How I Wrote... The Martian (and how Hollywood turned it into a film)

Self-published author Andy Weir on going from blogger to blockbuster

For 25 years I was a computer programmer, quietly sitting in a cubicle writing code, and suddenly I’ve been thrust into this world with movie stars and NASA people – it’s been a complete upheaval of my life but it’s been awesome.

I’d been poking around in my head at the idea for The Martian but I didn’t really do anything with it for about four years. I’ve been a big fan of space and the space programme for my whole life - it’s always been a hobby and an interest of mine - so I started off with more than a layman’s knowledge, because I eagerly watch any documentary on the subject. But it’s not like I researched everything in advance – I did that as I wrote it.

My brand of self-publishing was just posting things for free on my website, and I’d accumulated a mailing list of about 3000 hardcore science nerds – just like me – over 10 years of writing science-fiction stories. So when I got to a part where I needed to know how ion thruster engines worked, I’d do the research, post that part of the story and then get feedback from the mailing list.

There’s a guy on the list who works as a reactor technician and he emailed me information about radiation; another guy’s a chemistry professor and he told me I’d got some of the science wrong in one of the chapters. It was like having 3000 fact checkers – I called them beta readers.

The hardest part was explaining all the scientific stuff to the reader without it sounding like an encyclopaedia – that’s why Mark is a smartass and uses all that gallows humour. I’m also a light-hearted guy, so two or three jokes per page keeps pulling the reader through. I didn’t want the reader to be too heavily focused on the date. I wanted it to seem like it was true, but at the same time I wanted it to feel like it was happening now, so I mentioned things like Wikipedia early on in the story to make it feel contemporary.

20th Century Fox got advisors at NASA and its Jet Propulsion Laboratory to keep things realistic for the movie. Ridley Scott [the film’s director] cares a lot about scientific accuracy, which is great, because that was a priority of mine - but it wasn’t necessarily going to be a priority of his. I could tell from the deeply detailed scientific questions that would filter down to me from him that he was paying a lot of attention to accuracy.

I haven’t seen the film yet, but the trailer matches what I had in my head very, very closely, especially the video that shows Matt Damon talking to the psychiatrist. He has nailed the character – it’s perfect. The Hab, where the astronauts live while on Mars, is exactly the way I imagined it. The spacesuits are more sci-fi than I had in mind but I think they look awesome.

Hermes, the ship they take to and from Mars, looks totally different to how I pictured it, but I never really described it in the book so that’s understandable – and I think it looks great.

NASA is very happy with the book and they’re really excited about the movie. I think they see it as a way to hopefully re-engage the population in space travel.