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.

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

A new batch of astronauts are headed to the ISS, who will take over from the current crew including two people who found themselves on an unexpected 9-month stay in space.