A recent episode of "The Signal", a podcast focused on the Joss Whedon show Firefly and film _Serenity_, had a segment discussing music in the fictional setting, and the theremin was discussed in that segment.
http://signal.serenityfirefly.com/shownotes.php?e=2170
http://signal.serenityfirefly.com/shownotes.php?e=2170