A space western and a blissed-out cosmic high, “The Martian” stars Matt Damon as an American astronaut who, like a latter-day Robinson Crusoe, learns to survive on his own island of despair. At once epic and intimate, it involves a dual journey into outer and inner space, a trip that takes you into that immensity called the universe and deep into the equally vast landscape of a single consciousness. For this accidental castaway, space is the place where he’s physically marooned, but also where his mind is set free — a dynamic that of course invokes moviegoing itself.

Perhaps that’s one reason Ridley Scott keeps returning to deep space. This is the third of his films — after “Alien” in 1979 and “Prometheus” in 2012 — set beyond the dark side of the moon. Hands down it’s also the funniest, loosest and most optimistic of the group, at once an ode to far-out adventuring and to terra-firma home, a sweeping, old-fashioned entertainment and a plaintive portrait of solitude as both a creative necessity and a danger. It also serves as a nice plug for NASA, which has returned the favor by pushing the movie on its website. (On Monday, scientists announced that signs of liquid water could be seen in photographs taken on Mars by a camera on the Mars Reconnaissance Orbiter, timing that suggests NASA certainly has the whole cross-promotion thing down.)

Based on the novel “The Martian” by Andy Weir that Drew Goddard has turned into a fast-moving, streamlined script, the movie focuses on Mark Watney (Mr. Damon), who, during a windstorm on Mars, is accidentally left behind by his team. Mr. Scott likes the action to hit hard and fast: One minute Watney is joking with his space buddies — Jessica Chastain leads a crew that includes Kate Mara and Michael Pe — and minutes later he’s been hooked like a fish by some flying metal that knocks him out. Believing him dead, the crew takes off, as does the movie, which soon becomes a tale of two planets with initially competing narratives, one involving Watney’s efforts simply to stay alive and the second centered on NASA’s postdisaster strategizing.

After some self-surgery to deal with the rod spearing his gut, along with some anxious stock-taking — he has plenty of tunes but not enough air, water and food to survive for long — Watney gets down to the business of living, including farming. “I’m not going to die here,” he helpfully mutters, helpfully because he talks out loud a lot whether just murmuring to himself or recording a video entry in his growing space log. The log keeps the words flowing in what could have been a fairly quiet movie, creating an animated lively babble that approaches the chummy feel of a video face chat. Watney makes for affably pleasant if worrisome company, and if there isn’t much mystery to him it’s because the purity of his struggle doesn’t leave him, at least, time for deep dives into questions of existence.