Updated: Nov 22, 2021
As you move away from the center of the Earth and out of the atmosphere, the possibility of encountering and being damaged by many external factors such as extreme temperature changes, high vacuum, microgravity, plasma, harmful cosmic rays, flying objects, micro-macrometeroids increases. As a result of the synergistic interaction of one or more of these factors, irreversible changes such as abrasion, mass loss, structural modification, and degradation may occur in the materials. For this reason, in order for living or non-living beings to be able to engage in any activity or function in space, they must adapt to space conditions and be protected from these harmful effects.
The special suit worn by an astronaut in space is as important as the rocket and capsule that take her to space.
Astronauts wear different clothes according to their environment and mission. An astronaut who is responsible for technical work in the space shuttle prefers technical clothing that provides maximum benefit to him during maintenance and that contains many pockets and Velcro that can easily carry the equipment he uses. During the landing and take-off of the space shuttle, they wear pressure-adjustable clothes called LES (Launch and Entry Suits). Astronauts working outside of the space shuttle or in space wear one of the most expensive and technical clothing in the world, consisting of many components called EMU (Extravehicular Mobility Unit), which is quite different from other suits. EMU has a modular structure with interchangeable parts. It basically consists of upper body, lower body, arms, helmet and gloves. The parts are separate and integrated appropriately for each body. In this way, it provides advantages in terms of reusability and cost.
EMU consists of different layers and components. The main function of each layer and component is to ensure that astronauts are not affected by the harsh conditions in space. The basic functions that the EMU should provide are;
low internal pressure,
High tensile strength,
Protection against ultraviolet radiation,
Protection against particulate radiation,
Protection against small micrometeroids,
Storage of physiological waste.
A spacesuit also protects the astronaut from the extreme heat of space. The temperature in space is not constant everywhere. In this case, the suit's life support system must transfer the heat and moisture produced by the working and sweating astronaut. This is usually achieved by circulating cold water in an inner suit that is placed on the astronaut's skin.
The EMU consists of thirteen layers; inner cooling suit (two layers), pressure suit (two layers), thermal micrometeroid suit (eight layers), and outer cover (one layer). In these layers, durable materials such as nylon tricot, spandex, urethane-coated nylon, dacron, neoprene-coated nylon, mylar, gortex, kevlar, nomex are used.
TMG - Thermal Micrometeoroid Garment
The thermal micrometeroid suit (TMG) is the outer layer of the space suit. TMG has three functions; insulation, protect from harmful solar radiation and micrometeroids.
TMG starts with a layer of neoprene coated nylon ripstop. Next, five layers of aluminum-coated Mylar for thermal radiation shielding; followed by four layers of nonwoven Dacron creating thermal gaps, followed by two layers of aluminum coated Kapton film and Beta fabric. The outermost layer of Teflon-coated Beta fabric is non-combustible and shows high resistance to moon dust, known as abrasive. This layer is supported by Teflon patches at the knees and elsewhere. The outermost layer is white Ortho fabric, made with a combination of Goretex, Kevlar and Nomex.
LCVG - Liquid Cooling and Ventilation Garment
Mobility during spacewalks increases the body heat produced by the astronaut. Space is completely empty, heat cannot be lost by conduction and can only be dissipated by thermal radiation, which is a much slower process. Thus, even if space is very cold, excessive temperature rise is not possible. The cooling and ventilation garment is like a full-body undergarment and its purpose is to maintain a stable body temperature in non-shuttle activities. The cold water circulating through the flexible tubes takes the body's heat and prevents the temperature from increasing excessively, allowing the astronaut to work more comfortably.
Used in NASA's non-shuttle mobility unit, the LCVG was originally made with a nylon tricot and spandex. The tubes in which the water is carried are polyvinyl chloride.
CCA- Communications Carrier Assembly
The CCA is a fabric beret worn by the astronaut. It includes microphones and speakers for communication. It enables hands-free radio communication in the garment.
LTA - Lower Torso Assembly
The lower body is a one-piece unit and contains the lower half of the EMU, these are the pants, knees, ankles, boots and lower waist. It is joined to the upper part of the EMU by a metal coupling ring.
HUT- Hard Upper Torso
The upper body is a vest-shaped shell made of hard fiberglass material. Supports many structures including arms, lower body, helmet, life support bag and control module. It can also hold a mini tool carrier. The parts are connected to the upper body with rings.
MAG- Maximum Absorption Garment
Spacewalking astronauts can spacewalk for approximately seven hours. During this time, their bodies produce urine, but it takes so much time to pressurize and depressurize both the spacesuits and the airlocks and the spaceship that the astronauts cannot get inside the ship and use the toilet. That's why every walking astronaut wears a large, absorbent diaper inside his suit to collect urine and feces.
Arm units include shoulder, upper arm, and elbow joint rotations so that the astronaut can move his arms in many directions. Arm units come in many sizes so the EMU can be used by different astronauts. The arm units are joined by connecting rings.
Legs; consists of trousers and boots assemblies. The boots are connected to the trousers with the boot fastenings, the trouser vest twist to the vest assembly and the vest assembly to the body closure.
Gloves should form a protective barrier against the natural environment and workplace hazards. Each glove consists of three different structures: inner rubber, protective outer layer and heat-balancing intermediate layer. Fingertips and palms of the gloves are also covered with rubber. In this way, both insulation and protection are provided and the equipment used is prevented from slipping. Gloves are mounted on the arms. Astronauts also wear thin fabric gloves inside the outer gloves for added comfort. The outer gloves have loops on them for attaching tools.
Fingertips contain four different materials. RTV 157 is an outer coating used for abrasion resistance. Nomex fabric is a very strong and durable fabric and is attached to RTV. Nomex felt is used for both thermal protection and peel protection. Finally, the finger cap RTV 630 was used to increase the astronaut's fingertips, tactile sensation, and protection.
The front of the fingers is covered with RTV 157 to increase grip and touch and to provide thermal durability. Nomex fabric is also used because of its superior adhesion and wear properties.
The helmet is made of transparent, impact resistant polycarbonate material, it is connected to the upper body with the attachment ring. The helmet stays fixed instead of moving with the astronaut's head, so there are pads on the back of the helmet that provide comfort.
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