Mission control in Houston first noticed it Thursday morning.
The International Space Station was drifting. The station is always moving, of course, in a looping trajectory around Earth. But this, what mission control was seeing in the latest data, was unexpected, and unnerving. On Thursday morning, the space station was suddenly and mysteriously deviating from its course.
The massive pieces of NASA-built hardware that hold the space station in place couldn’t keep up with the motion, and within minutes, the station had been thrown out of its usual orientation.
NASA quickly turned to Roscosmos, Russia’s space agency. To counter the shift, Moscow’s mission control commanded one of its modules on the space station to ignite its engines, then instructed a cargo ship to fire its thrusters too. Inside the station, astronauts reconfigured important systems. Twice, ground control lost communications with the crew for several minutes. The longer the space station remained off track, the more scrambled its operations, including the communication system and solar panels, could become.
It took about an hour to drag the ISS back into its proper configuration, and regain what its operators call attitude control. The source of the disruption was another Russian module, which had just arrived at the station. The module, a laboratory named Nauka, the Russian word for “science,” had already had a rough journey, punctuated by propulsion and communications issues, with Russian engineers rushing to put it in the right orbit. Several hours after it docked, the module, reacting to a software glitch, started firing its thrusters uncontrollably, jostling the space station. When Nauka went rogue, and Moscow instructed hardware on the other side of the station to respond, the ISS found itself in what a NASA mission-control operator called “a tug of war.”
Seven astronauts were on board at the time—three American, two Russian, one French, and one Japanese. NASA later told reporters that the astronauts hadn’t felt any shaking or movement, and officials tried to assure the public that the crew was safe. “There was no immediate danger at any time to the crew,” Joel Montalbano, the ISS program manager at NASA, said in a press conference. “Obviously, when you have a loss of attitude control, that’s something you want to address right away, but the crew was never in any immediate emergency or anything like that.”
Montalbano and other NASA officials stressed that the agency’s workers are prepared for all kinds of emergencies, and that they weren’t worried, because they hadn’t exhausted their contingency plans. But this shake-up was an uncommon event; the station has experienced inadvertent thruster firings, such as Nauka’s, maybe only three or four times in its 20-year history. And even if they’re resolved quickly, without real incident, they’re inevitably unsettling. “In my experience, people in space are always in danger,” tweeted Wayne Hale, a former flight director and manager at NASA’s space-shuttle program, which experienced two fatal accidents that claimed the lives of a total of 14 people.
The Nauka scare called to mind an incident that occured in 2018, when mission controllers noticed that the space station’s air pressure had started dropping slightly, a sign of a tiny leak. In that case, the crew was asleep. Officials decided that the pressure change was small enough that it didn’t warrant waking the astronauts. In the morning, the crew scoured the station and found a tiny hole in a Soyuz capsule, a Russian astronaut vehicle. Officials said the crew was never in serious danger, but no one wants a leak of any kind on the ISS, and the hole was quickly plugged up. Russian cosmonauts eventually conducted a spacewalk to examine the hole from the exterior, but to this day, Roscosmos won’t say how it got there.
So many aspects of spaceflight are autonomous now, including the cargo ships that dock to the ISS and the capsule that recently took Jeff Bezos to the edge of space and back. Blue Origin passengers don’t have to fly the capsule as astronauts have in the past. Neither do SpaceX passengers, who go well beyond the edge of space and all the way into orbit; last year, when two NASA astronauts test-drove a SpaceX capsule to the ISS, they flew on autopilot, taking control of the vehicle for only a few minutes, just to see how it handled. (At the time, Russian officials were the ones worried that SpaceX’s new flight software could malfunction and shove the capsule at the station.) But even today, spaceflight is far from routine, and not as smooth as recent feats have made it seem. Yes, two billionaires have flown to space in less than a month, and yes, they made it look easy. But space travel, by professional astronauts and tourists alike, remains dangerous. The futures that Bezos and Elon Musk sometimes imagine—of human beings living in artificial-gravity stations around Earth, or in an outpost on the moon, or in a glass dome on Mars—are fragile in that way.
The ISS is one of the most impressive engineering feats in history, assembled in orbit piece by piece by astronauts with the nerve to handle a tool kit while floating in space. The station was not meant to last forever, and someday, after some difficult decisions by the agencies that run it, it will be deemed too expensive or too old, and, like other stations before it, will likely be retired into the depths of Earth’s oceans. In its two decades, the ISS has served as more than a workplace or a laboratory for its rotating crews of spacefarers. It is also a home; astronauts share cleaning chores, celebrate holidays together, even binge-watch TV shows like the rest of us. I imagine that, after a few months of ISS life, astronauts are so used to floating that they drift off to sleep as easily as they would in bed on Earth. But in an instant—in the sudden rogue firing of a module—astronauts can be jolted back to the reality of what the ISS is, a metal tube traveling at 17,500 miles an hour, far beyond the reach of Earth’s protective, life-giving atmosphere. Future space travelers, whether they journey to the edge of space or another world, can’t lose sight of that, no matter how lovely the view outside the window is.