1034
FLIGHT International,
Space/light
THE APOLLO SPACESUIT
The astronauts' spacesuit for the US lunar landing mission is the
only operational equipment which must be designed to go all the
way to the surface of the Moon and return to Earth. The Apollo
suit, now being developed by crew systems division of the Manned
Spacecraft Center, Houston, for use on the lunar surface is not a
single garment, but an integrated series of garments. It is designed,
the Houston centre states, to provide the astronaut with the best
possible protection against the environment he will encounter on the
lunar surface.
The suit, inevitably, is known not as a spacesuit but as an
extra-vehicular mobility unit. It must shield its occupant against
extremes of temperature from — 250°F to +250°F. Micrometeoroids and the complete vacuum of space are two other hazards
which it must withstand.
The well-dressed astronaut will wear the following assembly when
he steps on to the lunar suface. The first-layer is a liquid-cooled
undergarment. The best method of cooling the astronaut,' it has
been established, is by circulating cool water through small tubes
which are in direct contact with the skin.
The second layer of the astronaut's attire is the pressure-garment
or the actual suit assembly. This must be pressurized while the
astronaut is on the lunar surface to protect him against vacuum.
The soft pressure-garment tends to take a spherical shape when
pressurized, so joints must be built into the suit to provide
mobility.
The astronaut's spacesuit developed for
NASA's Apollo programme and described
on this page, worn
here by a Hamilton
Standard engineer,
over whose right
shoulder can be seen
the portable lifesupport back-pack
24 June I9(,S
Mobility can vary in different joints of the suit, and engineers
must design each suit joint to give the greatest mobility for its
corresponding human joint. For example, a knee-joint needs only
a flexure or bending movement. It would not be acceptable as a
shoulder-joint, which must make many complex motions.
Covering the pressure suit is a micrometeoroid protection garment
This is composed of lightweight materials arranged to provide as
much protection from meteoroids as a thin sheet of aluminium.
The astronaut's attire is completed with a thermal overgarment
composed of many thin layers of super insulation with a white
synthetic fabric as an outer layer. Thermal mittens protect the
hands and are provided with slit openings in the palms to enable
specially insulated gloves to be used when tasks requiring finger
dexterity must be performed..
The suit, including the thermal and micrometeoroid garment,
weighs less than 501b. The backpack which supplies oxygen and
ventilation to the astronaut on the lunar surface weighs 601b, and
emergency oxygen and communications weigh 101b.
While wearing all this equipment, the astronaut must be able to
walk over the surface and perform many tasks. The suit unit was
taken to Bend, Oregon, recently to be tested in terrain similar to
conditions expected to be found on the Moon. The tests indicated
that some joint areas, particularly in the thigh and ankle, need
improvement to allow the man to move and perform assigned tasks
more easily.
Engineers at Houston are further developing the suit to reduce
the weight and bulk of the outer layers to provide more mobility,
and several alternate approaches have been suggested. In one
concept, micrometeoroid and thermal protection would be integrated as additional layers to the basic Apollo suit, as the Gemini
extra-vehicular suit is constructed. A second approach combines
the two types of protection into the basic suit below the waist, and
the astronaut would wear a separate covering on the upper part of
the body.
Protection for the astronaut's eyes must also be considered as
part of the pressure-garment assembly. Without any atmosphere
to scatter and cut down the power of the Sun's rays on the lunar
surface, the astronaut will be exposed to visible, infra-red, and ultraviolet rays. Solar reflection from the space suit, the lunar excursion
module, or scientific equipment may produce a blinding glare.
Dark adaption problems will be created by the transition from light
to shadow in sunlit areas.
As a solution to these visual problems, an adjustable visor has
been designed to fit on the helmet. This can reflect 80-90 per cent
of visible light, 60-80 per cent of infra-red rays, and nearly all of the
ultra-violet rays. An inner and outer visor arrangement prevents
fogging caused by temperature extremes.
While the Apollo suit is undergoing its development, the Gemini
suit has been qualified for early Earth-orbital flights. With small
modifications, Gemini suits will also be used for early Apollo
Earth-orbital missions to allow design engineers to concentrate on
developing the Apollo suit for lunar trips.
For micrometeoroid protection, a cloth material which will stop
penetrating particles has been developed for Gemini. The Gemini
suit has been qualified for vacuum and extreme temperature operation in the 35ft diameter vacuum chamber at the Manned Spacecraft
Center.
Since the beginning of the US manned spaceflight programme
the development work in suits has had two goals. First, to protect
the man inside the spacecraft cabin in case of a loss of pressure.
Second, to provide protection for the man venturing outside into
space. The investment in developing pressure suits for Gemini and
Apollo has already reached $12m.
Test equipment for UK-3 and other Earth satellites has been
ordered for the Royal Aircraft Establishment from the M.E.L.
Equipment Company Ltd. This follows a design study by M.E.L.
for a data-sensing and extracting system for a satellite environmental
testing facility. The work is largely connected with temperature
sensors and ancillaries for operation between —180° and + 180 C
in the RAE's new full-scale environmental chamber. The satellite
under test can be moved in two directions at right angles to each
other in the chamber and rotated continuously for three turns about
its own axis. Considerable attention has therefore been given to
devising a flexible joint for connecting a large number of sensors
on the satellite to the external equipment.