It's the first time in history a commercially built rocket is going to launch humans into space.
Astronomy Ireland says we'll be able to catch a glimpse of Elon Musk's SpaceX craft over Ireland tonight.
The company will become the first private firm to send NASA astronauts into space when they launch from Florida later today.
Chairman of Astronomy Ireland, David Moore, says the spacecraft will be visible just below the moon at around 9.53pm.
''It is the first time a commercially built rocket is going to launch humans into space'', he said.
''And they have huge plans to put millions of people on Mars, by the end of this century''.
