I read Andy Weir's novel The Martian when it was first released as a Kindle edition. Some time after that I got a notification from Amazon that a second edition was available, which downloaded automatically. However on reading this I couldn't see any difference from the original - which of course I no longer had to compare. What changes were actually made to the book?

  • 8
    In total there have been about 19000 revisions, of which more than 90% are amending numbers or symbols into words (e.g. 200 = two hundred). There are only thirty-three significant amendments involving the addition of a paragraph and only five significant amendments involving the removal or one or more lines.
    – Valorum
    May 9 at 16:13

1 Answer 1


Chapter 1:

  • No major changes, but all the numericals have been made into words ("200" = "two hundred"), all L's have been changed to liters, all % signs changed to "percent", etc.

Chapter 2:

  • There's extra info about Mark's suit.

I’m pretty flush on EVA suits, too. Each crew member had two space suits: a flight spacesuit to wear during descent and ascent, and the much bulkier and more robust EVA suit to wear when doing surface operations. My flight spacesuit has a hole in it, and of course the crew was wearing the other five when they returned to Hermes. But all six EVA suits are still here and in perfect condition.

  • And some extra info about poop as fertiliser.

People have been using human waste as fertilizer for centuries. It’s even got a pleasant name: “night soil.” Normally, it’s not an ideal way to grow crops, because it spreads disease: Human waste has pathogens in it that, you guessed it, infect humans. But it’s not a problem for me. The only pathogens in this waste are the ones I already have.

  • And info about Mark's parents.

I’ve been so busy staying alive I never thought of what this must be like for my parents. Right now, they’re suffering the worst pain anyone can endure. I’d give anything just to let them know I’m still alive.

I’ll just have to survive to make up for it.

Chapter 3:

  • Minor changes to explain how long Mark needs to survive, stressing that food is his biggest challenge in sols/days rather than years.

Chapter 4:

  • Mainly corrected capitalisations of words like hydrazine. "Oh the Humanity!" changed to "My own private Hindenburg"

Chapter 5:

  • Addition of a line about his success thus far.

Looks like I won’t be starving to death on Sol 400 after all. I plopped down in a chair and let my breathing return to normal.

  • Extra line about his hydrazine reaction.

Instead of counting on a clean reaction, I’ll do frequent “hydrogen cleanings” with a small flame. It’ll burn off gradually instead of building up to kill-Mark levels.

Chapter 6:

  • Info about Venkat's office.

His office in Building 1 afforded him a commanding view of the large park in the center of the Johnson Space Center complex. Beyond that, dozens of scattered buildings dominated the view all the way to Mud Lake in the distance.

  • Info about Teddy looking dapper.

Teddy Sanders swept a rogue thread off his otherwise immaculate blazer.... Teddy said, adjusting his cuff links.

  • Info about Venkat looking casual and looking tired.

To have the director of Mars operations visiting SatCon was unusual. Seeing him in jeans and a T-shirt was even more unusual... he asked with the scowl of a man operating on two hours of sleep.

  • Info about Teddy's office.

...glared across his immaculate mahogany desk at his director of media relations. “Not helping, Annie.” ... Teddy moved a folder on his desk slightly to the right so it would line up with his mouse pad. “It is what it is. We have to deal with it.”... Teddy absently rotated the picture to be parallel with the edges of his desk.

  • Info about Annie's thought process before giving her press conference.

THIS WAS going to be rough and Annie knew it. Not only did she have to deliver the biggest mea culpa in NASA’s history, every second of it would be remembered forever. Every movement of her arms, intonation of her voice, and expression on her face would be seen by millions of people over and over again. Not just in the immediate press cycle, but for decades to come. Every documentary made about Watney’s situation would have this clip. She was confident that none of that concern showed on her face as she took to the podium.

  • Additional info about the press corp.

The two stood with countless other NASA managers and executives bunched up on the small stage in the press room. They faced a pit of hungry reporters, all desperate for any scrap of new information.

Chapter 7.

  • Info about why the Hab can spare power cells

and the Hab can spare them. With the reduced load of only supporting one human instead of six, a 14 percent energy production loss is irrelevant.

  • Extra info about Mark's journey to find the RTG

I’m no stranger to Mars. I’ve been here a long time. But I’ve never been out of sight of the Hab before today. You wouldn’t think that would make a difference, but it does.
As I made my way toward the RTG’s burial site, it hit me: Mars is a barren wasteland and I am completely alone here. I already knew that, of course. But there’s a difference between knowing it and really experiencing it. All around me there was nothing but dust, rocks, and endless empty desert in all directions. The planet’s famous red color is from iron oxide coating everything. So it’s not just a desert. It’s a desert so old it’s literally rusting.
The Hab is my only hint of civilization, and seeing it disappear made me way more uncomfortable than I like to admit.
I put those thoughts behind me by concentrating on what was in front of me. I found the RTG right where it was supposed to be, four kilometers due south of the Hab.

Chapter 8

  • Extra info about Mindy's meeting.

MINDY GLANCED nervously around the conference room. She’d never felt so thoroughly outranked in her life. Dr. Venkat Kapoor, who was four levels of management above her, sat to her left.
Next to him was Bruce Ng, the director of JPL. He’d flown all the way to Houston from Pasadena just for this meeting. Never one to let precious time go to waste, he typed furiously on his laptop. The dark bags under his eyes made Mindy wonder just how overworked he truly was.
Mitch Henderson, the flight director for Ares 3, swiveled back and forth in his chair, a wireless earpiece in his ear. It fed him a real-time stream of all the comm chatter from Mission Control. He wasn’t on shift, but he was kept apprised at all times.
Annie Montrose entered the conference room, texting as she walked. Never taking her eyes off her phone, she deftly navigated around the edge of the room, avoiding people and chairs, and sat in her usual spot. Mindy felt a pang of envy as she watched the director of media relations. She was everything Mindy wanted to be. Confident, high-ranking, beautiful, and universally respected within NASA.

  • Added info about Teddy having borderline OCD

He took his seat and pulled several folders from his briefcase. Stacking them neatly, he opened the top one and squared the pages within. ... I like it when people are organized.”

  • Added some info about Mark's thought process

Jesus Christ, I’d give anything for a five-minute conversation with anyone. Anyone, anywhere. About anything.

Okay, enough moping. I am having a conversation with someone: whoever reads this log. It’s a bit one-sided but it’ll have to do. I might die, but damn it, someone will know what I had to say. And the whole point of this trip is to get a radio. I could be reconnected with mankind before I even die.

  • Removed the following passage

Once we got out, Commander Lewis declared “what happened in Missed Orbit stays in Missed Orbit.” It may seem trite, but it worked. We put it behind us and got back to normal.
I’d give anything for just five minutes of Missed Orbit training. I’m really feeling alone lately. Up till this road trip, I’ve been too busy to mope. But the long, dull days with nothing to do really drives it home. I’m further away from other humans than anyone has ever been.

Chapter 10:

  • Extra info about Mark's thought process.

I don’t even know what to say. This was an insane plan and somehow it worked! I’m going to be talking to someone again. I spent three months as the loneliest man in history and it’s finally over.

Sure, I might not get rescued. But I won’t be alone.
The whole time I was recovering Pathfinder, I imagined what this moment would be like. I figured I’d jump up and down a bit, cheer, maybe flip off the ground (because this whole damn planet is my enemy), but that’s not what happened. When I got back to the Hab and took off the EVA suit, I sat down in the dirt and cried. Bawled like a little kid for several minutes. I finally settled down to mild sniffling and then felt a deep calm.
It was a good calm.
It occurs to me: Now that I might live, I have to be more careful about logging embarrassing moments. How do I delete log entries? There’s no obvious way.… I’ll get to it later. I’ve got more important things to do. I’ve got people to talk to!

  • Added info about how slow it is to communicate with Mark.

Sighs of relief and muted conversation replaced tense silence as the image began coming through. It filled out from left to right at a snail’s pace due to the bandwidth limitations of the antique probe sending it.

  • Added info about Venkat's room at JPL and his state of mind.

VENKAT BLINKED his bleary eyes several times as he tried to organize the papers on his desk. His temporary desk at JPL was nothing more than a folding table set up in the back of a break room. People were in and out picking up snacks all day, but on the plus side the coffeepot was nearby. “Excuse me,” said a man approaching the table.
“Yes, they’re out of Diet Coke,” Venkat said without looking up. “I don’t know when Site Services refills the fridge.”
“I’m actually here to talk to you, Dr. Kapoor.”
“Huh?” said Venkat, looking up. He shook his head. “Sorry, I was up all night,” said Venkat. “Forgive me if I’m a little punchy.

  • And the punchline for the joke above. Nobody knows who he is at JPL and keeps asking him about the fridge next to his desk.

“Of course,” Venkat said.
As Jack walked away, a woman approached Venkat’s table.
“Yes?” Venkat said.
“I can’t find any Diet Coke, are we out?”
“Yes,” Venkat said. “I don’t know when Site Services refills the fridge.”
“Thanks,” she said.
Just as he was about to get back to work, his mobile rang. He groaned loudly at the ceiling as he snatched the phone from his desk.

  • Added in some info about the Pathfinder Control room.

A NOTABLE smell hung in the air of the makeshift Pathfinder control room. The ventilation system was not designed for so many people, and everyone had been working every waking moment without much time for personal hygiene.

  • Teddy definitely has OCD

He terminated the call and put his phone on the corner of his desk, flush with the desktop’s edges.

  • Mark gets an email from his mother.

But my favorite e-mail was the one from my mother. It’s exactly what you’d expect. Thank God you’re alive, stay strong, don’t die, your father says hello, etc.
I go read it fifty times in a row. Hey, don’t get me wrong, I’m not a mama’s boy or anything. I’m a full-grown man who only occasionally wears diapers (you have to in an EVA suit). It’s totally manly and normal for me to cling to a letter from my mom. It’s not like I’m some homesick kid at camp, right?

  • Email from the Hermes crew dramatically changed.

Dear Watney: Sorry we left you behind, but we don't like you. You're sort of a smart-ass. And it's a lot roomier on Hermes without you. We have to take turns doing your tasks, but it's only botany (not real science) so it's easy. How's Mars? -Martinez

Dear Martinez: Mars is fine. When I get lonely I think of that steamy night I spent with your mom. How are things on Hermes? Cramped and claustrophobic? Yesterday I went outside and looked at the vast horizons. I tell ya, Martinez, they go on forever!

  • More info added about the water reclaimer and how much water it makes.

Chapter 14:

  • Extra info about Mark's frame of mind.

You know what!? Fuck this! Fuck this airlock, fuck that Hab, and fuck this whole planet! Seriously, this is it! I’ve got a few minutes before I run out of air and I’ll be damned if I spend them playing Mars’s little game.
I’m so god damned sick of it I could puke!
All I have to do is sit here. The air will leak out and I’ll die.
I’ll be done. No more getting my hopes up, no more self-delusion, and no more problem-solving. I’ve fucking had it!

Chapter 15:

  • Extra lines added about the Hab's systems being checked.

  • Seriously, Teddy has OCD.

TEDDY SCANNED the crowded conference room. It was rare to see such an assembly of NASA’s most important people all in one place. He squared a small stack of notes he’d prepared and placed them neatly in front of him.

  • Added an intro for Maurice Stein

Teddy gestured to him and addressed the room. “For those who don’t know him, this is Maurice Stein from Cape Canaveral. He was the scheduled pad leader for EagleEye 3, so he inherited the role for Iris. Sorry for the bait and switch, Maurice.”
“No problem,” said Maurice. “Glad I can help out.” Teddy flipped the top page of his notes facedown beside the stack. “How’s the booster?”

  • More info about the crowd in the JPL cafeteria.

They watched the live feed on a projection screen. Some fidgeted, unable to find comfortable positions. Others held hands.

Chapter 16:

  • The lined below removed from Mark's email to Johanssen

Anyway. Try not to think about all those guys wanking to your poster.

  • The line below added to Mark's email to Johanssen to replace the line that was removed.

Anyway, the point is you’re a nerd. Remind me to give you a wedgie next time I see you.

Chapter 17:

  • Added info about Mitch's encounter with Teddy

Mitch plopped down on the couch in Teddy’s office. He put his feet up on the coffee table and smiled at Teddy. “You wanted to see me?”

  • The word "fucker" repeatedly replaced with "bastard".

Chapter 18:

  • Info added about the control centre in China

He looked through the glass to Jiuquan’s Mission Control Center. It was remarkably similar to Houston’s, though Teddy couldn’t read any of the Chinese text on the big screens.


THE CHINESE had arranged a small conference room for the Americans to work in. The cramped conditions were luxurious by Jiuquan standards. Venkat was working on budget spreadsheets when Mitch came in, so he was glad for the interruption.

Chapter 19:

  • Some extra technical mumbo-jumbo about the AREC

One hitch: I need to put the AREC outside. The imaginatively named “atmospheric regulator external component” is how the regulator freeze-separates air. Why sink a bunch of energy into freezing stuff when you have incredibly cold temperatures right outside?

Chapter 20:

  • Lots of small wording and technical changes about Pathfinder

Chapter 21

  • More info added about Mark's trip

The saddlebags I made for the Pathfinder trip will come in handy for food storage. I can’t just store potatoes in the rover or trailer. They’d rot in the warm, pressurized environment. I’ll keep some in the rover for easy access, but the rest will be outside in the giant freezer that is this planet. The trailer will be packed pretty tight. It’ll have two bulky Hab batteries, the atmospheric regulator, the oxygenator, and my homemade heat reservoir

  • Extra info about what Mark's eating.

I’ve discovered that raw potatoes are disgusting. When I’m in the Hab, I cook my taters using a small microwave. I don’t have anything like that in the rover. I could easily bring the Hab’s microwave into the rover and wire it in, but the energy required to cook ten potatoes a day would actually cut into my driving distance.


Over the last few days, I cooked all the potatoes with the Hab’s microwave. It took quite a while, because the microwave can only hold four at a time. After cooking, I put them back out on the surface to freeze. Once frozen, I put them back in the rover’s saddlebags. This may seem like a waste of time, but it’s critical. Instead of eating raw potatoes during my trip, I’ll be eating (cold) precooked potatoes. First off, they’ll taste a lot better. But more important, they’ll be cooked. When you cook food, the proteins break down, and the food becomes easier to digest. I’ll get more calories out of it, and I need every calorie I can get my hands on.

  • More info about Mark's lack of navigation skills

But who knows? I can see it now: me holding a map, scratching my head, trying to figure out how I ended up on Venus.

Chapter 23:

  • Completely reworded section about the power meter. The following section added.

I needed a way to log the time of day and the wattage of each solar cell. One of the cells would be with me, but the other two would be dropped off and left far away. And the solution was the extra EVA suit I brought along. EVA suits have cameras recording everything they see. There’s one on the right arm (or the left if the astronaut is left-handed) and another above the faceplate. A time stamp is burned into the lower left corner of the image, just like on the shaky home videos Dad used to take.
My electronics kit has several power meters. So I figured, why make my own logging system? I can just film the power meter all day long. So that’s what I set up.

  • The preceding section removed

I made the bedroom in to a lab. I stacked my supply containers to form a rudimentary table, and used a sample box as a stool.
I needed a way to track the time of day and the wattage of the solar cell. The tricky part is logging it. And the solution is the extra EVA suit I brought along.
The cool thing about EVA suits is they have cameras recording everything they see. There's a camera on the right arm (or the left if the astronaut is left handed), and one above the faceplate. A time-stamp is burned in to the lower left corner of the image, just like the shaky home videos Dad used to take.
My electronics kit has several power meters. So I figure: why make my own logging system?

  • Added info about Mark's state of mind after accidentally breaking Pathfinder.

Damn it’s tempting. If I could get Opportunity’s radio working, I’d be in touch with humanity again. NASA would continually tell me my exact position and best course, warn me if another storm was on its way, and generally be there watching over me.

But if I’m being honest, that’s not the real reason I’m interested. I’m sick of being on my own, damn it! Once I got Pathfinder working, I got used to talking to Earth. All that went away because I leaned a drill against the wrong table, and now I’m alone again. I could end that in just four sols.
But it’s an irrational, stupid thought. I’m only eleven sols away from the MAV.

Chapter 25:

  • Info added about Venkat's office.

BRUCE TRUDGED into Venkat’s office and unceremoniously plopped down in a chair. He dropped his briefcase and let his arms hang limp.
“Have a good flight?” Venkat asked.
“I only have a passing memory of what sleep is,” Bruce said.

  • Changed wording from "If I survive this I’ll tell people I pissed my way in to orbit." to "If I survive this I’ll tell people I was pissing rocket fuel."

  • More info about Mark's state of mind before launching back into orbit.

I still can’t quite believe that this is really it. I’m really leaving. This frigid desert has been my home for a year and a half. I figured out how to survive, at least for a while, and I got used to how things worked. My terrifying struggle to stay alive became somehow routine. Get up in the morning, eat breakfast, tend my crops, fix broken stuff, eat lunch, answer e-mail, watch TV, eat dinner, go to bed. The life of a modern farmer.
Then I was a trucker, doing a long haul across the world. And finally, a construction worker, rebuilding a ship in ways no one ever considered before this. I’ve done a little of everything here, because I’m the only one around to do it.
That’s all over now. I have no more jobs to do, and no more nature to defeat.

  • Added a line about the mice in the room next to the airlock.

“Hey, Martinez,” said Beck over the radio. “Can you move my lab mice somewhere safe? They’re in the bio lab. It’s just one cage.”
“Copy, Beck,” said Martinez. “I’ll move them to the reactor room.”

  • Description of the MAV added

The MAV barely resembled a spacecraft as Beck had come to know them. The once sleek lines were now a jagged mess of missing hull segments and empty anchor points where noncritical components used to be.

Info added about Mark's parents.

The couple in Chicago clutched each other in sheer relief, then pulled the NASA representative in for a group hug.

info added about Mark's feelings toward NASA

I think about the sheer number of people who pulled together just to save my sorry ass, and I can barely comprehend it. My crewmates sacrificed a year of their lives to come back for me. Countless people at NASA worked day and night to invent rover and MAV modifications. All of JPL busted their asses to make a probe that was destroyed on launch. Then, instead of giving up, they made another probe to resupply Hermes. The China National Space Administration abandoned a project they’d worked on for years just to provide a booster.
The cost for my survival must have been hundreds of millions of dollars. All to save one dorky botanist. Why bother?
Well, okay. I know the answer to that. Part of it might be what I represent: progress, science, and the interplanetary future we’ve dreamed of for centuries. But really, they did it because every human being has a basic instinct to help each other out. It might not seem that way sometimes, but it’s true.

If a hiker gets lost in. My the mountains, people will coordinate a search. If a train crashes, people will line up to give blood. If an earthquake levels a city, people all over the world will send emergency supplies. This is so fundamentally human that it’s found in every culture without exception. Yes, there are assholes who just don’t care, but they’re massively outnumbered by the people who do. And because of that, I had billions of people on my side.

Pretty cool, eh?

The following passage was omitted entirely in the 2nd edition.

Watney finished his two slices of pizza and a coke. He had another half-hour to kill before going back to Johnson Space Center. Leaving the pizzeria, he sat on a public bench just outside.
Next week would be busy. He would be meeting the Ares-6 Engineer.
He had read her file, but had never met her in person. He wouldn't get much time to relax after that. The following six weeks would be filled with constant training as he tried to impart as much knowledge as he could. But that was something to worry about later. Right now, he took a deep breath of the fresh air and watched the people go by.
“Hey, I know you!” Came a voice from behind.
A young boy had strayed from his mother. “You're Mark Watney!”
“Sweetie,” the boy's mom said, embarrassed. “Don't bother people like that.”
“It's ok,” Watney shrugged.
“You went to Mars!” The boy said, his eyes wide with awe.
“Sure did,” Watney said. “Almost didn't make it back.”
“I know!” Said the boy. “That was awesome!”
“Sweetie!” The mom scolded. “That's rude.”
“So Mr. Watney,” the boy said, “If you could go to Mars again, like, if there was another mission and they wanted you to go, would you go?”
Watney scowled at him. “You out of your fucking mind?”
“Ok time to go,” the mom said, quickly herding the boy away. They receded in to the crowded sidewalk.
Watney snorted in their direction. Then he closed his eyes and felt the sun on his face. It was a nice, boring afternoon.

  • 23
    So detailed. Did you run git diff? May 9 at 15:50
  • 38
    @SatelliteofSin - I have both versions in my Calibre library, so I converted them into Docx documents, then used the compare/review tool in Microsoft Word to identify changes. I've ignored about 3000 words of minor changes (mostly to terminology or where a sentence has been moved on the same page) and focused only on alterations where one or more line (or an important word) has been added or deleted.
    – Valorum
    May 9 at 16:06
  • 30
    @Valorum - Could you be a little more specific?... Only kidding, that was way more comprehensive than I could ever have hoped for, and in such a short time that I half suspected you might BE Andy Weir! Many, many thanks!
    – GordonD
    May 9 at 17:05
  • 5
    All in all, far less significant than the changes in The Hobbit when Tolkien back-corrected it to match his LOTR scenario. May 10 at 12:35
  • 12
    @CarlWitthoft - I'm dreading someone asking that question...
    – Valorum
    May 10 at 13:06

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