Spacesuits aremuch more than a set of clothes astronauts wear. However, like a set of clothes, different suits serve different purposes. Space exploration usually includes two different kinds of spacesuits, both of which protect astronauts from the dangers of their mission. One kind is worn inside a spacecraft during launch and ascent to space, and again on the way home during re-entry into Earth’s atmosphere as well as during landing. The other kind, described here, is designed specifically for spacewalks.NASA calls a spacewalk an Extra-Vehicular Activity, or EVA, so this type of suit is often called an EVA suit.
A fully equipped spacesuit used during spacewalks isactuallya miniaturespaceship shaped like a human bodythatprotects the astronaut from the dangers of being outside a vehicle while in spaceor on the Moon.Spacewalking astronauts faceradiation, dust, debris, and extreme temperatures.Temperatureson spacewalks mayvaryfromas cold asminus 250 degrees Fahrenheittoas hot as 250 degreesin the sunlight.The suitsprovide theproperpressure for the body andsupply astronauts withwater to drinkandoxygen to breathe.
The spacesuit worn for spacewalks outsidethe International Space Stationis called the extravehicular mobility unit, or EMU. NASA is currently developing anewsuitthat will be worn for spacewalks on Artemis missions called the Exploration Extravehicular Mobility Unit, orxEMU.Itincludes severalnewfeatures and technological advances, butthesuitsshare most of the same basic elementsthat work together to keep crew members safe and healthywhile allowing them to accomplish their tasks whenworking outside their spacecraftin harsh space environments.
The two main parts of a spacewalk spacesuit are the pressure garment and the life support system. The pressure garment is the human shaped portion of the spacesuit that protects the body and enables mobility. The primary components of the pressure garment are the cooling garment, upper torso, lower torso and helmet.
Cooling Garment
The first piece of a spacesuit that astronauts put on isa special cooling garment made ofastretchy spandex materialandwater tubes.About300feetoftubes are woven into this tight-fitting piece of clothing that covers the entire body exceptfor the head, hands and feet. Chilledwater flows throughthetubesnear the spacewalker’s skinto regulate body temperature andremove extra heatduring the spacewalk, which typically lasts multiple hours.Vents in the garment draw sweataway from the astronaut’s bodyandhelp with circulation inside the spacesuit garment.
Hard Upper Torso
Thehard upper torso is lightweight but strong andconnects the inside of the suit with the appropriate systems in the portable life support system.It is shaped like a sleeveless shirt and connects to the arm assemblythatcovers the arms andjoinsthe gloves.The upper torso of the new exploration suits will have a rear-entry hatch to allow astronauts to climb into the back of the suit.
Gloves
Astronauts must be able to work with and pick up objects while wearing spacesuit gloves.Glovesprotect astronauts from the space environment andare made so spacewalkers can move their fingers as easily as possible. The fingers are the part of the body that gets coldest in space,and the gloves on spacesuitsare equipped withheatersto keepfingerswarmwhile still allowing dexterityto use tools.
Lower Torso
The lowersectionof the suitis made up of spacesuit pants, boots and the lower half of the waist closure. A piece called the waist bearing helps the astronaut move and turn. A metal body-seal closure connects the lower torso to the hard upper torso.On the new suits that will be used for lunar surface missions, the lower torso includes advanced materials and joint interfaces that allow bending and rotating at the hips, bending at the knees, and hiking-style boots.With this new mobility, astronauts will be able to walk on the lunar surface, instead of doing the “bunny-hop” developed byApollo moonwalkers.
Layers
The flexible parts of the suit are made fromas many as 16layers of material. The layers perform different functions, from keeping oxygen within the spacesuit to protecting from space dust.Closest to the astronaut’s skin, thecooling garment makes up the first three layers. On top of this garment isthe bladder layerthat is filled with gas tocreateproper pressure for the bodyandholds in the oxygen for breathing. The next layer holds the bladder layer to the correct shape around the astronaut’s body. The ripstop liner isatear-resistant layer. The nextseverallayers are insulation and act like a thermostohelpmaintainthe temperature insidethe suit. Thewhite outer layer reflects heat from the sunlightandis made of a fabricthat blends three kinds of threads. One thread provides water resistance, another is the material used to make bullet-proof vests, and the third component is fire-resistant.Some suits are plain white andsome havestripestohelptell one spacewalker from another.
Life Support System
On the back of the spacesuit is abackpackthat houses the supplies and equipment to make the suit work. This backpackcontains the oxygen that astronauts breathe and that pressurizes the suit. A regulator in the backpack keeps the suit at the correct pressure. A fan circulates oxygen through the suit and life support system wherethecarbondioxide that astronauts exhale is removed from the suit. The backpack provides electricity for the suitand holdsa two-way radiofor communication. The backpack also contains water for thecoolinggarment, a chiller to cool the water, and a pump that circulates the chilled water.
CommunicationsSystem
Historically,a communications cap is worn under theastronaut’s helmetthat contains earphones and microphones. The capconnects to the radio on the spacesuit and enables the astronaut to talk to other crew members and mission control. The communications cap is sometimes called the Snoopy cap for its resemblance to the aviator cap worn by the cartoon character. The new explorations suit includes an upgraded audio system inside the helmet that does not require the astronaut to wear a cap. The integrated communication system has speakers mounted inside the helmet area and multipleembeddedvoice-activated microphones that automatically pick up the astronaut’s voice.
Helmet
The helmet on spacesuits built for spacewalks serves as a pressure bubble and is made of strong plastic to keepthe pressure of the suit contained. It also has a ventilation system that provides astronauts with oxygen.Helmets also contain a small foam block that astronauts can use to scratch their noses.Outside of this bubble is a protective visor that keeps the pressure bubble from getting bumped or scratched. On top of the protective visor arethe sun visor and sun shades. The sun visor has a special gold coating that works like the astronaut’s sunglasses. Together, themovable sun visor and sun shades protect the astronaut from the sun’s strong rays, while still allowing a clear visual field.The helmet on the suits that will be worn for Artemis missions will feature a quick-swap protective visorthat protectsagainstthe abrasive dirt of planetary bodies.The helmet for these new suits also features an elliptical shape that provides a better view of the ground around the spacewalker’s feet.
