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

Suni Williams and Butch Wilmore originally planned to stay just a week on the space station, but problems with their Boeing vehicle forced them to remain there.

The Starliner crew was originally meant to stay on board the ISS for a week, but issues with Boeing's Starliner spacecraft severely delayed their return to Earth.