How space junk is causing chaos back on earth

On March 8, 2024, a mysterious hunk of metal crashed into Alejandro Otero’s home in Naples, Florida. “Tore through the roof and went thru 2 floors,” Otero wrote in a post on X, alongside photos of the damage. “Almost [hit] my son.” At the time, space enthusiasts suspected that the object was something to do with the International Space Station – specifically, a battery pallet jettisoned during maintenance in 2021. A month later, on April 15, they got their answer. The hardware was in fact part of the ISS, admitted NASA, identifying it as part of its own flight support equipment, which was supposed to burn up as it reentered Earth’s atmosphere. But it didn’t! And instead it smashed through someone’s roof! And almost obliterated a child!

This would be less than ideal even if it was a one-off occurrence, but the thing is… it’s not. On February 21, 2024, a whole European Space Agency satellite – the defunct ERS-2 – also tumbled back to Earth in an “uncontrolled atmospheric reentry”. Luckily (unless you’re a dolphin) it ended up in the ocean, but the exact location was essentially left up to chance. A couple of years before, ironically, ESA had joined NASA in criticising China for a similar reentry of a used-up rocket booster. To sum up: this isn’t unusual, as a way to get rid of unwanted space junk, but it isn’t exactly reassuring either. As the space sustainability researcher Ewan Wright told Space.com in the aftermath of ERS-2’s crash landing: “We shouldn’t be relying on luck to mitigate casualty risks.”

Back to the spectre that’s lurking just beyond Earth’s atmosphere, though. “90 per cent of everything that we track is trash,” says Jah. “These things stay in orbit for very long periods of time.” (Without intervention, for example, the ERS-2 satellite could have spent 100-200 more years circling Earth.) Once their mission is over, these dead objects are essentially left to float uncontrolled, following their predetermined paths. Jah describes it like being in a car on a highway, and you run out of fuel – only, because you’re in space, there are no forces to slow you down. “Instead of the car slowing down and going to the side, it just keeps on going at speed.”

Right now, there are a lot of these “driverless cars,” he says, which pose a “hazard” to active satellites and other space missions. Without sufficient oversight, a major accident seems inevitable. Remember: satellites are responsible for many processes that have become a fundamental part of our daily life, like financial transactions, monitoring weather and mapping climate change, or the navigation app in your phone. Needless to say, we don’t want any of this to be smashed to smithereens by space-based flotsam and jetsam.

So what are space agencies, or private companies like Elon Musk’s SpaceX, doing to mitigate the risks? Well, they’re blasting new satellites into orbit at a reported rate of around 50 per week, with SpaceX launching 472 of its Starlink v2 Mini satellites in the first quarter of 2024 alone. (Though these are equipped for collision-avoidance manoeuvres, they’ve also been spotted tumbling out of the sky.) As many as a million satellites are planned to launch in coming decades. That’s a lot of “driverless cars” and, even beyond the atmosphere, Earth’s orbital highways only have so much space.

This is why reentry is necessary: to declutter satellites’ paths around our home planet and free up space for new (and probably very useful) projects in the future. This is not a sustainable solution, though. Currently, the odds of any individual human getting hit by falling space junk is “near zero,” Jah admits. “The thing is, those odds are changing on a daily basis.” As more and more space junk falls out of orbit, he says, some of it will inevitably hit land, and some of that land will include populated areas. In fact, it’s already happened – for proof, just look at the photos of Alejandro Otero’s house.

Even if space junk doesn’t hit land, that doesn’t mean we can just forget about it. Most uncontrolled reentries are timed in the hopes that the object lands somewhere close to Point Nemo, the point in the ocean that’s furthest from dry ground. Does that make it ok? Not really! “Basically, we’re saying it’s ok to trash our oceans,” says Jah. “A lot of these dead rocket bodies carry toxic waste, and these things end up polluting the ocean or land where they make impact.” Perhaps the worst example is Kosmos 954, a Russian satellite that scattered radioactive waste over northern Canada when it crashed in 1978.

Even if the junk burns up in the atmosphere on entry – another ‘ideal’ outcome at the end of a space mission – the potential harm is unpredictable, at best. In 2023, researchers found traces of vaporised metal from burned-up space junk in Earth’s atmosphere for the first time, and are still working to determine the potential effects. A recent paper even suggests that reentries could produce a “global band of plasma dust” that disrupts our magnetosphere, with disturbing consequences for our planet’s habitability.

“People are thinking five years out from now, at best […] I feel that we are choosing self-extinction, and it doesn’t need to be that way” – Moriba Jah

That said, humanity is not going to stop going to space. For one thing, we’re way too accustomed to the luxuries brought to us by orbital technologies. But this raises an important question: what, exactly, are we doing about space junk? Well, some researchers have suggested using AI-powered lasers to nudge debris out of collision course, or a massive magnet. Others have proposed a “skyhook” that could be used to winch in space junk and recycle it on Earth. For Jah, though, the solution will only come with a broader cultural shift.

“Right now, everything that we launch is like a single-use plastic,” he says. “Just like we try to minimise single-use plastics here on the surface, we would like to incentivise, encourage, and promote re-use and recyclability in space.” This wouldn’t mean shutting down new innovations in spaceflight, but using Jah’s vision of a circular space economy to guide their development. And yes, this might mean taking time to pause every now and again. “Mother Earth provides feedback about the unintended consequences of our actions,” he explains, adding that right now: “We’re making decisions that are outpacing that feedback mechanism.” Ultimately, though, it would be about correcting past mistakes with a combination of new technology and ancient wisdom.

In some places, we can already see these technologies coming into being. In the last few years, SpaceX has made significant strides when it comes to reusable rockets, while major space agencies have trialled systems for repurposing and recycling materials in situ, with the aim of constructing habitats and roads out of the lunar (or, one day, Martian) surface. However, Jah’s biggest cause for hope as a “celestial steward” is the reaction he receives from people back on Earth, when he makes his case about space environmentalism. “I think I’m making sense,” he says. “When I talk to people, [they’re] like, ‘Oh, yeah, that’s a no-brainer.’” This, he says, is his main goal: “Get people out of their flight-or-flight survival brain, so they can think beyond today, or five years from now, and see that the only way it’s going to work is if we make this shift.”