SpaceX will launch a crewed NASA mission on Friday to return two astronauts from the International Space Station, after technical issues with Boeing’s spacecraft extended their stay for nine months, leading SpaceX CEO Elon Musk and President Donald Trump to suggest they were stranded for “political reasons.

The flight was scrubbed on Wednesday night, and the astronauts will return to the launchpad for their trip to the International Space Station.

NASA and SpaceX on Friday will count down to a long-awaited crewed rocket launch that will allow them to bring home U.S. astronauts Butch Wilmore and Suni Williams, who have been stuck on the International Space Station for nine months.