Russia delays launch of relief ship to keep investigating space station leak

Russia is delaying the launch of a ship to bring two Russian cosmonauts and an American astronaut back from the International Space Station (ISS).

Despite tense relations due to the Ukraine war, Russia and the United States still collaborate closely on the ISS. (AP)

Russia is delaying the launch of a ship to bring two Russian cosmonauts and an American astronaut back from the International Space Station (ISS) while it investigates a pressure loss in another module, its space agency said on Monday.

Roscosmos and the U.S. space agency NASA had said that a Soyuz MS-23 ship would be launched on Feb. 20 to bring back Sergey Prokopyev, Dmitry Petelin and Frank Rubio.

But in a video statement, Roscosmos head Yury Borisov said a decision had been taken to push back the launch until no later than March 10 while a team investigates the cause of a pressure loss in the cooling system of the Progress MS-21 cargo ship, which is due to undock from the ISS on Feb. 18.

Borisov also showed pictures that American colleagues had taken with a robot arm of the external damage believed to have caused a loss of pressure on Dec. 15 in the cooling system of another module docked to the ISS, Soyuz MS-22.

This craft was originally due to return the three men to Earth but, owing to the leak, will now be sent back unmanned.

The pictures showed a small hole surrounded by brown stains. Borisov said it could have been caused by a meteoroid or manmade space debris.

Roscosmos said the damaged modules were sealed off from the rest of the station and there continued to be no threat to the safety of the seven crew on board - three Americans, three Russians and one Japanese.

Despite tense relations due to the Ukraine war, Russia and the United States still collaborate closely on the ISS.

The Soyuz craft are used to ferry crew to and from the station, while the Progress vessels deliver equipment and supplies.