A spacesuit or a Pressure Garment Assembly is a pressurized garment which houses an astronaut. It assures the protection of astronauts from the hostile environment and damaging conditions of space. The design of spacesuit assures an atmosphere for breathing. Also, it protects from cold, heat, and other micro-meteoroids. The suit houses an astronaut during the critical phases of the mission, including when the command module is unpressurized.
Various manufacturers design the components of a spacesuit, and then National Aeronautics Space Agency assembles them all at their headquarter in Houston. In 1950, they introduced the first suit. A spacesuit costs over 10.4 billion dollars.
Spacesuit Provides Artificial Atmosphere
The spacesuit must offer an artificial atmosphere for the astronaut to survive. It has pressurization to 3.7 PSI and 100% leak-proof oxygen. Each spacesuit provides adequate mobility, micrometeorite protective system, ability to function for three hours on the moon surface, and a good visual protection system.
A spacesuit has a good insulation system installed which protects from a temperature between 250 to -250 degrees Fahrenheit. Also, spacesuits have superinsulation. It prevents the heat from leaking into the spacesuit, maintains the heat flux by 250 BTU/hr (lunar day) to 350 BTU/hr (lunar night). The calculated solar heat flux is 10 thousand BTU/hr.
The spacesuits protect astronauts from IR (Infrared), solar UV (ultraviolet), and visible light radiation. Also, it shields the astronauts from the meteoroid particles which are traveling at 64 thousand miles per hour.
History of Spacesuit
As technology has improved, the spacesuits have evolved naturally. Earlier, these suits were tailor-made as they were less complex than today’s one. On the first US suborbital, Alan Shephard wore a suit that was just a bit better than the suit of US Navy high altitude jet. This suit had a double layer. It was uncomfortable enough to move one’s hands and legs.
Then came the suits of the second generation; pressurized perfectly for the astronauts. But it didn’t allow spacewalks as it wasn’t strong enough to protect from hostile conditions of space even though it had five layers. The five layers were of cotton attached with biomedical devices, a pressurized blue nylon layer coated with neoprene, Teflon layer, and a white nylon layer. The cotton layer – attached to the biomedical devices. The blue nylon layer to provide oxygen if any disturbance occurred in the cabin pressure module. The Teflon layer gave shape to the suit when pressurized and the white nylon shielded it from sunlight by reflecting it, and protected from accidental damages.
The first spacewalk happened in 1965 during Gemini Missions. The spacesuit manufactured for that mission had seven layers. This spacesuit protected the astronauts from heat and micrometeoroids. It weighed 15 kgs. Still, these spacesuits turned out to inadequate due to some minor problems.
During the Apollo mission, some of these problems solved. They used the seven-layered spacesuit with a lifeguard backpack. It weighed 26 kg.
Over the last several decades, as the new material became available, the spacesuits have undergone several improvements except the look remains the same. The latest spacesuit has fourteen layers and weighs almost over 125 kg.
According to the items assembled in a spacesuit, two ways of configuration are available.
- Extravehicular – The extravehicular is designed for outside the spacecraft. The extra backpack with the Extravehicular spacesuit defines the EMU (Extravehicular Mobility Unit). This backpack consists of electrical power, communication, oxygen, and liquid cooling supply. It has four extra components that aren’t available in an Intravehicular spacesuit. These components are -extravehicular glove, visor, a cover, and lunar overshoe.
- Intravehicular – This spacesuit comprises of constant wear garment, faecal containment subsystem, urine collection transfer assembly, integrated thermal micrometeoroid garment, torso limb suit, pressure helmet and glove and communication carries.
Raw Materials Used
Various raw materials are used to manufacture a spacesuit. Different kinds of synthetic fibres are included in the fibre materials. Some of those polymers are Nylon tricot, spandex (an elastic wearable polymer), Dacron, urethane-coated nylon, aluminized Kevlar, Gortex, Mylar, and Nomex.
Organic fibres are also used. The upper hard torso segment is made of Fiberglass. Lithium hydroxide is used to filter water vapour and CO2 during spacewalks. The battery that powers the suit has a silver zinc blend. Polycarbonate material builds up the helmet shell. Plastic tubing is intertwined with the fabric to provide a continuous supply of cooling water through the entire suit.
Components of the Spacesuit
A spacesuit is composed by assembling several tailor-made components. Over eighty companies produce the components of the spacesuit. Some of the major components are discussed below –
1. Torso Limb Suit
Torso limb suit covers the entire body except for the head and hands. It works like an envelope for the astronaut. Torso limb suit consists of three layers which are –a comfortable inner cloth lining, a gas retention bladder, and a restraint layer. Manufacturers customize the suit as per the body of the astronauts. For cooling, breathing, and defogging, the helmet has incoming oxygen duct supply from the inner surface of this suit.
Also, connectors for oxygen, urine, and water is present in the suit; connected to the respective modules. To connect communications and biomedical equipment, an electrical harness is present to the spacecraft or the portable life support system. The torso suit also houses a pressure gauge and pressure relief valve in the right and left wrist respectively.
2. Integrated Thermal Meteoroid Garment
This is a multi-layered garment; laced to the torso limb suit. It comprises the following layers –
- – The outer and inner shell of Beta cloth
- – 7 aluminized Kapton film layers separated by 6 Beta Marquisette layers
- – One liner with 2 Neoprene-coated nylon Ripstop layer
- – One Chromel-R (woven metal) layer (knees, shoulders and hands)
The cover comes with the LM restraints, the shoulder cable disconnect, the urine transfer fitting medical injection area, and the entrance slide. Also, this suit has three pockets – one on the upper left arm, one on the upper right arm, and one on the upper right thigh. Moreover, it has strap-on pockets.
3. Extravehicular Glove
As the name suggests, this glove is for extravehicular tasks. It protects astronauts from heat. To improve the grip of the glove, they use Chromel-R coated with a silicone dispersion. This glove covers the hands entirely. This glove houses a thermal meteoroid pressure glove, protecting the thermal insulating shell. This shell is similar to the thermal meteoroid pressure glove except that it has a few additional layers of insulating material.
4. Pressure Helmet
This helmet consists of a polycarbonate transparent shell and an aluminium neck ring. The shell, connected with the aluminium ring, fits perfectly with a neck ring bounded to the torso limb suit. This helmet has a feed port and a vent pad. The feed port is available for the water and feed probes; on the left side of the helmet. This feed port is airtight. The vent pad has a recess; bonded to the back of the helmet.
5. Lunar Overshoe
Lunar overshoe is worn over the suit-boot or the thermal meteoroid garment boot. It comprises of a liner, insulation and an outer shell. The liner is of Teflon-coated Beta cloth. The 13 layers aluminized Kapton film separated by 12 Beta Marquisettes layers form the insulation. In the outer shell, there is a sole of silicone rubber; sewn with a laminated structure. This laminated structure has four layers namely – Chromel-R (outer layer of the shell) coated with Teflon Beta cloth and 2 layers of Beta Marquisette.
6. Pressure Glove
It is a gas retaining device which fits the torso limb suit. It comprises the bladder, inner and outer covers, a finger less glove, and restraint system. The bladder is a customized according to the hands of an astronaut; exposed at the inner side of the fingers. It is made of neoprene compound dipped nylon tricot. A restraint strap is attached over the palm. This strap reduces the ballooning and provides good grip control.
7. Liquid-Cooling Garment
During extravehicular activities, this garment provides cooling. It has a nylon-spandex material to support the Tygon tubing network. These tubings circulate water from the portable life support system. Chiffon composes the inner surface of the liquid cooling garment. This garment has socks too but these socks do not have the tubing network.
8. Portable Life Support System
A backpack contains this system with its components. It consists of a fibreglass shell that fits the back of the astronaut perfectly. The dimension of the portable system is 28x11x26 inches. It consists of two control switches, three control valves and a five-position switch for the transceiver of radio. The portable life support system weighs around 68 pounds.
9. Extravehicular Visor
It protects the astronaut from heat, light, and meteoroids as it fits over the pressure helmet. Also, the visor protects the pressure helmet. It comprises of a polycarbonate shell. The shell has two pivoting visors. One is for micrometeoroid protection and the other is for sun rays protection.
10. Emergency Oxygen System
As the name suggests, this consists of the oxygen module which supplies oxygen; maintains the pressure of the suit. It weighs about 2.9 pounds and is of doughnut shape. It consists of an actuating mechanism with a pressure gauge and a regulator. The storage capacity of this system is 7.2 cubic inches. The pressure of oxygen is at 7500 psi. This module is attached to the back of the left couch leg. There is a module below the containment canister for extravehicular activities.
Image Source – NASA