Our recklessness in space risks life and limb on Earth
By Moriba Jah|September 2024
In the “Chicken Little” folktale, the main character infamously claims, “The sky is falling.” His evidence turns out to be shoddy — an acorn has landed on his head. I feel empathy with poor Chicken Little, but I’m nothing like him. In fact, no one who sounds the alarm over the threat of space debris is. The sky, in a sense, really is falling, and humanity’s reckless satellite and rocket operations are to blame. This isn’t science fiction; it’s a looming disaster with tangible, potentially deadly consequences.
Let’s look at some of the evidence.
In May, near Asheville, North Carolina, an employee of a mountaintop camping resort found a strange, charred object on the grounds. It was part of the storage trunk from a SpaceX Dragon capsule. In March, a munition-looking cylinder pierced the roof of a family home in Naples, Florida. It was part of a structure tossed overboard from the International Space Station three years earlier with 2.6 metric tons of trash. These were relatively small items, but it doesn’t stop there. In December, a Chinese rocket body the size of a school bus narrowly avoided landing in a populated area. In 2023, a large cylindrical object was found on an Australian beach. It “most likely” came from an Indian rocket launch, the Australian Space Agency said on X. In 2022, another strange object, this one 3 meters tall, was found sticking pointy end first into the ground of an Australian farm. It was part of another Dragon trunk, this one discarded during the return of the Crew-1 astronauts in 2021.
I could go on, but you see the point. Our modus operandi for how we perform space activities is such that our calculated risk involves being OK with uncontrolled space object trajectories. In other words, China is OK with school-bus-sized objects landing on populated areas, and the world writ large is OK with dead things in orbit coming back to Earth in whichever manner Mother Nature deems fit. Each of these objects that makes it to the surface, whether it be during launch or atmospheric reentry, is like a ticking time bomb: The only question is whether it will hit someone or perhaps something, such as an airliner full of people.
So far, we’ve been lucky — and by lucky, I mean that human-driven inputs into the conditions of the complex system we know as life have not yet resulted in a catastrophe. There are no documented cases of someone being killed or severely injured by space debris. Eventually, because of human activities absent due regard, luck will run out.
As the examples above show, space is a shared environment, and actions by one nation can have catastrophic consequences virtually anywhere. NASA knows this. Before approving the release of trash, the models used by the Orbital Debris Program Office are evaluated for an expected casualty probability. If this threshold is less than 1 in 10,000, the assumption is that the risk is acceptable.
The agency has begun to acknowledge that its models are flawed. “During its initial design, the Dragon spacecraft trunk was evaluated for re-entry breakup and was predicted to burn up fully,” NASA is quoted saying in numerous publications following the incident in North Carolina. “The information from the debris recovery provides an opportunity for teams to improve debris modeling.”
As for SpaceX, the company in July announced several changes to its deorbiting procedures, including waiting to jettison the trunk until after Dragon completes the 12-minute deorbit burn through the atmosphere.
That’s a positive change, because by my review of media reports and SpaceX and NASA statements, the North Carolina incident makes at least five cases in which the trunk of Dragon missions has reached Earth’s surface intact. These incidents reveal that our current debris mitigation strategies and reentry demisability prediction models are inadequate; the risk to human life is greater than previously believed.
Those who downplay the risk of debris colliding with property and people on the ground have weak cases. Carl Sagan was one of several people who paraphrasingly said, “Absence of evidence is not evidence of absence.” This is to say, just because there is no evidence of a significant threat to people from falling space objects doesn’t mean that the threat is indeed insignificant. Expected casualty estimates are based on Bayesian probabilities, which are inherently subjective. When space operators are uncertain, they inflate the volume of the covariance matrix to reflect their uncertainty. This causes the probability of a casualty or impact with someone or something on the ground to tend toward zero — a phenomenon known as the probability dilution problem. This approach defies common sense. Ignorance should not equate to lower risk.
In contrast, a frequentist approach based on empirical evidence shows that the risk is increasing. As global satellite launches surge, so too does the frequency of people encountering falling objects on their property. The evidence is clear: The threat is real and growing.
Sadly, at the moment, few are taking this problem seriously. NASA deliberately releases about 2.5 tons of junk from ISS each year. Although most of this by and large incinerates in the atmosphere, such uncontrolled reentry is not a responsible disposal method. It’s abandonment, hoping that the atmosphere will take care of the problem. This approach is akin to dumping manufacturing waste into a river, hoping it will decompose over time. The Cuyahoga River caught fire multiple times before we took action.
The United Nations’ Liability Convention is clear: Launching states are liable for any damage caused by their space objects. Yet, accountability is often murky. The rapid pace of satellite launches and the increasing volume of space debris demand a collective international response. We need stricter enforcement of existing treaties, improved tracking and prediction of falling debris, and robust mitigation strategies. Additionally, we must invest in technologies to safely deorbit defunct satellites and other objects. The liability framework must hold all parties involved in a launch accountable, including those procuring the launches and hosting facilities.
The evidence is undeniable, and the warnings are clear. We cannot afford to dismiss the threat of falling space debris as alarmism. It is a real, present danger, exacerbated by our growing dependence on space-based technologies and the increasing volume of launches. The sky is falling, and it is our responsibility to prevent the loss of life. As stewards of space, we must act now to protect our planet and its inhabitants from the dangers of our own making.
