Human in outer space without space suit

[smallphi]

I recently saw the movie 'Sunshine' where they send a mission to detonate a bomb and save the Sun from dying. In one of the scenes, two astronauts had to cover a distance in the outer space but they didn't have space suits available. They wrapped themselves in some kind of foil and the whole trip in outer space took them several seconds till they got in the space station.

Is that physically possilbe? Can a human body survive a few seconds in outer space, just protected by a foil wrap?

Another problem would be the pressure - the human body is designed to function under air pressure of 1 atmosphere. Wouldn't the blood vessels burst out in outer space due to the lack of such external pressure?

 

[mgb_phys]

Is that physically possilbe? Can a human body survive a few seconds in outer space, just protected by a foil wrap?

Yes - you get frostbite/sunburn and a few broken blood vessels in your eyes and lungs.

Wouldn't the blood vessels burst out in outer space due to the lack of such external pressure?

Ever sucked the air out of a bottle to get your lips to stick into it as a kid?
Or had someone else expose a part of your skin to a vacuum as an older kid (see hickey).

1 atmosphere is only 15PSI, your skin is quite strong - you probably don't want to hold your breath, lungs aren't that strong.

 

[smallphi]

Yes I remember one of the astronauts said to 'exhale slowly' during the flight in outer space. At the time I thought that was weird remark but aparently it was meant to protect the lungs from zero outer pressure.

Has anyone ever flawn in outerspace without suit or these are just theoretical considerations?

I calculated what would the thermall losses be without the foil, assuming skin surface of 2m^2, skin temperature of 300K, and Stephan-Boltzmann law of a blackbody radiator. The austronaut would loose something like 1kJ/second. For 10 seconds, he would lose 10kJ. Such a nutritional energy is contained in less than a gram of carbohydrates.

That makes me wonder was the foil-wrap really necessary to protect from loss of heat. Supposedly it will reflect part of the thermal radiation back, but on the other hand, at places where the foil is touching skin it actually increases the thermal conductivity to outer space.

 

[mgb_phys]

Tricky, if you hold your breathe you are likely to rupture a long, they don't expand to twice their original size. But if you breath out you will quickly lose conciousness as the olxygen in your blood diffuses into vacuum.
Best thing is probably to wrap your chest in duct tape and hold your breath!

 

[smallphi]

Another problem would be the 'decompression sickness' where the nitrogen dissolved in blood will start to form bubbles under the low pressure.

 

[mgb_phys]

Probably not - with a vacuum in the lungs the pressure difference will extract all the dissolved gas from the blood very efficently so bubbles forming isn't a big problem.
Remember you are only 1atm over-pressure.

 

[smallphi]

I found some article explaining all the effects: http://www.damninteresting.com/?p=741

When the human body is suddenly exposed to the vacuum of space, a number of injuries begin to occur immediately. Though they are relatively minor at first, they accumulate rapidly into a life-threatening combination. The first effect is the expansion of gases within the lungs and digestive tract due to the reduction of external pressure. A victim of explosive decompression greatly increases their chances of survival simply by exhaling within the first few seconds, otherwise death is likely to occur once the lungs rupture and spill bubbles of air into the circulatory system. Such a life-saving exhalation might be due to a shout of surprise, though it would naturally go unheard where there is no air to carry it.

In the absence of atmospheric pressure water will spontaneously convert into vapor, which would cause the moisture in a victim's mouth and eyes to quickly boil away. The same effect would cause water in the muscles and soft tissues of the body to evaporate, prompting some parts of the body to swell to twice their usual size after a few moments. This bloating may result in some superficial bruising due to broken capillaries, but it would not be sufficient to break the skin.

Within seconds the reduced pressure would cause the nitrogen which is dissolved in the blood to form gaseous bubbles, a painful condition known to divers as "the bends." Direct exposure to the sun's ultraviolet radiation would also cause a severe sunburn to any unprotected skin. Heat does not transfer out of the body very rapidly in the absence of a medium such as air or water, so freezing to death is not an immediate risk in outer space despite the extreme cold.

For about ten full seconds– a long time to be loitering in space without protection– an average human would be rather uncomfortable, but they would still have their wits about them. Depending on the nature of the decompression, this may give a victim sufficient time to take measures to save their own life. But this period of "useful consciousness" would wane as the effects of brain asphyxiation begin to set in. In the absence of air pressure the gas exchange of the lungs works in reverse, dumping oxygen out of the blood and accelerating the oxygen-starved state known as hypoxia. After about ten seconds a victim will experience loss of vision and impaired judgement, and the cooling effect of evaporation will lower the temperature in the victim's mouth and nose to near-freezing. Unconsciousness and convulsions would follow several seconds later, and a blue discoloration of the skin called cyanosis would become evident.

At this point the victim would be floating in a blue, bloated, unresponsive stupor, but their brain would remain undamaged and their heart would continue to beat. If pressurized oxygen is administered within about one and a half minutes, a person in such a state is likely make a complete recovery with only minor injuries, though the hypoxia-induced blindness may not pass for some time. Without intervention in those first ninety seconds, the blood pressure would fall sufficiently that the blood itself would begin to boil, and the heart would stop beating. There are no recorded instances of successful resuscitation beyond that threshold.

Though an unprotected human would not long survive in the clutches of outer space, it is remarkable that survival times can be measured in minutes rather than seconds, and that one could endure such an inhospitable environment for almost two minutes without suffering any irreversible damage. The human body is indeed a resilient machine.

 

[mgb_phys]

Not sure why the article is convinced that the lungs will efficently remove O2 but allow N2 to form bubbles - the pressure in the blood isn't going to drop very much.
Anyway there is current opinion in the diving medicine community (at least when I used to dive actively) that 'the bends' is more due to air leaking into the blood from micro tears in the lungs (micro air embulisms) than classical dissovled gas -> bubble model.

Also a good summary here http://www.sff.net/people/geoffrey.landis/vacuum.html
The original Nasa page seems to have gone in the great Nasa cull of anything useful on their public sites!

 

[joema]

...two astronauts had to cover a distance in the outer space but they didn't have space suits available. They wrapped themselves in some kind of foil and the whole trip in outer space took them several seconds till they got in the space station...Is that physically possilbe? Can a human body survive a few seconds in outer space...

Yes you can survive, especially if the vacuum exposure is planned. E.g, the Apollo spacecraft used a 5 psi pure O2 environment, as do all space suits today. This eliminates any concern over decompression sickness ("the bends").

In a 2001 "open the pod bay doors, Hal" situation, the astronaut would dial down the pure O2 environment to around 1 psi before blowing the hatch. This greatly reduces the injury from barotrauma (sudden pressure decrease).

In such a situation you might have 15 sec of useful consciousness.

OTOH if the spacecraft has a 14.7 psi N2/O2 cabin and has sudden, unexpected pressure loss, the chances are very poor. The shock (barotramua) of sudden depressurization from 14.7 psi can stun and disorient.

 

[mgb_phys]

The shock (barotramua) of sudden depressurization from 14.7 psi can stun and disorient.

Fortunately the screaming that accompanies an explosive decompression is an efficent method of depressurising the lungs!

 

[cadnr]

How rapid a decompression to 0 atm can the ear drums withstand before rupturing? Would the eustachian tubes be wide enough to allow instantaneous pressure equilibration?

 

[mgb_phys]

If your mouth is open (see screaming above) and your tubes aren't blocked then it reaches equilibrium pretty quickly, there isn't much volume of air behind your ear drums to remove.
They can also survive a 1bar pessure difference without rupturing (although it hurts!)

 

[TVP45]

Yes I remember one of the astronauts said to 'exhale slowly' during the flight in outer space. At the time I thought that was weird remark but aparently it was meant to protect the lungs from zero outer pressure.

Has anyone ever flawn in outerspace without suit or these are just theoretical considerations?

I calculated what would the thermall losses be without the foil, assuming skin surface of 2m^2, skin temperature of 300K, and Stephan-Boltzmann law of a blackbody radiator. The austronaut would loose something like 1kJ/second. For 10 seconds, he would lose 10kJ. Such a nutritional energy is contained in less than a gram of carbohydrates.

That makes me wonder was the foil-wrap really necessary to protect from loss of heat. Supposedly it will reflect part of the thermal radiation back, but on the other hand, at places where the foil is touching skin it actually increases the thermal conductivity to outer space.

Did they wrap shiny side out or matte side out?

 

[_Mayday_]

It would be possible but I wouldn't advise it. I am sure if it had no effect on the human body, people wouldn't bother with the whole suit thing. What I don't get is its freezing yet you can get sunburn? Its quite hard to imagine being freezing and yet having the sun beating down on you?...

 

[mgb_phys]

It would be possible but I wouldn't advise it. I am sure if it had no effect on the human body, people wouldn't bother with the whole suit thing. What I don't get is its freezing yet you can get sunburn? Its quite hard to imagine being freezing and yet having the sun beating down on you?...

You don't freeze, although it is cold in space there is nothing to carry the heat away - it's like the ultimate thermos flask!

Sunburn is a major problem. Remember sunburn isn't heat - it's UV light. There is a big sun up there and no atmosphere or ozone layer to protect you.
On a sunny day on a mountain you can sun burn on unprotected skin in minutes - I've done it in Hawaii at 14,500ft , it wasn't cold so I only had a t shirt on. In space you can probably get severe burns in seconds.

 

[_Mayday_]

Oh yeah, an example would be like when you go skiing you can get sunburnt and it can be freezing. Thanks.

 

[joema]

...What I don't get is its freezing yet you can get sunburn?...

Sunburn and freezing are a moot point for the discussed scenario: human vacuum survival.

Under optimal conditions you'd have about 15 sec. of useful consciousness. After that you're dead, unless another suited individual dragged your unconscious body along.

Also, the 15 sec isn't all exposed to solar radiation. You have to open the hatch of your ship, go through space, enter the hatch of the destination ship, then close the door and start repressurization.

All of that subtracts from the approx. 15 sec. You'd be exposed to solar radiation for (at most) 5-10 sec. Also the scenario is without a pressure suit, not unclothed, which would give some UV protection.

The total solar energy above the atmosphere is about 1350 watts/m^2, roughly 1.5% of this in the UV-B range, or 20 watts/m^2: http://exp-studies.tor.ec.gc.ca/e/ozone/uv_index_definition.htm

That is roughly the UV-B radiation produced by some tanning beds (Woollons, Clingen, Price, Arlett, & Green, 1997).

You basically have about 15 sec, and even that assumes a planned event, and probably a pure O2 cabin/suit environment. After that it doesn't matter how cold or sunburned you get, as you'd be dead.

 

[Garth]

This Scientific American article might be useful: Survival in Space Unprotected Is Possible--Briefly.

Garth

 

[rbj]

be sure to disconnect/power_down the mutinous killer computer when you get back inside. maybe he'll sing "Daisy" for you as his consciousness drifts into oblivion.

 

[_Mayday_]

be sure to disconnect/power_down the mutinous killer computer when you get back inside. maybe he'll sing "Daisy" for you as his consciousness drifts into oblivion.

i've read that 5 times and it makes no more sense than it did the first time

 

[mgb_phys]

http://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_(film )