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Human in outer space without space suit

  1. Feb 11, 2008 #1
    I recently saw the movie 'Sunshine' where they send a mission to detonate a bomb and save the Sun from dying. In one of the scenes, two astronauts had to cover a distance in the outer space but they didn't have space suits available. They wrapped themselves in some kind of foil and the whole trip in outer space took them several seconds till they got in the space station.

    Is that physically possilbe? Can a human body survive a few seconds in outer space, just protected by a foil wrap?

    Another problem would be the pressure - the human body is designed to function under air pressure of 1 atmosphere. Wouldn't the blood vessels burst out in outer space due to the lack of such external pressure?
     
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  3. Feb 11, 2008 #2

    mgb_phys

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    Yes - you get frostbite/sunburn and a few broken blood vessels in your eyes and lungs.

    Ever sucked the air out of a bottle to get your lips to stick into it as a kid?
    Or had someone else expose a part of your skin to a vacuum as an older kid (see hickey).

    1 atmosphere is only 15PSI, your skin is quite strong - you probably don't want to hold your breath, lungs aren't that strong.
     
    Last edited: Feb 11, 2008
  4. Feb 11, 2008 #3
    Yes I remember one of the astronauts said to 'exhale slowly' during the flight in outer space. At the time I thought that was weird remark but aparently it was meant to protect the lungs from zero outer pressure.

    Has anyone ever flawn in outerspace without suit or these are just theoretical considerations?

    I calculated what would the thermall losses be without the foil, assuming skin surface of 2m^2, skin temperature of 300K, and Stephan-Boltzman law of a blackbody radiator. The austronaut would loose something like 1kJ/second. For 10 seconds, he would lose 10kJ. Such a nutritional energy is contained in less than a gram of carbohydrates.

    That makes me wonder was the foil-wrap really necessary to protect from loss of heat. Supposedly it will reflect part of the thermal radiation back, but on the other hand, at places where the foil is touching skin it actually increases the thermal conductivity to outer space.
     
    Last edited: Feb 11, 2008
  5. Feb 11, 2008 #4

    mgb_phys

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    Tricky, if you hold your breathe you are likely to rupture a long, they don't expand to twice their original size. But if you breath out you will quickly lose conciousness as the olxygen in your blood diffuses into vacuum.
    Best thing is probably to wrap your chest in duct tape and hold your breath!
     
  6. Feb 11, 2008 #5
    Another problem would be the 'decompression sickness' where the nitrogen dissolved in blood will start to form bubbles under the low pressure.
     
  7. Feb 11, 2008 #6

    mgb_phys

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    Probably not - with a vacuum in the lungs the pressure difference will extract all the dissolved gas from the blood very efficently so bubbles forming isn't a big problem.
    Remember you are only 1atm over-pressure.
     
  8. Feb 11, 2008 #7
    I found some article explaining all the effects: http://www.damninteresting.com/?p=741

     
  9. Feb 11, 2008 #8

    mgb_phys

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    Not sure why the article is convinced that the lungs will efficently remove O2 but allow N2 to form bubbles - the pressure in the blood isn't going to drop very much.
    Anyway there is current opinion in the diving medicine community (at least when I used to dive actively) that 'the bends' is more due to air leaking into the blood from micro tears in the lungs (micro air embulisms) than classical dissovled gas -> bubble model.

    Also a good summary here http://www.sff.net/people/geoffrey.landis/vacuum.html
    The original Nasa page seems to have gone in the great Nasa cull of anything useful on their public sites!
     
  10. Feb 11, 2008 #9
    Yes you can survive, especially if the vacuum exposure is planned. E.g, the Apollo spacecraft used a 5 psi pure O2 environment, as do all space suits today. This eliminates any concern over decompression sickness ("the bends").

    In a 2001 "open the pod bay doors, Hal" situation, the astronaut would dial down the pure O2 environment to around 1 psi before blowing the hatch. This greatly reduces the injury from barotrauma (sudden pressure decrease).

    In such a situation you might have 15 sec of useful consciousness.

    OTOH if the spacecraft has a 14.7 psi N2/O2 cabin and has sudden, unexpected pressure loss, the chances are very poor. The shock (barotramua) of sudden depressurization from 14.7 psi can stun and disorient.
     
  11. Feb 11, 2008 #10

    mgb_phys

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    Fortunately the screaming that accompanies an explosive decompression is an efficent method of depressurising the lungs!
     
  12. Feb 11, 2008 #11
    How rapid a decompression to 0 atm can the ear drums withstand before rupturing? Would the eustachian tubes be wide enough to allow instantaneous pressure equilibration?
     
  13. Feb 11, 2008 #12

    mgb_phys

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    If your mouth is open (see screaming above) and your tubes aren't blocked then it reaches equilibrium pretty quickly, there isn't much volume of air behind your ear drums to remove.
    They can also survive a 1bar pessure difference without rupturing (although it hurts!)
     
  14. Feb 11, 2008 #13
    Did they wrap shiny side out or matte side out?:rolleyes:
     
  15. Feb 11, 2008 #14
    It would be possible but I wouldn't advise it. I am sure if it had no effect on the human body, people wouldn't bother with the whole suit thing. What I don't get is its freezing yet you can get sunburn? Its quite hard to imagine being freezing and yet having the sun beating down on you?...
     
  16. Feb 11, 2008 #15

    mgb_phys

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    You don't freeze, although it is cold in space there is nothing to carry the heat away - it's like the ultimate thermos flask!

    Sunburn is a major problem. Remember sunburn isn't heat - it's UV light. There is a big sun up there and no atmosphere or ozone layer to protect you.
    On a sunny day on a mountain you can sun burn on unprotected skin in minutes - I've done it in Hawaii at 14,500ft , it wasn't cold so I only had a t shirt on. In space you can probably get severe burns in seconds.
     
    Last edited: Feb 11, 2008
  17. Feb 11, 2008 #16
    Oh yeah, an example would be like when you go skiing you can get sunburnt and it can be freezing. Thanks.
     
  18. Feb 12, 2008 #17
    Sunburn and freezing are a moot point for the discussed scenario: human vacuum survival.

    Under optimal conditions you'd have about 15 sec. of useful consciousness. After that you're dead, unless another suited individual dragged your unconscious body along.

    Also, the 15 sec isn't all exposed to solar radiation. You have to open the hatch of your ship, go through space, enter the hatch of the destination ship, then close the door and start repressurization.

    All of that subtracts from the approx. 15 sec. You'd be exposed to solar radiation for (at most) 5-10 sec. Also the scenario is without a pressure suit, not unclothed, which would give some UV protection.

    The total solar energy above the atmosphere is about 1350 watts/m^2, roughly 1.5% of this in the UV-B range, or 20 watts/m^2: http://exp-studies.tor.ec.gc.ca/e/ozone/uv_index_definition.htm

    That is roughly the UV-B radiation produced by some tanning beds (Woollons, Clingen, Price, Arlett, & Green, 1997).

    You basically have about 15 sec, and even that assumes a planned event, and probably a pure O2 cabin/suit environment. After that it doesn't matter how cold or sunburned you get, as you'd be dead.
     
  19. Feb 19, 2008 #18

    Garth

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  20. Feb 19, 2008 #19

    rbj

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    be sure to disconnect/power_down the mutinous killer computer when you get back inside. maybe he'll sing "Daisy" for you as his consciousness drifts into oblivion.
     
  21. Feb 19, 2008 #20
    i've read that 5 times and it makes no more sense than it did the first time :rofl:
     
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