Frozen spaceman particles
Discussion
Silly question time; In sci-fi films when someone is exposed to no-atmosphere space, standard practice is to immediately freeze and shatter in a million bits and slowly float away. In reality,I know the bodily fluids would quickly boil in situ, but wouldn't the vacuum of space (super cold though it is), to some extent have a insulating effect due to its poor heat conductivity, so bodily heat would have to leak away more slowly through convection.
Edited by fausTVR on Saturday 9th June 12:35
TheHeretic said:
It is possible to survive for x amount of time. As a poster said, it is like the bends. The lack of pressure means the gasses in your body would expand. No idea how long that would take to kill you. No doubt experiments have been done in a vacuum at least.
IIRC atmospheric pressure is about 15psi so I suspect that if you were suddenly exposed to a vacuum then there would be lots of cavities in your body at that pressure relative to the outside and so you'd explode with a sort of thrrrruuup noise - though as we know nobody would in fact hear it. I may be wrong about the colourful explosion though. 
BIANCO said:
It looks like a bodily explosion is not on the agenda then, but I bet it would be an extremely uncomfortable exercise considering the amount of eyeball and sinus pain you can get when descending in a plane when you have a cold.
RegMolehusband said:
Thanks Eric, that's interesting to know. Why would they reduce the pressure so much? To reduce leakage? 
To reduce weight.Air at the surface of the earth is 28% oxygen and 72% nitogen and some other gases. Obviously, we only need the oxygen part to live.
When early American sopacecraft were being designed, keeping weight down was crucial due to the rather weedy rockets they were using (especially the Redstone). Therefore the designers of the Mercury capsule decided that it would save a lot of weight if they went for a single gas atmosphere rather than a true air mixture as it would eliminate the need for nitrogen tanks, regulators, valves and all the associated plumbing.
Even though the second generation of spacecraft (Gemini and Apollo) were going to use much more powerful rockets, for simplicity it was decided to stick with what they knew i.e. oxygen only atmospheres.
Oxygen at 4.8 psi is fairly benign. One inherent danger in the 100% oxygen atmosphere is that the speccraft was pressurised at 14% psi when it was sitting on the pad but during launch the cabin pressure reduced to 4 psi for the remainder of the mission. But oxygen at sea level presure (14%) is highly explosive and of course they discovered the dangers of this with the Apollo 1 fire in 1967.
The first American spacecraft to use an air mix rather than pure oxygen was the space shuttle. I am sure tha all the new manned craft being developed at the moment will use an air mixture too.
The Russians have ALWAYS used an air mix - right from the very first Vostok.
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