A spacesuit is used to ensure the survival of a person in the space environment. There are two main outfits.
The EMU (Extravehicular Mobility Unit) suit, used for maintenance in the vacuum of space, or for the exploration of the moon.
The ACES suit (Advanced Crew Escape Suit), for intra-vehicular use, to deal with potential accidental depressurization of the cabin.
How does a spacesuit work?
Space suits protect astronauts from the various dangers associated with the vacuum of space.
Indeed, outside the spaceship, humans face many dangers.
The suits consist of a helmet with a transparent plastic pressurized bubble allowing the crew members to breathe in space. It is designed to withstand impacts, in the event that micro-debris strikes the astronauts on a spacewalk.
As extra-vehicular outings can last several hours, the suits are equipped with a tube to hydrate the astronauts and a CO2 and mist evacuation system.
A camera and lights are attached to the side of the helmet, allowing teams on land to communicate and monitor mission progress in real time.
In their backs is a bag containing water reserves to regulate their body temperature (a cooling system by circulating water in small tubes incorporated into the LCVG underwear). Indeed, in space, temperatures are extreme, from 120°C in the sun to -160°C in the shade.
As the space does not contain a breathable atmosphere, the suits carry oxygen reserves to enable them to breathe, and electricity reserves to power the assembly.
On average, the on-board batteries can power the whole thing for about 6 hours.
Why are spacesuits white?
One could wonder why the combinations are not in the colors of the nations.
There are two main colors for wetsuits.
The orange suits, reserved for journeys from earth to space, and vice versa.
The orange color makes it easy to identify if a technical problem forces the astronauts to leave their capsule.
The color white is used for spacewalks, white being the color that best reflects harmful radiation from the sun, and therefore, heat.
The design of a spacesuit
For the example, we are going to talk about the space suits used for the Apollo missions, the A7L.
Indeed, many combinations have been developed, and continue to be.
Spacesuits include two garments.
The body undergarment:
This underwear is made of elastane, stretch fiber. It is traversed by 91.5 meters of narrow tubes, in which water circulates to regulate the temperature.
A system of vents draws in sweat, which the cooling system recycles.
At the same time, the astronauts are equipped with maximum absorption clothing (MAG). They are, so to speak, diapers for adults.
As spacewalks can last up to 8 hours, it would be too complex to return to the space station or spacecraft to use a toilet for natural needs.
The EMU suit:
The A7L spacesuits of the Apollo program were custom-built by the American companies ILC Dover and Hamilton Sundstrand and used between 1968 and 1975. They weigh 72 kg, but the lunar attraction being five times weaker than Earth's gravity, the astronauts had to the impression of carrying barely 14 kg.
The suits consist of 14 layers:
(1-3) The body undergarment (detailed above) constitutes the first three layers.
(4) Above this garment is the bladder layer. This creates the proper pressure for the body. It also contains oxygen for respiration.
It is made of nylon and coated with urethane (a synthetic rubber)
(5) The next layer keeps the bladder layer in the correct shape around the astronaut's body. It is made of Dacron (the same material as camping tents).
(6) The ripstop liner is the tear resistant layer.
(7-13) The next seven layers are insulating Mylar and make the suit act like a thermos. The layers prevent the temperature from changing inside. They also protect the astronaut from damage caused by small, high-speed objects flying through space.
(14) The outer layer is made of a blend of three fabrics. Two waterproof fabrics, and one KEVLAR fabric (the material used to make bulletproof vests.)
The future of space suits.
Currently, NASA is working on future spacesuits.
On the same basis as the EMUs, the xEMU (Exploration Extravehicular Mobility Unit) will be more flexible, in particular thanks to joints at the knees and hips.
They will also be more resistant to lunar dust, which infiltrated everywhere during the Apollo missions.
NASA aims to provide a wide range of sizes, in fact the current outfits were not suitable for all sizes, specifically women.
The colors of the latter are subject to change, these combinations are only prototypes to be presented to the public.