Four astronauts will soon launch to the space station — a flight that will kick off a series of events culminating in the long-awaited return of NASA astronauts Suni Williams and Butch Wilmore.

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.

In a news briefing following the landing, Nasa spokesperson Steve Stich said: "From a human perspective, all of us feel happy about the successful landing, but then there's a piece of us - all of us - that wish it would have been the way we had planned it.