The Science (and Math) of Andy Weir's Sci-Fi Success

Posted by Cybil on April 29, 2021
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Andy Weir takes his readers on interstellar journeys that explore science, survival, and the solar system. His characters have been stranded on the desolate reaches of Mars and lived in the first colony on the moon.
Weir’s latest book, Project Hail Mary, goes even farther, beyond our solar system, to planets that are known but not explored. This time, the mission of the crew is a one-way trip to save the Earth from extinction.
Ryland Grace wakes from a scientifically induced coma aboard the spaceship the Hail Mary. He’s light-years away from Earth, with no memory of who he is or why he’s on the ship. The two other members of Grace’s crew have died on the voyage, leaving him to slowly piece together his past and his purpose through a series of flashbacks.
Grace comes to remember that the sun has been infected by an extraterrestrial life form of space algae. This unintelligent life form, astrophage, is stealing light from the sun and all of the stars in the galaxy—except for one. Grace must find an antidote to astrophage and send it back to Earth.
Though literally on a suicide mission, Grace finds friendship and hope when he encounters another spaceship circling the star. Onboard, he meets Rocky the alien, who was sent to save his home planet from a similar fate. Together, the two must find a solution to save both of their worlds.
For Andy Weir, the fun of writing is in the research. He spoke to Goodreads contributor April Umminger about striving to become a better writer, the process he used to create a beloved alien, and how he comes up with the ideas for his books. Their conversation has been edited.

Goodreads: Before we dive right in and talk about your latest book, Project Hail Mary, it strikes me that you are a very prolific writer. Do you already have the idea for dozens of books in your head or in various stages of completion?

Andy Weir: More or less. I have my ideas file, and whenever I think about something, I throw that in there. But that doesn't mean that they're good ideas. The trick is, when I'm deciding on a new project, to determine which of these ideas are awesome and which of them are just stupid.
For instance, one of my ideas is a story where the main character appears to be a guy who is very lucky—all the time. But it turns out that he’s not lucky; it’s his cat that’s lucky. It’s all about the fact that his cat is really lucky, and because his cat likes him, then he is lucky. I would title that Felicitous Feline or Fortunate Feline.
That was in my ideas file. And we’re not going to do that.

GR: There is a certain demographic that would love that book. How do you make the call between the ideas that are good and those that are not? Is that where the idea for Project Hail Mary came from?

AW: It’s a subjective call, but I think Felicitous Feline, safe to say, is not a winner.
Most of my ideas come from me speculating about cool science stuff. For The Martian, I thought, “How could we put humans on Mars and get them back safely?” I wasn’t even thinking about a story. I was thinking, “How do we do this? How do we make sure people get there safely? And what happens if this breaks? What happens if that breaks?”
Then I realize that this is starting to sound like it might be an interesting story.
For Artemis, my thought process was, “What is humanity’s first city that is not on Earth going to be like? What's it going to be like, and why would anybody bother to build a city somewhere other than Earth?”
That’s often how I end up doing what I do. I think of something cool and scientific, and then, if it gets interesting enough, I think, “Oooh, I can make a story around this.”

GR: What was the line of inquiry for Project Hail Mary, then?

AW: For Project Hail Mary, it kind of worked that way, but it's also made up of spare parts from other story ideas.
After The Martian, I had this idea for this massive space epic—a traditional sci-fi pilot with aliens, faster-than-light travel, and telepathy and a war and, yeah, a ten-book series and everything.
I worked on it for about a year; it was going to be called Zhek. I got 70,000 words in, and—for reference, The Martian is 100,000 words—I realized that it sucked. It wasn’t interesting to read. The characters weren’t compelling, the story meandered.
From that, I wrote an entirely different book, Artemis.
But there are a few nuggets in Zhek that were solid. There was one interesting character who was this absolutely no-nonsense woman with a ruthless drive to get what she needs to get done and a tremendous amount of secret authority.
And she became Stratt in Project Hail Mary.
The other thing is, in Zhek there was this substance called black matter, which was a technology invented by aliens that would absorb all electromagnetic waves, all light, and turn it into mass and then turn it back into light. It was the perfect interstellar spaceship fuel.
I started speculating in that direction. This substance, it's just this magical, alien technology that is basically turning energy into copies of itself. Then I asked, “Where does it get that energy, and why does it need it?”
Both of those things, I came up with the answer in a shower thought one day. It gets the energy because it doesn't live on planets; it lives on the surface of stars. It needs the energy because it spoors out to other stars, like mold. It needs that energy to propel itself.
My next thought was that if humanity got ahold of some of that, it would be neat, but it would suck if we accidentally let any of that get into the sun—that would be a disaster.
I'm like, “Wait a minute, that would be a disaster! That's where books come from!”
Instead of humanity acquiring it accidentally, they discover it because it has already infected the sun. That all fit together well. And since it's also this perfect spaceship fuel, then I want the characters to use this.
I want the problem to be part of the solution. And it all just started coming together.

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GR: What was your process? How did you do your research? How did you work out the science? And how long did it take you to get this story together?

AW: I say it took me about a year to write the first draft. My favorite part of writing is the research, and the math, and the figuring all that stuff out. Characters and plot and stuff that I am required to do for a book—that’s unpleasant.
How I do my research is Google. People assume I have a contact list full of NASA engineers and Nobel laureates who are happy to help me out, and I do, but Google is faster.

GR: Does Google ever get it wrong?

AW: Oh sure. But it's more a matter of “do I trust this site?”
Science information is very well represented on the internet, and it's generally not really a controversial topic, aside from the occasional anti-vaxxer or flat Earther or moon-landing denier. It's not like there are a lot of different opinions on how heat differential equations work.
It is what it is.

GR: Your main character, Ryland Grace. What the inspiration behind him and creating a lead?

AW: I developed him as a character in an attempt to develop myself as an author.
I am considered a very good writer—but not by me. I have never really considered myself that good a writer. I lack a lot of skills that, I feel, better authors have, and I want to acquire them.
One place where I consider myself very weak is in character depth and character growth. For instance, in The Martian, it's an entirely plot-driven story. You don't know anything about Mark Watney through the whole book. All you ever know about Mark Watney is he's kind of a smart-ass and he doesn't want to die.
That's the extent of his character—you know nothing else about him. You don't know anything about him, and he undergoes no change throughout the entire story. He doesn't become a better person. He doesn't learn a lesson. Nothing. He's exactly the same at the end of the book as he was at the beginning. There's no character element other than a likable everyman in a bad situation.
I feel like I got away with something in The Martian. I don't know why the entire world loved 360 pages of algebra questions. But they did. They probably won’t again.  
When I was working on Artemis, I made a very different character lead in Jazz Bashara.
Now, Mark Watney is the idealized version of me. He has all of the traits that I have that I like about myself magnified, and none of the traits that I have that I don't like about myself.
I'm pretty smart; he's really smart. I'm kind of snarky; he's funny as hell. I can be resourceful at times; he's incredibly resourceful, and he has none of my fears and neuroses.
Jazz Bashara is more like the real me. She has the same flaws I had when I was her age. She is basically immature for her age, not really living up to her potential, always looking for an easy way out rather than doing the work to get things done the right way, and being her own worst enemy, causing a lot of her own problems.
I wanted to make a character who was complicated and deep and flawed in Jazz. She, throughout the book, undergoes growth and becomes a better person by the end. But people didn't really like her that much. My personal analysis on it is that they just had a hard time rooting for Jazz.
What I learned is that Mark’s the idealized me, Jazz is the bad aspects of me, and people like the idealized me more than they like the flaws that I have.
Ryland Grace was my first attempt to make a protagonist not to be based on me. He's a unique character I'm creating from whole cloth, and so I'm not limited by my own personality or experiences.
That's my attempt at growth as a writer. I wanted to make a character who was not based on myself, who was created to be a good match with the story that's taking place. I'm just always desperately trying to get better at what I do.

GR: That's very humble of you. I want to talk about Rocky. He’s got a very special shape. Without giving too much away, how did you arrive at that and did you consider other physicalities when you were making your alien?

AW: The thing that has driven me absolutely batty crazy angry is that science fiction always has aliens perfectly comfortable in Earth's atmosphere, temperature, pressure, radiation level, etcetera.
I decided I was going to go out of my way to make things as incompatible as possible.
These aliens have a really thick atmosphere—29 times our atmospheric pressure. Venus has 90 times our atmospheric pressure, so it’s well within things we’ve seen. Then I decided that atmosphere was entirely ammonia with no free oxygen.
Functionally, this planet would be kind of like living in an ocean. Like the deeper you go, the darker it gets. By the time you get down to the surface where the intelligent life live, it's pitch dark—day or night, pitch dark. Then they would not have evolved sight.
I got to have a lot of fun with that. Each little thing, I started by defining things about the planet, and figuring out more things about the planet, and then ending with needing a life form that evolved to live in that environment.
Additionally, all of the planets in Project Hail Mary actually exist. Adrian and Erid are both real exoplanets. Planet Adrian is actually Tau Ceti E, and Erid is—the star is 40 Eridani—and the planet designation is “B,” I think.
We don't know a lot about these planets except their mass and how long it takes them to orbit their star. I picked this planet, this exoplanet, in orbit around 40 Eridani. Then I asked, “What do we know about that in the real world?”
It has an orbit around Eridani of about 46 days. It's very close to its star, and it goes around fast as a result. And it is very large—like, eight times the mass of Earth. It could be gaseous or rocky, but I get to arbitrarily decide that it’s going to be rocky.
Next, I decided the planet has about the same density as Earth and that it’s got a metal core and is made of rock. Then I figured out how big it would be and calculated that the surface gravity would be about two Gs.
Based on that, I figured that the aliens that live there would be strong because they move around in two Gs. I decided Erid is spinning so fast that it can be that close to its star and still have an atmosphere.
At that point, what I've learned is that the aliens who live there live in two Gs and their day is about six hours long. They're small and they're very dense and they're veeerrry strong.

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GR: You were talking about character development. What was your process for making this alien lovable? Rocky is such a good alien.

AW: People ah-dore Rocky.

First off, it’s very quickly established that he's a good person. He's in the same boat as Ryland, and he's also sad and lonely because his crew died. You feel bad for him. You can really empathize with him.
Rocky also is as intelligent as an adult human, but due to the language barrier, he comes off as childlike. I think people like Rocky in the same way that they might like an adorable kid.
Once again, this was an unintentionally beloved character, just like Mark Watney. I did not realize how much people were going to love Rocky until I started getting early reader feedback.

GR: A very smart, adorable kid…

AW: Or a dog. The deep, dark secret is that this book is a buddy road comedy, like Bob Hope and Bing Crosby movies of the old days.

GR: That struck me as well. The book is about so many different things, but really, primarily, it's a story about friendship.

AW: It is absolutely about two people who were extremely unlikely to ever meet not only forming a bond of cooperation, but friendship to the point that each of them is prepared to sacrifice their life for the other.

GR: I was a little surprised by the conclusion of the book. Did you know that you were going to end it that way from the start or did it surprise even you when you landed on it?

AW: I have seen this on (lowers voice) Goodreads reviews that a lot of people are like, “Eeeeeh, I don't know about the ending.” But about halfway through the book, I decided that was how it was going to end, even earlier than that.

GR: What about the title? It is the name of the ship and pretty straightforward in the meaning of the expression. Were there others in consideration?

AW: No, I always had in mind for it to be some sort of variant on the phrase “Hail Mary,” because in American football, that’s the last-ditch pass attempt to save the game. Within the concept of the book, it's called Project Hail Mary because it's the pass where scientists are desperately throwing a spaceship at Tau Ceti to try to save the world.
It’s caused a lot of headaches with the translators. Nobody outside the U.S. knows this phrase. Even English-speaking countries like the U.K. don't have that expression. In most of the language translations, they're changing the title. In one of them it’s just called The Astronaut or something like that.

GR: In science fiction, what writer or stories give you inspiration?

AW: I am a generation off. For me, my holy trinity are Asimov, Heinlein, and Clarke. That's my crew.
I grew up reading my father's science fiction collection, who was a teen and tween in the late 1950s, early 1960s. He was getting the science fiction books with teenagers as the target demographic. I read those books when I was a tween and a teen in the 1980s.
Also, lesser known but still very beloved by me is Clifford Simak’s The Werewolf Principle.
The Werewolf Principle is complicated to describe, but basically a bunch of different alien life forms all end up sharing a single body. The result is all their minds are all together, and whichever one is in charge, whoever’s body they're exhibiting at the moment, is the one who's controlling the body.
If it is the human’s body, then the human is controlling all the motions, but he can hear the other minds talking to him. And when they turn into one of the aliens—they turn into a wolf or something like that—the human feels like he's just out there in a fog. He can see everything and sense everything the wolf is sensing, but he's just part of the committee that's advising the wolf.
Something about that really appealed to me—this idea of never being alone. When I was kind of a lonely teenage kid and didn’t have many friends, the idea of literally never being alone really appealed to me.

GR: And then, what books are you reading now?

AW: Right now, uhm, nothing… [Laughs.].
But books I have read recently-ish that I would recommend to anybody include Recursion by Blake Crouch and The Last Human. Zack Jordan is the author.
Recursion has time travel, and that's my absolute favorite plot of any kind. Blake did a fantastic job of it. It's just a really good time travel novel.
As for The Last Human, it was a good, old-fashioned, pulpy sci-fi. It reminded me of the science fiction of that golden era—the '50s and '60s—but without all the blatant sexism.

GR: Then before I let you go, what is your favorite thing about this book?

AW: There's a saying I have, which is, “Give a man a book, you entertain him for a night. Teach a man to write, you give him crippling self-doubt for life.”
This is the first time that I've written something where I'm pretty confident about it right out of the gate.
I write stories intended to make you feel good. I'm pulling on your heartstrings, blatantly and unapologetically, and I feel like it really came together. What I like the most is how it is a book about friendship.


Andy Weir's Project Hail Mary will be available in the U.S. on May 4. Don't forget to add it to your Want to Read shelf. Be sure to also read more of our exclusive author interviews and get more great book recommendations.

Comments Showing 1-40 of 40 (40 new)

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message 1: by Stephanie (new)

Stephanie Actually, I'd read Felicitous Feline. It also sounds like it'd make a really good short story or novella, not necessarily a full length novel. It'd actually be great as a children's series or a comic.

Marc *Dark Reader of the Woods* Just name it Cat's Eye and give it to me.

message 3: by Joy (new)

Joy Please write Felicitous Feline, I will give you all my money.

message 4: by [deleted user] (new)

"all of the stars in the solar system"??????

message 5: by Kate (new)

Kate Kulig Thank you for the interview.

Also, I liked Jazz a lot. I thought Artemis was a fabulous book. She felt very real to me.

message 6: by Dianne (new)

Dianne I really loved The Martian and I’m so glad that it was made into a movie. I’m looking forward to reading Artemis (also the name of our little cat) and Project Hail Mary. Thank you for writing “science“ fiction. You can now carry on the work of our favourite, but not with us any longer, science fiction authors. Thanks, Mark!

message 7: by Norma Iris (new)

Norma Iris Dear Mr. Andy Weir,
I bought The Martian dvd and will buy the book.
Just one thing about the movie, when Mark Watney is shaving the wooden cross for kindling, he holds the crucifix with Christ on it and believe it or not, actually made a prayer to get him back home, even if in jest. He got home, Hope.
The scene when he's finally on the stripped down capsule, and all on the rescue vessel check in, Watney reports in but with suppressed tears, and then lets out with tears of joy and a big smile of gratitude for his friends coming back to get him home, and a somewhat nod to God for those wood shavings. At least that's what I believe that made me cry. I still can't get past that scene.
Looking forward to reading the book and Artemis.

I remain,
Norma Iris Montalvo (b. 1955)

message 8: by Satvika (new)

Satvika "What I learned is that Mark’s the idealized me, Jazz is the bad aspects of me, and people like the idealized me more than they like the flaws that I have."

Awww don't say that..i like Jazz , i can't wait to read Project Hail Mary

sends lots of love from Bali

message 9: by Brittany (new)

Brittany I loved Rocky and loved the ending of Project Hail Mary! I already pre-ordered “Project Hail Mary” some weeks ago, look forward to listen to Ray Porter’s narration.
Usually I also listen to the German version (“Der Astronaut”) if available.
That would be 3 weeks later according to Penguin RH.

I didn’t read the interview yet because I don’t like to be spoilered. I will read it in a werk after finishing the audible.

kind regards

message 11: by Cybil (new)

Cybil Chris wrote: ""all of the stars in the solar system"??????"

Excellent catch! Thank you and we've corrected this reference!

message 12: by Brandon (new)

Brandon Schumann I'm loving all of Andy Weir's work so far. I like the science, the humor, and the variation between novels. And, who didn't like Jazz? I thought Jazz was a great character, and I was rooting for her the whole way! Alright, adding Project Hail Mary to the list :)

message 13: by Fernando (new)

Fernando Chris wrote: ""all of the stars in the solar system"??????"

Yeah, that did some serious damage to my psyche, lol

message 14: by Fernando (new)

Fernando Felicitous Feline sounds like a Twilight Zone plot and, while not a Pulitzer candidate, might be great fodder if Andy ever decides he wants to do a pulp throwback, maybe as a short story...

message 15: by Pauline Reid (new)

Pauline Reid Extremely interesting, will put it Project Hail Mary on my tbr, good luck with future sales, Andy.

message 16: by RickB (new)

RickB I loved The Martian and Artemis, and I liked Jazz, too. I thought she was a good and believable character, and I am really looking forward to reading Project Hail Mary. Thank you for the interview and the insights on how it develops, and I also think Felicitous Feline has a lot of potential and be a book that I would read. Keep up the wonderful work! Fingers crossed that you do end up writing that space epic.

message 17: by Guy (new)

Guy L. Pace I very much enjoyed The Martian. I’m a little behind, but I’m going to get Artemis and Hail Mary on the list and read soon. Thanks, Andy, for such great work.

message 18: by Miriam (new)

Miriam Felicitous Feline graphic novel when?! :D

message 19: by Grace (new)

Grace Haddon Ohh I'm so excited to read this! Preordered on Kindle already (and the protagonist has my name!). Seconding many others here in that I would also read the cat story :)

message 20: by Clare (new)

Clare O'Beara Thanks for your insights.

message 21: by Elise (new)

Elise Stone There's nothing wrong with a plot driven story. In fact, they're the kind of stories I love most. I also grew up reading science fiction and, like you, "For me, my holy trinity are Asimov, Heinlein, and Clarke."

I was disappointed in Artemis and am a little leery of reading Project Hail Mary (although I probably will at some point). I'll keep an eye out for something more in the vein of The Martian in the future.

message 22: by Chris (new)

Chris It’s an embarrassment that Andy Weir finds it unpleasant to work with plot and characters. I mean, this is what a novelist needs to master. Otherwise just write science articles.

message 23: by August (new)

August Thompson Guess I'm in the minority in that I'm kind of with Weir on "Felicitous Feline." I do think it is a really sweet concept, and I'd definitely read it, but God that'd be hard to write.

message 24: by Erika Schmidt (new)

Erika Schmidt How about "Felix" as a title for a short story/novella, and write it with Neil Gaiman?

message 25: by fasz (new)

fasz I'll be honest with you, Hail Mary sounds incredibly soft (in the science department) and cliché. Like "helicopters to the Moon" soft.

message 26: by Genevieve Plante (new)

Genevieve Plante Now you need write a smart witty cat in your new book. Hail Mary is by far my favorite book and for one really love the ending.

message 27: by Marchele (new)

Marchele Hise Enjoyed Hail Mary. My first thought on finishing was if teachers presented math/science problems in this sort of format, I might have learned a whole lot more. Like The Martian, Hail Mary leans on science & math with the added bonus of imagining how our physical bodies influence how we utilize science.

message 28: by Sam (new)

Sam Ditto about Felicitous Feline--two non-opposable thumbs up....

message 29: by Donalee (new)

Donalee Burns Just finished Project Hail Mary on audio. Loved ever minute of it. Enjoyed the interview. Andy Weir did an awesome job of developing his characters.

message 30: by Michael (last edited May 28, 2021 01:35AM) (new)

Michael Norma Iris wrote: "Dear Mr. Andy Weir,
I bought The Martian dvd and will buy the book.
Just one thing about the movie, when Mark Watney is shaving the wooden cross for kindling, he holds the crucifix with Christ o..."

Creating 'evidence' to confirm your bias no doubt :)
Have a great day

message 31: by Sean (new)

Sean Watson I presume naming your protagonist Grace was a deliberate pun? Hail Mary, full of Grace?

message 32: by Denise (new)

Denise I feel like you’re hitting your stride with each book you write. While I love The Martian and Artemis, I think your writing is stronger in Project Hail Mary. I can’t wait for Felicitous Feline!

message 33: by Karen (new)

Karen I did love the ending. It was unexpected.

message 34: by Phil (new)

Phil Bowman Just finished PHM as an Audiobook, and loved it - the narration, and the conversations both on Earth and in space came over really well - I want to find a text copy to see how the initial conversations with Rocky are written.

My one reservation about the science is that I doubt amnesia works quite that neatly - but once I got to the revelation near the end, it made sense to structure the story that way

The ending felt just right to me

message 35: by Gloria (new)

Gloria The ending was perfect!

message 36: by Nikki (new)

Nikki I loved the ending! I was a bit worried about how it was going to end as it went along, but by the time I got there, it felt so right, like it was the only way. I’ll tell you what, after reading Andy Weir’s books it makes me roll my eyes at how easy everything is for the people on Star Trek. At the same time it makes everything seem doable for us right now if we just get our act together.

message 37: by Vera (new)

Vera I loved snarky, intelligent Jazz. She felt real, very mich like the women around me.
She swears, drinks, breaks the law - while still following her own code.

Often times I can’t relate to the heroine if she is this perfect creature, never doubting her decisions, never being scared, angry or crying. Jazz did all that and I loved that she found a way to get out of her situation without letting Rudy take care of it (while still fantasizing about his strong arms and handcuffs).
Please give us more of those amazing characters!

I also liked Mark. As you said, he is a likeable handyman.

message 38: by Rachel (new)

Rachel Court I loved the ending!

message 39: by Philip (new)

Philip Higgins fasz wrote: "I'll be honest with you, Hail Mary sounds incredibly soft (in the science department) and cliché. Like "helicopters to the Moon" soft."

Yeah, "helicopters to the Moon" duhhh. Everyone knows only flying cars can reach the Moon.

message 40: by Gerardine (new)

Gerardine  Betancourt amazing book amazing interview

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