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.

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

After their flight was scrubbed on Wednesday, four astronauts successfully lifted off, which will allow two NASA astronauts to return to Earth after an unexpected extended stay in orbit.