Technical details: nuclear-powered rocket. Nuclear engines for spacecraft

Alexander Losev

The rapid development of rocket and space technology in the 20th century was due to military-strategic, political and, to a certain extent, ideological goals and the interests of two superpowers - the USSR and the USA, and all state space programs were a continuation of their military projects, where main task there was a need to ensure defense capability and strategic parity with a potential enemy. The cost of creating equipment and operating costs were not of fundamental importance then. Enormous resources were allocated to the creation of launch vehicles and spacecraft, and the 108-minute flight of Yuri Gagarin 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 seen 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 world the superiority of the Western economic system and ideological concepts.
In the 90s, the main political tasks of previous years lost relevance, bloc confrontation was replaced by globalization, pragmatism prevailed in the world, so the majority space programs was curtailed or postponed, only the ISS remained as a legacy from the large-scale projects of the past. In addition, Western democracy has made all expensive government programs dependent on electoral cycles.
Voter support, necessary to gain or maintain power, forces politicians, parliaments and governments to lean towards populism and solve short-term problems, so spending on space exploration is reduced year after year.
Most of the fundamental discoveries were made in the first half of the twentieth century, and nowadays science and technology have reached certain limits, moreover, the popularity of scientific knowledge has decreased all over the world, and the quality of teaching mathematics, physics and others has deteriorated. natural sciences. This has become the reason for the stagnation, including in the space sector, of the last two decades.
But now it is becoming obvious that the world is approaching the end of another technological cycle based on the discoveries of the last century. Therefore, any power that will possess fundamentally new promising technologies at the time of change in the global technological structure will automatically secure world leadership for at least the next fifty years.

Fundamental design of a nuclear propulsion engine with hydrogen as a working fluid

This is realized both in the United States, which has set a course for the revival of American greatness in all spheres of activity, and in China, which is challenging American hegemony, and in the European Union, which is trying with all its might to maintain its weight in the global economy.
They have an industrial policy and are seriously engaged in the development of their own scientific, technical and production potential, and the space sphere can become the best testing ground for testing new technologies and for proving or refuting scientific hypotheses that can lay the foundation for the creation of fundamentally different, more advanced technology of the future.
And it is quite natural to expect that the United States will be the first country to resume deep space exploration projects with the goal of creating unique innovative technologies both in the field of weapons, transport and construction materials, and in biomedicine and telecommunications
True, not even the United States is guaranteed success in creating revolutionary technologies. Eat high risk find yourself in a dead end when improving half a century old rocket engines based on chemical fuel, as Elon Musk’s SpaceX is doing, or creating life support systems for long flights similar to those already implemented on the ISS.
Can Russia, whose stagnation in the space sector is becoming more noticeable every year, make a leap in the race for future technological leadership to remain in the club of superpowers rather than on the list of developing countries?
Yes, of course, Russia can, and moreover, a noticeable step forward has already been made in nuclear energy and in nuclear rocket engine technologies, 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 connected, 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 fuel accelerators and liquid rocket engines, in their combustion chambers the fuel components (fuel and oxidizer) enter into an exothermic physical and chemical combustion reaction, forming a jet stream that ejects tons of substance from the engine nozzle every second. The kinetic energy of the jet's working fluid is converted into a reactive force sufficient to propel the rocket. The specific impulse (the ratio of the thrust generated to the mass of the fuel used) of such chemical engines depends on the fuel components, the pressure and temperature in the combustion chamber, as well as 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 the molecular mass of the gas, the higher the specific impulse, and therefore the efficiency of the engine. Specific impulse is a quantity of motion and is usually measured in meters per second, just like speed.
In chemical engines, the highest specific impulse is given by oxygen-hydrogen and fluorine-hydrogen fuel mixtures (4500–4700 m/s), but the most popular (and convenient to operate) have become rocket engines running on kerosene and oxygen, for example the Soyuz and Musk's Falcon missiles, as well as engines using unsymmetrical dimethylhydrazine (UDMH) with an oxidizer in the form of a mixture of nitrogen tetroxide and nitric acid(Soviet and Russian Proton, French Ariane, American Titan). Their efficiency is 1.5 times lower than that of hydrogen fuel engines, but an impulse of 3000 m/s and power are quite enough to make it economically profitable to launch tons of payload into near-Earth orbits.
But flights to other planets require much larger size spaceships than all that have been created by mankind previously, including the modular ISS. In these ships, it is necessary to ensure the long-term autonomous existence of the crews, and a certain supply of fuel and service life of the main engines and engines for maneuvers and orbit correction, to 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 the return of the expedition to Earth.
The accumulated engineering knowledge and chemical energy of engines make it possible to return to the Moon and reach Mars, so there is a high probability that humanity will visit the Red Planet in the next decade.
If we rely only on existing space technologies, then the minimum mass of the 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 launch vehicles for their launch 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 in orbit weighing up to 500 tons. A flight on an interplanetary ship with chemical rocket engines will require from 8 months to 1 year in one direction only, because it will be necessary to perform gravity maneuvers, using the gravitational force of the planets and a colossal supply of fuel to additionally accelerate the ship.
But using the chemical energy of rocket engines, humanity will not fly further than the orbit of Mars or Venus. We need different flight speeds of spacecraft and other more powerful energy of movement.

Modern design of a nuclear rocket engine Princeton Satellite Systems

To explore deep space, it is necessary to significantly increase the thrust-to-weight ratio and efficiency of a rocket engine, and therefore increase its specific impulse and service life. And to do this, it is necessary to heat a gas or working fluid substance with 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, heated 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 with 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 will not be required, and light hydrogen gas can be used as a substance that creates jet thrust; we know that the lower the molecular mass of the gas, the higher the impulse, and this will greatly reduce the mass of the rocket with better performance engine power.
A nuclear engine will be better than a conventional one, since in the reactor zone the light gas can be heated to temperatures exceeding 9 thousand degrees Kelvin, and the jet of such superheated gas will provide a much higher specific impulse than conventional chemical engines can provide. But this is in theory.
The danger is not even that during the launch of a launch vehicle with such a nuclear installation, an accident could occur. radioactive contamination atmosphere and space around the launch pad, the main problem is that at high temperatures the engine itself, along with the spacecraft, can melt. 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 human flight into space, and almost simultaneously in both the USSR and the USA, and the very idea of ​​​​using nuclear reactors to heat the working substance in rocket engine was born along with the first rectors in the mid-40s, that is, more than 70 years ago.
In our country, the initiator of the creation of nuclear propulsion was the thermal physicist Vitaly Mikhailovich Ievlev. 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 install them on ballistic missiles. The development was carried out by the leading defense design bureaus of the Soviet Union, as well as research institutes NIITP, CIAM, IAE, VNIINM.
The Soviet nuclear engine RD-0410 was assembled in the mid-60s at the Voronezh Chemical Automatics Design Bureau, 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 a “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 released through the channel nozzles, thus converting thermal energy into kinetic energy and creating a specific impulse of 9100 m/s.
In the USA, the nuclear propulsion engine 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 and 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 nuclear engines (nuclear fuel based on uranium carbides was in the solid state in the reactor), and their operating temperature was in the range of 2300–3100K.
To increase the temperature of the core without the risk of explosion or melting of the reactor walls, it is necessary to create such nuclear reaction conditions under which the fuel (uranium) turns into a gaseous state or turns into plasma and is held inside the reactor by 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 at a very high speed through the nozzle channel.
This type of engine is called a gas-phase nuclear propulsion engine. The temperatures of the gaseous uranium fuel in such nuclear engines can range from 10 thousand to 20 thousand degrees Kelvin, and the specific impulse can reach 50,000 m/s, which is 11 times higher than that of the most efficient chemical rocket engines.
Creation and use in space technology gas-phase nuclear propulsion engines of open and closed types- this 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 research on the gas-phase nuclear propulsion project began in the USSR in 1957 at the Research Institute of Thermal Processes (National Research Center named after M. V. Keldysh), and the 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 CPSU Central Committee and the Council of Ministers of the USSR.
The development of gas-phase nuclear propulsion engines was carried out in the Soviet Union for two decades, but, unfortunately, was never completed due to insufficient funding and the need for additional basic research in the field of thermodynamics of nuclear fuel and hydrogen plasma, neutron physics and magnetic hydrodynamics.
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, and the accumulation of uranium fission products , selection of chemically resistant construction materials, etc.
And when the Energia launch vehicle began to be created for the Soviet Mars-94 program for 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 technology 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 brought back, and lost knowledge cannot be restored. A lot will have to be created anew.
But space nuclear power is not limited only to the sphere of solid- and gas-phase nuclear propulsion engines. Electrical energy can be used to create a heated flow of matter in a jet engine. This idea was first expressed by Konstantin Eduardovich Tsiolkovsky back in 1903 in his work “Exploration of world spaces using jet 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 the head of NPO Energia.
The operating principles 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 ejected from the nozzle in the same way as in a nuclear rocket engine.
• electrostatic engines (colloidal and ionic), in which the working substance is first ionized, 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. Electrostatic engines also include stationary plasma engines.
• magnetoplasma and magnetodynamic rocket engines. There, the gas plasma is accelerated due to the Ampere force in the magnetic and electric fields intersecting perpendicularly.
• pulse rocket engines, which use the energy of gases resulting from the evaporation of a working fluid in an electric discharge.

The advantage of these electric rocket engines is the low consumption of the working fluid, efficiency up to 60% and high particle flow speed, which can significantly reduce the mass of the spacecraft, but there is also a disadvantage - low thrust density, and therefore low power, as well as the high cost of the working fluid (inert gases or vapors of alkali metals) to create 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 spacecraft since the mid-60s, but due to their low power they were used mainly as orbit correction engines.
From 1968 to 1988, the USSR launched a whole series of Cosmos satellites with nuclear installations on board. The types of reactors were named: “Buk”, “Topaz” and “Yenisei”.
The Yenisei project reactor had a thermal power of up to 135 kW and an electrical power of about 5 kW. The coolant was a sodium-potassium melt. This project was closed in 1996.
A real propulsion rocket motor requires a very powerful source of energy. 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 a 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 gas-phase nuclear propulsion is a topic for future decades that will have to be returned to after fundamental research, then its today’s alternative is a megawatt-class nuclear power propulsion system (NPPU), and it has already been created by Rosatom and Roscosmos enterprises since 2009.
NPO Krasnaya Zvezda, which is currently the world's only developer and manufacturer of space nuclear power plants, as well as the Research Center named after A. M. V. Keldysh, NIKIET im. N. A. Dollezhala, Research Institute NPO “Luch”, “Kurchatov Institute”, IRM, IPPE, RIAR and NPO Mashinostroeniya.
The nuclear power propulsion system includes a high-temperature gas-cooled fast neutron nuclear reactor with a turbomachine system for converting thermal energy into electrical energy, a system of refrigerator-emitters for removing excess heat into space, an instrumentation compartment, a block of sustainer plasma or ion electric motors, and a container for accommodating the payload. .
In a power propulsion system, 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 a nuclear propulsion engine, which makes the design more reliable and safe, and therefore suitable for manned space flight.
It is planned that the 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 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 installation makes it safe for people and the environment on Earth.
In 2014, the first standard design fuel element (fuel element) for this nuclear electric propulsion system was assembled at JSC Mashinostroitelny Zavod in Elektrostal, and in 2016 tests of a reactor core basket simulator were carried out.
Now (in 2017) work is underway on the production of structural elements of the installation and testing of components and assemblies on mock-ups, as well as autonomous testing of turbomachine energy conversion systems and prototype power units. Completion of the work is scheduled for the end of next 2018, however, since 2015, the backlog of 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 not only for future projects for the exploration of the Solar system, but also for terrestrial and extraterrestrial energy. Space nuclear power plants can be used to create systems for remote transmission of electricity to Earth or to space modules using electromagnetic radiation. And this will also become an advanced technology of the future, where our country will have a leading position.
Based on the plasma electric motors being developed, powerful propulsion systems will be created for long-distance human flights into space and, first of all, for the exploration of Mars, the orbit of which can be reached in just 1.5 months, and not in more than a year, as when using conventional chemical jet engines .
And the future always begins with a revolution in energy. And nothing else. Energy is primary and it is the amount 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 of 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 planet's population uses for its needs. Thus, type I civilization uses all available resources available on the planet; Type II civilization - receives the energy of its star in whose system it is located; and a type III civilization uses the available energy of its galaxy. Humanity has not yet matured to type I civilization on this scale. We use only 0.16% of the total potential energy reserve of 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 to space, but also to future economic prosperity.
And, perhaps, the only option for Russia in the scientific and technical sphere is to now make a revolutionary breakthrough in nuclear space technologies in order to overcome the many-year lag behind the leaders in one “leap” and be right at the origins of a new technological revolution in the next cycle of development of human civilization. Such a unique chance falls to a particular country only once every few centuries.
Unfortunately, Russia, which has not paid enough attention to fundamental sciences and the quality of higher and secondary education over the past 25 years, risks losing this chance forever if the program is curtailed and a new generation of researchers does not replace the current scientists and engineers. 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 now urgently necessary to begin training specialists capable of responding to these challenges and creating something fundamentally new.
There are only about 10 years to transform Russia into a global 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) systematic views on the picture of the world, scientific fundamentality and ideological integrity.
As for the current stagnation in the space industry, this is not scary. The physical principles on which modern space technologies are based will be in demand for a long time in the conventional satellite services sector. Let us remember that humanity used the 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 innovation and a change in technological structures, which ultimately changed both the world economy and politics. The main thing is to be at the origins of these changes.

A safe method of using nuclear energy in space was invented in the USSR, and work is now underway to create a nuclear installation based on it, he said general manager State scientific center Russian Federation "Research Center named after Keldysh", academician Anatoly Koroteev.

“Now the institute is actively working in this direction in large cooperation between Roscosmos and Rosatom enterprises. And I hope that in due time we will get a positive effect here,” A. Koroteev said at the annual “Royal Readings” at the Bauman Moscow State Technical University on Tuesday.

According to him, the Keldysh Center has invented a scheme for the safe use of nuclear energy in outer space, which allows you to do without emissions and operates in a closed circuit, which makes the installation safe even if it fails and falls to Earth.

“This scheme greatly reduces the risk of using nuclear energy, especially considering that one of the fundamental points is the operation of this system in orbits above 800-1000 km. Then, in case of failure, the “flashing” time is such that it makes it safe for these elements to return to Earth after a long period of time,” the scientist clarified.

A. Koroteev said that previously the USSR had already used spacecraft powered by nuclear energy, but they were potentially dangerous for the Earth, and subsequently had to be abandoned. “The USSR used nuclear energy in space. There were 34 spacecraft with nuclear energy in space, of which 32 were Soviet and two American,” the academician recalled.

According to him, the nuclear installation being developed in Russia will be made lighter through the use of a frameless cooling system, in which the nuclear reactor coolant will circulate directly in outer space without a pipeline system.

But back in the early 1960s, designers considered nuclear rocket engines as the only real alternative for traveling to other planets in the solar system. Let's find out the history of this issue.

The competition between the USSR and the USA, including in space, was going on at that time in full swing, engineers and scientists entered the race to create a nuclear propulsion engine, and the military also initially supported the nuclear rocket engine project. At first, the task seemed very simple - you just need to make a reactor designed to be cooled with hydrogen rather than water, attach a nozzle to it, and - forward to Mars! The Americans were going to Mars ten years after the Moon and could not even imagine that astronauts would ever reach it without nuclear engines.

The Americans very quickly built the first prototype reactor and already tested it in July 1959 (they were called KIWI-A). These tests merely showed that the reactor could be used to heat hydrogen. The reactor design - with unprotected uranium oxide fuel - was not suitable for high temperatures, and the hydrogen only heated up to one and a half thousand degrees.

As experience was gained, the design of reactors for nuclear rocket engines - NRE - became more complex. The uranium oxide was replaced with a more heat-resistant carbide, in addition it was coated with niobium carbide, but when trying to reach the design temperature, the reactor began to collapse. Moreover, even in the absence of macroscopic destruction, diffusion of uranium fuel into cooling hydrogen occurred, and mass loss reached 20% within five hours of reactor operation. A material capable of operating at 2700-3000 0 C and resisting destruction by hot hydrogen has never been found.

Therefore, the Americans decided to sacrifice efficiency and included specific impulse in the flight engine design (thrust in kilograms of force achieved with the release of one kilogram of working fluid mass every second; the unit of measurement is a second). 860 seconds. This was twice the corresponding figure for oxygen-hydrogen engines of that time. But when the Americans began to succeed, interest in manned flights had already fallen, the Apollo program was curtailed, and in 1973 the NERVA project (that was the name of the engine for a manned expedition to Mars) was finally closed. Having won the lunar race, the Americans did not want to organize a Martian race.

But the lesson learned from the dozens of reactors built and the dozens of tests conducted was that American engineers got too carried away with full-scale nuclear testing rather than working out key elements without involving nuclear technology where it could be avoided. And where it is not possible, use smaller stands. The Americans ran almost all the reactors at full power, but were unable to reach the design temperature of hydrogen - the reactor began to collapse earlier. In total, from 1955 to 1972, $1.4 billion was spent on the nuclear rocket engine program - approximately 5% of the cost of the lunar program.

Also in the USA, the Orion project was invented, which combined both versions of the nuclear propulsion system (jet and pulse). This was done in the following way: small nuclear charges with a capacity of about 100 tons of TNT were ejected from the tail of the ship. Metal discs were fired after them. At a distance from the ship, the charge was detonated, the disk evaporated, and the substance scattered into different sides. Part of it fell into the reinforced tail section of the ship and moved it forward. A small increase in thrust should have been provided by the evaporation of the plate taking the blows. The unit cost of such a flight should have been only 150 then dollars per kilogram of payload.

It even went as far as testing: experience showed that movement with the help of successive impulses is possible, as is the creation of a stern plate of sufficient strength. But the Orion project was closed in 1965 as unpromising. However, this is so far the only existing concept that can allow expeditions at least across the solar system.

In the first half of the 1960s, Soviet engineers viewed the expedition to Mars as a logical continuation of the then-developed program of manned flight to the Moon. In the wake of the enthusiasm caused by the USSR's priority in space, even such extremely complex problems were assessed with increased optimism.

One of the most important problems was (and remains to this day) the problem of power supply. It was clear that liquid-propellant rocket engines, even promising oxygen-hydrogen ones, could, in principle, provide a manned flight to Mars, then only with huge launch masses of the interplanetary complex, with a large number of dockings of individual blocks in the assembly low-Earth orbit.

In search of optimal solutions, scientists and engineers turned to nuclear energy, gradually taking a closer look at this problem.

In the USSR, research on the problems of using nuclear energy in rocket and space technology began in the second half of the 50s, even before the launch of the first satellites. Small groups of enthusiasts emerged in several research institutes with the goal of creating rocket and space nuclear engines and power plants.

The designers of OKB-11 S.P. Korolev, together with specialists from NII-12 under the leadership of V.Ya. Likhushin, considered several options for space and combat (!) rockets equipped with nuclear rocket engines (NRE). Water and liquefied gases - hydrogen, ammonia and methane - were evaluated as the working fluid.

The prospect was promising; gradually the work found understanding and financial support in the government of the USSR.

Already the very first analysis showed that among the many possible schemes space nuclear power propulsion systems (NPPU) have the greatest prospects for three:

• with a solid-phase nuclear reactor;
• with a gas-phase nuclear reactor;
• electronuclear rocket propulsion systems.

The schemes were fundamentally different; For each of them, several options were outlined for the development of theoretical and experimental work.

The closest to implementation seemed to be a solid-phase nuclear propulsion engine. The impetus for the development of work in this direction was provided by similar developments carried out in the USA since 1955 under the ROVER program, as well as the prospects (as it seemed then) of creating a domestic intercontinental manned bomber aircraft with a nuclear propulsion system.

A solid-phase nuclear propulsion engine operates as a direct-flow engine. Liquid hydrogen enters the nozzle part, cools the reactor vessel, fuel assemblies (FA), moderator, and then turns around and enters the FA, where it heats up to 3000 K and is thrown into the nozzle, accelerating to high speeds.

The operating principles of the nuclear propulsion system were not in doubt. However, its design (and characteristics) largely depended on the “heart” of the engine – the nuclear reactor and were determined, first of all, by its “filling” – the core.

The developers of the first American (and Soviet) nuclear propulsion engines advocated a homogeneous reactor with a graphite core. The work of the search group on new types of high-temperature fuels, created in 1958 in laboratory No. 21 (headed by G.A. Meerson) of NII-93 (director A.A. Bochvar), proceeded somewhat separately. Influenced by the ongoing work on an aircraft reactor (a honeycomb of beryllium oxide) at that time, the group made attempts (again exploratory) to obtain materials based on silicon and zirconium carbide that were resistant to oxidation.

According to the memoirs of R.B. Kotelnikov, an employee of NII-9, in the spring of 1958, the head of laboratory No. 21 had a meeting with a representative of NII-1, V.N. Bogin. He said that as the main material for the fuel elements (fuel rods) of the reactor in their institute (by the way, at that time the leading one in the rocket industry; head of the institute V.Ya. Likhushin, scientific director M.V. Keldysh, head of the laboratory V.M. .Ievlev) use graphite. In particular, they have already learned how to apply coatings to samples to protect them from hydrogen. NII-9 proposed to consider the possibility of using UC-ZrC carbides as the basis for fuel elements.

After a short time, another customer for fuel rods appeared - the Design Bureau of M.M. Bondaryuk, which ideologically competed with NII-1. If the latter stood for a multi-channel all-block design, then the Design Bureau of M.M. Bondaryuk headed for a collapsible plate version, focusing on the ease of machining of graphite and not being embarrassed by the complexity of the parts - millimeter-thick plates with the same ribs. Carbides are much more difficult to process; at that time it was impossible to make parts such as multi-channel blocks and plates from them. It became clear that it was necessary to create some other design that would correspond to the specifics of carbides.

At the end of 1959 - beginning of 1960, the decisive condition for NRE fuel rods was found - a rod type core, satisfying the customers - the Likhushin Research Institute and the Bondaryuk Design Bureau. The design of a heterogeneous reactor on thermal neutrons was justified as the main one for them; its main advantages (compared to the alternative homogeneous graphite reactor) are:

• it is possible to use a low-temperature hydrogen-containing moderator, which makes it possible to create nuclear propulsion engines with high mass perfection;
• it is possible to develop a small-sized prototype of a nuclear propulsion engine with a thrust of about 30...50 kN s high degree continuity for engines and nuclear power plants of the next generation;
• it is possible to widely use refractory carbides in fuel rods and other parts of the reactor structure, which makes it possible to maximize the heating temperature of the working fluid and provide an increased specific impulse;
• it is possible to autonomously test, element by element, the main components and systems of the nuclear propulsion system (NPP), such as fuel assemblies, moderator, reflector, turbopump unit (TPU), control system, nozzle, etc.; this allows testing to be carried out in parallel, reducing the amount of expensive complex testing of the power plant as a whole.

Around 1962–1963 Work on the nuclear propulsion problem was headed by NII-1, which has a powerful experimental base and excellent personnel. They only lacked uranium technology, as well as nuclear scientists. With the involvement of NII-9, and then IPPE, a cooperation was formed, which took as its ideology the creation of a minimum thrust (about 3.6 tf), but “real” summer engine with a “direct-flow” reactor IR-100 (test or research, 100 MW, chief designer - Yu.A. Treskin). Supported by government regulations, NII-1 built electric arc stands that invariably amazed the imagination - dozens of 6-8 m high cylinders, huge horizontal chambers with a power of over 80 kW, armored glass in boxes. Meeting participants were inspired by colorful posters with flight plans to the Moon, Mars, etc. It was assumed that in the process of creating and testing the nuclear propulsion engine, design, technological, and physical issues would be resolved.

According to R. Kotelnikov, the matter, unfortunately, was complicated by the not very clear position of the rocket scientists. The Ministry of General Engineering (MOM) had great difficulties in financing the testing program and the construction of the test bench base. It seemed that the IOM did not have the desire or capacity to advance the NRD program.

By the end of the 1960s, support for NII-1's competitors - IAE, PNITI and NII-8 - was much more serious. The Ministry of Medium Engineering ("nuclear scientists") actively supported their development; the IVG “loop” reactor (with a core and rod-type central channel assemblies developed by NII-9) eventually came to the fore by the beginning of the 70s; testing of fuel assemblies began there.

Now, 30 years later, it seems that the IAE line was more correct: first - a reliable “earthly” loop - testing of fuel rods and assemblies, and then the creation of a flight nuclear propulsion engine of the required power. But then it seemed that it was possible to very quickly make a real engine, albeit a small one... However, since life has shown that there was no objective (or even subjective) need for such an engine (to this we can also add that the seriousness of the negative aspects of this direction, for example international agreements about nuclear devices in space, was at first greatly underestimated), then accordingly it turned out to be more correct and productive fundamental program, whose goals were not narrow and specific.

On July 1, 1965, the preliminary design of the IR-20-100 reactor was reviewed. The culmination was the release of the technical design of the IR-100 fuel assemblies (1967), consisting of 100 rods (UC-ZrC-NbC and UC-ZrC-C for the inlet sections and UC-ZrC-NbC for the outlet). NII-9 was ready to produce a large batch of core elements for the future IR-100 core. The project was very progressive: after about 10 years, practically without significant changes, it was used in the area of ​​​​the 11B91 apparatus, and even now all the main solutions are preserved in assemblies of similar reactors for other purposes, with a completely different degree of calculation and experimental justification.

The “rocket” part of the first domestic nuclear RD-0410 was developed at the Voronezh Design Bureau of Chemical Automation (KBHA), the “reactor” part (neutron reactor and radiation safety issues) - by the Institute of Physics and Energy (Obninsk) and the Kurchatov Institute atomic energy.

KBHA is known for its work in the field of liquid propellant engines for ballistic missiles, spacecraft and launch vehicles. About 60 samples were developed here, 30 of which were brought to mass production. By 1986, KBHA had created the country's most powerful single-chamber oxygen-hydrogen engine RD-0120 with a thrust of 200 tf, which was used as a propulsion engine in the second stage of the Energia-Buran complex. Nuclear RD-0410 was created jointly with many defense enterprises, design bureaus and research institutes.

According to the accepted concept, liquid hydrogen and hexane (an inhibitory additive that reduces the hydrogenation of carbides and increases the life of fuel elements) were supplied using a TNA into a heterogeneous thermal neutron reactor with fuel assemblies surrounded by a zirconium hydride moderator. Their shells were cooled with hydrogen. The reflector had drives for rotating the absorption elements (boron carbide cylinders). The pump included a three-stage centrifugal pump and a single-stage axial turbine.

In five years, from 1966 to 1971, the foundations of reactor-engine technology were created, and a few years later a powerful experimental base called “expedition No. 10” was put into operation, subsequently the experimental expedition of NPO “Luch” at the Semipalatinsk nuclear test site .
Particular difficulties were encountered during testing. It was impossible to use conventional stands for launching a full-scale nuclear rocket engine due to radiation. It was decided to test the reactor at the nuclear test site in Semipalatinsk, and the “rocket part” at NIIkhimmash (Zagorsk, now Sergiev Posad).

To study intra-chamber processes, more than 250 tests were performed on 30 “cold engines” (without a reactor). The combustion chamber of the oxygen-hydrogen rocket engine 11D56 developed by KBKhimmash (chief designer - A.M. Isaev) was used as a model heating element. The maximum operating time was 13 thousand seconds with an declared resource of 3600 seconds.

To test the reactor at the Semipalatinsk test site, two special shafts with underground service premises were built. One of the shafts was connected to an underground reservoir for compressed hydrogen gas. The use of liquid hydrogen was abandoned for financial reasons.

In 1976, the first power start-up of the IVG-1 reactor was carried out. At the same time, a stand was created at the OE to test the “propulsion” version of the IR-100 reactor, and a few years later it was tested at different powers (one of the IR-100s was subsequently converted into a low-power materials science research reactor, which is still in operation today).

Before the experimental launch, the reactor was lowered into the shaft using a surface-mounted gantry crane. After starting the reactor, hydrogen entered the “boiler” from below, heated up to 3000 K and burst out of the shaft in a fiery stream. Despite the insignificant radioactivity of the escaping gases, it was not allowed to be outside within a radius of one and a half kilometers from the test site during the day. It was impossible to approach the mine itself for a month. A one and a half kilometer underground tunnel led from the safe zone first to one bunker, and from there to another, located near the mines. The specialists moved along these unique “corridors.”

Ievlev Vitaly Mikhailovich

The results of experiments carried out with the reactor in 1978–1981 confirmed the correctness of the design solutions. In principle, the YARD was created. All that remained was to connect the two parts and conduct comprehensive tests.

Around 1985, RD-0410 (according to a different designation system 11B91) could have made its first space flight. But for this it was necessary to develop an accelerating unit based on it. Unfortunately, this work was not ordered to any space design bureau, and there are many reasons for this. The main one is the so-called Perestroika. Rash steps led to the fact that the entire space industry instantly found itself “in disgrace” and in 1988, work on nuclear propulsion in the USSR (then the USSR still existed) was stopped. This happened not because of technical problems, but for momentary ideological considerations. And in 1990, the ideological inspirer of nuclear-powered rocket engines programs in the USSR, Vitaly Mikhailovich Ievlev, died...

What major successes have the developers achieved in creating the “A” nuclear power propulsion system?

More than one and a half dozen full-scale tests were carried out on the IVG-1 reactor, and the following results were obtained: maximum hydrogen temperature - 3100 K, specific impulse - 925 sec, specific heat release up to 10 MW/l, total resource more than 4000 sec with consecutive 10 reactor starts. These results significantly exceed American achievements in graphite zones.

It should be noted that during the entire period of NRE testing, despite the open exhaust, the yield of radioactive fission fragments did not exceed permissible standards either at the test site or outside it and was not registered on the territory of neighboring states.

The most important result of the work was the creation of domestic technology for such reactors, the production of new refractory materials, and the fact of creating a reactor-engine gave rise to a number of new projects and ideas.

Although the further development of such nuclear powered engines was suspended, the achievements obtained are unique not only in our country, but also in the world. This has been confirmed repeatedly in recent years on international symposiums on space energy, as well as at meetings of domestic and American specialists (at the latter it was recognized that the IVG reactor stand is the only operational test apparatus in the world today, which can play an important role in the experimental testing of fuel assemblies and nuclear power plants).

sources
http://newsreaders.ru
http://marsiada.ru
http://vpk-news.ru/news/14241

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A rocket engine in which the working fluid is either a substance (for example, hydrogen) heated by the energy released during a nuclear reaction or radioactive decay, or directly the products of these reactions. Distinguish... ... Big Encyclopedic Dictionary

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nuclear rocket engine- branduolinis raketinis variklis statusas T sritis Gynyba apibrėžtis Raketinis variklis, kuriame reaktyvinė trauka sudaroma vykstant branduolinei arba termobranduolinei reakcijai. Branduoliniams raketiniams varikliams sudaroma kur kas didesnė… … Artilerijos terminų žodynas

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Often in general educational publications about astronautics, the difference between a nuclear rocket engine (NRE) and a nuclear rocket electric propulsion system (NRE) is not distinguished. However, these abbreviations hide not only the difference in the principles of converting nuclear energy into rocket thrust, but also a very dramatic history of the development of astronautics.

The drama of the story lies in the fact that if those stopped mainly by economic reasons Since research into nuclear propulsion and nuclear propulsion in both the USSR and the USA continued, human flights to Mars would have long ago become commonplace.

It all started with atmospheric aircraft with a ramjet nuclear engine

Designers in the USA and USSR considered “breathing” nuclear installations capable of drawing in outside air and heating it to colossal temperatures. Probably, this principle of thrust generation was borrowed from ramjet engines, only instead of rocket fuel, the fission energy of atomic nuclei of uranium dioxide 235 was used.

In the USA, such an engine was developed as part of the Pluto project. The Americans managed to create two prototypes of the new engine - Tory-IIA and Tory-IIC, which even powered up the reactors. The installation capacity was supposed to be 600 megawatts.

The engines developed as part of the Pluto project were planned to be installed on cruise missiles, which in the 1950s were created under the designation SLAM (Supersonic Low Altitude Missile, supersonic low-altitude missile).

The United States planned to build a rocket 26.8 meters long, three meters in diameter, and weighing 28 tons. The rocket body was supposed to contain a nuclear warhead, as well as a nuclear propulsion system having a length of 1.6 meters and a diameter of 1.5 meters. Compared to other sizes, the installation looked very compact, which explains its direct-flow principle of operation.

The developers believed that, thanks to the nuclear engine, the SLAM missile's flight range would be at least 182 thousand kilometers.

In 1964, the US Department of Defense closed the project. Official reason The reason was that in flight a cruise missile with a nuclear engine pollutes everything around too much. But in fact, the reason was the significant costs of maintaining such rockets, especially since by that time rocketry was rapidly developing based on liquid-propellant rocket engines, the maintenance of which was much cheaper.

The USSR remained faithful to the idea of ​​​​creating a ramjet design for nuclear engines much longer than the United States, closing the project only in 1985. But the results turned out to be much more significant. Thus, the first and only Soviet nuclear rocket engine was developed at the Khimavtomatika design bureau, Voronezh. This is RD-0410 (GRAU Index - 11B91, also known as “Irbit” and “IR-100”).

RD-0410 used a heterogeneous thermal neutron reactor, the moderator was zirconium hydride, the neutron reflectors were made of beryllium, the nuclear fuel was a material based on uranium and tungsten carbides, with about 80% enrichment in the 235 isotope.

The design included 37 fuel assemblies, covered with thermal insulation that separated them from the moderator. The design provided that the hydrogen flow first passed through the reflector and moderator, maintaining their temperature at room temperature, and then entered the core, where it cooled the fuel assemblies, heating up to 3100 K. At the stand, the reflector and moderator were cooled by a separate hydrogen flow.

The reactor went through a significant series of tests, but was never tested for its full operating duration. However, the outside reactor components were completely exhausted.

Technical characteristics of RD 0410

Thrust in void: 3.59 tf (35.2 kN)
Reactor thermal power: 196 MW
Specific thrust impulse in vacuum: 910 kgf s/kg (8927 m/s)
Number of starts: 10
Working resource: 1 hour
Fuel components: working fluid - liquid hydrogen, excipient- heptane
Weight with radiation protection: 2 tons
Engine dimensions: height 3.5 m, diameter 1.6 m.

Relatively small overall dimensions and weight, high temperature of nuclear fuel (3100 K) with an effective cooling system with a hydrogen flow indicate that the RD0410 is an almost ideal prototype of a nuclear propulsion engine for modern cruise missiles. And, considering modern technologies obtaining self-stopping nuclear fuel, increasing the resource from an hour to several hours is a very real task.

Nuclear rocket engine designs

Nuclear rocket engine (NRE) - jet engine, in which the energy generated by a nuclear fission or fusion reaction heats the working fluid (most often hydrogen or ammonia).

There are three types of nuclear propulsion engines depending on the type of fuel for the reactor:

• solid phase;
• liquid phase;
• gas phase.

The most complete is the solid-phase version of the engine. The figure shows a diagram of the simplest nuclear powered engine with a solid nuclear fuel reactor. The working fluid is located in an external tank. Using a pump, it is supplied to the engine chamber. In the chamber, the working fluid is sprayed using nozzles and comes into contact with the fuel-generating nuclear fuel. When heated, it expands and flies out of the chamber through the nozzle at great speed.

In gas-phase nuclear propellant engines, the fuel (for example, uranium) and the working fluid are in a gaseous state (in the form of plasma) and are held in the working area by an electromagnetic field. Uranium plasma heated to tens of thousands of degrees transfers heat to the working fluid (for example, hydrogen), which, in turn, being heated to high temperatures forms a jet stream.

Based on the type of nuclear reaction, a distinction is made between a radioisotope rocket engine, a thermonuclear rocket engine and a nuclear engine itself (the energy of nuclear fission is used).

An interesting option is also a pulsed nuclear rocket engine - it is proposed to use a nuclear charge as a source of energy (fuel). Such installations can be of internal and external types.

The main advantages of nuclear powered engines are:

• high specific impulse;
• significant energy reserves;
• compactness of the propulsion system;
• the possibility of obtaining very high thrust - tens, hundreds and thousands of tons in a vacuum.

The main disadvantage is the high radiation hazard of the propulsion system:

• fluxes of penetrating radiation (gamma radiation, neutrons) during nuclear reactions;
• removal of highly radioactive compounds of uranium and its alloys;
• outflow of radioactive gases with the working fluid.

Nuclear propulsion system

Considering that it is impossible to obtain any reliable information about nuclear power plants from publications, including from scientific articles, the operating principle of such installations is best considered using examples of open patent materials, although they contain know-how.

For example, the outstanding Russian scientist Anatoly Sazonovich Koroteev, the author of the invention under the patent, provided a technical solution for the composition of equipment for a modern YARD. Below I present part of the said patent document verbatim and without comment.

The essence of the proposed technical solution is illustrated by the diagram presented in the drawing. A nuclear propulsion system operating in a propulsion-energy mode contains an electric propulsion system (EPS) (the example diagram shows two electric rocket engines 1 and 2 with corresponding feed systems 3 and 4), a reactor installation 5, a turbine 6, a compressor 7, a generator 8, heat exchanger-recuperator 9, Ranck-Hilsch vortex tube 10, refrigerator-radiator 11. In this case, turbine 6, compressor 7 and generator 8 are combined into a single unit - a turbogenerator-compressor. The nuclear propulsion unit is equipped with working fluid pipelines 12 and electrical lines 13 connecting the generator 8 and the electric propulsion unit. The heat exchanger-recuperator 9 has the so-called high-temperature 14 and low-temperature 15 working fluid inputs, as well as high-temperature 16 and low-temperature 17 working fluid outputs.

The output of the reactor unit 5 is connected to the input of turbine 6, the output of turbine 6 is connected to the high-temperature input 14 of the heat exchanger-recuperator 9. The low-temperature output 15 of the heat exchanger-recuperator 9 is connected to the entrance to the Ranck-Hilsch vortex tube 10. The Ranck-Hilsch vortex tube 10 has two outputs , one of which (via the “hot” working fluid) is connected to the radiator refrigerator 11, and the other (via the “cold” working fluid) is connected to the input of the compressor 7. The output of the radiator refrigerator 11 is also connected to the input to the compressor 7. Compressor output 7 is connected to the low-temperature 15 input to the heat exchanger-recuperator 9. The high-temperature output 16 of the heat exchanger-recuperator 9 is connected to the input to the reactor installation 5. Thus, the main elements of the nuclear power plant are interconnected by a single circuit of the working fluid.

The nuclear power plant works as follows. The working fluid heated in the reactor installation 5 is sent to the turbine 6, which ensures the operation of the compressor 7 and the generator 8 of the turbogenerator-compressor. Generator 8 generates electrical energy, which is sent through electrical lines 13 to electric rocket engines 1 and 2 and their supply systems 3 and 4, ensuring their operation. After leaving the turbine 6, the working fluid is sent through the high-temperature inlet 14 to the heat exchanger-recuperator 9, where the working fluid is partially cooled.

Then, from the low-temperature outlet 17 of the heat exchanger-recuperator 9, the working fluid is directed into the Ranque-Hilsch vortex tube 10, inside which the working fluid flow is divided into “hot” and “cold” components. The “hot” part of the working fluid then goes to the refrigerator-emitter 11, where this part of the working fluid is effectively cooled. The “cold” part of the working fluid goes to the inlet of the compressor 7, and after cooling, the part of the working fluid leaving the radiating refrigerator 11 also follows there.

Compressor 7 supplies the cooled working fluid to the heat exchanger-recuperator 9 through the low-temperature inlet 15. This cooled working fluid in the heat exchanger-recuperator 9 provides partial cooling of the counter flow of the working fluid entering the heat exchanger-recuperator 9 from the turbine 6 through the high-temperature inlet 14. Next, the partially heated working fluid (due to heat exchange with the counter flow of the working fluid from the turbine 6) from the heat exchanger-recuperator 9 through the high-temperature outlet 16 again enters the reactor installation 5, the cycle is repeated again.

Thus, a single working fluid located in a closed loop ensures continuous operation of the nuclear power plant, and the use of a Ranque-Hilsch vortex tube as part of the nuclear power plant in accordance with the claimed technical solution improves the weight and size characteristics of the nuclear power plant, increases the reliability of its operation, simplifies its design and makes it possible to increase efficiency of nuclear power plants in general.

Links: Nuclear engines

At the end of the 40s, in the wake of euphoria from the prospects of using nuclear energy, both the USA and the USSR began work on installing nuclear engines on everything that could move. The idea of ​​creating such a “perpetual” engine was especially attractive for the military. Nuclear power plants (NPPs) have primarily found application in navy since ship power plants were not subject to such strict size and weight requirements as, for example, in aviation. Nevertheless, the Air Force could not “pass by” the opportunity to unlimitedly increase the range of strategic aviation. In May 1946 The US Air Force command approved the project to create nuclear engines to equip strategic bombers “Nuclear Energy for the Propulsion of Aircraft” (abbreviated as NEPA, translated as “Nuclear Energy for Aircraft Engines”). Work on its implementation began at the Oak Ridge National Laboratory. In 1951 it was replaced by a joint program of the Air Force and the Atomic Energy Commission (AEC) “Aircraft Nuclear Propulsion” (ANP, “Aviation Nuclear Propulsion”). The General Electric company created a turbojet (TRJ), which differed from the “ordinary” one only in that instead of a conventional combustion chamber there was a nuclear reactor that heated the air compressed by the compressor. At the same time, the air became radioactive - an open circuit. In those years, they treated this more simply, but still, in order not to pollute their airfield, the aircraft for takeoff and landing were supposed to be equipped with conventional kerosene engines. The first US nuclear aircraft project was created on the basis of the B-58 supersonic strategic bomber. The developer (Convair) designated it X-6. Four nuclear-powered turbojet engines were placed under the delta wing; in addition, 2 more “regular” turbojet engines were supposed to operate during takeoff and landing. By the mid-1950s, a prototype of a small air-cooled nuclear reactor with a power of 1 MW was manufactured. A B-36H bomber was allocated for its flight and crew protection tests. The crew of the flying laboratory was in a protective capsule, but the reactor itself, located in the bomb bay, did not have biological protection. The flying laboratory was named NB-36H. Since July 1955 to March 1957 she made 47 flights over the desert regions of Texas and New Mexico, during which the reactor was turned on and off. At the next stage, a new HTRE nuclear reactor was created (its last model had a power of 35 MW, sufficient to operate two engines) and the experimental X-39 engine, which successfully passed joint ground-based bench tests. However, by this time the Americans realized that the open circuit was not suitable, and began designing a power plant with air heating in a heat exchanger. The new Convair NX-2 had a canard design (the horizontal tail was located in front of the wing). The nuclear reactor was to be located in the center section, the engines in the rear, and the air intakes under the wing. The aircraft was supposed to use from 2 to 6 auxiliary turbojet engines. But in March 1961 the ANP program was closed. In 1954-1955. a group of scientists at the Los Alamos Laboratory prepared a report on the possibility of creating a nuclear rocket engine (NRE). The US AEC decided to begin work on its creation. The program was called "Rover". Work was carried out in parallel at the Los Alamos Scientific Laboratory and at the Livermore Radiation Laboratory at the University of California. Since 1956, all the efforts of the Radiation Laboratory have been aimed at creating a nuclear ramjet engine (NRJE) according to the PLUTO project (in Los Alamos they began to create a NJRE).

The nuclear-powered jet engine was planned to be installed on a supersonic low-altitude missile (SLAM) that was being developed. The missile (now it would be called a cruise missile) was essentially an unmanned bomber with a vertical launch (using four solid-fuel boosters). The nuclear-powered jet engine was turned on when a certain speed was reached and already at a sufficient distance from its own territory. The air entering through the air intake was heated in the nuclear reactor and, flowing through the nozzle, created thrust. The flight to the target and the release of warheads for stealth purposes had to be carried out at ultra-low altitude at a speed three times the speed of sound. The nuclear reactor had a thermal power of 500 MW, the operating temperature of the core was more than 1600 degrees C. A special testing ground was built to test the engine.

Since the stand was stationary, 500 tons were pumped into special tanks to ensure the operation of the nuclear-propelled jet engine. compressed air (requiring a ton of air per second to operate at full power). Before being supplied to the engine, the air was heated to a temperature of more than 700 degrees. passing it through four tanks filled with 14 million hot steel balls. May 14, 1961 The prototype nuclear-powered jet engine, named Tory-IIA, turned on. He worked for only a few seconds and developed only part of the
Soviet Union a nuclear aircraft was much more necessary than the United States because it did not have military bases near the US borders and could only operate from its own territory, and the M-4 and Tu-95 strategic bombers that appeared in the mid-50s could not “cover” the entire territory of the United States . Work on studying the problems of creating nuclear power plants for ships, submarines and aircraft began already in 1947. However, the resolution of the Council of Ministers on the start of work on nuclear-powered aircraft was issued only on August 12, 1955. (by this time the first Soviet nuclear submarine was already being built). Tupolev's OKB-156 and Myasishchev's OKB-23 began designing aircraft with nuclear power plants, and Kuznetsov's OKB-276 and Lyulka's OKB-165 were developing such power plants themselves. In March 1956 A government decree was issued on the creation (to study the influence of radiation on the design of an aircraft and its equipment, as well as radiation safety issues) of a flying laboratory based on the Tu-95 strategic bomber. In 1958 An experimental, “aircraft” nuclear reactor was delivered to the Semipalatinsk test site. In mid-1959 The reactor was installed on a production aircraft designated Tu-95LAL (Flying Atomic Laboratory). The reactor is used
was called only as a source of radiation and was cooled with water. The radiator of the cooling system, located at the bottom of the fuselage, was blown by the incoming air flow. In May-August 1961 Tu-95LAL made 34 flights over the test site. The next step was to create an experimental Tu-119 based on the Tu-95. On two (of
Its four NK-12M engines (Kuznetsov OKB) in addition to the combustion chambers were equipped with heat exchangers heated by a liquid metal coolant that took heat from a nuclear reactor located in the cargo compartment. The engines were designated NK-14A. In the future, it was planned to install 4 NK-14A engines on the aircraft and increase the diameter of the fuselage, to create an anti-submarine aircraft with an almost unlimited flight duration. However, the design of the NK-14A engines, or rather its nuclear part, proceeded slowly due to the many problems that arose during this process. As a result, plans to create the Tu-119 were never realized. In addition, OKB-156 offered several options for supersonic bombers. Long-range bomber Tu-120 with a take-off weight of 85 tons. 30.7 m long. wingspan 24.4 m. And
maximum speed of about 1400 km/h. Another project was a low-altitude attack aircraft with a take-off weight of 102 tons. 37m long. wingspan 19m. and a maximum speed of 1400 km/h. The plane had a low-lying delta wing. Its two engines were located in one package at the rear of the fuselage. During takeoff and landing, the engines ran on kerosene. The supersonic strategic bomber was supposed to have a take-off weight of 153 tons. length 40.5 m. and wingspan 30.6 m. Of the six turbojet engines (Kuznetsov Design Bureau), two, located in the tail, were equipped with heat exchangers and could be powered by a nuclear reactor. Four conventional turbojet engines were placed under the wing on pylons. Externally, this aircraft was similar to the American B-58 medium supersonic bomber. The Myasishchev Design Bureau also considered the possibility of creating a “nuclear” aircraft based on the existing ZM bomber by replacing conventional turbojet engines with nuclear ones equipped with heat exchangers (the reactor was located in the bomb bay). The possibility of creating a supersonic bomber M-60 was also considered. Several options were proposed
Arrangement options with different types of engines (take-off weight 225-250t, payload - 25t, speed - up to 3000 km/h, length 51-59m, wingspan - 27-31m). To protect against radiation, the pilots were placed in a special sealed capsule and the engines were placed in the rear fuselage. Visual visibility from the capsule was excluded and the autopilot had to guide the plane to the target. To ensure manual control, it was planned to use television and radar screens. The developers initially proposed making the plane unmanned. But for the sake of reliability, the military insisted on a manned version. One option was a seaplane. Its advantage was that the damped reactors could be lowered into water to reduce background radiation. With the development of rocketry and the advent of reliable intercontinental ballistic missiles and nuclear missile submarines, military interest in nuclear bombers faded and work was curtailed. But in 1965 The idea of ​​creating a nuclear anti-submarine aircraft was returned to again. This time the prototype was the heavy transport An-22 “Antey”, which had the same engines as the Tu-95. The development of the NK-14A was quite advanced by that time. Take-off and landing were to be carried out on kerosene (engine power 4 x 13000 hp), and cruising flight - on nuclear energy (4 x 8900 hp). The flight duration was limited only by the “human factor”; to limit the dose received by the crew, it was set to 50 hours. The flight range would be 27,500 km. In 1972 The An-22 with a nuclear reactor on board made 23 flights; first of all, radiation protection was checked. However, environmental problems in the event of an airplane accident were never resolved, perhaps this was the reason that the project was not implemented. In the 80s, interest arose in the nuclear aircraft as a carrier of ballistic missiles. Being almost constantly in the air, it would be invulnerable to a sudden enemy nuclear missile strike. In the event of an airplane accident, the nuclear reactor could be separated and lowered by parachute. But the beginning of detente, “perestroika” and then the collapse of the USSR did not allow the nuclear plane to take off. In the mid-50s, OKB-301 (chief designer S.A. Lavochkin) worked on the issue of installing a ramjet nuclear engine on the Burya intercontinental cruise missile (similar to the PLUTO project). The project received the designation "375". The development of the rocket itself was not a problem; the engine engineers failed. OKB-670 (chief designer M.M. Bondaryuk) for a long time could not cope with the creation of a ramjet nuclear engine. In 1960 The Tempest project was closed along with its nuclear version. It never got to the point of testing a nuclear engine. Nuclear energy can be used to heat the working fluid not only in an air-breathing engine, but also in a nuclear rocket engine (NRE), which are usually divided into reactive ones, in which the process of heating the working fluid (RT) occurs continuously, and pulsed or pulsating (also in generally reactive), in which nuclear energy is released discretely, through a series of low-power nuclear (thermonuclear) explosions. Based on the state of aggregation of nuclear fuel in the reactor core, nuclear propulsion engines are divided into solid-phase, liquid-phase and gas-phase (plasma). Separately, we can distinguish a nuclear-powered engine in a reactor in which the nuclear fuel is in a fluidized state (in the form of a rotating “cloud” of dust particles). Another type of nuclear propulsion engine is an engine that uses thermal energy released during the spontaneous fission of radioactive isotopes ( radioactive decay ). The advantage of such an engine is its simplicity of design; a significant disadvantage is the high cost of isotopes (for example, polonium-210). In addition, during the spontaneous decay of an isotope, heat is constantly released, even when the engine is turned off, and it must be somehow removed from the engine, which complicates and makes the design heavier. In a pulsed nuclear rocket engine, the energy of an atomic explosion evaporates the RT, turning it into plasma. The expanding plasma cloud puts pressure on the powerful metal bottom (pusher plate) and creates jet thrust. A solid substance that can be easily converted into gas, applied to a pusher plate, liquid hydrogen or water stored in a special tank can be used as RT. This is a scheme of the so-called pulsed external-action NPP; another type is the internal-action pulsed NPP, in which the detonation of small nuclear or thermonuclear charges is carried out inside special chambers (combustion chambers) equipped with jet nozzles. RT is also supplied there, which, flowing through the nozzle, creates thrust like conventional liquid-propellant rocket engines. Such a system is more efficient, since all the RT and explosion products are used to create thrust. However, the fact that explosions occur inside a certain volume imposes restrictions on the pressure and temperature in the combustion chamber. A pulsed external-action NRE is simpler, and the huge amount of energy released in nuclear reactions makes it possible to obtain good characteristics of such systems even with a lower efficiency. In the USA in 1958–63. A project for a rocket with a pulsed nuclear propulsion engine "Orion" was being developed. A model of an aircraft with a pulse engine was even tested using conventional chemical explosives. The results obtained indicated the fundamental possibility of controlled flight of the vehicle using such an engine. Initially, Orion was supposed to be launched from Earth. To exclude the possibility of damage to the rocket from a ground-based nuclear explosion, it was planned to install it on eight 75-meter towers for launch. At the same time, the launch mass of the rocket reached 10,000 tons. and the diameter of the pushing plate is about 40m. To reduce dynamic loads on the rocket structure and crew, a damping device was provided. After a compression cycle, it returned the plate to its initial position, after which another explosion occurred. At launch, a charge with a power of 0.1 kt was detonated every second. After leaving the atmosphere, charges with a power of 20 kt. exploded every 10 seconds. Later, in order not to pollute the atmosphere, it was decided to lift Orion from the Earth using the first stage of the Saturn-5 rocket, since its maximum diameter was 10 m. then the diameter of the pushing plate was cut to
10 m. The effective thrust accordingly decreased to 350 tons with its own “dry” weight of the propulsion unit (without RT) of 90.8 tons. To deliver a payload of 680 tons to the lunar surface. it would be necessary to explode about 800 plutonium charges (plutonium mass 525 kg) and consume about 800 tons. RT. The option of using Orion as a means of delivering nuclear charges to a target was also considered. But the military soon abandoned this idea. And in 1963 An agreement was signed banning nuclear explosions in outer space on earth (in the atmosphere) and under water. This outlawed the entire project. A similar project was considered in the USSR, but it did not have any practical results. Just like the Myasishchev Design Bureau’s M-19 aerospace aircraft (VKS) project. The project envisaged the creation of a reusable, single-stage aerospace system capable of launching a payload weighing up to 40 tons into low reference orbits (up to 185 km). For this purpose, the VKS was supposed to be equipped with a nuclear propulsion engine and a multi-mode air-breathing propulsion system operating both from a nuclear reactor and on hydrogen fuel. More details about this project are described on the page. Nuclear energy can not only be directly used to heat the RT in the engine, but also be converted into electrical energy, which is then used to create thrust in electric propulsion engines (EPEs). According to this scheme, nuclear power propulsion systems (NPS) are built, consisting of nuclear power plants (NPS) and electric rocket propulsion systems (ERPS). There is no established (generally accepted) classification of electric propulsion. According to the predominant “mechanism” of RT acceleration, electric propulsion engines can be divided into gas-dynamic (electrochemical), electrostatic (ionic) and electromagnetic (plasma). In electrochemical, electrical energy is used to heat or chemical decomposition RT (electric heating, thermocatalytic and hybrid) in this case the RT temperature can reach 5000 degrees. Acceleration of the RT occurs, as in conventional liquid-propellant rocket engines, when it passes through the gas-dynamic path of the engine (nozzle). Electrochemical engines consume the least power per unit of thrust among electric propulsion engines (about 10 kW/kg). In an electrostatic electric propulsion engine, the working fluid is first ionized, after which positive ions are accelerated in an electrostatic field (using a system of electrodes) creating thrust (to neutralize the charge of the jet stream, electrons are injected into it at the exit from the engine). In an electromagnetic electric propulsion engine, the RT is heated to the state of plasma (tens of thousands of degrees) by an electric current passing through it. Then the plasma is accelerated in an electromagnetic field (“gas-dynamic acceleration can also be applied in parallel”). Low molecular weight or easily dissociating gases and liquids are used as RT in electrothermal electric propulsion engines; in electrostatic ones, alkaline or heavy, easily evaporating metals or organic liquids; in electromagnetic ones, various gases and solids are used. An important parameter of the engine is its specific thrust impulse (see page) characterizing its efficiency (the larger it is, the less PT is spent on creating a kilogram of thrust). Specific impulse for different types engines varies over a wide range: solid propellant thruster - 2650 m/s, liquid propellant rocket engine - 4500 m/s, electrochemical thruster - 3000 m/s, plasma thruster up to 290 thousand. As is known, the specific impulse value is directly proportional to the square root of the RT temperature in front of the nozzle. It (temperature) in turn is determined by the calorific value of the fuel. The best indicator among chemical fuels is beryllium + oxygen pair - 7200 kcal/kg. Calorific value Uranium-235 is approximately 2 million times higher. However, the amount of energy that can be usefully used is only 1400 times greater. Limitations imposed by design features reduce this figure for a solid-phase nuclear propulsion engine to 2-3 (the maximum achievable RT temperature is about 3000 degrees). And yet, the specific impulse of a solid-phase nuclear-propellant rocket engine is approximately 9000 m/s, versus 3500-4500 for modern liquid-propellant rocket engines. For liquid-phase nuclear engines, the specific impulse can reach 20,000 m/sec; for gas-phase ones, where the RT temperature can reach tens of thousands of degrees, the specific impulse is 15-70 thousand m/sec. Another important parameter characterizing the weight perfection of a propulsion unit (PS) or engine is their specific gravity - the ratio of the weight of the PS (with or without fuel components) or the engine to the generated thrust. Its inverse quantity, specific thrust, is also used. Specific gravity (thrust) determines the achievable acceleration of the aircraft and its thrust-to-weight ratio. Modern liquid-propellant rocket engines have a specific gravity of 7-20 kg. thrust per ton of dead weight i.e. the thrust-to-weight ratio reaches 14. NREs also have a good thrust-to-weight ratio - up to 10. Moreover, for liquid-propellant rocket engines using oxygen-hydrogen fuel, the ratio of the RT mass to the mass of the structure is in the range of 7-8. For solid-phase nuclear propulsion engines, this parameter is reduced to 3-5, which provides a gain in the specific gravity of the propulsion system taking into account the weight of the RT. In an electric propulsion engine, the thrust developed is limited by the large energy consumption to create 1 kg. thrust (from 10 kW to 1 MW). The maximum thrust of existing electric propulsion engines is several kilograms. If the electric propulsion system contains additional elements related to the electric propulsion supply, the thrust-to-weight ratio of a vehicle with such a propulsion system is much less than one. This makes it impossible to use them to launch payloads to low-Earth orbit (some electric propulsion engines can generally only operate in the vacuum of space). It makes sense to use electric propulsion engines only in spacecraft as low-thrust engines for orientation, stabilization and correction of orbits. Due to the low flow rate of the working fluid (high specific impulse), the continuous operation time of the electric propulsion engine can be measured in months and years. Providing electric propulsion engines with electricity from a nuclear reactor will make it possible to use them for flights to the “outskirts” of the Solar system, where the power of solar batteries will not be enough. Thus, the main advantage of nuclear engines over other types of rocket engines is their large specific impulse, with a high thrust-to-weight ratio (tens, hundreds and thousands of tons of thrust with a significantly lower dead weight). The main disadvantage of the NRE is the presence of a powerful flow of penetrating radiation as well as the removal of highly radioactive uranium compounds from the spent RT. In this regard, the nuclear powered rocket engine is unacceptable for ground launches. Work on the creation of nuclear propulsion engines and nuclear power plants in the USSR began in the mid-50s. In 1958 The Council of Ministers of the USSR adopted a number of resolutions on carrying out research work on the creation of rockets with nuclear propulsion engines. Scientific supervision was entrusted to M.V. Keldysh, I.V. Kurchatov and S.P. Korolev. Dozens of research, design, construction and installation organizations were involved in the work. These are NII-1 (now the Keldysh Research Center), OKB-670 (chief designer M.M. Bondaryuk), the Institute of Atomic Energy (IAE, now the Kurchatov Institute) and the Physics and Energy Institute (now the IPPE Leypunsky), Research Institute of Instrument Engineering (chief designer A.S. Abramov), NII-8 (now Scientific Research and Design Institute - NIKIET named after Dolezhal) and OKB-456 (now NPO Energomash named after Glushko), NIITVEL (NPO "Luch", now the Podolsk Scientific Research Technological Institute - PNITI), NII-9 (now the High-Technological Research Institute of Inorganic Materials - VNIINM named after A.A. Bochvar), etc. In OKB-1 (in Subsequently, the name was changed to the Central Design Bureau of Experimental Mechanical Engineering - TsKBEM, NPO Energia, RSC Energia named after Korolev) preliminary designs of a single-stage ballistic missile YAR-1 and a two-stage nuclear chemical rocket YAHR-2 were developed. Both provided for the use of nuclear propulsion engines with a thrust of 140 tons. The projects were ready by December 30, 1959. however, the creation of a combat YAR-1 was considered inappropriate and work on it was stopped. The YakhR-2 had a design similar to the R-7, but with six first-stage side rocket pods equipped with NK-9 engines. The second stage (central block) was equipped with a nuclear propulsion engine. The launch mass of the rocket was 850-880 tons. with a payload mass of 35-40t. (an option with a launch weight of 2000 tons, a length of 42 m, a maximum transverse dimension of 19 m, a payload of up to 150 tons was also considered). The engines of all YakhR-2 units were started on Earth. In this case, the nuclear propulsion engine was put into “idle” mode (the reactor power was 0.1% of the nominal one with no flow of working fluid). The switch to operating mode was carried out in flight a few seconds before the separation of the side blocks. In mid-1959 OKB-1 issued technical specifications to engine engineers (OKB-670 and OKB-456) for the development of preliminary designs of nuclear powered engines with a thrust of 200 and 40 tons. After the start of work on the N-1 heavy launch vehicle, the issue of creating a two-stage launch vehicle with a nuclear propulsion engine in the second stage was considered on its basis. This would ensure an increase in the payload launched into low-Earth orbit by no less than 2-2.5 times, and the lunar satellite orbit by 75-90%. But this project was not completed either - the N-1 rocket never flew. The design of the nuclear powered engines was carried out by OKB-456 and OKB-670. They completed several preliminary designs of nuclear propulsion engines with a solid-phase reactor. So in OKB-456 by 1959. The preliminary designs of the RD-401 engines with a water moderator and the RD-402 with a beryllium moderator, which had a vacuum thrust of 170 tons, were ready. with a specific thrust impulse of 428 sec. Liquid ammonia served as the working fluid. By 1962 According to the technical specifications of OKB-1, the RD-404 project with a thrust of 203 tons was completed. with a specific thrust impulse of 950 sec. (RT - liquid hydrogen), and in 1963. - RD-405 with a thrust of 40-50t. However, in 1963 all efforts of OKB-456 were redirected to the development of gas-phase nuclear propulsion engines. Several NRE projects with a solid-phase reactor and an ammonia-alcohol mixture as RT were developed by OKB-670 in the same years. To move from preliminary design to the creation of real samples of nuclear propulsion engines, it was necessary to solve many more issues and, first of all, to study the performance of fuel elements (fuel elements) of a nuclear reactor at high temperatures. Kurchatov in 1958 proposed to create for this purpose an explosive reactor (RVD, the modern name is a pulsed graphite reactor - IGR). Its design and production was entrusted to NII-8. In the RVD, the thermal energy of uranium fission was not removed outside the core, but heated the graphite from which (together with uranium) it was formed to very high temperatures. It is clear that such a reactor could only operate for a short time - in pulses, with stops to cool down. The absence of any metal parts in the core made it possible to produce “flares” whose power was limited only by the sublimation temperature of graphite. In the center of the active zone there was a cavity in which the test samples were located. Also in 1958. At the Semipalatinsk test site, not far from the testing site of the first atomic bomb, construction of the necessary buildings and structures began. In May-June 1960 A physical (“cold”) start-up of the reactor was carried out, and a year later a series of starts were carried out with heating of the graphite stack to 1000 degrees. To ensure environmental safety, the stand was built according to a “closed” scheme - the waste coolant was kept in gas tanks before being released into the atmosphere, and then filtered. Since 1962 At the IGR (RVD), tests of fuel rods and fuel assemblies (FA) of various types were carried out for nuclear-powered reactors developed at NII-9 and NII-1. In the second half of the 50s, NII-1 and IPPE carried out studies of the gas dynamics of gas fuel rods and the physics of gas-phase reactors, which showed the fundamental possibility of creating gas-phase nuclear propulsion engines. In the working chamber of such an engine, with the help of the magnetic field created by the solenoid surrounding it, a “stagnant” zone was created in which the uranium was heated to temperatures of about 9000 degrees. and heated the hydrogen flowing through this zone (to improve the absorption of radiant energy, special additives were added to it). Some of the nuclear fuel was inevitably carried away by the gas flow, so it was necessary to constantly compensate for the loss of uranium. A gas-phase nuclear propulsion engine could have a specific impulse of up to 20,000 m/sec. Work on such an engine began in 1963. at OKB-456 (under the scientific leadership of NII-1). In 1962 At IPPE, an experimental stand IR-20 was created with a solid-phase reactor in which water was the moderator. It was used for the first time to study the physical parameters of solid-phase NRE reactors, which served as the basis for subsequent designs. In 1968 Taking into account the experience gained at the IR-20 stand, a physical stand “Strela” was also built here, on which a reactor was installed, which was a design quite close to the reactor of the flight prototype NRE. The next step towards the creation of a nuclear propulsion engine was the creation of a special experimental stand for testing a ground-based prototype of a nuclear propulsion reactor. In 1964 A government decree was issued on the construction of a bench complex for testing nuclear propulsion engines at the Semipalatinsk test site, which received the name “Baikal”. By February 1965 The technical specifications for the development of a reactor for the Baikal complex were prepared at the IAE (it received the index IVG-1, research high-temperature gas-cooled). NII-8 (under the scientific leadership of the IAE) is starting to design it. The development and production of fuel assemblies is entrusted to NIITVEL. In 1966 the development of the first Soviet solid-phase nuclear propulsion engine (received the index 11B91 or RD-0410) was transferred to the Voronezh Design Bureau of Khimavtomatiki (KBKhA) Ch. designer A.D. Konopatov. In 1968 NPO Energomash (OKB-456) completed the development of a preliminary design of an engine with a gas-phase reactor. The engine, designated RD-600, was supposed to have a thrust of about 600 tons. with its own weight of about 60 tons. Beryllium and graphite were used as a moderator and reflector. RT - hydrogen with lithium additive. May 24, 1968 A government decree was issued that provided for the creation of a nuclear propulsion engine based on the proposed project, as well as the construction of a bench base for its testing, called “Baikal-2”. In parallel with the development of the flight model of the YARD 11B91 at KBKhA, its bench prototype (IR-100) was created at NII-1. In 1970 These works were combined (the program received the index 11B91-IR-100) and all design work on bench and flight models of the nuclear propulsion system was concentrated in KBKhA. The physical launch of the first YARD 11B91-IR-100 reactor was carried out at the IPPE at the Strela stand. An extensive research program was carried out on it. Construction of the Baikal complex lasted several years. The complex was supposed to consist of two shafts where the experimental reactors were lowered using a gantry crane. September 18, 1972 The physical launch of the IVG-1 reactor took place as part of the first workplace of the Baikal complex. It could also be used as a bench prototype of a future nuclear-powered rocket engine with a thrust of 20–40 tons. and as a stand for testing new types of nuclear fuel. The reactor had a beryllium reflector and the moderator was water. Its core consisted of 31 fuel assemblies. Hydrogen, cooling nuclear fuel, could heat up to 2500 degrees, and in a special central channel it was possible to get all 3000. The power start-up took place only in early March 1975. which was explained by the need to complete the construction of all buildings and structures of the test bench complex, carry out a large volume of commissioning work and personnel training. There were instruments in an underground bunker located between the shafts. In another one located 800m away. there was a control panel. The control panel could be reached from the safe zone through a one and a half kilometer underground tunnel. Near the mine at a depth of 150m. A spherical container was placed into which hydrogen gas was pumped under high pressure. Heated into the reactor to almost 3000 degrees. hydrogen was released directly into the atmosphere. However, the removal of fission products was close to the radioactive emissions of nuclear power plants during their normal operation. And yet, approaching the mine closer than one and a half kilometers was not allowed for 24 hours, and it was forbidden to approach the mine itself for a month. Over 13 years of operation, 28 “hot” starts of the IVG-1 reactor were carried out. About 200 gas-cooled fuel assemblies were tested as part of 4 experimental cores. The service life of a number of assemblies at rated power was 4000 seconds. Many of the results of these tests significantly exceed those obtained during the work on the nuclear propulsion program in the United States, for example, the maximum heat release density in the core of the IVG-1 reactor reached 25 kW/cc. versus 5.2 for the Americans, the temperature of the hydrogen at the outlet of the fuel assemblies was about 2800 degrees versus 2300 for the Americans. In 1977 The second-A workplace of the Baikal bench complex was put into operation on September 17, 1977. The physical launch of the first bench reactor for the 11B91-IR-100 nuclear propulsion engine was carried out, which received the designation IRGIT. Six months later, March 27, 1978 power start-up was carried out. During which a power of 25 MW was achieved (15% of the design), the hydrogen temperature was 1500 degrees, the operating time was 70 seconds. During tests on July 3, 1978. and August 11, 1978 A power of 33 MW and 42 MW was achieved; the hydrogen temperature was 2360 degrees. In the late 70s and early 80s, two more series of tests were carried out at the bench complex - the second and third 11B91-IR-100 devices. Testing of fuel assemblies in the IGR and IVG reactors continued, and construction of structures was underway with the goal of commissioning a second-B workplace for testing the liquid hydrogen engine. At the same time, tests of the so-called “cold” 11B91X engine, which did not have a nuclear reactor, were carried out at a stand located in Zagorsk near Moscow. Hydrogen was heated in special heat exchangers from conventional oxygen-hydrogen burners. By 1977 All problems related to testing a “cold” engine were solved (the units could work for hours). In principle, the nuclear powered engine was created and preparing it for flight tests was a matter of several more years. The YARD 11B91 had a heterogeneous thermal neutron reactor, the moderator was zirconium hydride, the reflector was beryllium, a nuclear fuel material based on uranium and tungsten carbides, with a uranium-235 content of about 80%. It was a relatively small metal cylinder with a diameter of about 50 cm. and about a meter long. Inside are 900 thin rods containing uranium carbide. The NRE reactor was surrounded by a beryllium neutron reflector, into which drums were embedded, covered on one side with a neutron absorber. They played the role of control rods - depending on which side of the drums were facing the core, they absorbed more or less neutrons, regulating the power of the rector (the Americans had the same scheme). Around 1985 YARD 11B91 could make its first space flight. But this did not happen for many reasons. By the beginning of the 80s, significant progress had been made in the development of highly efficient liquid propellant engines, which, along with the abandonment of plans for the exploration of the Moon and other nearby planets of the Solar System, called into question the feasibility of creating nuclear propellant engines. The economic difficulties that arose and the so-called “Perestroika” led to the fact that the entire space industry found itself “in disgrace” and in 1988. work on nuclear propulsion in the USSR was stopped. The idea of ​​using electricity to create jet propulsion was expressed by K.E. Tsiolkovsky back in 1903. The first experimental electric propulsion engine was created at the Gas Dynamics Laboratory (Leningrad) under the leadership of V.P. Glushko in 1929-1933. The study of the possibility of creating electric propulsion engines began in the late 50s at the IAE (under the leadership of L.A. Artsimovich), NII-1 (under the leadership of V.M. Ievlev and A.A. Porotnikov) and a number of other organizations. nizations. Thus, OKB-1 conducted research aimed at creating a nuclear electric propulsion engine. In 1962 The preliminary design of the LV N1 included “Materials on nuclear power propulsion for heavy interplanetary spacecraft.” In 1960 A government decree was issued on the organization of work on electric propulsion. In addition to IAE and NII-1, dozens of other research institutes, design bureaus and organizations were involved in the work. By 1962 At NII-1, an erosion-type pulsed plasma engine (PPD) was created. In SPD, plasma is formed due to the evaporation (ablation) of a solid dielectric (fluoroplastic-4, also known as Teflon) in a pulsed (spark) electric discharge lasting several microseconds (pulse power 10-200 MW) followed by electromagnetic acceleration of the plasma. The first life tests of such an engine began on March 27 and continued until April 16, 1962. With an average power consumption of 1 kW (pulse - 200 MW), the thrust was 1 g. - “price” of traction 1 kW/g. For testing in space, the “price” of thrust was approximately 4 times lower. Such parameters were achieved by the end of 1962. The new engine consumed 50 W (pulse power 10 MW) to create a thrust of 0.2 g. (later the “price” of traction was increased to 85W per year). In March 1963 A remote control system for the spacecraft stabilization system based on IPD was created and tested, which included six motors, a voltage converter (the spark discharge was created by capacitors with a capacity of 100 μF with a voltage of 1 kV), a software switching device, high-voltage hermetic connectors and other equipment. The plasma temperature reached 30 thousand degrees. and the exhaust speed is 16 km/sec. The first launch of a spacecraft (an interplanetary station of the “Probe” type) with an electric propulsion engine was scheduled for November 1963. Launch November 11, 1963 ended in a launch vehicle accident. Only November 30, 1964 The Zond-2 probe with an electric propulsion system on board successfully launched towards Mars. December 14, 1964 At a distance of more than 5 million km from the Earth, plasma engines were turned on (gas-dynamic engines were turned off at this time) powered by solar batteries. Within 70min. six plasma engines maintained the necessary orientation of the station in space. In the USA in 1968 The communications satellite “LES-6” was launched with four erosion IPDs, which operated for more than 2 years. For further work on electric propulsion, the Fakel Design Bureau was organized (on the basis of the B.S. Stechkin Design Bureau in Kaliningrad). The first development of the Fakel Design Bureau was the electric propulsion system of the stabilization and orientation system for military-purpose spacecraft of the Globus type (the Horizon satellite), close to the Zond-2 IPD. Since 1971 the orbit correction system of the Meteor weather satellite used two plasma engine OKB "Fakel", each of which, weighing 32.5 kg, consumed about 0.4 kW, while developing a thrust of about 2 g. the exhaust velocity was over 8 km/sec and the amount of RT (compressed xenon) was 2.4 kg. Since 1982 Geostationary communication satellites “Luch” use electric propulsion systems developed by OKB “Fakel”. Until 1991 Electric propulsion engines operated successfully on 16 spacecraft. More details about electric propulsion will be discussed on a separate page of the website. The thrust of the created electric propulsion engines was limited by the electrical power of the onboard energy sources. To increase the thrust of the electric propulsion system to several kilograms, it was necessary to increase the power to several hundred kilowatts, which was practically impossible using traditional methods (batteries and solar panels). Therefore, in parallel with the work on electric propulsion, the IPPE, IAE and other organizations began work on the direct conversion of thermal energy of a nuclear reactor into electrical energy. The elimination of intermediate stages of energy conversion and the absence of moving parts made it possible to create compact, lightweight and reliable power plants of sufficiently high power and service life, suitable for use on spacecraft. In 1965 OKB-1, together with the IPPE, developed a preliminary design of the nuclear electric propulsion system YaERD-2200 for an interplanetary spacecraft with a crew. The propulsion system consisted of two blocks (each had its own nuclear power plant), the electrical power of each block was 2200 kW, thrust 8.3 kg. The magnetoplasma engine had a specific impulse of about 54,000 m/sec. In 1966-70. A preliminary design of a thermionic nuclear power plant (11B97) and electric propulsion system for the Martian complex launched by the N1M launch vehicle was developed. The nuclear electric propulsion system was assembled from separate blocks; the electrical power of one block was up to 5 MW. electric propulsion thrust - 9.5 kg. with a specific thrust impulse of 78000 m/sec. However, the creation of powerful nuclear sources electricity took much longer than expected. The first to find practical application, due to their simplicity of design and low weight, were radioisotope thermoelectric generators (RTGs) that used the heat of spontaneous fission of radioactive isotopes (for example, polonium-210). The thermoelectric converter was essentially an ordinary thermocouple. However, their relatively low energy intensity of RTGs and the high cost of the isotopes used greatly limited their use. The use of thermoelectric and thermionic energy converters in combination with nuclear reactors combined into a single unit (converter reactor) had the best prospects. To experimentally test the possibility of creating a small-sized reactor-converter, at the IEA (together with NPO Luch) in 1964. The experimental installation “Romashka” was created. The heat generated in the core heated a thermoelectric converter located on the outer surface of the reactor, consisting of a large number of silicon-germanium semiconductor wafers, while their other surface was cooled by a radiator. Electrical power was 500 W. at a reactor thermal power of 40 kW. Tests of "Romashka" were soon stopped because the BES-5 (Buk) nuclear power plant of much higher power was already being tested. The development of the BES-5 nuclear power plant with an electrical power of 2800 W, intended to power the equipment of the US-A radar reconnaissance spacecraft, began in 1961. at the NPO "Red Star" under the scientific leadership of the IPPE. The first flight of the US-A spacecraft (October 3, 1970, “Cosmos-367”) was unsuccessful - the BES-5 nuclear power plant operated for 110 minutes. after which the reactor core melted. The next 9 launches of the modified nuclear power plant were successful in 1975. The US-A spacecraft was adopted by the Navy. In January 1978 due to the failure of the US-A spacecraft (Cosmos -954), fragments of the Buk nuclear power plant fell on Canadian territory. In total (before decommissioning in 1989), 32 launches of these spacecraft were carried out. In parallel with the work on the creation of nuclear power plants with thermoelectric wire generators - work was carried out on nuclear power plants with thermionic converters that had higher efficiency, service life and weight-size characteristics. Thermionic nuclear power plants use the effect of thermionic emission from the surface of a sufficiently heated conductor. To test high-power thermionic converters, a reactor was created in 1964. base in Kyiv (in 1970 the same base appeared in Alma-Ata). The work was carried out by two developers - at NPO "Krasnaya Zvezda" (scientific management of the IPPE) the Topaz nuclear power plant was developed with an electrical power of 5-6.6 kW. for radar reconnaissance satellites, Energovak-TsKBM (scientific management of the RRC Kurchatov Institute) developed the Yenisei nuclear power plant for the Ekran-AM television broadcast satellite. The Topaz nuclear power plant was tested twice in space conditions on board the Plasma-A spacecraft (February 2, 1987, Cosmos-1818, and July 10, 1987, Cosmos-1867). With a design life of one year, already in the second flight “Topaz” worked for more than 11 months, but the launches stopped there. Work on the Yenisei nuclear power plant was stopped at the ground testing stage due to the cessation of work on the spacecraft for which it was intended. More details about Nuclear power sources for spacecraft will be discussed on a separate page of the site. In 1970 NPO Energomash developed a preliminary design of a space nuclear power plant with a gas-phase reactor (with a non-flowing zone of fissile material) EU-610 with an electrical power of 3.3 GW. However, problems that arose during the work did not allow this project to be implemented. In 1978 NPO Krasnaya Zvezda developed technical proposals for 2 variants of the Zarya-3 nuclear propulsion system with an electrical power of 24 kW and a service life of more than a year. The first option is a modification of the Topaz-1 nuclear power plant, the other had an original design (remote TECs with heat pipes). Work on the installations was stopped due to lack of connection to a specific spacecraft. In the period 1981-86. A large amount of design and experimental work was carried out, indicating the fundamental possibility of increasing the service life of nuclear power plants to 3-5 years and electrical power to 600 kW. In 1982 NPO Energia (TsKBEM), according to the terms of reference of the Moscow Region, developed a technical proposal for the Hercules nuclear interorbital tug with an electrical power of 550 kW, launched into a reference orbit at an altitude of 200 km. the Energia-Buran complex or the Proton launch vehicle. In 1986 a technical proposal was developed for the use of an inter-orbital tug with a nuclear electric propulsion system for transporting payloads weighing up to 100 tons into geostationary orbit, launched into the reference orbit of the Energia launch vehicle. But these works were not continued. Thus, the USSR never created a truly working nuclear propulsion system, although nuclear power plants were successfully operated on serial spacecraft. The first and only spacecraft to have a nuclear power plant with electric propulsion was the American “Snapshot”, launched on April 3, 1965. The electrical power of the converter reactor was 650 W. An experimental ion engine was installed on the device. However, the very first activation of the electric propulsion engine (on the 43rd day of the flight) led to an emergency shutdown of the reactor. Perhaps the reason for this was the high-voltage breakdowns that accompanied the operation of the electric propulsion engine, as a result of which a false command was sent to reset the reactor reflector, which led to its shutdown. In 1992 The United States purchased two Yenisei nuclear power plants from Russia. One of the reactors was supposed to be used in 1995. in “Space experiment with nuclear propulsion propulsion”. However, in 1996 the project was closed. In the USA, research on the problem of creating nuclear propulsion engines has been carried out at the Los Alamos Laboratory since 1952. In 1957 Work began on the Rover program. Unlike the USSR, where element-by-element testing of fuel assemblies and other engine elements was carried out, the USA took the path of creating and testing the entire reactor at once. The first reactor, named KIWI-A, was tested on July 1, 1959. at a special testing site in Nevada. It was a homogeneous reactor whose core was assembled from unprotected plates consisting of a mixture of graphite and uranium-235 oxide enriched to 90%. Heavy water served as a neutron moderator. Uranium oxide could not withstand high temperatures, and hydrogen passing through the channels between the plates could only heat up to 1600 degrees. The power of these reactors was only 100 MW. The Kiwi-A tests, like all subsequent ones, were carried out with an open ejection. The activity of the exhaust products was low and practically no restrictions were introduced on work in the test area. The reactor tests were completed on December 7, 1961. (during the last launch, the core was destroyed, and fragments of plates were released into the exhaust stream). The results obtained from six “hot tests” of nuclear-powered engines turned out to be very encouraging, and at the beginning of 1961. a report was prepared on the need to test the reactor in flight. However, soon the “dizziness” from the first successes began to pass, and the understanding came that there were many problems on the way to creating nuclear propulsion engines, the solution of which would require a lot of time and money. In addition, progress in the creation of chemical engines for combat missiles has left only the space sphere for the use of nuclear propulsion engines. Despite the fact that with the arrival of the Kennedy administration in the White House (in 1961), work on a nuclear-powered aircraft was stopped, the Rover program was called “one of the four priority areas in the conquest of space” and was further developed . New programs “Rift” (RIFT - Reactor In Flight Test) and “Nerva” (NERVA - Nuclear Engine for Rocket Vehicle Application) were adopted to create a flight version of the nuclear powered engine. Testing of the Kiwi series reactors continued. September 1, 1962 The Kiwi-V with a capacity of 1100 MW running on liquid hydrogen was tested. Uranium oxide was replaced with a more heat-resistant carbide, in addition, the rods began to be coated with niobium carbide, but during the test, when trying to reach the design temperature, the reactor began to collapse (pieces of plates began to fly out through the nozzle). The next launch took place on November 30, 1962. but after 260 sec. During operation, the test was stopped due to the appearance of strong vibration inside the reactor and flashes of flame in the exhaust stream. As a result of these failures, planned for 1963. tests of the Kiwi-V reactors were postponed until next year. In August 1964 Another test was carried out during which the engine operated at a power of 900 MW for more than eight minutes, developing a thrust of 22.7 tons. at an exhaust speed of 7500 m/sec. At the very beginning of 1965. the last test was carried out during which the reactor was destroyed. It was deliberately brought to the point of explosion as a result of rapid “acceleration”. If normally the transition of a reactor from zero power to full power requires tens of seconds, then in this test the duration of such a transition was determined only by the inertia of the control rods, and approximately 44 milliseconds after they were transferred to the full power position, an explosion equivalent to 50–60 kg occurred. trinitrotoluene. The Rift program involved the launch of a Saturn-V rocket with an experimental reactor along a ballistic trajectory to an altitude of up to 1000 km. and their subsequent fall into the southern Atlantic Ocean. Before entering the water, the nuclear reactor had to be blown up (few people thought about radiation safety at that time). But year after year the program was delayed and it was ultimately never implemented. At the first stage of work on the NERVA engine, it was based on a slightly modified Kiwi-V reactor, called NERVA-NRX (Nuclear Rocket Experimental - nuclear missile experimental). Since by this time a material capable of operating at 2700–3000 degrees had not yet been found. and to resist destruction by hot hydrogen, it was decided to reduce the operating temperature and the specific impulse was limited to 8400 m/sec. Tests of the reactor began in 1964, they achieved a power of 1000 MW and a thrust of approximately 22.5 tons. exhaust velocity is more than 7000m/s. In 1966 For the first time, the engine was tested at full power of 1100 MW. On which he worked for 28 minutes. (out of 110 minutes of work). The temperature of hydrogen at the outlet of the reactor reached 2000 degrees, the thrust was 20 tons. At the next stage of the program it was planned to use more powerful Phoebus reactors (Phoebus, and then Pewee). The development of improved solid-phase graphite reactors for the NERVA engine under the Phoebus program has been carried out at the Los Alamos Laboratory since 1963. The first of these reactors has approximately the same dimensions as the Kiwi-V (diameter 0.813 m, length 1.395 m), but is designed for approximately twice the power. On the basis of this reactor it was planned to create the NERVA-1 engine. The next modification with a power of about 4000–5000 MW was to be used for the NERVA-2 engine. This engine has a thrust in the range of 90-110t. should have had an exhaust velocity of up to 9000 m/s. Engine height is approximately 12m. outer diameter - 1.8 m. Working fluid consumption 136kg/s. The weight of the NERVA-2 engine was approximately 13.6 tons. Due to financial difficulties, the NERVA-2 engine was soon abandoned and switched to designing the NERVA-1 engine of increased power with a thrust of 34 tons. with an outflow speed of 8250 m/s. The first test of the NRX-A6 reactor for this engine was carried out on December 15, 1967. In June 1969 The first hot tests of the experimental NERVA XE engine at a thrust of 22.7 tons took place. The total engine operating time was 115 minutes, 28 starts were made. The NERVA-1 YARD had a homogeneous reactor with a core with a diameter of 1 m. and height 1.8 m. consisting of 1800 rod hexagonal fuel elements (concentration of nuclear fuel 200 - 700 mg/cc.). The reactor had a ring reflector about 150 mm thick, made of beryllium oxide. The reactor power vessel is made of aluminum alloy, the internal radiation shield is made of composite material (boron carbide–aluminum–titanium hydride). Additional external protection can also be installed between the reactor and the turbopump units. NASA considered the engine suitable for the planned flight to Mars. It was supposed to be installed on the upper stage of the Saturn 5 launch vehicle. Such a carrier could carry two or three times more payload into space than its purely chemical version. But much of the American space program was canceled by President Nixon's administration. And it stopped in 1970. The production of Saturn-5 rockets put a final end to the program for using nuclear propulsion engines. At Los Alamos, work on Pewee engines under the Rover program continued until 1972. after which the program was finally closed. The main difference between our nuclear-powered engines and the American ones is that they were heterogeneous. In homogeneous (homogeneous) reactors, nuclear fuel and moderator are mixed. In the domestic NRE, nuclear fuel was concentrated in fuel rods (separate from the moderator) and was enclosed in a protective shell, so that the moderator operated at much lower temperatures than in American reactors. This made it possible to abandon graphite and use zirconium hydride as a moderator. As a result, the reactor was much more compact and lighter than the graphite one. This, together with the shape of the rods found by Soviet designers (four-lobe in cross section and twisted along the length), made it possible to significantly reduce the loss of uranium as a result of the destruction of the rods (it was not possible to completely eliminate destruction). Currently only the US and Russia have significant experience development and construction of solid-phase nuclear propulsion engines, and, if necessary, will be able to create such engines in a short time and at an affordable price. The IGR and IVG-1 reactor complexes now belong to the National Nuclear Center of the Republic of Kazakhstan. The equipment is maintained in relatively working condition. It is possible that the resumption of work on flight programs to the Moon and Mars will revive interest in solid-phase nuclear propulsion engines. In addition, the use of nuclear propulsion engines can significantly expand the boundaries of the study of the Solar system, reducing the time required to reach distant planets. In 2010 Russian President Medvedev ordered the creation of a space transport and energy module based on nuclear power plants using ion electric propulsion systems. The creation of the reactor will be carried out by NIKIET. The Keldysh Center will create the nuclear propulsion system, and RSC Energia will create the transport and energy module itself. The output electrical power of the gas turbine converter at nominal mode will be 100-150 kW. It is proposed to use xenon as the RT. specific impulse of the electric propulsion engine 9000-50000m/sec. resource 1.5-3 years. The weight and dimensions of the installation must allow the use of Proton and Angara launch vehicles for its launch. Ground testing of a working prototype will begin in 2014, and by 2017 the nuclear engine will be ready for launch into space (NASA also began a similar program in 2003, but then funding was stopped). The development of the entire project will require 17 billion rubles. We'll wait and see.