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.

NASA was due to launch a SpaceX rocket from Florida carrying a replacement crew for the International Space Station in a mission that would set up the return to Earth of US astronauts Butch Wilmore and Suni Williams - stuck in space for nine months after a trip on Boeing's faulty Starliner.