Factual error: After Watney patches the blow out of one of the HAB's airlocks with plastic sheeting, tie down straps, and duct tape, he pressurizes the HAB and the plastic sheeting pushes out like an inflated balloon. Assuming the plastic and duct tape would hold this is correct, however the plastic would be much more taut given the pressure difference inside and outside.
Suggested correction: The plastic would certainly be flexing in and out because of the pressure of the wind gusts during the storm. We saw earlier that the gusts of the storms were strong enough to blow a suited explorer off their feet and push them across the surface. Let's say that the HAB is pressurized as much as it can be without blowing out of the plastic, tape, and bungees sealing the airlock. A storm gust would still be able to push the flexible plastic in momentarily, and it would pop back out after the gust passed.
The movie took liberties with the physics of Mars. The gusts on Mars wouldn't be able to blow over a person or a spaceship, let alone push them across the surface, but they needed it for the plot. But using the same physics they then have wedded themselves to, it could then be strong enough to cause the plastic to flap, even though in real life it wouldn't. This is more of a deliberate mistake than a factual error since the writers certainly knew what they did didn't match reality.
Except they didn't 'wed' themselves to their fictional physics. Towards the end of the film NASA tells Watney that a flimsy plastic covering on his ascent vehicle will not be dislodged on acceleration to Martian escape velocity because the atmosphere is too thin to cause any problems. That's cheating in anyone's books.
Factual error: Lewis replaces Beck on the EVA to rescue Watney. On a NASA mission, each crewman is a specialist in several areas. While all of the crew have trained on EVA, Beck is the specialist for Ares III meaning he practiced EVA protocol and maneuvers 2-3 times as much as any other crew member. So while it is a nice dramatic moment for Lewis to replace him, a real mission commander would trust the best trained personnel to do their jobs, as she is actually lowering the chances of success by replacing Beck.
Suggested correction: The Hermes missions are much more long term than any current NASA missions. In this fictional future, we have no evidence that Beck is the only one qualified enough to carry out this rescue. Additionally, Lewis has the emotional connection, having been the one to instruct them to leave Watney on Mars.
Other mistake: Rich Purnell explains his plan to redirect the Hermes to Mars in order to rescue Watney, positioning people to represent planets and using a stapler to show the trajectory of the vessel. He is talking to experienced, qualified engineers and technologists working at a very high level on the space programme. They don't need drama school play acting to be understand things like this. He could have explained his plan in the most complex and abstruse terms and they would have been way ahead of him.
Suggested correction: This isn't really a mistake. Yes, the character oversimplified the explanation but, as is shown when the character is introduced, he doesn't exhibit typical social behaviour. To him it's probably normal to explain things that way to strangers (which is basically what the people he's talking to are).
I think this is one of those borderline mistakes. Movies and TV shows often have a character over-simplify things, especially when involving science, for the audiences' sake and not for any of the characters. This type of mistake is similar to when characters start a conversation, but the show skips time by having characters arrive at a new location in the next scene without showing them traveling, but then the characters continue their conversation for the audiences' sake.
Factual error: Towards the end of the film Watney is told to discard the heavy nose cone of the Martian Ascent Vehicle and replace it with a flimsy plastic sheet because the atmosphere is so thin that it will not be damaged despite the vehicle being accelerated to Martian escape velocity - nearly 14,000 kmh. But the storm caused massive damage earlier. It cannot work both ways - if the atmosphere is so thin that it won't dislodge a jury rigged plastic canopy from an accelerating spacecraft, it cannot possibly whip up a storm like the one we see.
Suggested correction: Mars' atmosphere works very differently than Earth's. Near the surface, there are often heavy storms and winds. But go up near the edge of the atmosphere, it's drastically thinner. Earth's atmosphere doesn't differ THAT much; your logic would make sense for Earth. However, for Mars' atmosphere, the movie was accurate.
Absolute rubbish. It is a well established fact that the atmospheric pressure on Mars is 610 pascals, 1% of that on Earth. A 170 kmh wind storm on Mars (specified in the film) would be like a gentle, 18kmh breeze on earth. There is absolutely no way that a storm like the one we see at the beginning of the film could occur on Mars. The storm would barely scatter small pebbles about, let alone throw a spacesuited human body around. As for the atmosphere on Earth not differing form that on Mars... good grief, are you serious? Anyway, don't take my word for it. "No, it's not accurate!" Goddard cheerfully informed us (The Radio Times). "It's the one big buy of the movie, that because of the atmosphere, or lack thereof, Mars would never have a storm that big. But if we didn't do it, we wouldn't have a movie. It sort of kicks off the movie." You think Mr Goddard would be in a good position to comment. He wrote the screenplay.
You need to take the thickness of Mars' atmosphere into consideration.
Factual error: Prior to and during the orbital rendezvous rescue scene, the dialog states that a) the capsule with Watney is on a parabolic trajectory and will drop back to Mars b) the Hermes is on a swing-by trajectory that will carry it past mars c) the Hermes doesn't have the fuel to spare to do more than swing-by, i.e. They can't brake enough to even enter an orbit (yes, when one is on a fly-by, one has to brake to get into an orbit. Watney would be way slower still) d) the relative speed of the spaceships at the time of rendezvous is less than 20 m/s e) the spaceships are at a distance of less than 200m. All those statements can't be true at the same time. What orbit you are on is pretty much defined by your altitude and speed. If the speed and altitude of two spacecraft are the same, they are on the same (general shape of) orbit. Conversely, if they are on the same altitude but one is on a suborbital trajectory and one doing a swing-by, the latter is faster than the former by hundreds, if not thousands of m/s. By comparison, the rendezvous depicted in that scene would be like granny with her walker trying to "rendezvous" with an Amtrak train at full speed.The dialog states explicitly that the Hermes can't brake into orbit of Mars to pick up Watney because it doesn't have the necessary reaction mass to do that and get home too. If they can't even brake into orbit, they can brake to match Watney's speed even less. Even without that dialog, it wouldn't make sense either way. The acceleration required to do that would be measured in thousands of m/s. Translated into fuel, that would be dozens, if not hundreds of tons. No spacecraft this side of complete science fiction carries that much spare fuel, for the simple reason that lofting the extra weight to orbit would be prohibitively expensive.
Suggested correction: The dialogue doesn't state that Watney's capsule is on a parabolic trajectory. In fact, in one scene, Mitch and Bruce explain to Vincent that to allow the MAV to 'escape Mars' orbit', it needs to be made 5 tons lighter to allow it to reach the speed required for rendezvous.
Factual error: Teddy tells Purnell that he is the "director" of NASA. The chief of NASA is referred to as the administrator, not director.
Suggested correction: This could be a deliberate mistake. Is common in business for an "administrator" to be a clerical / entry level role (I've worked in such places). Referring to the character as Administrator of NASA could cause confusion in people not familiar with NASAs structure. By contrast, Director is likely to be understood by everyone as someone in charge, even if it's officially incorrect.
Plot hole: Rich Purnell started his calculations that required the Hermes to dock with the Tieyang Shen well before Teddy, the Director of NASA, found out about the confidential information about the Tieyang Shen even having enough fuel to be the booster.
Suggested correction: I don't think that is correct. When he first comes up with the idea to reroute the Hermes back to Mars he was thinking about/ working on the calculations for the original probe before it blew up.
Continuity mistake: Mark Watney is shown whittling the cross when he needs something to ignite to burn the hydrazine, the next shot the cross is intact. (00:26:18)
Suggested correction: It is possible Martinez brought more than one cross and the one Mark is holding while lying down isn't the one he was whittling just before.
Continuity mistake: Before planting the potatos he has to bring dirt into the HAB. The dirt on Mars is red due to high iron content. When we go to an inside view of the same dirt it's brown like here on earth.
Other mistake: When Matt Damon is brought back onto the Hermes, he is surrounded by his crewmates who are not in spacesuits. All air from the Hermes outside the control room had been expelled by the explosion, and could not have been replaced in the recovery time frame.
Suggested correction: The first priority would have been to only replenish the air in the corridors leading from the bridge to the airlock, since these are the 2 locations the crew need access to. They did not need to replace all the air in the ship at once, just a relatively small area.
