The Boeing Starliner spacecraft successfully completed its uncrewed flight back to Earth, NASA announced overnight. The return ended the Starliner’s most recent flight test months later than intended and leaves its original crew, NASA astronauts Barry “Butch” Wilmore and Suni Williams, aboard the International Space Station until next year.

The two astronauts who crewed the Boeing Starliner have greeted their replacements, who docked Sunday morning at the International Space Station.

The four newcomers will spend the next few days learning the station’s ins and outs from Butch Wilmore and Suni Williams. Then it will be time for those two to end their nine-month stay and head home.