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

A Crew Dragon spacecraft with four people on board docked with the International Space Station March 16, setting up the departure of an existing station crew in the coming days.

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