For someone floating in space without a space suit, but with some sort of mask or airtight helmet providing air, how long would it take for that person to die?
A person without water will die after about three days.
So long as the air was pressurized, he could breathe fine, but would either burn up in direct sunlight, or if in shade (or far away enough from the sun) would radiate away his body heat into the vacuum, until he froze to death, which in both cases would happen fairly quickly.
I wonder where the “goldielocks” zone is for a human body in space, though.
I’m pretty sure the water would evaporate from a body in space before that. I’d imagine if one survived for over an hour (which I doubt) his skin would be as dry as sand.
That person better start spinning relative to the Sun. Even under the best circumstances, half the body will be in sunlight and half will be in the shade, and the shady side approaches absolute zero.
I think it’s likely the person could be dead in minutes, even seconds. How far away from the Sun? If the person is orbiting the Earth, I would bet on not surviving through the half-orbit while the Earth eclipses the sun.
I think Explosive decompression is the bigger concern. can you live with all the vessels and veins in your skin rupturered, your eyeballs boiling, and your nose gushing blood like a faucet?
If the breathing apparatus tries to pump air into the lungs at 1 atmosphere, the lungs would rupture. If you use a pressure low enough not to damage the lungs, it may not be enough oxygen to keep a person alive.
That’s a movie myth
He would neither burn up nor freeze.
0.2 atmosphere of pure O[sub]2[/sub] is more than enough - that’s how much oxygen you get at sea level - and it is just barely possible to survive at a third of that, which is what you get at the summit of Mount Everest with no breathing apparatus. So 0.07 atmosphere or 1.7 psi. That won’t burst you.
If you had an adequate breathing apparatus, but otherwise no real protection, I believe the first thing you would succumb to is either intense heat from direct sunlight, or freezing as you’re essentially a blackbody radiating away your body heat (or taking in too much, too fast – plus radiation) as there is nothing to act as an insulator, like a suit or an atmosphere.
There’s also nothing to carry away the heat. Freezing would be out of the question, I think.
Wait, so he’s got a pressurised helmet on his head, with some sort of cuff to seal it to his neck, but apart from that, he’s wearing T shirt and jeans or something?
That’s going to be a problem, because the opening to his respiratory system is pressurised, but his ribcage, abdomen and diaphragm are not. He won’t be able to exhale. (which is what scr4 was talking about in post #7). The effect will be similar if you do the same experiment on Earth and pressurise the helmet above ambient.
There has been talk of using building lightweight suits that use elastic pressure on the body rather than gas pressure. Has he got one of those, or is he just dressed casually?
Heat certainly can radiate without a medium to carry it. It might not be immediate, and something else might kill you sooner, but ultimately freezing would kill you.
Yes there is. Water vapor from the body.
The breathing apparatus could be designed to handle it, by alternately pumping oxygen into the lungs and pumping it out.
First, the seal around the neck is a problem.
Second, the water in your skin will boil; you may not have explosive decompression, but your outer layer of skin would start to dry out until it was leather, or rather long pork jerky, say down to about 1/4 inch or 1/2 inch? You would become dehydated in short order. Fortunately, then, your skin would be dead before you suffered any sunburn. You’d need the sun to stay warm. Maybe trying to move would crack the skin open and you’d quickly gush blood and die of blood loss/dehydration. Maybe places like the neck arteries outside the ring seal, the leg arteries - are too close to the surface, and during the dry-out process you’d create blood clots that would travel to the heart or lungs and kill you; certainly freeze-drying the arteries and veins in the legs and arms where they are close to the surface would mean loss of the limbs within a minute… Loss of circulation to the head would be the kindest, quickest way to go. Maybe during the drying-out process the blood vessels crack and you get large blood blisters at certain points…
Oddly, nobody has done any relevant experiments yet. My uneducated guess is that the drying-out process would reach its maximum in 2 to 5 minutes. If part of that process causes death by cutting off blood to the brain or loss of blood pressure, that would be the kindest part of the process. Otherwise it would be about 5 to 10 minutes of agony until the breathing process stopped from shock or other side effects, or the heart stopped.
If your body is pressurized, even to just a few psi, are you going to need a plug or two at the the other end to keep last nights mexican meal and tequila from coming out? (And maybe even some body parts after that!?)
The seal around the neck might be a problem too. To seal its going to have to press on the skin a fair bit, impeding critical blood flow to and from the head. I get a bit lightheaded just wearing a too snug a tie or turtle neck sweater. Throw in just enough pressure to have just enough O2 to keep you concious and its probably worse.
I think that it would be very hard to breathe if there is no air pressure on your chest. When you breathe on earth your don’t create a very large pressure difference between your lungs and the outside air. I also think you will have similar pressure problems with blood flow.
A Nova now episode about making less restrictive space suits discusses the absence of airpressure and the problems it causes for breathing and blood flow.
Let’s say he’s wearing the costume of an Edwardian cricketer. And a frock coat.
