Spaceships today called phones started to deliver astronauts to low-Earth orbit and then return them to Earth. It is understood that the technical requirements for the spacecraft more stringent than any other spacecraft. flight conditions (overload, temperature, pressure, etc.) must be maintained for them very precisely in order not to endanger the life of man. The ship, which for a few hours or even days getting home to the astronaut, normal human conditions must be created - the astronaut must breathe, drink, eat, sleep, send natural needs. He should be able to deploy the ship during the flight, at its discretion and to change orbit, ie the ship during its motion in space should easily be reoriented and manipulated. the spacecraft must repay all the tremendous speed that told him at the start of the carrier rocket to return to earth. If the Earth had no atmosphere, it would have to spend the same amount of fuel, how much was spent during the ascent into space. Fortunately, this is not necessary if the landing exercise on a very flat trajectory, gradually sinking into the dense layers of the atmosphere, it is possible to slow down the vehicle on the air with a minimum of fuel. As the Soviet "Vostok" and the US "Mercury" was carried out land in this way and this explains many of the characteristics of their design. Since a significant part of the energy during braking is to heat the ship, he simply burned without a good thermal protection it is burned in the atmosphere most of the meteorites and ends its existence satellites. Therefore it is necessary to protect ships bulky heat-resistant heat-shielding shells. (For example, in the Soviet "East" her weight was 800 kg -. One third of the weight of the lander) Wanting to lighten the ship as possible, the designers have implemented this screen is not the whole ship, and only the body of the descent capsule. Thus, from the outset established structure being divided ship (it was tested on the "East", and then became a classic for all Soviet and many American spacecraft). The ship is as if two independent parts: the instrument compartment and lander (the latter is used in astronaut flight cabin).
The first Soviet spacecraft "Vostok" with a total weight of 4 tons 73 put into the orbit by using a three-stage carrier rocket of the same name. The total mass of the space launching complex was 287 tons Constructive "East" consisted of two main sections:. Lander and instrument compartment. Lander with astronaut cabin was made in the form of a sphere diameter of 2 m 3 and had a weight of 2, 4 m.
Sealed enclosure was made of aluminum alloy. Inside lander designers sought to locate only those systems and ship devices that were needed during the flight, or those that are directly used by the astronaut. All the rest were made in the instrument compartment. Inside the cabin housed the ejection seat astronaut. (In case you would have to eject at the start, the chair is provided with two solid propellant boosters.) There were also remote control, food and water. The life support system was designed to operate for ten days. The astronaut had during the flight to be in an airtight suit, but with an open helmet (this helmet automatically close in the event of sudden depressurization of the cabin).
Internal free volume lander was 1, 6 cubic meters. Necessary conditions in the cockpit of the spacecraft maintained two automatic system: life-support system and thermal control system. As you know, people in the process of life consumes oxygen, releases carbon dioxide, heat and moisture. The two systems just provide the absorption of carbon dioxide, oxygen replenishment, selection of the air excess moisture and heat removal. In the cockpit, "the East" maintained usual in the world state of the atmosphere at a pressure 735-775 mm Hg. Art. and 20-25% oxygen content. The unit temperature control system is partly reminiscent of air conditioning. It contained an air-liquid heat exchanger, a coil which flowed chilled fluid (coolant). Fan forced through the heat exchanger is warm and humid air cabin, which is cooled on its cold surfaces. Wherein condensed moisture. The cooling done in the descent module of the instrument compartment. Absorb the warm liquid is forced pump was run through the radiator, radiator located on the outer conical shell instrument compartment. coolant temperature is automatically maintained in the desired range with special shutters that covered the radiator. Shutters blinds can be opened or closed by changing the heat flows emitted by the radiator. To maintain the desired composition of the air in the cabin there was a lander regenerative device. cabin air when the fan is continuously flowed through special replaceable cartridge containing superoxide alkali metals. These substances (eg, K2O4) can effectively absorb carbon dioxide and release oxygen while. The operation of the entire automation supervised onboard software device. The inclusion of different systems and devices are produced as by commands from the Earth, and by the astronaut. On the "East" had a whole range of radio, and makes it possible to maintain two-way communication, to make various measurements, to administer the ship from Earth and much more. With the help of the transmitter "Signal" is constantly receiving information sensors placed on the body of the astronaut, regarding his state of health. The basis of the power supply system were silver-oxide battery: the main battery is housed in the instrument compartment, and more, providing power to the descent - in the descent module.
Instrument compartment had a mass of 2, 27 m. Close to its junction with the lander were 16 spherical tanks with compressed nitrogen reserves for micromotors orientation and oxygen for life support systems. It is very important in any spaceship playing a system of orientation and motion control. On the "East," it included several subsystems. The first of them - navigation - consisted of a series of position sensors of the spacecraft in space (including the Sun sensor, gyro sensor, an optical device "gaze" and others). The signals received from the sensors to the control system that can operate automatically or with the participation of the astronaut. On the panel there was a cosmonaut handle manual control of the spacecraft orientation. Deployment of the ship took place with the help of a set arranged in a certain way a small jet nozzles, in which a balloon compressed nitrogen. In total, the instrument compartment there were two sets of nozzles (eight in all), which could be connected to the three groups of cylinders. The main task, which is solved with the help of these nozzles was that, in order to properly orient the ship before applying the brake pulse. This is required to do in a particular direction and at a fixed time. The error here is not tolerated.
Brake propulsion system with traction 15 kN 8 was in the bottom of the compartment. It consisted of an engine, fuel tanks and fuel supply system. Time of its work was 45 seconds. Before return to Earth brake propulsion system oriented so that the brake pulse to about 100 m / s. It was enough to go on the descent trajectory. (At 180-240 km altitude orbit it was calculated in such a way that even in case of failure of brake installation ship in ten days would still have entered the dense layers of the atmosphere. It is in this period and was calculated oxygen supply, drinking water, food, battery charge .) Then there is a separation of the descent capsule of the instrument compartment. Further deceleration of the ship was no longer due to atmospheric drag. This overload reached 10 g, then there astronaut weight increased ten times.
The speed of the descent capsule in the atmosphere decreased to 150-200 m / s. But to ensure a safe landing in contact with the ground, the speed should not exceed 10 m / s. Excess speed quenched by parachutes. They revealed gradually: first extract, then - the brake, and finally the main. At an altitude of 7 km cosmonaut had to eject and land separately from the lander at a speed of 5-6 m / s. This was done with the help of catapult seats, which are installed on special guides and shoots from the lander after the separation of the hatch cover. It also was revealed first drogue parachute seat, and at an altitude of 4 km (at a speed of 70-80 m / s) astronaut detachable from the chair and continue down on its own parachute.
Work in preparation for a manned flight to CB Queen began in 1958. The first launch of the "East" in the unmanned mode was made May 15, 1960. Due to the malfunction of one of the sensors before switching on the brake propulsion ship it was properly focused and, instead of lowered, moved to a higher orbit. The second run (23 July 1960) was even less successful - at the beginning of the flight accident occurred. The lander separated from the vehicle and collapsed in the fall. To avoid this danger on all these ships had introduced a system of emergency rescue. But the third launch of the "East" (August 19-20, 1960) was quite successful - on the second day of the lander with all experimental animals: mice, rats, and two dogs - Belka and Strelka - safely landed in a given area. It was the first case in the history of space exploration beings return to Earth after the space flight. But the next flight (1 December 1960) once again had an unfortunate outcome. The ship went into space and complete the entire program. the team was fed through the night to return to the ground. However, due to failure of the braking propulsion descent capsule entered the atmosphere with extremely high speed and burned. With him died the experimental dogs Pchelka and Mushka. During the launch of 22 December 1960 there was a failure of the last stage, but emergency rescue system worked properly way - lander landed without damage. Only six (9 March 1961) and seventh (25 March 1961) starts the "East" passed quite safely. Having made one revolution around the Earth, both ships returned safely to Earth with all experimental animals. These are two completely simulated flight the next manned flight, so that even in the chair was a special mannequin. The first in the history of manned space flight took place, as you know, April 12, 1961. Soviet cosmonaut Yuri Gagarin, aboard the "Vostok-1" makes one revolution around the Earth, and on the same day returned safely to Earth (the entire flight lasted 108 minutes). Since the era of manned flights was opened.
In the US preparation for manned flight on the "Mercury" program also began in 1958. First unmanned flights were carried out, and then fly on a ballistic trajectory. The first two launches "Mercury" on a ballistic trajectory (in May and July 1961) were carried out with the help of a rocket "Redstone" and the following conclusions into orbit by carrier rocket "Atlas-D». February 20, 1962 US astronaut John Glenn on «Mercury-6" made its first orbital flight around the Earth.
The first US spacecraft was significantly less than the Soviet. Carrier rocket "Atlas-D» with a starting weight of 111, 3 tons has been able to launch the load no more than 1 35 tonnes. Therefore, the ship "Mercury" was designed with an extremely severe restrictions on weight and dimensions. The basis of the ship was returned to the capsule of the Earth. It had frusto-conical shape with a spherical bottom and a cylindrical upper portion. Based housed cone braking system of the three jets of solid 4, 5 kN and an operating time of 10 seconds. During the descent capsule entered the Earth's atmosphere head forward. Therefore, a heavy heat shield only located here. In front of the cylindrical portion of the antenna was located and parachute section. Parachutes were three: the brake, main and reserve, which pushes with the help of the air.
Inside the cockpit there was a free space 1, 1 cubic meter. Astronaut wearing a hermetic suit, he settled in the chair. Before him were the window and control panel. The farm was placed over the ship gunpowder engine SAS. The life support system on the "Mercury" was significantly different from the one that was on the "East". Inside the ship created a pure oxygen atmosphere with a pressure of 228-289 mm Hg. Art. As the consumption of oxygen cylinders supplied in the cabin and an astronaut suit. To remove the carbon dioxide system was used with lithium hydroxide. The suit was cooled oxygen, which before used for breathing, was fed to the lower part of the body. The temperature and humidity were maintained by an evaporative type heat exchangers - going moisture with a sponge which periodically push-ups (it turned out that under weightless conditions this method was not suitable, so it was only used on the first ship). Energy was provided batteries. The entire life-support system has been designed only for 1 to 5 days. To control the orientation of the "Mercury" had managed 18 Engines operating on monopropellant - hydrogen peroxide. Astronaut splashed down with the ship on the ocean surface. The capsule had an unsatisfactory buoyancy, so just in case it had on an inflatable raft.