WASHINGTON — Air leaks in a Russian module of the International Space Station prompted NASA to direct five astronauts to take shelter in a docked SpaceX Crew Dragon spacecraft on Friday as Russian cosmonauts prepared for repair work.
The incident occurred in the transfer tunnel, known as the PrK, of Russia's Zvezda service module. Roscosmos detected an increase in the leak rate during cargo operations the week of June 1, according to NASA.
NASA directed the four members of SpaceX Crew-12 — Commander Jessica Meir, Pilot Jack Hathaway, ESA astronaut Sophie Adenot and Roscosmos cosmonaut Andrey Fedyaev — along with NASA astronaut Chris Williams to assume a safe-haven posture in the Dragon spacecraft out of an abundance of caution.
The leaks, first identified in 2019, had been relatively minor in recent months but escalated from about one pound of air per day to two pounds, NASA officials said. Roscosmos identified new suspected leak areas and planned a more extensive inspection and structural repair.
"Following new leaks, Roscosmos has elected to proceed with a more extensive repair operation on Friday, June 5," NASA spokesperson Bethany Stevens said in a statement.
Roscosmos reported detecting two leak sites during pressurization tests. Specialists sealed one site with a two-component sealant, while work continued on the second potential location in the conical portion of the transfer chamber, the Russian space agency said via state media.
The safe-haven procedure lasted approximately two hours. Roscosmos later paused the structural repair efforts to conduct additional measurements and data assessments, including inspections of suspected areas and previously applied sealants.
NASA supported the decision to pause, and the crew members returned to normal operations aboard the station. The agency emphasized ongoing collaboration with Roscosmos on addressing the leaks.
The Zvezda module's transfer tunnel has experienced cracks leading to small atmosphere leaks for several years, prompting continuous monitoring and mitigation efforts by Roscosmos, with NASA involvement in identifying root causes.
As of Monday, no further immediate safety measures were reported, and the station's crew of seven continued planned activities. Details on the timeline for any resumed repair work remain unclear.
The International Space Station, a joint project involving multiple international partners, continues to operate with the leaks described as manageable but under close watch by mission controllers on the ground.
