8 ASTRONOMY • FEBRUARY 2018t the end of some sci-fi
movies (think To t a l
Recall or Outland),
the bad guy is
pushed out the
spaceship’s airlock. You know
what happens next. He explodes.
But such scenes do not
match the reality of space. In
the 1960s, NASA built a bunch
of altitude chambers to mimic
the hostile environment of low
air pressure. Volunteers experi-
enced the conditions found at
various altitudes, and a few
animal tests — thankfully not
very many — were conducted
with even lower pressures.
The results let scientists learn
how bodies would respond to
sudden depressurization, and
were proven correct in later acci-
dents. (Fortunately, none of the
outcomes included exploding.)
In 1965, a technician testing a
new space suit in an altitude
chamber was exposed to a near-
total vacuum when a faulty valve
popped and all the air immedi-
ately rushed out. In exactly 14
seconds, the man lost conscious-
ness and collapsed. Happily, he
was being monitored — air was
promptly reintroduced, and he
regained consciousness without
any apparent harm.
A few years later, another
technician was trapped in a
faulty altitude chamber. He too
lost consciousness in about 15
seconds and started turning
blue. His life was saved when a
manager kicked in one of the
machine’s gauges, breaking the
seal and letting air rush in.
When an animal or human
body is suddenly exposed to the
vacuum of space, a number ofSTRANGEUNIVERSE
Don’t believe everything you see in the movies.BY BOB BERMANNext time you’re
in space...
A
injuries begin immediately. At
first they are minor, but they
quickly add up to become life
threatening. The first and most
visible is the instant expansion
of gases in the lungs and diges-
tive tract. A 1965 study at the
Brooks Air Force Base in
San Antonio proved that dogs
exposed to a near-total vacuum
always survived if they were
“rescued” (meaning pressure
was restored) within 1.5 min-
utes. However, they became
unconscious almost immedi-
ately, with gas expelled from
their bowels and stomachs,
resulting in simultaneous def-
ecation, projectile vomiting, and
urination. It all looked worse
than it was: They had seizures,
their tongues were coated in ice,
and the animals swelled up likeballoons. Yet even partial repres-
surization made the dogs shrink
back down and begin to breathe.
When full pressure was restored,
they were walking after 10 to 15
minutes, and an odd blindness
that had befallen them wore off
after a few minutes more.
But dogs kept in a vacuum
just slightly longer, two minutes
or more, usually died. Oddly,
chimpanzees withstood longer
periods in a vacuum. They lived
after up to 3.5 minutes in space-
like conditions without any
later impairment in function.
Human accidents showed
similar lack of long-termimpairment. That technician
with the faulty space suit later
said his last memory before
blacking out was of moisture on
his tongue boiling. Indeed, we
know that water instantly boils
in space, even at room tempera-
ture. At any height above about
63,000 feet (19,000 meters) —
called the Armstrong limit or
Armstrong’s line (no relation to
Neil, but named after Harry
Armstrong, who founded the
U.S. Air Force’s Department of
Space Medicine in 1947) —
water boils below body tempera-
ture. Eye and tongue moisture
boils away, and no amount of
externally supplied breathing airpressure (such as via a positive
pressure oxygen system) will
keep a person conscious. Blood
won’t boil because it’s sealed
under pressure within arteries
and veins, but nitrogen gas bub-
bles quickly form in the blood,
and these start accumulating
until they stop the heart in two
to three minutes. At the same
time, the absence of pressure
outside the skin pulls it out-
ward, creating a partial vacuum
around muscles and organs so
that water there speedily evapo-
rates, contributing to the swell-
ing of the victim.
An astronaut finding herselfin sudden decompression should
first exhale; otherwise, the lungs
will probably rupture and inject
air bubbles into the circulatory
system. This lifesaving breath
out will be followed by 10 to 15
seconds of useful consciousness.
This is the only time available to
her to save her own life.
Of course, space has other
perils, too, like the angry red
sunburn one would get in just
two minutes of direct skin expo-
sure to solar radiation (includ-
ing the fearsome UV-C we never
receive on Earth’s surface). On
the other hand, the sci-fi sce-
nario of the unprotected astro-
naut freezing solid (Sunshine,
Mission to Mars) would not hap-
pen, at least not for a long while,
because body heat cannot easily
go anywhere in a vacuum. Space
acts like a thermos container. It
preserves body heat, so staying
warm is not on the astronaut’s
immediate “to do” list. Only the
cooling induced by the sudden
water evaporation from mouth,
nose, and eyes would be notice-
able, creating an instant coating
of ice in these areas.
Bottom line: If this ever hap-
pens to you, breathe out, use
your 10 to 15 seconds wisely,
and know that if your friends
bring you in within 90 seconds,
even though you’ll be uncon-
scious, you should live to tell
about it. There. Not so bad.BROWSE THE “STRANGE UNIVERSE” ARCHIVE AT http://www.Astronomy.com/Berman.Contact me about
my strange universe by visiting
http://skymanbob.com.Ed White was the first American to perform an extravehicular spacewalk, which lasted
23 minutes. Without a cozy space suit like the one he wore, you could expect to last
about 90 seconds in the vacuum of space. NASAIn the 1960s, NASA built a bunch of
altitude chambers to mimic the
hostile environment of low air pressure.