Nasa and SpaceX are trying once again to launch two astronauts into space in a historic mission.
The launch will be the first time that astronauts have been launched from US soil since the Space Shuttle programme ended in 2011.
And it will be the first time that any private company have taken humans into space.
But it could be delayed, once again, because of the weather. Wednesday’s attempt had to be postponed just minutes before launch for fear that it could “trigger lightning”.
Official forecasts suggest that conditions could once again cause problems for the launch.