Picture this: You’re cruising at 36,000 feet, sipping your lukewarm coffee, maybe catching up on a movie. Below, the world is a patchwork of miniature fields and distant cities. Suddenly, with a jolt and a sickening crack, something slams into your plane’s windshield. This isn’t a scene from a disaster movie; it happened just last October to a Boeing 737 over Utah, forcing an emergency landing.
The internet, naturally, exploded with speculation: was it a bird? A rogue drone? Or, perhaps more thrillingly, a piece of space debris? While authorities suspect a weather balloon remnant was the culprit, the online chatter wasn’t as far-fetched as you might think. Because, as unsettling as it sounds, the chance of your plane encountering space junk in the sky, though still small, is actually on the rise.
The Sky Isn’t Just for Birds Anymore: A Growing Cosmic Litter Problem
For decades, humanity has been launching rockets and satellites into orbit, creating an impressive, if messy, celestial junkyard. And that junkyard is getting significantly larger. The European Space Agency (ESA) estimates that about three pieces of old space equipment – think used rocket bodies and defunct satellites – tumble back into Earth’s atmosphere every single day. By the mid-2030s? That daily count could be in the dozens.
This escalating trend is directly tied to the explosion in satellite deployments. Right now, around 12,900 active satellites orbit our planet. Industry analysts project that number could balloon to a staggering 100,000 within the next decade. More objects in orbit inevitably mean more objects eventually falling out of orbit.
Operators try to manage this by guiding old satellites to “demise” – burning up completely as they re-enter the atmosphere. Sounds good on paper, right? The problem is, the physics of this re-entry process aren’t fully understood. We simply don’t know how much material truly vaporizes and how much makes it to the ground. Richard Ocaya, a physics professor and coauthor of a paper on space debris risk, states it plainly: “The number of such landfall events is increasing… We expect it may be increasing exponentially in the next few years.”
Designed for Demise? Not Always.
Companies like SpaceX, with its vast Starlink mega-constellation, often claim their satellites are “designed for demise,” meant to disintegrate entirely. However, not everyone agrees. James Beck, director of UK-based Belstead Research, has conducted wind tunnel tests on satellite mock-ups, mimicking the immense atmospheric forces of re-entry. His findings raise serious doubts.
Beck points out that some satellite components are made from incredibly durable materials like titanium and special alloy composites. These don’t melt away even at the extreme temperatures generated during a hypersonic descent. “For larger satellites, around 800 kilos, we would expect maybe two or three objects to land,” he explains. So, while a satellite might largely burn up, critical, dense pieces can still survive the fiery plunge.
Beyond Wild Speculation: Quantifying the Risk
It’s easy to get lost in the dramatic headlines, but what are the actual chances of something happening? Quantifying the danger posed by space debris is notoriously difficult. The International Civil Aviation Organization (ICAO) has acknowledged that “the rapid growth in satellite deployments presents a novel challenge” for aviation safety, one that “cannot be quantified with the same precision as more established hazards.”
However, the Federal Aviation Administration (FAA) has been crunching some preliminary numbers. In a 2023 analysis, they estimated that by 2035, the risk of one plane per year experiencing a “disastrous” space debris strike would be around 7 in 10,000. A disastrous collision, in this context, means the aircraft would either be destroyed immediately or suffer a rapid loss of air pressure, imperiling everyone on board.
Closer Calls on Solid Ground
While an aerial collision remains a rare event, the risk to humans on the ground is projected to be significantly higher. Aaron Boley, an associate professor in astronomy and a space debris researcher, warns that if megaconstellation satellites “don’t demise entirely,” the risk of a single human death or injury caused by space debris on the ground could reach around 10% per year by 2035. That implies a better than even chance that someone on Earth would be hit by space junk about once every decade.
The FAA, with similar assumptions, puts the ground risk even higher: “one person on the planet would be expected to be injured or killed every two years.” We’ve already seen close calls that underscore this. In March last year, a 0.7-kilogram chunk of metal, later confirmed as a remnant from a battery pallet jettisoned by the International Space Station, pierced the roof of a house in Florida. The homeowner’s 19-year-old son was in an adjacent room. Just imagine.
Other incidents include a 1.5-meter fragment of a SpaceX Falcon 9 rocket crashing near a warehouse in Poland, and a 2.5-kilogram piece of a Starlink satellite landing on a farm in Canada. Incidents have also been reported in Australia and Africa. And, as James Beck notes, many more likely go completely unnoticed. “If you were to find a bunch of burnt electronics in a forest somewhere, your first thought is not that it came from a spaceship,” he points out, highlighting our potential blind spot for this burgeoning problem.
Navigating the Unknown: The Challenges Ahead
Given these growing risks, experts are understandably exploring how to integrate space debris into existing air safety protocols. Companies like Okapi Orbits are working with organizations like the German Aerospace Center and Eurocontrol to adapt air traffic control systems. The goal? To provide pilots and controllers with timely, accurate alerts about potential space debris threats. But this is far easier said than done.
Predicting the exact path of re-entering space debris is incredibly challenging. While AI has improved trajectory predictions in the vacuum of space, these algorithms currently struggle to account for the complex effects of the atmosphere as junk spirals downwards. Radar and telescope observations help, but they provide precise impact locations only with very short notice. As Njord Eggen, a data analyst at Okapi Orbits, explains, “Even with high-fidelity models, there’s so many variables at play that having a very accurate reentry location is difficult.” Given that objects in low Earth orbit circle the planet every hour and a half, even “uncertainties on the order of 10 minutes” can have “drastic consequences” for impact location.
More Than Just a Direct Hit: The Cost of Caution
For aviation, the problem isn’t just the catastrophic potential of a direct strike. To avoid accidents, authorities are increasingly likely to temporarily close airspace in at-risk regions. These closures, even if precautionary, translate directly into delays and significant costs. Boley and his colleagues published a paper estimating that busy aerospace regions, such as northern Europe or the northeastern United States, already face about a 26% yearly chance of at least one disruption due to the re-entry of a major space debris item.
Think about that. By the time all planned satellite constellations are fully deployed, airspace closures due to space debris could become almost as common as those caused by bad weather. And, as the incident with the 21-metric-ton Chinese Long March rocket in 2022 showed, many of these closures might end up being unnecessary. Its debris was predicted to scatter across Spain and France, leading to a 30-minute closure of southern European airspace and delaying hundreds of flights. The rocket ultimately crashed harmlessly into the Pacific Ocean. Imagine the frustration and economic impact if this becomes a regular occurrence.
What’s Being Done, and What’s Still Circling?
In the face of these challenges, international regulators are pushing satellite operators and launch providers to deorbit large satellites and rocket bodies in a controlled manner whenever possible. This involves using any remaining fuel to guide them precisely into remote parts of the ocean. However, the European Space Agency estimates that only about half the rocket bodies re-entering the atmosphere currently do so in a controlled way.
Adding another layer of complexity, around 2,300 old, no-longer-controllable rocket bodies still linger in orbit. These unguided behemoths are slowly but surely spiraling towards Earth with no mechanism for operators to safely steer them. “There’s enough material up there that even if we change our practices, we will still have all those rocket bodies eventually reenter,” Boley warns. He drives home a critical point: “Although the probability of space debris hitting an aircraft is small, the probability that the debris will spread and fall over busy airspace is not small. That’s actually quite likely.”
Flying into the Future: Navigating a More Cluttered Sky
So, what’s the chance your plane will be hit by space debris? For now, it’s still incredibly small – far less likely than, say, being struck by lightning. But that probability is unequivocally growing, not just for direct hits but also for the disruptions and uncertainties that come with a sky increasingly littered with our past ventures into space. The challenge isn’t just about preventing a catastrophic collision, but about intelligently managing a complex, ever-changing aerial environment.
As we continue to launch ambitious constellations, it’s clear that the responsibility extends beyond simply reaching orbit. It encompasses the entire lifecycle of these objects, right down to their fiery, uncertain demise. For those of us looking up, or flying through, the conversation about what goes up must now definitively include what comes down.
