A manned spacecraft is designed to fly one or more people into outer space and safely return to Earth after completing the mission.
When designing this class of spacecraft, one of the main tasks is to create a safe, reliable and accurate system for returning the crew to the earth's surface in the form of a wingless descent vehicle (SA) or a space plane. . spaceplane - orbital aircraft(OS) aerospace plane(VKS) is a winged aircraft of an aircraft scheme that enters or is launched into orbit of an artificial satellite of the Earth by means of a vertical or horizontal launch and returns from it after completing the target tasks, making a horizontal landing on the airfield, actively using the glider's lifting force when descending. Combines the properties of both aircraft and spacecraft.
An important feature of a manned spacecraft is the presence of an emergency rescue system (SAS) at the initial stage of launch by a launch vehicle (LV).
The projects of the Soviet and Chinese spacecraft of the first generation did not have a full-fledged rocket SAS - instead, as a rule, ejection of the crew seats was used (the Voskhod spacecraft did not have this either). Winged spaceplanes are also not equipped with a special SAS, and may also have ejection crew seats. Also, the spacecraft must be equipped with a life support system (LSS) for the crew.
The creation of a manned spacecraft is a task of high complexity and cost, therefore only three countries have them: Russia, the USA and China. And only Russia and the USA have reusable manned spacecraft systems.
Some countries are working on the creation of their own manned spacecraft: India, Japan, Iran, North Korea, as well as ESA (European Space Agency, created in 1975 for the purpose of space exploration). ESA consists of 15 permanent members, sometimes, in some projects, they are joined by Canada and Hungary.
First generation spacecraft
"East"
These are a series of Soviet spacecraft designed for manned flights in near-Earth orbit. They were created under the leadership of the General Designer of OKB-1 Sergey Pavlovich Korolev from 1958 to 1963.
The main scientific tasks for the Vostok spacecraft were: studying the effects of orbital flight conditions on the astronaut's condition and performance, testing the design and systems, testing the basic principles of building spacecraft.
History of creation
Spring 1957 S. P. Korolev within the framework of his Design Bureau, he organized a special department No. 9, designed to carry out work on the creation of the first artificial satellites of the Earth. The department was headed by an associate of Korolev Mikhail Klavdievich Tikhonravov. Soon, in parallel with the development of artificial satellites, the department began to carry out research on the creation of a manned spacecraft. The launch vehicle was supposed to be the royal R-7. Calculations showed that it, equipped with a third stage, could launch a cargo weighing about 5 tons into low Earth orbit.
At an early stage of development, the calculations were done by mathematicians of the Academy of Sciences. In particular, it was noted that ballistic descent from orbit could result in tenfold overload.
From September 1957 to January 1958, Tikhonravov's department studied all the conditions for carrying out the task. It was found that the equilibrium temperature of the winged spacecraft, which has the highest aerodynamic quality, exceeds the thermal stability of the alloys available at that time, and the use of winged design options led to a decrease in payload. Therefore, they refused to consider winged options. The most acceptable way to return a person was to eject him at an altitude of several kilometers and then descend by parachute. In this case, a separate rescue of the descent vehicle could not be carried out.
In the course of medical studies conducted in April 1958, tests of pilots on a centrifuge showed that, in a certain position of the body, a person is able to endure overloads of up to 10 G without serious consequences for his health. Therefore, a spherical descent vehicle was chosen for the first manned spacecraft.
The spherical shape of the descent vehicle was the simplest and most studied symmetrical shape, the sphere has stable aerodynamic properties at any possible speeds and angles of attack. The shift of the center of mass to the aft part of the spherical apparatus made it possible to ensure its correct orientation during the ballistic descent.
The first ship "Vostok-1K" went into automatic flight in May 1960. Later, the modification "Vostok-3KA" was created and tested, completely ready for manned flights.
In addition to one failure of the launch vehicle at the start, the program launched six unmanned vehicles, and later six more manned spacecraft.
The spacecraft of the program carried out the world's first manned space flight (Vostok-1), a daily flight (Vostok-2), group flights of two spacecraft (Vostok-3 and Vostok-4) and the flight of a female cosmonaut ("Vostok-6").
The device of the spacecraft "Vostok"
The total mass of the spacecraft is 4.73 tons, the length is 4.4 m, and the maximum diameter is 2.43 m.
The ship consisted of a spherical descent vehicle (weight 2.46 tons and a diameter of 2.3 m), also performing the functions of an orbital compartment, and a conical instrument compartment (weight 2.27 tons and a maximum diameter of 2.43 m). The compartments were mechanically connected to each other using metal bands and pyrotechnic locks. The ship was equipped with systems: automatic and manual control, automatic orientation to the Sun, manual orientation to the Earth, life support (designed to maintain an internal atmosphere close in its parameters to the Earth’s atmosphere for 10 days), command-logical control, power supply, thermal control and landing . To ensure the tasks of human work in outer space, the ship was equipped with autonomous and radio telemetry equipment for monitoring and recording parameters characterizing the state of the astronaut, structures and systems, ultra-shortwave and short-wave equipment for two-way radiotelephone communication of the astronaut with ground stations, a command radio link, a program-time device, a television system with two transmitting cameras for observing the astronaut from the Earth, a radio system for monitoring the parameters of the orbit and direction finding of the spacecraft, a TDU-1 braking propulsion system, and other systems. The weight of the spacecraft together with the last stage of the launch vehicle was 6.17 tons, and their length in conjunction was 7.35 m.
The descent vehicle had two windows, one of which was located on the entrance hatch, just above the cosmonaut's head, and the other, equipped with a special orientation system, in the floor at his feet. The astronaut, dressed in a spacesuit, was placed in a special ejection seat. At the last stage of landing, after braking the descent vehicle in the atmosphere, at an altitude of 7 km, the cosmonaut ejected from the cabin and made a parachute landing. In addition, the possibility of landing an astronaut inside the descent vehicle was provided. The descent vehicle had its own parachute, but was not equipped with the means to perform a soft landing, which threatened the person remaining in it with a serious bruise during a joint landing.
In the event of failure of automatic systems, the astronaut could switch to manual control. The Vostok ships were not adapted for manned flights to the Moon, and also did not allow the possibility of flights of people who had not undergone special training.
Vostok spacecraft pilots:
"Sunrise"
Two or three ordinary chairs were installed on the space vacated from the ejection seat. Since now the crew landed in the descent vehicle, in order to ensure a soft landing of the ship, in addition to the parachute system, a solid-fuel brake engine was installed, which was triggered immediately before touching the ground from the signal of a mechanical altimeter. On the Voskhod-2 spacecraft, designed for spacewalks, both cosmonauts were dressed in Berkut spacesuits. Additionally, an inflatable airlock was installed, which was reset after use.
The Voskhod spacecraft were launched into orbit by the Voskhod launch vehicle, also developed on the basis of the Vostok launch vehicle. But the system of the carrier and the Voskhod spacecraft in the first minutes after launch had no means of rescue in case of an accident.
The following flights were made under the Voskhod program:
"Cosmos-47" - October 6, 1964 Unmanned test flight for testing and testing the ship.
"Voskhod-1" - October 12, 1964 The first space flight with more than one person on board. Crew - cosmonaut-pilot Komarov, constructor Feoktistov and doctor Egorov.
Kosmos-57 - February 22, 1965 An unmanned test flight to test the ship for spacewalk ended in failure (undermined by the self-destruct system due to an error in the command system).
"Cosmos-59" - March 7, 1965 Unmanned test flight of a device of another series ("Zenit-4") with the installed gateway of the Voskhod spacecraft for spacewalk.
"Voskhod-2" - March 18, 1965 The first spacewalk with. Crew - cosmonaut-pilot Belyaev and test cosmonaut Leonov.
"Cosmos-110" - February 22, 1966 Test flight to check the operation of on-board systems during a long orbital flight, there were two dogs on board - Wind and Coal, the flight lasted 22 days.
Second generation spacecraft
"Union"
A series of multi-seat spacecraft for flights in near-Earth orbit. The developer and manufacturer of the ship is RSC Energia ( Rocket and Space Corporation Energia named after S. P. Korolev. The parent organization of the corporation is located in the city of Korolev, the branch is at the Baikonur cosmodrome). As a single organizational structure, it arose in 1974 under the leadership of Valentin Glushko.
History of creation
The Soyuz rocket and space complex began to be designed in 1962 at OKB-1 as a ship of the Soviet program for flying around the moon. At first it was assumed that under the program "A" a bunch of spacecraft and upper stages were to go to the Moon 7K, 9K, 11K. In the future, the project "A" was closed in favor of separate projects around the moon using the spacecraft "Zond" / 7K-L1 and landings on the Moon using the L3 complex as part of the orbital ship-module 7K-LOK and landing ship-module LK. In parallel with the lunar programs, on the basis of the same 7K and the closed project of the Sever near-Earth spacecraft, they began to make 7K-OK- a multi-purpose three-seat orbital ship (OK), designed to practice maneuvering and docking operations in near-Earth orbit, to conduct various experiments, including the transfer of astronauts from ship to ship through outer space.
Tests of 7K-OK began in 1966. After the abandonment of the flight program on the Voskhod spacecraft (with the destruction of the groundwork of three of the four completed Voskhod spacecraft), the designers of the Soyuz spacecraft lost the opportunity to work out solutions for their program on it. There was a two-year break in manned launches in the USSR, during which the Americans were actively exploring outer space. The first three unmanned launches of the Soyuz spacecraft turned out to be completely or partially unsuccessful, serious errors were found in the design of the spacecraft. However, the fourth launch was undertaken by a manned ("Soyuz-1" with V. Komarov), which turned out to be tragic - the astronaut died during the descent to Earth. After the Soyuz-1 accident, the design of the ship was completely redesigned to resume manned flights (6 unmanned launches were performed), and in 1967 the first, on the whole successful, automatic docking of two Soyuz took place (Cosmos-186 and Cosmos-188”), in 1968 manned flights were resumed, in 1969 the first docking of two manned spacecraft and a group flight of three spacecraft at once took place, and in 1970 an autonomous flight of record duration (17.8 days) took place. The first six ships "Soyuz" and ("Soyuz-9") were ships of the 7K-OK series. A variant of the ship was also preparing for flight "Soyuz-Contact" for testing the docking systems of the 7K-LOK and LK module ships of the L3 lunar expeditionary complex. Due to the failure of the L3 lunar landing program to reach the stage of manned flights, the need for Soyuz-Kontakt flights has disappeared.
In 1969, work began on the creation of a long-term orbital station (DOS) Salyut. A ship was designed to deliver the crew 7KT-OK(T - transport). The new ship differed from the previous ones by the presence of a docking station of a new design with an internal manhole and additional communication systems on board. The third ship of this type ("Soyuz-10") did not fulfill the task assigned to it. The docking with the station was carried out, but as a result of damage to the docking station, the ship's hatch was blocked, which made it impossible for the crew to transfer to the station. During the fourth flight of a ship of this type ("Soyuz-11"), due to depressurization in the descent section, G. Dobrovolsky, V. Volkov and V. Patsaev since they were without space suits. After the Soyuz-11 accident, the development of 7K-OK / 7KT-OK was abandoned, the ship was redesigned (changes were made to the layout of the SA to accommodate cosmonauts in spacesuits). Due to the increased mass of life support systems, a new version of the ship 7K-T became a double, lost solar panels. This ship became the "workhorse" of the Soviet cosmonautics of the 1970s: 29 expeditions to the Salyut and Almaz stations. Ship version 7K-TM(M - modified) was used in a joint flight with the American Apollo under the ASTP program. Four Soyuz spacecraft, which officially launched after the Soyuz-11 accident, had solar panels of various types in their design, but these were other versions of the Soyuz spacecraft - 7K-TM (Soyuz-16, Soyuz-19 ), 7K-MF6("Soyuz-22") and modification 7K-T - 7K-T-AF without docking station ("Soyuz-13").
Since 1968, spacecraft of the Soyuz series have been modified and produced. 7K-S. 7K-S was being finalized for 10 years and by 1979 became a ship 7K-ST "Soyuz T", and in a short transitional period, the astronauts flew simultaneously on the new 7K-ST and the outdated 7K-T.
Further evolution of the systems of the 7K-ST spacecraft led to the modification 7K-STM Soyuz TM: a new propulsion system, an improved parachute system, a rendezvous system, etc. The first Soyuz TM flight was made on May 21, 1986 to the Mir station, the last Soyuz TM-34 - in 2002 to the ISS.
The modification of the ship is currently in operation 7K-STMA Soyuz TMA(A - anthropometric). The ship, according to the requirements of NASA, was finalized in relation to flights to the ISS. Astronauts who could not fit into the Soyuz TM in terms of height can work on it. The cosmonauts' console was replaced with a new one, with a modern element base, the parachute system was improved, and thermal protection was reduced. The last launch of the Soyuz TMA-22 spacecraft of this modification took place on November 14, 2011.
In addition to Soyuz TMA, today ships of a new series are used for space flights 7K-STMA-M "Soyuz TMA-M" ("Soyuz TMAC")(C - digital).
Device
The ships of this series consist of three modules: an instrument-assembly compartment (PAO), a descent vehicle (SA), and an amenity compartment (BO).
PJSC has a combined propulsion system, fuel for it, service systems. The length of the compartment is 2.26 m, the main diameter is 2.15 m. The propulsion system consists of 28 DPO (mooring and orientation engines), 14 on each collector, as well as a rendezvous-correcting engine (SKD). ACS is designed for orbital maneuvering and deorbiting.
The power supply system consists of solar panels and batteries.
The descent vehicle contains places for astronauts, life support systems, control systems, and a parachute system. The length of the compartment is 2.24 m, the diameter is 2.2 m. The amenity compartment is 3.4 m long and 2.25 m in diameter. It is equipped with a docking station and an approach system. In the sealed volume of the BO there are cargoes for the station, other payloads, a number of life support systems, in particular a toilet. Through the landing hatch on the side surface of the BO, the cosmonauts enter the ship at the launch site of the cosmodrome. The BO can be used when airlocking into outer space in spacesuits of the "Orlan" type through the landing hatch.
New upgraded version of Soyuz TMA-MS
The update will affect almost every system of the manned ship. The main points of the spacecraft modernization program:
- the energy efficiency of solar panels will be increased through the use of more efficient photovoltaic converters;
- reliability of rendezvous and docking of the spacecraft with the space station by changing the installation of the approaching and orientation engines. The new layout of these engines will make it possible to perform rendezvous and docking even in the event of a failure of one of the engines and to ensure the descent of a manned spacecraft in the event of any two engine failures;
- a new system of communication and direction finding, which will allow, in addition to improving the quality of radio communications, to facilitate the search for a descent vehicle that has landed at any point on the globe.
The upgraded Soyuz TMA-MS will be equipped with GLONASS sensors. At the stage of parachuting and after landing of the descent vehicle, its coordinates obtained from GLONASS/GPS data will be transmitted via the Cospas-Sarsat satellite system to the MCC.
Soyuz TMA-MS will be the latest modification of the Soyuz". The ship will be used for manned flights until it is replaced by a new generation ship. But that's a completely different story...
High-speed transport vehicles differ from vehicles moving at low speed in lightness of construction. Huge ocean liners weigh hundreds of thousands of kilonewtons. The speed of their movement is relatively low (= 50 km/h). The weight of speedboats does not exceed 500 - 700 kN, but they can reach speeds up to 100 km/h. With increasing speed of movement, reducing the weight of the structure of transport vehicles becomes an increasingly important indicator of their perfection. The weight of the structure is especially important for aircraft (airplanes, helicopters).A spaceship is also an aircraft, but it is only designed to move in a vacuum. You can fly through the air much faster than you can swim on water or move on the ground, and in airless space you can reach even higher speeds, but the greater the speed, the more important the weight of the structure. The increase in the weight of the spacecraft leads to a very large increase in the weight of the rocket system, which takes the ship into the planned region of outer space.
Therefore, everything that is on board the spacecraft should weigh as little as possible, and nothing should be superfluous. This requirement creates one of the biggest challenges for spacecraft designers.
What are the main parts of a spacecraft? Spacecraft are divided into two classes: habitable (a crew of several people is on board) and uninhabited (scientific equipment is installed on board, which automatically transmits all measurement data to Earth). We will consider only manned spacecraft. The first manned spacecraft, on which Yu. A. Gagarin made his flight, was Vostok. It is followed by ships from the Sunrise series. These are no longer single-seat, like Vostok, but multi-seat devices. For the first time in the world, a group flight of three cosmonauts - Komarov, Feoktistov, Egorov - was made on the Voskhod spacecraft.
The next series of spacecraft created in the Soviet Union was called Soyuz. The ships of this series are much more complex than their predecessors, and the tasks they can perform are also more difficult. In the United States, spacecraft of various types have also been created.
Let us consider the general scheme of the structure of a manned spacecraft on the example of the American spacecraft "Apollo".
Rice. 10. Scheme of a three-stage rocket with a spacecraft and a rescue system.
Figure 10 shows a general view of the Saturn rocket system and the Apollo spacecraft docked to it. The spacecraft sits between the rocket's third stage and a device that attaches to the spacecraft at the truss, called the bailout system. What is this device for? The operation of the rocket engine or its control system during the launch of the rocket does not exclude the occurrence of malfunctions. Sometimes these malfunctions can lead to an accident - the rocket will fall to Earth. What can happen in this case? The propellant components will mix, and a sea of fire is formed, in which both the rocket and the spacecraft will be. Moreover, when mixing fuel components, explosive mixtures can also be formed. Therefore, if for any reason an accident occurs, it is necessary to take the ship away from the rocket for a certain distance and only after that land. Under these conditions, neither explosions nor fire will be dangerous for astronauts. This is the purpose of the emergency rescue system (abbreviated SAS).
The SAS system includes the main and control engines running on solid fuel. If the SAS system receives a signal about the emergency state of the rocket, it works. The spacecraft separates from the rocket, and the gunpowder engines of the emergency escape system pull the spacecraft up and to the side. When the powder engine finishes its work, a parachute is ejected from the spacecraft and the ship smoothly descends to Earth. The SAS system is designed to rescue cosmonauts in the event of an emergency, during the launch of the launch vehicle and its flight on the active site.
If the launch of the launch vehicle went well and the flight on the active site is successfully completed, there is no need for an emergency rescue system. After the launch of the spacecraft into low Earth orbit, this system becomes useless. Therefore, before the spacecraft enters orbit, the emergency rescue system is discarded from the spacecraft as unnecessary ballast.
The emergency rescue system is directly attached to the so-called descent or return vehicle of the spacecraft. Why does it have such a name? We have already said that a spacecraft going on a space flight consists of several parts. But only one of its components returns to Earth from a space flight, which is why it is called a return vehicle. The returnable or descent vehicle, unlike other parts of the spacecraft, has thick walls and a special shape that is most advantageous in terms of flight in the Earth's atmosphere at high speeds. The reentry vehicle, or command compartment, is the place where the astronauts are during the launch of the spacecraft into orbit and, of course, during the descent to Earth. It installs most of the equipment with which the ship is controlled. Since the command compartment is intended for the descent of cosmonauts to Earth, it also contains parachutes, with the help of which the spacecraft is braked in the atmosphere, and then a smooth descent is carried out.
Behind the descent vehicle is a compartment called the orbital. In this compartment, scientific equipment is installed, which is necessary for conducting special research in space, as well as systems that provide the ship with everything necessary: air, electricity, etc. The orbital compartment does not return to Earth after the spacecraft has completed its mission. Its very thin walls are not able to withstand the heat that the reentry vehicle undergoes during its descent to Earth, passing through the dense layers of the atmosphere. Therefore, upon entering the atmosphere, the orbital compartment burns out like a meteor.
It is necessary to have one more compartment in spaceships intended for flight into deep space with landing of people on other celestial bodies. In this compartment, astronauts can descend to the surface of the planet, and when necessary, take off from it.
We have listed the main parts of a modern spacecraft. Now let's see how the life of the crew and the operability of the equipment installed on board the ship are ensured.
It takes a lot to ensure human life. Let's start with the fact that a person cannot exist either at very low or at very high temperatures. The temperature regulator on the globe is the atmosphere, i.e. air. And what about the temperature on the spacecraft? It is known that there are three types of heat transfer from one body to another - thermal conductivity, convection and radiation. To transfer heat by conduction and convection, a heat transmitter is needed. Therefore, in space, these types of heat transfer are impossible. The spacecraft, being in interplanetary space, receives heat from the Sun, the Earth and other planets exclusively by radiation. It is enough to create a shadow from a thin sheet of some material that will block the path of the rays of the Sun (or light from other planets) to the surface of the spacecraft - and it will stop heating up. Therefore, it is not difficult to insulate a spacecraft in an airless space.
However, when flying in outer space, one has to fear not overheating of the ship by the sun's rays or its hypothermia as a result of heat radiation from the walls into the surrounding space, but overheating from the heat that is released inside the spacecraft itself. What causes the temperature in the ship to rise? Firstly, man himself is a source that continuously radiates heat, and secondly, a spacecraft is a very complex machine equipped with many devices and systems, the operation of which is associated with the release of a large amount of heat. The system that ensures the life of the crew members of the ship has a very important task - to remove all the heat generated by both the person and the devices in a timely manner outside the compartments of the ship and ensure that the temperature in them is maintained at a level that is required for the normal existence of a person and the operation of devices.
How is it possible in space, where heat is transferred only by radiation, to ensure the necessary temperature regime in the spacecraft? You know that in the summer, when the sultry Sun shines, everyone wears light-colored clothes, in which the heat is less felt. What's the matter here? It turns out that a light surface, unlike a dark one, does not absorb radiant energy well. It reflects it and therefore heats up much weaker.
This property of bodies, depending on the color of the color, to a greater or lesser extent to absorb or reflect radiant energy, can be used to control the temperature inside the spacecraft. There are substances (they are called thermophototropes) that change their color depending on the heating temperature. As the temperature rises, they begin to discolor and the stronger, the higher the temperature of their heating. On the contrary, when cooled, they darken. This property of thermophototropes can be very useful if they are used in the thermal control system of spacecraft. After all, thermophototropes allow you to maintain the temperature of an object at a certain level automatically, without the use of any mechanisms, heaters or coolers. As a result, the thermal control system with the use of thermophototropes will have a small mass (and this is very important for spacecraft), and no energy will be required to put it into action. (Thermal control systems that operate without consuming energy are called passive.)
There are other passive thermal control systems. All of them have one important property - low weight. However, they are unreliable in operation, especially during long-term operation. Therefore, spacecraft are usually equipped with so-called active temperature control systems. A distinctive feature of such systems is the ability to change the mode of operation. An active temperature control system is like a radiator in a central heating system - if you want the room to be colder, you shut off the hot water supply to the radiator. On the contrary, if you need to raise the temperature in the room, the shut-off valve opens completely.
The task of the thermal control system is to maintain the air temperature in the ship's cabin within the normal, room temperature, i.e. 15 - 20 ° C. If the room is heated with central heating batteries, then the temperature in any place of the room is practically the same. Why is there a very small difference in air temperature near a hot battery and far from it? This is due to the fact that in the room there is a continuous mixing of warm and cold layers of air. Warm (light) air rises, cold (heavy) air sinks. This movement (convection) of air is due to the presence of gravity. Everything in a spaceship is weightless. Consequently, there can be no convection, i.e., air mixing and temperature equalization throughout the entire volume of the cabin. There is no natural convection, but it is created artificially.
For this purpose, the thermal control system provides for the installation of several fans. The fans, driven by an electric motor, force air to circulate continuously through the ship's cabin. Due to this, the heat generated by the human body or any device does not accumulate in one place, but is evenly distributed throughout the volume.
Rice. 11. Scheme of spacecraft cabin air cooling.
Practice has shown that more heat is always generated in a spacecraft than is radiated into the surrounding space through the walls. Therefore, it is advisable to install batteries in it, through which cold liquid must be pumped. This liquid will be given heat by the cabin air driven by the fan (see Fig. 11), while being cooled. Depending on the temperature of the liquid in the radiator, as well as its size, more or less heat can be removed and thus maintain the temperature inside the ship's cabin at the required level. The air-cooling radiator also serves another purpose. You know that when breathing, a person exhales a gas into the surrounding atmosphere, which contains much less oxygen than air, but more carbon dioxide and water vapor. If water vapor is not removed from the atmosphere, it will accumulate in it until a state of saturation occurs. Saturated steam will condense on all instruments, the walls of the ship, everything will become damp. Of course, in such conditions it is harmful for a person to live and work for a long time, and not all devices with such humidity can function normally.
The radiators we talked about help to remove excess water vapor from the atmosphere of the spacecraft cabin. Have you noticed what happens to a cold object brought from the street into a warm room in winter? It is immediately covered with tiny droplets of water. Where did they come from? Out of the air. Air always contains some amount of water vapor. At room temperature (+20°C), 1 m³ of air can contain up to 17 g of moisture in the form of steam. With an increase in air temperature, the possible moisture content also increases, and vice versa: with a decrease in temperature, less water vapor can be present in the air. That is why on cold objects brought into a warm room, moisture falls out in the form of dew.
In a spacecraft, the cold object is a radiator through which a cold liquid is pumped. As soon as too much water vapor accumulates in the cabin air, it from the air washing the radiator tubes condenses on them in the form of dew. Thus, the radiator serves not only as a means of cooling the air, but at the same time is its dehumidifier. Since the radiator performs two tasks at once - it cools and dries the air, it is called a refrigeration dryer.
So, in order to maintain normal temperature and air humidity in the spacecraft cabin, it is necessary to have a liquid in the thermal control system that must be continuously cooled, otherwise it will not be able to fulfill its role - to remove excess heat from the spacecraft cabin. How to cool the liquid? Cooling the liquid, of course, is not a problem if there is a conventional electric refrigerator. But electric refrigerators are not installed on spacecraft, and they are not needed there. Outer space differs from terrestrial conditions in that there is both heat and cold at the same time. It turns out that in order to cool the liquid, with the help of which the temperature and humidity of the air inside the cabin are maintained at a given level, it is enough to place it in outer space for a while, but in such a way that it is in the shade.
In the thermal control system, in addition to the fans that move the air, pumps are provided. Their task is to pump liquid from the radiator inside the cabin to the radiator installed on the outer side of the spacecraft shell, i.e. in outer space. These two radiators are connected to each other by pipelines, which have valves and sensors that measure the temperature of the liquid at the inlet and outlet of the radiators. Depending on the readings of these sensors, the rate of fluid transfer from one radiator to another is regulated, i.e., the amount of heat removed from the ship's cabin.
What properties should a fluid used in a temperature control system have? Since one of the radiators is located in outer space, where very low temperatures are possible, one of the main requirements for the liquid is a low solidification temperature. Indeed, if the liquid in the external radiator freezes, the temperature control system will fail.
Maintaining the temperature inside the spacecraft at a level at which human performance is maintained is a very important task. A person cannot live and work either in the cold or in the heat. Can a person exist without air? Of course not. Yes, and such a question never arises before us, since air on Earth is everywhere. The air fills the cabin of the spacecraft. Is there a difference in providing a person with air on Earth and in the cabin of a spacecraft? The airspace on Earth has a large volume. No matter how much we breathe, no matter how much oxygen we consume for other needs, its content in the air practically does not change.
The position in the cockpit of the spacecraft is different. Firstly, the volume of air in it is very small and, in addition, there is no natural regulator of the composition of the atmosphere, since there are no plants that would absorb carbon dioxide and release oxygen. Therefore, very soon people in the cabin of the spacecraft will begin to feel the lack of oxygen for breathing. A person feels normal if the atmosphere contains at least 19% oxygen. With less oxygen, it becomes difficult to breathe. In a spacecraft, one crew member has a free volume = 1.5 - 2.0 m³. Calculations show that already after 1.5 - 1.6 hours the air in the cabin becomes unsuitable for normal breathing.
Therefore, the spacecraft must be equipped with a system that would feed its atmosphere with oxygen. Where do you get oxygen from? Of course, it is possible to store oxygen on board the ship in the form of compressed gas in special cylinders. As needed, the gas from the cylinder can be released into the cabin. But this kind of oxygen storage is not very suitable for spacecraft. The fact is that metal cylinders, in which gas is under high pressure, weigh a lot. Therefore, this simple method of storing oxygen on spacecraft is not used. But gaseous oxygen can be turned into a liquid. The density of liquid oxygen is almost 1000 times greater than the density of gaseous oxygen, as a result of which much less capacity is required to store it (the same mass). In addition, liquid oxygen can be stored under slight pressure. Therefore, the walls of the vessel can be thin.
However, the use of liquid oxygen on board the ship is associated with some difficulties. It is very easy to supply oxygen to the atmosphere of the spacecraft cabin if it is in a gaseous state, it is more difficult if it is liquid. The liquid must first be turned into a gas, and for this it must be heated. Heating of oxygen is also necessary because its vapors can have a temperature close to the boiling point of oxygen, i.e. - 183°C. Such cold oxygen cannot be let into the cockpit, it is, of course, impossible to breathe it. It should be heated to at least 15 - 18°C.
Gasification of liquid oxygen and heating of vapors will require special devices, which will complicate the oxygen supply system. It must also be remembered that a person in the process of breathing not only consumes oxygen in the air, but simultaneously releases carbon dioxide. A person emits about 20 liters of carbon dioxide per hour. Carbon dioxide, as you know, is not a toxic substance, but it is difficult for a person to breathe air in which carbon dioxide contains more than 1 - 2%.
In order for the cabin air of a spacecraft to be breathable, it is necessary not only to add oxygen to it, but also to remove carbon dioxide from it at the same time. To do this, it would be convenient to have on board the spacecraft a substance that releases oxygen and at the same time absorbs carbon dioxide from the air. Such substances exist. You know that metal oxide is a combination of oxygen with a metal. Rust, for example, is iron oxide. Other metals are also oxidized, including alkali metals (sodium, potassium).
Alkali metals, combining with oxygen, form not only oxides, but also the so-called peroxides and superoxides. Peroxides and superoxides of alkali metals contain much more oxygen than oxides. The formula of sodium oxide is Na₂O, and the superoxide is NaO₂. Under the action of moisture, sodium superoxide decomposes with the release of pure oxygen and the formation of alkali: 4NaO₂ + 2Н₂О → 4NaOH + 3O₂.
Alkali metal superoxides proved to be very convenient substances for obtaining oxygen from them under spacecraft conditions and for cleaning cabin air from excess carbon dioxide. After all, alkali (NaOH), which is released during the decomposition of alkali metal superoxide, very readily combines with carbon dioxide. The calculation shows that for every 20 - 25 liters of oxygen released during the decomposition of sodium superoxide, soda alkali is formed in an amount sufficient to bind 20 liters of carbon dioxide.
The binding of carbon dioxide with alkali is that a chemical reaction occurs between them: CO₂ + 2NaOH → Na₂CO + H₂O. As a result of the reaction, sodium carbonate (soda) and water are formed. The ratio between oxygen and alkali, formed during the decomposition of alkali metal superoxides, turned out to be very favorable, since a person consumes an average of 25 A of oxygen per hour and releases 20 liters of carbon dioxide in the same time.
Alkali metal superoxide decomposes on contact with water. Where do you get water for this? It turns out you don't need to worry about it. We have already said that when a person breathes, he emits not only carbon dioxide, but also water vapor. The moisture contained in the exhaled air is sufficient in excess to decompose the required amount of superoxide. Of course, we know that oxygen consumption depends on the depth and frequency of breathing. You sit at the table and breathe calmly - you consume one amount of oxygen. And if you run or work physically, you breathe deeply and often, so you consume more oxygen than with calm breathing. Spacecraft crew members will also consume different amounts of oxygen at different times of the day. During sleep and rest, oxygen consumption is minimal, but when work related to movement is performed, oxygen consumption increases dramatically.
Due to the inhaled oxygen, certain oxidative processes occur in the body. As a result of these processes, water vapor and carbon dioxide are formed. If the body consumes more oxygen, it means that it emits more carbon dioxide and water vapor. Consequently, the body, as it were, automatically maintains the moisture content in the air in such an amount that is necessary for the decomposition of the corresponding amount of alkali metal superoxide.
Rice. 12. Scheme of replenishing the atmosphere of the spacecraft cabin with oxygen and cleaning it from carbon dioxide.
The scheme of air purification from carbon dioxide and its replenishment with oxygen is shown in Figure 12. Cabin air is driven by a fan through cartridges with sodium or potassium superoxide. From the cartridges, the air comes out already enriched with oxygen and purified from carbon dioxide.
A sensor is installed in the cabin that monitors the oxygen content in the air. If the sensor indicates that the oxygen content in the air is becoming too low, the fan motors are signaled to increase the number of revolutions, as a result of which the speed of air passing through the superoxide cartridges increases, and therefore the amount of moisture (which is in the air) that enters the cartridge at the same time. More moisture equals more oxygen. If the cabin air contains oxygen above the norm, then a signal is sent from the sensors to the fan motors to reduce the number of revolutions.
World Space Week kicked off today. It is held annually from 4 to 10 October. Exactly 60 years ago, the first man-made object, the Soviet Sputnik-1, was launched into low Earth orbit. It orbited the Earth for 92 days until it burned up in the atmosphere. After that, the road to space and man was opened. It became clear that it cannot be sent with a one-way ticket. Vladimir Seroukhov, correspondent of the MIR 24 TV channel, learned how space technologies developed.
In 1961, Saratov anti-aircraft gunners spotted an unidentified flying object on the radar. They were warned in advance: if they see such a container falling from the sky, it is not worth interfering with its flight. After all, this is the first space descent vehicle in history with a man on board. But landing in this capsule was not safe, so at an altitude of 7 kilometers he ejected and descended to the surface already with a parachute.
The capsule of the ship "Vostok", in the slang of engineers - "Ball", also descended by parachute. So Gagarin, Tereshkova and other space pioneers returned to Earth. Due to the design features, passengers experienced incredible overloads of 8 g. The conditions in Soyuz capsules are much easier. They have been used for more than half a century, but they should soon be replaced by a new generation of ships -.
“This is the seat of the crew commander and co-pilot. Just those places from which the ship will be controlled, control of all systems. In addition to these chairs, there will be two more chairs on the sides. This is for researchers,” says Oleg Kukin, Deputy Head of the Flight Test Department of RSC Energia.
Compared to the Soyuz family of ships, which are still morally obsolete, and where only three astronauts could fit in close quarters, the Federation capsule is a real apartment, 4 meters in diameter. Now the main task is to understand how convenient and functional the device will be for the crew.
Management is now available to two crew members. The remote control keeps pace with the times - these are three touch displays where you can control information and be more autonomous in orbit.
“Here, in order to choose a landing site where we can sit down. We directly see the map, the flight route. They can also control weather conditions if this information is transmitted from Earth, - said Oleg Kukin, Deputy Head of the Flight Test Department of RSC Energia.
"Federation" is designed for flights to the moon, it's about four days of travel one way. All this time, the astronauts must be in the fetal position. In rescue chairs, or cradles, it is surprisingly comfortable. Each one is a piece of jewelry.
"The measurement of all anthropometric data begins with the measurement of mass," said Victor Sinigin, head of the medical department of NPP Zvezda.
Here it is - the space studio, the Zvezda enterprise. Here, individual spacesuits and lodgements are made for astronauts. For people lighter than 50 kilograms, the way on board is ordered, as well as for those who are heavier than 95. Height must also be average in order to fit in the cabin of the ship. Therefore, measurements are taken in the fetal position.
This is how the chair for the Japanese astronaut Koichi Wakata was cast. Got an imprint of the pelvis, back and head. In conditions of weightlessness, the growth of any astronaut can increase by a couple of centimeters, so the lodgement is made with a margin. It should be not only comfortable, but also safe in case of a hard landing.
“The very idea of modeling is to save the internal organs. Kidneys, liver, they are encapsulated. If you give them the opportunity to expand, they can tear, like a plastic bag with water that has fallen to the floor,” Sinigin explained.
In total, 700 lodgements were made in this way not only for the Russians, but also for the Japanese, Italians and even colleagues from the States who worked at the Mir and ISS stations.
“The Americans on their Shuttle carried our lodgements and spacesuits that we made for them, and other rescue equipment. They left it all at the station, in case of an emergency leaving the station, but already on our ship, ”said Vladimir Maslennikov, lead engineer of the testing department at NPP Zvezda.
The spacecraft resembles a submarine: here and there the crew is forced to live in a pressurized cabin, completely isolated from the external environment. The composition, pressure, temperature and humidity of the air inside the cabin will be regulated by a special apparatus. But the advantage of a spacecraft over a submarine is the smaller difference between the pressure inside the cabin and outside. And the smaller this difference, the thinner the walls of the case can be.
The sun's rays can be used to heat and illuminate the ship's cabin. The skin of the ship, like the earth's atmosphere, delays the ultraviolet rays of the Sun penetrating interplanetary space, which are harmful to the human body in large quantities. For better protection during collisions with meteoric bodies, it is advisable to make the ship's skin multilayered.
The design of a spacecraft depends on its purpose. A ship to land on the moon will be very different from a ship designed to fly around it; a ship to Mars must be built differently from a ship to Venus; a rocket ship powered by thermochemical fuel will be significantly different from a nuclear ship.
The spacecraft on thermochemical fuel, designed to fly to an artificial satellite, will be a multi-stage rocket the size of an airship. At launch, such a rocket should weigh several hundred tons, and its payload is about a hundred times less. Tightly adjacent stages will be enclosed in a streamlined body to better overcome air resistance when flying in the atmosphere. A relatively small cabin for the crew and a cabin for the rest of the payload will apparently be located in the bow of the ship. Since the crew will have to spend only a short time on board such a ship (less than an hour), there will be no need for complex equipment, which will be equipped with interplanetary ships designed for a long flight. Flight control and all measurements will be carried out automatically.
The spent stages of the rocket can be lowered back to Earth either by parachute or with the help of retractable wings that turn the stage into a glider.
Consider another version of the spacecraft (see Fig. 8, center, on pages 24-25). The ship will go from an artificial satellite into flight around the moon for a long survey of its surface without landing. After completing the task, he will return directly to Earth. As you can see, this ship consists mainly of two twin rockets with three pairs of cylindrical tanks filled with fuel and oxidizer, and two space gliders with retractable wings designed to descend to the Earth's surface. The ship does not need a streamlined skin, since the launch is made outside the atmosphere.
Such a ship will be completely built and tested on Earth, and then transferred to the interplanetary station disassembled. Fuel, equipment, food supplies and oxygen for breathing will be delivered there in separate batches.
After the ship is assembled at the interplanetary station, it will go further into world space.
Fuel and oxidizer will enter the engine from the central cylindrical tanks, which are the main cabins of the spacecraft, temporarily filled with fuel. They are emptied a few minutes after takeoff. Temporarily the crew is located in a less comfortable glider cockpit.
It is enough to open a small valve connecting the tanks with airless space, so that the remaining fuel instantly evaporates. Then the cockpit tanks are filled with air, and the crew enters them from the glider; here the astronauts will spend the rest of the flight.
Having flown to the Moon, the ship turns into its artificial satellite. For this, fuel and an oxidizer located in the rear side tanks are used. After using the fuel, the tanks are unhooked. When on -
The return time will come and the engine will be turned on. Fuel for this purpose is stored in the front side tanks. Before diving into the Earth's atmosphere, the crew transfers to space gliders, which are unhooked from the rest of the ship, which continues to circle the Earth. The glider enters the Earth's atmosphere and, maneuvering retractable wings, descends.
When flying with the engine off, people and objects on the ship will be weightless. This presents a great inconvenience. Designers may have to create artificial gravity on board the ship.
The ship shown in Fig. 8 is built exactly on this principle. Its two components, taking off as a whole, are then separated from each other, remaining, however, connected by cables, and with the help of small rocket engines are driven in a circular motion around a common center of gravity (Fig. 6). After the required rotation speed is reached, the motors are turned off and the movement continues by inertia. The centrifugal force that arises in this case, according to the idea of Tsiolkovsky, should replace the travel
A spacecraft used for flights in near-Earth orbit, including under human control.
All spacecraft can be divided into two classes: manned and launched in control mode from the Earth's surface.
In the early 20s. 20th century K. E. Tsiolkovsky once again predicts the future exploration of outer space by earthlings. In his work "Spaceship" there is a mention of the so-called celestial ships, the main purpose of which is the implementation of human spaceflight.
The first spaceships of the Vostok series were created under the strict guidance of the general designer of OKB-1 (now the Rocket and Space Corporation Energia) S.P. Korolev. The first manned spacecraft "Vostok" was able to deliver a man into outer space on April 12, 1961. This cosmonaut was Yu. A. Gagarin.
The main objectives of the experiment were:
1) study of the impact of orbital flight conditions on a person, including his performance;
2) verification of the principles of spacecraft design;
3) development of structures and systems in real conditions.
The total mass of the ship was 4.7 tons, diameter - 2.4 m, length - 4.4 m. Among the on-board systems with which the ship was equipped, the following can be distinguished: control systems (automatic and manual modes); system of automatic orientation to the Sun and manual - to the Earth; life supporting system; thermal control system; landing system.
In the future, the developments obtained during the implementation of the Vostok spacecraft program made it possible to create much more advanced ones. To date, the "armada" of spacecraft is very clearly represented by the American reusable transport spacecraft "Shuttle", or Space Shuttle.
It is impossible not to mention the Soviet development, which is currently not used, but could seriously compete with the American ship.
Buran was the name of the Soviet Union's program to create a reusable space system. Work on the Buran program began in connection with the need to create a reusable space system as a means of deterring a potential adversary in connection with the start of the American project in January 1971.
To implement the project, NPO Molniya was created. In the shortest possible time in 1984, with the support of more than a thousand enterprises from all over the Soviet Union, the first full-scale copy was created with the following technical characteristics: its length was more than 36 m with a wingspan of 24 m; starting weight - more than 100 tons with a payload weight of up to
30 tons
"Buran" had a pressurized cabin in the nose compartment, which could accommodate about ten people and most of the equipment for flight in orbit, descent and landing. The ship was equipped with two groups of engines at the end of the tail section and in front of the hull for maneuvering, for the first time a combined propulsion system was used, which included fuel tanks for oxidizer and fuel, temperature control of pressurization, fluid intake in zero gravity, control system equipment, etc.
The first and only flight of the Buran spacecraft was made on November 15, 1988 in an unmanned, fully automatic mode (for reference: the Shuttle still only lands on manual control). Unfortunately, the flight of the ship coincided with the difficult times that began in the country, and due to the end of the Cold War and the lack of sufficient funds, the Buran program was closed.
The start of a series of American spacecraft of the "Shuttle" type was laid in 1972, although it was preceded by a project of a reusable two-stage aircraft, each stage of which was similar to a jet.
The first stage served as an accelerator, which, after entering orbit, completed its part of the task and returned to Earth with the crew, and the second stage was an orbital ship and, after completing the program, also returned to the launch site. It was the time of an arms race, and the creation of a ship of this type was considered the main link in this race.
To launch the ship, the Americans use an accelerator and the ship's own engine, the fuel for which is placed in an external fuel tank. Spent boosters after landing are not reused, with a limited number of launches. Structurally, the ship of the Shuttle series consists of several main elements: the Orbiter aerospace plane, reusable rocket boosters and a fuel tank (disposable).
Due to a large number of shortcomings and design changes, the first flight of the spacecraft took place only in 1981. In the period from April 1981 to July 1982, a series of orbital flight tests of the Columbia spacecraft was carried out in all flight modes. Unfortunately, in a series of flights of the Shuttle series, there were tragedies.
In 1986, during the 25th launch of the Challenger, a fuel tank exploded due to an imperfect design of the apparatus, as a result of which all seven crew members died. Only in 1988, after a number of changes were made to the flight program, the Discovery spacecraft was launched. To replace the Challenger, a new ship, the Endeavor, was put into operation, which has been operating since 1992.
