250,000 miles from home, the hardest thing to face...is yourself
Why it is hard sci-fi
Sam Bell is a single human operator at a helium-3 mining station on the lunar far side, three years into a contract. The film is built on real engineering. Lunar regolith mining, helium-3 as a fusion feedstock, return capsules, and a station that runs almost unattended. The hardness comes from the operational realism. A small crew, a long contract, and a maintenance schedule that runs the show.
Science inside it
Helium-3 mining as a fusion fuel concept, far-side communication relays, long-duration isolation effects on cognition, and the engineering of an automated station with a single human in the loop. The film also uses the Earths line of sight from the lunar far side as a plot constraint, which is a real consequence of the geometry.
Spoiler alert
There is no rotation home. Sam is a clone, one of a sequence of identical workers grown in a hidden bay and woken into a fake three-year tour. When this Sam meets the next clone after a rover crash, the two of them work out the structure of the deception by reading their own DNA records and the stations medical logs. The film commits to the procedural rather than the philosophical, and the hardness lives in that choice.