Would You Really Pop Like a Balloon in a Vacuum?

If a person were suddenly placed in a vacuum, e.g.,
thrown out of a spaceship without a protective/pressure-ized
suit -- a la science fiction movies, would they really pop
like a balloon, or is this an exaggeration? What would really
happen, volumetrically speaking, to the human body?

Thanks
--
Christopher J. Wood

In article ,
Chris Wood wrote:
If a person were suddenly placed in a vacuum, e.g.,
thrown out of a spaceship without a protective/pressure-ized
suit -- a la science fiction movies, would they really pop
like a balloon, or is this an exaggeration?

It's not merely an exaggeration, it's a myth. Animal experiments, one
test-chamber spacesuit accident, and the Soyuz 11 disaster demonstrated
decades ago that nothing much happens when a person is placed in vacuum.

The first event of note is that after 10-15 seconds, he suddenly loses
consciousness due to lack of oxygen. Some uncertain time later, perhaps a
minute, the accumulated brain damage from lack of oxygen is bad enough
that he's effectively dead. (If those numbers sound short, it's because
in most comparable accidents on the ground, there is considerable air left
in the lungs, and that makes a large difference.)

Serious physical damage from the lack of pressure takes rather longer than
that. The bodies of the Soyuz 11 crew spent perhaps ten minutes in
vacuum, and looked normal enough that the recovery team started CPR.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

At the risk of putting folk off their food, would not the effect depend on
the speed of the depressurisation?

Brian

--
Brian Gaff....
graphics are great, but the blind can't hear them
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"Henry Spencer" wrote in message
...
| In article ,
| Chris Wood wrote:
| If a person were suddenly placed in a vacuum, e.g.,
| thrown out of a spaceship without a protective/pressure-ized
| suit -- a la science fiction movies, would they really pop
| like a balloon, or is this an exaggeration?
|
| It's not merely an exaggeration, it's a myth. Animal experiments, one
| test-chamber spacesuit accident, and the Soyuz 11 disaster demonstrated
| decades ago that nothing much happens when a person is placed in vacuum.
|
| The first event of note is that after 10-15 seconds, he suddenly loses
| consciousness due to lack of oxygen. Some uncertain time later, perhaps a
| minute, the accumulated brain damage from lack of oxygen is bad enough
| that he's effectively dead. (If those numbers sound short, it's because
| in most comparable accidents on the ground, there is considerable air left
| in the lungs, and that makes a large difference.)
|
| Serious physical damage from the lack of pressure takes rather longer than
| that. The bodies of the Soyuz 11 crew spent perhaps ten minutes in
| vacuum, and looked normal enough that the recovery team started CPR.
| --
| MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
| pointing, 10 Sept; first science, early Oct; all well. |



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In article ,
Brian Gaff wrote:
At the risk of putting folk off their food, would not the effect depend on
the speed of the depressurisation?

Not strongly. Really fast depressurization may cause various bits of
unpleasantness because there won't be time for pressures to equalize in
places like your ears, but it still won't make you explode.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

On Mon, 10 Nov 2003 09:46:16 -0500, "Chris Wood"
wrote:

If a person were suddenly placed in a vacuum, e.g.,
thrown out of a spaceship without a protective/pressure-ized
suit -- a la science fiction movies, would they really pop
like a balloon, or is this an exaggeration? What would really
happen, volumetrically speaking, to the human body?

Thanks

There is one problem missed by the answer. As any scuba diver will
know, a sudden decrease in pressure around the lungs will cause them
to expand and possibly rupture - hence the rule about never holding
your breath. A 3% increase in volume is normally considered enough to
cause rupture. If it is assumed that the last breath of air filled the
lungs with air at normal air pressure (note in a US space suit the
pressure is only 1/3 of normal air pressure but in a capsule it's
close to normal) then a sudden depressurisation would cause a lung
rupture if the person attempted to hold their breath - this would lead
to massive air embolisms and death even if the person was returned to
normal pressure and plenty of oxygen.

To survive the accident the hapless victim would need to make sure
that their airways were open and their lungs emptied as quickly as
possible. Even then it is quite possible that they would develop
decompression sickness from the bubbles of dissolved nitrogen that
would appear in their blood. Given the short period of vacuum
(assuming they survive the exposure) this would probably be minor.
There is also a danger of eardrum rupture, and considerable sinus pain
from the sudden decrease in pressure.

David Reidy

[Posted via Victory Crayne]

Really fast depressurization may cause various bits of
unpleasantness because there won't be time for pressures to equalize in
places like your ears, but it still won't make you explode.

The "bends" would be an issue, but as you say, no "explosion"...

In article ,
Velovich03 wrote:
Really fast depressurization may cause various bits of
unpleasantness because there won't be time for pressures to equalize in
places like your ears, but it still won't make you explode.

The "bends" would be an issue, but as you say, no "explosion"...

As I understand it, it's unlikely that you'd get major symptoms from the
bends in the 10-15s you have before you lose consciousness. (I also think
it's unlikely that such symptoms would be your main worry even if you did
get them!).

Mundane and prosaic though it sounds, the dominant problem of a human
exposed to vacuum is simply lack of oxygen. The other effects all seem to
be either reversible or at least nonlethal on the time scale required for
you to die of anoxia.
--
MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer
pointing, 10 Sept; first science, early Oct; all well. |

"Brian Gaff" wrote in message ...
At the risk of putting folk off their food, would not the effect depend on
the speed of the depressurisation?

No. The human body's internal pressure is not high enough to cause an
explosion, and human tissue is both elastic and soft enough to "ride
out" a very substantial, very rapid pressure change.

Note the human body's response to very sharp pressure waves:

http://www.ciar.org/ttk/hew/hew/Nwfaq/Nfaq5.html

Section 5.6.2...

"As a general guide, city areas are completely destroyed ... by
overpressures of 5 psi, with heavy damage extending out at least to
the 3 psi contour.

"Humans are actually quite resistant to the direct effect of
overpressure. Pressures of over 40 psi are required before lethal
effects are noted. This pressure resistance makes it possible for
unprotected submarine crews to escape from emergency escape locks at
depths as great as one hundred feet (the record for successful escape
is actually an astonishing 600 feet, representing a pressure of 300
psi). Loss of eardrums can occur, but this is not a life threatening
injury."

There will be local problems with the bends and ruptured ear drums,
but for the most part, living tissue can expand, contract, and vent
rapidly enough to handle a sharp pressure change.

Mike Miller, Materials Engineer