SpaceX's Falcon 9 rocket lifted off at 7:03 p.m. ET (2303 GMT) from NASA's Kennedy Space Center in Florida carrying four astronauts who will replace Wilmore and Williams, both of whom are veteran NASA astronauts and retired U.

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