Astronauts Butch Wilmore and Sunny Williams are preparing to return to Earth after nine months on the International Space Station (ISS), awaiting the arrival of their replacements next week. Their departure is scheduled for the end of March.

The two astronauts will board a SpaceX capsule along with two of their colleagues who travelled to the ISS in September. Speaking from the space station on Tuesday, Williams said the most difficult test of the unexpectedly prolonged mission was waiting for their families on Earth.

“It was an emotional journey for them, probably more so than for us,” she said.

The failed Starliner mission

Wilmore and Williams had originally planned to stay in space just one week when they launched in June in Boeing’s new Starliner capsule as part of its first manned test after years of delays. However, the capsule experienced so many problems upon arrival at the ISS that NASA deemed it unsafe for manned flight and returned it to Earth empty.

The return of the two astronauts was further delayed due to the extra time needed to complete SpaceX’s new capsule that would carry the mission that would replace them, according to the Guardian.

Return with forced changes to the program

Finally, last month, NASA decided to use an already-tested capsule for the next mission, accelerating the launch to March 12. The two crews will remain together on the ISS for about a week before Wilmore and Williams depart with NASA’s Nick Haig and the Russian Space Agency’s Alexander Gorbunov.

Despite their long stay in space, the two astronauts have repeatedly stressed that they remain healthy and committed to the mission for however long it takes.