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In Total Recall, Arnolds character is exposed to the Martian atmosphere without a spacesuit and recovers. It seems unlikely that anyone could survive, not even Arnold. How long could an unprotected human be exposed to the Martian atmosphere and still live? If it is possible that a person could survive, how would the exposure affect them physicaly?

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    I just would like to point out a similar scene in Watchmen, when Dr Manhattan teleports Laurie to Mars but then absent-mindedly forgets that she needs to breathe at first. – Mark Beadles Feb 16 '12 at 4:13
  • geoffreylandis.com/vacuum.html has some good info in the section Has Anybody Ever Survived Vacuum Exposure in Real Life? – Tyson of the Northwest Feb 16 '12 at 23:45
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Mars has a maximum of .011 of Earth's atmospheric pressure at its the bottom of its deepest depth. But the Armstrong limit, the pressure where water boils at the normal temperature of the human body, is only 0.0618 atmosphere. It is possible that the blood itself would not boil immediately: but all saliva, tears, skin moisture and most importantly the water in the alveoli of the lungs would boil away, which would cause death within a few minutes.

Also, the oxygen fraction is only 0.13% so there is nothing useful to breathe even if you could manage to. So while you were dying of evaporation you would die of suffocation.

Finally, the average annual temperature is −63 °C/−82 °F. Honestly though, this is survivable unprotected for longer than the atmosphere is and won't kill you that quickly.

However - yes, a human probably could survive for 1 or 2 minutes, tops, if they had the presence of mind to hold their breath and close their mouth and eyes and not panic. [EDIT: Holding your breath is not a good idea during decompression, it seems]. But they'd be in very bad shape.

  • Thanks @Aric TenEyck for pointing out the breath-holding problem, which would apply if you suddenly decompress from Earth atmosphere to Mars atmosphere. – Mark Beadles Feb 16 '12 at 4:06
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    there are some periods (dependent on the mars season) where the temperature is tolerable – this wouldn’t protect you from the vacuum, but ensure that you have your ~10 seconds of useful consciousness in vacuum. – flying sheep Aug 7 '12 at 10:48
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    The UV is irrelevant. You wouldn't be alive long enough for radiation to have any meaningful effect. – Donald.McLean Nov 5 '12 at 20:41
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    Of course, a lot depends on the physical fitness of the individual. A fit, healthy, athletic person would be much more likely to survive than, well, me. – JohnL Nov 5 '12 at 20:47
  • @Donald.McLean That was most assuredly not in the original answer and, you're right, makes no sense. – Mark Beadles Nov 5 '12 at 21:58
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Mars is not a total vacuum, but at 1% of Earth's atmosphere, is close enough as far as human survival is concerned.

Geoffrey Landis has a good discussion of human vacuum exposure at his site.

Short answer: 10 seconds of "useful consciousness", another 10-20 seconds of pain before passing out, but as much as a minute beyond that before permanent damage happens.

Other than the eyes popping out, that scene was relatively plausible.

Also, despite what Mark Beadles says, you don't want to hold your breath. Trying to keep pressure in your lungs will destroy them.

  • Having your lungs open to the vacuum will also destroy them because your alveoli will dehydrate. It's really a lose-lose situation. – Mark Beadles Feb 16 '12 at 3:58
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    Everything I've read says that holding your breath will destroy them slightly faster. But if you're at the point where it matters to you, you're pretty much screwed either way. :) – Aric TenEyck Feb 16 '12 at 4:00
  • I think the breath-holding has to do with the decompression phase, and not the vacuum itself. But it's hard to have one without the other, so good point. – Mark Beadles Feb 16 '12 at 4:02
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    @MarkBeadles I wouldn't say it's entirely a losing situation. After all, you are on Mars! – user1027 Feb 16 '12 at 4:10
  • Relatively plausible? Well, in that movie, yes, but as I remember he was was resisting explosive decompression by holding on to something and being pulled horizontal by the wind. Human beings can't do that. Chimps can't do that. The T-800 would have difficulty. – Beta Mar 27 '13 at 15:04
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For the face, it's as if you block your nose and close mouth and blow out with 1-4 kilos of force, i think it's just past the limit of outward pressure of what a human can seal in. for all i know it could be like a CO2 canister blowing up in your mouth!

You couldnt hold your breath on mars for very long. the pressure differential is about 1/100, 1m of water is about 1 atm, so it's like plunging to 100 meters too fast. the air in your lungs would try to expand to 100 times its normal pressure, saved only by your lips and nose. that's not humanly sustainable.

Also your ears and sinuses would pop, if they werent decompressed. they would have 100 times pressure! gas in belly would probably not be directly pressures as belly is a strong barrier. it depends how strong your bum is, but your belly would be sucked in every direction with 0.011 atmo's pressure, it's -100 kilos per square meter sucking force? so 100grams per square centimeter

would it be like putting vaccuum cleaners on your eyes? well it would be like a sink plunger with 1 pound weight hanging off each eye, 1-3kilos pulling out your lips and cheeks, and 25 or 50 kilos sucking your ribcage and neck at 360 degrees.

you'd struggle to hold the air in! you should bandage all your head up and maybe you would get just bad eye and ear strain for a few seconds? you would have to block your nose against 200grams of sucking force also.

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I would think that ideally you would want to exhale a good amount of air, but retain enough in your lungs to create the most positive pressure you could safely hold. Like the pressure when you take the deepest breath and then hold it. I would also think closing your eyes tightly and pinching your nose too, for maximum longevity!

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