What would happen if an astronaut took off suit in space?

  1. Sorry if this question seems like an elementary school topic but I don't really recall anyone really telling me what would happen is an astronaut took off some part of his space suit. I recall that for some reason his blood would boil (?), would he explode(literally) because of no pressure of would he immediately freeze because of low temperatures? TIA
  2. jcsd
  3. Ha ha, my profs loved to be so morbid. The blood will boil, due to vapor pressure properties of blood (mostly water?), and it is a type of referential based thought "process" that associates temperature with boiling. So, a liquid is liquid (as well as solid matter--think of ice sitting in the freezer that erodes over time, which is sublimation and dry ice does this better) at a particular ambient (surrounding) pressure, which in our experience is atmospheric pressure.
    Scuba divers also experience blood "boiling" in a sense too where the bends is gaseous nitrogen coming out of gaseous solution in human blood in the same way as a opened soda drink fizzes out carbon dioxide. To adjust this the air tank gas solution is modified with other gases for deep dives, which is helium and/or some other noble gas in place of the problematic nitrogen.

    EDIT: Re: Error on "the blood will boil" ,my misconception, Evo's link has info that the blood outgassing is not as dramatic by skin boundary containment.

    Last edited: Aug 8, 2006
  4. Evo

    Staff: Mentor

    Here is what happens.

    "How long can a human live unprotected in space?

    If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

    Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

    You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn. "

  5. DaveC426913

    DaveC426913 16,536
    Gold Member

    This is actually what kills divers more than the bends - holding their breath while ascending. The overpressure of the expanding air forces its way out by bursting the alveolar sacs and the air escapes into the pleural cavity. Basically, their lungs bleed to death. A mere 25% overpressure is enough to do this.

    It would surprise me if you didn't end up with great big bruises. Anyone who has ever gotten a "hickey" or sucked their face into a drinking glass knows how easy it is to get a large bruise from even a weak vacuum.
  6. Evo

    Staff: Mentor

    I'm wondering about the exposure to extreme heat and cold which I thought would be an issue.
  7. Another God

    Another God 985
    Staff Emeritus
    Gold Member

    I'm sorry Evo, but I have it on a very highly respected authoritative source that your answer is unfortunately wrong.

    "The Hitch Hiker's Guide to the Galaxy says that if you hold a
    lungful of air you can survive in the total vacuum of space for
    about thirty seconds."

    And we all know that "The Hitch Hiker's Guide to the Galaxy is a wholly remarkable
    book. It has been compiled and recompiled many times over many
    years and under many different editorships. It contains
    contributions from countless numbers of travellers and

    So i don't want to see anyone trying to disagree with this source! OK? :D

    So make sure you take a big breathful of air and hold on tight!
  8. Evo

    Staff: Mentor

    :rofl: okeedokee, we wouldn't want to go against the vast knowledege of The hitch hiker's guide", I mean what does NASA know? :biggrin:
  9. Another God

    Another God 985
    Staff Emeritus
    Gold Member

    Clearly nothing. Thats why they're still stuck on this harmless backwater planet!
  10. DaveC426913

    DaveC426913 16,536
    Gold Member

    Uh, mostly harmless, thankyouverymuch.
  11. Another God

    Another God 985
    Staff Emeritus
    Gold Member

    Oh, did you get the new edition? Is it worth the upgrade?
  12. DaveC426913

    DaveC426913 16,536
    Gold Member

    As you should know, the new edition was sent back in time, and thus came out before the original.
  13. Arthur C Clarke used that scenario in one of his short stories, for some reason passengers had to transfer to another space ship through adjacent but not connectable air lock doors (also in 2001 a space odyssey).
    I don’t know what references the esteemed si fi author used but he is known for his realistic approach to many such escape and rescue stories.
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