Can sound exist in a vacuum?
No
Yes...my hoover is loud when I turn it on!
Ignore Eddie's remark. His Hoover is not in a vacuum. It only creates a partial volume inside itself.
Since sound is produced by the movement of molecules, and there are no molecules in outer space, you cannot hear sound in outer space.
The sound of rockets in space in scifi movies is merely "artistic license" — they are artificially added for effect.
I hope this helps a little more. Thanks for asking.