Astronauts Suni Williams and Butch Wilmore failed last year with the thrusters on Boeing Starliner capsules and they were unable to fly to the dock.

And if they can't dock, they don't know if they can go home again.

"Doing is a priority," Wilmore told BBC News. "If we can't dock, can we return it? We don't know."

Astronauts have been traveling on test flights that last eight days. Instead, they ended up staying in space for nearly 10 months.

The first challenge was to dock safely and successfully at the ISS, which they managed to do within minutes of mission control on the ground, helping them restart the craft thruster.

Mr. Wilmore said they may never see the earth again, "it must be in our minds."

But both astronauts said that at that moment, they did not speak loudly about the worst because they were trained to solve the problem.

Ms Williams told the BBC: "You kind of read each other's thoughts and know where we're going."

"Those are not expected," she admitted. But the mind quickly turned to the solution: "At the same time, you know, what are we going to do? What should we do?"

The couple's legend began in June 2024. They participated in the first crew test flight of Starliner Spacecraft developed by Aerospace Company Boeing.

However, after many technical issues were carried out during the flight, the choice of Starliner, who took astronauts home as planned, was considered unworthy of the risk - given that the couple could be brought back by another company SpaceX.

So they stayed in space until they hitchhiked back to the SpaceX capsule. For its part, Boeing insists that its own capsules are safe to use – proved to be correct when the spacecraft returns in September 2024.

After several months of experimentation, Ms. Williams and Mr. Wilmore finally returned to Earth on March 18.

At this stage of their mission, the couple repeatedly described as stranding, meaning they had no means to be able to leave the ISS.

But that's not the case, because the space station always has spacecraft attached to emergency situations, which can take astronauts back to Earth as lifeboats.

Still, the two had a longer stay than expected - although NASA accepted the introduction.

"We know no one will let us down ... we know everyone has our support and are looking for us," Ms. Williams said.

In a stumbling process, the two even found themselves in the middle of politics, as U.S. President Donald Trump accused his predecessor, Joe Biden, of putting them in space.

But astronauts say they overlooked politics and were not abandoned. "We can't say it at all," Mr. Wilmore said. "We understand that space flight is difficult, and human space flight is even more difficult."

Two months later, both astronauts said they felt healthy because their workouts in a zero-gravity environment paid off.

Mr. Wilmore explained that moving in zero gravity means your body doesn’t need much time to recover from daily squats and deadlifts.

He said he did squats and deadlifts “every day of nearly 10 months”, which meant that he was back to Earth “literally, I’ll be strong all my life.”

Ms. Williams agreed - she landed on Earth for a full marathon once tied to a treadmill - but said it wasn't always easy to readjust the world's weight.

"Just put gravity back on your head, on your back, all of this stuff is a bit painful," she said.

Since their return, the couple has been working with NASA and Boeing to address the problem of the spacecraft that brought them into space last summer.

"We really hope to have a chance to drive a Boeing superstar in the future," Wilmore said.

Both astronauts said they will fly in person once these technical issues are resolved.

"This is a very capable spacecraft," Ms. Williams said. "It has unique features compared to other spacecraft, and these spacecraft are really well suited for future astronauts."