Astronauts home in on International Space Station air leak

Kenny Todd, deputy manager of the space station, said the leak was first detected more than a year ago but had increased in the past couple of months. A fresh round of testing overnight Monday revealed the leak was in a service module in the Russian segment, Todd said during a NASA briefing Tuesday.

"We're going to try and put a finer point on our troubleshooting plan," said Todd, explaining that the team is dealing with the same leak as before rather than a fresh one.

Russian space agency Roscosmos confirmed that the leak was coming from one of its service modules.

"Currently the search is underway to precisely locate the leak," the agency tweeted. "The situation poses no danger to the crew's life and health and doesn't hinder the station continued crewed operation."

NASA astronaut Chris Cassidy and Roscomos cosmonauts Anatoly Ivanishin and Ivan Vagner carried out the onboard tests.

"The size of the leak identified overnight has since been attributed to a temporary temperature change aboard the station with the overall rate of leak remaining unchanged," NASA said in a blog post Tuesday.

While crew members experience comfortable pressure while living in the orbiting laboratory, the space station does experience tiny air leaks over time.

Regular repressurization is possible thanks to nitrogen tanks that are included on cargo resupply missions that deliver them to the space station.

The next resupply mission is due to arrive this weekend. The uncrewed Northrop Grumman Cygnus cargo craft will launch from the Wallops Flight Facility in the US state of Virginia on Thursday night.

Then the crew members will rotate. NASA astronaut Kate Rubins and Russian cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov will launch from the Baikonur Cosmodrome in Kazakhstan on October 14 and dock at the space station, while Cassidy, Vagner and Ivanishin will depart the space station on October 21 and return to Earth.

The trio will have spent 195 days together on the space station after launching in April.

Then, on October 23, the SpaceX Crew-1 mission will launch to the space station, carrying NASA astronauts Mike Hopkins, Victor Glover, Shannon Walker and Japanese space agency astronaut Soichi Noguchi.