Look alive out there.
Add rockets to the list of reasons to look both ways before crossing the street — or doing just about anything outdoors and under the cover of an untenable structure.
The billionaire space race, commercial spaceflight and the use of satellite technology are upping the odds of being crushed by a falling spaceship, a new study published in Nature Astronomy warned on Monday. Scientists estimated a nearly 10% risk that a free-falling rocket will indeed kill someone on the ground during the next decade.
The risk increases depending on where you stand, according to researchers, especially for those in the Global South, who are likely to see a greater proportion of space junk land around their home, simply due to the Earth’s rotation and the way in which launches are conducted.
“It’s a statistically low risk, but it’s not negligible, and it’s increasing — and it’s totally avoidable,” lead study author Michael Byers, a professor in the Department of Political Science at the University of British Columbia, told The Verge. “So, should we take available measures to eliminate casualty risks? I think the answer should be yes.”
Rockets are built to fall apart as they propel themselves away from the planet, some of which ends up floating in space (threatening astronauts) while others descend back to Earth. As they pass each atmosphere, they shed dead weight used in various “stages,” consisting of fuel tanks, boosters and other parts only needed during initial launch. That’s one reason why most launches take place near coastlines — so rocket junk falls safely to the ocean.
The fear became all too real in 2020, when a 12-meter-long pipe and more debris from China’s Long March 5B rocket found it’s way to Africa’s Ivory Coast, landing across two villages though — fortunately — killing no one.
It almost happened again last year when a 100-foot-tall part of a Chinese rocket, that weighed 20 metric tons, made a close call as it zoomed past cities including New York and Madrid before ultimately landing in the Indian Ocean. The incident inspired Byers and his team’s research, they said.
Galactic travel entrepreneurs such as Elon Musk‘s SpaceX have sought a more economical approach to space flight, by guiding these parts back to retrievable zones where they can be reused for another launch, though he’s still working out the kinks as well. In 2015, one of their launches discarded two fuel tanks the size of refrigerators, both of which landed in Indonesia.
An analysis of the previous 30 launches revealed that cities including Jakarta, Mexico City, and Lagos are three-times or more likely to be hit by wayward rocket junk when compared to cities more North of the equator, such as New York City, Washington D.C. or Beijing.
“The risk at an individual level is really, really small … [but] if you’re living in a densely populated city at 30 degrees north latitude, then it should be of more concern to you,” Byers explained, as most drops occur along the equator — a move that aids satellite tracking. Also, there are several densely populated cities along the equatorial line, contributing to an individuals’ “significantly increased risk” in those areas.
Researchers reminded that potential death by falling rocket trash is preventable with government legislation and funding, such as an international agreement to move smaller payloads, conserving enough fuel to direct pieces safely down to Earth. Researchers cited the 1987 Montreal Protocol as an example of a successful collective effort, which rid the world of ozone-depleting substance and mended our planet’s shield against UV rays.
“The general practice with regards to aviation is to maximize safety. And we believe that same approach should be taken to space launches,” Byers said.