In
this section
The
Current Spacesuit
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The Current
Spacesuit
Extravehicular
Mobility Unit (EMU), which is the current spacesuit, is used for spacewalking
from the shuttle and International Space Station. Early spacesuits were
individually tailored for each astronaut. In contrast, that the EMU has
component pieces of varying sizes that can be put together to fit any
given astronaut. The EMU has a combination of soft and hard components
to provide support, mobility and comfort. The suit itself has 13 layers
of material, including an inner cooling garment (two layers), pressure
garment (two layers), thermal micrometeroid garment (eight layers) and
outer cover (one layer).
The dimensions and facts of the EMU:
Weight - 127 kg on Earth
Thinkness - 0.48 cm, 13 layers
Atmosphere - 0.29 atm of pure oxygen
Volume - .125 to .153 m3
Maximum
Absorption Garment (MAG)
Spacewalking take long hours. During that time, their bodies produce urine.
Astronauts cannot simply go inside the spacecraft and use the toilet as
it takes too much time to pressurize and depressurize both the spacesuits
and the spacecraft. So each spacewalking astronauts wear a large , absorbant
diaper to collect urine and feces while in the spacesuit. The MAG is disposed
when the spacewalk is over.
Back
Liquid
Cooling and Ventilation Garment (LCVG)
LCVG is a set of Nylon tricot and spandex "long underwear" that is laced
with thin plastic tubes. Cool water, which comes from the spacesuit's
backpack unit or from the spacecraft through an umbilical cord, flows
through these tubes to remove the heat produced by the astronaut.
Back
EMU
Electrical Harness (EEH)
EEH is a set of communications wires and bioinstruments that is worn by
the astronaut inside the suit. It provides connections to the radio and
bioinstruments in the suit's backpack. Communication and monitoring of
the astronaut's vital signs (e.g. respiration rate, heart rate, temperature)
are allowed.
Back
Communications
Carrier Assembly (CCA)
The CCA is a fabric cap worn by the astronaut. Microphones and speakers
are contained for use with the radio. It allows hands-free radio communications
within the suit.
Back
Lower
Torso Assembly (LTA)
The LTA is a one-piece unit that contains the lower half of the EMU, including
pants, knee and ankle joints, boots and lower waist. A metal connect ring
is used in LTA to fit to the upper half of the EMU.
Back
Hard
Upper Torso (HUT)
The HUT is a hard fibreglass shell in the shape of a vest. It supports
several structures including the arms, lower torso, helmet, life-support
backpack and control module. A mini-tool carrier can also be held. Pieces
click into the HUT through quick-connect rings.
Back
Arms
Arms unit contain shoulder, upper arm and elbow joint bearings so that
the astronaut can move his or her arms in many directions. Quick connect
rings are used tho fit arms unit into the HUT. The arm units come in various
sizes so that the EMU can be fitted to different astronauts.
Back
Gloves
Gloves have wrist bearings to ease the movement. Quickconnect rings are
fitted into the arms. The gloves have rubberized fingertips to help astronauts
grip things. Astronauts also wear fine-fabric gloves inside the outer
glove unit for comfort.
Back
Helmet
The helmet is made of clear, impact-resistant, polycarbonate plastic,
and fits to the HUT by a quick-connect ring. The helmet is padded in the
rear for comfort, because the helmet remains fixed rather than rotating
with the astronaut's head. It has a purge valve to remove carbon dioxide
if the backup oxygen supply must be used. In the helmet, oxygen flows
from behind the astronaut's head, over the head and down the face. The
inside of the helmet is treated with an anti-fog compound prior to the
spacewalk.
Back
Extravehicular
Visor Assembly (EVA)
The EVA fits over the helmet. It consist of the following main pieces:
- A metallic-gold-covered visor to filter sunlight
- A clear, impact resistant cover for thermal and impact protection
- Adjustable blinders to block sunlight
- Four head lamps
- A TV camera
Back
In-suit
Drink Bag (IDB)
Astronauts working in a spacecraft need water. So the spacesuit has the
IDB, which is a plastic pouch mounted inside the HUT. The IDB can hold
1.9 liters of water and has a small tube, a straw, that is positioned
next to the astronaut's mouth. There is also a slot in the helmet for
a rice-paper-covered fruit and cereal bar that the astronaut can eat if
he or she gets hungry during the spacewalk.
Back
Primary
Life-Support Subsystem (PLSS)
The PLSS is the backpack worn by the astronaut. It contains the oxygen
tanks (0.54 kg at 518 atm tank pressure), carbon dioxide scrubbers/filters,
cooling water (4.6 kg), radio, electrical power, ventilating fans and
warning systems. Oxygen flows into the suit behind the astronauts' head
and out of the suit at the feet and elbows. Once inside the PLSS, the
air flow enters a charcoal cartridge, to remove odors, and then the carbon
dioxide scrubber cartridage. The gas flow through a fan, and then to a
sublimator that removes water vapour and returns it to the cooling-water
supply. The temperature of the air flow is maintained at 12.8 degrees
Celsius. The temperature, pressure and air flow can be adjusted through
controls on the DCM. The PLSS provides up to seven hours of oxygen supply
and carbon dioxide removal.
Back
Secondary
Oxygen Pack (SOP)
The SOP is an emergency oxygen supply, it has two oxygen tanks that contain
a total of 1.2 kg at 408 atm tank pressure. The oxygen supply turns on
automatically once the oxygen pressure in the suit drops below 0.23 atm.
This is enough oxygen for 30 minutes, which is sufficient time to get
a crewmember back inside the spacecraft.
Back
Display
and Control Mdule (DCM)
The DCM is mounted on the chest, it contains all of the switches, gauges,
valves and LCD display necessary to operate the PLSS. The DCM can be seen
by astronaut, sometimes with the aid of a sleeve-mounted mirror.
Back
Servicing
and Cooling Umbilical (SCU)
The SCU is an umbilical cord containing tubes for cooling water, electrical
wires for power and tubes for oxygen. The SCU is used to provide water,
power and oxygen to the EMU while the astronaut is in the airlock preparing
for the spacewalk. This helps conserve the EMU's expendable supplies until
the astronaut actually leaves the spacecraft.
Back
Airlock
Adapter Plate (AAP)
The AAP is a frame mounted to the wall of the airlock that helps hold
the EMU pieces while the astronaut is suiting up.
Back
Helmet
Lights and Caemra
These devices are mounted on the EVA, which fits over the helmet. It aims
at helping the astronauts and ground controllers see into dark areas.
Back
Sleeve-mounted
Mirrors and Checklists
These devices fit over the sleeves of the EMU. The mirrors help the astronauts
see the DCM displays and see behind them. The checklists help them remember
procedures over the course of a spacewalk.
Back
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Graphic:
Photo Courtesy
NASA
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