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An astronaut is stranded on the red planet in The Martian.

An astronaut is stranded on the red planet in The Martian.

Courtesy of twentieth century fox

Here’s what Ridley Scott has to say about the science in The Martian

If you’re planning on watching The Martian, Ridley Scott’s newest sci-fi blockbuster, get ready to fall in love. No, we don’t mean with Mark Watney (Matt Damon), the movie’s intrepid astronaut hero who gets stranded on Mars after a NASA mission goes awry. The story’s real heartthrob is, well, science. Between the technologies showcased on the Mars mission and its breathtaking Hermes spacecraft, Watney’s ingenious solutions for staying alive on a deserted planet, and the creativity of scientists back on Earth, the story reads like a love letter to science—and a surprisingly plausible one at that. To get a deeper insight into how its creators balanced realism and movie magic, we spoke with director Ridley Scott; Andy Weir, whose debut novel provided the tale; and Jim Green, NASA’s director of planetary science and an adviser on the film. These interviews have been edited for clarity and consistency. 

Q: Was it important to each of you to get the science in The Martian right?

Andy Weir: I'm one of those guys that will nitpick the science in a story. It really takes me out of a story when there's some blatant error, and I didn't want that to happen to my readers … And if you actually pay attention to all the science and all the detail, it ends up providing you with plot points, and that's really cool.

Ridley Scott: For the most part, it's all as accurate as we can possibly get it … That was refreshing, I loved it. I like to be restricted by the actual science of it. How do I illustrate what it means when someone says, “We'll do a slingshot around the earth and we’ll never slow down, and by doing that we will conserve fuel?” Those kinds of questions I thought were really interesting.

Jim Green: With all that said, when I worked with Arthur Max, who was Ridley’s main set designer, I said to be inventive, be creative, and use your ability in art to do something that feels right.

Q: A lot of the story incorporates technology we haven’t built yet. How did you manage to keep the science realistic? Where did get all this information come from?

A.W.: I've been a space geek my whole life, but I didn't know anyone in aerospace at all at the time that I wrote the book. I do now! My primary source was Google … I read tons and tons of research. Also, originally The Martian was a serial that I had posted on my website chapter-by-chapter. If there were errors in the physics or chemistry problems or whatever, [my readers] would email me. It was great. I got sort of crowd-sourced fact checking.

R.S.: Almost immediately [after] I decided to do it, we started to have conversations with NASA about process, the habitats, the Mars Ascent Vehicle (MAV), the suits and everything. And they sent us pictures, almost like photographs, of what they hoped it would all be. If there had been anything in [the screenplay] that actually was suspect—they are not shy—they would have said so.

J.G.: We took [Ridley] to Johnson Space Center. We gave him the opportunity to see what the Habs [space habitats] are like … where do you make food, what do the vehicles look like, how do they function? All the things that cannot be said in the novel where all you have to do is paint that picture, and that picture is worth a thousand words, add to the realism of the story.

Q: Jim, Andy, how heavily were you both involved in making the movie?

J.G.: I quickly realized the difference between helping to write the script and adding to the visual [realism] and how things are created [that] complement the story. And that latter part was what I was involved in. The radioisotope thermogenerator [a radiation-powered electric generator] –- what does it really look like? How hot does it get? How much radiation does it produce? How would you handle it? On the Hermes mission, to make artificial gravity –- what would it look like, how fast would it need to spin, what would the displays look like? What is NASA’s concept of rovers on Mars currently, what is NASA’s concept of the habitats that you would place on Mars?

A.W.: Most of my job was to cash the check! But they chose to involve me, so when Drew Goddard was writing the screenplay, we talked on the phone a lot, almost every day. Then, while they were filming, I would get questions filtered down from Ridley. And the level of detail in those technical questions made me realize that they're really putting effort in the scientific accuracy. [Ridley] said like, "Hey, can we show Mark [Watney] out on the surface of Mars, with the EVA suit on, pouring hydrazine from one container to another?" I said, "No, I don't think so, because hydrazine is really volatile and in Mars's atmospheric pressure it would just boil off.” They're like, "Okay, then we won't do it."

Q: Is there anything in the story that is just not at all plausible—total movie magic?

J.G.: There are a number of things in it, and not a large number, that are close but are not exactly correct. The starting dust storm—dust storms on Mars are not as hazardous as portrayed in the movie. Because of Mars’s thin atmosphere it really doesn’t produce the effects of blowing anything over. There were a number of other things that were more minor. The breathing mixture within the suit would be primarily oxygen, not a mixture of oxygen and nitrogen, because nitrogen doesn’t help the bends. That’s an element that’s not well known, unless you contact somebody at Johnson Space Center who really knows suit architecture … [It’s] perhaps a reasonably realistic approach to working and living on Mars for an extended period of time. [Andy] used many elements in the book that NASA has put in place and is pursuing, such as communication [from Mars to Earth] done through orbiters—that infrastructure is there. We would leave the surface of Mars on a MAV; we are developing aspects of MAVs now. We are also developing high-powered ion propulsion systems, Those would be the same systems they used on Hermes to travel back and forth to Mars … So there’s an undercurrent of realism that is really quite refreshing and just delightful for us in the business.

A.W.: I deliberately sacrificed reality for drama with the [Mars] dust storm … In a man-versus-nature story, I decided I wanted nature to get the first punch in. The other deliberate thing I did was to basically hand-wave around radiation issues. That's actually one of the biggest challenges to sending a manned mission to Mars. I just said that in the intervening time they’d invented some kind of material that takes care of it.

R.S.: I never shoot for movie magic. I think that’s the important thing even if you're doing a science fiction movie like Alien: If I hadn’t got that beast right, you wouldn't have had a movie … But there's a bit of cheating here and there. Eventually they all say, well, you're making movies, so we’ll forgive you!