They went to space for eight days – and could be stuck until 2025

One potential option being considered, they said, is to attach the two astronauts to a mission that is scheduled to launch in September, and return them to earth with that mission in February 2025.

That flight to the space station will be made by a SpaceX Crew Dragon craft. The initial plan was for four crew members to be aboard, but two of the seats could be left empty if needed.

That plan would mean the astronauts would spend more than eight months – rather than eight days – aboard the International Space Station.

If the Crew Dragon is used, the Starliner craft would be returned to earth without any crew, under computer control.

Nasa officials said it could take a week or more for a final decision to be made.

Ken Bowersox, NASA’s director of space operations, told reporters the chances of an uncrewed return of the Starliner “have increased a little bit based on where things have gone over the last week or two.”

“That’s why we’re looking more closely at that option to make sure that we can handle it,” he said.

Using a SpaceX craft to return the astronauts would be a blow to Boeing, which has for years tried to compete with the company and its more experienced Crew Dragon.

Earlier this week, Nasa used a SpaceX rocket to deliver more food and supplies to the ISS, including extra clothes for the two astronauts.

Last month, in a short press briefing, the pair said they were “absolutely confident” in the return trip and Starliner was “truly impressive.”