SpaceX launched 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.”

Reaching orbit from NASA’s Kennedy Space Center, the newest crew includes NASA’s Anne McClain and Nichole Ayers, both military pilots; and Japan’s Takuya Onishi and Russia’s Kirill Peskov, both former airline pilots. They will spend the next six months at the space station, considered the normal stint, after springing Wilmore and Williams free.

The U.S. space agency and SpaceX are on a mission to bring home astronauts Butch Wilmore and Suni Williams. They have been stuck on the International Space Station for nine months.