Because I wrote:
What's the problem?
t_3 responded:
you name it: "because there's no air!!"
That's no problem. A person in good shape can hold their breath for several minutes. That's plenty of time to close the outer hatch and pressurize the air lock.
if he just removes his sleeve -even only that- his suit would depressurize immediately, means he would die within a minute. btw, he also had the soil on the leg part.
The pressure difference is only 1 atmosphere. That's equivalent to laying at the bottom of a swimming pool.
so, if this was at all possible, since i guess the suit should be constructed in a way that would not allow it to have parts easily removed while in vacuum, any attempt to do so would probably cause explosive depressurization...
There's no such thing in space. You will only see it in movies.
...so that he would loose consciousness within seconds... while his crew member is also loosing consciousness already, because of a broken suit.
A person of ordinary fitness would be fine for several minutes, even if in the nude.
and because pressurization of a space travel airlock needs roughly 10 minutes - in the real world at least - there would be no way to make it in alive.
Well, if 10 minutes is true, then that indeed is a show stopper. Where did you get the idea that it would take 10 minutes to pressurize the Europa One air lock?
of course it is stretched for drama; but not in a completely deniable way imo. my concern would be more, that a little hydrazine on his suit would simply not cause that deadly problems, in first place...
There's that, too.
PS: The 2 major problems in space are overheating & radiation.
Contrary to folk wisdom, space is not cold and a person in the nude would not feel cold. Because space is a vacuum, there is heat transfer only by radiative loss. The heat transfer from blood to a person's skin in the shady side would more than make up for radiative loss (which is only a couple of percent of conductive and convective heat losses), so skin in the shade would not feel cold (or even very cool). However, the side in the sun will get hot in 10 or 20 minutes precisely because there is no heat loss. The problem would be less in the vacinity of Jupiter of course because the sun is so much weaker, but the major heat source is not the sun, it's the person's metabolism.
Over the length of hours, radiation dose would create real hazard. However, the current space walkers aren't really shielded from radiation today, and they typically spend several hours working outside the International Space Station. Even inside the ISS, there's not much in the way of shielding. We are shielded on Earth because of the magnetosphere and the ozone layer, but on Mars, for example, there's no shielding.
I think a reasonable way to overcome both overheating and radiation is to continuously go round a planet by crawler so that you're always in the dark. Since it rotates only once in 28 days, doing that on the moon would be pretty easy. I don't think Mars will ever be a home to us. I think living inside hollowed-out asteroids that are tied together and spinning around a common center of gravity is much more promising.
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I don't have a dog. And furthermore, my dog doesn't bite. And furthermore, you provoked him.
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t_3
9 years ago
very good point about the 1 atmo difference ;) hadn't thought about that.
regarding the conscious time span when being exposed to vacuum: there are lots of experiments, and even regular air force training, about hypoxia under high altitude conditions (30.000 ft). the usually show even trained humans will lose the ability to execute coordinated tasks within ~2 minutes - so, even under ideal conditions, you will have at very, very max 4-5 minutes to do whatever you have to. in addition removing a space suit (the like they did use) is a complex and -literally- exhausting task, that'll of course have an effect on how long you would be able to hold your breath.
the absolute minimum time for pressurization that i.e. can be achieved in the iss airlocks is around 15 mins, only in case of emergency; the standard procedure lasts for even 45mins. since the europa mission seems to use (almost) current technology, i'd expect their airlocks to be not by margins faster.
ps: here is a talk with andy weir and chris hadfield, where they, amongst others, gave some interesting details about iss space suits, and how they deal with radiation and heat:
https://www.youtube.com/watch?v=Wq3xtZ8AjPE
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markfilipak
9 years ago
I'm watching this, https://www.youtube.com/watch?v=Wq3xtZ8AjPE, right now. But I wanted to respond while I am thinking about something that came up in the video.
Spandex.
Instead of pressurized, Bib the Michelin Man-type space suits, I've seen it proposed that NASA simply use spandex elastic ... works for Superman.
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I don't have a dog. And furthermore, my dog doesn't bite. And furthermore, you provoked him.
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odieguard
8 years ago
I've read that you cannot hold your breath in a vacuum as long as you could underwater.
Here's an article about surviving a vacuum in regards to a scene from the movie Sunshine:
http://www.slate.com/articles/news_and_politics/explainer/2007/08/can_you_survive_in_space_without_a_spacesuit.html
To make it for even a few seconds, Sunshine's Mace must have expelled the air from his lungs before he ventured into the starry void. If he hadn't, the vacuum would have caused that oxygen to expand and rupture his lung tissue, forcing fatal air bubbles into his blood vessels, and ultimately his heart and brain.
They say 15 seconds and you're unconscious. However, he may still survive after falling unconscious (the article above suggested "a few minutes"), so I agree that the plan might have worked....depending upon how long it takes to remove the contaminated space suit from an unconscious person, and how long it takes to then cycle the airlock.
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shurbanm
8 years ago
That's no problem. A person in good shape can hold their breath for several minutes.
A person of ordinary fitness would be fine for several minutes, even if in the nude.
Maybe but not in vacuum. In vacuum conditions you won't be able to hold the air. Your lungs will expand like a balloon until they rupture (if indeed you are able to hold your breath which is questionable). The only way you can survive (for a bit longer) is if you expell all the air. That of course means you will only last for the time there is enough oxygen in your blood. Probably about 20-30 seconds max until you black out.
There's no such thing in space. You will only see it in movies.
Yes there is.
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markfilipak
8 years ago
Maybe but not in vacuum. In vacuum conditions you won't be able to hold the air. Your lungs will expand like a balloon until they rupture (if indeed you are able to hold your breath which is questionable). The only way you can survive (for a bit longer) is if you expell all the air. That of course means you will only last for the time there is enough oxygen in your blood. Probably about 20-30 seconds max until you black out.
Seems to me that you're making a common mistake. What you write about: not being able to hold one's breath, would be true for a person with a vacuum pump covering their mouth while the rest of their body is at one atmosphere. But in space, with vacuum everywhere, there would be no force to 'push' the air out of a person's lungs. Further, the small volume of air in the lungs would not exert enough force to cause a person to spontaneously blow it out or to rupture their lungs -- it is, after all, just one atmosphere of pressure difference at best, and it's that pressure difference that is at issue. It's a pressure difference that's equivalent to being 12 feet down in a swimming pool (but of course, in the 'other' direction: lower pressure, not higher pressure).
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
Sorry but you are wrong. You seem to be unclear about the physics involved.
The upshot - you lose consciousness in 15 seconds (which means you are essentially dead unless quickly aided by another)
https://www.scientificamerican.com/article/survival-in-space-unprotected-possible/
Vacuums are indeed lethal: Under extremely low pressure air trapped in the lungs expands, tearing the tender gas-exchange tissues. This is especially grave if you are holding your breath or inhaling deeply when the pressure drops. Water in the soft tissues of your body vaporizes, causing gross swelling, though the tight seal of your skin would prevent you from actually bursting apart. Your eyes, likewise, would refrain from exploding, but continued escape of gas and water vapor leads to rapid cooling of the mouth and airways.
Although the majority of knowledge on the effects of vacuum exposure comes from animal studies, there have also been several informative—and scary—depressurization accidents involving people. For example, in 1965 a technician inside a vacuum chamber at Johnson Space Center in Houston accidentally depressurized his space suit by disrupting a hose. After 12 to 15 seconds he lost consciousness. He regained it at 27 seconds, after his suit was repressurized to about half that of sea level. The man reported that his last memory before blacking out was of the moisture on his tongue beginning to boil as well as a loss of taste sensation that lingered for four days following the accident, but he was otherwise unharmed.
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markfilipak
8 years ago
Thank you for such a thoughtful post.
The information I have comes recently from NASA space physiologists. (By the way, I made a mistake in a previous post. I meant 12 meters depth per atmosphere, not 12 feet... my oops.)
Anna Gosline appears to be a pop-science writer of the type you regularly see on TV. She was writing in 2008 I wouldn't consider her any sort of authority.
I have not found any articles that site specific delta-atmosphere values associated with any of the various physical effects of decompression, but I did find that 5 atmospheres (~40 meters depth) is the rule of thumb for recreational diving. For less than 5 atmospheres of decompression, there are no marked effects and no special procedures are required.
The rib cage and chest muscles can certainly restrain the lungs for a pressure difference of 1 atmosphere.
I think the problem here is that it's seductive to believe that the pressure difference between ordinary conditions and a hard vacuum is a greater difference than 1 atmosphere; that dropping pressure must approach a hard vacuum along an exponential path such as:
1/2-vacuum = -1 atm. &
3/4-vacuum = -2 atm. &
7/8-vacuum = -4 atm. &
15/16-vacuum = -8 atm. &tc.
(or something similar). But that's not how it works. Atmospheres of pressure are not exponential. They are linear. Atmospheres don't approach zero asymptotically. A 'hard' vacuum is simply zero atm., not -infinitity atm. If your ribs, for example, can take +1 atm. (from 1 atm to 2), then they can take -1 atm. (from 1 to zero).
I'm sorry, but I don't believe that holding your breath in a vacuum will do any harm. People who claim that are extrapolating the experience of tank divers coming up from 5+ atm. and having to 'blow' as they ascend. Those people are in the tribe of people I address in the previous paragraph. One atmosphere is 1 atm. It is not any different from going from 2 atm. (12 meters down) to 1 atm. (surface).
Inside, we maintain about 1 atm. (in order to counter the 1 atm. of pressure in which we live). Sustained vacuum on soft tissues will cause problems -- just put a vacuum pump on your forearm -- but not in a few minutes, and not, I believe, when spread out over the entire body. Note: The counter articles I've found seem to deal with cases in which part of body was at 1 atm. while part was at zero (or very low) atm. and therefore don't really apply.
Now, real experiences are significant. The guy who's hand swelled up while at ...60-thousand feet (I believe)... is significant. But as I recall, the length of time was not mentioned -- once his hand swelled he wouldn't have been able to put his glove on and would have had to drop altitude to below 20-thousand feet (a task that, I'm sure, would have taken hours). Note: He was in a stratospheric ballon.
I think that the most serious effect of a 'hard' vacuum is that, even by pursing their lips, subjects will not be able to hold their breath. In other words, I don't think one's lip and cheek muscles can counter 1 atm.
From this point, I think if we disagree, we'll just have to agree to disagree. Farewell.
Edits: 'ribs' was 'bones' in p.6; added Notes to p.8 & 9.
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
I see and you are a science writer.
Once you get published on scientific american I guess maybe you could argue something. And what i posted was not her opinion but an actual case of somebody experiencing rapid decompression to vaccuum. The results are documented not by her.
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markfilipak
8 years ago
I see and you are a science writer.
No, I'm a scientist.
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
Aha right.... Well get published in scientific american and set her straight. Including maybe tell the guy who actually experienced this that he is wrong.
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markfilipak
8 years ago
...maybe tell the guy who actually experienced this that he is wrong.
To what do you refer?
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
the technician
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markfilipak
8 years ago
He undoubtedly lost consciousness because he fainted.
A single heart beat pumps ~70 mL. Thus, the amount of blood moved is 70 mL/beat. The body holds ~5L of blood. If the heart rate is 70 beats/min, then the length of time for blood to circulate is 1 minute (i.e., {5 L}/{70 mL/beat}/{70 beat/min}). If the heart rate is above 70 beat/min, then the time of circulation will be less, but that's offset somewhat by the fact that some of the returning blood will still be oxygenated due to the faster transit -- at a higher heart rate without cause (i.e., not due to muscular exertion), flow rates will exceed the tissues' ability to extract oxygen.
There are 5 main arteries: left carotid (left side head & neck), right carotid (right side head & neck), left subclavian (left shoulder & arm), right subclavian (right shoulder & arm), and the descending aorta (rest of body). The descending aorta is very large. The arteries are sized such that they have approximately the same flow rates, thus 1 minute is as good an approximation of the time for circulation to the brain as it is for circulation to the rest of the body.
Thus, as long as the heart beats, the brain will continue to receive oxygenated blood for about 1 minute. It's only after 1 minute that the brain will begin to signal severe air hunger. That correlates well with experience: If you forcefully exhale and then suspend breathing, you can fairly easily pass 45 seconds before air hunger discomfort begins.
The best that I can figure, the people who say less than 1 minute are using references in which the heart stops beating altogether (blood stops flowing), which is quite a different issue -- sudden loss of blood flow is not the issue in this case.
So my best estimate is that 1-1/2 minutes is about right for passing out due to oxygen starvation.
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
undoubtedly
that is your opinion
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markfilipak
8 years ago
that is your opinion
That is my surmise. Why else would someone pass out after only 15 seconds?
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
That is my surmise
exactly
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markfilipak
8 years ago
I give up. You don't seem amenable to argument. Has nothing I've written made any impression on you? Or are you swayed only by authorities like Anna Gosline? How can you know that what she wrote even happened? In contrast, you can verify everything I wrote.
I surmise this explains why I am a scientist and you are not.
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
Oh forgive me for being swayed by somebody having experienced this versus somebody who claims surmises based on their alleged scientific credentials.
Stating you are a scientist doesn't make you one. Publish it in scientific american. Then we can talk.
There are standards on that magazine that is why you are not published and she is perhaps.
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markfilipak
8 years ago
I'm not surmising about blood flow rates and the time to oxygen starvation. I'm surmising that the technician fainted. People under stress do it all the time. It's the only plausible explanation.
Power to the sheeple.
PS: I have a Bachelor of Science degree from Ohio State University (1977). I had a year of physics plus a year of advanced physics. Plus 30 years of experience. I'm now retired.
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If polar bears can't stand the change, they should go back to where they came from.
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shurbanm
8 years ago
yep and it's a surmise. your surmise.
sur·mise
verb
sərˈmīz/
1.
suppose that something is true without having evidence to confirm it.
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markfilipak
8 years ago
Thank you for that. Hmmm... "surmise" is the wrong word. I learned something today! That's good because I use "surmise" a lot and it's not at all appropriate to what I want to convey.
"Deduce" would be the more correct word. From the evidence I've presented, I deduce that the technician probably fainted because it's highly improbable that he would have blacked out from lack of oxygen in only 15 seconds.
I stand corrected.
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If polar bears can't stand the change, they should go back to where they came from.
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markfilipak
8 years ago
Well, you wrote: "You seem to be unclear about the physics involved." I proved that I'm not unclear about the physics. You have not and cannot rebut it. So, rather than continue in a pissing contest with you, I bid you farewell.
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If polar bears can't stand the change, they should go back to where they came from.
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