Yeager, wore on flights of the Bell X-1.
The need to fly longer and higher
motivated both the Navy and Air Force to
develop a full pressure suit. Due to funding
constraints, however, development was left
to the Navy while the Air Force continued
refining the partial pressure suit.
Several full pressure suits were developed in the 1950s. The David Clark Company
developed a full pressure suit that eventually became the A/P22S-2, and B.F. Goodrich
developed five full pressure suit models (the
Mark I to the Mark V).
The A/P22S-2 consisted of a neoprene-coated nylon inner layer to retain air and outer layers of fabric to protect the airtight inner layer from abrasion and sunlight. The
oxygen mask of the partial pressure suit was
replaced with a helmet. To prevent the suit
from ballooning out when filled, the David
Clark Company added a layer resembling a
nylon fish net over the air bladder layer. The
A/P22S-2 full pressure suit was worn by pilots in the X- 15 program.
■ MERCURY PROJECT SUIT
SPACESUITS OF THE
Project Mercury was tasked with getting an American into space
and bringing him back safely. There was no plan for the astronauts to
leave the Mercury capsule so it remained airtight for the entire flight.
However, in the event of a depressurization, the astronauts needed a
spacesuit to keep them alive long enough to return to Earth. For the
Mercury spacesuit, B.F. Goodrich modified a version of the Navy’s full
pressure suit, the Mark IV.
To get into and out of the Mercury spacesuit required manipulating 13 zippers. The spacesuit maintained an atmosphere of pure
oxygen at 5 PSI of pressure, so in a vacuum, the astronauts breathed
more oxygen that we do at sea level (where the partial pressure
of oxygen is only about 3 PSI). The temperature was controlled by
adjusting the temperature of the oxygen flowing into the suit. Oxygen
entered the suit at the waist, flowed around the body, and exited out
of the helmet by the right ear. This movement of air kept the astronaut
cool and dry. Air exiting the spacesuit was passed through activated
charcoal to remove body odors and lithium hydroxide to remove
There were four layers in the Mercury
spacesuit. A rubber-coated, double-walled
nylon formed the primary pressure vessel,
a neoprene-coated layer formed an extra
protection layer, and aluminized nylon formed
the outer layer for flame and abrasion
protection. The long john underwear worn
by the astronaut was the fourth and innermost layer of the suit. Since the astronauts
remained inside the capsule for the
entire flight, there was no need for thermal
protection layers as would be needed in the
Gemini, Apollo, and the Space Shuttle.
In case of a capsule decompression,
the spacesuit rapidly filled with oxygen supplied by the Mercury capsule. The spacesuit
was very stiff when filled, but bending in the
suit was made a little easier by break lines
sewn into the spacesuit. However, the break
lines didn’t let the spacesuit maintain a
constant pressure during bending, so it still
took some effort to bend limbs. The cost for
each Mercury spacesuit was about $5,000, and half of that was just for
Modifications were made to the Mercury spacesuits throughout
the program. Alan Shepard’s spacesuit was the only one that didn’t
include a urine collector, as you may recall in the movie, The Right Stuff.
After Shepard’s flight, this vital comfort was added to the suit. Another change was the inclusion of tiny light bulbs sewn into the gloves so
astronauts could read the capsule’s panels during orbital night.
SPACESUITS OF THE
The Gemini Program flew 12 flights between Mercury and Apollo
and taught NASA how to perform extravehicular activities (EVA), dock
spacecraft, and live in space for extended periods of time.
Three types of spacesuits were designed for the Gemini program.
The first Gemini spacesuit was the G3C and was worn as an intrave-hicular suit (for astronauts who weren’t leaving the capsule for a space
walk). Like the previous Mercury spacesuits, the G3C provided air,
temperature, and humidity control through the spacecraft’s life support
system. This means the spacesuit was left plugged into the spacecraft
during the entire mission. Air flowed into the chest, through the helmet
to clear the visor, around the body, over extremities, and exited the suit.
■ MERCURY G5 SUIT
■ GEMINI G4C SUIT
■ GEMINI G3C SUITS
November 2005 NUTS & VOLTS 71