Here’s why ‘The Martian’ author made one major exception to scientific accuracy

“Big things have small beginnings.” That”s a line from Ridley Scott”s “Prometheus,”* but it also aptly describes his latest movie, “The Martian,” starring Matt Damon as an astronaut stranded on Mars.

“The Martian” was a New York Times #1 Best Seller before it became a big budget Hollywood film helmed by one of the greatest sci-fi directors of all time. But even before it was a popular novel, “The Martian” had this surprisingly humble beginning: Its writer, a software engineer named Andy Weir, published the book in serial format, chapter by chapter on his blog in 2011.

What if someone had told Weir in 2011 of “The Martian””s big screen destiny? “I would not have believed it,” Weir assured HitFix. “It”s just ridiculous.”

*and yes, before Michael Fassbender spoke those words in the “Alien” prequel, that line belonged to Mr. Dryden in “Lawrence of Arabia.”

Weir”s book is full of specific math and science that astronaut Mark Watney (Damon”s character) is using to survive stranded on Mars with limited supplies. But even if you”re not a science geek, all those technical details in the novel go down with a spoonful of Watney”s dry, smart-ass but optimistic humor.

Ahead of the film's October 2 release date, HitFix chatted with Weir about seeing Damon embody his MacGyver-esque protagonist, why he made one major exception to scientific accuracy in his novel, what the deal is with the Hermes commander“s disco obsession, and whether Watney”s crew mates would have survived if they had been stranded on Mars.

SPOILER WARNING: Details of the book”s plot lie ahead, but, for now, we”ll stay clear of most details about just how the film adaptation plays out. Check back here on HitFix on Saturday for more from our interview with Weir about the movie.

HitFix: What part of the movie was most exciting or rewarding for you to see realized on-screen?

Andy Weir: What was really cool was just the panoramic vistas of Mars. The beautiful scenery shots, the stuff that Ridley Scott is actually kind of famous for. There”s only so much you can do in a book to describe a landscape. You can say, “Oh, yeah, you know, there”s mountains, and it”s red, and it goes very far.” If you spend too much time describing landscape or scenery, then the reader”s just gonna throw the book over his shoulder “cause it”s boring. But showing it visually on a screen is stunning and beautiful.

Mark Watney is a pro problem-solver. Of course, you had to dream up the problems and also the solutions for all these instances when Mars was trying to kill him. How did you come up with all of that?

Well, I tried to make each problem come from the solution to the previous problem. It”s just the desperate juggling act of resources. Some of the problems are caused by the ways he had to sabotage his own equipment to do stuff. Some of them are caused by the equipment being used well past its intended lifespan. Some of of the problems are caused by his own errors. He makes mistakes. He's not perfect. He screws up. A lot. And he almost kills himself a few times.

You did a lot of research to make this book as accurate and plausible as possible. But you made this one exception with the original storm that separates Watney from his crew mates. Why allow yourself that one exception to accuracy?

For context, a real Martian storm would barely be able to knock over a piece of paper [because] the atmosphere is so thin. The reason I did that was because I needed to get him stranded there. And I had an alternate beginning where all the problems are caused by an engine test failure, like they”re testing the MAV engine and there's an explosion and then a fuel leak, and that ultimately leads to the scenario where they have to evacuate and they think Mark”s dead, etc. But it just wasn”t as cool. In a man vs. nature story, I wanted nature to get the first punch in. The problem was I couldn't find a plausible or realistic way for nature to cause the problem without kind of breaking the rules.

How did you decide just how much to go into technical detail with Watney”s mathematical calculations and scientific problem-solving?

Yeah, it was a constant balancing act. There”s a bunch of information that the readers needed to know in order to even understand the problems that Mark”s having and to understand his solutions. But I didn”t want it to read like a Wikipedia article, right? So I needed to give them just the information that they have to know. Which is hard – as a dork, a science geek, a bunch of this stuff is very interesting to me that is maybe not so interesting to everyone else. So I had to resist the urge to just lay out all of the stuff I know. It”s like, “Hey, it took me a long time to write this. It should take you a long time to read it!” [Laughs] And then there”s the smart-ass narrator, and that helps too because it breaks up the science talk with jokes, and that keeps it interesting hopefully.

What was your involvement in the screenwriting and production of the film?

Mostly my job was to cash the check. But when Drew Goddard wrote the screenplay, while he was working on it, he called me frequently, like pretty much every day for a while, usually with technical questions, but sometimes with character and plot questions. And he wrote an adaptation that”s very true to the book, so I'm really happy with how that came out. And during production they would occasionally send me a technical question. But they weren't really interested in creative feedback from me or anything like that.

Did they consult you at all for casting?

No, they didn”t.

What did you think of the production”s decision to change Venkat Kapoor”s first name to Vincent and have him not played by an actor of Indian descent?

They originally had Irrfan Khan to play the role. He had to back out due to a Bollywood contract conflict with it three weeks before shooting began. They had a very short time to fill the second most important role in the story. Venkat has more lines than anyone other than Mark. And so they were like, “Okay, well we no longer have the luxury of going after a specific ethnicity. We just wanna find a really good actor to play this role. And one who is available right now.” And ended up being Chiwetel Ejiofor. Which is great. He does a fantastic job. So they just said, “Well, the character”s name is Venkat Kapoor, and we”re having him be played by a black guy. What do we do?” So they decided, “Okay, his name is Vincent Kapoor, and he's half-black, half-Indian.”

Do you share Commander Lewis” love for disco music?

I do actually. I am a fan of disco in real life, and my friends all give me s— for it. But I like disco!

So you must have had a fun time with the music chosen for the film.

Yeah. I was the one who suggested “I Will Survive” for the closing credits.

Do you think any of the other Hermes crew members would have survived if it had been any of them stranded on Mars instead of Mark?

I”ve thought about this. After Watney, I think Johanssen would have had the best chance of survival because she is the one most likely to be able to fix the communication system. If she found herself stranded and then survived the initial problems, she would get communications working again and would have all of NASA as a braintrust to solve problems for her. It would be less exciting.

Another hypothetical: What if it was Watney and Lewis? What if they had to leave Lewis behind when the MAV was tipping? Well, now you have Watney and Lewis working together, so that”s good, but the bad news is now it”s double calorie consumption. I put a lot of thought into that, and then I was like, well actually, if they launched without Lewis, they would know that Lewis was still alive on the surface, so they would not leave orbit. With Lewis stranded on the surface, Martinez would be in command, and there's just no way he would leave orbit if he thought Lewis was still alive, so they would immediately start working on that. And remember MAVs are remote piloted, so Martinez would take remote control of the Ares 4 MAV and have it launch from Scaperelli and have it land at the Ares III site. Then they”d need to generate more fuel. So Watney and Lewis would need to survive long enough to generate more fuel for the MAV because it would have used a bunch on that translation. But then they”d launch up into orbit, rendezvous with Hermes and go home.

Watney”s an interesting character in that he doesn”t actually change a lot through the course of the book. You”d think that kind of experience would change a man – but he stays pretty constant in his persistence and his humor. Why that approach to the character instead of having him snap and go mad or get depressed after all this time in this lonely, treacherous existence?

That”s just not the story I wanted to tell. It could have been a dark, depressing story of a man”s struggle against crippling loneliness and constant stress, and it could have been him on the verge of insanity all the time and barely managing to keep his s— together. It could have gone that way. But I just wanted MacGyver on Mars. I wanted that scene from “Apollo 13” where they make the Lunar modules air regulation system with the command modules CO2 scrubbers. I wanted a whole book of that. I don't want deep, psychological decompression scenes or anything like that. I want constant, interesting problem-solving. I just said, “Well, he's not a normal person. He's an astronaut.” He beat out tens of thousands of highly qualified applicants for this job. Why? Because, among other things, he's really good at handling stressful situations, and he's really cool under fire. 

How long do we have to wait to read your second novel?

I”m working on my next book now. It's tentatively titled “Zhek.” It should be out in late 2016. It”s a more traditional sci-fi novel. It has aliens and faster-than-light travel, but done my own way. I invented my own tiny bit of bulls— physics that enables faster-than-light time travel, and I tried to make it so it doesn't conflict with real physics anywhere.

Anything you can tell me about the story or the characters?

Um. No, that”s as far as I”ll go on that.

If you were stranded on Mars, would you make it?

Nope. There”s just no way I”d be able to handle that stress.

Even though you”re a pro problem solver like Watney?

Yeah, I”m a great problem solver when it”s just some fictional character”s life on the line.

“The Martian” opens in theaters on Friday, October 2.