ARI SHAPIRO, HOST:
NASA and Russian space managers are scrambling to understand the cause of a major leak at the International Space Station. Yesterday, a Russian capsule docked to the station spewed coolant uncontrollably for hours. While NASA says the crew is safe for now, the incident raises questions about the safety of the seven people on board. From member station WMFE, Brendan Byrne explains.
BRENDAN BYRNE, BYLINE: Russian cosmonauts Sergey Prokopyev and Dmitri Petelin in were inside the station's airlock, about to begin a spacewalk, but then warnings that the Soyuz capsule was jetting liquid into space.
UNIDENTIFIED PERSON: The cause of that leak of coolant, not known at this point, the effect, not yet known at this point.
BYRNE: Ground teams canceled the spacewalk. While the crew was safe, the sight of a leaking spacecraft was unsettling, says Terry Virts, a retired NASA astronaut who flew to the station in a Soyuz capsule in 2014.
TERRY VIRTS: When you see it leaking fluid like that, you know something very, very bad is happening.
BYRNE: That Soyuz spacecraft transported the cosmonauts and a NASA astronaut to the ISS in September. It's their planned ride home in March. But in the short term, Marsha Smith with SpacePolicyOnline says it's also a key piece of safety hardware like a lifeboat.
MARCIA SMITH: So you have to have a way to get off the space station if there's an emergency.
BYRNE: It's unknown if they'll be able to use this capsule to eventually return to Earth. Russia may need to launch an uncrewed replacement vehicle.
SMITH: There has been pretty much an ironclad rule since the space station got up there that you can only have as many people on board the space station at any one time as you have lifeboats to get them off.
BYRNE: There are four other astronauts on the ISS that arrived in SpaceX's Crew Dragon capsule, which was unaffected by the coolant leak and can still serve as a lifeboat for that crew. But as NASA and Russia's space agency work to resolve the issue, retired astronaut Terry Virts is urging caution. When investigating a leak on another Soyuz spacecraft in 2018, Russia blamed NASA astronauts and even alleged sabotage by a U.S. crew member. The origin of that leak was never revealed. And with the Russia war in Ukraine, diplomatic tensions remain high.
VIRTS: So I really hope they do the right thing. But I think we should not be putting ourselves in this position where we have to depend on them to do the right thing. And so it's a serious problem on a technical level and also on a much-bigger-picture level also.
BYRNE: And that spacewalk, which has been delayed twice, will have to wait as teams on the ground and at the station work to figure out what caused the leak in the first place. For NPR News, I'm Brendan Byrne in Orlando. Transcript provided by NPR, Copyright NPR.