Nasa looking for air leak on board the ISS

Astronauts on board the International Space Station are trying to find a mystery air leak.

Despite the leak sounding pretty serious, Nasa says it's fairly common and although it needs to be fixed, the leak "presents no immediate danger to the crew or the space station".

The leak was first spotted in September 2019, but it did not interfere with normal operations and the rate of air loss was not increasing or high enough to cause a problem. So Nasa simply monitored the situation and told the astronauts to focus on other space station work.

After all, it's been a busy few months for the space station that have included astronauts taking space walks to make repairs on the outside of the ISS and SpaceX completing the first crewed commercial mission to the orbiting lab.

Speaking to Space.com Dan Huot from Nasa said: "Now that we have a relatively quiet period in the operations, the crew will be shutting the hatches to every single module so the ground can monitor each module's pressure to further isolate the source."

Locking off hatches inside the station means astronaut Chris Cassidy and Russian cosmonauts Ivan Vagner and Anatoly Ivanishin have had to move to the Russian built Zvezda service module.

The Zvezda module was one of the first pieces sent up into space during the construction of the ISS and provides the space station's life support system. It's about the length of three double-decker buses, but its living quarters are normally home to two astronauts, not three.

Only Nasa astronaut Chris Cassidy had personal items outside of the Russian segment, as his sleeping quarters are normally in a different module of the space station.

Nasa says that while this leak is at a higher rate than normal, it is still within specifications. Air leaks out of the station all the time, with routine cargo missions sending nitrogen and oxygen tanks to ensure the modules of the ISS stay at the right pressure.

Astronauts had to fix a similar leak back in 2018 when a small hole was found.

To prepare for any potential problems like air leaks, astronauts deal with simulations during six months of training before their stays onboard the space station.