With the MMM release of ROCKETSHIP X-M just a couple of weeks ago, how could you forget this score? RX-M was the first science-fiction film to feature the Theremin in its score by Ferde Grofe.
Ferde Grofe's score to ROCKETSHIP X-M is a real favorite of mine. By the way,the movie in 1950 was the first feature to usher in all those outer space sagas of the 1950's with the exception being a few movie serials like the great Flash Gordon series of the '30's.
Another thereminist to track down online is Carolina Eyck - her playing is very skilful and there are a couple of tracks on her YouTube channel that I find myself going back to every few months.