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Photo: 20th Century Fox

Filled with technical details on hacked-together and makeshift survival solutions, The Martian follows the story of astronaut Mark Watney’s struggle to stay alive on Mars after being abandoned and left for dead by his crewmates. It explores practical applications of chemistry, electronics, physics, as well as the mindset of a never-say-die Maker/astronaut (played by Matt Damon in the upcoming cinematic release), all with clarity and humor.

This interview of best-selling author Andy Weir by MythBusters star Adam Savage was originally created for Tested.com’s series The Talking Room.

You can find the full interview, along with every episode of The Talking Room, here.

Adam Savage: Talk to me about the genesis of this book.
Andy Weir: Well, I’m kind of a dork, and I really like to sit around and think about the space agency and space program and manned and unmanned spaceflight. I was thinking, how could we do a manned Mars mission with the technology we have right now? What would it entail, how do you get people to Mars, how do you get them to the surface, how do you get them back up? So I came up with what’s basically the Ares mission as described in the book.

AS: So is the book the end result of an exercise in your head of “How will this be possible, and what would happen?”
AW: Yeah. I was basically saying, OK, how would we put together a Mars mission the way I want to do it? [It is] a manned mission, so you can’t just have a failure kill the crew. You have to say, what happens if this fails? How do you ensure the crew
survives? How do you abort at this point in the mission?

AS: So in each of these things you’re trying to think like NASA would think it terms of worst-case scenarios, and you’re going through space history to see how NASA solved these types of problems in the past?
AW: Absolutely. The fun part is thinking of a problem that’s never been solved, and what can I do to make sure it gets solved? What if they have to abort when they’re halfway to Mars? What if they have some critical failure on their ship? Is there an orbital trajectory that just brings them back to Earth fairly quickly with-out ever going to Mars? So I was working on all that and I thought of all these things that could go wrong on the surface. This could break, that could break, these two things could break at the same time, how do we deal with that. And then I started to realize the increasingly desperate solutions, and I thought, “Well, theoretically they could survive if they did this and that,” and I realized that makes for a pretty interesting story.

So I created a poor hapless main character and subjected him to all of them.

AS: Is there a history of a certain mission from NASA that helped really inspire or guide your thinking?
AW: Obviously, Apollo 13. My favorite scene in the Apollo 13 movie is when they’re making the CO2 scrubber adapter.
Basically the “mailbox” it was called. That’s one of my favorite scenes of any kind in cinematic history. And so basically I wanted to make a whole book of that. That’s what I was going for.

AS: Was there a point in which you were writing, thinking through what could go wrong and how would you fix it, where you went to a dead end? Where you went down a path that was just too difficult to fix and you backtracked?
AW: Yes, that actually happened a few times. I would always start with the problem and say, “OK, how does he solve it?” I wanted each problem to come from the solutions to the previous problem. The whole book I wanted to be kind of a cascade failure. I wanted each thing to lead to the next.

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The Martian author Andy Weir. Photo: Hep Svadja

A Space Dork’s Library

AS: The thing that I find surprising is the way you cover the astronauts. I know that there’s lots in the literature of NASA about their evolving understanding of the personality type that makes a good astronaut.
AW: The astronauts are just universally acknowledged as a cut above the rest of humanity. They’re just so awesome, and you say, “What makes a good astronaut?”

If you’re going to have a mission that’s going to take an entire year from start to finish, you’d better have six people who work together. I usually don’t like it when I’m watching a movie or reading a book and there is a crew, and they have this tension and these personal issues and stuff like that. I’m like, “No, astronauts are unbelievably professional.”

So the things I wanted to do for the crew are, first off, obviously everybody is extremely good at their technical skills. Everybody knows exactly what they’re doing. Number two, a very good esprit de corps. They have no personal issues, no arguments or problems with each other, they don’t butt heads on anything. They’re really professional and they get along very well. Then third, a deep and profound confidence in their commander. Commander Lewis, nobody ever questions what she has to say, ever, and not because they’re afraid of her, but just because they respect her that much. They have complete faith in her. And you need that in a crew of anything from a fishing boat to a spacecraft.

AS: Is your reference library like 20 books or 100 books or 500 books?
AW: It’s one computer. I just Google around to find what I want and then make sure I get good sources.

To be fair I should point out that [the mission is] about 95% Mars Direct by Robert Zubrin. His concept was to send a ship to Mars and then make fuel using the Martian atmosphere. It’s called In-Situ Resource Utilization.

AS: OK, and that saves a tremendous amount of payload into getting stuff there.
AW: Right. That’s roughly what Zubrin’s idea was.

He came up with that before ion engines existed. [In The Martian, the spaceship that goes from Earth orbit to Mars orbit uses ion engines. The surface-to-space vehicles, however, use traditional rockets.] Ion engines are real technology. They’re not just invented for the book. Basically they’re particle accelerators that shoot argon out very, very fast, so fast that the particles gain relativistic mass.

AS: Oh, wow. This means that it accelerates very slowly, but consistently over a long period of time?
AW: A very long time, and you need a lot of energy to do that, so you need a reactor aboard. Then you accelerate the ship at two millimeters per second per second, so it would get going faster and faster. If you do that for months, you end up going very fast. You need a delta-v of two and half kilometers a second to put yourself on a Mars intercept, which is 2,500 meters per second, which is about 5,000 miles an hour.

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Photo: 20th Century Fox

Down to the Day

AW: So I made this simulation, and naturally I had to have a launch window. I needed to know the locations of Earth and Mars. I had to calculate this trajectory where you have Earth moving, Mars moving, and then my ship trying to match speeds and location with Mars.

AS: So did you choose a year then?
AW: I had to choose a specific date.

AS: This is so great! This is exactly the kind of level of detail I go into with my projects.
AW: Well, because of plot reasons the originally scheduled mission has to overlap Thanksgiving. So I had to choose a launch date such that they will be there on Thanksgiving of that year, and Thanksgiving floats around, so that’s kind of a pain in the ass.

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Photo: 20th Century Fox

Feedback from the Pros

AS: Let’s go back to the first time a NASA engineer writes to you. It’s probably before the book is published, right? Is there somebody who’d worked at NASA that sort of came across the book?
AW: Yeah. I mean I had people who are engineers, scientists, and people who work for NASA or JPL would send me email with either critiques or, “Hey, good job.” The ones that I really liked are the ones where they sent “Hey, you got the math wrong,” because then I feel really good about it because it’s been double-checked.

There is one scene early on in the book where Watney is reducing hydrazine to liberate the hydrogen, and then he’s burning the hydrogen with oxygen to turn it into water. This does not go as smoothly as he’d like … but the point is he does end up reducing a certain amount of hydrazine and turning it into water over a certain period of time.

I got email from a chemist saying “OK, you tell me how much hydrazine he changed and how much water he made, which is correct,” and he said “but you’ve also in the past told me the atmospheric pressure of the habitat, and the general dimensions of the habitat, from which I can calculate the volume, and you told me how long it took him to reduce all these hydrazine. It’s extremely exothermic to do that reaction and from that I can calculate ….” Basically he had enough information to calculate that temperature increase in the habitat that would happen as a result, and it’d go up like 400 kelvin, so Watney would have died. He would have like roasted himself alive. I didn’t find out about that until after it was already in print, so I can’t fix it. But I like this guy.

AS: Tell me about your first interaction with an astronaut. That must have been exciting.
AW: I wish I could remember his name. He was a space shuttle astronaut. He said, “I really liked your book and stuff, but just so you know you can actually bake the CO2 out of lithium hydroxide canisters by heating it up.” I didn’t know that. There is this whole part [in my book] where Watney has to bring the oxygenator with him on his long trip. If I’d known you can just bake the CO2 out, that would have been much simpler.

AS: Are you writing another book right now?
AW: I am. I’m working on my next book; it’s called Zhek, it’s a working title, and it’s more of a traditional sci-fi. So it’s not rigidly scientifically accurate, it’s more soft science fiction, like aliens and stuff like that going on.

AS: I can’t wait to read it.
AW: Well, thank you.

Check out more about Andy Weir on his website.