They're not lost in space, they're loose!
Why it is hard sci-fi
A 1974 student film by John Carpenter and Dan O Bannon. A long-haul crew in a small ship destroys unstable planets to clear hyperspace lanes for colonisation. The crew are bored, sleep-deprived, and getting on each others nerves, which is the most accurate portrayal of long-duration spaceflight psychology in any film of the era. The bomb that argues phenomenology with the captain is the films thesis.
Science inside it
Long-duration crew psychology, autonomous munitions with goal lock-in, Cartesian doubt as a way to halt a runaway weapon. The films later joke about a beachball alien is famous, but the argument with Bomb 20 about whether anything outside the bomb exists is real philosophy of mind played for laughs.