Hi guys,
Thought you might like to know - NASA has set up a Soundcloud account and uploaded about 60 radio clips and equipment sounds, covering many aspects of its missions. There's two sets of shuttle files!
Don't know if they'd be usable in future updates?
https://soundcloud.com/nasa
BBC story I found out from:
http://www.bbc.co.uk/news/technology-29724071
Rob