The astronauts were still asleep when NASA called the International Space Station. “Hey, Mark, good morning. Sorry for the early call,” a mission controller said in the early hours of Monday morning, speaking with Mark Vande Hei, one of four NASA astronauts on board. But the astronauts needed to get up, mission control said calmly, and move to the spacecraft docked to the station. They needed to be prepared to potentially escape and head back to Earth. This was an emergency.
NASA had just received word that a satellite had shattered into pieces. The cloud of debris was about to pass dangerously close to the space station, and everyone on board—four American astronauts, two Russian cosmonauts, and one German astronaut—had to hunker down.
The satellite, it turned out, was a Soviet machine from the 1980s. Russia had decided to blow it up in a test of the country’s anti-satellite technology. When the missile strike destroyed the satellite, the impact produced more than 1,500 fragments large enough to be tracked with military resources, and likely hundreds of thousands more too small to detect.
When something breaks this high up in space, the shards don’t just sit around. Like the ISS, the cloud of space junk loops around Earth. And the space station, officials realized, intersected with the orbit of that junk every 90 minutes. Remember that scene in Gravity where space debris pummels Sandra Bullock and her fellow astronauts while they’re working on the Hubble Space Telescope? That was a worst-case representation of what can happen when the orbit of spacefarers and the orbit of space junk overlap.
The ISS crew floated into their transport capsules around 2 a.m. eastern and didn’t emerge for about two hours, according to NASA. Although the debris continued to zoom past them after that, experts at NASA determined that the astronauts could relax a bit. “The chances of losing ISS are small,” Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics who is well known in the space community for his expert monitoring of low-Earth orbit, told me. “The chances of a minor debris hit may be large”—a piece of debris might slice a hole in one of the space station’s solar panels, for instance. Not great, but not catastrophic either. Phew.
On Tuesday afternoon, mission control in Houston was still warning astronauts about upcoming passes of the debris cloud. But the crew seemed to be taking the situation in stride. Let us know if things are getting worse, Vande Hei told mission control yesterday, but otherwise “we’ll go on with the day.” Today, the live feed for ISS communications is a hum of business-as-usual. They’re fine.
But what about, you know, space? Particularly the part where all of this junk is now hurtling around. Is everything okay up there?
The space experts I spoke with all characterized this week’s situation as, well, bad. No one wants “a debris-generating event in outer space,” as U.S. officials put it on Monday. Close passes between satellites can happen, and they’ve become more common in recent years. Two years ago, for example, a European Space Agency satellite was forced to dodge a SpaceX internet satellite. Everyone has to simply watch their own flank: Without an international system monitoring satellite traffic, satellite providers are stuck literally emailing each other when they anticipate an uncomfortably close pass. In some cases, reaching out is a challenge. Bill Gerstenmaier, a vice president at SpaceX, said at an industry conference yesterday that while SpaceX notifies the ISS about any close approaches of its internet satellites, the company isn’t sure how to contact Tiangong, the Chinese space station, which currently has a crew of three.
Sure, space is big, but low-Earth orbit, where the ISS and many satellites reside, is not as spacious as we might think. The space above us is, remarkably, a finite resource, with a theoretical limit to how much it can hold. The concept is called “orbital carrying capacity.” Specific parameters have not been formally defined, but the basic idea is that someday we could exceed this capacity when certain bands of orbit become so crowded with new and defunct satellites that they become difficult to navigate. For now, orbital carrying capacity might sound like a joke about carry-on restrictions for outer space, but as more companies launch satellites—not just one or two, but whole “mega-constellations,” as they’re called—the question is becoming a real concern.
Anti-satellite tests only make the situation worse. Russia, the United States, China, and India have all carried out such tests. The most recent display, by India in 2019, produced hundreds of pieces of debris, but at a low-enough altitude that nearly all of the junk eventually plunged into Earth’s atmosphere and disintegrated. But debris from tests like the one Russia just carried out can stick around. The collision risk for objects in low-Earth orbit, McDowell said, has now increased “for the next few months and probably years.” Just last week, the ISS had to shift itself to avoid colliding with a piece of debris from a Chinese test in 2007.
What makes the latest test particularly unnerving is that Russia shares the ISS with the United States. American astronauts and Russian cosmonauts worked together to build the station, piece by piece, in orbit. The two countries have plenty of Earth-bound disagreements, but the space station is supposed to remain above them, literally and figuratively. And then here comes Russia, blowing up a satellite and forcing astronauts into their emergency procedures.
U.S. defense officials have criticized the Russian test as “reckless and irresponsible.” NASA Administrator Bill Nelson said in a statement, “It is unthinkable that Russia would endanger not only the American and international partner astronauts on the ISS, but also their own cosmonauts.” Russian officials have denied accusations that the test threatened the space-station crew, and Dmitry Rogozin, the head of Roscosmos, the Russian space agency, tweeted yesterday that he had spoken with Nelson by phone and they’re working together to move forward.
There aren’t really rules for navigating this awkward situation. An international treaty for outer space exists, but it has no penalties for using space weapons such as anti-satellite missiles. “There is no internationally agreed-upon set of behaviors that we can point to when someone does something that could be potentially harmful,” Victoria Samson, a military-space expert at the Secure World Foundation, an organization that focuses on issues of space sustainability, told me. And despite strong words from U.S. officials about the latest Russian test, the American government has been reluctant to lobby for strong regulations, because the country has anti-satellite weapons of its own. Right now, anyone can, in theory, blow something up in space and produce plumes of debris that threaten anyone else who happens to be up there. “It is a very bad trend to make it acceptable to deliberately create large amounts of debris on orbit, because that debris is agnostic as to who or what it hits,” Samson said.
A day like Monday can make us see the International Space Station—any space station—for what it truly is. When everything is fine, the ISS can seem almost cozy, like a big house where astronauts live and work and sleep. When something is off, the ISS suddenly becomes a fragile metal tube of breathable air suspended in nothingness. Even on a normal day, the space station is a place where, as Leland Melvin, a retired NASA astronaut, once put it to me, “you know that if Yuri does something wrong, or I do something wrong, or Peggy does something wrong, we can all die.”
On Monday, when the crew was roused from its sleeping bags, three of the American astronauts and the German astronaut took shelter in the SpaceX spacecraft that had delivered them to the station just days earlier. Vande Hei, the fourth American, sheltered with the two Russian cosmonauts in a Russian Soyuz spacecraft that had arrived in April. Astronauts and officials alike have said many times in the past that the ISS has managed to weather all kinds of geopolitical kerfuffles, including the Crimea invasion and election meddling. But the latest situation is different. How do you tiptoe around the topic of one of your officemate’s bosses blowing a satellite to bits, with seemingly no regard for their safety—or yours?