From: "Geoffrey A. Landis" <geoffrey.landis@lerc.nasa.gov>
Newsgroups: sci.space.tech
Subject: Re: survial in a vacuum
Date: 27 Jun 1998 15:54:42 GMT
Distribution: world
Message-ID: <6n34k2$2g9@sulawesi.lerc.nasa.gov>
References: <Pine.SUN.3.96.980626150903.8499A-100000@eskimo.com>

This is a topic that comes up frequently on sci.space and
rec.arts.sf.science.

The quick answers to these questions are: Clarke got it about right in
2001.  You would survive about a ninety seconds, you wouldn't explode,
you would remain conscious for about ten seconds.

The best data I have comes from _Bioastronautics Data Book_, Second
edition, NASA SP-3006, edited by James F. Parker and Vita R. West, 1973,
in the article "Chapter 1: Barometric Pressure," by Charles E. Billings. 
This chapter discusses animal studies of decompression to vacuum.  It
does not mention any human studies.

page 5, (following a general discussion of low pressures and ebullism):
"Some degree of consciousness will probably be retained for 9 to 11
seconds (see chapter 2 under Hypoxia).  In rapid sequence thereafter,
paralysis will be followed by generalized convulsions and paralysis once
again.  During this time, water vapor will form rapidly in the soft
tissues and somewhat less rapidly in the venous blood.  This evolution of
water vapor will cause marked swelling of the body to perhaps twice its
normal volume unless it is restrained by a pressure suit.  (It has been
demonstrated that a properly fitted elastic garment can entirely prevent
ebullism at pressures as low as 15 mm Hg absolute [Webb, 1969, 1970].) 
Heart rate may rise initially, but will fall rapidly thereafter. 
Arterial blood pressure will also fall over a period of 30 to 60 seconds,
 while venous pressure rises due to distention of the venous system by
gas and vapor.  Venous pressure will meet or exceed arterial pressure
within one minute.  There will be virtually no effective circulation of
blood.  After an initial rush of gas from the lungs during decompression,
gas and water vapor will continue to flow outward through the airways. 
This continual evaporation of water will cool the mouth and nose to
near-freezing temperatures; the remainder of the body will also become
cooled, but more slowly.
"Cook and Bancroft (1966) reported occasional deaths of animals due to
fibrillation of the heart during the first minute of exposure to near
vacuum conditions.  Ordinarily, however, survival was the rule if
recompression occurred within about 90 seconds. ... Once heart action
ceased, death was inevitable, despite attempts at resuscitation....
[on recompression] Breathing usually began spontaneously... Neurological
problems, including blindness and other defects in vision, were common
after exposures (see problems due to evolved gas), but usually
disappeared fairly rapidly.
"It is very unlikely that a human suddenly exposed to a vacuum would have
more than 5 to 10 seconds to help himself.  If immediate help is at hand,
although one"s appearance and condition will be grave, it is reasonable
to assume that recompression to a tolerable pressure (200 mm Hg, 3.8
psia) within 60 to 90 seconds could result in survival, and possibly in
rather rapid recovery."

Henry Spencer suggests the book by Arnauld E. Nicogossian, Carolyn L.
Huntoon and Sam L. Pool _Space Physiology and Medicine_, 2nd Edition, Lea
and Febiger, Philadelphia 1989.

Another useful reference is
"Rapid (Explosive) Decompression Emergencies in Pressure-Suited
Subjects", by Emanuel M. Roth, NASA CR-1223, circa 1968.  Its focus is on
decompression, rather than vacuum exposure per se, but it still has a lot
of good info. 

There are three cases of human exposure to vacuum worth noting.  In 1966
a technician at NASA Houston was decompressed to vacuum in a space-suit
test accident.  This case is discussed by Roth in the reference above. 
He lost consciousness in 12-15 seconds.  When pressure was restored after
about 30 seconds of exposure, he regained consciousness, with no apparent
injury sustained.

In 1960, in a balloon-jump, another vacuum exposure for longer term but
not for a whole-body exposure occurred:
"The experiment of exposing an unpressurized hand to near vacuum for a
significant time while the pilot went about his business occurred in real
life on Aug. 16, 1960.  Joe Kittinger, during his ascent to 102,800 ft
(19.5 miles) in an open gondola, lost pressurization of his right hand. 
He decided to continue the mission, and the hand became painful and
useless as you would expect.  However, once back to lower altitudes
following his record-breaking parachute jump, the hand returned to
normal."
[quoting from Leonard Gordon, _Aviation Week_,  February 13th 1996.

Finally, posting to sci.space, Gregory Bennett discussed an actual space
incident:

"Incidentally, we have had one experience with a suit puncture on the
Shuttle flights.  On STS-37, during one of my flight experiments, the
palm restraint in one of the astronaut's gloves came loose and migrated
until it punched a hole in the pressure bladder between his thumb and
forefinger.  It was not explosive decompression, just a little 1/8 inch
hole, but it was exciting down here in the swamp because it was the first
injury we've ever head from a suit incident.  Amazingly, the astronaut in
question didn't even know the puncture had occured; he was so hopped on
adrenalin it wasn't until after he got back in that he even noticed there
was a painful red mark on his hand.  He figured his glove was chafing and
didn't worry about it....  What happened: when the metal bar punctured
the glove, the skin of the astronaut's hand partially sealed the opening.
 He bled into space, and at the same time his coagulating blood sealed
the opening enough that the bar was retained inside the hole."

More details can be found in the sci.space FAQ:
http://www.cis.ohio-state.edu/hypertext/faq/usenet/space/top.html
and at a site at NASA Johnson:
http://medlib.jsc.nasa.gov/intro/vacuum.html
(which quotes liberally [and without credit] from the old discussiona on
sci.space)

________
Geoffrey A. Landis
Ohio Aerospace institute at NASA Lewis Research Center
http://www.sff.net/people/Geoffrey.Landis/

1 responses total.

I'd be more interested in how long (trained & prepared) hot-shot 
astronauts could go (kicking & without injury) - both with and without
a fairly-convenient-and-comfortable Spandex union suit.  If you're doing
much real work in space, the current state of affairs (as reflected 
above) is a huge logistical lodestone.

(Though at the rate the space program's going, maybe the genetic engineers
will have astronauts rated for 3-hour mid-day walks on the moon wearing 
2 flip-flops and carrying an umbrella before we're even back there....) 

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