Bad weather has prevented the first launch of Nasa astronauts from US soil in nine years.
NASA and SpaceX have been forced to cancel Wednesday's historic launch and are now due to attempt lift-off on Saturday at 8.22pm UK time.
Billionaire Elon Musk's private rocket company was set to launch two astronauts into space tonight - the first step, he claims, on the path to landing on Mars.
Two NASA astronauts, Doug Hurley and Bob Behnken, were to take off from Florida - the first spaceflight to take off from the US in nine years.
But poor weather conditions have forced NASA to reschedule the flight until Saturday.
The rocket was due to set off from its launchpad at the Kennedy Space Centre in Florida at 4.33pm - 9.33pm over here - with Nasa astronauts Robert Behnken, 48, and 53-year-old Doug Hurley on board.
Just 15 minutes or so later - at around 9.50pm - and having jettisoned the first-stage part of the rocket, the section carrying the Crew Dragon was set to fly over the UK.
According to MeteorWatch, the spacecraft would have passed overhead from a westerly to easterly direction and its flight could have been visible for around three or four minutes in the lower southern part of the sky.
The Demo-2 mission is intended to show that Musk's SpaceX company can transport people safely to space as it approaches the final stages of its bid to achieve Nasa certification for its plans for commercial space missions.
While the lift-off should run to timetable, those wanting to be sure they do not miss out can follow @VirtualAstro on social media for any changes to live timings.
