Rescue mission for NASA's stranded astronauts faces another major hit as race continues to save them

NASA has had a tough decision to make after their rescue mission to save their two stranded astronauts begins.

Starliner test pilots Barry 'Butch' Wilmore, 61, and Sunita 'Suni' Williams, 58, embarked on what was supposed to be short trip to the International Space Station (ISS) on 5 June.

But when thruster and leak problems hit Boeing’s Starliner capsule after lift-off, it meant that they couldn't return in the scheduled eight days.

The duo need an alternative mode of transport to get them home with the Starliner deemed unsafe to return to Earth.

Last month, NASA’s Commercial Crew Program manager, Steve Stich, said that their best bet would be to hop on SpaceX Crew-9’s return flight in February 2025.

“We have been working with SpaceX to ensure they are ready to respond with Crew-9 as a contingency,” Stich said.

“We have not formally committed to this path, but we wanted to ensure we had all that flexibility in place.

Barry 'Butch' Wilmore and Sunita Williams are currently stuck in space (NASA/Getty Images)

"Our prime option is to return Butch and Suni on Starliner. However, we have done the requisite planning to make sure we have other options open.

"I think Butch and Suni are ready to do whatever we need them to do."

Now, NASA have revealed that they've been forced to cut two astronauts from their next crew who will fly on a SpaceX rocket to the ISS to go and rescue the pair.

Astronauts Nick Hague and Russian Aleksandr Gorbunov will launch in September to return with Suni Williams and Butch Wilmore in February.

Zena Cardman and Stephanie Wilson have been cut from the crew as NASA said they've had to take into account spaceflight experience and other factors in their decision.

The rescue mission is set to begin (AFP via Getty Images)

Meanwhile, ex-NASA astronaut Scott Kelly - who'd spent almost a year on the ISS from 2015 to 2016 - reckons that the pair are doing just fine up there.

Kelly's career spanned from 1996 to 2016 when he retired, and he knows exactly what it's like to spend so long in space.

“I knew them before they were astronauts and we were all test pilots in the Navy," he told PEOPLE. "They'll be able to handle it."

Speaking about Williams, he added: “She is a great spirit of a person and I’m sure she’s not minding being up there for more time.

“She’s very enthusiastic about most things.”

On how to keep busy, Kelly explained: “You have some personal stuff, you sleep there, you have some computers and things.”