say it: When something bad happens to somebody, that’s when we react,” Muelhaupt said.
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