Nasa briefly orders ISS crew to shelter as air leak worsens on Russian module

WASHINGTON: A rise in an air leak aboard the International Space Station prompted Nasa on Friday to briefly direct five astronauts to take shelter and prepare for a possible evacuation while Russia worked on a crack in its section of the orbiting outpost, according to Nasa.

Nasa spokesperson Bethany Stevens said mission control ordered the four members of the agency’s Crew-12 mission — two Americans, a French astronaut and a Russian cosmonaut — along with another US astronaut, at 9:04am ET (1304 GMT), to move into the SpaceX Crew Dragon spacecraft attached to the station. Roughly two hours later, Nasa withdrew the instruction and told the astronauts they could return to the station as US and Russian officials reviewed the leak rate.

The issue centres on small but persistent air leaks in Russia’s Zvezda service module, one of the main structures of the ISS. Nasa and Russia’s Roscosmos, the station’s two leading operators, have for months differed over what caused the leaks and how best to address them.

Leak rate rose as repair work began

Roscosmos said its specialists had identified two leaks aboard the ISS and that the crew was not facing any immediate danger. The first leak had been sealed quickly and work was under way to close the second, adding that the spacecraft’s systems were not under threat.

According to a senior Nasa official who was not named, the leak had been relatively limited in recent months but increased on Friday from one pound of air per day to two pounds. The same official said cosmonauts Sergey Kud-Sverchkov and Sergei Mikayev, who did not take part in the safe-haven procedure, had planned to use a saw to open an area where they believed the crack could be reached. The official said Nasa objected to that approach, leading mission control in Houston to initiate the safe-haven order.

Stevens said Nasa lifted the precautionary order after Roscosmos halted its repair attempt. She said the agency wanted to continue discussions with its Russian counterpart on the matter.

“We look forward to working with Roscosmos on a collaborative approach to address the leaks,” she said.

Crew members remain aboard the station

The ISS currently has seven astronauts on board from two missions. The Crew-12 team that arrived in February includes Nasa astronauts Jessica Meir and Jack Hathaway, European Space Agency astronaut Sophie Adenot, and Roscosmos cosmonaut Andrey Fedyaev. The other group arrived in November and consists of US astronaut Christopher Williams and cosmonauts Sergey Kud-Sverchkov and Sergei Mikayev.

Safe-haven instructions are uncommon on the ISS, although they have been used in recent years because of potential collisions with space debris and smaller changes in air leak rates. Astronauts have never been forced to leave the station in its 27-year history.