Nuclear rocket engines. Nuclear rocket engine

Carefully many letters.

A flight prototype of a spacecraft with a nuclear power propulsion system (NPP) in Russia is planned to be created by 2025. The corresponding work is laid down in the draft of the Federal Space Program for 2016–2025 (FKP-25), sent by Roscosmos for approval to the ministries.

Nuclear power systems are considered the main promising sources of energy in space when planning large-scale interplanetary expeditions. Provision of megawatt power in space in the future will allow the nuclear power plant, the creation of which is now being carried out by the enterprises of Rosatom.

All work on the creation of a nuclear power plant is proceeding in accordance with the planned terms. We can say with a high degree of confidence that the work will be completed on time, stipulated by the target program, ”says Andrey Ivanov, project manager of the communications department of the Rosatom state corporation.

Per Lately within the framework of the project, two important stages have been passed: a unique design of the fuel element has been created, which ensures operability under the conditions high temperatures, large temperature gradients, high-dose irradiation. Technological tests of the reactor vessel of the future space power unit have also been successfully completed. As part of these tests, the body was subjected to overpressure and 3D measurements were carried out in the zones of the base metal, the annular welded joint and a conical transition.

Operating principle. History of creation.

WITH nuclear reactor there are no fundamental difficulties for space applications. In the period from 1962 to 1993, our country has accumulated rich experience in the production of similar installations. Similar work was carried out in the United States. Since the beginning of the 1960s, several types of electric jet engines have been developed in the world: ionic, stationary plasma, anode layer engine, pulsed plasma engine, magnetoplasma, magnetoplasmodynamic.

Work on the creation of nuclear engines for spacecraft was actively carried out in the USSR and the USA in the last century: the Americans closed the project in 1994, the USSR in 1988. The closure of the works was largely facilitated by the Chernobyl disaster, which negatively tuned public opinion towards the use of nuclear energy. In addition, tests of nuclear installations in space were not always carried out routinely: in 1978, the Soviet satellite "Kosmos-954" entered the atmosphere and collapsed, scattering thousands of radioactive fragments over an area of ​​100 thousand square meters. km in the northwestern regions of Canada. Soviet Union paid Canada more than $ 10 million in compensation.

In May 1988, two organizations - the Federation of American Scientists and the Committee of Soviet Scientists for Peace against the Nuclear Threat - made a joint proposal to ban the use of nuclear energy in outer space. That proposal did not receive formal implications, but since then no country has launched spacecraft with nuclear power plants on board.

The great advantages of the project are practically important operational characteristics - a long service life (10 years of operation), a significant overhaul interval and a long operating time with one switch-on.

In 2010, technical proposals for the project were formulated. From this year, the design began.

YaEDU contains three main devices: 1) reactor plant with a working fluid and auxiliary devices (heat exchanger-recuperator and turbo-generator-compressor); 2) an electric rocket propulsion system; 3) refrigerator-radiator.

Reactor.

From a physical point of view, it is a compact gas-cooled fast neutron reactor.
A compound (dioxide or carbonitride) of uranium is used as a fuel, but since the design must be very compact, uranium has a higher enrichment in isotope 235 than in fuel elements at conventional (civil) nuclear power plants, possibly higher than 20%. And their shell is a monocrystalline alloy of refractory metals based on molybdenum.

This fuel will have to operate at very high temperatures. Therefore, it was necessary to select materials that would be able to contain the negative factors associated with temperature, and at the same time allow the fuel to perform its main function - to heat the gas heat carrier, with the help of which electricity will be produced.

Refrigerator.

Gas cooling during operation nuclear facility absolutely necessary. How do you release heat in outer space? The only option is cooling by radiation. The heated surface in the void is cooled by emitting electromagnetic waves in a wide range, including visible light. The uniqueness of the project lies in the use of a special coolant - helium-xenon mixture. The installation provides a high efficiency.

Engine.

The principle of operation of the ion engine is as follows. A rarefied plasma is created in the gas discharge chamber with the help of anodes and a cathode block located in a magnetic field. The ions of the working medium (xenon or other substance) are "drawn out" from it by the emission electrode and are accelerated in the gap between it and the accelerating electrode.

To implement the plan, 17 billion rubles were promised in the period from 2010 to 2018. Of these funds, 7.245 billion rubles were allocated to the state corporation "Rosatom" for the creation of the reactor itself. Other 3.955 billion - FSUE "Keldysh Center" for the creation of a nuclear - power propulsion plant. Another 5.8 billion rubles - for RSC Energia, where the working appearance of the entire transport and energy module is to be formed in the same time frame.

According to plans, by the end of 2017, a nuclear power propulsion system will be prepared to complete the transport and energy module (interplanetary flight module). By the end of 2018, the nuclear power plant will be prepared for flight design tests. The project is financed from the federal budget.

It is no secret that work on the creation of nuclear rocket engines began in the United States and the USSR back in the 60s of the last century. How far have they come? And what problems did you have to face along the way?

Anatoly Koroteev: Indeed, work on the use of nuclear energy in space began and was actively pursued in our country and in the United States in the 1960s and 1970s.

Initially, the task was set to create rocket engines, which, instead of the chemical energy of combustion of fuel and oxidizer, would use the heating of hydrogen to a temperature of about 3000 degrees. But it turned out that such a direct route is still ineffective. We get high thrust for a short time, but at the same time we throw out a jet, which in the event of abnormal operation of the reactor may be radioactively contaminated.

Certain experience was accumulated, but neither we nor the Americans were able to create reliable engines at that time. They worked, but not much, because heating hydrogen to 3000 degrees in a nuclear reactor is a serious task. And besides, there were environmental problems during ground tests of such engines, since radioactive jets were released into the atmosphere. It is no longer a secret that such work was carried out at the Semipalatinsk test site specially prepared for nuclear tests, which remained in Kazakhstan.

That is, two parameters turned out to be critical - the prohibitive temperature and radiation emissions?

Anatoly Koroteev: In general, yes. Due to these and some other reasons, work in our country and in the United States was stopped or suspended - you can evaluate it in different ways. And it seemed to us unreasonable to renew them in such a, I would say, frontal way, in order to make a nuclear engine with all the already mentioned disadvantages. We have proposed a completely different approach. It differs from the old one in the same way that a hybrid car differs from a conventional one. In a normal car, the engine turns the wheels, and in hybrid cars, electricity is generated from the engine, and this electricity turns the wheels. That is, a kind of intermediate power plant is being created.

So we have proposed a scheme in which the space reactor does not heat the jet ejected from it, but generates electricity. The hot gas from the reactor turns the turbine, the turbine turns the electric generator and the compressor, which circulates the working fluid in a closed loop. The generator generates electricity for the plasma engine with a specific thrust 20 times higher than that of its chemical counterparts.

A tricky scheme. Essentially, this is a mini-nuclear power plant in space. And what are its advantages over a ramjet nuclear engine?

Anatoly Koroteev: The main thing is that the jet coming out of the new engine will not be radioactive, since a completely different working fluid passes through the reactor, which is contained in a closed loop.

In addition, with this scheme, we do not need to heat hydrogen to exorbitant values: an inert working fluid circulates in the reactor, which heats up to 1500 degrees. We are seriously simplifying our task. And as a result, we will raise the specific thrust not twice, but 20 times in comparison with chemical engines.

Another thing is also important: there is no need for complex field tests, for which the infrastructure of the former Semipalatinsk test site is needed, in particular, the bench base that remained in the city of Kurchatov.

In our case, all the necessary tests can be carried out on the territory of Russia, without getting involved in long international negotiations on the use of nuclear energy outside of their state.

Are similar works being carried out in other countries now?

Anatoly Koroteev: I had a meeting with the deputy head of NASA, we discussed issues related to the return to work on nuclear energy in space, and he said that the Americans are showing great interest in this.

It is quite possible that China can respond with vigorous actions on its part, so work must be done quickly. And not only in order to get ahead of someone by half a step.

We need to work quickly, first of all, so that in the emerging international cooperation, and de facto it is being formed, we look worthy.

I do not exclude the possibility that in the near future, international program on a nuclear space power plant similar to the currently being implemented program for controlled thermonuclear fusion.

Every few years some
new lieutenant colonel discovers "Pluto".
Then he calls the laboratory,
to find out the further fate of the nuclear ramjet.

This is a fashionable topic today, but it seems to me that a nuclear direct-flow air jet engine, because he does not need to carry a working body with him.
I suppose that the President's message was about him, but for some reason everyone today started to post about YARD ???
I'll put everything here in one place. Interesting thoughts, I tell you, appear when you read the topic. And very uncomfortable questions.

A ramjet engine (ramjet; the English term is ramjet, from ram - ram) - a jet engine, is the simplest in the class of air-jet engines (VRM) in terms of design. Refers to the type of direct reaction VRM, in which thrust is created exclusively due to the jet stream flowing out of the nozzle. The pressure increase required for the engine operation is achieved by braking the oncoming air flow. The ramjet is inoperative when low speeds flight, especially at zero speed, one or another accelerator is needed to bring it to operating power.

In the second half of the 1950s, during the Cold War era, the USA and the USSR developed projects for a ramjet with a nuclear reactor.


Photo by: Leicht modifiziert aus http://en.wikipedia.org/wiki/Image:Pluto1955.jpg

The source of energy for these ramjet engines (in contrast to the rest of the ramjet engines) is not chemical reaction combustion of fuel, and the heat generated by a nuclear reactor in the heating chamber of the working fluid. Air from the inlet in such a ramjet engine passes through the reactor core, cooling it, heats up itself to the operating temperature (about 3000 K), and then flows out of the nozzle at a rate comparable to the outflow rates for the most advanced chemical rocket engines. Possible destination aircraft with this engine:
- an intercontinental cruise launch vehicle of a nuclear charge;
- single-stage aerospace aircraft.

In both countries, compact low-resource nuclear reactors were created that fit into the dimensions of a large rocket. In the United States, under the Pluto and Tory nuclear ramjet research programs, bench firing tests of the Tory-IIC ramjet nuclear engine were carried out in 1964 (full power mode of 513 MW for five minutes with a thrust of 156 kN). Flight tests were not carried out, the program was closed in July 1964. One of the reasons for the closure of the program is the improvement of the design of ballistic missiles with chemical rocket engines, which fully ensured the solution of combat missions without the use of schemes with relatively expensive nuclear ramjet engines.
It is not customary to talk about the second in Russian sources now ...

The Pluto project was to use low-altitude flight tactics. This tactic ensured stealth from the radars of the USSR air defense system.
To achieve the speed at which a ramjet engine would operate, Pluto had to be launched from the ground using a package of conventional rocket boosters. The launch of the nuclear reactor began only after the "Pluto" reached cruising altitude and sufficiently removed from populated areas. The nuclear engine, giving an almost unlimited range, allowed the rocket to fly over the ocean in circles, awaiting the order to switch to supersonic speed to the target in the USSR.

Draft design SLAM

The decision was made to conduct a static test of a full-scale reactor, which was intended for a ramjet engine.
Since after launch the Pluto reactor became extremely radioactive, its delivery to the test site was carried out via a specially built fully automated railway line. On this line, the reactor travels a distance of about two miles, which separates the static test bench and the massive "demolition" building. In the building, the "hot" reactor was dismantled for inspection using remotely controlled equipment. Scientists from Livermore monitored the testing process using a television system that was housed in a tin hangar far from the test bench. Just in case, the hangar was equipped with an anti-radiation shelter with a two-week supply of food and water.
Just to supply the concrete needed to build the walls of the demolition building (six to eight feet thick), the United States government acquired an entire mine.
Millions of pounds of compressed air were stored in pipes used in oil production, a total length of 25 miles. This compressed air was supposed to be used to simulate the conditions in which a ramjet engine finds itself during flight at cruising speed.
To ensure high air pressure in the system, the laboratory borrowed giant compressors from a submarine base in Groton, Connecticut.
To carry out the test, during which the installation worked at full power for five minutes, it was required to drive a ton of air through steel tanks, which were filled with more than 14 million steel balls, 4 cm in diameter. These tanks were heated to 730 degrees using heating elements. in which oil was burned.

Installed on a railway platform, the Tori-2C is ready for successful testing. May 1964

On May 14, 1961, engineers and scientists in the hangar where the experiment was controlled held their breath - the world's first nuclear ramjet engine mounted on a bright red railway platform announced its birth with a loud roar. Tori-2A was launched for only a few seconds, during which it did not develop its rated power. However, the test was believed to be successful. The most important thing was that the reactor did not ignite, which was highly feared by some representatives of the atomic energy committee. Almost immediately after the tests, Merkle began work on the creation of the second Tory reactor, which was supposed to have more power with less weight.
Work on Tory-2B did not advance beyond the drawing board. Instead, the Livermores immediately built Tory-2C, which broke the silence of the desert three years after testing the first reactor. A week later, the reactor was restarted and operated at full power (513 megawatts) for five minutes. It turned out that the radioactivity of the exhaust is much less than expected. These tests were also attended by Air Force generals and officials from the Atomic Energy Committee.

At this time, customers from the Pentagon, who financed the "Pluto" project, began to overcome doubts. Since the missile was launched from the territory of the United States and flew over the territory of the American allies at low altitude in order to avoid detection by the USSR air defense systems, some military strategists wondered whether the missile would pose a threat to the allies? Even before the Pluto rocket drops bombs on the enemy, it will first stun, crush, and even irradiate allies. (It was expected that from Pluto flying overhead, the noise level on the ground would be about 150 decibels. For comparison, the noise level of the rocket that sent the Americans to the Moon (Saturn V) at full thrust was 200 decibels). Of course, ruptured eardrums would be the least problem if you were under a naked reactor flying over your head that roasted you like a chicken with gamma and neutron radiation.

Tori-2C

Although the creators of the rocket argued that Pluto was inherently also elusive, military analysts expressed bewilderment - how something so noisy, hot, large and radioactive could go unnoticed for the time it takes to complete a mission. At the same time, the US Air Force had already begun to deploy Atlas and Titan ballistic missiles, which were capable of reaching targets several hours earlier than the flying reactor, and the USSR anti-missile system, the fear of which was the main impetus for the creation of Pluto. , and did not become a hindrance to ballistic missiles, despite successful test interceptions. The critics of the project came up with their own decoding of the SLAM acronym - slow, low, and messy - slow, low and dirty. After the successful tests of the Polaris missile, the fleet, which initially showed interest in using missiles for launches from submarines or ships, also began to leave the project. Finally, the cost of each rocket was $ 50 million. Suddenly, Pluto became a technology with no application, a weapon that lacked suitable targets.

However, the final nail in Pluto's coffin was just one question. It is so deceptively simple that one can excuse the Livermore people for deliberately not paying attention to it. “Where to conduct flight tests of the reactor? How to convince people that during the flight the rocket will not lose control and fly over Los Angeles or Las Vegas at low altitude? " Asked Jim Hadley, a physicist at the Livermore laboratory, who worked to the very end on Project Pluto. Currently, he is engaged in detecting nuclear tests, which are being carried out in other countries, for Unit Z. According to Hadley himself, there were no guarantees that the rocket would not get out of control and turn into a flying Chernobyl.
Several options for solving this problem have been proposed. One is Pluto's launch near Wake Island, where the rocket would fly in eights over the United States' portion of the ocean. "Hot" rockets were supposed to be dumped at a depth of 7 kilometers in the ocean. However, even when the Atomic Energy Commission persuaded people to think of radiation as a limitless source of energy, the proposal to dump many radiation-contaminated missiles into the ocean was enough to stop the work.
On July 1, 1964, seven years and six months after the start of work, the Pluto project was closed by the Atomic Energy Commission and the Air Force.

Every few years, Hadley said, a new Air Force lieutenant colonel discovers Pluto. After that, he calls the laboratory to find out the further fate of the nuclear ramjet. The lieutenant colonels' enthusiasm disappears immediately after Hadley talks about the problems with radiation and flight tests. Nobody called Hadley more than once.
If someone wants to bring "Pluto" back to life, then perhaps he will be able to find a few recruits in Livermore. However, there won't be many of them. The idea of ​​what could have become a hell of an insane weapon is best left behind.

SLAM missile specifications:
Diameter - 1500 mm.
Length - 20,000 mm.
Weight - 20 tons.
The radius of action is not limited (theoretically).
The speed at sea level is Mach 3.
Armament - 16 thermonuclear bombs (power of each 1 megaton).
The engine is a nuclear reactor (power 600 megawatts).
Guidance system - inertial + TERCOM.
The maximum sheathing temperature is 540 degrees Celsius.
Airframe material - high temperature, stainless steel Rene 41.
Sheathing thickness - 4 - 10 mm.

Nevertheless, a nuclear ramjet is promising as a propulsion system for single-stage aerospace aircraft and high-speed intercontinental heavy transport aviation... This is facilitated by the possibility of creating a nuclear ramjet, capable of operating at subsonic and zero flight speeds in the rocket engine mode, using the onboard reserves of the working fluid. That is, for example, an aerospace plane with a nuclear ramjet engine starts (including takes off), supplying a working fluid to the engines from the onboard (or outboard) tanks and, having already reached speeds from M = 1, switches to using atmospheric air.

As the President of the Russian Federation V.V. Putin stated, at the beginning of 2018, “a successful launch of a cruise missile took place with nuclear power plant". Moreover, according to him, the range of such a cruise missile is "unlimited."

I wonder in which region the tests were carried out and why they were slammed by the relevant monitoring services for nuclear tests. Or is the autumn emission of ruthenium-106 in the atmosphere somehow connected with these tests? Those. Chelyabinsk residents were not only sprinkled with ruthenium, but also fried?
And where did this rocket fall, you can find out? Simply put, where was the nuclear reactor split? Which training ground? On New Earth?

**************************************** ********************

Now let's read a little about nuclear rocket engines, although this is a completely different story.

A nuclear rocket engine (NRM) is a type of rocket engine that uses the energy of fission or nuclear fusion to create jet thrust. They are liquid (heating a liquid working fluid in a heating chamber from a nuclear reactor and gas removal through a nozzle) and pulse-explosive (low-power nuclear explosions at an equal time interval).
A traditional NRE as a whole is a construction of a heating chamber with a nuclear reactor as a heat source, a working fluid supply system and a nozzle. The working fluid (usually hydrogen) is supplied from the tank to the reactor core, where, passing through the channels heated by the nuclear decay reaction, it is heated to high temperatures and then ejected through the nozzle, creating a jet thrust. There are various designs of NRE: solid-phase, liquid-phase and gas-phase - corresponding to the aggregate state of nuclear fuel in the reactor core - solid, melt or high-temperature gas (or even plasma).


East. https://commons.wikimedia.org/w/index.php?curid=1822546

RD-0410 (GRAU index - 11B91, also known as "Irgit" and "IR-100") - the first and only Soviet nuclear rocket engine in 1947-78. Was developed in design bureau"Khimavtomatika", Voronezh.
A heterogeneous thermal reactor was used in RD-0410. The design included 37 fuel assemblies covered with thermal insulation separating them from the moderator. ProjectIt was envisaged that the hydrogen flow first passed through the reflector and the moderator, maintaining their temperature at room temperature, and then entered the core, where it was heated up to 3100 K. At the stand, the reflector and moderator were cooled by a separate hydrogen flow. The reactor has undergone a significant series of tests, but has never been tested for its full operating time. The out-of-reactor units were fully worked out.

********************************

And this is an American nuclear rocket engine. His diagram was in the title picture.


By NASA - Great Images in NASA Description, Public Domain, https://commons.wikimedia.org/w/index.php?curid=6462378

NERVA (Nuclear Engine for Rocket Vehicle Application) was a joint program of the US Atomic Energy Commission and NASA to create a nuclear rocket engine (NRM), which lasted until 1972.
NERVA demonstrated that the NRM is fully operational and suitable for space exploration, and in late 1968 SNPO confirmed that the newest modification of NERVA, NRX / XE, meets the requirements for a manned mission to Mars. Although the NERVA engines were built and tested to the greatest extent possible and deemed ready to be installed on a spacecraft, much of the US space program was canceled by the Nixon administration.

NERVA has been rated by AEC, SNPO and NASA as a highly successful program that has met or exceeded its objectives. the main objective the program was to "create a technical base for nuclear rocket propulsion systems to be used in the design and development of propulsion systems for space missions ". Almost all space projects using NRE are based on NERVA NRX or Pewee designs.

Missions to Mars caused the demise of NERVA. Members of Congress from both political parties decided that a manned mission to Mars would be a tacit commitment for the United States to support the costly space race for decades. Each year the RIFT program was delayed and NERVA's goals became more complex. In the end, although the NERVA engine passed many successful tests and had strong support from Congress, it never left Earth.

In November 2017, the China Aerospace Science and Technology Corporation (CASC) published a roadmap for the development of the PRC space program for the period 2017-2045. It provides, in particular, the creation of a reusable ship powered by a nuclear rocket engine.

Found an interesting article. In general, atomic spaceships have always interested me. This is the future of astronautics. Extensive work on this topic was carried out in the USSR as well. The article is just about them.

Atomic-powered space. Dreams and Reality.

Doctor of physico-mathematical sciences Yu. Ya. Stavisskiy

In 1950, I defended my degree in physics engineering at the Moscow Mechanical Institute (MMI) of the Ministry of Ammunition. Five years earlier, in 1945, the Faculty of Engineering and Physics was formed there, preparing specialists for a new industry, the tasks of which were mainly the production of nuclear weapons. The faculty was unmatched. Along with fundamental physics in the volume of university courses (methods of mathematical physics, theory of relativity, quantum mechanics, electrodynamics, statistical physics and others), we were taught a full range of engineering disciplines: chemistry, metallurgy, resistance of materials, theory of mechanisms and machines, etc. physicist Alexander Ilyich Leipunsky, the Faculty of Engineering and Physics of MMI grew over time into the Moscow Engineering Physics Institute (MEPhI). Another Faculty of Engineering and Physics, which also later merged into MEPhI, was formed in the Moscow energy institute(MPEI), but if in MMI the main emphasis was on fundamental physics, then in Energetic - on thermal and electrophysics.

We studied quantum mechanics from the book by Dmitry Ivanovich Blokhintsev. Imagine my surprise when, during the assignment, I was sent to work for him. I, an avid experimenter (as a child, dismantled all the clocks in the house), and suddenly I get to a famous theorist. I was seized by a slight panic, but upon arrival at the place - "Object B" of the USSR Ministry of Internal Affairs in Obninsk - I immediately realized that I was worried in vain.

By this time, the main theme of "Object B", which until June 1950 was actually headed by A.I. Leipunsky, has already formed. Here they created reactors with expanded reproduction of nuclear fuel - "fast breeders". As director, Blokhintsev initiated the development of a new direction - the creation of atomic-powered engines for space flights. The mastery of space was an old dream of Dmitry Ivanovich, even in his youth he corresponded and met with K.E. Tsiolkovsky. I think that understanding the gigantic potentialities of nuclear energy, in terms of calorific value millions of times higher than the best chemical fuels, determined the life path of D.I. Blokhintsev.
“You can't see a face face to face” ... In those years, we did not understand a lot. Only now, when the opportunity has finally appeared to compare the deeds and fates of outstanding scientists of the Physics and Power Engineering Institute (IPPE) - the former "Object B", renamed on December 31, 1966 - a correct, it seems to me, understanding of the ideas that drove them at that time is taking shape. ... With all the variety of cases that the institute had to deal with, it is possible to single out the priority scientific directions that turned out to be in the sphere of interests of its leading physicists.

The main interest of the AIL (as the institute called Alexander Ilyich Leipunsky behind his back) is the development of global energy based on fast breeder reactors (nuclear reactors that have no restrictions on the resources of nuclear fuel). It is difficult to overestimate the significance of this truly "cosmic" problem, to which he devoted the last quarter of a century of his life. Leipunsky spent a lot of efforts on the country's defense, in particular on the creation of atomic engines for submarines and heavy aircraft.

The interests of D.I. Blokhintsev (the nickname "DI" stuck to him) were aimed at solving the problem of using nuclear energy for space flights. Unfortunately, in the late 1950s, he was forced to leave this job and head the creation of an international scientific center - the Joint Institute for Nuclear Research in Dubna. There he was engaged in pulsed fast reactors - the IBR. This was the last big thing in his life.

One goal, one team

DI. Blokhintsev, who taught at Moscow State University in the late 1940s, noticed there, and then invited to work in Obninsk the young physicist Igor Bondarenko, who literally raved about atomic-powered spaceships. Its first scientific advisor was A.I. Leipunsky, and Igor, naturally, dealt with his subject - fast breeders.

Under D.I. Blokhintsev, a group of scientists formed around Bondarenko, who united to solve the problems of using atomic energy in space. In addition to Igor Ilyich Bondarenko, the group included: Viktor Yakovlevich Pupko, Edwin Alexandrovich Stumbur and the author of these lines. Igor was the main ideologist. Edwin conducted experimental studies of ground-based models of nuclear reactors in space installations. I dealt mainly with “low thrust” rocket engines (thrust in them is created by a kind of accelerator - “ion propulsion device”, which is powered by energy from a space nuclear power plant). We investigated the processes
flowing in ion propellers, on ground stands.

On Victor Pupko (in the future
he became the head of the space technology department of the IPPE) there was a lot of organizational work. Igor Ilyich Bondarenko was an outstanding physicist. He subtly felt the experiment, set up simple, elegant and very effective experiments. I think, like no other experimenter, and perhaps even a few theoreticians, “felt” fundamental physics. Always responsive, open and benevolent, Igor was truly the soul of the institute. To this day, IPPE has been living with his ideas. Bondarenko lived unjustifiably short life... In 1964, at the age of 38, he died tragically due to medical error. As if God, seeing how much man had done, decided that it was already too much and ordered: "Enough."

It is impossible not to recall another unique person - Vladimir Aleksandrovich Malykh, a technologist "from God", a modern Leskovsky Lefty. If the “products” of the above-mentioned scientists were mainly ideas and calculated estimates of their reality, then Malykh's works always had a way out “in metal”. His technological sector, which at the time of the IPPE's heyday numbered more than two thousand employees, could do, without exaggeration, everything. Moreover, he himself has always played a key role.

V.A. Malykh started out as a laboratory assistant at the Research Institute of Nuclear Physics at Moscow State University, having three courses in physics at his heart - the war did not allow him to finish his studies. In the late 1940s, he managed to create a technology for the manufacture of technical ceramics based on beryllium oxide, a unique material, a dielectric with high thermal conductivity. Before Malykh, many unsuccessfully fought over this problem. A fuel cell based on serial of stainless steel and natural uranium, which he developed for the first nuclear power plant, is a miracle for that and even today. Or the thermoemission fuel cell of a reactor-electric generator designed by Malykh for powering spacecraft - a "garland". Until now, nothing better has appeared in this area. Malykh's creations were not demonstration toys, but elements of nuclear technology. They worked for months and years. Vladimir Aleksandrovich became a doctor of technical sciences, laureate of the Lenin Prize, Hero of Socialist Labor. In 1964, he tragically died from the consequences of a military shock.

Step by step

S.P. Korolev and D.I. Blokhintsev have long cherished the dream of a manned flight into space. Close working ties have been established between them. But in the early 1950s, at the height of the Cold War, funds were spared only for military purposes. Rocket technology was considered only as a carrier of nuclear charges, and they did not even think about satellites. Meanwhile, Bondarenko, knowing about the latest achievements of rocket scientists, persistently advocated the creation of an artificial Earth satellite. Subsequently, no one remembered this.

The story of the creation of the rocket, which lifted into space the first cosmonaut of the planet, Yuri Gagarin, is curious. It is associated with the name of Andrei Dmitrievich Sakharov. In the late 1940s, he developed a combined fission-thermonuclear charge - a "puff", apparently, independently of the "father of the hydrogen bomb" Edward Teller, who proposed a similar product called an "alarm clock". However, Teller soon realized that the nuclear charge of such a scheme would have a “limited” power, no more than ~ 500 kilotons of tol equivalent. This is not enough for an “absolute” weapon, so the “alarm clock” was abandoned. In the Soviet Union, in 1953, Sakharov's puff RDS-6s was blown up.

After successful tests and the election of Sakharov to the academician, the then head of the Ministry of Medium Machine Building V.A. Malyshev invited him to his place and set the task to determine the parameters of the next generation bomb. Andrei Dmitrievich appreciated (without detailed study) the weight of the new, much more powerful charge. Sakharov's report formed the basis of the decree of the Central Committee of the CPSU and the Council of Ministers of the USSR, which obliged S.P. Korolev to develop a ballistic launch vehicle for this charge. It was this R-7 rocket called Vostok that launched an artificial Earth satellite into orbit in 1957 and a spacecraft with Yuri Gagarin in 1961. It was no longer planned to use it as a carrier of a heavy nuclear charge, since the development of thermonuclear weapons took a different path.

At the initial stage of the space nuclear program, the IPPE, together with the design bureau V.N. Chelomeya developed a nuclear cruise missile. This direction did not develop for long and ended with calculations and testing of engine elements created in the department of V.A. Malykha. In fact, it was about a low-flying unmanned aircraft with a ramjet nuclear engine and a nuclear warhead (a kind of nuclear analogue of the "buzzing bug" - the German V-1). The system was launched using conventional rocket boosters. After reaching the set speed, the thrust was created by atmospheric air heated by the chain reaction of fission of beryllium oxide impregnated with enriched uranium.

Generally speaking, the ability of a rocket to perform a particular astronautical task is determined by the speed that it acquires after using the entire stock of the working fluid (fuel and oxidizer). It is calculated by the Tsiolkovsky formula: V = c × lnMn / Mk, where c is the outflow velocity of the working fluid, and Mn and Mk are the initial and final mass of the rocket. In conventional chemical rockets, the flow rate is determined by the temperature in the combustion chamber, the type of fuel and oxidizer, and the molecular weight of the combustion products. For example, the Americans used hydrogen as fuel in the descent vehicle to land astronauts on the moon. The product of its combustion is water, whose molecular weight is relatively low, and the flow rate is 1.3 times higher than when burning kerosene. This is enough for the descent vehicle with the astronauts to reach the surface of the Moon and then return them to the orbit of its artificial satellite. At Korolev, work with hydrogen fuel was suspended due to an accident with fatalities. We did not have time to create a lunar descent vehicle for humans.

One of the ways to significantly increase the rate of expiration is the creation of nuclear thermal missiles. We had ballistic atomic missiles (BAR) with a range of several thousand kilometers (a joint project of OKB-1 and IPPE), while the Americans had similar systems of the Kiwi type. The engines were tested at test sites near Semipalatinsk and in Nevada. The principle of their operation is as follows: hydrogen is heated in a nuclear reactor to high temperatures, passes into an atomic state and already in this form flows out of the rocket. In this case, the outflow velocity is increased by more than four times in comparison with a chemical hydrogen rocket. The question was to find out to what temperature hydrogen can be heated in a solid fuel cell reactor. Calculations gave about 3000 ° K.

At NII-1, whose scientific director was Mstislav Vsevolodovich Keldysh (then president of the USSR Academy of Sciences), the department of V.M. Ievlev, with the participation of IPPE, was engaged in an absolutely fantastic scheme - a gas-phase reactor in which a chain reaction proceeds in a gas mixture of uranium and hydrogen. From such a reactor, hydrogen flows out ten times faster than from a solid fuel, while uranium is separated and remains in the core. One of the ideas involved the use of centrifugal separation, when a hot gas mixture of uranium and hydrogen is “swirled” by incoming cold hydrogen, as a result of which uranium and hydrogen are separated, like in a centrifuge. Ievlev tried, in fact, to directly reproduce the processes in the combustion chamber of a chemical rocket, using as a source of energy not the heat of combustion of the fuel, but chain reaction division. This paved the way for the full use of the energy intensity of atomic nuclei. But the question of the possibility of the outflow of pure hydrogen (without uranium) from the reactor remained unresolved, not to mention the technical problems associated with the retention of high-temperature gas mixtures at pressures of hundreds of atmospheres.

IPPE's work on ballistic atomic missiles was completed in 1969-1970 with “fire tests” at the Semipalatinsk test site of a prototype nuclear rocket engine with solid fuel cells. It was created by IPPE in cooperation with A.D. Konopatov, Moscow Research Institute-1 and a number of other technology groups. The basis of the engine with a thrust of 3.6 tons was an IR-100 nuclear reactor with fuel cells made of a solid solution of uranium carbide and zirconium carbide. The hydrogen temperature reached 3000 ° K at a reactor power of ~ 170 MW.

Low-thrust nuclear missiles

Until now, we have been talking about rockets with a thrust exceeding their weight, which could be launched from the surface of the Earth. In such systems, an increase in the flow rate makes it possible to reduce the stock of the working fluid, increase the payload, and abandon the multistage system. However, there are ways to achieve practically unlimited flow rates, for example, the acceleration of matter by electromagnetic fields. I have been working in this area in close contact with Igor Bondarenko for almost 15 years.

The acceleration of a rocket with an electric jet engine (ERE) is determined by the ratio of the specific power of the space nuclear power plant (KNPP) installed on them to the outflow rate. In the foreseeable future, the specific capacities of the KNPP, apparently, will not exceed 1 kW / kg. In this case, it is possible to create rockets with low thrust, tens and hundreds of times less than the weight of the rocket, and with a very low consumption of the working fluid. Such a rocket can only start from the orbit of an artificial Earth satellite and, slowly accelerating, reach high speeds.

For flights within Solar system we need rockets with an outflow speed of 50-500 km / s, and for flights to the stars - "photonic rockets" that go beyond our imagination with an outflow speed equal to the speed of light. In order to carry out a long-range space flight that is somehow reasonable in time, unimaginable specific power of power plants is required. While it is impossible to even imagine on what physical processes they can be based.

The calculations showed that during the Great Confrontation, when the Earth and Mars are closest to each other, it is possible to fly a nuclear spacecraft with a crew to Mars in one year and return it to the orbit of an artificial Earth satellite. The total weight of such a ship is about 5 tons (including the stock of the working fluid - cesium, equal to 1.6 tons). It is mainly determined by the mass of the 5 MW KNPP, and the jet thrust is determined by a two-megawatt beam of cesium ions with an energy of 7 keV *. The spacecraft starts from the orbit of an artificial satellite of the Earth, enters the orbit of the satellite of Mars, and will have to descend to its surface on a device with a hydrogen chemical engine, similar to the American lunar one.

This direction, based on technical solutions that are already possible today, was the subject of a large series of IPPE works.

Ionic movers

In those years, the ways of creating various electrojet propulsion devices for spacecraft, such as "plasma guns", electrostatic accelerators of "dust" or liquid droplets, were discussed. However, none of the ideas had a clear-cut physical basis... The find was surface ionization of cesium.

Back in the 1920s, American physicist Irving Langmuir discovered surface ionization alkali metals... When a cesium atom evaporates from the surface of a metal (in our case, tungsten), for which the work function of electrons is greater than the ionization potential of cesium, it loses a weakly bound electron in almost 100% of cases and turns out to be a singly charged ion. Thus, the surface ionization of cesium on tungsten is the physical process that makes it possible to create an ion propulsion device with almost 100% use of the working fluid and with an energy efficiency close to unity.

Our colleague Stal Yakovlevich Lebedev played an important role in the creation of models of an ion propulsion device of such a scheme. With his iron tenacity and perseverance, he overcame all obstacles. As a result, it was possible to reproduce in the metal a flat three-electrode scheme of the ion propulsion device. The first electrode is a tungsten plate approximately 10 × 10 cm in size with a potential of +7 kV, the second is a tungsten grid with a potential of -3 kV, and the third is a grid of thoriated tungsten with zero potential. The “molecular gun” produced a beam of cesium vapor, which fell through all the grids onto the surface of the tungsten plate. A balanced and calibrated metal plate, the so-called balance, was used to measure the “force,” that is, the thrust of the ion beam.

The accelerating voltage to the first grid accelerates the cesium ions to 10,000 eV, the decelerating voltage to the second slows them down to 7000 eV. This is the energy with which the ions must leave the propulsion device, which corresponds to an outflow velocity of 100 km / s. But the ion beam, limited by the space charge, cannot "go out into outer space". The volume charge of ions must be compensated for by electrons in order to form a quasi-neutral plasma, which freely spreads in space and creates a reactive thrust. The third grid (cathode) heated by the current serves as the source of electrons to compensate for the space charge of the ion beam. The second, "blocking" grid prevents electrons from getting from the cathode to the tungsten plate.

The first experience with the ion propulsion model marked the beginning of more than ten years of work. One of the latest models - with a porous tungsten emitter, created in 1965, gave a "thrust" of about 20 g at an ion beam current of 20 A, had a coefficient of energy utilization of about 90% and of matter - 95%.

Direct conversion of nuclear heat into electricity

Ways of direct conversion of nuclear fission energy into electrical energy have not yet been found. We still cannot do without an intermediate link - a heat engine. Since its efficiency is always less than unity, the “waste” heat must be disposed of somewhere. On land, in water and in the air, this is not a problem. In space, there is only one way - thermal radiation. Thus, the KNPP cannot do without a “cooler-radiator”. The radiation density is proportional to the fourth power of the absolute temperature, therefore the temperature of the radiator-refrigerator should be as high as possible. Then it will be possible to reduce the area of ​​the emitting surface and, accordingly, the mass power plant... We had an idea to use the “direct” conversion of nuclear heat into electricity, without a turbine and generator, which seemed more reliable during long-term operation at high temperatures.

From the literature, we knew about the works of A.F. Ioffe - the founder of the Soviet school of technical physics, a pioneer in the study of semiconductors in the USSR. Few people now remember about the current sources developed by him, which were used in the years of the Great Patriotic War... Then, more than one partisan detachment had a connection with the mainland thanks to the "kerosene" TEGs - Ioffe's thermoelectric generators. A "crown" of TEGs (it was a set of semiconductor elements) was put on a kerosene lamp, and its wires were connected to radio equipment. The “hot” ends of the elements were heated by the flame of a kerosene lamp, and the “cold” ends were cooled in air. The heat flux, passing through the semiconductor, generated an electromotive force, which was enough for a communication session, and in the intervals between them, the TEG charged the battery. When, ten years after the Victory, we visited the Moscow plant of TEGs, it turned out that they were still finding sales. At that time, many of the villagers had energy-efficient Rodina radios with direct incandescent lamps and battery operated. TEGs were often used instead.

The trouble with the kerosene TEG is its low efficiency (only about 3.5%) and low limiting temperature (350 ° K). But the simplicity and reliability of these devices attracted developers. Thus, semiconductor converters developed by the group of I.G. Gverdtsitels at the Sukhumi Physics and Technology Institute, found application in space installations of the Buk type.

At one time A.F. Ioffe proposed another thermionic converter - a diode in a vacuum. The principle of its operation is as follows: a heated cathode emits electrons, some of them, overcoming the potential of the anode, do work. Significantly higher efficiency (20-25%) was expected from this device at operating temperature above 1000 ° K. In addition, unlike a semiconductor, a vacuum diode is not afraid of neutron radiation, and it can be combined with a nuclear reactor. However, it turned out that it is impossible to implement the idea of ​​a “vacuum” Ioffe converter. As in an ion propulsion device, in a vacuum converter, you need to get rid of the space charge, but this time not ions, but electrons. A.F. Ioffe proposed to use micron gaps between the cathode and anode in a vacuum converter, which is practically impossible under conditions of high temperatures and thermal deformations. This is where cesium came in handy: one cesium ion, obtained due to surface ionization at the cathode, compensates for the volume charge of about 500 electrons! Essentially, a cesium converter is a “reversed” ion propulsion device. The physical processes in them are similar.

"Garlands" by V.A. Malykha

One of the results of the IPPE's work on thermionic converters was the creation of V.A. Small and serial production in its department of fuel elements from series-connected thermionic converters - "garlands" for the Topaz reactor. They gave up to 30 V - one hundred times more than single-element converters created by "competing organizations" - the Leningrad group of MB Barabash and later - by the Institute of Atomic Energy. This made it possible to “remove” from the reactor tens and hundreds of times more power. However, the reliability of the system, crammed with thousands of thermionic elements, raised concerns. At the same time, steam and gas turbine plants operated without interruptions, so we paid attention to the “machine” conversion of nuclear heat into electricity.

The whole difficulty was in the resource, because in deep space flights, turbine generators should work for a year, two, or even several years. To reduce wear, the “revolutions” (turbine speed) should be made as low as possible. On the other hand, a turbine works efficiently if the speed of the gas or vapor molecules is close to the speed of its blades. Therefore, first we considered the use of the heaviest - mercury vapor. But we were frightened by the intense radiation-stimulated corrosion of iron and stainless steel, which occurred in a nuclear reactor cooled with mercury. In two weeks, corrosion “ate up” the fuel elements of the Clementine experimental fast reactor in the Argonne Laboratory (USA, 1949) and the BR-2 reactor at the IPPE (USSR, Obninsk, 1956).

Potassium vapor turned out to be tempting. A reactor with potassium boiling in it formed the basis of the power plant of a low-thrust spacecraft that we were developing - potassium steam rotated a turbogenerator. This "machine" method of converting heat into electricity made it possible to count on an efficiency of up to 40%, while real thermionic installations gave an efficiency of only about 7%. However, KNPPs with “machine” conversion of nuclear heat into electricity have not been developed. The case ended with the release of a detailed report, in fact - a "physical note" to the technical project of a low-thrust spacecraft for a crewed flight to Mars. The project itself was never developed.

In the future, I think, interest in space flights using nuclear rocket engines simply disappeared. After the death of Sergei Pavlovich Korolev, support for the IPPE work on ion propulsion systems and "machine" nuclear power plants noticeably weakened. OKB-1 was headed by Valentin Petrovich Glushko, who had no interest in daring promising projects. The OKB Energia, which he created, built powerful chemical rockets and the Buran spacecraft that would return to Earth.

"Buk" and "Topaz" on the satellites of the "Cosmos" series

Work on the creation of a KNPP with direct conversion of heat into electricity, now as power sources for powerful radio-technical satellites (space radar stations and TV broadcasters), continued until the start of restructuring. From 1970 to 1988, about 30 radar satellites with Buk nuclear power plants with semiconductor converters and two with Topaz thermoemission plants were launched into space. "Buk", in fact, was a TEG - a semiconductor Ioffe converter, only instead of a kerosene lamp it used a nuclear reactor. It was a fast reactor with a power of up to 100 kW. The full load of highly enriched uranium was about 30 kg. Heat from the core was transferred by liquid metal - a eutectic alloy of sodium and potassium to semiconductor batteries. Electric power reached 5 kW.

Installation "Buk" under the scientific supervision of the IPPE was developed by experts from OKB-670 MM. Bondaryuk, later - NPO Krasnaya Zvezda (chief designer - GM Gryaznov). The Dnepropetrovsk design bureau Yuzhmash (chief designer - MK Yangel) was instructed to create a launch vehicle for launching the satellite into orbit.

"Buk" working hours - 1-3 months. If the installation failed, the satellite was transferred to a long-term orbit with an altitude of 1000 km. For almost 20 years of launches, there have been three cases of a satellite falling to Earth: two - into the ocean and one - on land, in Canada, in the vicinity of the Great Slave Lake. Space-954, launched on January 24, 1978, fell there. He worked for 3.5 months. The satellite's uranium elements were completely burned up in the atmosphere. On the ground, only the remains of a beryllium reflector and semiconductor batteries were found. (All of this data is given in the joint report of the US and Canadian atomic commissions on Operation Morning Light.)

A thermal reactor with a power of up to 150 kW was used in the Topaz thermal emission nuclear power plant. The full load of uranium was about 12 kg - significantly less than that of the Buk. The core of the reactor was fuel elements - "garlands", developed and manufactured by Malykh's group. They were a chain of thermoelements: the cathode was a “thimble” of tungsten or molybdenum filled with uranium oxide, and the anode was a thin-walled niobium tube cooled with liquid sodium-potassium. The cathode temperature reached 1650 ° C. The electrical power of the installation reached 10 kW.

The first flight prototype, the Kosmos-1818 satellite with the Topaz installation, entered orbit on February 2, 1987 and operated without failure for six months, until the cesium reserves were depleted. The second satellite, Cosmos-1876, was launched a year later. He worked in orbit for almost twice as long. The main developer of "Topaz" was OKB MMZ "Soyuz", headed by S.K. Tumansky (former design bureau of aircraft engine designer A.A.Mikulin).

This was in the late 1950s, when we were working on the ion propulsion system, and he was working on the third stage engine, intended for a rocket that was to fly around the moon and land on it. Memories of the Melnikov laboratory are fresh to this day. It was located in Podlipki (now the town of Korolev), on site No. 3 of OKB-1. A huge workshop with an area of ​​about 3000 m2, lined with dozens of desks with loop oscilloscopes recording on 100 mm roll paper (this was still a bygone era, today one personal computer). At the front wall of the workshop there is a stand where the combustion chamber of the "lunar" rocket engine is mounted. Oscilloscopes are connected to thousands of wires from sensors of gas velocity, pressure, temperature and other parameters. The day starts at 9.00 with the ignition of the engine. It works for several minutes, then immediately after stopping a team of mechanics of the first shift dismantles it, carefully examines and measures the combustion chamber. At the same time, oscilloscope tapes are analyzed and recommendations for design changes are made. The second shift - the designers and workshop workers make the recommended changes. In the third shift, a new combustion chamber and diagnostic system are being installed at the stand. A day later, at exactly 9.00 am, the next session will take place. And so without days off for weeks, months. Over 300 engine options per year!

This is how the engines of chemical rockets were created, which had to work for only 20-30 minutes. What can we say about the tests and modifications of nuclear power plants - the calculation was that they should work for more than one year. This required a truly gigantic effort.

© Oksana Viktorova / Collage / Ridus

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

"Reedus" tried to figure out which technical device the president could speak and what is his uniqueness.

Taking into account that the presentation in the Manezh was made not for the audience of technical specialists, but for the “general” public, its authors could have allowed a certain substitution of concepts, Georgy Tikhomirov, Deputy Director of the Institute of Nuclear Physics and Technology of NRNU MEPhI, does not rule out.

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

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

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

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

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

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

“The meaning of a nuclear installation during deep space flights is the presence of an energy source on board to power the systems of the vehicle for an unlimited time. In this case, there can be not only a nuclear reactor, but also radioisotope thermoelectric generators. And the meaning of such an installation on a rocket, the flight of which will not last more than a few tens of minutes, is not yet completely clear to me, ”the physicist admits.

The Manege report is only a couple of weeks late compared to NASA's February 15 announcement that the Americans are resuming nuclear rocket engine research they had abandoned half a century ago.

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