Why are rockets made multistage? Multistage rockets and rocket-space systems What are multistage rockets?
Owners of patent RU 2532289:
The invention relates to space technology and can be used in single-stage launch vehicles. A single-stage heavy-class launch vehicle contains a propulsion system with one or more oxygen-hydrogen rocket engines, a fuel tank (TF), one or two detachable additional fuel tank(DTB), installed in a tandem configuration, one or several pairs of diametrically opposed detachable mounted fuel tanks (NTB), spacer, pipelines connecting the TB to the DTB and NTB. The invention makes it possible to eliminate the fall fields of spent fuel tanks. 8 ill.
The invention relates to the design of launch vehicles and can be used in the development of single-stage launch vehicles for launching payloads into orbit of an artificial Earth satellite (AES).
It should be noted that in order to achieve orbital speed, a single-stage launch vehicle theoretically needs to have a final mass of no more than 7-10% of the starting mass, which, even with existing technologies, makes them difficult to implement and economically ineffective due to the low mass of the payload. In the history of world cosmonautics, single-stage launch vehicles were practically never created - only the so-called ones existed. one-and-a-half-stage modifications (for example, the American Atlas launch vehicle with discardable additional propulsion engines). The presence of several stages makes it possible to significantly increase the ratio of the payload mass to the initial mass of the rocket. At the same time, multi-stage launch vehicles require the presence of territories for the fall of intermediate stages (Material from Wikipedia - the free encyclopedia).
The single-stage launch vehicle VR-190 is known, presented in the book by V.N. Kobelev and A.G. Milovanov “Spacecraft Launch Vehicles,” 2009 (Chapter 5, p. 134).
The VR-190 launch vehicle was designed for vertical flight to an altitude of up to 200 km.
The fundamental disadvantage of the VR-190 launch vehicle was the inability to launch a payload into satellite orbit.
Modern work in the field of launch vehicles, based on the use of oxygen-hydrogen liquid rocket engines (LPRE), has shown the beneficial effect of cryogenic fuel on the main characteristics of the launch vehicle.
An example is the Delta-4 launch vehicle (Boeing, USA), the first stage of which, according to theoretical calculations, can launch payloads into satellite orbit without using the second stage and, thus, fulfill the role of single stage rocket-carrier, although the payload will be small (Cosmonautics News. Vol. 13, No. 1 (240), 2003, p. 46).
The purpose of the invention is to eliminate this drawback.
This goal is achieved by the fact that a single-stage launch vehicle (Fig. 1, 2), consisting of a propulsion system with one or more oxygen-hydrogen rocket engines 1 and a fuel tank 2, is equipped with one or two additional fuel tanks 3, which are tandem (longitudinal) ) scheme are sequentially located on the fuel tank 2 using a spacer 4, inside of which the payload 5 is installed and, in addition, the launch vehicle according to a batch (parallel) scheme is equipped with one or several pairs of mounted diametrically opposite fuel tanks 6, located relative to each other, with In this case, fuel tanks 7 and 8 and oxidizer 9 and 10, fuel tanks 3 and 6, respectively, are connected by pipelines 11, 12 and 13, 14 with fuel tanks 15 and oxidizer 16 of the fuel tank of launch vehicle 2.
During the operation of the propulsion system 1 and the intake of fuel from the fuel tanks 15 and oxidizer 16 of the fuel tank of the launch vehicle 2, fuel is simultaneously supplied to these tanks, respectively, from the fuel tanks 8 and oxidizer 10 of the first pair of mounted tanks 6, diametrically opposed to each other.
After the fuel has been exhausted from the first pair of mounted fuel tanks, they are separated and the fuel (Fig. 3, 4) and oxidizer are simultaneously taken from the next pair of mounted fuel tanks.
After separation of the last pair of mounted fuel tanks, the single-stage launch vehicle uses fuel from fuel tank 3 (Figs. 5, 6).
After fuel is exhausted from tank 3, the single-stage launch vehicle uses fuel from its own fuel tank 2 until the satellite enters orbit with further separation of tank 3 (Figs. 7, 8).
The technical result of the invention, based on the use of additional fuel tanks in tandem and package configurations, located on the fuel tank of the launch vehicle and discarded during the flight, is the creation of a new class of environmentally friendly single-stage heavy-class launch vehicles capable of delivering a payload into satellite orbit and being economical and reliable transport system. At the same time, the range and number of expensive liquid-propellant rocket engines used in a single-stage launch vehicle are reduced and the problem of choosing the launch site of the launch vehicle and impact fields is practically eliminated, since mounted fuel tanks are made of aluminum alloys and other materials that burn in the Earth’s atmosphere.
A single-stage heavy-class launch vehicle, consisting of a propulsion system with one or more oxygen-hydrogen liquid rocket engines and a fuel tank, characterized in that the single-stage launch vehicle is equipped with one or two additional fuel tanks, which are sequentially arranged in a tandem (longitudinal) pattern on the fuel tank of the launch vehicle using a spacer, and, in addition, the launch vehicle is equipped in a batch (parallel) configuration with one or several pairs of fuel tanks diametrically opposed to each other, while the fuel and oxidizer tanks of the additional fuel tanks are connected by pipelines to the tanks fuel and oxidizer of the fuel tank of a single-stage launch vehicle, while the side mounted fuel tanks are installed with the possibility of their separation after the fuel is exhausted, additional tanks - with the possibility of separation.
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The invention relates to astronautics, namely to tanks for storing rocket fuel components. Space launcher contains a cryogenic tank containing a shell, one partition (limiting the upper and lower volumes of the fluid medium) with a central opening (connecting the upper and lower volumes of the fluid medium), a ventilation duct with a housing, a retaining barrier (wall) or mechanical limiter, and passages in the partition.
The invention relates to composite materials intended for use in space. The use of at least one polymerizable resin R1 selected from the group consisting of epoxidized polybutadiene resins and characterized in the unpolymerized state: - a total mass loss (TML) value less than 10%, a recovered mass loss (RML) value less than 10%, and the amount of collected volatile condensable material (VCM).
The invention relates to space technology, namely to the layout of spacecraft. The container is made with three holes for steam removal, the main hole is made with a center through which the central axis of the container passes, parallel to the longitudinal axis of the satellite, directed towards the center of mass of the satellite, two additional holes are made with centers through which another parallel axis of the container passes, parallel the axis of the satellite, directed in the direction of its flight.
The invention relates to equipment of spacecraft (SV) and, in particular, to their power propulsion systems. The spacecraft electrolysis installation includes a solid polymer electrolyzer connected to the spacecraft power supply system and a water supply system.
The invention relates to winged aircraft that use cryogenic fuel, and concerns reusable rocket units. Glider aircraft includes a body with a cryogenic cylindrical tank, a wing, and wing fastening elements.
The group of inventions relates to the design of parts and elements of an aircraft, mainly to the design of the aft part space plane(KS), as well as methods for correcting the trajectory and optimizing the thrust of the KS rocket engine.
The invention relates to rocket and space technology, cryogenic technology and concerns pneumohydraulic connection of mating objects. The pneumohydraulic connection protection device contains a casing that is installed on the connection and is equipped with a fitting with a plug.
The invention relates to rocket technology, namely to single-stage launch vehicles. A single-stage launch vehicle contains one or more liquid rocket engines, a fuel tank with fuel and oxidizer tanks, one or several pairs of mounted fuel and oxidizer fuel tanks connected, respectively, to the fuel and oxidizer tanks of the fuel tank.
The invention relates to space technology and can be used in single-stage launch vehicles. A single-stage heavy-class launch vehicle contains a propulsion system with one or more oxygen-hydrogen rocket engines, a fuel tank, one or two detachable additional fuel tanks installed in a tandem configuration, one or several pairs of diametrically opposed detachable mounted fuel tanks, a spacer, and pipelines connecting TB with DTB and NTB. The invention makes it possible to eliminate the fall fields of spent fuel tanks. 8 ill.
If the rocket accelerates for a long enough time - so that the astronauts do not experience excessive overload - the gas escaping from the nozzle transfers momentum not only to the shell, but also to the huge supply of fuel that the rocket continues to “carry with it.” Since the mass of fuel is much more mass shell, the rocket accelerates much more slowly than if all the fuel were ejected at once. Calculations show that in order for a rocket to reach escape velocity and launch an artificial satellite into low-Earth orbit, the mass of fuel must be tens of times greater than the mass of the payload. To reduce the mass of the “accelerated” part of the rocket, the rocket is made multi-stage .
The first and second stages are containers with fuel, combustion chambers and nozzles. Once the fuel contained in the first stage is burned, that stage separates from the rocket, causing the rocket's mass to be significantly reduced. The second stage engines immediately turn on and operate until the fuel contained in the second stage runs out. Finally, this stage is also discarded, and then the third stage engines are turned on, completing the acceleration of the rocket to its design speed.
Mechanics. 2014
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What is the device multistage rocket Let's look at the classic example of a rocket for space flight, described in the works of Tsiolkovsky, the founder of rocket science. It was he who was the first to publish the fundamental idea of manufacturing a multi-stage rocket.
The principle of operation of the rocket.
In order to overcome gravity, a rocket needs a large supply of fuel, and the more fuel we take, the greater the mass of the rocket. Therefore, to reduce the mass of the rocket, they are built on the multi-stage principle. Each stage can be considered as a separate rocket with its own rocket engine and fuel supply for flight.
Construction of space rocket stages.
First stage of a space rocket the largest, in a rocket for flight, the space of the 1st stage engines can be up to 6 and the heavier the load that needs to be launched into space, the more engines there are in the first stage of the rocket.
IN classic version there are three of them, located symmetrically along the edges isosceles triangle as if encircling the perimeter of the rocket. This stage is the largest and most powerful; it is the one that lifts off the rocket. When the fuel in the first stage of a rocket is used up, the entire stage is discarded.
After this, the rocket's movement is controlled by the second stage engines. They are sometimes called boosters, since it is with the help of the second stage engines that the rocket reaches the first escape velocity, sufficient to enter low-Earth orbit.
This can be repeated several times, with each rocket stage weighing less than the previous one, since the Earth’s gravitational force decreases with altitude.
The number of times this process is repeated is the number of stages a space rocket contains. The last stage of the rocket is designed for maneuvering (propulsion engines for flight correction are present in each stage of the rocket) and delivering the payload and astronauts to their destination.
We reviewed the device and rocket operating principle, ballistic multistage rockets are designed in exactly the same way and are not fundamentally different from space rockets, terrible weapon carrier nuclear weapon. They are capable of completely destroying both life on the entire planet and life itself.
Multistage ballistic missiles enter low-Earth orbit and from there hit ground targets with separated warheads with nuclear charges. Moreover, it takes them 20-25 minutes to fly to the most remote point.
APUSK was produced using a multi-stage rocket,” we have read these words many times in reports about the launch of the world’s first artificial satellites Earth, about the creation of a satellite of the Sun, about the launch of space rockets to the Moon. Just one short phrase, and how much inspired work of scientists, engineers and workers of our Motherland is hidden behind these six words!
What are modern multistage rockets? Why did it become necessary to use rockets consisting of a large number of stages for space flights? What technical effect does increasing the number of rocket stages give?
Let's try to briefly answer these questions. Flights into space require huge reserves of fuel. They are so large that they cannot be placed in the tanks of a single-stage rocket. With the modern level of engineering science, it is possible to build a rocket in which the fuel would account for up to 80-90% of its total weight. And for flights to other planets, the required fuel reserves must be hundreds and even thousands of times greater than the own weight of the rocket and the payload in it. With the fuel reserves that can be placed in the tanks of a single-stage rocket, it is possible to achieve flight speeds of up to 3-4 km/sec. Improving rocket engines, finding the most advantageous types of fuel, using better structural materials and further improving the design of rockets will certainly make it possible to slightly increase the speed of single-stage rockets. But it will still be very far from cosmic speeds.
To achieve cosmic speeds, K. E. Tsiolkovsky proposed the use of multi-stage rockets. The scientist himself figuratively called them “rocket trains.” According to Tsiolkovsky, a rocket train, or, as we say now, a multi-stage rocket, should consist of several rockets mounted on one another. The bottom rocket is usually the largest. She carries the entire “train” on herself. Subsequent steps are made of smaller and smaller sizes.
When taking off from the surface of the Earth, the engines of the lower rocket operate. They operate until all the fuel in its tanks is used up. When the tanks of the first stage are empty, it is separated from the upper rockets so as not to burden their further flight with dead weight. The separated first stage with empty tanks continues to fly upward for some time by inertia, and then falls to the ground. To preserve the first stage for the sake of reuse you can ensure its descent by parachute.
After separation of the first stage, the second stage engines are switched on. They begin to operate when the rocket has already risen to a certain altitude and has a significant flight speed. The second stage engines accelerate the rocket further, increasing its speed by several kilometers per second. After all the fuel contained in the tanks of the second stage is consumed, it is also dumped. The further flight of the composite rocket is ensured by the operation of the third stage engines. Then the third stage is reset. The line is approaching the fourth stage engines. Having completed the work assigned to them, they increase the speed of the rocket by a certain amount, and then give way to the fifth stage engines. After the fifth stage is reset, the engines of the sixth begin to operate.
Thus, each stage of the rocket successively increases its flight speed, and the last, upper stage reaches the required cosmic speed in vacuum. If the task is to land on another planet and return back to Earth, then the rocket launched into space, in turn, must consist of several stages, sequentially switched on when descending to the planet and when taking off from it.
It is interesting to see the effect of using a large number of stages on rockets.
Let's take a single-stage rocket with a launch weight of 500 tons. Let us assume that this weight is distributed as follows: payload - 1 ton, dry weight of the stage - 99.8 tons and fuel - 399.2 tons. Consequently, the structural perfection of this rocket is such that the weight fuel is 4 times the dry weight of the stage, that is, the weight of the rocket itself without fuel and payload. The Tsiolkovsky number, that is, the ratio of the launch weight of the rocket to its weight after all the fuel has been consumed, for this rocket will be equal to 4.96. This number and the rate at which gas flows out of the engine nozzle determine the speed that the rocket can achieve. Let's now try to replace the single-stage rocket with a two-stage one. Let us again take a payload of 1 ton and assume that the design perfection of the stages and the gas flow rate will remain the same as in a single-stage rocket. Then, as calculations show, to achieve the same flight speed as in the first case, a two-stage rocket with a total weight of only 10.32 tons will be required, that is, almost 50 times lighter than a single-stage one. The dry weight of a two-stage rocket will be 1.86 tons, and the weight of the fuel placed in both stages will be 7.46 tons. As we can see, in the example under consideration, replacing a single-stage rocket with a two-stage one makes it possible to reduce metal and fuel consumption by 54 times when launching the same payload .
Let's take, for example, a space rocket with a payload of 1 ton. Let this rocket must penetrate the dense layers of the atmosphere and, flying into airless space, develop a second escape velocity of 11.2 km/sec. Our diagrams show the change in the weight of such a space rocket depending on the weight fraction of fuel in each stage and the number of stages (see page 22).
It is not difficult to calculate that if you build a rocket whose engines eject gases at a speed of 2,400 m/sec and in each stage the fuel accounts for only 75% of the weight, then even with six stages, the take-off weight of the rocket will be very large - almost 5.5 thousand tons. By improving the design characteristics of rocket stages, it is possible to achieve a significant reduction in launch weight. So, for example, if fuel accounts for 90% of the stage's weight, then a six-stage rocket can weigh 400 tons.
An exceptionally great effect comes from using high-calorie fuel in rockets and increasing the efficiency of their engines. If in this way we increase the speed of gas flow from the engine nozzle by only 300 m/sec, bringing it to the value indicated on the graph - 2,700 m/sec, then the launch weight of the rocket can be reduced several times. A six-stage rocket, in which the weight of the fuel is only 3 times greater than the weight of the stage structure, will have a launch weight of approximately 1.5 thousand tons. And by reducing the weight of the structure to 10% of the total weight of each stage, we can reduce the launch weight of the rocket with the same number of stages up to 200 t.
If we increase the gas flow rate by another 300 m/sec, that is, take it equal to 3 thousand m/sec, then an even greater reduction in weight will occur. For example, a six-stage rocket with a fuel weight fraction of 75% will have a launch weight of 600 tons. By increasing the fuel weight fraction to 90%, it is possible to create a space rocket with only two stages. Its weight will be about 850 tons. By doubling the number of stages, you can reduce the weight of the rocket to 140 tons. And with six stages, the take-off weight will drop to 116 tons.
This is how the number of stages, their design perfection and the speed of gas flow affect the weight of the rocket.
Why is it that as the number of stages increases, the required fuel reserves decrease, and with them the total weight rockets? This happens because than larger number stages, the more often empty tanks will be discarded, the faster the rocket will be freed from useless cargo. Moreover, as the number of stages increases, first the take-off weight of the rocket decreases very strongly, and then the effect of increasing the number of stages becomes less significant. It can also be noted, as can be clearly seen in the graphs above, that for rockets with relatively poor design characteristics, increasing the number of stages has a greater effect than for rockets with a high percentage of fuel in each stage. This is quite understandable. If the bodies of each stage are very heavy, then they must be dropped as quickly as possible. And if the hull is very light in weight, then it does not burden the missiles too much and frequent drops of empty hulls no longer have such a great effect.
When rockets fly to other planets, the required fuel consumption is not limited to the amount required for acceleration when taking off from Earth. Flying up to another planet spaceship falls into its sphere of attraction and begins to approach its surface with increasing speed. If the planet is deprived of an atmosphere capable of extinguishing at least part of the speed, then the rocket, when falling on the surface of the planet, will develop the same speed as is necessary to depart from this planet, that is, the second escape velocity. The value of the second escape velocity, as is known, is different for each planet. For example, for Mars it is 5.1 km/sec, for Venus - 10.4 km/sec, for the Moon - 2.4 km/sec. In the case when the rocket approaches the sphere of gravity of the planet, having a certain speed relative to the latter, the speed of the rocket's fall will be even greater. For example, the second Soviet space rocket reached the surface of the Moon at a speed of 3.3 km/sec. If the task is to ensure a smooth landing of the rocket on the surface of the Moon, then additional fuel reserves must be on board the rocket. To extinguish any speed, it is necessary to consume the same amount of fuel as is necessary for the rocket to develop the same speed. Therefore, a space rocket designed for safe delivery on the lunar surface of some kind of cargo must carry significant reserves of fuel. A single-stage rocket with a payload of 1 ton should have a weight of 3-4.5 tons, depending on its design perfection.
Previously, we showed what enormous weight rockets must have in order to carry space a load of 1 ton. And now we see that only a third or even a fourth of this load can be safely lowered to the surface of the Moon. The rest must be fuel, fuel storage tanks, engine and control system.
What should ultimately be the starting weight of a space rocket designed to safely deliver scientific equipment or other payload weighing 1 ton to the lunar surface?
In order to give an idea of ships of this type, our figure conventionally shows a sectional view of a five-stage rocket designed to deliver a container with scientific equipment weighing 1 ton to the lunar surface. The calculation of this rocket was based on the technical data given in large quantities books (for example, in the books by V. Feodosyev and G. Sinyarev “Introduction to Rocketry” and Sutton “Rocket Engines”).
Rocket engines running on liquid fuel were taken. To supply fuel to the combustion chambers, turbopump units driven by hydrogen peroxide decomposition products are provided. average speed gas outflow for the first stage engines is taken to be 2,400 m/sec. Upper stage engines operate in highly rarefied layers of the atmosphere and in airless space, so their efficiency turns out to be somewhat greater and for them the gas outflow velocity is assumed to be 2,700 m/sec. For the design characteristics of the stages, the following values were adopted that are found in rockets described in the technical literature.
With the selected initial data, the following weight characteristics of the space rocket were obtained: take-off weight - 3,348 tons, including 2,892 tons - fuel, 455 tons - structure and 1 t - payload. The weight of the individual stages was distributed as follows: the first stage - 2,760 tons, the second - 495 tons, the third - 75.5 tons, the fourth - 13.78 tons, the fifth - 2.72 tons. The height of the rocket reached 60 m, the diameter of the lower stage - 10 m.
The first stage contains 19 engines with a thrust of 350 tons each. On the second - 3 of the same engines, on the third - 3 engines with a thrust of 60 tons. On the fourth - one with a thrust of 35 tons and on the last stage - an engine with a thrust of 10 tons.
When taking off from the surface of the Earth, the first stage engines accelerate the rocket to a speed of 2 km/sec. After the empty casing of the first stage is released, the engines of the next three stages are turned on, and the rocket acquires a second escape velocity.
Then the rocket flies by inertia towards the Moon. Approaching its surface, the rocket turns its nozzle down. The fifth stage engine turns on. It dampens the speed of fall, and the rocket smoothly descends to the lunar surface.
The above figure and the calculations related to it, of course, do not represent a real project for a lunar rocket. They are given only to give a first idea of the scale of space multistage rockets. It is absolutely clear that the design of a rocket, its dimensions and weight depend on the level of development of science and technology, on the materials available to the designers, on the fuel used and the quality of the rocket engines, on the skill of its builders. The creation of space rockets provides limitless scope for the creativity of scientists, engineers, and technologists. There are still many discoveries and inventions to be made in this area. And with each new achievement, the characteristics of missiles will change.
Just as modern airships such as IL-18, TU-104, TU-114 are not similar to the airplanes that flew at the beginning of this century, so space rockets will be continuously improved. Over time, rocket engines will use more than just energy to fly into space. chemical reactions, but also other energy sources, for example energy nuclear processes. As the types of rocket engines change, the design of the rockets themselves will also change. But the wonderful idea of K. E. Tsiolkovsky about creating “ rocket trains"will always have an honorable role in exploring the vast expanses of space.
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Multistage rocket
A rocket whose launch vehicle includes more than one stage. A stage is a part of a rocket that is separated during flight, including units and systems that have completed their functioning at the time of separation. Home integral part stage is the propulsion system (see Rocket engine) of the stage, the operating time of which determines the operating time of other elements of the stage.
Propulsion systems belonging to different stages can operate either in series or in parallel. During sequential operation, the propulsion system of the next stage is switched on after the operation of the propulsion system of the previous stage is completed. In parallel operation, the propulsion systems of adjacent stages operate together, but the propulsion system of the preceding stage completes its operation and is separated before the operation of the subsequent stage is completed. Stage numbers are determined by the order in which they are separated from the rocket.
The prototype of multistage rockets are composite rockets, in which the spent parts were not supposed to be separated sequentially. Composite rockets were first mentioned in the 16th century in the work “On Pyrotechnics” (Venice, 1540) by the Italian scientist and engineer Vannoccio Biringuccio (1480-1539).
In the 17th century, the Polish-Belarusian-Lithuanian scientist Kazimir Seminovich (Seminavichus) (1600-1651) in his book “The Great Art of Artillery” (Amsterdam, 1650), which for 150 years was fundamental scientific work on artillery and pyrotechnics, provides drawings of multi-stage rockets. It is Semenovich, according to many experts, who is the first inventor of a multi-stage rocket.
The first patent in 1911 for a multistage rocket was received by the Belgian engineer Andre Bing. The Bing rocket moved by sequentially detonating powder bombs. In 1913, the American scientist Robert Goddard became the owner of the patent. The Godard rocket design provides for sequential separation of stages.
At the beginning of the 20th century, a number of famous scientists were engaged in the study of multistage rockets. The most significant contribution to the idea of creating and practical use multistage rockets were contributed by K.E. Tsiolkovsky (1857-1935), who outlined his views in the works “Rocket Space Trains” (1927) and “ Highest speed rockets" (1935). Ideas of Tsiolkovsky K.E. have become widespread and implemented.
In the Strategic Missile Forces, the first multi-stage missile put into service in 1960 was the R-7 missile (see Missile strategic purpose). The propulsion systems of two stages of the rocket, placed in parallel, using liquid oxygen and kerosene as fuel components, ensured the delivery of 5400 kg. payload for a range of up to 8000 km. It was impossible to achieve the same results with a single-stage rocket. In addition, in practice it was found that when moving from a single-stage to a two-stage rocket design, it is possible to achieve a multiple increase in range with a less significant increase in launch mass.
This advantage was clearly demonstrated during the creation of a single-stage rocket. medium range R-14 and two-stage intercontinental missile R-16. While the main energy characteristics are similar, the flight range of the R-16 missile is 2.5 times greater than the R-14 missile, while its launch mass is only 1.6 times greater.
While creating modern missiles the choice of the number of stages is determined by many factors, namely, the energy characteristics of the fuels, the properties of structural materials, the perfection of the design of the units and systems of the rocket, etc. It is also taken into account that the design of a rocket with a smaller number of stages is simpler, its cost is lower, and the creation time is shorter. Analysis of the design of modern rockets makes it possible to identify the dependence of the number of stages on the type of fuel and flight range.