B.C. researchers have found there is a 26 per cent chance space junk will re-enter the atmosphere and pass through a busy airspace filled with passenger jets — including Metro Vancouver.
The resulting closures could cost the aviation industry and the people who rely on it millions of dollars per hour. Ignoring the threat, on the other hand, could one day be deadly, found the study, recently published in the journal Scientific Reports.
“We found that there's about one per cent risk of a re-entry over the really high-density airspace, like around airports,” said Ewan Wright, a PhD researcher focusing on uncontrolled re-entries at the University of British Columbia.
“That rises to about a 26 per cent chance of a re-entry in busier air spaces, such as the Northeastern U.S., over Vancouver-Seattle and Northern Europe.”
Wright and his two UBC colleagues used space junk tracking data published by the U.S. military in the decade leading up to 2023. They compared the falling orbital debris with flight data from commercial aircraft. The resulting model showed just how likely a hurtling piece of old rocket could shut down an entire airspace.
In recent years, space programs around the world are launching more rockets every year, said Wright, who led the study. Most of the time, they remain in orbit.
“It could be hours later, or it could be months, or years later — that rocket comes back down,” he said.
Recent ground strikes, airspace closures raise prospect of danger
Wright’s past calculations show there’s a three to four per cent chance someone on the ground will get hit by falling space junk — a prospect made plain to Canadians last year when a suspected piece of an unpressurized cargo trunk from the SpaceX Dragon capsule was found in a farmer’s field near Ituna, Sask.
On March 8, 2024, another piece of equipment that was part of a 2,630-kilogram load of used batteries jettisoned from the International Space Station survived re-entry and slammed into a house in Naples, Fla. The potato-sized metal cylinder went straight through Alejandro Otero’s roof while his son, Daniel, was in a nearby room, according to a legal claim later made against NASA. Nobody was hurt and the space agency said it had launched an investigation to understand how the space garbage didn’t burn up.
When it comes to the chance of space junk crashing into an aircraft, the odds drop to one in 430,000, a very unlikely risk, the UBC study found.
But according to Wright, it’s much more likely that there will be disruptions to airspace. That’s because air traffic controllers will see a re-entry happening and face a dilemma — keep the airspace open and risk an aircraft getting hit, or close it and risk millions of dollars in losses due to delays, said Wright.
Such precautionary measures occurred in 2022 when the European Space Agency tracked a piece of an old rocket as it ostensibly hurdled toward France and Spain. The two countries closed their airspace for up to an hour, delaying about 600 flights.
In the end, the hard-to-track space junk landed on the other side of the world in the Pacific Ocean. Wright said such events are much more likely to occur in the future.
His study found air spaces with a lot of traffic were most at risk — including urban regions across Asia, Europe and North America.
Space junk is a dangerous choice
Wright spoke to BIV from Vienna, Austria, where he’s presenting some of his research to the United Nations' Committee on the Peaceful Uses of Outer Space — a group that has existed since the 1950s, two years after the Soviet Union launched the Sputnik satellite and ignited the first space race.
The researcher said he’s at the U.N. meeting to listen and try to convince people of the urgency to act. It can be a hard sell, he said, especially to nations whose space programs are once again in competition with each other and who don’t want to restrict their technology.
“What we're kind of heading towards, I think, is potentially having more and more disruption, or maybe someone on the ground gets hit by space debris, and then we'll see some action on the issue,” Wright said. “It’s a choice. We don't have to leave space debris in orbit.”
If countries and rocket manufacturers chose to act, they could start by carrying out more controlled re-entries — where you either blast the rocket back into the ocean, or like some new rockets, bring them back to the surface in a controlled landing.
Of course, that doesn’t solve the problem of the more than 2,000 upper-stage rockets still in orbit — a number that is growing every year. In 2024, there were a record 120 upper-stage re-entries, more than at any point in history, said Wright.
“If you're an airspace authority, you should have a plan for what's going to happen,” he said. “Because what we saw in 2022 [in Europe] was that the states were sort of scrambling that morning to close their airspace, and they didn't quite know what to do.”
Debris removal efforts yet to take off
In an email, a spokesperson for Nav Canada said it relies on notifications from Transport Canada and the Canadian Space Agency (CSA) to shut down its airspace.
“Would a restriction be put in place, Nav Canada would provide assistance in helping air operators avoid the area (as we would with any restricted airspace),” said spokesperson Maryam Amini in an email.
According to the CSA, Canada has regulations that require satellites to have a disposal plan at the end of their missions. The space agency has also invested in new technologies to better track space debris, according to recent contracts.
CSA spokesperson Frédérick Fink said the agency uses two tracking satellites and works with National Defence, Transport Canada, and “international stakeholders” to manage space debris. The spokesperson did not comment on whether the space agency is accelerating its ability to track de-orbiting space junk.
In the United States, NASA has its own Orbital Debris Program. Based in Houston, Texas, the program is tasked with preventing the accumulation of space junk while designing equipment to track and remove it once in orbit.
Over the years, some have proposed solutions to capture orbital debris, including deploying giant nets, harpoons, and even space robots that would attach to an object and pull it into the atmosphere. To date, however, “no U.S. government entity has been assigned the task of removing existing on-orbit debris,” states the program’s website
In 2023, the European Space Agency adopted the Zero Debris Charter, which seeks to gain international support and develop technology to eradicate space junk by 2030.
“Space is really good for bringing states together, even when they are potential adversaries on the ground,” said Wright.
At the moment, he said there’s a lot of tension around the moon, including how countries can operate there without hiving off into zones or deploying military assets. One thing Wright and his colleagues are pushing for in Vienna is a joint scientific mission to the far side of the moon.
The idea, he said, is to enter a radio quiet zone, build a scientific observatory, and as he put it, “sort of bring people together.”
–With a file from the Canadian Press
