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Mark Watney, in the movie The Martian, says that,

If the HAB breaches, I'm just gonna, kind of... implode.

The corresponding novel, by Andy Weir, says he will explode (as pointed out by @MikaelSundberg).

I think he will neither explode, nor implode, but simply die of cold and asphyxiation.

Can anyone scientifically explain what will happen?

PS: The HAB is a NASA designed habitat for humans on Mars.

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  • $\begingroup$ The strange thing about this, is that in the book Mark actually says 'explode' not 'implode'. I wonder why it was changed in the movie. $\endgroup$ Dec 30, 2015 at 23:26
  • $\begingroup$ @MikaelSundberg as simplicis points out, due to the low air pressure, the air will be sucked out instantly, causing lungs to implode. His veins and skin will bulge, but the human body seems to be capable of handling the extra pressure. I think he will freeze before the pressure causes him to explode. I think the book had it wrong and they corrected it in the movie. $\endgroup$
    – xyz
    Dec 31, 2015 at 1:04
  • $\begingroup$ As mentioned below, this is at least "triple jeopardy". You will die by: 1) extremely low atmospheric pressure; 2) extremely high CO2 content of the atmosphere; 3) extremely low temperatures; 4) radiation exposure from an atmosphere that is too thin to stop the solar wind; 5) very little availability of water; 6) absolutely NO availability of food, anywhere on the planet, and earth plants cannot grow in Martian conditions. There's no doubt about it ... the Martian environment absolutely sucks. $\endgroup$ Feb 2, 2021 at 2:56

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The Martian atmosphere is effectively vacuum. He would be unconscious in less than 20 seconds and the he will end up freeze dried.

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The Martian atmospheric pressure is approximately equal to $0.6\%$ of Earth's mean, at sea level, mostly consisted of $CO_2$ ($98\%$).

This is equivalent of pressure at altitude of approximately $17 km$ in the Earth atmosphere, with boiling point $30 ^oC$.

The pilots use oxygen masks at altitudes $> 4km$, so even if Mars's atmosphere was entirely of $O_2$, people wouldn't survive.

Regarding the temperatures on Mars, they vary from $-150 ^oC$ to $+20 ^o C$.

Consequently, sure death by asphyxiation and depending on the location and season, instant or later freezing, which will be accelerated by the low boiling point, especially if there is no suit.

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  • $\begingroup$ The movie is scientifically correct, so can you please elaborate on the imploding part as well? I don't think they made an error $\endgroup$
    – xyz
    Dec 25, 2015 at 20:58
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    $\begingroup$ Yeah, that makes sense. I had though imploding due to air pressure only, which had me confused. Accepted your answer, Thanks! $\endgroup$
    – xyz
    Dec 25, 2015 at 22:29
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    $\begingroup$ The pressure of the atmosphere (or vacuum) doesn't matter to the biological effects. Human skin and tissue are very strong and they keep the internal pressure much higher than the atmospheric pressure under these conditions, i.e. the atmospheric boiling point simply doesn't matter. The essential effect is, as you said, near instant asphyxiation. $\endgroup$
    – CuriousOne
    Dec 25, 2015 at 23:48
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    $\begingroup$ You have to model the human body as a series of tissues that are encapsulating each other. There is the dermis, then a fatty layer, then connective tissue that holds the muscles together etc. Each of these layers can expand somewhat to allow for movement, but they are also holding the body together. If they didn't, we would be like jellyfish and basically rupture from our internal pressure. To prevent that the skin and connective tissue have to withstand significant pressure beyond the blood pressure. That will keep a body intact and the blood from boiling. $\endgroup$
    – CuriousOne
    Dec 31, 2015 at 3:57
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    $\begingroup$ Note: The Earth's pressure at ~17km is not 0.6%, it is closer to 10% of the pressure at sea level. You need to double the height to ~35km to reach 0.6% of the pressure of Mars. $\endgroup$
    – Harsha
    Feb 2, 2021 at 4:17
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It has appears in may movies and books, the clear point is that, in the BEST scenario you have 40 seconds to get back to normal atmosphere or you are dead. In this case, you see what is happening and you force all the air out of your body but not before oxygenating your blood though apnea rapid breathing just before been exposed.

worst case scenario, your decide to hold your breath, the 100 times of less pressure of the atmosphere, make the air of your lungs expand further till the tissue rupture, not sure if would be an explosion but if you have your ear in his chest you will hear the crack of ribs and diaphragm.

now back to the best case, 40 seconds... you are moving towards to airlock. The low atmosphere now is trying to pull out the air in your veins, your body swell, maybe your eyes too, (1990 total recall movie). I read somewhere that the skin is elastic but it is also strong, and will hold your body together, blood pressure will not drop enough for you to loose consciousness. In your veins, the atmospheric pressure has drop but not near Martian levels.

Second, supposing you are in a calm day at -60C with no wind. I think you dont freeze, I am almost sure you don't. just to be clear, in order to freeze water, it need to lose a lot of energy, and there is not enough air density to take away quickly that amount on energy.

If you fall to the ground which has much much more density than are and is already at -60C, that's something else. I think if your naked skin touches a -60C surfaces, will stick like a tinge sticks to a frozen pole.

so back to the point. Imagine that is your helmet that has been removed but your body still protected by the suit.. (at least you still keep your boots to be able to run without your skin touching the cold surface you will have this 40 sec maximum to walk or 20 if you run to reach safety without problems or consequences.

But I reiterate I dont think freezing will be a consequence of your exposure always you don't touch any surface with your naked skin. 1/100 the atmospheric pressure of earth I think would conduct temperature 100 times less than air.

However, 41 seconds later, once you die and fall to the cold powder iron oxide sand, I think your body quickly will freeze starting by the skin in contact and propagating the cold quickly from there to the rest of your body.

Note: Vacuum is a very very very good insulator and this is more close to vacuum than to earth conditions, so I dont think you will ever feel the cold, not in 40 seconds, not in 30 minutes. (again I am supposing that there is no wind)

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