Spacesuits
Spacesuits are not just clothing worn by astronauts on their journey into space; it's more like an individual spacecraft. These are fully equipped with all the essential elements that are crucial for creating an environment that protects astronauts from the extreme conditions of outer space. Astronauts are required to wear spacesuits while working in Earth orbit, on the surface of the Moon, or elsewhere in space. These can be broadly categorized as IVA (Intravehicular Activity), EVA (Extravehicular Activity) and IEVA (Intra/Extra Vehicular Activity ); depending on the purpose they serve.
Figure 1: Space Suits
Space is devoid of many important elements like oxygen and contains several harmful radiations with temperatures ranging from 120 degrees C to -100 degrees C. To address this, a space suit is designed with systems that provide an adequate amount of air pressure . , oxygen and also removes carbon dioxide. Furthermore, it also offers protection against radiation and micrometeoroids that move at high speeds in space. Furthermore, a spacesuit must also provide comfort and mobility so that astronauts can move around easily and communicate with each other.
Space suit work
As mentioned above, a spacesuit is more like a spaceship and is therefore equipped with various facilities that allow astronauts to explore space as freely as one can survive on Earth. To provide an Earth-like environment, spacesuits perform the following functions.
Atmospheric pressure
Since space carries very little or no air pressure, this can cause our bodily fluids to boil. Fortunately, a spacesuit provides an adequate amount of pressure (usually 0.29 atm) so that bodily fluids remain in a liquid state. It works like an inflated balloon, restricted by Neoprene-coated fibers.
Oxygen supply
Due to low atmospheric pressure, normal air (containing 78% nitrogen, 21% oxygen and 1% other gases) cannot be used by a spacesuit as it would reduce oxygen concentrations in the body. As a result, he gets pure oxygen from the spacecraft through an umbilical cord or a life support backpack.
Carbon dioxide removal
The air we exhale contains carbon dioxide that needs to be removed from the confined area of a spacesuit. To serve this purpose, it contains lithium hydroxide canisters located in the spacecraft or spacesuit life support system.
Dealing with extreme temperatures
To deal with the extreme temperatures of space, spacesuits are insulated with numerous layers of fabric and covered with reflective outer layers. They are also equipped with fans or heat exchangers to blow cold air or use water-cooled clothing. If excess heat is not removed, the sweat produced by the body turns into steam and fogs the helmet, dehydrating the astronaut.
Protection against harmful radiation
Spacesuits are equipped with reflective Mylar coatings that offer limited protection against radiation. However, it does not protect against solar flares, which is why spacewalks are only carried out during low solar activity.
Enable communications
The backpacks worn by astronauts contain transmitters and receivers, while the headsets are equipped with a microphone and earphones. This helps them communicate with ground controllers or other fellow astronauts.
Providing clear vision
Astronaut helmets are made of durable plastic or polycarbonate and also equipped with tinted visors to reduce glare. Newer costumes even carry lights that allow them to look into shadows.
Micrometeoroids
There are often several micrometeoroids traveling through space at high speeds, and therefore there is a danger of collision. To deal with this, spacesuits are equipped with multiple layers of durable fabrics like Dacron or Kevlar. This also prevents the suit from tearing when exposed to the outer atmosphere of other planets or the moon.
Mobility
To allow astronauts to move freely while wearing the suit, it is designed with special joints and cones that make it easier for the body's joints to flex as needed. To ensure mobility within the spacecraft, it contains footrests and handrests so that astronauts can move from one place to another without being carried away by the weightless environment.
Furthermore, NASA has even developed some rocket maneuvering devices with the help of which astronauts can move freely anywhere without being tied to the spacecraft. Examples of such devices are the Manned Maneuvering Unit (MMU) and the Simplified Aid for Extravehicular Activity Rescue (SAFER). The former is a gas-powered chair with a joystick, while the latter is a nitrogen-powered device fitted to the backpack.
History
The history of fully pressurized suits dates back to the 1930s. It began with the engineering of pressurized flight suits intended to be used by aircraft pilots. However, the first human-born spacesuit was the Soviet SK-1, worn by Yuri Gagarin in the year 1961. Below is the timeline representing the evolution of spacesuit technology.
Flight suits
Figure 2: Aircraft crew wearing flight suits
When the aircraft was developed, pilots needed a solution to deal with low atmospheric pressure and lack of oxygen at high altitudes, like a mountaineer. However, the suits were designed in case the pressurized cabin failed. These suits were made of neoprene rubber-coated fabric that could inflate like a balloon. In addition, there was also a rigid fabric that restricted the suit and directed pressure inside the pilot. There were hoses connecting the suits to the plane that supplied oxygen.
Mercury
Figure 3: NASA Mercury Space Program Crew
When NASA's first human spaceflight program, called Mercury, began in 1958, they kept the basic flight suit design and added a few layers of aluminized Mylar over the neoprene rubber. Other than that, the uniform also included a helmet secured by a ring at the collar, lace-up boots and a pair of gloves. The hoses connecting the suit to the spacecraft provided oxygen while the astronauts had to carry an external fan to remove excess heat.
Twins
Figure 4: NASA Gemini Space Program Astronauts
Since the Mercury suit was not designed for spacewalks, the astronauts needed something more advanced. So NASA created the Gemini Program to design suits that could be used for spacewalks and not just in the event of cabin pressure failure.
This suit carried a human-shaped bladder made of neoprene rubber secured by a net. It also had Teflon-coated nylon layers to provide protection against micrometeoroids. Furthermore, refrigerated air and oxygen were supplied through an umbilical cord.
Apollo
Figure 5: Astronauts wearing spacesuits in Apollo
Soon the astronauts realized that the air cooling mechanism equipped in the Gemini suits was not working well. Additionally, they were exhausted from the spacewalk, which caused their sweat to vaporize, fogging up their helmets. As a result, some add-ons were implemented to design that could be used for both spacewalks and space flying. It was a multi-layer pressurized suit containing five layers of aluminized Mylar, two layers of Kapton, and some Teflon-coated fabric. In addition, it was accompanied by water-cooled nylon underwear, boots, gloves, a communication cap and a plastic helmet.
To walk on the Moon, the suit was combined with boots, gloves with rubber spikes, visors over the helmet and a life support backpack that took care of oxygen supply, water cooling and carbon dioxide removal. It weighed 180 pounds on Earth and 30 pounds on the moon.
Occurrence of the Challenger disaster
Figure 6: Astronauts on NASA's Orbiter Challenger space shuttle
Previously, astronauts were issued brown suits to use in case of an emergency, such as cabin pressure failure. Later, when Space Shuttle flights became routine, they stopped using it during takeoffs. They started to wear light blue overalls accompanied by black boots and impact-resistant plastic helmets, facilitating communication.
In 1986, NASA's space shuttle Orbiter Challenger disintegrated 73 seconds into flight, popularly known as the Challenger Disaster. This led to the deaths of its 7 crew members, including 5 NASA astronauts and 2 payload specialists. After analyzing the situation, NASA made it mandatory for all astronauts to wear pressure suits during takeoff and reentry. These suits were equipped with a helmet, boots, gloves, communication cap, parachute and inflatable life jacket.
Extravehicular Mobility Unit
Figure 7: Extravehicular Mobility Unit Components
As advancements in space exploration have led to more and more space travel and spacewalks, soft fabrics have been combined with hard components to improve support, mobility and comfort for space travelers. This process was introduced in 1981, but now contains many changes and changes. Today it is one of two suits used on the International Space Station (ISS).
It contains 13 layers, including eight layers of micrometeoroid thermal suit, two layers of inner cooling suit, two layers of pressure suit, and an outer cover. It makes use of materials like Nylon Tricot, Spandex, Urethane Coated Nylon, Dacron, Kevlar, Nomex, etc. Previously, each astronaut received an individually tailored suit, but now it is designed in varying sizes to fit any astronaut.
An EMU has the following basic components
• Maximum Absorption Piece
It can 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. Therefore, one cannot simply enter and exit the spacecraft just to use the bathroom. As a result, they have to wear large absorbent diapers, known as maximum absorbency garments or urine collection devices, which are discarded after the spacewalk.
• Clothing for liquid cooling and ventilation
It's like long underwear made of nylon and spandex knitted with plastic tubes. Cold water passes through the umbilical cord or backpack and flows through the tubes to remove excess heat.
• EMU Electrical Harness (EEH)
It is a set of communication wires and bioinstruments worn inside the suit that provide connections to the radio and bioinstruments in the suit's backpack. It facilitates monitoring of the astronaut's vital signs, such as respiratory rate, heart rate, etc.
• Communications Carrier Assembly (CCA)
It is a fabric cover equipped with microphones and speakers that allow hands-free radio communication inside the spacesuit.
• Lower Torso Assembly (LTA)
It is a one-piece unit that is the lower half of the EMU containing pants, knee and ankle joints, lower waistband and boots.
• Rigid upper torso (HUT)
• In-suit beverage bag (BID)
The BID is a plastic bag that can hold 32 ounces of water and has a small tube attached to a straw near the astronaut's mouth.
• Helmet
It is padded on the back for comfort and is equipped with various components such as a valve for removing carbon dioxide, a metal visor covered in gold to filter sunlight, adjustable blinds, headlights, a TV camera and a slot containing a bar. serial in case someone feels hungry during the spacewalk.
• Airlock Adapter Plate (AAP)
It is a frame mounted on the wall of the airlock that holds the EMU parts while the astronaut suits up.
• Primary Life Support Subsystem (PLSS)
It is the backpack that carries oxygen tanks, carbon dioxide filters, cooling water, electricity, fans, radio and warning systems. Inside, air flows to a carbon cartridge to remove bad odors and goes to the carbon dioxide purifier cartridge. It then passes through a fan to the sublimator, which removes the water vapor and returns it to the cooling water source. This airflow is maintained at a temperature of 12.8 degrees Celsius.
The astronaut can make changes to temperature, pressure and airflow through the DCM controls. The PLSS provides continuous oxygen delivery and carbon dioxide removal for seven hours.
• Contaminant control cartridge
It is the replaceable part of the EMU life support system that removes carbon dioxide from the astronaut's air supply.
• Secondary oxygen pack
It is situated below the PLSS and contains two oxygen tanks carrying 2.6 pounds at a tank pressure of 408 atm, which is sufficient to be supplied for 30 minutes. It turns on automatically as soon as the oxygen pressure in the suit drops below 0.23 atm.
• Maintenance and Cooling Umbilical
It is an umbilical cord that carries tubes for oxygen, cooling water, and electrical wires for power.
• Display and Control Module (DCM)
The DCM is mounted in the trunk and includes all switches, gauges, valves and LCD display that are crucial to operating the PLSS. It carries the following accessories.
1. Maintenance and Cooling Umbilical (SCU): Provides facilities such as oxygen, power, communication and water supply while the astronaut is in the airlock, preparing for the spacewalk.
2. Airlock Adapter Plate: This is located on the airlock wall and holds all EMU parts while one of them is adapting.
3. Helmet lights and camera: These devices are mounted on the EVA over the helmet. This allows ground controllers and space travelers to see in the dark.
4. Sleeve-mounted mirrors and checklists: The mirrors help them see the DCM monitors, while the checklist reminds them of the route they must complete during the seven-hour spacewalk.
Evolving Spacesuit Technology
Spacesuits have evolved to be increasingly advanced and complicated over time. It started with pilots wearing suits in aircraft, then astronauts in space shuttles, followed by special suits for spacewalks. Looking at the current situation, the human intends to land on the red planet and asteroids with a carbon dioxide atmosphere where the current spacesuit technology will not work.
As a result, attempts are being made to design more viable suits, with better life support systems, with better humidity control, carbon dioxide removal and oxygen regulation. It would be quite convenient to have suits that could be repaired in space by crew members and could work both on Mars and elsewhere in space. Let's take a look at some of the emerging spacesuit technologies that will be implemented soon.
Z Fact
Figure 8: Z-2 Space Suit Sample
It's the first generation of new suits to have a rear entry hatch, meaning that instead of wearing them as clothing, astronauts can enter through the rear door. The upper torso is more durable, the gloves and helmets have been redesigned, and there is electroluminescent wiring that allows astronauts to be visible even in the dark. The Z-2 suit is currently undergoing the testing phase, after which the results will be implemented into the Z-3 suit. The latter is expected to be launched by 2018 or 2019.
Biological fact
Figure 9: Dr. Dava Newman demonstrating how the Bio Suit works
Bio Suit is a waterproof spacesuit developed by MIT professor Dr. Dava Newman. In it, the astronaut is scanned to generate a mannequin which, in turn, is used to build a personalized spacesuit. The suit applies pressure to the body, preventing tissues from expanding and blood from freezing. It carries a network of filaments that allow normal walking and mobility. Furthermore, it does not use gas for pressure and therefore can be easily repaired in-house.
Aurora Wearables
Figure 10: Aurora Wearables Spacesuit
It is a spacesuit designed using wearable technology. It's an internet-connected suit that's currently being used on the International Space Station. It features a vision board on the sleeve and a “wearable hug” that squeezes astronauts' shoulders whenever someone in the family at home thinks about them. He also has a 3D printer in his pocket that can deliver tools and parts directly to the suit.
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