I saw some of these on tv the other day, and I thought it was kind of relevant to my current uni work as it's some really nice early examples of attempts at wacky abstract visuals done by the BBC, and with a very pronounced "outer space" flavour.
I genuinely don't know how they do this kind of thing, and I'd be really interested in finding out. I think it has something to do with visual feedback (you know, when you point a camera at a tv and the tv image goes on forever) but beyond that I'm stumped.
The one above is probably the most famous one. Notice how the music stays the same?
And finally, here's an example of how the intros started to get lame after more sophisticated '80s technology began to be introduced:
I just think the older ones just have a lot more charm. The music's still pretty cool, though.