You might think that if you were stranded on Mars, you would feel hopeless and depressed. Well, you wouldn’t if you were Mark Watney, the protagonist of Ridley Scott’s adaptation of Andy Weir’s bestseller “The Martian.”

And who else could pull off a smiling, cheery astronaut, even as he is dying on Mars, but Matt Damon? Watney rarely allows himself to let his situation get him down. He’s much too busy calculating mathematical equations to figure out how he’s going to survive until NASA figures out that he’s alive and sends someone to rescue him.

If this sounds vaguely familiar, it’s because Damon recently played another astronaut stranded on a planet, in last year’s epic space adventure “Interstellar.” (Jessica Chastain was also in both movies.)

I keep hearing this movie described as “a love letter to NASA,” and it absolutely celebrates the camaraderie, teamwork, and sense of adventure for which the space agency is known. But more than that, it is a testimony to the ingenuity and determination of one man who refuses to give up.

Throughout the movie, I couldn’t help thinking, “I would never have thought of that” and “Well, that would be the last straw for me.” I clearly don’t have the knowledge base or mental stability required to be a space explorer. I kept waiting for him to crack, but I guess they weed out all the sissies from the space program with psychological testing.

I also kept waiting for some flashback scenes of Watney with his loved ones back on Earth. They never mention a girlfriend, only his parents, and even though there are brief scenes with the other astronauts’ families, we never see Watney’s parents, even though he mentions them a couple times.

Perhaps this was to show us that Watney wants to live for the sake of living, because he has a zest for life, not because he wants to see his children grow up or because he’s made a promise to a girlfriend that he would come back, which is how this is usually done.

Or maybe, this just isn’t a movie about family. Not the blood-related kind, anyway. It’s more about the faith and trust and the love of science that bond all these people together – the stranded astronaut who says “I love what I do,” the Ares 3’s other five astronauts who have become his friends, and the entire ground crew at NASA, who are faced with making tough decisions without much time to consider the odds.

And most of all, it’s about optimism in the face of adversity – a quality we should all aspire to.