Stowaway is shrewd in its decision-making and even better in its execution.

The film is strongest when simply exploring the terrible notion of triage among the healthy, with everyone involved fully aware of which individual will be deemed the most expendable.

Empathy and compassion aren’t vulnerabilities in this narrative. They’re resources, with which you can defy the cold cosmos — though not without cost.

If you can buy the film’s unlikely core premise, you’ll be rewarded with persuasive speculative fiction in all its other aspects. Penna and company make it easy for audiences to do that, while putting four people whom they’ll come to really care about through all kinds of hell.

For the most part, aside from a slightly slack start, and its stirring but simplistic ending, that kind of well-researched procedural detail is what makes Penna’s film such an engrossing and surprisingly touching addition to a genre already bursting with splashier, more extravagant and more overtly sentimental titles.