Why Russia (Probably) Won’t Crash the Space Station

Ukraine is not the only theater of conflict in the current war between Russia and the former Soviet republic. The 30 nations of NATO are coordinating sanctions, sending supplies, and moving troops and weaponry into position to defend the alliance from a wider war. All 193 member countries of the United Nations are involved too, as the U.N. scheduled an emergency meeting of the General Assembly—only the eleventh such crisis gathering since 1950—to try to bring the war to an end.

And the repercussions of Russia’s invasion are being felt still farther away—400 km (248 mi.) overhead, aboard the International Space Station (ISS). The station is a collaborative facility built and maintained by 15 different nations, with the U.S. and Russia as the leading partners. The station is made up of 16 habitable modules, six of which were provided by Russia, eight by the U.S., and the remainder by Japan and the European Space Agency. One European and four American astronauts are currently aboard, along with two Russian cosmonauts.

The question of how the space station might be affected by the war was largely a tangential issue—until, that is, Dmitry Rogozin, director of Roscosmos (Russia’s NASA) caused alarm late last week with a series of tweets in which he threatened to allow the entire football-field-sized facility to come crashing back to Earth, unless the U.S. and the rest of the West back down on sanctions imposed over the war.

“Do you want to destroy our cooperation on the ISS?” he wrote in part. “Maybe [U.S.] President Biden is off topic, so explain to him that the correction of the station’s orbit, its avoidance of dangerous rendezvous with space garbage … is produced exclusively by the engines of the Russian Progress MS cargo ships. If you block cooperation with us, who will save the ISS from an uncontrolled deorbit and fall into the United States or Europe? There is also the option of dropping a 500-ton structure to India and China. Do you want to threaten them with such a prospect? The ISS does not fly over Russia, so all the risks are yours. Are you ready for them?”

This is not the first time Rogozin has indulged in such bluster. In 2014, when Russia annexed Crimea and the West then too pushed back with sanctions, the U.S. was entirely dependent on Russia’s Soyuz spacecraft to get astronauts to the ISS—with the space shuttles having been retired three years earlier. “After analyzing the sanctions against our space industry, I suggest to the USA to bring their astronauts to the International Space Station using a trampoline,” Rogozin famously tweeted.

As it did back then, NASA is largely ignoring Rogozin’s taunt, issuing no formal statement beyond one it made in response to a query from Space.com. “NASA continues working with all our international partners, including the State Space Corporation Roscosmos, for the ongoing safe operations of the International Space Station,” the space agency wrote. “No changes are planned to the agency’s support for ongoing in orbit and ground station operations.”

Retired astronaut and former space station commander Terry Virts was equally unmoved by Rogozin’s latest outburst. “I was not surprised, based on his previous behavior,” he told TIME. “This is what I’ve come to expect.” Still, Virts did not consider Rogozin’s comments completely without menace. “On one hand, I responded with an eye roll,” he says. “On the other hand, I though, ‘He just really damaged the space station partnership.’”

How badly he damaged it is open to question. Given the pointedness of Rogozin’s tweetstorm, the big question that remains is whether the Russians really could—or would—damage or destroy the station in a fit of pique over terrestrial politics. The answer is: it’s unlikely, but not impossible.

Rogozin is right on a few points. The station’s guidance and orientation is indeed controlled by one of the Russian segments of the station—the Zvezda, or “Star,” module. What’s more, uncrewed Russian Progress cargo ships play a critical role in keeping the station flying. Even 400 km above the Earth, the ISS encounters tenuous wisps of atmosphere which would, over time, drag it back down out of orbit—like the then-unoccupied U.S. Slylab station, which crashed into the Australian outback in 1979. Periodic reboosts by the Progress engines prevent that from happening, raising the station’s orbit as needed. Refusing to fire those engines would indeed cause the station to drop out of orbit—presumably after all crewmembers from all nations had evacuated. (When the station is eventually retired as planned in 2030 or so, firing the engines in the other direction—to lower the vehicle—will send it on a controlled plunge into an ocean, likely the Pacific.)

Rogozin is right, too, that the station does not fly over Russian soil directly. American space shuttles typically orbited at an inclination of about 28º relative to the equator. That allowed the spacecraft to pass regularly over the U.S. Since the earliest days of the space program, spacecraft launched by the old Soviet Union have flown at sharper inclinations of 51.6º, ensuring that they would pass over what was then Russian territory, but is now Kazakhstan—the location of the Baikonur Cosmodrome, from where Russian spacecraft are launched. In an early concession to Moscow as part of the U.S.-Russia partnership, Washington agreed that the station would fly at the higher 51.6º inclination, making it easier for Russian Soyuz spacecraft and cosmonauts to reach it. So if the ISS fell out of the sky, Russia would indeed not be in the path of the collision—though Kazakhstan potentially would.

One recent development, however, has checked Russia’s ability to doom the station unilaterally. On Feb. 21, an uncrewed American Cygnus supply ship arrived at the station with, among other things, an engine attached that can—and will—be lit to perform a reboost from the U.S. end of the station. If Russia refused to allow Progress vehicles to do the job, this and future Cygnus craft could take it over.

That doesn’t fix the problem entirely. The station’s thrusters and guidance are still controlled by the Zvezda, and even if the Russians could not knock the station out of the sky, cosmonauts could put it into a spin that would effectively disable it, preventing the ISS solar panels from getting a proper fix on the sun. But would they?

Virts, who was aboard the station in 2015, during fighting between pro-Russian and pro-Ukrainian forces in the Donbas region of Ukraine, simply doesn’t see such a scenario unfolding, given the professionalism typical of astronauts and cosmonauts alike.

“At the time, I said, ‘Hey, guys, politics is politics. And that’s not why we’re here,’” he says. “For this crew, I’m sure they’re being very professional and working together. This is a major event on Earth. One of the crew’s nations is attacking a free democracy and so there’s tension, I’m sure, but I’m also sure that they’re handling it professionally and trying to focus on their mission.”

As for whether countermanding orders ever would come up from the ground, directing the Russian cosmonauts to disable the station, while the Americans and Europeans were told to maintain it—setting off a verbal and perhaps physical confrontation among the crew members to seize control of the station? Virts does not rule it out—but does not care to contemplate it either.

“That would be a nightmare scenario,” he says. “That would be an absolute disaster. You don’t want that conflict spilling over into space. I don’t think that’s going to happen,” he concludes, but then adds ominously: “I also didn’t think they were going to invade Ukraine.”