

Survival in Space Unprotected is Possible - sethito
http://www.scientificamerican.com/article.cfm?id=survival-in-space-unprotected-possible

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lmkg
Explosive decompression won't happen in space, under normal circumstances. It
is a thing that can happen, but it requires a drop larger than 1atm -> 0atm to
overcome the strength of human skin. People have literally exploded from a
pressure drop, but they were deep-sea divers in a decompression chamber that
lost integrity and went from 9atm -> 1atm[1], a drop 8x larger than going from
sea-level atmospheric pressure to vacuum.

From the article, it sounds like some of the symptons resemble "the bends"
divers have when they surface too quickly. The cause of the bends is the
change in pressure no longer being sufficient to keep the nitrogen dissolved
in your blood, dissolved in your blood. Bubbles in blood veins are bad news.

Pretty much all of the issues with vacuum have to do with liquids becoming
gases, and unsealed gases wanting to disperse. I have to imagine it's goddamn
_weird_ feeling the water evaporate off your eyeballs.

[1]
[http://en.wikipedia.org/wiki/Byford_Dolphin#Diving_bell_acci...](http://en.wikipedia.org/wiki/Byford_Dolphin#Diving_bell_accident)

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tokenadult
A famous scene in the 1968 film _2001: A Space Odyssey_ showed this. (The
actor, Keir Dullea, almost was badly injured in the shot showing him entering
the spaceship airlock without his helmet on, by the way.) But as the article
points out, such survival is only

"for at least a couple of minutes. Not that you would remain conscious long
enough to rescue yourself, but if your predicament was accidental, there could
be time for fellow crew members to rescue and repressurize you with few ill
effects."

So be sure to practice a buddy system if you are going into outer space
without full protective gear on at all times. There's a reason that the full
title of the article submitted here is "Survival in Space Unprotected Is
Possible--Briefly."

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jessriedel
2 minutes isn't much time to accomplish anything in a space suit. Your buddy
needs to recognize what's happened, get to you, drag you into the airlock, and
repressurize the airlock. Unless this happens directly next to the airlock
door, I think you're done for.

~~~
rsofaer
Your conscious time is more like 15 seconds, according to the article. All
you're going to accomplish is hitting a panic button.

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kyllo
As a dog lover, their descriptions of the animal subjects studies they did
made me cringe.

>During their exposure, they were unconscious and paralyzed. Gas expelled from
their bowels and stomachs caused simultaneous defecation, projectile vomiting
and urination. They suffered massive seizures. Their tongues were often coated
in ice and the dogs swelled to resemble "an inflated goatskin bag," the
authors wrote.

Horrible. If this knowledge is going to actually directly save human lives,
and there's no better way, well OK then, but this is just a terrible, horrible
thing to do to a creature like a dog or a chimpanzee.

~~~
HCIdivision17
I think you can be reassured that the only better way is to place people in
hard vacuum, which most would assume too risky. A bit of our knowledge was
gathered the traditional industrial way (via reporting on people getting
hurt), but it looks like the animal testing was likely timely and informed the
risks at stake.

I wondered just how many dogs were involved, and I found the following link:
[http://triscience.com/Animals/Muscle/experimental-animal-
dec...](http://triscience.com/Animals/Muscle/experimental-animal-
decompressions-to-a-near-vacuum-environment/doculite_view) It notes the test
group was 125, with tests done in groups of 6. My impression is that their
experience wasn't a waste, and was a benchmark study for decades.

While trying to find the original study, I stumbled across another that goes
into some further detail.
<http://cousin.pascal1.free.fr/AVMA%20etude%20decom.pdf> I don't have the
constitution to read much medical research, but the impression is that the
experience is markedly short. Physiologically decompression is pretty awful,
but the subject doesn't suffer consciously. Hopefully that's a bit reassuring
that the animals did not experience any horror film-like agony before blacking
out (though it would be uncomfortable, to be sure).

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Gravityloss
Yarchive comes to help.

<http://yarchive.net/space/science/man_in_vacuum.html>

There has been some real quality writing by certain individuals in the
sci.space.* newsgroups about this and many other subjects (many of which are
popular myths). You can learn a lot if you're interested in this kind of
stuff.

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js2
The lack of oxygen is the biggest problem I'd gather:

<https://www.youtube.com/watch?v=WTNX6mr753w> (hypoxia in an altitude chamber
from "how to kill a a human being" documentary)

I guess radiation exposure is another big one.

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error54
What the article fails to mention is that space is cold. Really, really cold
averaging -454.81 Fahrenheit[1] making concerns about oxygen or water pressure
irrelevant. The article should have been called "Survival in Vacuum
Unprotected Possible."

1 -
[http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980301b....](http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980301b.html)

~~~
silvio
Space is for all practical purposes a vacuum, thus the only cooling effect
would be by radiation, given that the body wouldn't be in contact with
anything around it, as opposed to what happens on the ground where it is
surrounded by air or water in the sea. In these conditions, the change in
temperature takes a long time.

As stated in the linked article:

"If we put a thermometer in darkest space, with absolutely nothing around, it
would first have to cool off. This might take a very very long time. Once it
cooled off, it would read 2.7 Kelvin."

So, the vacuum really is the main concern. You'd be long dead before you start
getting cold.

~~~
gmaslov
Indeed. A living human probably generates more heat from the normal bodily
processes than can be radiated away in space. For this reason spacesuits are
equipped with coolers, not (AFAIK) heaters.

~~~
error54
Thanks guys! I didn't even think about there being nothing around to transfer
heat away the body. I would have figured that the fact that water boils and
then freezes in space would mean (humans being mostly water) that a person
would expire rather quickly unprotected.

~~~
HCIdivision17
I came across a neat explanation of why we don't freeze immediately: our
skin's pretty good at keeping the wet parts of us inside! When I had been
curious about this a few years ago, this was the thing that convinced me of
it. After all, in order for the water in us to freeze, the higher energy water
molecules need to go somewhere, right? (Of course, it's possible very small
gas bubbles will dissolve into your blood, and that _will_ quickly expire a
person, but as noted elsewhere in this thread the pressure drop from atmo to
vacuum is less than that normally experienced by divers.)

Also, I have covered a vacuum flange with my hand. Heckuva hickie, but
otherwise harmless. Smarts a bit with a dash of bruising, but the skin holds
up remarkably well.

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Houshalter
Wtf is with the only two animal experiments being on dogs and chimps? I am ok
with animal research, but on dogs? Or chimps which are closer to humans than
any other animal? This research isn't even necessary. Everyone already knew
going into the vacuum of space was bad.

~~~
daeken
> Everyone already knew going into the vacuum of space was bad.

That line of thinking leads to a complete lack of actual science. As the
article points out: going into the vacuum of space is _nowhere near_ as bad as
is conventionally thought. That's an incredibly valuable finding, and it gives
us the information we need to create effective safety and recovery mechanisms
in space.

~~~
Houshalter
Well after you tried it on the first 5 dogs, why go for 120 more? And then 6
chimps after that? (I think those are what the numbers were IIRC.) And
regardless the knowledge isn't terribly useful. We have a slightly more
accurate timescale on how quickly people die in a certain (very rare and
specific) way. And it's still not enough to actually do anything
realistically.

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ricardobeat
Looks like Battlestar Galactica got it right then.

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jesseb
They seem to have forgotten to mention the fact that the radiation levels
would exceed lethal dosages in a matter of seconds.

~~~
rdtsc
Is it all alpha radiation? Otherwise, astronauts and cosmonauts that did space
walks are still alive. Don't think space suits are fantastic gamma ray
shields, but I may be wrong...

