equipment (PPE), also known as an
extra-vehicular activity (EVA) suit or
extra-vehicular mobility unit (EMU) (www.
is.gd/qobehu). Astronauts that partake
in a spacewalk face many dangers, from
dust and debris, to radiation, extreme
temperatures (ranging from -155°C to
121°C) and lack of oxygen – so these
suits provide a means of survival when
venturing ‘outside’. They are, in essence,
miniature spaceships.
Before we get into the details, it is
important to note that the spacewalk suit
is not worn in the spacecraft on the way
up to, or down from, space. The suit for
launch, ascent, re-entry and landing is not
covered here.
The spacewalk suit has two main parts:
the pressure garment, which consists of
various components (detailed below) and
the life support system. The former is
the human-shaped portion of the space
suit that so many would have seen from
photographs and videos over the years. It
e ectively protects the body and enables
mobility.
The most inner part of the pressure
garment is a cooling garment that covers
the entire body except for the head,
hands and feet. It is made of a stretchy
spandex material with around 300 feet
of woven-in water tubes. Within these
tubes ows chilled water to regulate
body temperature and remove extra
heat during the spacewalk. Vents in the
garment also draw sweat away and help
PPE – IN SPACE
character – as well as earphones and
microphones. These components
connect to a radio on the suit and enable
the astronaut to communicate with
mission control and crew members.
Changes to the design are also being
introduced with the next generation
spacesuit for the Artemis generation of
astronauts (see box, next page).
The helmet serves as a pressure
bubble and is made of an impact-resistant
ISS statistics
The ISS orbits Earth at an average
altitude of approximately 250 miles
The ISS travels at 17,500 mph and
orbits Earth every 90 minutes
The ISS covers the area of an
American football eld
The ISS has the volume of a vebedroom
house or two Boeing 747
jetliners
The ISS can support a crew of six
people, plus visitors.
Source: NASA (www.is.gd/winufo)
with air circulation.
The hard upper torso of the suit is
made of breglass and connects the
inside of the suit with the appropriate
systems in the portable life support
system (see below). It is shaped like a
sleeveless shirt and connects to the arm
assembly that covers the arms and joins
the heated gloves. As the astronauts do
not wear custom-made suits, di erent
sizes of arm assembly parts are available
with sizing rings allowing the arm parts to
be made longer or shorter.
The lower torso section, meanwhile,
consists of spacesuit trousers, boots and
the lower half of the waist closure. A metal
body-seal closure connects the lower
torso to the hard upper torso. D-rings are
also present so that tethers (cords) can be
attached to the station when conducting
a spacewalk to stop the astronauts from
oating away.
Finally, there is the headgear, which
consists of a communications system
and helmet. The communications
system features a cap – often
referred to as a ‘Snoopy’
cap because of its
resemblance to
the aviator cap
worn by the
cartoon
Autumn 2020 www.operationsengineer.org.uk 21
/winufo)
/www.operationsengineer.org.uk