SpaceX delivered a four-person crew to the International Space Station early Sunday, setting the stage for Barry Wilmore and Sunita Williams to depart.

Because of faults with Boeing’s Starliner, Suni Williams and Butch Wilmore had to wait months for a ride back to Earth on a different spacecraft.

NASA removed two astronauts from its Crew-9 mission to allow for Williams and Wilmore to join the cohort, and return onboard the SpaceX Dragon − which carries four people at a time. The altered Crew-9 − only Hague and Gorbunov − launched aboard the SpaceX Dragon Freedom in late September.