Andy Weir and Drew Goddard have been enjoying the success of Fox’s “The Martian,” which has notched seven Oscar nominations (including best pic and screenplay) and $608 million at the box office. The writers of the novel and screenplay, respectively, have said they hope the book and movie inspire people to get more passionate about science. The scribes spoke to Variety about the relationship between author and adapter.

When did you two first talk? Was it when Drew signed on?

Drew Goddard: I think it was March or April of 2013. I signed on pretty quick. I got sent the book and read it many times over three days and said “I’m in.” Shortly after that I called Andy, mostly to tell him how much I love the book.

How often did you talk during the scriptwriting process?

DG: At first I said to Andy, “Let me tell you what I love about the book” and we had a couple general conversations about that. One of the challenges was what to cut. Andy, in one of our first conversations, laser-focused on a section in the back half that could be condensed and that was when I thought, “Alright, we’re on the same page.” At some point I told him I was going to have to go into a cave for a while and make hard decisions and I knew as a fellow writer he wasn’t going to want to listen to me second-guessing things that were very dear to him.

Andy Weir: Mostly our interactions while he was writing it were technical questions. He’s a very creative guy, he doesn’t need my help on any of that, but he was asking, “What about the math on this? Explain how this chemistry works.” He also had a bunch of battles with the studio and it’s amazing how important it seems when you’re in the middle of it and when you step back and look, you realize it wasn’t that huge of an issue.

DG: That’s true but it does seem in the moment, when you’re working on it in the trench, it does seem like everything.

AW: The big thing for me, and a battle that Drew won, was they didn’t like the fact that Mission Control was in Houston but the launch center is in Florida, which is how it is in the real world. They were like, “Let’s just have it all in Cape Canaveral.” I remember being like, “Please, Drew, for the love of God, give up on anything else but keep fighting on that.”

Andy, was there anything else from the novel that you wanted to include or thought could be condensed?

AW: The biggest point of agreement was the big chunk of the book that could be cut. It’s when Mark travels from the Hab to the Ares IV MAV. A lot of stuff happens in the book on that trip and Drew said they were probably going to montage that.

The one thing I was really sad didn’t make it into the movie was the Aquaman joke. There was a silly Aquaman joke that did make it into the promotional content but not the movie. The Aquaman joke was like my second favorite gag in the book.

DG: I think we probably overthought that one and if we could go back we’d probably put the joke in.

AW: No, no. Every now and then I think why the joke didn’t make it in and then I think of the context of where we were and I remembered you needed to introduce the running gag for the disco music.

DG: That was it. That was the challenge of the screenplay; every scene had to do four different things. We had to get the science in it, we had to get the humanity in it, you to explain what was going to happen to the audience and you have to set up the next scene. It becomes a zero-sum game of “I only have so many words per scene.”

Andy, was it difficult to let go of the project? And Drew, was it hard to take Andy’s story and do your own thing?

AW: At that point it was a very speculative project. We didn’t have Matt [Damon], we didn’t have Ridley [Scott], it was just Drew, who was originally planning to direct it himself, and it was so speculative that it didn’t really feel real. I didn’t feel like the stakes were very high. I would have given it a 1,000 to one odds that it would even get made.

DG: We talked about the odds a lot.

AW: Everything fell into place after the period where I would have been worrying about it. If things had gone differently, like, “OK, my book’s a bestseller and the studio wants to buy the rights outright and we’re definitely making this movie, we’ve got these people attached, it’s going to happen and Drew is writing the screenplay,” then I would have been nervous.

DG: That’s true. I hadn’t really thought about that, but we really benefited from the fact that we were such on the periphery of the studio. No one was really paying attention to us. Nobody cared. The book hadn’t come out in published form yet, it was still just an e-book and an audiobook. It was just a weird project we were working on.

The thing that is really hard about adaptation is that I try to only pick things I love because if it is something where you think, “Oh, that sounds like an interesting idea but I don’t love it,” then I can’t do my job well. What’s hard is you have to love the book and you have to break the book’s heart. I think I wring my hands more over protecting the book than Andy does. He has been so sweet and supportive about changing things and I’ve been saying, “I don’t want to change anything unless I have to because I love it so much.” I do know that the best way to make a mediocre movie is to just transcribe the book. They’re just two different things.

What were your reactions when you finally saw it on the big screen?

AW: I cried. Fox brought me here to watch it in a viewing room and most of the special effects weren’t in so it was people hanging on wires and green screens and stuff like that and I didn’t even care. That opening scene where it pans down on Mars and the title placard comes up and I thought, “OK, they really did make this. They were telling me they made it and they were sending me pictures from the set but here it is. All these characters I just s–t out of my brain are really here.” It was pretty emotional for me.

DG: I remember the first couple of cuts I saw, all I could see were my mistakes. We fixed them but at the time I thought I had ruined my own existence and all I could think was, “Oh my God, Andy is going to be so mad at me.”

I was sitting in on the third screening and I had this moment where I realized I wasn’t paying any more attention to the question of how I make the movie better and had just given myself over to the movie. It was at a test screening and the lights came up and Ridley and I glanced at each other and said, “No, it’s good.” Ridley went, “Let’s get out of here and have martinis.”