From Forbidden Planet, the first film to feature an entirely electronic score, to Wendy Carlos' switched-on Baroque synth in A Clockwork Orange, electronic music has always been strongly associated with science fiction.
Watching sci-fi, audiences expect to hear "futuristic" music, for which electronic bleeps and synthesized tones are a kind of shorthand. Unlike analogue instruments, which perpetually journey towards entropy, electronic tones suggest something empirical. And in our minds, the future is nothing if not precise, a time when things have been figured out - when margins of error have been nudged into obscurity.
Scoring science fiction with electronics also sidesteps the tricky proposition of considering authentically futuristic music: How to create a score which reasonably evokes a time beyond our own? Every component of music is subjective, and perpetually in flux. Language changes quickly from moment to moment, from generation to generation, from place to place. Scales are regional, generational. Even beauty is too closely wired to the resonances and tones that soothe our brains and summon stored, subjective, emotional memories to awareness.