The statement made by Vladimir Putin during his address to the Federal Assembly about the presence in Russia of a nuclear-powered cruise missile caused a great stir in society and the media. At the same time, little was known about what such an engine is and about the possibilities of its use, both for the general public and for specialists.

Reedus tried to figure out what kind of technical device the president could be talking about and what makes it unique.

Considering that the presentation at the Manege was made not for an audience of technical specialists, but for the “general” public, its authors could allow a certain substitution of concepts, Georgy Tikhomirov, deputy director of the Institute of Nuclear Physics and Technology of the National Research Nuclear University MEPhI, does not exclude.

“What the president said and showed, experts call compact power plants, experiments with which were initially carried out in aviation, and then during the exploration of deep space. These were attempts to solve the insoluble problem of sufficient fuel for flights over unlimited distances. In this sense, the presentation is absolutely correct: the presence of such an engine provides energy to the systems of a rocket or any other apparatus for an arbitrarily long time,” he told Reedus.

Work with such an engine in the USSR began exactly 60 years ago under the guidance of academicians M. Keldysh, I. Kurchatov and S. Korolev. In the same years, similar work was carried out in the United States, but was curtailed in 1965. In the USSR, work continued for about a decade before they were also recognized as irrelevant. Perhaps that is why Washington did not wince much, saying that they were not surprised by the presentation of the Russian missile.

In Russia, the idea of a nuclear engine has never died - in particular, since 2009, the practical development of such an installation has been underway. Judging by the timing, the tests announced by the president fit exactly into this joint project of Roscosmos and Rosatom, since the developers planned to conduct field tests of the engine in 2018. Perhaps, due to political reasons, they pulled themselves up a little and shifted the deadlines “to the left”.

“Technologically, it is arranged in such a way that the nuclear power unit heats the gas coolant. And this heated gas either rotates the turbine or creates jet thrust directly. A certain cunning in the presentation of the rocket, which we heard, is that the range of its flight is still not infinite: it is limited by the volume of the working fluid - liquid gas, which can physically be pumped into the rocket tanks, ”says the specialist.

At the same time, a space rocket and a cruise missile have fundamentally different flight control schemes, since they have different tasks. The first one flies in airless space, it does not need to maneuver - it is enough to give it an initial impulse, and then it moves along the calculated ballistic trajectory.

A cruise missile, on the contrary, must continuously change its trajectory, for which it must have enough fuel to create impulses. Whether this fuel will be ignited by a nuclear power plant or a traditional one is not important in this case. Only the supply of this fuel is important, Tikhomirov emphasizes.

“The meaning of a nuclear installation during flights into deep space is the presence of an energy source on board to power the systems of the apparatus for an unlimited time. At the same time, it may be not only nuclear reactor, but also radioisotope thermoelectric generators. And the meaning of such an installation on a rocket, the flight of which will not last longer than a few tens of minutes, is not yet completely clear to me, ”the physicist admits.

The report at the Manege was only a couple of weeks late compared to NASA's February 15 announcement that the Americans were resuming nuclear rocket propulsion research that they abandoned half a century ago.

By the way, in November 2017, the China Aerospace Science and Technology Corporation (CASC) already announced that before 2045, a nuclear-powered spacecraft would be created in China. Therefore, today we can safely say that the world nuclear propulsion race has begun.

Russia has been and still remains a leader in the field of nuclear space energy. Organizations such as RSC Energia and Roskosmos have experience in designing, building, launching and operating spacecraft equipped with a nuclear power source. A nuclear engine makes it possible to operate aircraft for many years, greatly increasing their practical suitability.

historical chronicle

At the same time, the delivery of a research apparatus to the orbits of the distant planets of the solar system requires an increase in the resource of such a nuclear installation to 5-7 years. It has been proved that a complex with a nuclear propulsion system with a power of about 1 MW as part of a research spacecraft will allow for accelerated delivery of artificial satellites of the most distant planets, planetary rovers to the surface of natural satellites of these planets and delivery of soil from comets, asteroids, Mercury and satellites of Jupiter and Saturn.

Reusable tug (MB)

One of the most important ways to increase the efficiency of transport operations in space is the reusable use of elements of the transport system. A nuclear engine for spacecraft with a power of at least 500 kW makes it possible to create a reusable tug and thereby significantly increase the efficiency of a multi-link space transport system. Such a system is especially useful in a program to ensure large annual cargo flows. An example would be the Moon exploration program with the creation and maintenance of a constantly growing habitable base and experimental technological and industrial complexes.

Calculation of cargo turnover

According to the design studies of RSC Energia, during the construction of the base, modules weighing about 10 tons should be delivered to the Moon's surface, up to 30 tons into the Moon's orbit. , and the annual cargo flow to ensure the functioning and development of the base is 400-500 tons.

However, the principle of operation of a nuclear engine does not allow to disperse the transporter quickly enough. Due to the long time of transportation and, accordingly, the significant time spent by the payload in the radiation belts of the Earth, not all cargo can be delivered using tugs with nuclear engine. Therefore, the cargo flow that can be ensured on the basis of NEP is estimated at only 100-300 tons/year.

Economic efficiency

As a criterion for the economic efficiency of the interorbital transport system, it is advisable to use the value of the unit cost of transporting a unit mass of payload (PG) from the Earth's surface to the target orbit. RSC Energia developed an economic and mathematical model that takes into account the main cost components in the transport system:

for the creation and launch of tug modules into orbit;
for the purchase of a working nuclear installation;
operating costs, as well as R&D costs and possible capital costs.

Cost indicators depend on the optimal parameters of the MB. Using this model, a comparative economic efficiency the use of a reusable tug based on nuclear propulsion systems with a capacity of about 1 MW and a disposable tug based on advanced liquid propellant ones in the program to ensure the delivery of a payload with a total mass of 100 t/year from the Earth to the lunar orbit with a height of 100 km. When using the same launch vehicle with a carrying capacity equal to the carrying capacity of the Proton-M launch vehicle and a two-launch scheme for constructing a transport system, the unit cost of delivering a unit mass of payload using a tug based on a nuclear engine will be three times lower than when using disposable tugboats based on rockets with liquid engines of the DM-3 type.

Conclusion

An efficient nuclear engine for space contributes to the solution environmental issues Earth, manned flight to Mars, creation of a system wireless transmission energy in space, the implementation of high-security burial in space of especially dangerous radioactive waste from ground-based nuclear energy, the creation of a habitable lunar base and the beginning of industrial exploration of the Moon, and the protection of the Earth from asteroid-comet hazard.

Alexander Losev

The rapid development of rocket and space technology in the 20th century was due to the military-strategic, political and, to a certain extent, ideological goals and interests of the two superpowers - the USSR and the USA, and all state space programs were a continuation of their military projects, where the main task was the need to ensure defense capability and strategic parity with a potential adversary. The cost of creating equipment and the cost of operating then did not have a fundamental significance. Enormous resources were allocated to the creation of launch vehicles and spacecraft, and the 108 minutes of Yuri Gagarin's flight in 1961 and the television broadcast of Neil Armstrong and Buzz Aldrin from the surface of the Moon in 1969 were not just triumphs of scientific and technical thought, they were also considered as strategic victories in battles of the Cold War.

But after the Soviet Union collapsed and dropped out of the race for world leadership, its geopolitical opponents, primarily the United States, no longer needed to implement prestigious, but extremely costly space projects in order to prove to the whole world the superiority of the Western economic system and ideological concepts.
In the 90s, the main political tasks of the past lost their relevance, the bloc confrontation was replaced by globalization, pragmatism prevailed in the world, so most space programs were curtailed or postponed, only the ISS remained from the large-scale projects of the past. In addition, Western democracy has delivered all the expensive government programs dependent on electoral cycles.
The voter support needed to gain or stay in power makes politicians, parliaments and governments lean towards populism and to solve immediate problems, so spending on space exploration is reduced year by year.
Most of the fundamental discoveries were made in the first half of the twentieth century, and today science and technology have reached certain limits, in addition, the popularity of scientific knowledge has decreased all over the world, and the quality of teaching mathematics, physics and other natural sciences has deteriorated. This was the reason for the stagnation, including in the space sector, of the last two decades.
But now it becomes obvious that the world is approaching the end of the next technological cycle based on the discoveries of the last century. Therefore, any power that will have fundamentally new promising technologies at the time of the change in the global technological order will automatically secure world leadership for at least the next fifty years.

Principal device of a nuclear rocket engine with hydrogen as a working fluid

This is realized in the United States, where a course has been taken to revive American greatness in all spheres of activity, and in China, challenging American hegemony, and in the European Union, which is trying with all its might to maintain its weight in the global economy.
There is an industrial policy and they are seriously engaged in the development of their own scientific, technical and production potential, and the space sector can become the best testing ground for testing new technologies and for proving or refuting scientific hypotheses that can lay the foundation for creating a fundamentally different, more advanced technology of the future.
And it is quite natural to expect that the United States will be the first country where deep space exploration projects are resumed in order to create unique innovative technologies both in the field of weapons, transport and structural materials, and in biomedicine and in the field of telecommunications
True, not even the United States is guaranteed success on the path to creating revolutionary technologies. There is a high risk of ending up in a dead end, improving half-century-old chemical-propellant rocket engines, as Elon Musk's SpaceX is doing, or building long-haul life support systems similar to those already implemented on the ISS.
Can Russia, whose stagnation in the space sector is becoming more noticeable every year, make a breakthrough in the race for future technological leadership in order to remain in the club of superpowers, and not in the list of developing countries?
Yes, of course, Russia can, and moreover, a significant step forward has already been made in nuclear power and nuclear technologies. rocket engines, despite the chronic underfunding of the space industry.
The future of astronautics is the use of nuclear energy. To understand how nuclear technology and space are related, it is necessary to consider the basic principles of jet propulsion.
So, the main types of modern space engines are created on the principles of chemical energy. These are solid-propellant boosters and liquid-propellant rocket engines, in their combustion chambers, fuel components (fuel and oxidizer), entering into an exothermic physico-chemical combustion reaction, form a jet stream that ejects tons of matter from the engine nozzle every second. The kinetic energy of the working fluid of the jet is converted into a reactive force sufficient to propel the rocket. The specific impulse (the ratio of thrust produced to the mass of fuel used) of such chemical engines depends on the components of the fuel, the pressure and temperature in the combustion chamber, and also on the molecular weight of the gaseous mixture ejected through the engine nozzle.
And the higher the temperature of the substance and the pressure inside the combustion chamber, and the lower molecular mass gas, the higher the specific impulse, and hence the efficiency of the engine. Specific impulse is the amount of motion, and it is customary to measure it in meters per second, as well as speed.
In chemical engines, fuel mixtures oxygen-hydrogen and fluorine-hydrogen (4500–4700 m/s) give the highest specific impulse, but rocket engines powered by kerosene and oxygen, such as Soyuz and missiles "Falcon" Mask, as well as engines on asymmetric dimethylhydrazine (UDMH) with an oxidizer in the form of a mixture of nitrogen tetroxide and nitric acid (Soviet and Russian "Proton", French "Arian", American "Titan"). Their efficiency is 1.5 times lower than that of hydrogen-fueled engines, but an impulse of 3000 m / s and power is quite enough to make it economically profitable to launch tons of payloads into near-Earth orbits.
But flights to other planets require a much larger spacecraft than anything that has been created by mankind before, including the modular ISS. In these ships, it is necessary to ensure both the long-term autonomous existence of the crews, and a certain supply of fuel and the service life of the main engines and engines for maneuvers and orbit correction, provide for the delivery of astronauts in a special landing module to the surface of another planet, and their return to the main transport ship, and then and return of the expedition to Earth.
The accumulated engineering and technical knowledge and the chemical energy of the engines make it possible to return to the Moon and reach Mars, so it is highly likely that in the next decade humanity will visit the Red Planet.
If we rely only on available space technologies, then the minimum mass of a habitable module for a manned flight to Mars or to the satellites of Jupiter and Saturn will be approximately 90 tons, which is 3 times more than the lunar ships of the early 1970s, which means that launch vehicles for their insertion into reference orbits for further flight to Mars will be much superior to the Saturn-5 (launch weight 2965 tons) of the Apollo lunar project or the Soviet carrier Energia (launch weight 2400 tons). It will be necessary to create an interplanetary complex weighing up to 500 tons in orbit. A flight on an interplanetary ship with chemical rocket engines will require from 8 months to 1 year of time only in one direction, because you will have to do gravitational maneuvers, using the force of gravity of the planets for additional acceleration of the ship, and a huge supply of fuel.
But using the chemical energy of rocket engines, humanity will not fly beyond the orbit of Mars or Venus. We need other speeds of flight of spaceships and other more powerful energy of movement.

Modern nuclear rocket engine project Princeton Satellite Systems

To explore deep space, it is necessary to significantly increase the thrust-to-weight ratio and efficiency of a rocket engine, which means increasing its specific impulse and service life. And for this, it is necessary to heat the gas or substance of the working fluid with a low atomic mass inside the engine chamber to temperatures several times higher than the chemical combustion temperature of traditional fuel mixtures, and this can be done using a nuclear reaction.
If, instead of a conventional combustion chamber, a nuclear reactor is placed inside a rocket engine, into the active zone of which a substance in liquid or gaseous form is supplied, then it, heating up under high pressure up to several thousand degrees, will begin to be ejected through the nozzle channel, creating jet thrust. The specific impulse of such a nuclear jet engine will be several times greater than that of a conventional one based on chemical components, which means that the efficiency of both the engine itself and the launch vehicle as a whole will increase many times over. In this case, an oxidizer for fuel combustion is not required, and light hydrogen gas can be used as a substance that creates jet thrust, but we know that the lower the molecular weight of the gas, the higher the momentum, and this will significantly reduce the mass of the rocket at best performance engine power.
A nuclear engine would be better than a conventional one, because in the reactor zone light gas can be heated to temperatures in excess of 9 thousand degrees Kelvin, and a jet of such superheated gas will provide a much higher specific impulse than ordinary chemical engines can give. But that's in theory.
The danger is not even that during the launch of a launch vehicle with such a nuclear installation, radioactive contamination of the atmosphere and space around the launch pad can occur, the main problem is that at high temperatures the engine itself can melt along with the spacecraft. Designers and engineers understand this and have been trying to find suitable solutions for several decades.
Nuclear rocket engines (NRE) already have their own history of creation and operation in space. The first development of nuclear engines began in the mid-1950s, that is, even before manned space flight, and almost simultaneously in the USSR and the USA, and the very idea of using nuclear reactors to heat the working substance in a rocket engine was born together with the first reactors in mid-40s, that is, more than 70 years ago.
In our country, the thermal physicist Vitaly Mikhailovich Ievlev became the initiator of the creation of the NRE. In 1947, he presented a project that was supported by S. P. Korolev, I. V. Kurchatov and M. V. Keldysh. Initially, it was planned to use such engines for cruise missiles, and then put them on ballistic missiles. The leading defense design bureaus of the Soviet Union, as well as the research institutes NIITP, CIAM, IAE, VNIINM, took up the development.
The Soviet nuclear engine RD-0410 was assembled in the mid-60s by the Voronezh "Design Bureau of Chemical Automation", where most liquid rocket engines for space technology were created.
Hydrogen was used as a working fluid in RD-0410, which in liquid form passed through the "cooling jacket", removing excess heat from the walls of the nozzle and preventing it from melting, and then entered the reactor core, where it was heated to 3000K and ejected through the channel nozzles, thus converting thermal energy into kinetic and creating a specific impulse of 9100 m / s.
In the USA, the NRE project was launched in 1952, and the first operating engine was created in 1966 and was named NERVA (Nuclear Engine for Rocket Vehicle Application). In the 60s - 70s, the Soviet Union and the United States tried not to yield to each other.
True, both our RD-0410 and the American NERVA were solid-phase NREs (nuclear fuel based on uranium carbides was in the reactor in a solid state), and their operating temperature was in the range of 2300–3100K.
In order to increase the temperature of the core without the risk of an explosion or melting of the reactor walls, it is necessary to create conditions for a nuclear reaction under which the fuel (uranium) passes into a gaseous state or turns into a plasma and is kept inside the reactor due to a strong magnetic field, without touching the walls. And then the hydrogen entering the reactor core “flows around” the uranium in the gas phase, and turning into plasma, is ejected through the nozzle channel at a very high speed.
This type of engine is called the gas-phase YRD. The temperatures of gaseous uranium fuel in such nuclear engines can range from 10,000 to 20,000 degrees Kelvin, and the specific impulse can reach 50,000 m/s, which is 11 times higher than the most efficient chemical rocket engines.
The creation and use in space technology of gas-phase NREs of open and closed types is the most promising direction in the development of space rocket engines and exactly what humanity needs to explore the planets of the solar system and their satellites.
The first studies on the gas-phase NRE project began in the USSR in 1957 at the Research Institute of Thermal Processes (M. V. Keldysh Research Center), and the very decision to develop nuclear space power plants based on gas-phase nuclear reactors was made in 1963 by Academician V. P. Glushko (NPO Energomash), and then approved by a resolution of the Central Committee of the CPSU and the Council of Ministers of the USSR.
The development of the gas-phase NRE was carried out in the Soviet Union for two decades, but, unfortunately, was never completed due to insufficient funding and the need for additional fundamental research in the field of thermodynamics of nuclear fuel and hydrogen plasma, neutron physics and magnetohydrodynamics.
Soviet nuclear scientists and design engineers faced a number of problems, such as achieving criticality and ensuring the stability of the operation of a gas-phase nuclear reactor, reducing the loss of molten uranium during the release of hydrogen heated to several thousand degrees, thermal protection of the nozzle and magnetic field generator, accumulation of uranium fission products , the choice of chemically resistant structural materials, etc.
And when the Energia launch vehicle began to be created for the Soviet Mars-94 program, the first manned flight to Mars, the nuclear engine project was postponed indefinitely. The Soviet Union did not have enough time, and most importantly political will and economic efficiency, to land our cosmonauts on the planet Mars in 1994. This would be an indisputable achievement and proof of our leadership in high technologies over the next few decades. But space, like many other things, was betrayed by the last leadership of the USSR. History cannot be changed, departed scientists and engineers cannot be returned, and lost knowledge cannot be restored. A lot of things will have to be re-created.
But space nuclear power is not limited to the sphere of solid- and gas-phase NREs. To create a heated flow of matter in a jet engine, you can use electrical energy. This idea was first expressed by Konstantin Eduardovich Tsiolkovsky back in 1903 in his work "The Study of World Spaces with Reactive Instruments".
And the first electrothermal rocket engine in the USSR was created in the 1930s by Valentin Petrovich Glushko, a future academician of the USSR Academy of Sciences and head of NPO Energia.
The principles of operation of electric rocket engines can be different. They are usually divided into four types:

electrothermal (heating or electric arc). In them, the gas is heated to temperatures of 1000–5000K and is ejected from the nozzle in the same way as in the NRE.
electrostatic engines (colloidal and ionic), in which the working substance is ionized first, and then positive ions (atoms devoid of electrons) are accelerated in an electrostatic field and are also ejected through the nozzle channel, creating jet thrust. Stationary plasma engines also belong to electrostatic engines.
magnetoplasma and magnetodynamic rocket engines. There, the gaseous plasma is accelerated by the Ampère force in perpendicularly intersecting magnetic and electric fields.
pulse rocket engines, which use the energy of gases arising from the evaporation of the working fluid in an electric discharge.

The advantage of these electric rocket engines is low consumption of the working fluid, efficiency up to 60% and high speed particle flux, which can significantly reduce the mass of the spacecraft, but there is also a minus - a low thrust density, and, accordingly, low power, as well as the high cost of the working fluid (inert gases or alkali metal vapors) for creating plasma.
All of the listed types of electric motors have been implemented in practice and have been repeatedly used in space on both Soviet and American vehicles since the mid-1960s, but due to their low power, they were mainly used as orbit correction engines.
From 1968 to 1988, a whole series of Kosmos satellites was launched in the USSR with nuclear installations on board. The types of reactors were named: "Buk", "Topaz" and "Yenisei".
The reactor of the Yenisei project had a thermal power of up to 135 kW and an electrical power of about 5 kW. The heat carrier was a sodium-potassium melt. This project was closed in 1996.
For a real sustainer rocket motor, a very powerful source of energy is required. And the best source of energy for such space engines is a nuclear reactor.
Nuclear energy is one of the high-tech industries where our country maintains its leading position. And a fundamentally new rocket engine is already being created in Russia, and this project is close to successful completion in 2018. Flight tests are scheduled for 2020.
And if the gas-phase NRE is a topic of the future decades to which we will have to return after fundamental research, then its current alternative is a megawatt-class nuclear power plant (NPP), and it has already been created by Rosatom and Roscosmos enterprises since 2009.
NPO Krasnaya Zvezda, which is currently the only developer and manufacturer of space nuclear power plants in the world, as well as the Research Center named after N.I. M. V. Keldysh, NIKIET them. N. A. Dollezhala, Research Institute NPO Luch, Kurchatov Institute, IRM, IPPE, NIIAR and NPO Mashinostroeniya.
The nuclear power plant includes a high-temperature gas-cooled fast-neutron nuclear reactor with a turbomachine conversion of thermal energy into electrical energy, a system of refrigerator-emitters for removing excess heat into space, an instrument-assembly compartment, a block of marching plasma or ion electric motors and a container for placing a payload .
In a power plant, a nuclear reactor serves as a source of electricity for the operation of electric plasma engines, while the gas coolant of the reactor, passing through the core, enters the turbine of the electric generator and compressor and returns back to the reactor in a closed loop, and is not thrown into space as in the NRE, which makes the design more reliable and safe, and therefore suitable for manned astronautics .
It is planned that a nuclear power plant will be used for a reusable space tug to ensure the delivery of cargo during the exploration of the Moon or the creation of multi-purpose orbital complexes. The advantage will be not only the reusable use of elements of the transport system (which Elon Musk is trying to achieve in his SpaceX space projects), but also the ability to deliver three times more mass of cargo than on rockets with chemical jet engines of comparable power by reducing the launch mass of the transport system . The special design of the unit makes it safe for people and environment on the ground.
In 2014, the first standard design fuel element (fuel element) for this nuclear electric propulsion plant was assembled at OJSC Mashinostroitelny Zavod in Elektrostal, and in 2016 a reactor core basket simulator was tested.
Now (in 2017), work is underway to manufacture structural elements of the installation and test components and assemblies on mock-ups, as well as autonomous testing of turbomachine energy conversion systems and power unit prototypes. Completion of works is scheduled for the end of the next 2018, however, since 2015, the backlog from the schedule began to accumulate.
So, as soon as this installation is created, Russia will become the first country in the world to possess nuclear space technologies, which will form the basis of not only future projects for the development of the solar system, but also terrestrial and extraterrestrial energy. Space nuclear power plants can be used to create systems for remote transmission of electricity to the Earth or to space modules using electromagnetic radiation. And this will also become the advanced technology of the future, where our country will have a leading position.
On the basis of the developed plasma motors, powerful propulsion systems will be created for long-distance human spaceflight and, first of all, for the exploration of Mars, the orbit of which can be reached in just 1.5 months, and not more than a year, as when using conventional chemical jet engines .
And the future always starts with a revolution in energy. And nothing else. Energy is primary and it is the magnitude of energy consumption that affects technical progress, defense capability and the quality of life of people.

NASA experimental plasma rocket engine

Soviet astrophysicist Nikolai Kardashev proposed a scale for the development of civilizations back in 1964. According to this scale, the level of technological development of civilizations depends on the amount of energy that the population of the planet uses for their needs. So civilization I type uses all the available resources available on the planet; type II civilization - receives the energy of its star, in the system of which it is located; and a type III civilization uses the available energy of its galaxy. Humanity has not yet grown to a type I civilization on this scale. We use only 0.16% of the total potential energy supply of the planet Earth. This means that Russia and the whole world have room to grow, and these nuclear technologies will open the way for our country not only into space, but also future economic prosperity.
And, perhaps, the only option for Russia in the scientific and technical sphere is now to make a revolutionary breakthrough in nuclear space technologies in order to overcome the many years behind the leaders in one “jump” and be immediately at the origins of a new technological revolution in the next cycle of development of human civilization. Such a unique chance falls to this or that country only once in several centuries.
Unfortunately, Russia, which has not paid due attention to the fundamental sciences and the quality of higher and secondary education over the past 25 years, runs the risk of losing this chance forever if the program is curtailed and the current scientists and engineers are not replaced by a new generation of researchers. The geopolitical and technological challenges that Russia will face in 10-12 years will be very serious, comparable to the threats of the mid-twentieth century. In order to preserve the sovereignty and integrity of Russia in the future, it is urgently necessary to start training specialists capable of responding to these challenges and creating something fundamentally new right now.
There is only about 10 years to turn Russia into a world intellectual and technological center, and this cannot be done without a serious change in the quality of education. For a scientific and technological breakthrough, it is necessary to return to the education system (both school and university) a systematic view of the picture of the world, scientific fundamentality and ideological integrity.
As for the current stagnation in the space industry, this is not terrible. The physical principles on which modern space technologies are based will be in demand by the conventional satellite services sector for a long time to come. Recall that mankind has been using sail for 5.5 thousand years, and the era of steam lasted almost 200 years, and only in the twentieth century the world began to change rapidly, because another scientific and technological revolution took place, which launched a wave of innovations and a change in technological patterns, which ultimately changed the world economy and politics. The main thing is to be at the origins of these changes. [email protected] ,
website: https://delpress.ru/information-for-subscribers.html

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Sergeev Alexey, 9 "A" class MOU "Secondary School No. 84"

Scientific consultant: , Deputy Director of the non-profit partnership for scientific and innovative activities "Tomsk Atomic Center"

Supervisor: , teacher of physics, MOU "Secondary School No. 84" ZATO Seversk

Introduction

Propulsion systems on board a spacecraft are designed to generate thrust or momentum. According to the type of thrust used by the propulsion system, they are divided into chemical (CRD) and non-chemical (NCRD). HRD are divided into liquid (LRE), solid fuel (RDTT) and combined (KRD). In turn, non-chemical propulsion systems are divided into nuclear (NRE) and electric (EP). The great scientist Konstantin Eduardovich Tsiolkovsky, a century ago, created the first model of a propulsion system that ran on solid and liquid fuels. After, in the second half of the 20th century, thousands of flights were carried out using mainly LRE and solid propellant rocket engines.

However, at present, for flights to other planets, not to mention the stars, the use of liquid propellant rocket engines and solid propellant rocket engines is becoming more and more unprofitable, although many rocket engines have been developed. Most likely, the possibilities of LRE and solid propellant rocket engines have completely exhausted themselves. The reason here is that the specific impulse of all chemical rocket engines is low and does not exceed 5000 m/s, which requires long-term operation of the propulsion system and, accordingly, large reserves of fuel to develop sufficiently high speeds, or, as is customary in astronautics, large values of the Tsiolkovsky number, t i.e. the ratio of the mass of a fueled rocket to the mass of an empty one. Thus, RN Energia, which puts 100 tons of payload into low orbit, has a launch mass of about 3,000 tons, which gives the Tsiolkovsky number a value in the range of 30.

For a flight to Mars, for example, the Tsiolkovsky number should be even higher, reaching values from 30 to 50. It is easy to estimate that with a payload of about 1,000 tons, namely, the minimum mass required to provide everything necessary for the crew starting to Mars taking into account the fuel supply for the return flight to the Earth, the initial mass of the spacecraft must be at least 30,000 tons, which is clearly beyond the level of development of modern astronautics based on the use of liquid propellant rocket engines and solid propellant rocket engines.

Thus, in order for manned crews to reach even the nearest planets, it is necessary to develop launch vehicles on engines operating on principles different from chemical propulsion. The most promising in this regard are electric jet engines (EP), thermochemical rocket engines and nuclear jet engines (NJ).

1.Basic concepts

A rocket engine is a jet engine that does not use the environment (air, water) for operation. The most widely used chemical rocket engines. Other types of rocket engines are being developed and tested - electric, nuclear and others. At space stations and vehicles, the simplest rocket engines operating on compressed gases are also widely used. They usually use nitrogen as the working fluid. /one/

Classification of propulsion systems

2. Purpose of rocket engines

According to their purpose, rocket engines are divided into several main types: accelerating (starting), braking, sustainer, control and others. Rocket engines are mainly used on rockets (hence the name). In addition, rocket engines are sometimes used in aviation. Rocket engines are the main engines in astronautics.

Military (combat) missiles usually have solid propellant engines. This is due to the fact that such an engine is refueled at the factory and does not require maintenance for the entire period of storage and service of the rocket itself. Solid propellant engines are often used as boosters for space rockets. Especially widely, in this capacity, they are used in the USA, France, Japan and China.

Liquid propellant rocket engines have higher thrust characteristics than solid propellant ones. Therefore, they are used to launch space rockets into orbit around the Earth and on interplanetary flights. The main liquid propellants for rockets are kerosene, heptane (dimethylhydrazine), and liquid hydrogen. For such fuels, an oxidizing agent (oxygen) is required. Nitric acid and liquefied oxygen are used as an oxidizing agent in such engines. Nitric acid is inferior to liquefied oxygen in terms of oxidizing properties, but does not require maintaining a special temperature regime during storage, refueling and use of rockets

Engines for space flights differ from terrestrial ones in that they, with the smallest possible mass and volume, must produce as much power as possible. In addition, they are subject to such requirements as exceptionally high efficiency and reliability, a significant operating time. According to the type of energy used, spacecraft propulsion systems are divided into four types: thermochemical, nuclear, electric, solar-sailing. Each of these types has its own advantages and disadvantages and can be used in certain conditions.

Currently, spacecraft, orbital stations and unmanned Earth satellites are launched into space by rockets equipped with powerful thermochemical engines. There are also miniature low thrust engines. This is a reduced copy of powerful engines. Some of them can fit in the palm of your hand. The thrust force of such engines is very small, but it is enough to control the position of the ship in space.

3. Thermochemical rocket engines.

It is known that the engine internal combustion, the furnace of a steam boiler - wherever combustion takes place, atmospheric oxygen takes the most active part. There is no air in outer space, and for the operation of rocket engines in outer space, it is necessary to have two components - fuel and an oxidizer.

In liquid thermochemical rocket engines, alcohol, kerosene, gasoline, aniline, hydrazine, dimethylhydrazine, liquid hydrogen are used as fuel. Liquid oxygen, hydrogen peroxide, nitric acid are used as an oxidizing agent. It is possible that liquid fluorine will be used as an oxidizing agent in the future, when methods for storing and using such an active chemical are invented.

Fuel and oxidizer for liquid-propellant jet engines are stored separately, in special tanks and pumped into the combustion chamber. When they are combined in the combustion chamber, a temperature of up to 3000 - 4500 ° C develops.

Combustion products, expanding, acquire a speed of 2500 to 4500 m/s. Starting from the engine housing, they create jet thrust. At the same time, the greater the mass and speed of the outflow of gases, the greater the thrust force of the engine.

It is customary to estimate the specific thrust of engines by the amount of thrust created by a unit mass of fuel burned in one second. This value is called the specific impulse of the rocket engine and is measured in seconds (kg of thrust / kg of burned fuel per second). The best solid propellant rocket engines have a specific impulse of up to 190 s, that is, 1 kg of fuel burning in one second creates a thrust of 190 kg. The hydrogen-oxygen rocket engine has a specific impulse of 350 s. Theoretically, a hydrogen-fluorine engine can develop a specific impulse of more than 400 s.

The commonly used scheme of a liquid propellant rocket engine works as follows. Compressed gas creates the necessary pressure in the tanks with cryogenic fuel to prevent the occurrence of gas bubbles in pipelines. Pumps supply fuel to rocket engines. Fuel is injected into the combustion chamber through a large number of injectors. Also, an oxidizing agent is injected into the combustion chamber through the nozzles.

In any car, during the combustion of fuel, large heat flows are formed that heat the walls of the engine. If you do not cool the walls of the chamber, then it will quickly burn out, no matter what material it is made of. A liquid-propellant jet engine is usually cooled with one of the propellant components. For this, the chamber is made two-wall. The cold fuel component flows in the gap between the walls.

Aluminum" href="/text/category/aluminij/" rel="bookmark">aluminum, etc. Especially as an additive to conventional fuels, such as hydrogen-oxygen. Such "triple compositions" are able to provide the highest possible speed for chemical fuels outflow - up to 5 km / s. But this is practically the limit of the resources of chemistry. It practically cannot do more. Although the proposed description is still dominated by liquid rocket engines, it must be said that the first in the history of mankind was created a thermochemical rocket engine on solid fuel - Solid propellant rocket engine. The fuel - for example, special gunpowder - is located directly in the combustion chamber. The combustion chamber with a jet nozzle filled with solid fuel - that's the whole design. The combustion mode of solid fuel depends on the purpose of the solid propellant rocket engine (starting, marching or combined). For solid propellant rockets used in military affairs are characterized by the presence of starting and sustainer engines. ny a short time, which is necessary for the rocket to leave the launcher and its initial acceleration. A marching solid propellant rocket engine is designed to maintain a constant rocket flight speed in the main (cruising) section of the flight path. The differences between them are mainly in the design of the combustion chamber and the profile of the combustion surface of the fuel charge, which determine the rate of fuel burning, on which the operating time and engine thrust depend. Unlike such rockets, space launch vehicles for launching Earth satellites, orbital stations and spacecraft, as well as interplanetary stations, operate only in the launch mode from the launch of a rocket to the launch of an object into orbit around the Earth or onto an interplanetary trajectory. In general, solid rocket engines do not have many advantages over liquid fuel engines: they are easy to manufacture, can be stored for a long time, are always ready for action, and are relatively explosion-proof. But in terms of specific thrust, solid propellant engines are 10-30% inferior to liquid ones.

4. Electric rocket motors

Almost all of the rocket engines discussed above develop tremendous thrust and are designed to put spacecraft into orbit around the Earth and accelerate them to space speeds for interplanetary flights. It is a completely different matter - propulsion systems for spacecraft already launched into orbit or onto an interplanetary trajectory. Here, as a rule, low-power motors (several kilowatts or even watts) are needed that can work hundreds and thousands of hours and turn on and off repeatedly. They allow you to maintain flight in orbit or along a given trajectory, compensating for the resistance to flight created by the upper atmosphere and the solar wind. In electric rocket engines, the working fluid is accelerated to a certain speed by heating it with electrical energy. Electricity comes from solar panels or a nuclear power plant. The methods of heating the working fluid are different, but in reality it is mainly used electric arc. It proved to be very reliable and withstands a large number of inclusions. Hydrogen is used as the working fluid in electric arc engines. With the help of an electric arc, hydrogen is heated to a very high temperature and it turns into plasma - an electrically neutral mixture of positive ions and electrons. The plasma outflow velocity from the thruster reaches 20 km/s. When scientists solve the problem of magnetic isolation of plasma from the walls of the engine chamber, then it will be possible to significantly increase the temperature of the plasma and bring the outflow velocity to 100 km/s. The first electric rocket engine was developed in the Soviet Union in the years. under the leadership (later he became the creator of engines for Soviet space rockets and an academician) in the famous gas dynamic laboratory (GDL). / 10 /

5.Other types of engines

There are also more exotic projects of nuclear rocket engines, in which the fissile material is in a liquid, gaseous or even plasma state, but the implementation of such designs at the current level of technology and technology is unrealistic. There are, while at the theoretical or laboratory stage, the following projects of rocket engines

Pulse nuclear rocket engines using the energy of explosions of small nuclear charges;

Thermonuclear rocket engines that can use an isotope of hydrogen as fuel. The energy efficiency of hydrogen in such a reaction is 6.8*1011 kJ/kg, that is, approximately two orders of magnitude higher than the productivity of nuclear fission reactions;

Solar sail engines - which use the pressure of sunlight (solar wind), the existence of which was experimentally proved by a Russian physicist back in 1899. By calculation, scientists have established that a device weighing 1 ton, equipped with a sail with a diameter of 500 m, can fly from Earth to Mars in about 300 days. However, the efficiency of a solar sail decreases rapidly with distance from the Sun.

6. Nuclear rocket engines

One of the main disadvantages of liquid propellant rocket engines is associated with the limited velocity of the outflow of gases. In nuclear rocket engines, it seems possible to use the colossal energy released during the decomposition of nuclear "fuel" to heat the working substance. The principle of operation of nuclear rocket engines is almost the same as the principle of operation of thermochemical engines. The difference lies in the fact that the working fluid is heated not due to its own chemical energy, but due to the "foreign" energy released during the intranuclear reaction. The working fluid is passed through a nuclear reactor, in which the fission reaction of atomic nuclei (for example, uranium) takes place, and at the same time it heats up. Nuclear rocket engines eliminate the need for an oxidizer and therefore only one liquid can be used. As a working fluid, it is advisable to use substances that allow the engine to develop a large traction force. Hydrogen satisfies this condition most fully, followed by ammonia, hydrazine, and water. The processes in which nuclear energy is released are divided into radioactive transformations, fission reactions of heavy nuclei, and fusion reactions of light nuclei. Radioisotope transformations are realized in the so-called isotopic energy sources. The specific mass energy (the energy that a substance weighing 1 kg can release) of artificial radioactive isotopes is much higher than that of chemical fuels. Thus, for 210Ро it is equal to 5*10 8 KJ/kg, while for the most energy efficient chemical fuel (beryllium with oxygen) this value does not exceed 3*10 4 KJ/kg. Unfortunately, it is not yet rational to use such engines on space launch vehicles. The reason for this is the high cost of the isotopic substance and the difficulty of operation. After all, the isotope releases energy constantly, even when it is transported in a special container and when the rocket is parked at the start. Nuclear reactors use more energy efficient fuel. Thus, the specific mass energy of 235U (the fissile isotope of uranium) is 6.75 * 10 9 kJ / kg, that is, approximately an order of magnitude higher than that of the 210Ро isotope. These engines can be "turned on" and "off", nuclear fuel (233U, 235U, 238U, 239Pu) is much cheaper than isotope. In such engines, not only water can be used as a working fluid, but also more efficient working substances - alcohol, ammonia, liquid hydrogen. The specific thrust of an engine with liquid hydrogen is 900 s. In the simplest scheme of a nuclear rocket engine with a reactor running on solid nuclear fuel, the working fluid is placed in a tank. The pump delivers it to the engine chamber. Sprayed with the help of nozzles, the working fluid comes into contact with the heat-producing nuclear fuel, heats up, expands and is ejected outward through the nozzle at high speed. Nuclear fuel in terms of energy reserves surpasses any other type of fuel. Then a natural question arises - why do installations on this fuel still have a relatively small specific thrust and a large mass? The fact is that the specific thrust of a solid-phase nuclear rocket engine is limited by the temperature of the fissile material, and the power plant emits strong ionizing radiation during operation, which has a harmful effect on living organisms. Biological protection against such radiation is of great importance and is not applicable to spacecraft. Practical development of nuclear rocket engines using solid nuclear fuel began in the mid-1950s in the Soviet Union and the United States, almost simultaneously with the construction of the first nuclear power plants. The work was carried out in an atmosphere of high secrecy, but it is known that such rocket engines have not yet received real use in astronautics. So far, everything has been limited to the use of isotopic sources of electricity of relatively low power on unmanned artificial satellites of the Earth, interplanetary spacecraft and the world-famous Soviet "lunar rover".

7. Nuclear jet engines, principle of operation, methods for obtaining an impulse in a nuclear rocket engine.

NRE got its name due to the fact that they create thrust through the use of nuclear energy, that is, the energy that is released as a result of nuclear reactions. In a general sense, these reactions mean any changes in the energy state of atomic nuclei, as well as the transformation of some nuclei into others, associated with the rearrangement of the structure of nuclei or a change in the number of elementary particles contained in them - nucleons. Moreover, nuclear reactions, as is known, can occur either spontaneously (i.e., spontaneously) or artificially induced, for example, when some nuclei are bombarded by others (or by elementary particles). Nuclear reactions of fission and fusion in terms of energy exceed chemical reactions by millions and tens of millions of times, respectively. This is explained by the fact that the chemical bond energy of atoms in molecules is many times less than the nuclear bond energy of nucleons in the nucleus. Nuclear energy in rocket engines can be used in two ways:

1. The released energy is used to heat the working fluid, which then expands in the nozzle, just like in a conventional rocket engine.

2. Nuclear energy is converted into electrical energy and then used to ionize and accelerate particles of the working fluid.

3. Finally, the impulse is created by the fission products themselves, formed in the process DIV_ADBLOCK265">

By analogy with the LRE, the original working fluid of the NRE is stored in a liquid state in the tank of the propulsion system and is supplied using a turbopump unit. Gas for the rotation of this unit, consisting of a turbine and a pump, can be produced in the reactor itself.

A diagram of such a propulsion system is shown in the figure.

There are many NREs with a fission reactor:

solid phase

gas phase

NRE with fusion reactor

Pulse YARD and others

Of all the possible types of NRE, the most developed are the thermal radioisotope engine and the engine with a solid-phase fission reactor. But if the characteristics of radioisotope NREs do not allow us to hope for their wide application in astronautics (at least in the near future), then the creation of solid-phase NREs opens up great prospects for astronautics. A typical NRE of this type contains a solid-phase reactor in the form of a cylinder with a height and diameter of about 1–2 m (if these parameters are close, the leakage of fission neutrons into the surrounding space is minimal).

The reactor consists of an active zone; a reflector surrounding this zone; governing bodies; power case and other elements. The core contains nuclear fuel - fissile material (enriched uranium), enclosed in fuel elements, and a moderator or diluent. The reactor shown in the figure is homogeneous - in it the moderator is part of the fuel elements, being homogeneously mixed with the fuel. The moderator can also be placed separately from the nuclear fuel. In this case, the reactor is called heterogeneous. Thinners (these may be, "for example, refractory metals- tungsten, molybdenum) are used to impart special properties to fissile substances.

The fuel elements of the solid-phase reactor are pierced with channels through which the working fluid of the NRE flows, gradually heating up. The channels have a diameter of about 1-3 mm, and their total area is 20-30% of the cross section of the core. The core is suspended by a special grid inside the power housing so that it can expand when the reactor is heated (otherwise it would collapse due to thermal stresses).

The core experiences high mechanical loads associated with the action of significant hydraulic pressure drops (up to several tens of atmospheres) from the flowing working fluid, thermal stresses and vibrations. The increase in the size of the core during heating of the reactor reaches several centimeters. The active zone and the reflector are placed inside a strong power housing, which perceives the pressure of the working fluid and the thrust created by the jet nozzle. The case is closed by a strong cover. It accommodates pneumatic, spring or electric mechanisms for driving the regulatory bodies, attachment points for the NRE to the spacecraft, flanges for connecting the NRE with the supply pipelines of the working fluid. A turbopump unit can also be located on the cover.

8 - Nozzle,

9 - Expanding nozzle,

10 - Selection of the working substance to the turbine,

11 - Power Corps,

12 - Control drum

13 - Turbine exhaust (used to control attitude and increase thrust),

14 - Ring drives control drums)

At the beginning of 1957, the final direction of the work of the Los Alamos Laboratory was determined, and a decision was made to build a graphite nuclear reactor with uranium fuel dispersed in graphite. The Kiwi-A reactor created in this direction was tested in 1959 on July 1st.

American solid-phase nuclear jet engine XE Prime on a test bench (1968)

In addition to the construction of the reactor, the Los Alamos Laboratory was in full swing on the construction of a special test site in Nevada, and also carried out a number of special orders from the US Air Force in related areas (development of individual TNRE units). On behalf of the Los Alamos Laboratory, all special orders for the manufacture of individual components were carried out by the firms: Aerojet General, the Rocketdyne division of North American Aviation. In the summer of 1958, all control of the Rover program passed from the US Air Force to the newly organized National Aeronautics and Space Administration (NASA). As a result of a special agreement between the AEC and NASA in the middle of the summer of 1960, the Office of Space Nuclear Engines was formed under the leadership of G. Finger, which led the Rover program in the future.

The results of six "hot tests" of nuclear jet engines were very encouraging, and in early 1961 a report on reactor flight tests (RJFT) was prepared. Then, in mid-1961, the Nerva project (the use of a nuclear engine for space rockets) was launched. Aerojet General was chosen as the general contractor, and Westinghouse as the subcontractor responsible for the construction of the reactor.

10.2 TNRD work in Russia

American" href="/text/category/amerikanetc/" rel="bookmark">Americans Russian scientists used the most economical and efficient tests of individual fuel elements in research reactors. Salyut", Design Bureau of Chemical Automation, IAE, NIKIET and NPO "Luch" (PNITI) to develop various projects of space nuclear rocket engines and hybrid nuclear power plants. Luch", MAI) were created YARD RD 0411 and a nuclear engine of minimum dimension RD 0410 thrust of 40 and 3.6 tons, respectively.

As a result, a reactor, a “cold” engine, and a bench prototype for testing on gaseous hydrogen were manufactured. Unlike the American one, with a specific impulse of no more than 8250 m/s, the Soviet TNRE, due to the use of more heat-resistant and advanced fuel elements and high temperature in the core, had this indicator equal to 9100 m/s and higher. The bench base for testing the TNRD of the joint expedition of NPO Luch was located 50 km southwest of the city of Semipalatinsk-21. She began working in 1962. In the years full-scale fuel elements of NRE prototypes were tested at the test site. At the same time, the exhaust gas entered the closed emission system. The bench complex for full-scale testing of nuclear engines "Baikal-1" is located 65 km south of the city of Semipalatinsk-21. From 1970 to 1988, about 30 "hot starts" of reactors were carried out. At the same time, the power did not exceed 230 MW at a hydrogen flow rate of up to 16.5 kg / s and its temperature at the reactor outlet of 3100 K. All launches were successful, accident-free, and according to plan.

Soviet TYARD RD-0410 - the only working and reliable industrial nuclear rocket engine in the world

Currently, such work at the landfill has been stopped, although the equipment is maintained in a relatively operable condition. The bench base of NPO Luch is the only experimental complex in the world where it is possible to test elements of NRE reactors without significant financial and time costs. It is possible that the resumption in the United States of work on TNRE for flights to the Moon and Mars as part of the Space Research Initiative program with the planned participation of specialists from Russia and Kazakhstan will lead to the resumption of the activities of the Semipalatinsk base and the implementation of the "Martian" expedition in the 2020s .

Main characteristics

Specific impulse on hydrogen: 910 - 980 sec(theor. up to 1000 sec).

· Speed of the expiration of a working body (hydrogen): 9100 - 9800 m/sec.

· Achievable thrust: up to hundreds and thousands of tons.

· Maximum working temperatures: 3000°С - 3700°С (short-term inclusion).

· Service life: up to several thousand hours (periodic activation). /5/

11.Device

The device of the Soviet solid-phase nuclear rocket engine RD-0410

1 - line from the tank of the working fluid

2 - turbopump unit

3 - control drum drive

4 - radiation protection

5 - control drum

6 - retarder

7 - fuel assembly

8 - reactor vessel

9 - fire bottom

10 - Nozzle cooling line

11- nozzle chamber

12 - nozzle

12. Working principle

The TNRD, by its principle of operation, is a high-temperature reactor-heat exchanger, into which a working fluid (liquid hydrogen) is introduced under pressure, and as it is heated to high temperatures (over 3000 ° C), it is ejected through a cooled nozzle. Heat recovery in the nozzle is very beneficial, as it allows much faster heating of hydrogen and, by utilizing a significant amount of thermal energy, to increase the specific impulse to 1000 sec (9100-9800 m/s).

Nuclear rocket engine reactor

MsoNormalTable">

working body

Density, g/cm3

Specific thrust (at the indicated temperatures in the heating chamber, °K), sec

0.071 (liquid)

0.682 (liquid)

1,000 (liquid)

no. data

(Note: The pressure in the heating chamber is 45.7 atm, expansion to a pressure of 1 atm with the chemical composition of the working fluid unchanged) /6/

15.Advantages

The main advantage of TNRD over chemical rocket engines is to obtain a higher specific impulse, a significant energy reserve, a compact system and the ability to obtain very high thrust (tens, hundreds and thousands of tons in vacuum. In general, the specific impulse achieved in vacuum is greater than that of spent two-component chemical rocket fuel (kerosene-oxygen, hydrogen-oxygen) by 3-4 times, and when operating at the highest heat intensity by 4-5 times.At present, in the USA and Russia there is considerable experience in the development and construction of such engines, and, if necessary (special programs space exploration) such engines can be produced in a short time and will have a reasonable cost. In the case of using TNRD to accelerate spacecraft in space, and subject to the additional use of perturbation maneuvers using the gravitational field of large planets (Jupiter, Uranus, Saturn, Neptune) achievable boundaries of the study of the solar Systems expand significantly, and the time required to reach distant planets is significantly reduced. In addition, TNRD can be successfully used for vehicles operating in low orbits of giant planets using their rarefied atmosphere as a working fluid, or for working in their atmosphere. /eight/

16. Disadvantages

The main disadvantage of TNRD is the presence of a powerful flux of penetrating radiation (gamma radiation, neutrons), as well as the removal of highly radioactive uranium compounds, refractory compounds with induced radiation, and radioactive gases with the working fluid. In this regard, TNRD is unacceptable for ground launches in order to avoid deterioration of the environmental situation at the launch site and in the atmosphere. /fourteen/

17. Improving the characteristics of the TJARD. Hybrid TNRD

Like any rocket or any engine in general, a solid-phase nuclear jet engine has significant limitations on the achievable critical characteristics. These restrictions represent the impossibility of the device (TNRD) to work in the temperature range exceeding the range of maximum operating temperatures of the engine structural materials. To expand the capabilities and significantly increase the main operating parameters of the TNRD, various hybrid schemes can be applied in which the TNRD plays the role of a source of heat and energy and additional physical methods for accelerating the working bodies are used. The most reliable, practically feasible, and having high characteristics in terms of specific impulse and thrust is a hybrid scheme with an additional MHD circuit (magnetohydrodynamic circuit) for accelerating the ionized working fluid (hydrogen and special additives). /13/

18. Radiation hazard from YARD.

A working NRE is a powerful source of radiation - gamma and neutron radiation. Without taking special measures, radiation can cause unacceptable heating of the working fluid and structure in the spacecraft, embrittlement of metal structural materials, destruction of plastic and aging of rubber parts, violation of the insulation of electrical cables, and failure of electronic equipment. Radiation can cause induced (artificial) radioactivity of materials - their activation.

At present, the problem of radiation protection of spacecraft with NRE is considered to be solved in principle. The fundamental issues related to the maintenance of nuclear rocket engines on test benches and launch sites have also been resolved. Although a working YARD poses a danger to service personnel"Already a day after the end of the work of the NRE, it is possible, without any personal protective equipment, to stay for several tens of minutes at a distance of 50 m from the NRE and even approach it. The simplest means of protection allow maintenance personnel to enter the working area of the NRE soon after testing.

The level of contamination of launch complexes and the environment, apparently, will not be an obstacle to the use of nuclear rocket engines on the lower stages of space rockets. The problem of radiation hazard to the environment and operating personnel is largely mitigated by the fact that hydrogen, used as a working fluid, is practically not activated when passing through the reactor. Therefore, the NRE jet is no more dangerous than the LRE jet. / 4 /

Conclusion

When considering the prospects for the development and use of NREs in astronautics, one should proceed from the achieved and expected characteristics of various types of NREs, from what they can give to astronautics, their application, and, finally, from the presence of a close connection between the NRE problem and the problem of energy supply in space and with the development of energy generally.

As mentioned above, of all the possible types of NRE, the most developed are the thermal radioisotope engine and the engine with a solid-phase fission reactor. But if the characteristics of radioisotope NREs do not allow us to hope for their wide application in astronautics (at least in the near future), then the creation of solid-phase NREs opens up great prospects for astronautics.

For example, a device with an initial mass of 40,000 tons (i.e., approximately 10 times greater than that of the largest modern launch vehicles) has been proposed, with 1/10 of this mass falling on the payload, and 2/3 on nuclear charges . If every 3 seconds one charge is blown up, then their supply will be enough for 10 days of continuous operation of the nuclear rocket engine. During this time, the device will accelerate to a speed of 10,000 km / s and in the future, after 130 years, it can reach the star Alpha Centauri.

Nuclear power plants have unique characteristics, which include practically unlimited energy intensity, independence of operation from the environment, non-susceptibility to external influences (cosmic radiation, meteorite damage, high and low temperatures, etc.). However maximum power nuclear radioisotope installations is limited to a value of the order of several hundred watts. This restriction does not exist for nuclear reactor power plants, which predetermines the profitability of their use during long-term flights of heavy spacecraft in near-Earth space, during flights to distant planets of the solar system, and in other cases.

The advantages of solid-phase and other NREs with fission reactors are most fully revealed in the study of such complex space programs as manned flights to the planets of the solar system (for example, during an expedition to Mars). In this case, an increase in the specific impulse of the RD makes it possible to solve qualitatively new problems. All these problems are greatly facilitated by the use of a solid-phase NRE with a specific impulse twice that of modern LREs. In this case, it also becomes possible to significantly reduce flight times.

Most likely, in the near future, solid-phase NREs will become one of the most common RDs. The solid-phase NRE can be used as vehicles for long-range flights, for example, to such planets as Neptune, Pluto, and even fly out of the Solar System. However, for flights to the stars, the NRE, based on the principles of fission, is not suitable. In this case, NREs or, more precisely, thermonuclear jet engines (TRDs) operating on the principle of fusion reactions and photonic jet engines (PRDs), in which the annihilation reaction of matter and antimatter is the source of momentum, are promising. However, most likely humanity to travel in interstellar space will use a different, different from the jet, method of movement.

In conclusion, I will rephrase Einstein's famous phrase - in order to travel to the stars, humanity must come up with something that would be comparable in complexity and perception to a nuclear reactor for a Neanderthal!

LITERATURE

Sources:

1. "Rockets and people. Book 4 Moon race" - M: Knowledge, 1999.
2. http://www. lpre. de/energomash/index. htm
3. Pervushin "Battle for the stars. Space confrontation" - M: knowledge, 1998.
4. L. Gilberg "Conquest of the sky" - M: Knowledge, 1994.
5. http://epizodsspace. *****/bibl/molodtsov
6. "Engine", "Nuclear engines for space vehicles", No. 5, 1999

7. "Engine", "Gas-phase nuclear engines for space vehicles",

No. 6, 1999
7.http://www. *****/content/numbers/263/03.shtml
8.http://www. lpre. de/energomash/index. htm
9. http://www. *****/content/numbers/219/37.shtml
10., Chekalin transport of the future.

Moscow: Knowledge, 1983.

11., Chekalin space exploration.- M.:

Knowledge, 1988.

12. "Energy - Buran" - a step into the future // Science and Life.-

13. Space technology. - M.: Mir, 1986.

14., Sergeyuk and commerce. - M .: APN, 1989.

15 .USSR in space. 2005.-M.: APN, 1989.

16. On the way to deep space // Energy. - 1985. - No. 6.

APPENDIX

Main characteristics of solid-phase nuclear jet engines

Manufacturer country	Engine	Thrust in vacuum, kN	specific impulse, sec	Project work, year
























	NERVA/Lox Mixed Cycle

Already at the end of this decade, a nuclear-powered spacecraft for interplanetary travel can be created in Russia. And this will dramatically change the situation both in the near-Earth space and on the Earth itself.

The nuclear power plant (NPP) will be ready for flight as early as 2018. This was announced by the director of the Keldysh Center, academician Anatoly Koroteev. “We must prepare the first sample (of a megawatt-class nuclear power plant. - Approx. "Expert Online") for flight design tests in 2018. Whether she will fly or not is another matter, there may be a queue, but she must be ready to fly, ”RIA Novosti reported him as saying. This means that one of the most ambitious Soviet-Russian projects in the field of space exploration is entering the phase of immediate practical implementation.

The essence of this project, whose roots go back to the middle of the last century, is this. Now flights to near-Earth space are carried out on rockets that move due to the combustion of liquid or solid fuel in their engines. In fact, this is the same engine as in the car. Only in a car, gasoline, burning, pushes the pistons in the cylinders, transferring its energy to the wheels through them. And in a rocket engine, burning kerosene or heptyl directly pushes the rocket forward.

Over the past half century, this rocket technology has been worked out all over the world to the smallest detail. But the rocket scientists themselves admit that. Improvement - yes, it is necessary. Trying to increase the carrying capacity of rockets from the current 23 tons to 100 and even 150 tons based on "improved" combustion engines - yes, you need to try. But this is a dead end in terms of evolution. " No matter how much rocket engine specialists all over the world work, the maximum effect that we get will be calculated in fractions of a percent. Roughly speaking, everything has been squeezed out of the existing rocket engines, be it liquid or solid propellant, and attempts to increase thrust and specific impulse are simply futile. Nuclear power plants, on the other hand, give an increase by several times. On the example of a flight to Mars - now you need to fly one and a half to two years there and back, but it will be possible to fly in two to four months ", - the ex-head of the Federal Space Agency of Russia once assessed the situation Anatoly Perminov.

Therefore, back in 2010, the then President of Russia, and now the Prime Minister Dmitry Medvedev an order was given by the end of this decade to create in our country a space transport and energy module based on a megawatt-class nuclear power plant. It is planned to allocate 17 billion rubles from the federal budget, Roskosmos and Rosatom for the development of this project until 2018. 7.2 billion of this amount was allocated to the State Atomic Energy Corporation Rosatom for the creation of a reactor plant (this is being done by the Dollezhal Research and Design Institute of Power Engineering), 4 billion - to the Keldysh Center for the creation of a nuclear power plant. 5.8 billion rubles is allocated to RSC Energia for the creation of a transport and energy module, that is, in other words, a rocket-ship.

Naturally, all this work is not done in a vacuum. From 1970 to 1988, only the USSR launched more than three dozen spy satellites into space, equipped with low-power nuclear power plants of the Buk and Topaz types. They were used to create an all-weather system for monitoring surface targets throughout the oceans and issuing target designation with transmission to weapon carriers or command posts - the Legenda marine space reconnaissance and target designation system (1978).

NASA and the American companies that produce spacecraft and their delivery vehicles have not been able during this time, although they tried three times, to create a nuclear reactor that would work stably in space. Therefore, in 1988, a ban on the use of spacecraft with nuclear power propulsion systems was carried out through the UN, and the production of satellites of the US-A type with nuclear power plants on board was discontinued in the Soviet Union.

In parallel, in the 60-70s of the last century, the Keldysh Center carried out active work on the creation of an ion engine (electroplasma engine), which is most suitable for creating a high-power propulsion system operating on nuclear fuel. The reactor generates heat, which is converted into electricity by the generator. With the help of electricity, the xenon inert gas in such an engine is first ionized, and then positively charged particles (positive xenon ions) are accelerated in an electrostatic field to a predetermined speed and create thrust, leaving the engine. This is the principle of operation of the ion engine, the prototype of which has already been created at the Keldysh Center.

« In the 1990s, we at the Keldysh Center resumed work on ion engines. Now a new cooperation should be created for such a powerful project. There is already a prototype of an ion engine, on which it is possible to work out the main technological and design solutions. And regular products still need to be created. We have a deadline - by 2018 the product should be ready for flight tests, and by 2015 the main development of the engine should be completed. Next - life tests and tests of the entire unit as a whole”, - noted last year the head of the department of electrophysics of the Research Center named after M.V. Keldysha, Professor, Faculty of Aerophysics and Space Research, Moscow Institute of Physics and Technology Oleg Gorshkov.

What is the practical benefit of Russia from these developments? This benefit far exceeds the 17 billion rubles that the state intends to spend until 2018 on the creation of a launch vehicle with a nuclear power plant on board with a capacity of 1 MW. First, it is a sharp expansion of the possibilities of our country and humanity in general. A spacecraft with a nuclear engine gives real opportunities for people to commit to other planets. Now many countries have such ships. They resumed in the United States in 2003, after the Americans got two samples of Russian satellites with nuclear power plants.

However, despite this, a member of the NASA special commission on manned flights Edward Crowley, for example, he believes that a ship for an international flight to Mars should have Russian nuclear engines. " Russian experience in the development of nuclear engines is in demand. I think Russia has a very great experience both in the development of rocket engines and in nuclear technology. She also has extensive experience in human adaptation to space conditions, since Russian cosmonauts made very long flights. “, Crowley told reporters last spring after a lecture at Moscow State University on American plans for manned space exploration.

Secondly, such ships make it possible to sharply intensify activity in near-Earth space and provide a real opportunity to start the colonization of the Moon (there are already construction projects on the Earth’s satellite nuclear power plants). « The use of nuclear propulsion systems is considered for large manned systems and not for small spacecraft that can fly on other types of installations using ion propulsion or solar wind energy. It is possible to use nuclear power plants with ion engines on an interorbital reusable tug. For example, to carry cargo between low and high orbits, to fly to asteroids. You can create a reusable lunar tug or send an expedition to Mars", - says Professor Oleg Gorshkov. Such ships are dramatically changing the economics of space exploration. According to the calculations of RSC Energia specialists, a nuclear-powered launch vehicle reduces the cost of launching a payload into a circumlunar orbit by more than two times compared to liquid-propellant rocket engines.

Thirdly, these are new materials and technologies that will be created during the implementation of this project and then introduced into other industries - metallurgy, mechanical engineering, etc. That is, this is one of such breakthrough projects that can really push forward both the Russian and the world economy.

Atomic rocket. Nuclear-powered cruise missile