Space Suits are not just garments worn by astronauts on their journey to space; it’s more like an individual spacecraft. These are fully equipped with all the essential elements that are crucial to creating an environment which protects the astronauts from the extreme conditions of outer space. The astronauts are required to wear space suits while working in earth orbit, moon surface or anywhere else in space. These can be broadly categorised as IVA (Intravehicular activity), EVA (Extravehicular activity) and IEVA (Intra/extra vehicular activity); depending upon the purpose that they serve.
Figure 1: Space Suits
Space is devoid of a lot of important elements like oxygen and contains various harmful radiations with temperatures ranging from 120 degrees C to -100 degrees C. In order to tackle this, a space suit is designed with systems that provide an appropriate amount of air pressure, oxygen and removes the carbon dioxide as well. Besides, it also offers protection against radiation and micrometeoroids moving at high speeds in the space. Not only this, but a space suit should also provide comfort and mobility so that the astronauts can move around with ease and communicate with each other.
Working of Space Suits
As mentioned above, a space suit is more like a spacecraft and hence it is equipped with various facilities that enable astronauts to explore the space as freely as one can survive on earth. In order to provide an earth-like environment, space suits perform the following functions.
As the space carries very little or no air pressure it could lead to our body fluids getting boiled. Thankfully, a space suit provides an appropriate amount of pressure (usually 0.29 atm) so that the body fluids remain in a liquid state. It works like an inflated balloon, restricted by Neoprene coated fibers.
Owing to the low atmospheric pressure, the regular air (containing 78% nitrogen, 21% oxygen and 1% other gases) cannot be utilised by a space suit as it would lower down the oxygen concentrations in the body. As a result, it gets pure oxygen either from the spacecraft through an umbilical cord or through a life support backpack.
Carbon Dioxide Removal
The air that we breathe out contains carbon dioxide which needs to be removed from the confined area of a space suit. To serve this purpose, it contains lithium hydroxide canisters located in the spacecraft or in the space suit’s life support system.
Coping with Extreme Temperature
In order to handle the extreme temperature of space, the space suits are insulated with numerous fabric layers and covered with reflective outer layers. These are also equipped with fans or heat exchangers to blow cool air or make use of water-cooled garments. If the excess of heat is not removed, the sweat produced by the body turn into vapour and fogs up the helmet thereby dehydrating the astronaut.
Protection from harmful Radiation
Space suits are equipped with reflective coatings of Mylar that offer limited protection against radiation. However, it doesn’t guard against the solar flare, which is why spacewalks are only carried out during low solar activity.
The backpacks worn by astronauts contain transmitters and receivers while the headsets are equipped with microphone and earphones. This helps them to communicate with the ground controllers or other fellow astronauts.
Providing Clear Sight
The helmets of astronauts are made of durable plastic or polycarbonate and also fitted with tinted visors to reduce glare. The latest suits even carry lights that enable them to look into the shadows.
Often there are several micrometeoroids traveling through space at high speeds and hence there is a danger of collision. To cope with this, the space suits are equipped with multiple layers of durable fabrics like Dacron or Kevlar. These also prevent the suit from being torn when exposed to the external atmosphere of other planets or moon.
In order to allow the astronauts to move freely while wearing the suit, it is designed with special joints and tapers which facilitates in bending the body joints as required. For ensuring mobility inside the spacecraft, it contains footholds and hand restraints so that the astronauts can move from one place to another without being flown away in the weightless surroundings.
Besides, NASA has even developed some rocket maneuvering devices with the help of which astronauts can move freely anywhere without being bound to the spacecraft. Examples of such devices are Manned Maneuvering Unit (MMU) and Simplified Aid for Extravehicular Activity Rescue (SAFER). The former is a gas-thrusted powered chair with a joystick while the latter is a nitrogen-propelled device fitted on the backpack.
The history of full-pressure suits is as old as the 1930s. It all started with engineering pressurized flight suits that were meant to be used by aircraft pilots. However, the first space suit born by a human was the Soviet SK-1, which was used by Yuri Gagarin in the year 1961. Given below is the timeline representing the evolution of spacesuit technology.
Figure 2: An aircraft crew wearing Flight Suits
When the aircraft were developed, pilots needed a solution to handle the low atmospheric pressure and lack of oxygen at high altitudes much like a mountaineer. However, the suits were designed in case of failure of the pressurized cabin. These suits were made of neoprene rubber-coated fabric that could inflate like a balloon. Besides, there was also a rigid fabric that restrained the suit and directed the pressure inwards on the pilot. There were hoses connecting the suits to the plane supplying oxygen.
Figure 3: Crew of NASA’s Mercury Space Program
When NASA’s first human spaceflight program named Mercury started in 1958, they retained the basic design of the flight suits and added a few layers of aluminized Mylar over the neoprene rubber. Other than that, the uniform also included a helmet attached through a collar ring along with laced boots and a pair of gloves. The hoses connecting the suit with the spacecraft supplied oxygen while the astronauts had to carry an external fan to remove the excess of heat.
Figure 4: Astronauts of NASA’s Gemini Space Program
Since the Mercury suit was not designed to be used for spacewalking, the astronauts needed something more advanced. Then NASA came up with the Gemini Program to design suits that could be used for spacewalking and not merely in case of the cabin pressure failure.
This suit carried a human-shaped bladder made of neoprene rubber constrained by netting. It also had layers of Teflon-coated nylon to provide protection against micrometeoroids. Besides, the air cooling and oxygen were supplied through an umbilical cord.
Figure 5: Astronauts wearing Space Suits in Apollo
Soon astronauts realized the air cooling mechanism equipped in the Gemini Suits did not work well. Moreover, they got exhausted from spacewalking which led to the sweat getting vapourised thereby fogging up their helmets. As a result, some add-ons were implemented so as to design which could be used for spacewalk as well as for flying in space. It was a multi-layered pressure suit containing five layers of aluminized Mylar, two layers of Kapton, and some Teflon-coated cloth. Besides, it was accompanied by a water-cooled nylon undergarment, boots, gloves, a cap for communication and a plastic helmet.
In order to walk on the moon, the suit was combined with overboots, gloves with rubber fingertips, visors over the helmet, and a life support backpack taking care of supplying oxygen, cooling water, and removing carbon dioxide. It was weighed to be 180 lb on earth which was 30 lb on the moon.
Occurrence of Challenger Disaster
Figure 6: Astronauts of NASA Space Shuttle Orbiter Challenger
Earlier, astronauts were given brown suits to be worn in case of an emergency like the failure of cabin pressure. Later, when the shuttle flights became routine, they stopped wearing it during lift-offs. They started wearing light blue coveralls accompanied by black boots and an impact resistant plastic helmet facilitating communication.
In 1986, NASA Space Shuttle Orbiter Challenger disintegrated 73 seconds into the flight, popularly known as Challenger Disaster. It led to the death of its 7 crew members, including 5 NASA astronauts and 2 Payload Specialists. After reviewing the situation, NASA made it mandatory for all the astronauts to wear pressurized suits during lift-off and re-entry. These suits were equipped with helmet, boots, gloves, communication cap, parachute, and an inflatable life preserver.
Extravehicular Mobility Unit
Figure 7: Extra-Vehicular Mobility Unit Components
As the advancement in space exploration led to more and more space traveling and spacewalks, the soft fabrics were combined with hard components to enhance the support, mobility, and comfort for space travelers. This suit was introduced in 1981 but now holds a lot of amendments and alterations. Today it’s one of the two suits that are used worn at the International Space Station (ISS).
It contains 13 layers, including eight layers of thermal micrometeoroid garment, two layers of the inner cooling garment, two layers of pressure garment and an outer cover. It makes use of materials like Nylon Tricot, Spandex, Urethane-coated Nylon, Dacron, Kevlar, Nomex, etc. Earlier, each astronaut got an individually tailored suit but now it’s designed with varying sizes so that it could fit any astronaut.
An EMU has the following basic components
• Maximum Absorption Garment
It may take up to seven hours to complete a spacewalk and a lot of time is consumed to pressurize and depressurize the suit as well as the airlock. So, one can’t simply move in and out of the spacecraft just for using the toilet. As a result, they have to wear large absorbent diapers known as maximum absorption garment or Urine Collection Device, which is disposed of after the spacewalk.
• Liquid Cooling and Ventilation Garment
It’s like long underwear made of Nylon tricot and spandex-laced with plastic tubes. Cool water travels through the umbilical cord or through the backpack and flows through the tubes so as to remove the excess of heat.
• EMU Electrical Harness (EEH)
It’s a set of communications wires and bio-instruments worn inside the suit that provides connections to the radio and bio-instruments in the suit’s backpack. It facilitates to monitor the astronaut’s vital signs like respiration rate, heart rate, etc.
• Communications Carrier Assembly (CCA)
It’s a fabric cap equipped with microphones and speakers allowing hands-free radio communication within the space suit.
• Lower Torso Assembly (LTA)
It’s a one-piece unit which is the lower half of EMU containing pants, knee and ankle joints, lower waist and boots.
• Hard Upper Torso (HUT)
• In-Suit Drinking Bag (IDB)
IDB is a plastic pouch which can hold 32 ounces of water and has a small tube attached to a straw near the astronaut’s mouth.
It’s padded in the rear for comfort and is fitted with numerous components like a valve for carbon dioxide removal, a metallic gold-covered visor to filter sunlight, adjustable blinders, headlamps, TV camera, and a slot containing a serial bar in case someone feels hungry during the spacewalk.
• Airlock Adapter Plate (AAP)
It’s a frame mounted on the airlock wall that holds the EMU pieces while the astronaut is suiting up.
• Primary Life-Support Subsystem (PLSS)
It’s the backpack carrying oxygen tanks, carbon dioxide filters, cooling water, electrical power, ventilating fans, radio, and warning systems. Inside, the air flows into a charcoal cartridge to remove bad odours and travels to the carbon dioxide scrubber cartridge. Then it goes through a fan to the sublimator that removes water vapor and returns it to the cooling water supply. This air flow is maintained at the temperature of 12.8 degree Celsius.
The astronaut can make changes to the temperature, pressure, and airflow through the controls ion the DCM. The PLSS provides a continuous supply of oxygen and removal of carbon dioxide for seven hours.
• Contaminant Control Cartridge
It’s the replaceable part of the EMU’s life support system that removes carbon dioxide from the astronaut’s air supply.
• Secondary Oxygen Pack
It’s situated below the PLSS and contains two oxygen tanks carrying 2.6 lb at 408 atm tank pressure which is enough to be supplied for 30minutes. It turns on automatically as soon as the oxygen pressure in the suit drops below 0.23 atm.
• Servicing and Cooling Umbilical
It is an umbilical cord carrying tubes for oxygen, cooling water and electrical wires for power.
• Display and Control Module (DCM)
The DCM is mounted on the chest and includes all the switches, gauges, valves, and LCD display that are crucial for operating the PLSS. It carries the following accessories.
1. Servicing and Cooling Umbilical (SCU): It renders facilities like oxygen supply, power, communication, and water while the astronaut is in the airlock, preparing for the spacewalk.
2. Airlock Adapter Plate: It is located on the wall of the airlock and holds all the EMU pieces while one is suiting up.
3. Helmet Lights and Camera: These devices are fitted on the EVA over the helmet. These allow the ground controllers and space travelers to see in the dark.
4. Sleeve-mounted mirrors and checklists: The mirrors help in seeing the DCM displays while the checklist reminds them of the course that they have to complete during the seven-hour spacewalk.
Evolving Technology of Space Suits
Space suits have evolved to be more and more advanced as well as complicated with time. It started with pilots wearing suits in aircraft, then astronauts in space shuttles followed by special garments for space walking. Looking at the current situation, the human is aiming to land on the red planet and asteroids having a carbon dioxide atmosphere where the present space suit technology won’t work.
As a result, attempts are being made to design more viable suits with better life support systems with improved humidity control, carbon dioxide removal, and oxygen regulation. It would be quite convenient to have suits that can be repaired in space by the crew members and can work in both Mars and other places in space. Let’s take a look at some of the emerging space suit technologies that are soon going to be implemented.
Figure 8: Z-2 Space Suit Sample
It’s the first generation of new suits that has a rear entry hatch implying that instead of wearing it as a garment, the astronauts can enter through the back port. The upper torso is more durable, gloves and helmets have been redesigned and there is electroluminescent wiring which allows astronauts to be visible even in the dark. The Z-2 suit is going through the testing phase after which the results will be implemented into the Z-3 suit. The latter is slated to be launched by the year 2018 or 2019.
Figure 9: Dr. Dava Newman demonstrating the working of Bio Suit
Bio Suit is a skin tight space suit developed by MIT professor Dr. Dava Newman. In this, the astronaut is scanned to generate a mannequin which in turn is used to build a custom fit space suit. The suit applies pressure on the body thereby preventing the tissues from expanding and blood from congealing. It carries a network of filaments that allow a normal walk and mobility. Besides, it doesn’t use gas for pressure and hence can be easily repaired in the space itself.
Figure 10: Aurora Wearables Space Suit
It’s a space suit which has been designed using the wearable technology. It’s an internet connected suit which is currently being used on the International Space Station. It features a vision board on the sleeve and a “wearable hug”, which squeezes astronauts’ shoulders whenever someone from the family at home thinks about them. It has also got a 3D printer in the pocket which can readily deliver tools and parts directly to the suit.
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