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: When the crew is walking around the area of the Hermes with artificial gravity created by spinning the ship, the angle of the crew members' bodies should be perpendicular to the curved floor of the ship. However, in multiple shots, the crew standing at different locations of the room are seen standing at the same angle, directly upright.
Other mistake: During the storm scene in the beginning of the movie, the astronauts' faces inside the helmets are brightly lit, meaning there's a light source pointed directly in their face. That's something that would render them mostly blind and unable to see and appears to be nothing but a dramatic effect for the camera. (00:05:00 - 00:08:00)
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.
Factual error: When Commander Lewis in the tethered MMU jet-pack-chair is catching Mark Watney flying Iron-Man style via air jets from the hole in his glove, Mark misses Lewis' hand and grabs the tether, with some angular velocity relative to Lewis. As Lewis pulls the tether hand-over-hand to bring Mark closer, the angular momentum should spin them faster and faster like ice skaters pulling their arms in or Argentinian bolas (weighted balls connected by a cord) winding faster and faster around a target. Only when solid contact is made would Lewis' MMU be able to counteract the spin. The expected rotational speed-up effect is not seen.
Other mistake: When devising the plan to retrieve Watney, it is mentioned that the Hermes crew have had to lash together all the webbing on board to make the longest possible tether. When this tether is used, there is no evidence of any lashing together or other extensions or modifications to lengthen it. The tether is one continuous length and is stored on a reel that was designed for the length of tether gathered on it.
Deliberate mistake: The atmosphere on Mars is only 1% as dense of that as Earth, so 175kph windstorms would feel like a light breeze. They would have very little effect on the astronauts or MAV. The writers of the book and the film were aware of this, it was a small cheat to let the rest of the story unfold.
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.
Character mistake: In a scene when Watney is recording his video log, he imagines what would happen if his pressurized shelter suddenly would break. He concludes that he would implode, but the correct wording would be explode.
Continuity mistake: When he signs his name on the white sheet, his last day at the hab, he signs 'Watney' and underlines the name with the tail of the 'y'. Next shot where he walks away from that sheet, it's just a scribble signature.
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.
Other mistake: The photo that is taken of Watney doing the Fonz pose is in vertical lines, much like the satellite imagery. However, the camera that took this photo was the pathfinder, which took normal black and white images, as seen in the "Yes" "No" question card scene.
Factual error: In the scene near the end where Mark is blasting off from Mars and before second stage engine cut-off, loose bolts are floating around the MAV cabin as if in zero G. With the engines still firing the acceleration would be pinning them to the deck. Even after SECO, it would take some time for the bolts (and probably a lot of Mars dust too) to jostle away from the floor and distribute evenly and randomly through the volume of the cabin.
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.
Continuity mistake: When Vincent Kapoor is talking about getting Congress to fund a sixth Aeries mission, he states Aeries 3 evacuated after 18 SOLs. Near the beginning of the movie, after Mark Watney regains consciousness and returns to the HAB, you see Rover 2 parked behind the HAB with the crew cab facing away from the HAB. Later when Mindy Parks is comparing the SOL 18 and SOL 54 pictures, Rover 2, in the SOL 18 picture, is turned 180° (with the crew cab facing toward the HAB) from what we saw when Mark returned to the HAB on SOL 18.
Continuity mistake: During the segment showing the rocket carrying supplies exploding, Teddy is shown in the background walking out of the control room. However in the next scene Teddy is standing with others in the control room.
Continuity mistake: When Bruce Ng is video calling Teddy Sanderson and Mitch Henderson to explain the modifications Watney will need to make to the Ares 4 MAV, there is a point in which the model MAV behind Bruce contains only a chair, all other chairs and the control console having been removed. Then, as Bruce and Mitch explain to Vincent that since Martinez will be remote-piloting the MAV, Watney doesn't need the controls, there is a shot of Bruce pulling several chairs and the control console out of the model.
Factual error: When Teddy is announcing Mark Watney's "death," the American flag is on the wrong side of the podium. This would be quite a goof for a government agency, especially one as image-conscious as NASA. Even in subsequent press conference scenes, the American flag is consistently to the left of the speaker, when it should be to the right.
Other mistake: When Vincent Kapoor first goes to JPL in Pasadena, he gets out of the car and the letters "JPL" are shown on the door. Since the shot is from the inside looking out at Kapoor, the letters should be backwards. No one labels a building for viewing from the inside. (00:43:00)
Continuity mistake: After discovering he is stranded and injured, Watney walks inside the hab and takes off his helmet and hood. His hairstyle changes three times between shots in a matter of seconds.
