Text 23808, 90 rader
Skriven 2008-11-17 12:52:42 av Dan Ceppa (1:138/666.0)
     Kommentar till en text av Ross Cassell
Ärende: Spacewalks in the nude (was: Loyalties)
===============================================
-> On 17 Nov 08  05:08:02, Ross Cassell got back to shannon talley 
-> Re: Spacewalks in the nude (was: Loyalties)

 st> exploading right away and within 30 seconds, one would be 'beyond' the
 st> help of any known medicine or procedure.  Your post changes my
 st> paradigm.  How accurate is your info?

 RC> The gases in your blood and tissues would immediately come out of
 RC> suspension and expand, your blood would boil, death would come sooner
 RC> than what Dan claims. 

I'm not claiming anything:  

Can You Survive in Space Without a Spacesuit?The sci-fi movie Sunshine gets it
almost right.
By Morgan SmithPosted Wednesday, Aug. 1, 2007, at 5:33 PM ET

Astronaut Bruce McCandless during an extra-vehicular activity.  Click image to
expand.Astronaut Bruce McCandless during an extra-vehicular activityIn the new
sci-fi film Sunshine, an astronaut named Mace must leave his spacecraft
without a protective suit.  He makes it through his exposure with only a case
of frostbite. Could you really survive outer space without a suit?
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Yes, for a very short time.  The principal functions of a spacesuit are to
create a pressurized, oxygenated atmosphere for astronauts, and to protect
them from ultraviolet rays and extreme temperatures.  Without it, a
spacewalker would asphyxiate from the lack of breathable air and suffer from
ebullism, in which a reduction in pressure causes the boiling point of bodily
fluids to decrease below the body's normal temperature.  Since it takes a bit
of time for these things to kill you, it's possible to make it through a very
quick stint in outer space.
Related in Slate
The Explainer figured out the role of a "planetary protection officer." Greg
Easterbrook blasted NASA's grandiose budgeting.  David Owen wondered about the
value of the space shuttle.  Chris Suellentrop said space travel shouldn't be
glorious, it should be safe.

At most, an astronaut without a suit would last about 15 seconds before losing
conciousness from lack of oxygen.  (That's how long it would take the body to
use up the oxygen left in the blood.) Of course, on Earth, you could hold your
breath for several minutes without passing out.  But that's not going to help
in a vacuum.  In fact, attempting to hold your breath is a sure way to a quick
death.  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.  Scuba divers are also at risk for air embolism; they're
instructed not to hold their breath as they ascend from the deep sea.

An astronaut who fell unconscious from lack of oxygen would last for a few
minutes more before dying from asphyxiation or the effects of the pressure
reduction.  Ebullism would result in the formation of bubbles in the moisture
found in the eyes, mouth, and skin tissue.  One NASA test subject who survived
a 1965 accident in which he was exposed to near-vacuum conditions felt the
saliva on his tongue begin to boil before he lost consciousness after 14
seconds.
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In the movie, Mace takes the precaution of wrapping himself in insulation torn
from the walls of the spacecraft he's leaving.  This might provide some
protection against temperatures in space that can run from minus-200 to 200
degrees Fahrenheit.  It might also ward off ultraviolet-related skin damage
during a short jump through space.

What about the frostbite?  That's actually the least plausible result of
Sunshine's suitless spacewalk.  The cold wouldn't cause Mace too much harm in
just 15 seconds, even if he encountered the very lowest temperatures in space.
That's because heat leaves the body very slowly in a vacuum.  The more likely
damage would be a "space hickey"-caused from the swelling and bursting of the
skin's small blood vessels-which would look more like the effects of
freeze-drying a wart than a case of frostbite.

Got a question about today's news? Ask the Explainer.

Explainer thanks Brandi Dean of NASA and Geoffrey Landis of the NASA John
Glenn Research Center.  Thanks also to reader Matt Burden for asking the
question.



--- OMX/Blue Wave/DOS v2.30
 * Origin: Soundly on the Fault Line (1:138/666.0)