Survival in Space Unprotected is Possible | Hacker News Reader

Survival in Space Unprotected is Possible

scientificamerican.com

52 pointssethito30 comments

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...

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."

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.

Or patch the hole, if there is a hole. But your points is valid that its not a lot of time.

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

Or, they throw you into a rescue ball. http://en.wikipedia.org/wiki/Personal_Rescue_Enclosure

Event Horizon from 1997 also had a scene where someone survived a short trip through space.

That was the first thing I thought of when the author mentioned exploding eyeballs.

Also the movie Sunshine.

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.

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... 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).

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.

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.

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....

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.

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.

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.

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.

There's an awful scene in the film 'Mission to Mars' where Tim Robbins removes his helmet in space, and his head instantly freezes. No, no, no!

How does vacuum (the absence of matter) have a temperature?

Outer space isn't a perfect vacuum.

http://en.wikipedia.org/wiki/Vacuum#Outer_space

Even if there were no atoms, you must consider the electromagnetic field (or photons if you want to think that you have particles).

If you have a perfectly empty box (with total vacuum inside) and the walls have some temperature (for example 2.7K) then, after a while, inside the box will appear the electromagnetic field with the blackbody radiation of the walls temperature.

It's convenient to assign properties to the electromagnetic field, in this case the temperature. And the correct temperature of the electromagnetic field inside the box is the same as the temperature of the walls.

And the best thing is that the walls are not necessary! You can assign a temperature to the universe background radiation. If the distribution of frequencies of the electromagnetic field is equal to the blackbody radiation of a 2.7K blackbody, then you can think that the temperature of the electromagnetic field is also 2.7K.

More details: http://en.wikipedia.org/wiki/Photon_gas

The statement "space is cold" doesn't make much sense, since space, being a vacuum, is lacking any _thing_ to have a temperature at all. What little matter does exist in the vacuum of space is not going to conduct any significant heat from your warm body. An ordinary "space blanket" would keep you quite warm. Until you suffocated, of course.

I worked on vacuum systems. Space is not cold, nor hot, nor happy. It's sort of the wrong way of looking at it.

Vacuum isn't. It is a terrible conductor of heat. So bad, that after 15 minutes a very small battery powered pen camera started to red on the edges of the video: it was starting to heat up! The only way to cool off is via radiation, which takes quite a while. If you had a large array of very conductive, high surface area material, then you could get cold. But our skin isn't like that. Rather, it's wet and insulative. The membranes that are wet immediately suffer evaporative cooling, but once frozen will have to sublime to cool any more, which is slow. The skin is dead on the outside and has layers of insulation in the form of water and fat.

No, the research, testing, and industrial accident reports show that you die from oxygen deprivation. (And you can find vacuum labeled as an asphyxiate, since inhaling it is deadly...)

EDIT: I should note that the temperature of the vacuum really is very low. That's not disputable. But there just aren't enough atoms in a vacuum for it to feel cold. It's one of those times our intuition about units sort of sets us up for failure: temperature is an average kinetic energy of each particle, and normally there are enough particles to matter. In a vacuum there usually aren't. (I'm lying of course: high energy plasmas can definitely heat something up given a few hours.)

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.

> 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.

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.

Looks like Battlestar Galactica got it right then.

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

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...

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