NASA reverses evacuation alert order for ISS astronauts

Five astronauts on board the International Space Station (ISS) were ordered by NASA to shelter in their spacecraft and prepare for potential evacuation as a ⁠Russian crew attempted to fix a worsening air leak on its portion of the orbital laboratory, NASA said.

The four astronauts of NASA's Crew-12 mission on board the station - two Americans, a French astronaut and a Russian cosmonaut - along with another US astronaut were ordered by NASA mission control at this afternoon to enter their SpaceX-built Crew Dragon spacecraft docked to the station, NASA spokesperson Bethany Stevens said.

They were instructed to don their spacesuits in case the air leak worsens and an emergency evacuation becomes necessary, Ms Stevens said.

NASA reversed the order ‌roughly two hours later and told ⁠the astronauts they could return to the station as the agency and its Russian counterparts examined the rate of leaking air.

Head of Space at Britain's Science Museum Libby Jackson said the move was taken "out of an abundance of caution" and reflected standard safety procedures aboard the station.

"It looks like Russia then have looked at the work site and decided not to proceed for now. So the crew have all gone back to their day-to-day operations, which is fantastic news," Ms Jackson said.

The leak in the Russian Zvezda module has existed for some time but has recently worsened, she said.

"It’s been there for some time, but it has got worse recently. Not to a point yet where the space station is compromised," Ms Jackson said, comparing the situation to "a very slowly deflating balloon" that can be kept stable by replenishing air supplies.

She also noted that the ageing station is approaching the end of its operational life.

"So parts of it are nearly 30 years old and it is getting towards the end of its life," she said, adding that NASA is already investing in a new generation of commercial space stations expected to begin operating before the end of the decade.

"There will be a transition. And one day, the International Space Station will be deorbited and be no more," Ms Jackson added.

NASA and Russia's space agency Roscosmos, the station's two primary operators, have debated for months over the cause and potential fixes of small air leaks aboard Russia's Zvezda service module, a key structure of the ISS, a football field-size orbital laboratory where ‌astronauts live and work in space.

Roscosmos did not immediately respond to request for comment.

The air leaks have been relatively minor in recent months but escalated today from a pound of air per day to two pounds, according to a senior NASA ‌official who asked not to be named.

The ISS is currently home to seven ⁠astronauts from two ‌missions, including the Crew-12 team - NASA astronauts Jessica Meir and Jack Hathaway, European Space Agency astronaut Sophie Adenot, and Roscosmos cosmonaut Andrey Fedyaev - who arrived in February.

The other crew of one US astronaut, Christopher Williams, and two cosmonauts, Sergey Kud-Sverchkov and Sergei Mikayev, ⁠arrived in November.

Kud-Sverchkov and Mikayev, who did not execute evacuation procedures, are using a saw to break into an area ⁠where they believe they can access the crack leaking air, the NASA official said.

NASA officials disagreed with this method, the NASA official said, prompting mission control in Houston to order safe-haven procedures.

Safe-haven orders are rare on the ISS, though pieces of space debris that risk colliding with the ISS and smaller changes in air leak rates have triggered the process in recent years.

Astronauts have never had to ‌evacuate the ISS in its 27 year history.