Deteriorating weather conditions at the Kennedy Space Centre saw the first manned space mission from American soil in nine years abandoned just minutes before lift off.
Astronauts Doug Hurley and Bob Behnken were in the final 17 minutes of the countdown of the SpaceX Crew Dragon mission to the International Space Station when the launch was aborted.
Fears of thunderstorms in the skies above Florida forced controllers to stop the mission, which would have been the first by the US since the Space Shuttle programme was ended in 2011.
A second attempt will be made to launch what would also have been the first commercial space flight on Saturday
The SpaceX Dragon and Falcon rocket were developed by a private company owned by billionaire Elon Musk to provide a commercial “taxi service" to the ISS for the American space agency Nasa.
The timing of the launch window was crucial in order for the astronauts to dock with the space station as its orbit carried it overhead in Florida.
SpaceX is one of two US companies who have won Nasa contracts to fly astronauts to the ISS and hoped it had beaten the rival Boeing Starliner in the race to put America back in space.
It is the final step in certification needed to operate long-term manned missions to space.
Mr Behnken and Mr Hurley were chosen by Nasa to be astronauts in 2000.
They have each flown twice into orbit on space shuttle missions, but this is the first time they have worked together on a mission.
Mr Hurley, the spacecraft commander in charge of the launch, landing and recovery of the vehicle, was a fighter pilot in the US Marine Corps.
Mr Behnken, who will serve as the mission's joint operations commander and take responsibility for the rendezvous, was a flight test engineer with the US Air Force.
The pair were wearing spacesuits designed by SpaceX and a Hollywood costume designer.