The SpaceX launch has been abandoned just minutes before lift-off due to poor weather.
Foul weather has postponed the first launch of NASA astronauts from US soil in nine years.
SpaceX, the private rocket company of billionaire entrepreneur Elon Musk, was forced to scrub a planned launch of two Americans into orbit from Florida.
The mission would have marked the first spaceflight of NASA astronauts from US soil in nine years.
The countdown was halted less than 17 minutes before the SpaceX Falcon 9 rocket was due to lift off from the Kennedy Space Center this morning before the scheduled 6.33am (AEST) launch.
Astronauts Doug Hurley and Bob Behnken had been preparing for a 19-hour ride aboard the company's newly designed Crew Dragon capsule bound for the International Space Station.
The next launch window is set for Saturday afternoon.
After taking a brief moment to keep an eye on the weather, the hatch was closed on the SpaceX Crew Dragon capsule holding astronauts Bob Behnken and Doug Hurley.
They stayed locked inside the capsule, waiting for lift-off, while launch officials continued to monitor for storms and technical issues before the launch was called off.https://twitter.com/SpaceX/status/1265739654810091520?ref_src=twsrc%5Etfw
The US hasn't launched its own astronauts into space since the Space Shuttle Program ended in 2011. Since then, NASA's astronauts have had to travel to Russia and train on the country's Soyuz spacecraft.
Those seats have cost NASA as much as US$86 million (A$130 million) each. But the space agency chose not to create its own replacement for the shuttle.
The mission would have been the first time that a private aerospace company has carried humans into Earth's orbit.
- With CNN, AAP
Source: 9News https://www.9news.com.au/world/spacex-launch-rocket-florida-elon-musk-falcon-9-nasa/9504ddaf-41bc-4eea-a13f-45edb86b1ab5