How does the spacesuit resist pressure?

Function of spacesuit

Space suit is a personal closed equipment to protect astronauts' life activities and work ability. It can protect human body from vacuum, high and low temperature, solar radiation, micrometeoroids and other environmental factors. In a vacuum environment, nitrogen contained in human blood will become gas, which will expand the volume. If people don't wear pressurized and sealed spacesuits, their lives will be in danger because of the great difference in air pressure between inside and outside.

Space suit is a multifunctional suit developed on the basis of pilot's closed suit. Early spacesuits could only be used by astronauts in the cockpit of spacecraft, and later spacesuits for extravehicular use were developed. Modern new extravehicular spacesuit has liquid-cooled structure, which can be used for astronauts to leave the cabin or explore the moon.

[Edit this paragraph] Classification of spacesuits

Space suits are divided into emergency space suits used in the cabin and space suits used outside the cabin according to their functions. In-cabin spacesuit is used in the cabin of spacecraft. When the pressure drops suddenly, the astronauts put it on in time and connect the oxygen and gas supply system in the cabin. This kind of clothing will immediately pressurize and supply air, and can provide certain temperature protection and communication functions, so that astronauts can return safely when the spacecraft fails. Astronauts generally don't wear spacesuits when the spacecraft is in orbit.

[Edit this paragraph] Structure of spacesuit

Personal protective life-saving equipment to protect the life safety of astronauts in space flight, also known as spacesuit or spacesuit. Spacesuit can form a microclimate suitable for astronauts' life. It is structurally divided into six layers:

① Comfortable underwear: Astronauts can't wash and change clothes during a long flight, and a lot of sebum and sweat will pollute underwear, so choose cotton knitwear with soft texture, good hygroscopicity and breathability.

② Insulation layer: The insulation layer is used to maintain a comfortable temperature environment in the case of a small range of ambient temperature changes. Choose materials with good warmth retention, high thermal resistance, softness and light weight, such as synthetic fiber wadding, wool and silk floss.

③ Ventilation suit and water-cooled suit (liquid-cooled suit): When the astronaut's body temperature is too high, the ventilation suit and water-cooled suit have different heat dissipation methods. If the heat generated by the human body exceeds 350 kcal/hour (such as outdoor activities), the ventilation suit can not meet the heat dissipation requirements, and then the water-cooled suit will cool down. Ventilation clothes and water-cooling clothes mostly use compression-resistant, durable and soft plastic pipes, such as PVC pipes or nylon films.

④ Airtight seal: In a vacuum environment, the life safety of astronauts can only be guaranteed if there is a certain pressure around their bodies. Therefore, the airtight layer adopts neoprene coated tape, which has good air tightness. The limiting layer is made of high strength and low elongation fabric, and polyester fabric is generally used. Because it is difficult to move after pressure, various joints have adopted various structural forms, such as mesh cloth, corrugated pipe, orange flap and so on. , and adopts airtight bearing rotating structure to improve its maneuverability.

⑤ Thermal insulation: When astronauts leave the cabin, the thermal insulation layer plays the role of overheating or supercooling protection. It is made of multilayer aluminized polyimide film or polyester film with non-woven fabric sandwiched between layers.

⑥ Protective cover: It is the outermost layer of the spacesuit, which requires fire prevention, heat radiation prevention and protection from various factors in space (meteor, cosmic rays, etc.). ) to the human body. This layer is mostly aluminum-plated fabric.

Helmets, gloves, boots, etc. It also matches the spacesuit.

Spacesuit for cabin use

A spacesuit consists of a helmet, clothes, gloves and boots. The helmet is connected to the clothing through the collar. The face window on the helmet can be opened and closed at will at ordinary times, and it can be locked automatically or manually within a few seconds in case of emergency. The extravehicular spacesuit consists of outer cover, vacuum insulation layer, airtight limiting layer, ventilation structure and liquid-cooled suit. Gloves and sleeves are connected by wrist connectors, which is convenient to take off and put on. Some boots are integrated with clothes, while others are worn separately from clothes. The full set of space suits weighs about 30 ~ 40 kilograms.

The other two components of a spacesuit are gloves and boots that can be connected at any time. Gloves and clothing are connected by wrist rings, which is the continuation of the pressure layer of clothing. It should conform to the wearer's hand shape, can be put on and off quickly, and each finger joint has a corrugated structure, which is convenient for operation. Space boots are composed of extravehicular pressure boots and thermal protection boots, in which the pressure boots are the continuation of the airtight pressurization limiting layer of clothing. Usually, the ankle joint is designed on the pressure boots and connected with the pressure suit. There is also a waste collection device inside the spacesuit, which is used to collect, store and transport urine and feces in an emergency.

Extravehicular spacesuit

In addition to all the layers inside the extravehicular space, the extravehicular space suit has three layers: the first layer is a vacuum insulation layer, which is used to protect astronauts from overheating and supercooling in the extravehicular space when working in the extravehicular space or moving on the surface of the moon and other planets, and to prevent heat loss inside the suit. The second type is liquid cooling suit, which is made by changing the gas in the ventilation and heat dissipation layer tube of the space suit in the cabin into liquid. Astronauts sometimes work outside the cabin for several hours, and their bodies generate a lot of heat, which can not meet the requirements of gas heat dissipation, while liquid cooling working medium can dissipate heat well. The third is the outermost layer, which not only has the functions of preventing high heat, wear and tear, and protecting the inner layer, but also has the function of preventing solar radiation and the interface connecting other accessories. For example, it is connected with the umbilical cord of astronauts when they are out of the cabin, with the life-support environmental equipment carried on their backs, and with the space maneuvering flight mechanism.

Spacesuit helmet consists of helmet shell, window structure and collar. At present, there are two kinds of helmets used in manned spaceflight: soft helmets and hard helmets, and hard helmets are divided into fixed helmets and rotating helmets. Soft helmets are mostly used as components of space suits in the cabin. There are airtight movable bearings on the collar of the rotating helmet, but the increase of sealing links will reduce the airtightness and structural reliability and increase the design difficulty.

Taking the fixed fully transparent bell jar helmet as an example, this paper introduces its structure. The helmet shell is the main body of the helmet, and its material should have the advantages of high strength, impact resistance and sufficient heat resistance. It has good optical properties at its window position. There are hard pads and soft pads on the inner wall of the helmet, and thin tubes are embedded in the pads, which have the functions of shock absorption, heat insulation, noise elimination, ventilation and oxygen supply. Its inner cavity should be suitable for wearing a communication helmet, allowing the head to rotate left and right inside, and the size should be suitable for the wearer's head shape. There is also a space for installing physiological test components, which is conducive to discharging carbon dioxide and water vapor exhaled by the human body.

In addition to the above requirements, windows should also have good optical performance and wide field of vision. In addition to good light transmission, the front window of the head shell should be provided with anti-fog and dehumidification measures, because astronauts will encounter a low temperature of-150℃ when they leave the cabin, and the temperature in the front window will also drop. When it drops below the dew point of the air, fog will form on the window, which will hinder the astronauts' sight. At present, the methods used are ventilation and dehumidification, double-sided window opening, electric heating window opening and chemical antifogging agent to ensure the transparency of windows. Otherwise, it will affect the implementation of the space mission. For example, in 1966, when the astronauts of Gemini 9 spacecraft in the United States were flying in space, they could not see the outside scene clearly because of the fog on the window, and failed to complete the specific space mission in the spacewalk.

Collar is the key component connecting clothing and helmet, which is divided into upper and lower circles. When wearing clothing and helmet, you should connect the upper and lower rings first, and then connect the helmet and clothing. It is required to be easy to put on and take off, with good air tightness and connection strength. In case of emergency, there should be a mechanism that can make the wearer quickly disconnect, connect and lock, so as to facilitate the timely disconnection or connection with the helmet or clothing.

[Edit this paragraph] The role of spacesuits

Spacesuit, also known as spacesuit, is a kind of clothing system worn by astronauts in manned space flight. In fact, it is a necessary personal protective life-saving equipment for astronauts. Functionally, there are two kinds of spacesuits: in-cabin spacesuits and extravehicular spacesuits. Judging from the internal pressure of clothing, there are low-pressure spacesuits and high-pressure spacesuits; Structurally, it can be divided into soft, hard and soft-hard spacesuits.

At present, both the United States and Russia use both soft and hard spacesuits. No matter what kind of spacesuit is composed of multiple layers, they are interconnected to form a whole spacesuit, but the quality of each layer should be high, light and not too thick, so as not to affect the actions of astronauts. Taking the low-pressure spacesuit used in the cabin as an example, its basic structure and functions are as follows; From the nearest inner layer, the first layer is underwear, choose pure cotton or cotton and linen uniforms. The second layer is a thermal insulation layer, which is combined with underwear and made of wool products or synthetic fiber sheets to play a role in thermal insulation. The third floor is a ventilation and heat dissipation layer with unique structure. It is made of long micro pipes connected to clothes. When the human body is isolated from the outside world, it can take out the heat, moisture and smell generated by the human body. The fourth layer is the airtight pressure limiting layer, which not only needs to be inflated and pressurized to make the body have enough pressure, but also can not make the clothes too inflated to prevent external wear, and also can make all joints move freely. Therefore, the material selection and design of this layer structure is difficult, and it is the key layer of aerospace clothing. The fifth layer is insulation layer, also called vacuum insulation layer. The space suit in the cabin can be without this layer. For example, the spacesuits used by the Apollo spacecraft and the space shuttle in the United States do not have this layer, while the spacesuits used by the Soviet Ascension spacecraft and the Russian Soyuz spacecraft all have this layer. This is composed of 5~7 layers of aluminized polyester films, which are separated by mesh objects and glued together to form a shield. It has good heat insulation and radiation protection, and the extravehicular spacesuit must have this layer. The outermost layer is the outer cover. This kind of coating needs strong wear resistance and high temperature resistance. In addition to protecting the inner layer from damage, we should also pay attention to the color, generally white or golden yellow is better.

[Edit this paragraph] The development of spacesuits

The first person in the world to use spacesuit equipment was American adventurer Willie Post. In the early 1930s, he flew Winnie the Pooh to the stratosphere in the challenge of flying over the North American continent. At that time, the high-altitude flight pressure suit that Post wore was an airbag, which was blown up by the air pressure generated by the pressure supply device of the engine.

First generation spacesuit

The modern spacesuit came out in America in 196 1. In May of that year, Aaron Shepard was the first to successfully fly the suborbital flight of the project mercury, which was the earliest manned spacecraft program in the United States. The spacesuit used in the flight was improved from the MK-4 pressure suit worn by the pilots of the US Navy's high-performance fighter at that time. This spacesuit consists of a protective layer covered with neoprene and an alumina-treated reinforced nylon inner insulation layer. Elbow and knee are sewn into metal chains, which are easy to bend. However, it is difficult for astronauts to move their bodies when the internal pressure increases.

Second and third generation spacesuits

In the mid-1960s, when the Gemini project was implemented, the United States developed the second-generation spacesuit. This kind of space suit is covered with a layer of PTFE net outside the air pressure sealed pressure bag, which is easy to bend even if the air pressure makes the space suit expand as a whole. Because the Gemini program requires astronauts to go into space to meet or dock in orbit, the sports performance of this spacesuit is excellent.

The third generation spacesuit was used in the implementation of Apollo program. Lunar activity is different from floating in space. You must walk on the rocky surface of the moon and bend down to collect rock samples. In addition, it also requires protecting astronauts from strong solar radiation and preventing tiny meteorites falling from the sky from being damaged.

This kind of spacesuit is made into flexible folds around the joints, which greatly improves the sports performance. However, you must wear special underwear. This kind of mesh underwear, which covers almost the whole body, is sewn into a mesh tube 100 meter long and as thin as spaghetti. Cold water flows through the pipe, absorbs the heat emitted by the astronauts and discharges it into space, so the astronauts feel very comfortable after wearing it. The spacesuit worn outside underwear consists of several layers: inner insulation layer, pressure layer and limiting layer (to inhibit the expansion of pressure layer), and the outermost layer is covered with a protective layer made of PTFE and glass fiber. Then put on a helmet made of reinforced resin, gloves with almost the same layers as the spacesuit, and boots with metal mesh, and you will have a complete Apollo spacesuit.

Compared with the previous spacesuit, the fundamental difference of Apollo spacesuit is that it adopts a portable life support system, that is, the life support system is fixed on the back for oxygen supply, carbon dioxide purification and body heat dissipation.

Space shuttle's spacesuit

Now the spacesuit used by astronauts on the space shuttle can be said to be the fourth generation spacesuit. Prior to this, space suits were all customized, which not only cost a lot of money and time to develop and produce, but also can only be used once, which is far from meeting the new demand.

The spacesuit used for the space shuttle is not customized. According to the shape of the human body, it is divided into several parts, standardized into several sizes from "extra large" to "extra large", and then mass-produced and processed into garments. Astronauts can get a satisfactory suit by choosing suitable parts and recombining them. After use, it will not be sent to the museum as in the past, but the spacesuit will be decomposed again, and all parts will be cleaned and reused. The planned service life is greater than 15 years.

In the Apollo era, it took 1 hour to put on a spacesuit. Now it only takes 10 ~ 15 minutes to put on the space suit of the space shuttle (including the life support system). The new life support system can provide the astronauts with necessary oxygen, cooling water and electricity for 7 hours. Not only that, the helmet can also supply 500 ml of drinks and a small amount of space food.

As for the treatment of urine and feces, you must defecate in the cabin before carrying out extravehicular activities, and urine can be discharged in the spacesuit because there is a urine suction device. At present, there are only devices for men, and diapers for women are under development. Female astronauts will not have to worry about urinating in the future.

In order to welcome the arrival of the space station era, NASA is now working hard to develop new spacesuits. Although it is possible to build a space station with a spacesuit for the space shuttle, astronauts should be prepared before entering space activities. That is, you must breathe pure oxygen for 4 hours, or stay in the cabin with the air pressure of 0.69 mm Hg for about 12 hours, and then breathe pure oxygen for 40 minutes, so as to expel nitrogen from the body and make the body adapt to the low-pressure environment. Without such preparation, because there is only 0.3 atmospheric pressure in the space suit, the nitrogen in the body will form bubbles due to rapid decompression, making astronauts suffer from diving disease like divers. Obviously, this kind of spacesuit is difficult to meet the needs of frequent activities in space in the future. According to NASA's forecast, in the space age, each astronaut needs to work in space 1000 hours a year, so the spacesuit is required to be durable and greatly reduce the cost.

Compared with the previous spacesuit, the spacesuit being developed now is obviously different in appearance. The whole body is a rigid structure like metal armor, and only the joints are foldable flexible structures. The internal pressure of this spacesuit can be raised to 0.54 atmospheric pressure, so astronauts do not need the preparation process before wearing this new spacesuit, nor do they have to worry about caisson disease. However, the increase of internal pressure makes this new spacesuit look clumsy and has poor maneuverability. At present, this trial spacesuit weighs 90 kilograms, so it is impossible to walk on the ground in it. Fortunately, in space, even the heaviest objects will lose weight.

The manufacturing and research time of spacesuit is still quite short, and the future spacesuit will be more suitable for the needs of human spaceflight and space life!

[Edit this paragraph] Steps to wear a spacesuit

There are strict steps and sequences for astronauts to wear extravehicular spacesuits, and the sequence of different types of spacesuits is different. Here, we take the American space shuttle extravehicular spacesuit as an example to introduce. The whole trimming process is completed in 10 steps:

(1) wear strong diapers.

② Wear liquid-cooled ventilation clothes.

③ Self-contained bioelectronic coupling device. On this equipment, there are sensors to measure the astronauts' heart rate and electronic devices to communicate with the outside world.

(4) Some small operation procedures, including coating anti-fog paste on the face window of the helmet, installing a small reflector on the wrist of the left sleeve of the garment, installing a small food bag and a drinking bag on the chest of the upper body of the garment, installing a lighting lamp and a TV camera on the helmet, and finally connecting the communication cap with the bioelectronic coupling device. The above four steps are all preparations before getting dressed.

⑤ Lower body with clothes on. The lower body varies in size and can be used by astronauts of different sizes. There is a large load-bearing joint at the waist of the lower body clothing, which provides convenience for astronauts to bend over and turn around.

6 upper body with clothes. Before putting on the upper body, the cooling umbilical cord of the air lock should be inserted into the interface of the display control box on the chest of the garment to provide cooling water, oxygen and electricity for the garment. Because the airlock of the space shuttle is only 2.0 meters high and the diameter is 1.6 meters, it is very crowded for two astronauts to wear spacesuits inside, so the upper part of the spacesuit is hung on the bracket of the bulkhead of the airlock. In this way, when astronauts want to put on the upper part of the costume, they must squat down, extend their arms upward and take a diving posture of a diver to get into the costume. After the clothes are put on, the sealing rings are connected together, and then various supply pipes are connected with the clothes.

⑦ Wear communication cap, helmet and gloves. Once wearing helmets and gloves, astronauts can't breathe the air in the airlock, but breathe the oxygen provided by the space shuttle orbiter through the umbilical cord.

⑧ Pressurize the clothes and test them by astronauts to ensure that the clothes are airtight and the internal pressure is stable. The test focuses on gas flow, cooling water and battery power.

Pet-name ruby began to breathe pure oxygen, oxygen and nitrogen. That is, the nitrogen in the body is eliminated to prevent decompression sickness.

Attending to close the airlock inner door and decompress the airlock. When the pressure in the airlock cabin drops to zero, open the cabin door outside the airlock cabin, and at the same time, the astronauts should disconnect all the connections between the clothing and the airlock cabin, hook the hook of the safety belt on the fixed rod outside the cabin, and then the astronauts can leave the cabin for spacewalking.

/Tian Fei/spacesuit "Tian Fei" spacesuit Tian Fei extravehicular spacesuit file

Name description: flight spacesuit

Weight: 120kg

Color: white

Cost: about 30 million yuan.

Composition: soft and hard materials, from top to bottom are helmet, upper limbs, trunk, lower limbs, pressure gloves and boots.

Usage: The limbs are equipped with adjustment belts. By adjusting the length of the upper arm, forearm and lower limb, people with a height of 1.60m- 1.80m can wear it.

Endurance: it can support 4 hours of extravehicular activities and can be reused for 5 times.

Upper limb joint

The ingenious use of bionic structure makes joint activities more comfortable.

Wrist mirror

There is a small mirror at the wrist, through which astronauts can check all kinds of switches on themselves at any time.

knapsack

The height 1.3m is the sealed door for the entry and exit of spacesuits. The life support equipment of extravehicular spacesuit is installed in the backpack shell, and the lower end of the backpack shell is equipped with a hanging bag and a spare oxygen bottle. Close the backpack by tightening the rope and operating the closing handle.

helmet

After scientific research, the field of vision of the "Tian Fei" spacesuit helmet is larger than other similar products.

The camera helmet also has a camera, which can shoot astronauts' extravehicular operations.

There is a lighting lamp on both sides of the lighting lamp, which can illuminate the chest part of the clothing and facilitate the astronauts to operate in the dark side.

There are alarm lights on both sides of the alarm lights. Once the clothes are leaked, the alarm lights will flash. There is also a language alarm.

The window has four layers and two layers of pressurized structure, and high-purity nitrogen is filled between the two layers to prevent fogging. The outer layer is a protective window, and the outer layer is a filter window, which has a low refractive index to sunlight and can be pulled down when facing the lighting surface.

gloves

Tailored for each astronaut, it looks particularly thick, a bit like boxing gloves.

The outer layer of thermal protective gloves is fiber fabric, which has two layers of air tightness. Made of special heat-insulating rubber material, it can withstand high temperature as high as 100℃.

Fingertips Fingertips, only one layer is airtight, keeping the touch. There are two layers of vacuum shielding and heat insulation on the back of fingers.

The palm is provided with raised granular rubber at the grip part of the palm, which is mainly anti-slip. Gloves can hold things as thick as pencils.

The heat shield is provided with a foldable heat shield on the back of the hand, which is used to cover the fingers, improve the heat protection ability of this part and ensure the joint activity of the fingers.

look

Specially designed space watch, the material is suitable for special space environment.

Its appearance is bigger than ordinary watches, and its functions are more than ordinary watches. There are three small dials on it, which are hours, minutes and seconds. You can read Beijing time and flight time, or turn the dial to record the time.

Objective Space observation allows astronauts to clearly know the day and night of the earth in the dark space. Ensure that the life rules of astronauts are synchronized with the earth and will not disturb the biological clock.

dress material

Space suits must be vacuum shielded and heat insulated, and the fabrics used must be combined with various weaving methods to meet the strength requirements.

The layered spacesuit consists of six layers: a comfort layer made of cotton cloth with special antistatic treatment, a spare air-tight layer made of rubber, a main air-tight layer made of composite joint structure, a limiting layer made of polyester fabric, a heat-insulating layer for heat insulation through thermal reflection, and the outermost outer protective layer. The trunk reaches 7 floors, and the thickest is that it has 20 floors.