Russia has developed strategic nuclear forces, the main component of which is intercontinental ballistic missiles of various types used in stationary or mobile ground complexes, as well as on submarines. With a certain similarity at the level of basic ideas and solutions, products of this class have noticeable differences. In particular, rocket engines of various types and classes are used, corresponding to one or another customer's requirements.
From the point of view of the features of the power plants, all obsolete, relevant and promising ICBMs can be divided into two main classes. Such weapons can be equipped with liquid propellant rocket engines (LPRE) or solid fuel engines (solid propellant rocket engines). Both classes have their own advantages, thanks to which they find application in various projects, and so far none of them has been able to oust a "competitor" from its field. The issue of power plants is of great interest and is worth separate consideration.
History and theory
It is known that the first rockets, which appeared many centuries ago, were equipped with solid-propellant engines using the simplest fuel. Such a power plant retained its position until the last century, when the first liquid fuel systems were created. In the future, the development of the two classes of engines proceeded in parallel, although liquid-propellant rocket engines or solid propellants from time to time replaced each other as industry leaders.
Launch of the UR-100N UTTH rocket with a liquid engine. Photo Rbase.new-factoria.ru
The first long-range missiles, the development of which led to the emergence of intercontinental complexes, were equipped with liquid engines. In the middle of the last century, it was liquid rocket engines that made it possible to obtain the desired characteristics using available materials and technologies. Later, experts from leading countries began to develop new grades of ballistic propellants and mixed propellants, which resulted in the emergence of solid propellants suitable for use on ICBMs.
To date, both liquid-propellant and solid-propellant missiles have become widespread in the strategic nuclear forces of different countries. It is curious that Russian ICBMs are equipped with power plants of both classes, while the United States abandoned liquid-propellant engines several decades ago in favor of solid-fuel ones. Despite this difference in approaches, both countries managed to build missile groups of the desired appearance with the required capabilities.
In the field of intercontinental missiles, liquid-propellant engines were the first. Such products have a number of advantages. Liquid fuel allows a higher specific impulse to be obtained, and the design of the engine allows the thrust to be changed in relatively simple ways. Most of the volume of a rocket with a liquid propellant engine is occupied by fuel and oxidizer tanks, which in a certain way reduces the requirements for the strength of the hull and simplifies its production.
At the same time, liquid-propellant rocket engines and missiles equipped with them are not without drawbacks. First of all, such an engine is distinguished by the highest complexity of production and operation, which negatively affects the cost of the product. ICBMs of the first models had a drawback in the form of the complexity of preparation for launch. Refueling of fuel and oxidizer was carried out immediately before the start, and in addition, in some cases, it was associated with some risks. All this negatively affected the combat qualities of the missile system.
R-36M liquid-propellant missiles in transport and launch containers. Photo Rbase.new-factoria.ru
The solid fuel rocket engine and the rocket built on its basis have positive aspects and advantages over the liquid system. The main plus is the lower production cost and simplified design. Also, solid propellants have no risks of aggressive fuel leaks, and in addition, they are distinguished by the possibility of longer storage. During the active phase of an ICBM flight, a solid-propellant engine provides better acceleration dynamics, reducing the likelihood of a successful interception.
A solid-propellant engine loses out to a liquid one in its specific impulse. Since the combustion of a solid fuel charge is almost uncontrollable, engine thrust control, stopping or restarting require special technical means that are complex. The solid propellant rocket body performs the functions of a combustion chamber and therefore must have appropriate strength, which makes special requirements for the units used, and also negatively affects the complexity and cost of production.
Rocket engine, solid propellant engine and strategic nuclear forces
Currently, the strategic nuclear forces of Russia are armed with about a dozen ICBMs of different classes, designed to solve urgent combat missions. The Strategic Missile Forces (Strategic Missile Forces) operate five types of missiles and are awaiting the appearance of two more new complexes. The same number of missile systems are used on naval submarines, but fundamentally new missiles have not yet been developed in the interests of the naval component of the "nuclear triad".
Despite their considerable age, the UR-100N UTTH and R-36M / M2 missiles still remain in the troops. Such ICBMs of the heavy class include several stages with their own liquid-propellant engines. With a large mass (more than 100 tons for the UR-100N UTTKh and about 200 tons for the R-36M / M2), two types of missiles carry a significant fuel supply, which ensures the dispatch of a heavy warhead to a range of at least 10 thousand km.
General view of the RS-28 "Sarmat" rocket. Drawing "State Missile Center" / makeyev.ru
Since the end of the fifties, in our country, the problem of using solid propellants on promising ICBMs has been studied. The first real results in this area were obtained by the early seventies. In recent decades, this direction has received a new impetus, thanks to which a whole family of solid-propellant missiles has appeared, representing the consistent development of general ideas and solutions based on modern technologies.
At present, the Strategic Missile Forces has the RT-2PM Topol, RT-2PM2 Topol-M and RS-24 Yars missiles. At the same time, all such missiles are operated with both mine and mobile ground launchers. Rockets of three types, created on the basis of general ideas, are built according to a three-stage scheme and are equipped with solid-propellant engines. Having fulfilled the customer's requirements, the authors of the projects managed to minimize the dimensions and weight of the finished missiles.
The missiles of the RT-2PM, RT-2PM2 and RS-24 complexes have a length of no more than 22.5-23 m with a maximum diameter of less than 2 m. 1-1, 5 tons. The Topol missiles are equipped with a monoblock warhead, while Yars, according to known data, carries several separate warheads. The flight range is at least 12 thousand km.
It is easy to see that with the basic flight characteristics at the level of older liquid-propellant missiles, the solid-propellant Topoli and Yars are distinguished by their smaller dimensions and launch weight. However, with all this, they carry less payload.
Topol mobile soil complex. Photo of the Ministry of Defense of the Russian Federation
In the future, the Strategic Missile Forces should receive several new missile systems. Thus, the RS-26 Rubezh project, which was created as an option for the further development of the Yars system, again provides for the use of a multistage scheme with solid propellants at all stages. Earlier there was information according to which the "Rubezh" system is intended to replace the aging RT-2PM "Topol" complexes, which affected the main features of its architecture. In terms of the main technical characteristics, the "Rubezh" should not differ significantly from the "Topol", although it is possible to use a different payload.
Another promising development is the RS-28 Sarmat heavy ICBM. According to official data, this project provides for the creation of a three-stage rocket with liquid propellants. It was reported that the Sarmat missile will have a length of about 30 meters with a launch weight of over 100 tons. It will be able to carry “traditional” special warheads or a new type of hypersonic strike system. Due to the use of liquid-propellant rocket engines with sufficient characteristics, it is expected to obtain the maximum flight range at the level of 15-16 thousand km.
The Navy has at its disposal several types of ICBMs with different characteristics and capabilities. The core of the naval component of the strategic nuclear forces is currently the ballistic missiles of submarines of the R-29RM family: the R-29RM itself, the R-29RMU1, the R-29RMU2 "Sineva" and the R-29RMU2.1 "Liner". In addition, the newest R-30 Bulava missile entered the arsenals a few years ago. As far as is known, now the Russian industry is developing several projects for the modernization of missiles for submarines, but there is no talk about the creation of fundamentally new complexes.
In the field of domestic ICBMs for submarines, there are trends reminiscent of the development of "land" complexes. Older R-29RM products and all options for their modernization have three stages and are equipped with several liquid engines. With the help of such a power plant, the R-29RM missile is capable of delivering four or ten warheads of different power with a total mass of 2, 8 tons at a range of at least 8,300 km. The modernization project for the R-29MR2 Sineva provided for the use of new navigation and control systems. Depending on the available combat load, a rocket with a length of 14.8 m and a mass of 40.3 tons is capable of flying at a range of up to 11.5 thousand km.
Loading a Topol-M missile into a silo launcher. Photo of the Ministry of Defense of the Russian Federation
The newer project of the R-30 Bulava submarine missile, on the contrary, provided for the use of solid-propellant engines at all three stages. Among other things, this made it possible to reduce the length of the rocket to 12.1 m and reduce the launch weight to 36.8 tons. At the same time, the product carries a combat load weighing 1, 15 tons and delivers it to a range of 8-9 thousand km. Not so long ago, it was announced the development of a new modification of the Bulava, which has different dimensions and increased weight, due to which it will be possible to increase the combat load.
Development trends
It is well known that in recent decades the Russian command has relied on the development of promising solid-propellant missiles. The result of this was the consistent appearance of the Topol and Topol-M complexes, and then Yars and Rubezh, whose missiles are equipped with solid propellants. LRE, in turn, remain only on relatively old "land" missiles, the operation of which is already coming to an end.
However, a complete abandonment of liquid-propellant ICBMs is not yet planned. As a replacement for the existing UR-100N UTTKh and R-36M / M2, a new product RS-28 "Sarmat" with a similar power plant is being created. Thus, liquid-propellant engines in the foreseeable future will be used only on heavy-class missiles, while other complexes will be equipped with solid-propellant systems.
The situation with submarine ballistic missiles looks similar, but has some differences. A significant number of liquid-propellant missiles also remain in this area, but the only new project involves the use of solid propellants. The further development of the event can be predicted by examining the existing plans of the military department: the program for the development of the submarine fleet clearly indicates which missiles have a great future, and which will be decommissioned over time.
Self-propelled launcher RS-24 "Yars". Photo Vitalykuzmin.net
Older R-29RM missiles and their latest modifications are intended for nuclear submarines of projects 667BDR and 667BDRM, while R-30 was developed for use on the latest missile carriers of Project 955. Ships of the 667 family are gradually depleting their resource and will eventually be decommissioned due to the complete moral and physical obsolescence. Together with them, accordingly, the fleet will have to abandon missiles of the R-29RM family, which will simply remain without carriers.
The first missile submarine cruisers of Project 955 "Borey" have already been accepted into the combat strength of the Navy, and in addition, the construction of new submarines continues. This means that in the foreseeable future the fleet will receive a significant grouping of Bulava missile carriers. Service "Boreyev" will continue for several decades, and therefore the R-30 missiles will remain in service. It is possible to create new modifications of such weapons, capable of supplementing and then replacing ICBMs of the basic version. One way or another, products of the R-30 family will eventually replace the aging R-29RM missiles as the basis of the naval component of the strategic nuclear forces.
Advantages and disadvantages
Different classes of rocket engines used on modern strategic missiles have their own pros and cons of one kind or another. Liquid and solid fuel systems surpass each other in some parameters, but lose in others. As a result, customers and designers have to choose the type of power plant in accordance with their requirements.
Conventional liquid-propellant engine differs from solid propellant rocket engine in higher specific impulse rates and other advantages, which allows increasing the payload. At the same time, the corresponding supply of liquid fuel and oxidizer leads to an increase in the dimensions and weight of the product. Thus, a liquid-propellant rocket turns out to be the optimal solution in the context of the deployment of a large number of silo launchers. In practice, this means that at present a significant part of the launch silos is occupied by the R-36M / M2 and UR-100N UTTH missiles, and in the future they will be replaced by the promising RS-28 "Sarmat".
Rockets of the Topol, Topol-M and Yars types are used both with mine installations and as part of mobile ground systems. The latter possibility is provided, first of all, by the low launch weight of the missiles. A product weighing no more than 50 tons can be placed on a special multi-axle chassis, which cannot be done with existing or hypothetical liquid-propellant missiles. The new RS-26 Rubezh complex, considered as a replacement for the Topol, is also based on similar ideas.
Submarine missile R-29RM. Drawing "State Missile Center" / makeyev.ru
The characteristic feature of rockets with solid propellants in the form of reduction in size and weight also matters in the context of naval armaments. The submarine missile must be of minimum dimensions. The ratio of the dimensions and flight characteristics of the R-29RM and R-30 missiles shows exactly how such advantages can be used in practice. So, unlike their predecessors, the newest Project 955 nuclear submarines do not need a large superstructure covering the upper part of the launchers.
However, the reduction in weight and dimensions comes at a price. Lighter solid-propellant missiles differ from other domestic ICBMs in a lower combat load. In addition, the specificity of solid propellant rocket motors leads to a lower weight perfection in comparison with liquid-propellant rockets. However, in all likelihood, such problems are being solved by creating more effective combat units and control systems.
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Despite lengthy research and development work, as well as a lot of controversy, the conditional confrontation between liquid and solid propellant engines has not yet ended with an unconditional victory of one of the "competitors". On the contrary, the Russian military and engineers came to a balanced conclusion. Engines of different types are used in those areas where they can show the best results. Thus, light missiles for land mobile complexes and submarines receive solid propellants, while heavy missiles with a silo launch, both now and in the future, should be equipped with liquid propellants.
In the current situation, taking into account the existing opportunities and prospects, such an approach looks the most logical and successful. In practice, it allows you to get maximum results with a noticeable reduction in the influence of negative factors. It is quite possible that such an ideology will persist in the future, including with the use of promising technologies. This means that in the near and distant future, Russian strategic nuclear forces will be able to receive modern intercontinental ballistic missiles with the highest possible characteristics and combat qualities that directly affect the effectiveness of deterrence and the country's security.
