SPACEX and NASA will make a second attempt to launch two astronauts on a mission to the International Space Station in under one hours time.
The mission, dubbed Demo-2, is set to liftoff from the Kennedy Space Centre in Cape Canaveral, Florida, at 8:23pm BST (3:23 pm ET).
If the attempt proves successful, it would be the first crewed spaceflight to take off from US soil in nearly a decade.
It will also be the first time ever a privately developed spacecraft has launched humans into space.
The original launch window was May 27 at 9:33pm BST (4:33pm ET) but the launch was cancelled due to the weather.
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