What is the greatest science fiction-inspired song ever written?S

Science fiction themes have ruled pop music, from 1950s rockabilly tunes about Martians, to David Bowie's 1970s Ziggy Stardust and Janelle Monae's current tales of the android Cindi Mayweather. But what is the absolute best song with science fiction themes that's ever been written?

Tell us your choice, and be sure to include a picture or video!