obviously i've seen 'forbidden planet' too much as it just doesn't seem right being in space without some inccessant bleeping. The following are albums rather than songs.
'selected ambient works' by aphex twin, (theres a few collections). basically just a bunch of spooky, weird noises. works pretty well in deep space!
''closed circuit' by 'electronic eye'. as the name suggests some authentic 90's techno from unsung hero Richard H. Kirk. pretty ambient.
'an empty biss beyond this world' by 'the caretaker'. about my favourite gaming music, also works well with 'stalker'! you'll either love it or it will drive you insane. It mostly sounds like an old big band record from the 50's that's scratched and jumping, being played at the other end of a very long tunnel.
'pocket calculator' by Kraftwerk, from 'Computer World', sing along whilst calculating delta v, etc
...to name just a few
btw someone recommended Tinariwen at the beginning of this forum. Hadn't heard them so i clicked the link. They are awesome, thanks for that, still grooving to desert guitars 25 forum pages later!