Interesting to see how different people solve the same problem. Everyone has their experience, their initial conditions, but when the purpose and requirements are similar, this task is functionally similar to each other, although they may differ in the specific implementation. In the late 50s and the Soviet Union and the United States began to develop a manned spacecraft for the first steps into space. The requirements were similar - one man crew, while in space - up to several days. But here's the machine receives a different and, I think, it would be interesting to compare them.
Introduction h4> Neither the Soviet Union nor the United States did not know what awaits man in space. Yes, in flight on an airplane can be played weightlessness, but lasting only about 30 seconds. What will happen to a person with prolonged weightlessness? Doctors frightening inability to breathe, drink, see (supposedly eye should lose its shape due to incorrect operation of the eye muscles), to think (frightened madness or loss of consciousness). Knowledge of high-energy cosmic particles leads to the idea of radiation injuries (and even after the fly regularly in newspapers surfaced creepy version of radiation sickness flew astronauts). Therefore, the first ships were designed for a small time spent in space. First flight duration measured in minutes, the next - for hours, or turns around the Earth (one turn - about 45 minutes).
Tools excretion h4> The main factor influencing the design of the ship was carrying capacity of the launch vehicle. And two-stage R-7, and "Atlas" could get into low Earth orbit approximately 1300 kg. But for the "Seven" had to work in the lunar launches in 1959 the third stage - the block "E", increasing load capacity three-stage rocket to 4, 5 tons. And the US still could not work out the basic two-step "Atlas" and the first theoretically possible option "Atlas-Agena" flew only in the early 1960s. The result is an anecdote - Soviet "Vostok" weighed 4, 5 tons, and the weight of "Mercury" was comparable to the mass of the "Sputnik 3" - 1300 kg.
Exterior design elements h4> We first consider the exterior of a ship:
«East» i>
«Mercury» i>
Case form h5> «Vostok" on ascent was under resettable fairing. Therefore, the designers did not care aerodynamic shape of a ship, and you can safely place the antenna, balloons, blinds thermoregulation and other fragile items on the surface of the device. A particular design of block "E" to determine the characteristic conical "tail" of the ship.
"Mercury" also could not afford to drag to orbit heavy cowl. Therefore, the ship had an aerodynamic tapered, and all types of sensors have been retractable periscope.
Thermal protection h5> When you create the "East" designers started from solutions that provide maximum reliability. Therefore, the shape of the landing vehicle chosen as a ball. Uneven weight distribution effect "Vanka-Vstanka" when the lander on their own, without any control, in the right position. A heat shield was applied to the entire surface of the lander. When braking on reentry impact with the ball surface was uneven, so the thermal protection layer has a different thickness.
Left: flow past a sphere at hypersonic speed (wind tunnel), right: unevenly charred lander "Vostok-1». I>
The conical shape of "Mercury" meant that the heat shield is required only from the bottom. On the one hand, it saves weight, on the other hand, incorrect orientation of the ship at the entrance to the dense layers of the atmosphere has a high probability of its destruction. On the upper part of the ship was a special aerodynamic spoiler which had to turn the "Mercury" astern.
Left: cone at hypersonic speeds in the wind tunnel, right: thermal protection "Mercury" after landing. I>
Curiously, the thermal protection material was similar - to the "East" resin impregnated asbestos cloth on "Mercury" - fiberglass and rubber. In both cases, with a filler material tkanepodnobny burned layers and filler evaporate, creating an extra layer of thermal protection.
Brakes h5> Brake motor "East" was laminated. From a security perspective it was not a very good solution. Yes, the "East" were launched so that during the week slow down the natural way of atmosphere, but, firstly, in the flight of Gagarin's orbit was calculated above that actually "turn off" this backup system, and secondly, the natural braking meant land anywhere between 65 degrees north latitude to 65 degrees south latitude. The reason for this constructive - two LRE does not fit into the vehicle, and then the solid motors were not disbursed. Reliability TDU increases the maximum design simplicity. There were times when TDU gave slightly less momentum than necessary, but complete failure was not even once.
TDU «East» i>
On the "Mercury" for a thermal shield was the engine block separation and braking. Both engines were established in triplicate for greater reliability. Engines division turned on immediately after turning off the engine of the launch vehicle to the ship moved away from the launch vehicle to a safe distance. Brake motors are switched to de-orbit. To return from orbit, it was only one actuated brake motor. Engine block was mounted on a steel tape and resets after braking.
TDU «Mercury» i>
Landing System h5> On the "East" pilot sat separately from the vehicle. At an altitude of 7 km cosmonaut ejected and sat alone on a parachute. For greater reliability, the parachute system was dubbed.
On the "Mercury" used the idea of landing on water. Water softens the blow, and a large fleet of US not have trouble finding the capsule in the ocean. To soften the blow of water discloses special air-bag shock absorber.
History has shown that planting systems were the most dangerous in the projects. Gagarin almost got into the Volga, Titov landed next to the train, Popovich has broken almost on the rocks. Grissom nearly drowned with the ship, and Carpenter searched for more than an hour and already started to count the dead. The following ships were no bailout pilot nor pillows-absorber.
emergency rescue system h5> Established ejection system astronaut on the "East" could work as a rescue system in the initial phase. In the fairing was a hole for planting astronaut and emergency bailout. Parachute could not manage to open in case of an accident in the first seconds of flight, so right from the start of the table was stretched mesh, which was supposed to cushion the fall.
The grid at the bottom of the foreground i>
At high altitude ship was to separate from the rocket, using standard tools division.
On the "Mercury" was emergency rescue system, which was supposed to lead the capsule from the destructive missiles from the start to the end of the dense layers of the atmosphere.
In the event of an accident at high altitude use standard separation system.
Ejection seats as a rescue system used to "Gemini", and also a test flight "Space Shuttle". SAS-style "Mercury" was on "Apollo" and still be put to the "Union».
Engines orientation h5> as a working body for orientation on the ship "Vostok" use compressed nitrogen. The main advantage of the system was easy - the gas contained in the balloon and the balloon was manufactured using a simple system.
On the ship "Mercury" was used catalytic decomposition of concentrated hydrogen peroxide. In terms of specific impulse is more profitable compressed gas, but reserves the working medium on "Mercury" were extremely small. Actively maneuvering, could spend the entire stock of peroxide in less than one turn. But its stock had to be retained for operations targeting landing ... Astronauts secretly competed among themselves who will spend less peroxide and involved for photo Carpenter got into serious trouble - he wastefully spent working body orientation and peroxide ended during landing. Fortunately, the height was about 20 km and the disaster did not happen.
Later peroxide as the working fluid used in the first "Union" and then all went to the high boiling components UDMH / AT.
thermoregulatory system h5> On the "East" used blinds that you opened, increasing the radiating area of the ship, then closed.
On the "Mercury" was a system that uses water evaporation in a vacuum. It was smaller and lighter, but the problem with it was more like, in flight Cooper she knew only two states - "hot" and "cold».
The internal design elements h4> The internal layout of the "Vostok»:
Internal layout of the ship "Mercury»:
Toolbar h5> Toolbars most clearly show the difference in design approaches. "East" did the designers of missiles, so its toolbar differs minimum controls:
Photo i>
The left pane. I>
The main panel. I>
"Mercury" as did former aircraft engineers, and astronauts have made efforts to ensure that the cabin was familiar to them. Therefore, the controls are much more:
Photo. I>
The scheme. I>
At the same time, the similarity of problems generated identical devices. And on the "East" and "Mercury" was a globe with a clockwork mechanism, showing the current position of the vehicle and the estimated landing spot. And on the "East" and "Mercury" were indicators phases of flight - on "Mercury" is the "Flight Operations Management" in the left pane, on the "East" - indicators of "Descent-1", "Descent 2", "Spusk- 3 "and" Prepare to bail "on the front panel. Both ships had a system of manual orientation:
«gaze" to "East". If the peripheral part of the horizon on all sides, and in the center of the Earth is moving from bottom to top, the orientation of the braking right. I>
Periscope on "Mercury". The marks show the correct orientation of the braking. I>
Life support system h5> On both ships produced in flight suits. In the "East" maintain an atmosphere close to the earth - the pressure of 1 atm, the air oxygen and nitrogen. On the "Mercury" to save weight the atmosphere was pure oxygen at reduced pressure. This adds inconvenience - the astronaut had to be about two hours before starting to breathe in oxygen ship, during injection needed to pit atmosphere of the capsule, and then block the ventilation valve, and landing again open it to increase the pressure with atmospheric.
Sanitary system was more advanced on the "East" - flying several days had the opportunity to meet the needs of large and small. On the "Mercury" were only urinals, from large hygienic problems saved a special diet.
Electrical h5> Both ships used on battery power. "East" were povynoslivee on "Mercury" daily flight Cooper ends in failure conditions, a good half of the instrument.
Conclusion h4> Both ships were the peak of the art of their countries. Being the first, both types were as good decisions and bad. Ideas of the "Mercury" live in the rescue system and conical capsules and grandchildren "East" still fly - "Photons" and "Bion" use the same spherical landers:
In general, the "East" and "Mercury" were a good ship, will make the first steps into space, and avoid fatal accidents.
Source: habrahabr.ru/post/230445/
