oped by Hamilton Standard, the Apollo PLSS carried oxygen, batteries,
lithium hydroxide carbon dioxide scrubbers, water cooler, fan, radio,
and emergency oxygen. Oxygen was pressurized to 3. 7 PSI and fed into
the astronaut’s helmet and suit. The first Apollo lunar missions had a
four-hour supply of oxygen and the PLSS weighed 65 pounds on Earth,
or 11 pounds on the Moon. Because of the PLSS, Apollo astronauts
kept cool in a way entirely different than the earlier Mercury and
Apollo astronauts wore the liquid cooled garment, or LCG, to
keep cool. The LCG was made of thin PVC tubing (Tygon) sewn into
a nylon spandex suit and inner layer of nylon tricot for comfort
(Klingons probably use a wool comfort layer). The water temperature
was set to 70°F and kept the astronaut cool
at various levels of exertion. Water flowing
through the LCG was chilled through a
sublimator in the PLSS.
■ APOLLO A7L SUIT
hydroxide, and 75 minutes
of emergency oxygen. The
weight of this PLSS was
212 pounds on Earth, or 35
pounds on the Moon. Modifications in the PLSS also
allowed astronauts to buddy breathe (share oxygen
from a single PLSS) should
one PLSS fail. The helmet’s
BOOTS ARE MADE
Like the spacesuit, moon boots were
made up of fabric layers for thermal, abrasion,
and micrometeorite protection. The boots
looked a lot like oversized rain boots.
The soles of the boots were made from molded silicon rubber for insulation, flexibility, and
GLOVES AND HELMET
The gloves of the Apollo EMU were more
flexible than those in the Gemini spacesuit. To
add a sense of touch to the gloves, silicon
rubber pads were sewn into the fingertips.
The outer layer of the gloves consisted of a
layer of Chromel-R for high temperature
resistance. The gloves were not perfect,
however. The astronauts had to cut their fingernails short and exercise their hands while
training for their mission. Apollo astronauts
still experienced painful fingertips after working on the Moon.
For increased visibility, the Gemini
helmet and visor were replaced with a
single-piece clear bubble helmet of poly-carbonate plastic. A fabric hood went over
the early Apollo helmets to block sunlight
from shining into the helmet. In addition to
increasing visibility, the single piece helmet
also increased the A7L’s reliability by
removing the airtight seal needed in the
Gemini helmet visor. The outside of the
helmet had two visors that could be
lowered, similar to sunglasses.
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The later, long duration missions used
a modified PLSS that held seven hours of
oxygen, more cooling water, more lithium
November 2005 NUTS & VOLTS 73