Just curious. How long could you hang on in outer space in one of these suits?
I’m pretty sure you would die almost instantly in this rig.
The suit will inflate - if it manages to do this and stay sealed, and can hold, say, 7 psi of pressure without bursting (all of which seems unlikely), survival is possible, but the next problem is the air - the pressure at the mouthpiece may be high enough to cause injury.
If the supply pressure is lowered, there may not be enough oxygen to support survival - it’s not just the proportion of oxygen that matters - it’s the partial pressure of the oxygen.
In short, this rig seems unlikely to help very much at all.
Not instantly; it’s generally believed (since there haven’t been many volunteers for the experiment) that an unprotected human can survive a short time.
If he were in a completely airtight shit and has an air supply, it wouldn’t be any different from any other spacesuit. Since it’s soft and bulky, it will balloon out in vacuum, but he could probably survive as long as the air held out.
If it were just water tight, then the air will leak out faster, cutting into his survival time.
<resists the urge to joke about the typo>
How much of a concern would temperature regulation be? Would a drysuit prevent you from boiling in the sun and freezing in the shade?
As a matter of fact: No.
“Since it’s soft and bulky, it will balloon out in vacuum”
Combined with the typo, that’s a pretty horrid visual.
I own and dive a neoprene dry suit, great for water but I don’t fancy jumping into space in it. In that photo, he’s not totally covered, you can see his hair above his mask. Might make a difference to his survival in space? Their are also several valves on a dry suit, on of which will (on most) auto dump pressurised air after a certain point so it won’t hold much pressure. (I’m not great on space physics)
As Mangetout says, if, hypothetically, the drysuit could hold some small pressure, you might stand a chance.
Your main problem is an ability to breath, and an ability to breath something with a high enough partial pressure of oxygen to stay alive. You need to be able to breath without the pressure of the air exploding your lungs or simply overcoming your ability to exhale.
So, we fill the tanks with pure oxygen, to get the partial pressure up as high as we can. To stay alive you don’t need as much oxygen as you get in normal air, so we can pull the partial pressure back. The summit of Mt Everest has an air pressure 1/3[sup]rd[/sup] that of sea level. So people can clearly survive and operate for a limited time with one third the sea level partial pressure of oxygen. That means if you can manage breathing oxygen coming into your lungs at 1/3 * 1/5 * sea level pressure, you might hold on. That is just under 1 psi. That isn’t unbelievable.
A quick Google suggests that humans can manage roughly between 1 and 1.5 psi expiration pressure into a spirometer. So you could, in principle, manage to hold the the oxygen at 1psi without damage, but it would be at significant effort. You would not be able to do this for very long. So we need to get you 1 psi of pressure on your body to allow you to breath normally.
The limiting factor for the drysuit will be the seals. The main one that will be the limit will be the neck seal. If the neck seal will hold 1psi and you inflate the suit to that pressure, you will probably be able to safely breath 1psi oxygen, and you would probably survive for a while.
When it was new my old drysuit had a pretty good neck seal, and I would easily imagine it would hold 1psi. Indeed once the suit was on I had to manually pull open the neck seal to allow excess included air to be easily ejected. Over time the seals die.
Need answer fast?
In regards to a dry suit, no, it would not work very well or long in a vacuum. As others said it would instantly balloon-out and leak. NASA is actually experimenting with very, very skin-tight fitting future spacesuits. The idea is to contain your body tissue’s internal sea level pressure with a physical material alone, without the need to surround it with pressurized air.
As for a scuba regulator, they match the water’s external pressure on them to balance the amount of air pressure it takes to inflate your chest (lungs) against the water pressure at a given depth. The more water pressure against their external diaphragm the higher breathing pressure they deliver. Not sure what one would do in a vacuum, probably free-flow at a low pressure (which would be useful in space) but it would be unpredictable. Plus without a full-face mask/regulator I doubt your lips could make even a modest, survivable airtight seal for very long.
Reminds me of a great line from Futurama, when the ship is dragged underwater and the professor is asked how many atmospheres it can withstand he says:
"Well, it’s a spaceship, so anywhere between zero and one!"
Well, one guy did technically volunteer, but I don’t think that’s quite what he had in mind. Back in the 1960s, a guy named Jim LeBlanc was testing a space suit design in a specially built NASA vacuum chamber when basically the air hose came loose and he very quickly lost pressure in his suit. He passed out in about 15 seconds or so.
[QUOTE=Jim LeBlanc]
As I stumbled backwards, I could feel the saliva on my tongue starting to bubble, just before I went unconscious. And that’s kinda the last thing I remember.
[/QUOTE]
They got the door open in less than a minute and he regained consciousness even before a doctor could get in and examine him. He complained about his ears aching from the loss of pressure and repressurization, but otherwise suffered no ill effects from his ordeal.
The problem with a standard dry suit would be that it’s not designed for those pressures. If you ever saw The Abyss, you saw fictionalized versions of real-life hardsuits that are usually used under the kind of conditions necessary for really deep diving.
Two issues you’re going to run into are that the seals aren’t designed for non-pressure conditions, and ballooning. Earlier commenters incorrectly stated that drysuits aren’t designed for those kinds of pressures. Ten meters of water equals 1 atmosphere, and you must breathe air at the same pressure as the water around you, or your chest would be unable to expand (this is what your regulator does), and you wouldn’t be able to maintain the water-tightness of the suit. Drysuits would be utterly useless if they weren’t designed for multiple atmospheres of pressure. But, the seals aren’t designed for one-way pressure, so they probably would leak.
Ballooning is a bigger problem. You’re not going to be able to move. Space suits have non-expanding hard joints to prevent immobility. Diving drysuits don’t have to deal with greatly unequal pressure, so they don’t.
This is a modern version of a space activity suit, which uses mechanical pressure instead of air pressure.
The direction of the pressure inequality is going to be the biggie, I think - to the extent that diving apparatus is designed to cope with pressure, it’s largely about external pressure (perhaps balanced against an internal equalising pressure).
The scenario in this thread has all the pressure on the inside - the thing is probably quite likely to inflate and give at a seam.
Dry suits are tested for leaks by turning them inside out and inflating them with air, but not even to 1psi.
The boiling point of water (and blood) is the killer issue - literally. Unless the suit could hold 1-1.5 psi (earth’s atmosphere @ ~70K feet) across every bit of body surface, the boiling point would cross below body temperature. Your blood would literally boil and you’d pop instantly. U2 pilots are instructed to worry about leaks in their pressure suit because of this.
Deleted: engineer_comp_geek already relayed the story. Short answer: you don’t “pop” in a vacuum.
Something I didn’t think about earlier: you don’t need 1 atm. of pressure, just enough to prevent some pressure-related problems. Airplanes aren’t pressurized at 1 atm., for example, but keep an “altitude” that’s comfortable for most people, roughly 2,000 m (8,000 ft.) on most planes.
You can push that boundary significantly in this scenario since you’re wearing a breathing apparatus, on which the gas mixture can presumably be adjusted. If you’re using plain air, your limits are much lower, but if you adjust the oxygen mixture up, the suit itself just needs enough partial pressure to keep your tissues from offgassing. That happens at comparatively high altitudes/low pressures. Since you’re just trying to 1) keep alive and optionally 2) operate somewhat effectively, you can push the suit pressure down to as low as 2–3 psia, according to the info in this table about pressures at different elevations, but you probably couldn’t function for long at that low of a pressure. 8–10 psia would be good for long-term survival and activity.
If you’re postulating plain old air, then you’re pretty screwed at pressures any lower than 10 psia. Nitrogen offgassing is apparently a problem even in regular spacesuits, and they have a pre-EVA adjustment protocol, which includes switching to pure oxygen for 2 hours, and a short vigorous exercise period.
Indeed, that is pretty much the logic I used to get 1psi. The Armstrong Limit is a little under that, so 1psi seems a defensible base figure. There isn’t a lot of margin, but you would probably survive for a useful amount of time. 1psi vapour pressure of water occurs at 39 degrees, so it really is tight. Actual spacesuits are run at 4.7psi and pure oxygen. The additional 1.7 psi above the basic 3psi needed to keep the O[sub]2[/sub] partial pressure is needed to maintain hydration. 1psi will result in dehydration and probable short to medium term lung problems as a result.
I somehow doubt anyone is contemplating taking a dry suit and scuba gear to the ISS, but the question is interesting.