Three marooned astronauts. Only 55 minutes left to rescue them. While the whole world watches and waits...
Why it is hard sci-fi
A 1969 film about three Apollo-era astronauts stranded in low Earth orbit when their service module fails. Almost the entire film is a procedural rescue. NASA budgets a single launch window, weather grounds the rescue craft, oxygen budgets are tracked in minutes, and the crew accept that one of them must die for the other two to survive. The film was made before Apollo 13 and reads as a rehearsal for the real thing.
Science inside it
Service-module propulsion failures, oxygen budgeting, EVA transfer between vehicles, atmospheric reentry constraints, and the operational realities of managing a launch window from a single pad. The Soviet rescue subplot is fictional but the procedural beats are accurate to the period.