"Robert A. Heinlein - Have Space Suit Will Travel" - читать интересную книгу автора (Heinlein Robert A)

First I swabbed it out with Clorox to kill the locker-room odor. Then I
got to work on the air system.
It's a good thing they included that manual; most of what I thought I
knew about space suits was wrong.
A man uses around three pounds of oxygen a day -- pounds mass, not
pounds per square inch. You'd think a man could carry oxygen for a month,
especially out in space where mass has no weight, or on the Moon where three
pounds weigh only half a pound. Well, that's okay for space stations or ships
or frogmen; they run air through soda lime to take out carbon dioxide, and
breathe it again. But not space suits.
Even today people talk about "the bitter cold of outer space" -- but
space is vacuum and if vacuum were cold, how could a Thermos jug keep hot
coffee hot? Vacuum is nothing -- it has no temperature, it just insulates.
Three-fourths of your food turns into heat -- a lot of heat, enough each
day to melt fifty pounds of ice and more. Sounds preposterous, doesn't it? But
when you have a roaring fire in the furnace, you are cooling your body; even
in the winter you keep a room about thirty degrees cooler than your body. When
you turn up a furnace's thermostat, you are picking a more comfortable rate
for cooling. Your body makes so much heat you have to get rid of it, exactly
as you have to cool a car's engine.
Of course, if you do it too fast, say in a sub-zero wind, you can freeze
-- but the usual problem in a space suit is to keep from being boiled like a
lobster. You've got vacuum all around you and it's hard to get rid of heat.
Some radiates away but not enough, and if you are in sunlight, you pick
up still more -- this is why space ships are polished like mirrors.
So what can you do?
Well, you can't carry fifty-pound blocks of ice. You get rid of heat the
way you do on Earth, by convection and evaporation -- you keep air moving over
you to evaporate sweat and cool you off. Oh, they'll learn to build space
suits that recycle like a space ship but today the practical way is to let
used air escape from the suit, flushing away sweat and carbon dioxide and
excess heat -- while wasting most of the oxygen.
There are other problems. The fifteen pounds per square inch around you
includes three pounds of oxygen pressure. Your lungs can get along on less
than half that, but only an Indian from the high Andes is likely to he
comfortable on less than two pounds oxygen pressure. Nine-tenths of a pound is
the limit. Any less than nine-tenths of a pound won't force oxygen into blood
-- this is about the pressure at the top of Mount Everest.
Most people suffer from hypoxia (oxygen shortage) long before this, so
better use two p.s.i. of oxygen. Mix an inert gas with it, because pure oxygen
can cause a sore throat or make you drunk or even cause terrible cramps. Don't
use nitrogen (which you've breathed all your life) because it will bubble in
your blood if pressure drops and cripple you with "bends." Use helium which
doesn't. It gives you a squeaky voice, but who cares?
You can die from oxygen shortage, be poisoned by too much oxygen, be
crippled by nitrogen, drown in or be acid-poisoned by carbon dioxide, or
dehydrate and run a killing fever. When I finished reading that manual I
didn't see how anybody could stay alive anywhere, much less in a space suit.
But a space suit was in front of me that had protected a man for
hundreds of hours in empty space.