The International Space Station has transcended terrestrial political troubles between the United States and Russia for more than two decades. But some former NASA astronauts who spent months floating alongside Russian cosmonauts are worried the current crisis in Ukraine could end the US-Russian partnership in space. The ISS, which is a collaboration between the US, Russia, Japan, Canada, and the European Space Agency, has so far remained insulated from the geopolitical battle brewing on Ukraine’s border, though the head of Russian space agency Roscosmos, Dmitry Rogozin, recently alluded to “cold winds that are now blowing from Washington and Brussels,” according to Russian state-owned media TASS. “It scares me that if this becomes a shooting war, I think it would be hard for the ISS to survive,” former NASA astronaut Garrett Reisman told CNN. NASA Administrator Bill Nelson is confident that the International Space Station will remain insulated from global politics, especially after the Biden administration announced in December that it is committed to extending its operations through 2030. Russia, however, still has not committed to the Biden administration’s six-year extension of the International Space Station. “The talks with NASA on extending the operation of the ISS until 2030 are underway,” Rogozin told TASS in January. “There may be political problems,” Nelson said in an interview with CNN. “But when it comes to our civilian space program and our cooperation, there has never been a problem and I expect that to continue.” When Russia occupied and subsequently annexed Crimea (a move unrecognized by the United States) in 2014, NASA Astronauts Rick Mastracchio and Steve Swanson were on board the International Space Station. They say no one in Houston’s Mission Control ever even mentioned the ongoing tensions. “Nobody talked about it. It was completely like it’s not happening,” Swanson told CNN. “We were just going about our normal business and not worrying about it.” But Mastracchio says they did discuss the political turmoil taking place roughly 250 miles below with their cosmonaut crewmates. “There was no finger pointing or accusations or who’s right or who’s wrong. It was just talking through the different points of view,” he said. But even if it were to come to a space station split, breaking up in space is easier said than done. Astronauts and cosmonauts depend on each other and their equipment while living and working in the dangerous vacuum of outer space. “The Russian segment can’t function without the electricity on the American side, and the American side can’t function without the propulsion systems that are on the Russian side,” Reisman said. “So you can’t do an amicable divorce. You can’t do a conscious uncoupling.” The complex interdependency even extends to the station’s water supply. “We actually recycle the cosmonauts’ urine to get more water for our side to drink,” Swanson said. “Now that’s transcending politics. It’s survival.” “That was always troublesome, to go ask somebody if you could borrow a tank of their urine,” Mastracchio said. It’s a type of bond that’s difficult to duplicate on Earth, and it’s part of the reason the NASA administrator describes the station as a “beacon of peaceful international scientific collaboration.” “Whenever we’ve had political trouble with the government of Russia in the past, the astronauts and the cosmonauts do not miss a beat,” Nelson said. But Russian politicians have threatened to use the station as a bargaining chip during previous geopolitical crises. When the United States imposed sanctions on Russia after the 2014 annexation of Crimea, it was entirely reliant on Russian Soyuz rockets to launch NASA astronauts to the space station and return them safely home. “After analyzing the sanctions against our space industry, I suggest the US delivers its astronauts to the ISS with a trampoline,” Rogozin, then Russia’s Deputy Prime Minister of Defense, said in a tweet at the time. Mastracchio, who was on board the station when Rogozin made those remarks, says he was “not concerned personally,” but that his family was worried “he was going to get stranded in space, because the Russians are not going to bring him home.” Rogozin’s threats never materialized, however, and the station’s operations continued uninterrupted throughout the 2014 crisis. Since then, a private American corporation has developed its own launch vehicle — SpaceX’s Falcon 9 rocket and Crew Dragon capsule — which has drastically reduced NASA’s dependency on Russia. The United States is also trying to extend this partnership in space to the moon with NASA’s new Artemis program. But so far, Russia has refused to participate, and is instead planning to team up with China. Russia’s Ambassador to China announced Tuesday that an agreement to build a base on the moon “is practically ready and it seems that it may be signed quite soon,” according to TASS. The potential agreement with China, combined with the crisis in Ukraine and Russia’s recent test of an anti-satellite missile, could be the beginning of the end of the US-Russian alliance in civilian spaceflight, which has continued uninterrupted since 1975. “Unfortunately, I do think it’s destined to end,” Reisman said. But the NASA administrator is more optimistic, describing the partnership as “one of the truly remarkable stories of our time.” “Isn’t it something that when our politics on terra firma are causing us to be at odds with each other, us earthlings can overcome that around a common civilian space program and cooperate so beautifully,” Nelson said.