One Satellite Crash Could Upend Modern Life
The Big One in orbit might take many forms. All of them could be disastrous.
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Updated at 5:03 p.m. ET on June 14, 2024
Earlier this year, two satellites from two adversarial countries nearly collided while orbiting Earth at thousands of miles an hour. The first, an American spacecraft on a NASA mission to study the planet’s upper atmosphere, wasn’t built to maneuver in orbit. The second, a Russian surveillance spacecraft, was defunct, and thus uncontrollable. The only thing people on Earth could do was watch. Darren McKnight, a space-debris expert, stayed up all night on February 28, monitoring the trajectories of the satellites, which, combined, weighed several thousand pounds. “I felt very, very helpless,” McKnight told me.
According to LeoLabs, the U.S. space-tracking firm where McKnight works, the probability of collision that night was somewhere between 3 and 8 percent. That may not seem so terrible, but risk works a bit differently in the realm above Earth. Satellite trackers like McKnight start sounding the alarm when the probability of a crash reaches 0.001 percent; no one wants to see whole-number or, God forbid, double-digit percentages. In the end, the research spacecraft and the spy satellite ended up passing within just 33 feet of each other. At a recent conference, Pam Melroy, NASA’s deputy administrator, said the near miss was “very shocking” and “really scared us.”
A collision between the two satellites would have unleashed thousands of debris fragments into low Earth orbit, an already congested region of space where close passes are becoming more common. Numerous debris-generating events, as experts call them, have transpired over the past several decades. So far we’ve avoided a significant disaster through a combination of maneuvering and luck, but government agencies and companies have begun to recognize that the status quo is unsustainable, and to invest in efforts to manage the messiness.
The threat of a disastrous event is always lurking in low Earth orbit, frustratingly unpredictable but worryingly persistent. It’s not unlike the major earthquake that is expected to rock California in the coming decades. In the orbital landscape, the “Big One” could come in the form of any number of scenarios: collisions between satellites, the intentional shooting-down of a spacecraft, a nuclear event. But the outcome of such a seismic event in orbit is the same. A tremendous burst of fast-moving shards, indiscriminate in their destruction, will whiz through Earth’s jam-packed coating of satellites, threatening to tip the world below into a new reality.
A “Big One” in space would be a strangely quiet event. We would not see the swaying of the infrastructure that makes so much of our modern life possible; instead disaster would manifest right in the palms of our hands as our smartphones suddenly struggled to work. Satellite technology provides communications, GPS, and even an accounting of time to people, businesses, and governments around the world. If it fails, power grids, agricultural functions, shipping routes, and banking transactions could quickly falter too. New missions to restore technological normalcy would launch into a more perilous environment, one that may be too dangerous for astronauts to traverse. In the worst-case scenario, a hypothetical phenomenon called Kessler syndrome, space could become so overpopulated that collisions lead to a cascade of even more collisions, rendering low Earth orbit nearly impossible to navigate.
The fact that we’ve managed to fill space—space!—with so much junk can be hard to fathom. Space is, after all, enormous. But “it’s getting smaller every day,” John Crassidis, a mechanical- and aerospace-engineering professor at the University at Buffalo, told me. Satellites deployed today join broken ones that launched decades ago. Low Earth orbit, which tops out at about 1,200 miles above the ground, is also littered with discarded rocket hardware, which can generate more shards when their propellant tanks or batteries explode. Some dead satellites and pieces of debris eventually fall out of orbit, tugged downward by atmospheric drag, but others are likely to stick around for centuries.
The U.S. military is aware of more than 25,000 objects in low Earth orbit that are larger than a doughnut; the tiniest fragments, estimated to number in the hundreds of thousands, are too small to track. The International Space Station dodges potentially hazardous pieces of metal about once a year, adjusting its orbit slightly to avoid, say, a Japanese rocket part or the debris from a Chinese anti-satellite test. Higher altitudes are less crowded, but they lack the atmospheric drag that would help dispose of newly created shards. And the amount of junk there is only growing.
McKnight is particularly worried about what he calls “bad neighborhoods.” One is a cluster of rocket bodies, each the size of a school bus and weighing roughly 20,000 pounds, that have been flying past one another since the early 1990s. The probability of a collision there in the next five years is about 6 percent, and what a crash it would be: “If two of those were to collide, it would create on the order of 15,000 to 20,000 trackable fragments that would be lethal if they hit any other satellites,” McKnight said. The current record holder, a ballistic-missile test that China conducted against one of its own weather satellites in 2007, produced only about 3,600 trackable shards.
Another cluster, made up of much smaller Soviet-era hardware, has a 24 percent chance of experiencing a collision by 2029. These objects are much smaller, so a crash would create only about 5,000 fragments, McKnight said. But a debris-generating event doesn’t need to involve massive objects to create havoc. In 2021, a Russian weapons test that created just 1,500 pieces of debris still forced the residents of the International Space Station to shelter in place. A tiny piece of fast-moving debris can chip a window on the ISS. A sizable fragment could tear through the station.
The growing concerns over orbital debris have sprouted a new crop of space companies focused on its removal. Astroscale, a Japanese company, has already conducted an in-orbit demonstration, sidling up to spacecraft targeted for disposal. But debris-removing technology may prove too expensive to scale; even the tiniest maneuvers require significant amounts of fuel.
A deep clean isn’t the solution, anyway. “We cannot collect all the pieces and bring them back down,” Carolin Frueh, an aerospace-engineering professor at Purdue University, told me. Instead, the world needs to agree on how much more mess to make. In the U.S., a new rule will soon require satellite operators to safely dispose of their spacecraft no more than five years after the end of their mission. (Last year, a Colorado-based TV provider was fined $150,000 for failing to properly deorbit an aging satellite—a very small penalty, but historic nonetheless.) Another rule meant to curtail the growth of abandoned rocket hardware is on the table.
Older space powers such as the U.S. may be ready to reckon with the dangers of stranded rocket hardware, but China, coming into its own as a superpower, has left more rocket parts in orbit in the past 20 years than the rest of the world combined, McKnight said. And it doesn’t seem likely to change course anytime soon. Much news is made out of SpaceX’s thousands of internet satellites, but the company has proved itself to be a fairly responsible driver, McKnight said, conducting thousands of maneuvers to swerve out of the way of other spacecraft and debris. By contrast, the Chinese government, which has ambitious “megaconstellation” plans, is “absolutely ignoring best practices for space-traffic coordination,” he said.
Countries such as Russia, China, and India have not supported recent UN measures to halt anti-satellite demonstrations or forbid nuclear weapons in orbit. The latter could conjure hundreds of thousands of debris pieces, and might lead to “a mass extinction event for satellites,” Jessica West, a senior researcher at Project Ploughshares, a Canadian nuclear-disarmament institute, told me.
Recently, space powers and companies have begun to borrow language from another slow-moving crisis: climate change. SpaceX and other satellite operators say they’re committed to “space sustainability”; dozens of governments recently signed an agreement to become “debris neutral” by 2030. And managing space debris, like managing climate change, might require people to adapt in significant ways. We can live without space tourism and smartphones, if it comes to that. But such a change would indicate a civilizational shift, a turn inward that humans might not have imagined when we first set out into space. In the 20th century, the mark of our triumph as a spacefaring species was the constant stream of human inventions sailing beyond the atmosphere. In this century, that triumph will consist of figuring out how to avoid trapping ourselves on the ground.
Due to an editing error, this article originally misstated the speed of objects in low Earth orbit. Additionally, the article has been updated to clarify the statement that Russia, China, and India have not supported UN measures to halt anti-satellite demonstrations or forbid nuclear weapons in orbit.