The crew-swap mission will enable NASA’s Butch Wilmore and Suni Williams to return to Earth from the International Space Station.

Suni Williams and Butch Wilmore were only supposed to be in space for about a week when they launched in June, but problems with their Boeing Starliner spacecraft extended their journey for months.

Suni Williams and Butch Wilmore are one more step closer to returning to Earth after an initially short mission became an extended, monthslong stay aboard the International Space Station.