outer restraining fabric suit. Second, 
just like an inflated balloon, a pressur- 
ized spacesuit is forced by the pressure 
of the gas within it into an inflated and 
stiffened position. When an astronaut 
moves in a suit in that condition, the gas 
inside the suit is slightly compressed, 
but the energy to compress the gas is 
supplied by the astronaut. 
A spacesuit easier to move around in 
Nylon mesh garment worn under 
modern spacesuits is equipped with 
soft plastic tubes that carry cooling 
water. Below, a model already wearing 
the lower section of a suit crouches 
to get into the upper section. 
and a portable life-support system that 
would allow the astronauts to be inde- 
pendent of their space capsules were 
clearly needed for the Apollo moon 
landing program of the late 1 960s. The 
purpose of the Apollo mission was to 
explore the lunar surface, set up and 
perform a variety of scientific experi- 
ments, make geologic observations, and 
collect lunar samples. The Apollo space- 
suits had to shield the astronauts from 
the hazards of the lunar environment 
and provide the necessary life-support 
systems for periods of up to eight hours 
during which the astronauts would be 
walking on the moon. 
Most people have seen pictures of 
white-suited astronauts on the lunar sur- 
face. Very few people, however, have 
ever seen an actual Apollo spacesuit. 
The familiar white suit is only an insu- 
lated outside cover made of canvaslike 
material, worn over multiple layers of 
thin plastic film coated with an alumi- 
num spray. The surface of the moon can 
get as hot as 250° to 300 °F where it is 
exposed to the sun. The shaded areas, on 
the other hand, can get as cold as 
—250°. Because the moon has almost no 
atmosphere to filter out incoming solar 
radiation, the astronaut is also baked by 
direct rays from the sun. The white 
outer suit was designed to insulate and 
protect the astronaut from these ex- 
treme temperatures, but unfortunately, 
at the same time, it seals in the heat 
produced by the astronaut’s body. 
All living creatures generate heat as a 
result of the metabolic processes that 
maintain life. A resting human adult 
produces about as much heat as a 100- 
watt light bulb. When working hard, the 
same individual can easily generate ten 
times as much heat energy. The human 
body has built-in temperature regula- 
tion systems that maintain safe body 
temperatures of about 91° to 102° dur- 
ing normal activities on the earth. Skin 
temperature is controlled by blood flow 
to the skin and sweat rate. Body heat is 
carried away primarily by the circula- 
tion of the air around us and by the 
evaporation of sweat. But an astronaut 
enclosed in a pressure suit and an insu- 
lated protective suit must be cooled by 
other means. 
Relatively little attention was given to 
cooling during the Mercury and Gemini 
programs. The Gemini suit incorporated 
a system of ventilation ducts that was 
intended to cool the astronauts by blow- 
ing oxygen from the capsule over their 
bodies. Experience showed that this sys- 
tem was inadequate to cool someone 
who was working hard while wearing a 
pressure suit. Therefore a liquid-water 
cooling system was developed for the 
Apollo program. The Apollo astronauts 
wore a liquid cooling garment (LCG) 
under their spacesuits and next to their 
skin. The LCG looks like a suit of long 
underwear with a network of fine, flexi- 
ble tubing attached to it. Body heat was 
removed by cool water pumped through 
the tubes. In addition, the Apollo suits 
had urine containment and transfer sys- 
tems, and the astronauts wore a diaper- 
like garment under the LCG, just in 
case. These cooling and elimination 
processes were found effective and they 
are still in use in the suits designed for 
the space shuttle. 
A backpack first introduced in the 
Apollo program was a key protective 
element. All of the life-support systems 
carried by the astronaut were in this 
Anthony Wolff 
55 
