I came of age at a time when outer space was a potent symbol in popular culture.
This quote from an interview with historian Nicholas de Monchaux sheds light on why:
[T]he space of outer space is… a space that humans cannot actually encounter without dying, and so must enter exclusively through a dependence on technological mediation.
If space is death, the space ship is also a casket – a vessel in which to cross the river Styx. In movies like 2001 and Alien, the protagonists mostly fight to live yet they are always already entombed, enveloped by the void of space.
What makes these movies thrilling is not a suspension of disbelief but the directness with which they can summon our innermost fear by projecting us into limbo; floating, weightless, ghosts in purgatory.