Outer Space videos

[UKHypnotist]

Nearly all NASA footage is public domain, that is why you see people streaming it on youtube.
However I think you will get hit for duplication, worth a try, add some different music.

Glad you qualified that with "nearly". Any footage with people (astronauts or lecturers) in it would not be considered Public Domain in the strict sense; as any worldwide broadcast (YouTube is considered worldwide broadcasting) of such footage would require publicity rights in the form of model release for each person whose image is shown. You could not "put different music" to such footage, either.