Dr. Jim Green has been with NASA for more than 30 years — he’s now the agency’s Director of Planetary Science — making him just the guy to help Ridley Scott make his new movie, The Martian, as authentic as possible. We talked with Green about getting that call, science fiction versus science fact, and the Mars generation.

Inverse: To start off, can you tell me about your role as Director of Planetary Sciences at NASA?

Dr. Jim Green: Sure. So I’m the top advocate in the federal government for planetary science. My boss’s boss’s boss is the President. My organization manages $1.4 billion dollars’ worth of assets in the solar system, including all the Mars orbiters and rovers, mission flybys of Pluto — you name it. If it’s not the Earth, it’s mine.

So when did you first hear about The Martian, the book? Were you aware of its unorthodox publication history and its reputation for being scientifically accurate?

What happened was in May of last year, Ridley Scott called NASA headquarters and wanted somebody to talk with about making Mars accurate. He talked to Bert Ulrich, who is the public affairs official for the movie industry that NASA has. And Bert hunted me down at the cafeteria and said, “Could you talk to Ridley Scott at 2 o’clock today?” And I said, “The Ridley Scott?” You know, I was thinking of Alien and some of the movies he did that I really enjoyed, so I said sure.

I spent about an hour and a half talking to Ridley and other people on the phone. We talked everything from ion engines to radio isotope power systems, to artificial gravity and everything else under the sun. They were trying to grasp how they needed to create the visuals in support of the book. At the end of that I realized I only answered about half these questions, so I told them, “Okay, here’s what I need to do. I need to connect you with the right kind of people.”

A week or so later, I organized a tour for Ridley’s team to come to Johnson Space Center. This worked great because then I could answer questions all day long and bring in the right experts, and we just did a ton of stuff. By that time I had read the book and the first script. We also took them to the Jet Propulsion Laboratory. And that just started an intensive period of about four months answering any and all questions that they had.

What kinds of questions were they asking?

Everything from, “What does Mars look like?” “Can we get images?” In that case we gave them a whole variety of images. They asked about when you go into a control room, “What’s on the screen? What are the visuals? What do Mars orbiters actually do? Do they change orbits? How is that done? Can you show that on individual screens?” All that stuff.

You have to recognize that when you read the book you paint the picture yourself. Me in particular, I know Mars. But Ridley’s got to paint it for everyone else on the screen. So they have to know everything! And any detail that they can’t get, they have to create. Once I knew they wanted to make it as accurate as possible and portray Mars and the interaction between the manuscripts that way I was willing to help them in any way I could.

What was it like interacting with the team while they were shooting the movie?

We had to show them everything in whatever time we could, whatever way they needed to. Ridley’s got a schedule and he’s got a budget and he has a solid story. So he’s got to be able to make decisions and not over-design.

Dr. Green at the premiere of 'The Martian' at the Toronto International Film festival.

It’s still science fiction, so when I come into a movie theater, I check my science at the door. You know, I enjoyed Alien too! I must have seen Alien 50 times! But I think this is going to be a great movie and it’s going to be enduring for many years.

I previously spoke to [The Martian author] Andy Weir and he was saying how he doesn’t mind that things in the book could end up being scientifically inaccurate just because we’re getting new information about Mars everyday. He said it’s sort of a treat to be proven wrong in a way.

This is what Andy was telling me: He knew NASA would be making discoveries which might make his book a little obsolete. Which doesn’t matter if things do change and are obsolete because science fiction is enduring. And what’s also great is it allows us to think about our culture, you know, what could happen in the future.

It’s actually easier to grow food on Mars now than when Andy was writing the book. So Curiosity dug in the soil — it’s got a great chemical analysis laboratory, unsurpassed, the most sophisticated experiment we launched and landed on another planet. And that tells us the soil’s got nitrates in it, which is great for fertilizer. It’s got far more moisture in the air. It’s got a lot of water actually in the soils. So in fact there’s a rather extended underground network of water on Mars. All of that makes it easier to get the resources to grow things on Mars.

This is another really great thing about the movie to me because he says, “We gotta science the shit out of stuff.” You’re using your ingenuity and your knowledge to survive. To me, hopefully kids will see that and say, “I want to have some of that knowledge. I want to be creative. I want to know about my physical environment. I want to be able to manage within that.” And Mark Watney does a great job of that.

The story is so science positive. Do you think this story could inspire a fascination with man and space travel for the next generation?

Oh, absolutely. I think the generation today is the Mars generation. For me, I’m in the Apollo generation. I watched the Apollo lunar landing. I know Buzz, I met Neil. All those kind of things are in my era, but in reality, when we landed Curiosity down on Mars, we had the world’s attention. It was just unbelievable and I immediately recognized there is a new generation in town, and it’s the Mars generation. And this is indeed why I think this movie will resonate with a lot of people around the world and certainly the American public.

What was Ridley Scott’s feedback like? Do you remember having to take anything back to him and say, “This isn’t quite how it is?”

They didn’t take every one of my suggestions, and that’s just fine with me. This is still science fiction. You know, and Andy will be the first one to admit it. The dust storm at the beginning the movie is very unrealistic. Half of 1 percent, sometimes as much as three quarters of a percent, is the pressure on Mars from the Earth, so it’s very low pressure. You’d have to be well above Mt. Everest to get the pressure on Earth to be the same as on the martian surface. So even though the winds can be 120 miles an hour, it’s not enough to blow an American flag straight.

But we’ve seen, after dust storms pass, strikes of lightning on the surface. So I suggested instead of the wind destroying the antennae to strand mark on Mars, why don’t you strike it with lightning? And they didn’t do that. They wanted to stay as close to the book as they could. But they did have the lightning. You do see the lightning in the storm as it comes over the hill.

So they didn’t take very one of my suggestions, but they did take the input and created the visuals.

Matt Damon, Jessica Chastain, Sebastian Stan, Kate Mara, and Aksel Hennie in 'The Martian.'

What do you think about the movie’s depiction of NASA, the crew, and Watney? Are there people like Mark Watney among the NASA ranks?

That’s really important — the kind of people that are in it. In terms of all the action, type-A personalities that take charge, you know, they are going to be leaders. But what’s critical is they can also be followers. So that’s a characteristic they have. They also have the ability to have multiple skills. Watney’s background is he’s a botanist. They each have different capabilities.

And in fact when they paired Jessica Chastain with an astronaut, they paired her with Tracy Caldwell Dyson and they got along really well. And Tracy’s a chemist! So these are people that have really great backgrounds that also have rudimentary knowledge in other skills. So while Watney is a botanist, he’s also an electrician. He also understands thermodynamics, he also understands so many of the other fundamental things. He’s a real multidimensional guy. So what I really liked about the movie and the book is it portrays this really well, that man just does a superb job.

And to you that’s representative of the kinds of people at NASA?

Yeah! Exactly. They are all problem solvers. That’s really about American know-how, and American spirit, and being pioneers. It demonstrates the best in all of us in many ways.

The reviews and the general sense of the movie have been really positive so far. Why do you think audiences embrace something like this or like Gravity, where you have to have kind of technically accurate sci-fi?

Well you’re right. It does seem to be that way, that more realistic science fiction is a trend. But there’s always been a niche for that. 2001 had some really fabulous science. Arthur C. Clarke worked in many ways to make his work very accurate.

So science fiction actually has, like anything, shades of gray. Shades of realism and things that are really far out. Interstellar, you know, that’s really far-out. That pushes our understanding from a theoretical point of view of light travel and what we know and what we don’t know about how black holes warp space and time. So that’s kind of esoteric for the bulk of the people that saw it. It just runs that gamut. You have everything from Gravity and The Martian, which try to make everything have the look and feel that’s really realistic to Interstellar, which is really out there.

I wanted to ask about the book and the movie relying on Dr. Robert Zubrin’s Mars Direct method for visiting Mars. Do you think that kind of approach is the most viable option for manned missions to Mars at this particular point?

Yeah, so that’s a good question. Robert Zubrin has been a real forward thinker and Mars has been in his sights for many years. In many ways he’s such a futurist working with Mars and studying the problem about getting there. He’s given some key insight and a lot of it rings true.

For instance, in the NASA plan to feed forward — and that’s part of Mars Direct — you send things there and then you go there after you have everything there waiting for you. You don’t go there and live in a tent until you can build a house. You don’t do that.

This is exactly what Werner von Braun wanted to do with the Moon, for example. He wanted to land a whole series of robots there and from the Earth create structures that then the humans would go and inhabit. So although Mars Direct has those kinds of ideas, they’re not necessarily new. But they are important in the framework of going to Mars as the preferred approach.

One of the things NASA is building right now is a high-powered ion engine. These are the engines that are on Hermes [the ship in the book and film] that allow it to speed up, get the gravity assist from the Earth, and go back to Mars and really make that trip very short in comparison to what normally happens in a 180-day trip there. And we’re developing them right now! They’re part of the Asteroid Redirect Mission. There will be huge ion engines that will be able to pop off a boulder that will carry 50 tons off the surface of a rubble pile that formed as part of an asteroid. That is being designed so that we can take tens of tons of cargo back and forth to Mars. So that’ll be used to drop material off and begin the colony just like Andy described in the book.

Matt Damon science-ing the shit out of Mars.

Do you think you’ll continue your relationship with Hollywood if they come knocking again?

Well actually NASA has interacted with Hollywood on quite a number of things. The Martian is the first time I was directly involved. Partly because I was asked first. But the more I got involved, based on the material they were going to do for The Martian, and the more I thought “Jeez, this is great!” It has so many dimensions about it that I really like. I just got personally involved from that perspective. You know, I have a day job [laughs].

Yes, of course.

I certainly work more than 40 hours a week most of the time. So anything above that is really difficult for me to do, but if I do something new it’s got to be something that NASA approves, and something really good like this.