The Crew-10 mission will send four astronauts to the space station to take over for Butch Wilmore and Suni Williams’ crew, finally allowing their return home.

NASA and SpaceX on Wednesday night scrubbed the Falcon 9 launch of a flight intended to retrieve from the International Space Station astronauts Suni Williams and Butch Wilmore, who have spent nine months in orbit.

The quartet will head to the International Space Station for a roughly six-month stay. They'll relieve four other astronauts — NASA's Nick Hague, Suni Williams and Butch Wilmore and cosmonaut Aleksandr Gorbunov, who will come back to Earth a few days after Crew-10 docks.