I don't know if anybody's heard of SomaFM. It's an online radio station. They've got a cool new channel called "Mission Control", and it's basically a nonstop mix of mission-control-to-astronauts radio chatter with just a little bit of ambient sounds mixed very low under the NASA communications. I've been listening to it for a couple hours now. It's strangely soothing. The com chatter sounds authentic to me, but real space buffs may know otherwise, and YMMV.
It's neat background music, anyway, and I thought I'd share.
http://somafm.com/
No affiliation with SomaFM btw, just thought it was cool.
