The Martian

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.

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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.

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.

Grumpy Scot

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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.

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: 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.


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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.

Doc Premium member

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.


Factual error: When we return to Watney waking up in the sand after the storm, the sands have various patterns and hollows in them which would have been erased by a storm that caused as much trouble as this one.

Factual error: Teddy tells Purnell that he is the "director" of NASA. The chief of NASA is referred to as the administrator, not director.

Factual error: Earth's moon is in the frame as a clear crescent after the explosion when Mark goes out. Mars' moons are not spherical, so can't appear like that. (01:10:00 - 01:11:00)

Factual error: When the airlock blows off the "garden" section of the Hab, the initial leaks shows gases flowing to the inside of the chamber. The building pressure should be flowing to the outside as the airlock pressurizes.


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.

More mistakes in The Martian

Mark Watney: I admit it's fatally dangerous, but I'd get to fly around like Iron Man.

More quotes from The Martian

Trivia: The secret project created to use the Hermes to return to Mars to rescue Watney was called Project Elrond, a reference from the Lord of the Rings (also used in the original book of The Martian). Mitch Henderson, played by Sean Bean, was an attendee at the Project Elrond meeting. Sean Bean also played Boromir, who was an attendee at the Council of Elrond in the LOTR movie.


More trivia for The Martian

Answer: In the book, he's stranded on sol 6, and leaves on sol 549, making it 543 sols (554 days). In the movie, he's stranded on Sol 18 and leaves on sol 561, making it 542 sols.

More questions & answers from The Martian

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