Silent Running (1972)

Douglas Trumbull spent the 1960s building the effects that made 2001: A Space Odyssey and Close Encounters look the way they do; Silent Running was his chance to direct a film of his own, and he used it to make something quietly radical — an intimate, mournful environmental parable dressed as a space adventure, with a budget a fraction of the films he'd built his reputation on. Where his mentors built vast, cold vistas of space, Trumbull turns his camera inward, toward a single man and three small robots trying to keep something alive.

Bruce Dern carries nearly the entire film essentially alone, playing Freeman Lowell's devotion to Earth's last forest as something between religious conviction and genuine derangement — a performance the film never fully resolves as heroic or unstable, which is exactly what makes it work. Huey, Dewey and Louie, the three drone robots Lowell reprograms and befriends after events force his hand, remain one of cinema's most successful non-verbal character creations: performed by double-amputee actors walking on their hands inside compact robot shells, giving the drones a genuinely alien, non-human physicality no CGI creation of the era could match.

The film's climax — Lowell alone in an escape pod, watching the last dome drift into the void with only a single drone left to tend it — is one of the most quietly devastating endings in 1970s science fiction, made stranger and sadder by Joan Baez's earnest folk songs on the soundtrack. It's an odd, personal, occasionally clumsy film, and one of the genre's earliest and most sincere ecological warnings.