The Martian inaccuracies (may contain spoilers).

[Brethern]

I don't like how the filming location doesn't look like Mars. I heard they filmed it it Jordan, but it seems like they could have found a more realistic (not to mention safer) place in Northern Africa.

The he spacesuit is a little weird too. The suit he wears on Mars doesn't appear pressurized at all for no apparent reason. It looks a little like he's wearing a cross between clone trooper armor and climbing gear.

The author of the book assumed that since they weren't trying to beat the soviets to the moon they'd have the time to produce a space suit that's more sensible to work in instead of the hey we're first suit of apollo.

[Tweeker]

Well, I did hate how they handled the hydrazine-gone-wrong part. I could easily suspend my disbelief for the situation and solution described in the book, but "I forgot to account for the oxygen I was exhaling" just made no damn sense.

That bothered me too..... I think what happened is they combined the 2 blow-ups from the book. If I recall he wore an oxygen mask, and the extra oxygen was from that.

[Cydonian Monk]

All of these "problems" with the movie just don't seem like problems to me. There's a huge difference between inaccuracy to make an otherwise unworkable plot function... and those done simply to give a better experience to the viewer....

From what I can tell every inaccuracy in the Martian movie - other than the sandstorm - falls into the latter category and is alright to be there.

This has been my take on nearly everything folks have grumbled about with the film. And there are certain issues that have been repeatedly raised that tell me immediately those mentioning them either weren't paying attention, didn't see the movie, or are being far too literal about it. (Not so much in this thread, mind you, just in general.)

Most of the issues I have with the film are also issues I had with the book. Oxygen poisoning in what's probably already a less than 1ATM environment (edit: and hey, maybe Mark was delusional when he said that).... The first sandstorm.... A few other minor quibbles. (I was actually kind of happy they let Mark have his Iron Man moment in the movie, as he seemed so delusionally disappointed he couldn't do it in the book. Not sure it made much of a difference.)

As for the setting, I think had they altered the landing site from Acidalia Planitia to neighboring Cydonia Labyrinthus I would've been 100% ok with their filming location. Not that I'm biased or anything......

Edited October 16, 2015 by Cydonian Monk

[Deutherius]

That bothered me too..... I think what happened is they combined the 2 blow-ups from the book. If I recall he wore an oxygen mask, and the extra oxygen was from that.

Essentially, yes.

There was only one explosion in the book, IIRC. Watney reduced a lot of hydrazine, noticed a large drop in expected water production, ran to Rover 2 for emergency shelter, because the HAB was like 60-70 % hydrogen that didn't burn in the chimney. Then he tricked the atmospheric regulator to drain all the oxygen to avoid unwanted explosion (only hydrogen and some nitrogen remaining), went in with an oxygen mask (for breathing) and a can of O2 (for burning). Didn't realize the mask was leaking O2 with every exhalation, and blew himself up.

Him exhaling oxygen would have no effect in the movie, as the atmosphere was normal at the time and he wore no gear (also stupid as hell... in the book he was way more cautious.)

[pTrevTrevs]

The author of the book assumed that since they weren't trying to beat the soviets to the moon they'd have the time to produce a space suit that's more sensible to work in instead of the hey we're first suit of apollo.

Yeah, but it's still a spacesuit. It still has to be pressurized, no matter what, and the fact that it's pressurized isn't something you can hide. It should look at least a little bloated, but t doesn't. I think they should have just had him use the suit he wore at the end for the whole movie.

Lots of the problems I have with the movie are just pet peeves, they don't make it a bad movie. In fact, I sort of want to go see it again.

[maltesh]

was mentioned in the film aswell but they cut the dialogues as if they would happen simultaneously. Like cheering in Mission Control right after Watney is secure again. But of course you want to keep it interesting for the viewers so it was okay I guess to do it like this.

I wasn't annoyed by the depicted simultaneity of that, as there wasn't actually any obvious direct communication between Mission Control and Mars in those scenes.

What did kind of irk me was the conversation between Kapoor and Watney, where Watney asks "What did the crew say when you told them?" and waits while Kapoor hesitates apparently for several dozen minutes, trying to figure out how to answer the question, long enough for Watney to follow up with an "Are you receiving me?"

Yes, it's his first human contact in months, and I guess Watney doesn't actually have anything to do other than sit in the rover and watch those 70's shows with some sort of countdown clock to let him know when he should be expecting a reply, it just felt a bit odd.

[GoSlash27]

The scene where he unbolts the airlock from the MAV, muscles it over the side, and just lets it tumble down the side of the stack *cringe*.

An Air Force Mechanic once dropped a socket down into a silo containing a Titan II (also hydrazine fueled). It didn't end well.

Still,

It's just a movie and it was very entertaining.

Best,

-Slashy

[Brethern]

Yeah, but it's still a spacesuit. It still has to be pressurized, no matter what, and the fact that it's pressurized isn't something you can hide. It should look at least a little bloated, but t doesn't. I think they should have just had him use the suit he wore at the end for the whole movie.

Lots of the problems I have with the movie are just pet peeves, they don't make it a bad movie. In fact, I sort of want to go see it again.

There's this thing called mechanical pressurized suits. The suit in the movie could be one very easily.

[Bill Phil]

I enjoyed it. It was also pretty accurate considering the average.

- - - Updated - - -

Well, I did hate how they handled the hydrazine-gone-wrong part. I could easily suspend my disbelief for the situation and solution described in the book, but "I forgot to account for the oxygen I was exhaling" just made no damn sense.

Well... You don't use all the oxygen you inhale.

[ndiver]

Oh no, the metal pellets are the catalyst that breaks hydrazine into H2 and N2. Hydrazine is the liquid he drops over it.

Thanks for the explanation. As the movie was not in my mother tongue, I might have missed this point.

[Deutherius]

Well... You don't use all the oxygen you inhale.

Of course, but I fail to see how that should make the scene any less stupid.

[Mad Rocket Scientist]

A couple:

Why design a lander which can blow over so easily in a sand storm?

The area around the pathfinder looks like this:

Rocky, not sandy.

They buried the RTG... But there are no cables from it to the hab?

- - - Updated - - -

Also, there was some talk of a "Oxygen reclaimer" or the like. That doesn't explain how there was enough oxygen in the hab to last for long enough.

[Superfluous J]

They buried the RTG... But there are no cables from it to the hab?

The RTG was not an in-use power source. They buried it to dispose of it. I'm not sure why they weren't using it for power, after bothering to carry it all the way to Mars, but I have extremely vague memories of it being mentioned in the book.

[Mad Rocket Scientist]

The RTG was not an in-use power source. They buried it to dispose of it. I'm not sure why they weren't using it for power, after bothering to carry it all the way to Mars, but I have extremely vague memories of it being mentioned in the book.

Ahhh, that makes more sense! I've still to read the book.

[maltesh]

The RTG was not an in-use power source. They buried it to dispose of it. I'm not sure why they weren't using it for power, after bothering to carry it all the way to Mars, but I have extremely vague memories of it being mentioned in the book.

It's used to power the ISRU gear for fueling the MAV, as I recall. By the time the crew arrives, the MAV is full of fuel, the humans can unpack and maintain the solar panels on the hab, so they tow the RTG off for disposal, so there's zero chance of accidentally breaking it open during a disaster.

[Alias72]

NASA apparently didn't want a metal cylinder filled with radioactive death near their astronauts. Also the damn thing only produced 100W. It was never really used for electricity in the Book, mostly just for Heat.

[Bill Phil]

Of course, but I fail to see how that should make the scene any less stupid.

Extra oxygen increases reaction rate for oxidation. Just not by much on this case. Sacrifices had to be made, it was changed to be less technical.

[Deutherius]

Extra oxygen increases reaction rate for oxidation. Just not by much on this case. Sacrifices had to be made, it was changed to be less technical.

Point is, he's not wearing any gear (relevant to oxygen, that is). Therefore, he's breathing the HAB's atmosphere, which has to already be oxygenated. He's exhaling even less oxygen than there is in the air around and unless he's breathing right into the chimney (he does the "woohoo-BLAM", but he's standing at least 1.5m away), there is just no way his breath could have affected the reaction to the extent depicted.

I get that sacrifices had to be made, but they could have come up with a different reason for the explosion ("too much hydrazine at once" - how hard was that?). They chose to go with the reason from the book instead, which made absolutely no sense in the context of the movie. Unless I missed something, of course.

On a different note, I don't remember any alarms in the movie, other than the "storm approaching", "low suit oxygen" and "Hermes depressurizing" ones. The HAB certainly seemed very quiet, as far as alarms go, especially during any fire. Did anyone catch any other alarms?

- - - Updated - - -

Also, while we are nitpicking - the awesome "space pirate" speech. The whole thing stands on the fact that "nobody can give Watney permission to board the MAV until he already does so" (which was true in the book).

Problem is, in the movie he carries the Pathfinder with him, has comm with Earth and even explains the space pirate thing to Houston (while demanding to be called Captain Blondbeard). (And this communication has to be go both ways, otherwise he could not be pondering on the "fastest man in the history of space exploration" before reaching the MAV)

Can't NASA just give him express permission to board and command the MAV, defeating his entire thought process? One sentence from Vincent, the freaking director of Ares missions, and Watney is not a space pirate anymore.

EDIT: Yes, I know I'm overthinking this stuff. For the record, I really liked the movie. But I liked the book way more.

Edited October 17, 2015 by Deutherius

[Bill Phil]

What percentage of oxygen in a mixture (air, specifically) makes hydrazine explode?

[Holo]

In the movie, you can see some people on Mars, but in real life, nobody has ever went to Mars.

[RuBisCO]

A manned landing system would most likely not by hydrazine but MMH and NTO bipropellant, not just for the higher ISP but for a much greater thrust to weight ratio possible, a pure hydrazine engine is limited in thrust by how much pressure and heat the catalytic reactor can handle, and the bigger the converter gets the less it can handle.

MMH+NTO combusts most instantly upon contact with each other, making a gagging mix of CO2,CO,H2O,N2,NH3,H2, I would not recommend trying to make water out of that directly. So taking in attitude control thruster that burns the stuff and collecting the exhaust would be highly noxious and dangerous. Maybe if the ratio is changed to be NTO high, but then their would be a lot of NOx, dirt bacteria loves that stuff, humans, not so much. Mark would need to wear his suit, burn a few kilograms over a day long period, then sleep in the rover for a few days while the atmospheric systems and soil bacteria deal with all the CO2,CO and NOx and then repeat.

[cicatrix]

One more inaccuracy besided those mentioned was the "live coverage" of the rescue. They explain how a signal takes 24 minutes to reach Mars in the Command Center but the rescue was without delay.

But this more an issue of making a film and the viewer stay involved than a plain wrong assumption like the other things you already mentioned.

Hermes and Mark talked to each other without any delay because they were close (Hermes was near Mars). What was heard on Earth came there with 24 minute delay. So Mark had been already rescued when it was still unknown on Earth.

- - - Updated - - -

An Air Force Mechanic once dropped a socket down into a silo containing a Titan II (also hydrazine fueled). It didn't end well.

*UDMH, probably (C₂H₈N₂), not hydrazine (N₂H₄). They're not the same thing, still they're both poisonous.

[BagelRabbit]

Alright, a great number of nitpicks from The Most Pedantic Man in the World! (Stay nitpick-ey, my friends.)

I'm going to say this right now: The spoilers are real in this post. Read on at your own risk.

~~~

First of all, the most inexcusable error was probably in this one scene where there the Earth was half-illuminated. On the 'dark side' of Earth, you could see stars. These were not city lights: they blended seamlessly with the stars on the other side of the Earth. Upon seeing this scene, I did a bit of a double-take, so I'm not entirely sure if what I saw was accurate. I'll bet my own $0.02USD that this mistake happened, though.

I can't say whether this was a mistake, but the pressure on Mars was consistently higher than it was supposed to be. This meant that the initial storm was possible, but also resulted in effects like the exhaust plume of the MAV looking rather conventional (big flame, much smoke) and not like it would in Mars's atmospheric conditions (hazy and spread-out). It also meant that the tarp that Watney used to cover the airlock could realistically blow inwards and outwards during storms. It wouldn't have done that on the "real" Mars.

Speaking of storms: The storm on Mars was producing "7,000-Newton forces," IIRC. The MAV had been rated for 500. However, over the remainder of the movie, there were several other storms that looked to be at least seven percent as powerful as the original one. Why in the world would NASA have made such a wimpy MAV if there seem to be powerful storms every several months or so? For that matter, how did the second MAV stay upright throughout this time? It's likely there were just as many storms that affected it.

And also speaking of storms: I don't know whether I'm correct here, but I'd wager that the particulates that seem to make up the storm are too large to create the electrostatic potential needed for lightning. It's a cool effect, though, so I won't be too hard on the guys.

And also speaking of storms: If I recall correctly, many of the little sample flags survived the storm's onslaught unharmed. Funny how the people are blown backwards, but the flags stay rock-steady. Hooray for NASA technology!

And also speaking of storms: Why was the HAB's lights flickering? You would think that temporary, repeated loss of power would be something that would be very concerning to the astronauts, but they don't even note that it's happening. The other dust storms didn't cause power loss, either. The light-flickering was probably for dramatic effect, but dramatic effect isn't science!

Acidalia Planitia in real life is very flat. There aren't big rocks all over the place. If there were, it would pose a serious problem to the NASA staff trying to land things in there. The terrain, however, is much less sandy. I think someone posted a picture of the Pathfinder landing site on a few pages back...

...oh, and while we're talking about Pathfinder, the thing was not connected to the parachute throughout landing. Rather, it bounced for a little while with the help of some nice-quality airbags. Therefore, Watney couldn't have used the parachute line to find the Sojourner rover. I will say, however, that the movie's depiction of the rover and the lander are pretty much spot-on.

While we're talking about the rover, I understand how cute it is, but why put it in the HAB and let it roam around randomly (at speeds far faster than it actually went, by the way)? Who's controlling it? Am I missing something here?

Speaking of something I probably am missing, why did they cut a hole out of the roof of the rover? There's probably a good reason for it, but the movie doesn't really explain what's going on there. [EDIT: It's apparently to get the oxygenator and the water reclaimer into the rover. I wish this was better explained in the movie though.] Also, if their only test that they performed (inflating a fancy NASA balloon) catastrophically failed in a way that would kill Watney, why did they eventually decide to go ahead with the plan anyway?

[The below section was added later, because I have slightly more time to talk about inaccuracies and I'm remembering more of them.]

As the Hermes approaches Earth (pre-course-changing-maneuver), it appears to be using its ion engines to accelerate towards the planet... even though the movie explicitly states that it's slowing down just minutes before.

The course seems to be changed without the ship actually maneuvering, by the way. It would have to turn 180 degrees if it was oriented correctly in the first place, which would have definitely been noted by NASA staff. Instead, they just state that the course is changing.

If Mark Watney broke his ribs, they should have hurt a lot more than they did in the movie, and roughly as much as they did in the book. No hugs for Watney after getting into the station! That would have hurt. A lot.

I'll probably remember more in a bit, too. Updates pending.

~~~

Anyways. I'll stop now. There's more that I could add, but I won't today. Maybe some other time...

-Upsilon

Edited October 18, 2015 by UpsilonAerospace
Pluralizing the word "months"

[Majorjim!]

S N I P

All good points. I have not read the book, only seen the flick.

The movie seemed to make a lot of assumptions that people will have already read the book.

This was a mistake. It felt rushed and it flat out failed to explain on more than one occasion what the hell was actually happening.

I hope for a decent directors cut. It could be four hours long and I would still be happy.

Edited October 18, 2015 by Majorjim

[maltesh]

Alright, a great number of nitpicks from The Most Pedantic Man in the World! (Stay nitpick-ey, my friends.)

Speaking of something I probably am missing, why did they cut a hole out of the roof of the rover? There's probably a good reason for it, but the movie doesn't really explain what's going on there. Also, if their only test that they performed (inflating a fancy NASA balloon) catastrophically failed in a way that would kill Watney, why did they eventually decide to go ahead with the plan anyway?

In the book, as I recall, he had to do it to get the oxygenator and the water reclaimer from the hab into the pressurized compartment of the first rover. Don't quite recall that being explained in the movie, but wasn't deliberately listening for it, either.