If you’re a space fan and you’ve decided to hold off seeing The Martian on opening weekend until you know what to expect, I totally understand — I very rarely see films on opening weekends myself (I have a thing about overcrowded theaters, but that’s another story.) And I also hate to be sorely disappointed in films, which is all too often the case when I’m going in with particularly high expectations. This of course was exactly what I had with The Martian, having read and enjoyed Andy Weir’s book shortly after it was published and subsequently being thrilled not even a year later to hear that one of my favorite directors (Sir Ridley Scott) would be making the movie version of the novel. But, being the big ol’ space geek that I am I felt I would have been amiss to not see the film ASAP, and so I went this past Saturday afternoon. Here’s what I thought of it.

(Spoiler: just writing this gives me a big smile, so you already kinda know how I feel!)

The Martian, first and foremost, is a film that follows the source material (that is, Andy Weir’s book) very closely. If you enjoyed the book, chances are you will enjoy the movie. But even if you haven’t read the book you won’t be left in the dark: the story here is (in a nutshell) an astronaut/scientist gets stranded on Mars accidentally during a NASA exploration mission a couple of decades from now and then has to figure out how to survive long enough with the resources at hand to get rescued. In the meantime NASA has to figure out how to help him from 50 million miles away, using the resources it has on hand: namely, lots of brilliant people who can do complex math at a moment’s notice and know Mars like the backs of their hands.

That’s it. That’s the story. There are no alien monsters, no philosophical musings, no heavy-leaning on the boundaries of theoretical physics, no pretend deus ex machina technology to save the day. Aside from the expected advances the next twenty years may bring us, The Martian uses spaceflight technology as it stands today. Mission specialist Mark Watney is not going to get beamed back from Mars or delivered home via some ancient alien artifact; they have to go get him — using a souped-up ion-propelled space station that doesn’t yet exist, sure, but still it could — or die trying. (Of all or any of the wonderful ways that space can kill you.)

Meanwhile on Earth NASA has to try to avoid a global PR nightmare and losing support/funding for the entire Ares program, of which Watney’s Ares III mission is just in the middle.

Does The Martian succeed? You bet it does. But unless your title is “The Shawshank Redemption” you’re not a perfect movie, and there are ups and downs to The Martian too. Here’s my run-down:

Martian Wins:

• The hero of the movie (besides Matt Damon) is science. Problem-solving, specifically, and that’s what ultimately keeps Watney alive. This is something that we need to see more of in big-budget films, if you ask me… it’s not about who’s toughest or luckiest or shoots guns or has the best kung-fu moves, it’s the most resourceful and cool-headed that come out on top here.

• Teamwork, too. That’s also a big character in The Martian. Watney may be alone on an entire planet, but our whole world is behind him.

• The vistas of Mars are beautiful. We only see the areas that Watney lives and drives around in, of course, but they highlight the rugged beauty of Mars like I’ve never seen on screen. (You can see actual images of the same areas from NASA’s MRO satellite here.) Kudos for including craters in the otherwise southwestern-style landscape, dust devils, and a crescent Phobos in the sky several times.

• NASA isn’t the bad guy. In many space films NASA is portrayed as a cold, unfeeling entity that just wants to cover stuff up or make things difficult. In The Martian we see the many divisions of NASA that have to work together to solve a dire problem, from administration to engineers to the folks who maintain the archives. Being an astronaut isn’t easy, but neither is being NASA. (Maybe Weir/Scott’s next movie can be about NASA fighting House appropriations committees for mission budgets.)

Read more: Nine Real NASA Technologies in The Martian

• The Martian moves through (with the magic of montage, no less) a lot of the book’s sciencey sections very quickly, and leaves others out altogether. While this might seem irreverent to hardcore fans of the novel, it really helps it remain entertaining for a wider audience while keeping the run-time well below six hours (or requiring a Peter-Jacksonesque split into three films.) The book had a lot of science and engineering segments… I admit, I even glazed over in a few of them. While I missed some of the better rover-driving sequences in the film, I was OK with the abridgment. Everyone got the idea.

Martian Fails:

Most of these really are hard-fact-related, so if that doesn’t bother you then feel free to ignore the first three:

• This has been discussed several times online (and even Weir himself has said that he’d write it differently today if he could) but there are some not-quite-right science details about Mars in the film. Most notably is the portrayal of Martian storms… with just 1% of the atmospheric density that you find on Earth, a dust storm on Mars might look scary and make a big mess but you wouldn’t get blown around in it (nor would it likely throw a chunk of metal through your space suit or tip over your rocket.) Lightning could be a problem though, generated by charges but up between the fine grains of Martian sand (like ash clouds from a volcanic eruption) and you could potentially catch a fatal shock or lose sensitive electronics. Oddly enough Mars’ thin atmosphere is brought up near the end of the film, but seemingly ignored at other times.

(To find out how The Martian author Andy Weir calculated his Mars facts watch an interview by Mythbusters’ Adam Savage below:)

• Sound on Mars? While not zero like you would have in space, sounds on Mars would fade after only a few meters from the source… small noises like the whirring of robot servos or the clunk of a dropped solar panel would be imperceptible by human ears after a short distance. I don’t know how far away everything in The Martian was supposed to be from the camera, but I think they broke this law several times during Watney’s EVAs.

• I’m in doubt about the apparent lack of internal pressure in the astronauts’ EVA suits (they looked fairly flaccid) and the rapid compression/decompression of the airlocks, but that could just be my own ignorance there. (And speaking of pressure, I doubt they’d design a rover with rubber tires for use on Mars. Just sayin’.)

• As far as acting goes I thought everyone did a very good job playing their roles. Damon was approachable and fun even in the face of danger (like he is), Chastain and the Ares III crew were sufficiently archetypical to their mission roles, Jeff Daniels put his best “Newsroom” on for NASA’s administrator. The only oddness I personally picked up on was a lack of any sense of long-term duration of the Hermes crew as they traveled to Earth and back to Mars, a journey of almost two years. Every time you see them they felt as if they’d just left home, or at least just left the previous scene. Sure, the Hermes is a nice ship with a handy gravity-simulation torus section à la 2001 (why haven’t we built one of those yet?!) and a wonderfully spacious cafeteria and gym, but I’m thinking months of deep space travel in an emergency scenario has to weigh on you. Maybe they were just showing their “right stuff.” I don’t know. But it seemed a little strange.

Bottom Line:

Go see The Martian. It’s a wonderful and refreshing film that will make you feel good about the U.S. space program and what it may hopefully accomplish in the near future. A success at the box office ($55 million in opening weekend!) may not always be indicative of a good movie but in this case it is — good because people are excited about what humans can achieve, not what they can destroy, shoot holes in, or beat up. It’s no wonder NASA decided to really jump on the bandwagon and help launch this film. (Pun intended.) Science fiction only on its surface, The Martian is at its core a romance: and the love is all for science.

Get tickets to see The Martian at a theater near you.