Surviving in Space Without a Spacesuit
Geoffrey writes "The recent movie Sunshine features a scene (echoing the famous scene in 2001: a Space Odyssey) in which two astronauts have to cross from one ship to another without spacesuits. But, can you survive in space without a spacesuit?
Morgan Smith, writing in Slate, asks whether this is realistic, and concludes: "Yes, for a very short time.""
A long time ago I took a pressure chamber ride at NASA to 27,000 ft. I lasted about 15 sec until uselessness (the crew master didn't let us go all the way to LOC), and 27,000 is not a particularly extreme altitude. Generally, 50,000 ft is considered the altitude at which the partial pressure of oxygen is no longer adequate to maintain consciousness. You can survive up to about 80,000 if you "pressure breathe", i.e have a rig that forces oxygen into your lungs at a lightly higher pressure than ambient, but not enough to bust your lungs.
And as TFA pointed out you will embolize if you hold your breath above that more or less 80,000 ft altitude.
So if the acronum YMMV ever applies, it's here.
Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
I've done 4 spacewalks and during vacuum chamber training we open our suit purge valve, allowing the pressure in the suit to drop a bit (from nominal 4.3 psi) and I did feel the sensation of the saliva bubbling; it is similar to the sensation of soda pop on your tongue. I haven't seen the movies mentioned (other than 2001), but my guess about vacuum exposure is that you are more likely to be injured by the flying debris (including your own velocity as you impact a wall or whatever) associated with sudden decompression through a hatch than by a very short exposure to 0 psi. During one chamber run, I had a water line poppet valve stick open when I disconnected from the chamber wall. The water stream broke up into droplets that immediately froze, producing an impressive shower of ice particles. Over about 5 to 10 seconds, the icing point traveled up the water stream and formed a clump around the poppet valve, sealing the leak. Oh, by the way, I tried whistling while EVA and even the nominal suit pressure is too low to produce an audible sound.