Poor weather has forced SpaceX to call off the launch of Nasa astronauts Doug Hurley and Bob Behnken to the International Space Station (ISS), the BBC reports.
The two men were due to go up from the Kennedy Space Center in what would have been the first orbital mission from the US in nine years.
But unfavourable atmospheric conditions prompted controllers to call a stop just 16 minutes before lift-off.
The next opportunity for SpaceX and Nasa will come on Saturday.
If that’s no good, there would be a third opportunity on Sunday.
Not since the retirement of the shuttles in 2011 has America been able to launch its own astronauts into space – a big gap in which the US has had to rely on Russian Soyuz vehicles.