A SpaceX capsule delivered four astronauts to the International Space Station (ISS) early on Sunday in a Nasa crew-swap mission that will allow a pair of stuck astronauts, Butch Wilmore and Suni Williams, to return home after nine months on the orbiting lab. An otherwise routine crew rotation flight, the Crew-10 mission is a long-awaited first step to bring Wilmore and Williams back to Earth.