In the coming months, NASA will evaluate commercial proposals for vehicles capable of “decommissioning” the International Space Station – that is, safely dropping it into Earth’s atmosphere to burn up. The agency has announced that it expects to pay nearly a billion dollars for this service to avoid reliance on multiple Russian vehicles. The brutal finality is scheduled to occur early next decade, but it is already proving to be extremely sensitive in terms of aerospace engineering and international diplomacy.
Imminent Problem
The fate of the laboratory stems from its position in low Earth orbit, within the fragile upper layers of Earth’s atmosphere. There, everything that rises must descend, drawn to our planet by a constant stream of atmospheric particles that slow its speed.
Without periodic boosts, when the spacecraft in low Earth orbit loses its velocity, it also loses altitude, eventually descending low enough to break apart and burn up as it plunges into our planet’s atmosphere. Most of the boosts in orbit are to keep the space station from being continuously entangled by ongoing thralldom from Russian boats.
Theoretically, NASA and its partners could raise the space station to an orbit that completely leaves Earth’s atmosphere. But raising a very large mass to a very high altitude would be prohibitively expensive. And even if the station is abandoned in such a “graveyard orbit,” it would later pose risks: due to its age and inflexibility, its disintegration would be inevitable and produce vast amounts of debris that could damage other satellites.
If the space station cannot orbit forever, it must burn in a blaze of glory. There are two ways this can happen: either in a controlled, destructive descent through the atmosphere, or in what is called “uncontrolled descent,” where the space station would drop to the Earth’s surface at the whim of nature. While that may sound spectacular, the latter option is undoubtedly dangerous. The space station is larger than a football field, and its orbit carries it over more than 90 percent of the Earth’s population. So far, the damage caused by falling spacecraft debris has been minimal – but as the largest object ever returned to Earth, the space station could easily change that.
Downward Path
Nasa officials say the safest way to bring the space station back to Earth is to drop it in the sparsely populated Southern Pacific Ocean to reduce the chances of damage.
This is tricky because the orbital time loop of about 1.5 hours makes it traverse over 250 linear miles of Earth’s surface every minute, with a ground track that continually changes with the world’s rotation. The longer the space station spends falling through the atmosphere, the larger its debris field will be along that trajectory, increasing the chances that a flying piece could cause chaos somewhere on the surface. However, the descent should not happen too quickly: if the space station were to plunge into the atmosphere too forcefully, increasing air resistance could rip large pieces like expansive solar panels or individual modules apart, which in turn would cause them to enter the atmosphere in uncontrolled and unpredictable ways. The irregular engineering of the space station further complicates this issue, making it critical to keep the station in a stable position during its atmospheric descent. If it were to roll during its descent, the rocket controlling the descent would no longer be pointing in the right direction, dangerously sending the space station off course.
Additionally
the reality is that there are significant hurdles to overcome. “NASA has been working on a vehicle like this for many years, but it is a very complex project,” McDowell says. “It hasn’t been funded at a level that would allow for a rapid development timeline.”
Ultimately, whether it’s achieved through a partnership with Russia or through an independent U.S. solution, the return of the International Space Station to Earth will be a monumental task that requires extensive planning and coordination. As the time draws closer, all eyes will be on the teams involved to ensure a safe and controlled descent for the astonishing legacy of human endeavor in the cosmos.
If NASA wants a single landing vehicle designed based on the current global space fleet, it doesn’t have many options. “The things that seem obvious when you start thinking about them – they just don’t have the thrust to do a big final burn in a short amount of time,” says McDowell. He believes the closest existing technology is the European Service Module in the Artemis program, which provided power for NASA’s uncrewed Orion capsule during its landmark flight around the moon last fall and is scheduled to help land humans on the lunar surface later this decade. Everything else, he says, is either too weak or too powerful or simply unable to carry enough fuel for the mission – hence NASA’s requests for commercial proposals for a new vehicle designed specifically for landing.
Whether NASA opts for something new or a modified existing vehicle for the mission, the decision will impact the many other international relationships that are built around the International Space Station. The end of the space station is a shared responsibility just as much as building and maintaining it, but NASA’s public documents are unclear about whether the Canadian, Japanese, European, and Russian space agencies have signed onto the U.S.-led plan and are executing it commercially.
The end of the massive project also paves the way for a different set of international discussions about future partnerships in space. NASA is already building bilateral partnerships with countries interested in lunar exploration through Artemis accords, although Russia is not among them. China – which has been barred from participating in the International Space Station under U.S. federal law – has now become a space power, with its own space laboratory, as well as its lunar and Mars robotic missions. Whether the end of the International Space Station will lead to a détente between the U.S. and China is anyone’s guess.
What’s certain, according to political scientist Kross, is that any future international partnerships will not replicate the International Space Station, which is likely to remain a unique and shining achievement. “The landscape of nations in space looks completely different now than it did when Russia and the United States began cooperating on the International Space Station,” she says. She adds that she hopes these partnerships will be well established before the dramatic end of the space station.
Whenever the International Space Station eventually returns to Earth, its fall will be one of the most bitter events in the long and storied history of spaceflight. “There aren’t many times in history that we have the opportunity to do such a maneuver,” says Arnas. “They’re going to be really nervous on the day they have to do that.”
Copyright and permissions: Megan Bartels is a science journalist based in New York City. She joined Scientific American as a news reporter in 2023. Previously, she spent more than four years as a writer and editor at Space.com, as well as nearly a year as a science reporter at Newsweek, where she focused on space and Earth sciences. Her writings have also appeared in Audubon, Nautilus, Astronomy, Smithsonian, and other publications. She attended Georgetown University and earned her master’s degree in journalism from the science, health, and environmental reporting program at New York University.
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