Late last year, the Russian Strategic Missile Forces tested a completely new weapon, the existence of which was previously considered impossible. The nuclear-powered cruise missile, which military experts designate 9M730, is exactly the new weapon that President Putin spoke about in his Address to the Federal Assembly. The missile test was allegedly carried out at the Novaya Zemlya test site, approximately at the end of autumn 2017, but the exact data will not be declassified soon. The rocket developer is also presumably the Novator Experimental Design Bureau (Ekaterinburg). According to competent sources, the missile hit the target in normal mode and the tests were considered completely successful. Next, alleged photographs of the launch appeared in the media (above) new rocket with nuclear power plant and even indirect confirmation related to the presence at the expected time of testing in the immediate vicinity of the test site of the Il-976 LII Gromov “flying laboratory” with Rosatom marks. However, even more questions arose. Is the declared ability of the missile to fly at an unlimited range realistic and how is it achieved?

Characteristics of a cruise missile with a nuclear power plant

The characteristics of a cruise missile with nuclear weapons, which appeared in the media immediately after Vladimir Putin’s speech, may differ from the real ones, which will be known later. To date, the following data on the size and performance characteristics of the rocket have become public:

Length
- home page- at least 12 meters,
- marching- at least 9 meters,

Rocket body diameter- about 1 meter,
Case width- about 1.5 meters,
Tail height- 3.6 - 3.8 meters

Operating principle of a Russian nuclear-powered cruise missile

The development of nuclear-powered missiles was carried out by several countries at once, and development began back in the distant 1960s. The designs proposed by the engineers differed only in details; in a simplified manner, the principle of operation can be described as follows: the nuclear reactor heats the mixture entering special containers ( different options, from ammonia to hydrogen) followed by release through nozzles under high pressure. However, the version of the cruise missile that the Russian president spoke about does not fit any of the examples of designs developed previously.

The fact is that, according to Putin, the missile has an almost unlimited flight range. This, of course, cannot be understood to mean that the missile can fly for years, but it can be regarded as a direct indication that its flight range is many times greater than the flight range of modern cruise missiles. The second point, which cannot be ignored, is also related to the declared unlimited flight range and, accordingly, the operation of the cruise missile’s power unit. For example, a heterogeneous thermal neutron reactor, tested in the RD-0410 engine, which was developed by Kurchatov, Keldysh and Korolev, had a testing life of only 1 hour, and in this case there cannot be an unlimited flight range of such a nuclear-powered cruise missile. speech.

All this suggests that Russian scientists have proposed a completely new, previously unconsidered concept of the structure, in which a substance that has a much economical resource of consumption over long distances is used for heating and subsequent ejection from the nozzle. As an example, this could be a nuclear air-breathing engine (NARE) of a completely new type, in which the working mass is atmospheric air, pumped into working tanks by compressors, heated by a nuclear installation and then released through nozzles.

It is also worth noting that the cruise missile with a nuclear power unit announced by Vladimir Putin can fly around active zones of anti-aircraft and missile defense, and also keep the path to the target at low and ultra-low altitudes. This is only possible by equipping the missile with terrain-following systems that are resistant to interference created by enemy electronic warfare systems.

Every few years some
the new lieutenant colonel discovers Pluto.
After that, he calls the laboratory,
to find out the future fate of the nuclear ramjet.

This is a fashionable topic these days, but it seems to me that a nuclear ramjet engine is much more interesting, because it does not need to carry a working fluid with it.
I assume that the President’s message was about him, but for some reason everyone started posting about the YARD today???
Let me collect everything here in one place. I’ll tell you, interesting thoughts appear when you read into a topic. And very uncomfortable questions.

A ramjet engine (ramjet engine; the English term is ramjet, from ram - ram) is a jet engine that is the simplest in the class of air-breathing jet engines (ramjet engines) in design. It belongs to the type of direct reaction jet engines, in which thrust is created solely by the jet stream flowing from the nozzle. The increase in pressure necessary for engine operation is achieved by braking the oncoming air flow. A ramjet engine is inoperative at low flight speeds, 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, ramjet designs with a nuclear reactor were developed in the USA and USSR.


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

The energy source of these ramjet engines (unlike other ramjet engines) is not the chemical reaction of fuel combustion, but the heat generated by the nuclear reactor in the heating chamber of the working fluid. The air from the input device in such a ramjet passes through the reactor core, cooling it, heats itself up to the operating temperature (about 3000 K), and then flows out of the nozzle at a speed comparable to the exhaust speeds for the most advanced chemical rocket engines. Possible purposes of an aircraft with such an engine:
- 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 big rocket. In the USA, under the Pluto and Tory nuclear ramjet research programs, bench fire tests of the Tory-IIC nuclear ramjet engine were carried out in 1964 (full power mode 513 MW for five minutes with a thrust of 156 kN). No flight tests were conducted and the program was closed in July 1964. One of the reasons for the closure of the program was 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’s not customary to talk about the second one in Russian sources now...

The Pluto project was supposed to use low-altitude flight tactics. This tactic ensured secrecy 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 Pluto reached cruising altitude and was sufficiently removed from populated areas. The nuclear engine, which gave an almost unlimited range of action, allowed the rocket to fly in circles over the ocean while awaiting the order to switch to supersonic speed towards a target in the USSR.

SLAM concept design

It was decided to conduct a static test of a full-scale reactor, which was intended for a ramjet engine.
Since the Pluto reactor became extremely radioactive after launch, it was delivered to the test site via a specially built, fully automated railway line. Along this line, the reactor moved over a distance of approximately two miles, which separated the static test stand and the massive “dismantling” building. In the building, the “hot” reactor was dismantled for inspection using remotely controlled equipment. Livermore scientists monitored the testing process using a television system located in a tin hangar far from the test stand. 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 construct the demolition building's walls (which were six to eight feet thick), the United States government purchased an entire mine.
Millions of pounds of compressed air were stored in 25 miles of oil production pipes. Given compressed air was intended 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 the submarine base in Groton, Connecticut.
The test, during which the unit ran at full power for five minutes, required forcing a ton of air through steel tanks that were filled with more than 14 million 4cm diameter steel balls. These tanks were heated to 730 degrees using heating elements, in which oil was burned.

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

On May 14, 1961, engineers and scientists in the hangar from which the experiment was controlled held their breath as 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 considered successful. The most important thing was that the reactor did not ignite, which some representatives of the Atomic Energy Committee were extremely afraid of. Almost immediately after the tests, Merkle began work on creating a second Tory reactor, which was supposed to have more power with less weight.
Work on Tori-2B has not progressed beyond the drawing board. Instead, the Livermores immediately built the 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 was significantly less than expected. These tests were also attended by Air Force generals and officials from the Atomic Energy Committee.

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

Tori-2C

Although the rocket's creators argued that Pluto was also inherently elusive, military analysts expressed bafflement at how something so noisy, hot, large and radioactive could remain undetected for as long as it took to complete its 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 before a flying reactor, and the USSR anti-missile system, the fear of which became the main impetus for the creation of Pluto. , never became an obstacle for ballistic missiles, despite the successful test interceptions. Critics of the project came up with their own decoding of the acronym SLAM - slow, low, and messy - slowly, low and dirty. After the successful testing of the Polaris missile, the Navy, which had initially expressed interest in using the missiles for launch from submarines or ships, also began to abandon the project. And finally, the cost of each rocket was 50 million dollars. Suddenly Pluto became a technology with no applications, a weapon with no viable targets.

However, the final nail in Pluto's coffin was just one question. It is so deceptively simple that the Livermoreites can be excused for deliberately not paying attention to it. “Where to conduct reactor flight tests? How do you convince people that during the flight the rocket will not lose control and fly over Los Angeles or Las Vegas at low altitude?” asked Livermore Laboratory physicist Jim Hadley, who worked on the Pluto project until the very end. He is currently engaged in detecting nuclear tests being carried out in other countries for Unit Z. By Hadley's own admission, there were no guarantees that the missile would not get out of control and turn into a flying Chernobyl.
Several solutions to this problem have been proposed. One would be a Pluto launch near Wake Island, where the rocket would fly figure-eights over the United States' portion of the ocean. “Hot” missiles were supposed to be sunk 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 rockets into the ocean was enough to stop 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, a new Air Force lieutenant colonel discovers Pluto, Hadley said. After this, he calls the laboratory to find out the further fate of the nuclear ramjet. The lieutenant colonels' enthusiasm disappears immediately after Hadley talks about problems with radiation and flight tests. No one called Hadley more than once.
If anyone wants to bring Pluto back to life, he might be able to find some recruits in Livermore. However, there won't be many of them. The idea of ​​what could become one hell of a crazy weapon is best left in the past.

Technical characteristics of the SLAM rocket:
Diameter - 1500 mm.
Length - 20000 mm.
Weight - 20 tons.
The range is unlimited (theoretically).
Speed ​​at sea level is Mach 3.
Armament - 16 thermonuclear bombs (each with a yield of 1 megaton).
Engine - nuclear reactor(power 600 megawatts).
Guidance system - inertial + TERCOM.
The maximum skin temperature is 540 degrees Celsius.
The airframe material is high-temperature Rene 41 stainless steel.
Sheathing thickness - 4 - 10 mm.

Nevertheless, the nuclear ramjet engine is promising as a propulsion system for single-stage aerospace aircraft and high-speed intercontinental heavy transport aircraft. This is facilitated by the possibility of creating a nuclear ramjet capable of operating at subsonic and zero flight speeds in rocket engine mode, using on-board propellant reserves. That is, for example, an aerospace aircraft with a nuclear ramjet starts (including takes off), supplying 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 Russian President V.V. Putin said, at the beginning of 2018, “a successful launch of a cruise missile with a nuclear power plant took place.” 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 release of ruthenium-106 in the atmosphere somehow connected with these tests? Those. Chelyabinsk residents were not only sprinkled with ruthenium, but also fried?
Can you find out where this rocket fell? Simply put, where was the nuclear reactor broken up? At what training ground? On Novaya Zemlya?

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Now let’s read a little about nuclear rocket engines, although that’s a completely different story

A nuclear rocket engine (NRE) is a type of rocket engine that uses the energy of fission or fusion of nuclei to create jet thrust. They can be liquid (heating a liquid working fluid in a heating chamber from a nuclear reactor and releasing gas through a nozzle) and pulse-explosive ( nuclear explosions low power for an equal period of time).
A traditional nuclear propulsion engine as a whole is a structure consisting 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 channels heated by the nuclear decay reaction, it is heated to high temperatures and then thrown out through the nozzle, creating jet thrust. There are various designs 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 1947-78. It was developed at the Khimavtomatika design bureau, Voronezh.
The RD-0410 used a heterogeneous thermal neutron reactor. The design included 37 fuel assemblies, covered with thermal insulation that separated them from the moderator. ProjectIt was envisaged that the hydrogen flow first passed through the reflector and moderator, maintaining their temperature at room temperature, and then entered the core, where it was heated 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. The out-of-reactor components were completely exhausted.

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


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

NERVA (Nuclear Engine for Rocket Vehicle Application) is a joint program of the US Atomic Energy Commission and NASA to create a nuclear rocket engine (NRE), which lasted until 1972.
NERVA demonstrated that the NER was viable and suitable for space exploration, and in late 1968 the SNPO confirmed that NERVA's newest modification, the NRX/XE, met the requirements for a manned mission to Mars. Although the NERVA engines were built and tested to the maximum extent possible and were considered ready for installation on a spacecraft, most of the American space program was canceled by the Nixon administration.

NERVA has been rated by the AEC, SNPO, and NASA as a highly successful program that has met or exceeded its goals. Main goal program was to "establish 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 nuclear propulsion engines are based on NERVA NRX or Pewee designs.

Mars missions were responsible for NERVA's demise. Members of Congress from both political parties have 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. After all, although the NERVA engine had many successful tests and 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 China's space program for the period 2017-2045. It provides, in particular, for the creation of a reusable ship powered by a nuclear rocket engine.

Skeptics argue that the creation of a nuclear engine is not a significant progress in the field of science and technology, but only a “modernization of a steam boiler”, where instead of coal and firewood, uranium acts as fuel, and hydrogen acts as a working fluid. Is the NRE (nuclear jet engine) so hopeless? Let's try to figure it out.

First rockets

All the achievements of mankind in the exploration of near-Earth space can be safely attributed to chemical jet engines. The operation of such power units is based on the conversion of the energy of the chemical reaction of fuel combustion in an oxidizer into the kinetic energy of the jet stream, and, consequently, the rocket. The fuel used is kerosene, liquid hydrogen, heptane (for liquid propellant rocket engines (LPRE)) and a polymerized mixture of ammonium perchlorate, aluminum and iron oxide (for solid propellant rocket engines (SDRE)).

It is common knowledge that the first rockets used for fireworks appeared in China in the second century BC. They rose into the sky thanks to the energy of powder gases. The theoretical research of the German gunsmith Konrad Haas (1556), Polish general Kazimir Semenovich (1650), and Russian Lieutenant General Alexander Zasyadko made a significant contribution to the development of rocket technology.

American received a patent for the invention of the first rocket with a liquid-propellant engine scientist Robert Goddard. His apparatus, weighing 5 kg and about 3 m long, running on gasoline and liquid oxygen, took 2.5 s in 1926. flew 56 meters.

Chasing speed

Serious experimental work on the creation of serial chemical jet engines started in the 30s of the last century. In the Soviet Union, V. P. Glushko and F. A. Tsander are rightfully considered the pioneers of rocket engine construction. With their participation, the RD-107 and RD-108 power units were developed, which ensured the USSR's primacy in space exploration and laid the foundation for Russia's future leadership in the field of manned space exploration.

During the modernization of the liquid-turbine engine, it became clear that the theoretical maximum speed the jet stream will not be able to exceed 5 km/s. This may be enough to study near-Earth space, but flights to other planets, and even more so to the stars, will remain a pipe dream for humanity. As a result, already in the middle of the last century, projects for alternative (non-chemical) rocket engines began to appear. The most popular and promising installations were those using the energy of nuclear reactions. The first experimental samples of nuclear space engines (NRE) in the Soviet Union and the USA passed test tests back in 1970. However, after the Chernobyl disaster, under public pressure, work in this area was suspended (in the USSR in 1988, in the USA - since 1994).

The operation of nuclear power plants is based on the same principles as thermochemical ones. The only difference is that the heating of the working fluid is carried out by the energy of decay or fusion of nuclear fuel. The energy efficiency of such engines significantly exceeds chemical ones. For example, the energy that can be released by 1 kg of the best fuel (a mixture of beryllium with oxygen) is 3 × 107 J, while for polonium isotopes Po210 this value is 5 × 1011 J.

The released energy in a nuclear engine can be used in various ways:

heating the working fluid emitted through the nozzles, as in a traditional liquid-propellant rocket engine, after conversion into electricity, ionizing and accelerating particles of the working fluid, creating an impulse directly by fission or synthesis products. Even ordinary water can act as a working fluid, but the use of alcohol will be much more effective, ammonia or liquid hydrogen. Depending on the state of aggregation of the fuel for the reactor, nuclear rocket engines are divided into solid-, liquid- and gas-phase. The most developed nuclear propulsion engine is with a solid-phase fission reactor, using fuel rods (fuel elements) used in nuclear power plants as fuel. The first such engine, as part of the American Nerva project, underwent ground testing in 1966, operating for about two hours.

Design features

At the heart of any nuclear space engine lies a reactor consisting of a core and a beryllium reflector located in a power housing. The fission of atoms of a combustible substance, usually uranium U238, enriched in U235 isotopes, occurs in the core. To impart certain properties to the decay process of nuclei, moderators are also located here - refractory tungsten or molybdenum. If the moderator is included in the fuel rods, the reactor is called homogeneous, and if it is placed separately, it is called heterogeneous. The nuclear engine also includes a working fluid supply unit, controls, shadow radiation protection, and a nozzle. Structural elements and components of the reactor, which experience high thermal loads, are cooled by the working fluid, which is then pumped into the fuel assemblies by a turbopump unit. Here it is heated to almost 3,000˚C. Flowing through the nozzle, the working fluid creates jet thrust.

Typical reactor controls are control rods and turntables made of a neutron-absorbing substance (boron or cadmium). The rods are placed directly in the core or in special reflector niches, and the rotary drums are placed on the periphery of the reactor. By moving the rods or turning the drums, the number of fissile nuclei per unit time is changed, regulating the level of energy release of the reactor, and, consequently, its thermal power.

To reduce the intensity of neutron and gamma radiation, which is dangerous for all living things, primary reactor protection elements are placed in the power building.

Increased efficiency

A liquid-phase nuclear engine is similar in operating principle and design to solid-phase ones, but the liquid state of the fuel makes it possible to increase the temperature of the reaction, and, consequently, the thrust of the power unit. So, if for chemical units (liquid turbojet engines and solid propellant rocket engines) the maximum specific impulse (jet flow velocity) is 5,420 m/s, for solid-phase nuclear engines and 10,000 m/s is far from the limit, then the average value of this indicator for gas-phase nuclear propellant engines lies in the range 30,000 - 50,000 m/s.

There are two types of gas-phase nuclear engine projects:

An open cycle, in which a nuclear reaction occurs inside a plasma cloud of a working fluid held by an electromagnetic field and absorbing all the generated heat. Temperatures can reach several tens of thousands of degrees. In this case, the active region is surrounded by a heat-resistant substance (for example, quartz) - a nuclear lamp that freely transmits emitted energy. In installations of the second type, the temperature of the reaction will be limited by the melting point of the flask material. At the same time, the energy efficiency of a nuclear space engine is slightly reduced (specific impulse up to 15,000 m/s), but efficiency and radiation safety are increased.

Practical achievements

Formally, the American scientist and physicist Richard Feynman is considered to be the inventor of the nuclear power plant. Start of large-scale development and creation work nuclear engines for spacecraft as part of the Rover program was given at the Los Alamos Research Center (USA) in 1955. American inventors preferred installations with a homogeneous nuclear reactor. The first experimental sample of "Kiwi-A" was assembled at a plant at the nuclear center in Albuquerque (New Mexico, USA) and tested in 1959. The reactor was placed vertically on the stand with the nozzle upward. During the tests, a heated stream of spent hydrogen was released directly into the atmosphere. And although the rector worked at low power for only about 5 minutes, the success inspired the developers.

In the Soviet Union, a powerful impetus for such research was given by the meeting of the “three great Ks” that took place in 1959 at the Institute of Atomic Energy - the creator of the atomic bomb I.V. Kurchatov, the chief theorist of Russian cosmonautics M.V. Keldysh and the general designer of Soviet rockets S.P. Queen. Unlike the American model, the Soviet RD-0410 engine, developed at the design bureau of the Khimavtomatika association (Voronezh), had a heterogeneous reactor. Fire tests took place at a training ground near Semipalatinsk in 1978.

It is worth noting that quite a lot of theoretical projects were created, but the matter never came to practical implementation. The reasons for this were the presence of a huge number of problems in materials science, and a lack of human and financial resources.

For note: an important practical achievement was the flight testing of nuclear-powered aircraft. In the USSR, the most promising was the experimental strategic bomber Tu-95LAL, in the USA - the B-36.

Project "Orion" or pulsed nuclear rocket engines

For flights in space, a pulsed nuclear engine was first proposed to be used in 1945 by an American mathematician of Polish origin, Stanislaw Ulam. In the next decade, the idea was developed and refined by T. Taylor and F. Dyson. The bottom line is that the energy of small nuclear charges, detonated at some distance from the pushing platform on the bottom of the rocket, imparts great acceleration to it.

During the Orion project, launched in 1958, it was planned to equip a rocket with just such an engine capable of delivering people to the surface of Mars or the orbit of Jupiter. The crew, located in the bow compartment, would be protected from the destructive effects of gigantic accelerations by a damping device. The result of detailed engineering work was marching tests of a large-scale mock-up of the ship to study flight stability (ordinary explosives were used instead of nuclear charges). Due to the high cost, the project was closed in 1965.

Similar ideas for creating an “explosive aircraft” were expressed by Soviet academician A. Sakharov in July 1961. To launch the ship into orbit, the scientist proposed using conventional liquid-propellant rocket engines.

Alternative projects

A huge number of projects never went beyond theoretical research. Among them there were many original and very promising ones. The idea of ​​a nuclear power plant based on fissile fragments is confirmed. Design features and the design of this engine makes it possible to do without a working fluid at all. The jet stream, which provides the necessary thrust characteristics, is formed from spent nuclear material. The reactor is based on rotating disks with subcritical nuclear mass (atomic fission coefficient less than unity). When rotating in the sector of the disk located in the core, a chain reaction is started and decaying high-energy atoms are directed into the engine nozzle, forming a jet stream. The preserved intact atoms will take part in the reaction at the next revolutions of the fuel disk.

Projects of a nuclear engine for ships performing certain tasks in near-Earth space, based on RTGs (radioisotope thermoelectric generators), are quite workable, but such installations are of little promise for interplanetary, and even more so interstellar flights.

Nuclear fusion engines have enormous potential. Already at the present stage of development of science and technology, a pulsed installation is quite feasible, in which, like the Orion project, thermonuclear charges will be detonated under the bottom of the rocket. However, many experts consider the implementation of controlled nuclear fusion to be a matter of the near future.

Advantages and disadvantages of nuclear powered engines

The indisputable advantages of using nuclear engines as power units for spacecraft include their high energy efficiency, providing high specific impulse and good thrust performance (up to a thousand tons in airless space), and impressive energy reserves during autonomous operation. The current level of scientific and technological development makes it possible to ensure the comparative compactness of such an installation.

The main drawback of nuclear propulsion engines, which caused the curtailment of design and research work, is the high radiation hazard. This is especially true when conducting ground-based fire tests, as a result of which radioactive gases, uranium compounds and its isotopes, and the destructive effects of penetrating radiation may enter the atmosphere along with the working fluid. For the same reasons, it is unacceptable to launch a spacecraft equipped with a nuclear engine directly from the surface of the Earth.

Present and future

According to the academician of the Russian Academy of Sciences, general director"Keldysh Center" Anatoly Koroteev, a fundamentally new type of nuclear engine in Russia will be created in the near future. The essence of the approach is that the energy of the space reactor will be directed not to directly heating the working fluid and forming a jet stream, but to produce electricity. The role of the mover in the installation is given to plasma engine, the specific thrust of which is 20 times higher than the thrust of chemical rocket vehicles existing today. The head enterprise of the project is a division of the state corporation Rosatom, JSC NIKIET (Moscow).

Full-scale prototype tests were successfully completed back in 2015 on the basis of NPO Mashinostroeniya (Reutov). The date for the start of flight testing of the nuclear power plant is November of this year. The most important elements and systems will have to be tested, including on board the ISS.

The new Russian nuclear engine operates in a closed cycle, which completely eliminates radioactive substances into the surrounding space. The mass and dimensional characteristics of the main elements of the power plant ensure its use with existing domestic Proton and Angara launch vehicles.

Sergeev Alexey, 9 “A” class, Municipal Educational Institution “Secondary School No. 84”

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

Head: , physics teacher, Municipal Educational Institution “Secondary School No. 84” CATO Seversk

Introduction

Propulsion systems on board a spacecraft are designed to create thrust or momentum. According to the type of thrust used, the propulsion system is divided into chemical (CHRD) and non-chemical (NCRD). CRDs are divided into liquid propellant engines (LPRE), solid propellant rocket engines (solid propellant engines) and combined rocket engines (RCR). In turn, non-chemical propulsion systems are divided into nuclear (NRE) and electric (EP). The great scientist Konstantin Eduardovich Tsiolkovsky a century ago created the first model of a propulsion system that worked on solid and liquid fuel. Afterwards, in the second half of the 20th century, thousands of flights were carried out using mainly liquid propellant engines and solid propellant rocket engines.

However, at present, for flights to other planets, not to mention the stars, the use of liquid propellant rocket engines and solid propellant rocket engines is becoming increasingly unprofitable, although many rocket engines have been developed. Most likely, the capabilities of liquid propellant rocket engines and solid propellant rocket engines have completely exhausted themselves. The reason here is that the specific impulse of all chemical thrusters is low and does not exceed 5000 m/s, which requires long-term operation of the thruster and, accordingly, large reserves of fuel for the development of sufficiently high speeds, or, as is customary in astronautics, large values ​​of the Tsiolkovsky number are required, t .e. the ratio of the mass of the fueled rocket to the mass of the empty one. So LV Energiya, launching 100 tons into low orbit payload, has a launch mass of about 3,000 tons, which gives the Tsiolkovsky number a value within 30.

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

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

1.Basic concepts

A rocket engine is a jet engine that does not use the environment (air, water) for operation. Chemical rocket engines are the most widely used. Other types of rocket engines are being developed and tested - electric, nuclear and others. The simplest rocket engines running on compressed gases are also widely used on space stations and vehicles. Typically, they use nitrogen as a working fluid. /1/

Classification of propulsion systems

2. Purpose of rocket engines

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

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

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

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

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

3.Thermochemical rocket engines.

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

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

Fuel and oxidizer for liquid jet engines are stored separately in special tanks and supplied to the combustion chamber using pumps. When they are combined in the combustion chamber, temperatures reach 3000 – 4500 °C.

Combustion products, expanding, acquire speeds from 2500 to 4500 m/s. Pushing off from the engine body, they create jet thrust. At the same time, the greater the mass and speed of gas flow, the greater the thrust of the engine.

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

The commonly used liquid rocket engine circuit works as follows. Compressed gas creates the necessary pressure in tanks with cryogenic fuel to prevent the occurrence of gas bubbles in pipelines. Pumps supply fuel to rocket engines. Fuel is injected into the combustion chamber through a large number of injectors. An oxidizer is also injected into the combustion chamber through the nozzles.

In any car, when fuel burns, large heat flows are formed that heat the walls of the engine. If you do not cool the walls of the chamber, it will quickly burn out, no matter what material it is made of. A liquid jet engine is typically cooled by one of the fuel components. For this purpose, the chamber is made of two walls. The cold component of the fuel flows in the gap between the walls.

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

4. Electric rocket engines

Almost all of the rocket engines discussed above develop enormous thrust and are designed to launch spacecraft into orbit around the Earth and accelerate them to cosmic speeds for interplanetary flights. A completely different matter is propulsion systems for spacecraft already launched into orbit or on an interplanetary trajectory. Here, as a rule, you need low-power motors (several kilowatts or even watts) capable of operating for hundreds and thousands of hours and being switched on and off repeatedly. They allow you to maintain flight in orbit or along a given trajectory, compensating for the flight resistance created by the upper layers of the atmosphere and the solar wind. In electric rocket engines, the working fluid is accelerated to a certain speed by heating it with electrical energy. Electricity comes from solar panels or a nuclear power plant. Methods for heating the working fluid are different, but in reality, electric arc is mainly used. It has proven to be very reliable and can withstand a large number of starts. Hydrogen is used as a working fluid in electric arc motors. Using an electric arc, hydrogen is heated to a very high temperature and it turns into plasma - an electrically neutral mixture of positive ions and electrons. The speed of plasma outflow from the engine reaches 20 km/s. When scientists solve the problem of magnetic isolation of plasma from the walls of the engine chamber, then it will be possible to significantly increase the temperature of the plasma and increase the exhaust speed to 100 km/s. The first electric rocket engine was developed in the Soviet Union in the years. under the leadership (later he became the creator of engines for Soviet space rockets and an academician) at the famous Gas Dynamics Laboratory (GDL)./10/

5.Other types of engines

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

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

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

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

6.Nuclear rocket engines

One of the main disadvantages of rocket engines running on liquid fuel is associated with the limited flow rate of gases. In nuclear rocket engines, it seems possible to use the colossal energy released during the decomposition of nuclear “fuel” to heat the working substance. The operating principle of nuclear rocket engines is almost no different from the operating principle of thermochemical engines. The difference is that the working fluid is heated not due to its own chemical energy, but due to “extraneous” energy released during an intranuclear reaction. The working fluid is passed through a nuclear reactor, in which the fission reaction of atomic nuclei (for example, uranium) occurs, and is heated. Nuclear rocket engines eliminate the need for an oxidizer and therefore only one liquid can be used. As a working fluid, it is advisable to use substances that allow the engine to develop great strength traction. This condition is most fully satisfied by hydrogen, followed by ammonia, hydrazine and water. The processes in which nuclear energy is released are divided into radioactive transformations, fission reactions of heavy nuclei, fusion reaction of light nuclei. Radioisotope transformations are realized in so-called isotope energy sources. The specific mass energy (the energy that a substance weighing 1 kg can release) of artificial radioactive isotopes is significantly higher than that of chemical fuels. Thus, for 210Po it is equal to 5*10 8 KJ/kg, while for the most energy-efficient chemical fuel (beryllium with oxygen) this value does not exceed 3*10 4 KJ/kg. Unfortunately, it is not yet rational to use such engines on space launch vehicles. The reason for this is the high cost of the isotopic substance and operational difficulties. After all, the isotope constantly releases energy, even when transported in a special container and when the rocket is parked at the launch site. Nuclear reactors use more energy-efficient fuel. Thus, the specific mass energy of 235U (the fissile isotope of uranium) is equal to 6.75 * 10 9 KJ/kg, that is, approximately an order of magnitude higher than that of the 210Po isotope. These engines can be “turned on” and “off”; nuclear fuel (233U, 235U, 238U, 239Pu) is much cheaper than isotope fuel. Such engines can use not only water as a working fluid, but also more efficient working substances - alcohol, ammonia, liquid hydrogen. The specific thrust of an engine with liquid hydrogen is 900 s. In the simplest design of a nuclear rocket engine with a reactor running on solid nuclear fuel, the working fluid is placed in a tank. The pump supplies it to the engine chamber. Sprayed using nozzles, the working fluid comes into contact with the fuel-generating nuclear fuel, heats up, expands and is thrown out at high speed through the nozzle. Nuclear fuel is superior in energy reserves to any other type of fuel. Then a logical question arises: why do installations using this fuel still have a relatively low specific thrust and a large mass? The fact is that the specific thrust of a solid-phase nuclear rocket engine is limited by the temperature of the fissile material, and the power plant during operation emits strong ionizing radiation, which has a harmful effect on living organisms. Biological protection from such radiation is very important and is not applicable in space. aircraft. Practical development of nuclear rocket engines using solid nuclear fuel began in the mid-50s of the 20th century in the Soviet Union and the USA, almost simultaneously with the construction of the first nuclear power plants. The work was carried out in an atmosphere of increased secrecy, but it is known that such rocket engines have not yet received real use in astronautics. Everything has so far been limited to the use of isotope sources of electricity of relatively low power on unmanned artificial Earth satellites, interplanetary spacecraft and the world famous Soviet “lunar rover”.

7.Nuclear jet engines, operating principles, methods of obtaining impulse in a nuclear propulsion engine.

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

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

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

3. Finally, the impulse is created by the fission products themselves, formed in the process (for example, refractory metals - tungsten, molybdenum) are used to impart special properties to fissile substances.

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

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

8 - Nozzle,

9 - Expanding nozzle nozzle,

10 - Selection of working substance for the turbine,

11 - Power Corps,

12 - Control drum,

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

14 - Drive ring for control drums)

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

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

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

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

10.2 Work on TURE in Russia

American" href="/text/category/amerikanetc/" rel="bookmark">Americans, Russian scientists used the most economical and effective tests of individual fuel elements in research reactors. The entire range of work carried out in the 70-80s allowed the design bureau " Salyut", Design Bureau of Chemical Automatics, IAE, NIKIET and NPO "Luch" (PNITI) to develop various projects of space nuclear propulsion engines and hybrid nuclear power plants. In the Design Bureau of Chemical Automatics under the scientific leadership of NIITP (FEI, IAE, NIKIET, NIITVEL, NPO were responsible for the reactor elements). Luch", MAI) were created YARD RD 0411 and nuclear engine of minimum size RD 0410 thrust 40 and 3.6 tons, respectively.

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

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

Currently, such work at the site has been stopped, although the equipment is maintained in relatively working condition. The test bench base of NPO Luch is the only experimental complex in the world where it is possible to test elements of nuclear propulsion reactors without significant financial and time costs. It is possible that the resumption in the United States of work on nuclear propulsion engines for flights to the Moon and Mars within the framework of the Space Research Initiative program with the planned participation of specialists from Russia and Kazakhstan will lead to the resumption of activity at the Semipalatinsk base and the implementation of a “Martian” expedition in the 2020s .

Main Features

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

· Outflow velocity of the working fluid (hydrogen): 9100 - 9800 m/sec.

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

· Maximum operating temperatures: 3000°С - 3700°С (short-term switching on).

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

11.Device

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

1 - line from the working fluid tank

2 - turbopump unit

3 - control drum drive

4 - radiation protection

5 - regulating drum

6 - retarder

7 - fuel assembly

8 - reactor vessel

9 - fire bottom

10 - nozzle cooling line

11- nozzle chamber

12 - nozzle

12.Operating principle

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

Nuclear rocket engine reactor

MsoNormalTable">

Working fluid

Density, g/cm3

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

0.071 (liquid)

0.682 (liquid)

1,000 (liquid)

No. Dann

No. Dann

No. Dann

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

15.Benefits

The main advantage of TNREs over chemical rocket engines is the achievement of a higher specific impulse, significant energy reserves, compactness of the system and the ability to obtain very high thrust (tens, hundreds and thousands of tons in a vacuum. In general, the specific impulse achieved in a vacuum is greater than that of spent two-component chemical rocket fuel (kerosene-oxygen, hydrogen-oxygen) by 3-4 times, and when operating at the highest thermal intensity by 4-5 times. Currently, in the USA and Russia there is significant experience in the development and construction of such engines, and if necessary (special programs). space exploration) such engines can be produced in a short time and will have a reasonable cost in the case of using TURD for accelerating spacecraft in space, and subject to the additional use of perturbation maneuvers using the gravitational field. major planets(Jupiter, Uranus, Saturn, Neptune) the achievable boundaries of studying the solar system are significantly expanding, and the time required to reach distant planets is significantly reduced. In addition, TNREs can be successfully used for devices operating in low orbits of giant planets using their rarefied atmosphere as a working fluid, or for operating in their atmosphere. /8/

16.Disadvantages

The main disadvantage of TNRE is the presence of a powerful flow of penetrating radiation (gamma radiation, neutrons), as well as the removal of highly radioactive uranium compounds, refractory compounds with induced radiation, and radioactive gases with the working fluid. In this regard, TURE is unacceptable for ground launches in order to avoid deterioration of the environmental situation at the launch site and in the atmosphere. /14/

17.Improving the characteristics of TURD. Hybrid turboprop engines

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

18. Radiation hazard from nuclear propulsion engines.

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

Currently the problem radiation protection spacecraft with nuclear propulsion engines is considered solved in principle. Fundamental issues related to the maintenance of nuclear propulsion engines at test stands and launch sites have also been resolved. Although an operating NRE poses a danger to operating personnel, already one day after the end of operation of the NRE, one can, without any personal protective equipment, stand for several tens of minutes at a distance of 50 m from the NRE and even approach it. The simplest means of protection allow operating personnel to enter the work area YARD shortly after the tests.

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

Conclusion

When considering the prospects for the development and use of nuclear propulsion engines in astronautics, one should proceed from the achieved and expected characteristics various types Nuclear propulsion engines, from what their application can give to astronautics and, finally, from the presence of a close connection between the problem of nuclear propulsion and the problem of energy supply in space and with issues of energy development in general.

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

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

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

The advantages of solid-phase and other nuclear propulsion engines with fission reactors are most fully revealed in the study of such complex space programs as manned flights to the planets of the Solar System (for example, during an expedition to Mars). In this case, an increase in the specific impulse of the thruster makes it possible to solve qualitatively new problems. All these problems are greatly alleviated when using a solid-phase nuclear-propellant rocket engine with a specific impulse twice as high as that of modern liquid-propellant rocket engines. In this case, it also becomes possible to significantly reduce flight times.

It is most likely that in the near future solid-phase nuclear propulsion engines will become one of the most common rocket engines. Solid-phase nuclear propulsion engines can be used as devices for long-distance flights, for example, to planets such as Neptune, Pluto, and even fly beyond Solar System. However, for flights to the stars, a nuclear powered engine based on fission principles is not suitable. In this case, promising are nuclear engines or, more precisely, thermonuclear jet engines (TRE), operating on the principle of fusion reactions, and photonic jet engines (PRE), the source of momentum in which is the annihilation reaction of matter and antimatter. However, most likely humanity will use a different method of transportation to travel in interstellar space, different from jet.

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

LITERATURE

Sources:

1. "Rockets and People. Book 4 Moon Race" - M: Znanie, 1999.
2. http://www. lpre. de/energomash/index. htm
3. Pervushin “Battle for the Stars. Cosmic Confrontation” - M: knowledge, 1998.
4. L. Gilberg “Conquest of the sky” - M: Znanie, 1994.
5. http://epizodsspace. *****/bibl/molodtsov
6. “Engine”, “Nuclear engines for spacecraft”, No. 5 1999

7. "Engine", "Gas-phase nuclear engines for spacecraft",

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

M.: Knowledge, 1983.

11. , Chekalin space exploration. - M.:

Knowledge, 1988.

12. Gubanov B. “Energy - Buran” - a step into the future // Science and life.-

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

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

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

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

APPLICATION

Main characteristics of solid-phase nuclear jet engines

Country of origin	Engine	Thrust in vacuum, kN	Specific impulse, sec		Project work, year
	NERVA/Lox Mixed Cycle

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

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

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

Over the past half century, this rocket technology has been perfected all over the world to the smallest detail. But the rocket scientists themselves admit that . Improvement - yes, it is necessary. Trying to increase the payload of rockets from the current 23 tons to 100 and even 150 tons based on “improved” combustion engines - yes, you need to try. But this is a dead end from an evolutionary point of view. " No matter how much rocket engine specialists around the world work, the maximum effect we get will be calculated in fractions of a percent. Roughly speaking, everything has been squeezed out of existing rocket engines, be they liquid or solid propellant, and attempts to increase thrust and specific impulse are simply futile. Nuclear power propulsion systems provide a multifold increase. Using the example of a flight to Mars, now it takes one and a half to two years to fly there and back, but it will be possible to fly in two to four months "- the former head of the Russian Federal Space Agency assessed the situation at one time Anatoly Perminov.

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

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

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

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

« In the 90s of the 20th century, we at the Keldysh Center resumed work on ion engines. Now a new cooperation must be created for such a powerful project. There is already a prototype of an ion engine on which basic technological and design solutions can be tested. But standard products still need to be created. We have a set deadline - by 2018 the product should be ready for flight tests, and by 2015 the main engine testing should be completed. Next - life tests and tests of the entire unit as a whole.“, noted last year the head of the electrophysics department of the Research Center named after M.V. Keldysh, Professor, Faculty of Aerophysics and Space Research, MIPT Oleg Gorshkov.

What is the practical benefit for Russia from these developments? This benefit far exceeds the 17 billion rubles that the state intends to spend by 2018 on creating a launch vehicle with a nuclear power plant on board with a capacity of 1 MW. Firstly, this is a dramatic expansion of the capabilities of our country and humanity in general. A nuclear-powered spacecraft provides real opportunities for people to accomplish things on other planets. Now many countries have such ships. They also resumed in the United States in 2003, after the Americans received two samples of Russian satellites with nuclear power plants.

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

Secondly, such ships make it possible to sharply intensify activity in near-Earth space and provide a real opportunity to begin the colonization of the Moon (there are already projects for the construction of nuclear power plants on the Earth’s satellite). " The use of nuclear propulsion systems is being considered for large manned systems, rather than for small spacecraft, which can fly on other types of installations using ion engines or solar wind energy. Nuclear propulsion systems with ion engines can be used on an interorbital reusable tug. For example, transport cargo between low and high orbits, and fly to asteroids. You can create a reusable lunar tug or send an expedition to Mars“, says Professor Oleg Gorshkov. Ships like these are dramatically changing the economics of space exploration. According to calculations by RSC Energia specialists, a nuclear-powered launch vehicle reduces the cost of launching a payload into lunar orbit by more than half compared to liquid rocket engines.

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