The answers we seek are just outside our reach.
Why it is hard sci-fi
A near-future astronaut is sent to Neptune to investigate his missing fathers research outpost, the source of a series of antimatter surges destabilising the inner solar system. The film is procedurally rigorous about transit. Earth-Moon transfer with a commercial flight to a militarised lunar base, a Mars stop-over for a deep-space launch, and a long-duration solo run to Neptune. The films interpersonal arc is uneven but the engineering progression is the right shape.
Science inside it
Antimatter as a power source with a realistic instability case, the operational shape of a cislunar economy with private spaceflight and lunar mining piracy, the medical screening regime for astronauts on long-duration missions, and the practical problem of an outbound solo with a body of communications all at light-delay.
Spoiler alert
McBrides father has been alone at the Lima Project for sixteen years and has refused to come back. The antimatter surges are a side effect of the projects ageing reactor failing in stages. The protagonist initiates the destruction of the station and uses its blast wave as a transfer impulse for the return trip. The film commits to that piece of engineering and gets the trajectory right.