The political, press and web debate about the fate of Russian ICBMs is incredibly intense. With reinforced concrete arguments and a consciousness of their own righteousness, the sides defend who is "Bulava", who is "Sineva", who is liquid-propellant missiles, who is solid-propellant. In this article, without delving into the debate of the parties, we will try to decompose the entire knot of problems into more or less understandable component parts.
The dispute, of course, is about the future of Russia's strategic nuclear forces, in which many, not without reason, tend to see the main guarantee of the state sovereignty of our country. The main problem that exists today is the gradual retirement of old Soviet ICBMs, which could carry several warheads at once. This applies to missiles R-20 (ten warheads) and UR-100H (six warheads). They are being replaced by the mine-based and mobile-based Topol-M solid-propellant (one warhead per missile) and the RS-24 Yars (three warheads). If we take into account that new missiles are entering service rather slowly (only six Yarsov were put into service), the future is not very bright: the Strategic Missile Forces in deployed form will have fewer and fewer carriers and especially warheads. The current START-3 treaty gives Russia the right to have up to 700 deployed and 100 non-deployed carriers and up to 1,550 deployed warheads, but with the current state of affairs there are great doubts that after the decommissioning of all old missile technology, such indicators for our country will be achievable even taking into account the sea and the aviation components of the nuclear triad. Where to get so many new missiles?
Relevance of choice
The topic of comparative advantages and disadvantages of liquid-propellant and solid-propellant rocket engines is also highly debated, and there are two reasons for this. The first is the future of Russian SLBMs and, in general, the naval component of the nuclear triad. All the SLBMs currently in service were developed at the Makeev SRC (Miass), and all of them are built according to the liquid scheme. In 1986, the Makeyevites began work on the Bark solid-propellant SLBM for the Borey 955 SSBN. However, in 1998, after an unsuccessful launch, the project was closed, and the topic of a solid-propellant sea rocket was transferred to the Moscow Institute of Heat Engineering, as it was said, to unify the product with the Topol-M. Topol-M is the brainchild of MIT, and this company had experience in creating solid-propellant missiles. But what MIT did not have was the experience in designing SLBMs. The decision to transfer the maritime theme to the land-based design bureau still causes bewilderment and controversy among the military-industrial complex, and, of course, everything that happens around the Bulava does not leave indifferent the representatives of the Makeev SRC. Makeyevtsy continued successful launches of their "Sineva" (R-29RMU2), built, of course, on a liquid-propellant engine, and the solid-propellant "Bulava" only this summer carried out the first and successful launch from the board of a standard SSBN of the 955th project. As a result, the situation looks something like this: Russia has a reliable liquid-propellant SLBM Sineva, but no one else is going to build Project 667BDRM submarines for it. On the contrary, for the lighter Bulava, which barely showed signs of stable operation, one RPK SN Borey (Yuri Dolgoruky) has already been built, and seven more submarine cruisers of this class will appear in the next six years. Intrigues were added by the May launch of a new Makeyevka development - the Liner SLBM, which, according to unofficial information, is a modification of the Sineva with a modified warhead and is now capable of accommodating about ten low-yield warheads. The Liner was launched from the K-84 Yekaterinburg SSBN - and this is a submarine of the same project 667BDRM, on which Sineva is based.
Nostalgia for "Satan"
There is one more reason why the topic of “liquid propellant engines versus solid propellant rocket engines” has become the focus of attention. This year, the General Staff and a number of representatives of the military-industrial complex made semi-official statements of their intention to create a new heavy ground-based rocket based on liquid-propellant rocket engines by 2018 - obviously, based on the developments of the Makeev SRC. The new carrier will become a classmate of the RS-20 complex, which is gradually disappearing into history, nicknamed "Satan" in the West. A heavy missile with a multiple warhead will be able to receive a significant number of warheads, which would help to cope with a likely shortage of launch vehicles for nuclear weapons in the future. In unison with the General Staff, the honorary general designer of NPO Mashinostroyenia Herbert Efremov spoke on the pages of the press. He proposed to restore cooperation with the Dnepropetrovsk design bureau "Yuzhnoye" (Ukraine) and "repeat" both stages of the R-20 (R-362M) at their production facilities. On this time-tested heavy foundation, Russian designers could put new warheads and a new control system. Thus, both land-based and naval Russian ballistic missiles on solid propellants have a promising liquid-propellant alternative, even if in one case it is real, and in the other it is very hypothetical.
Solid rocket motor: line of defense
The relative advantages and disadvantages of liquid-propellant rocket engines and solid propellants are well known. A liquid-propellant engine is more difficult to manufacture, it includes moving parts (pumps, turbines), but it is easy to control the fuel supply, control and maneuvering tasks are facilitated. A solid-propellant rocket is structurally much simpler (in fact, a fuel stick burns in it), but it is also much more difficult to control this combustion. The required thrust parameters are achieved by varying the chemical composition of the fuel and the geometry of the combustion chamber. In addition, the manufacture of a fuel charge requires special control: air bubbles and foreign inclusions must not penetrate into the charge, otherwise the combustion will become uneven, which will affect the thrust. However, for both schemes, nothing is impossible, and none of the shortcomings of solid propellant rocket engines prevented the Americans from making all their strategic missiles using a solid-propellant scheme. In our country, the question is posed somewhat differently: are our technologies for creating solid-fuel missiles advanced enough to solve the military-political problems facing the country, or is it better to turn to the old proven liquid-fuel schemes for this purpose, behind which we have a tradition of decades?
Supporters of heavier liquid-propellant missiles consider the main disadvantage of domestic solid-fuel projects to be a low throw weight. The Bulava is also being challenged for the range, the parameters of which are approximately at the level of the Trident I, that is, the American SLBM of the previous generation. To this management, MIT replies that the lightness and compactness of the Bulava have their advantages. In particular, the missile is more resistant to the damaging factors of a nuclear explosion and to the effects of laser weapons, it has an advantage over a heavy missile in breaking through the missile defense of a potential enemy. The decrease in the cast mass can be compensated for by more accurate targeting. As for the range, it is enough to reach the main centers of any possible opponents, even if you shoot from the pier. Of course, if a target is too far away, the SSBN can get close to it. The defenders of solid-propellant missiles place special emphasis on a lower trajectory of their flight and on better dynamics, which makes it possible to reduce the active section of the trajectory several times in comparison with rockets based on liquid-propellant rocket engines. Reducing the active area, that is, the part of the trajectory along which the ballistic missile flies with the cruise engines turned on, is considered important from the point of view of achieving greater invisibility for missile defense systems. If we allow the appearance of space-based strike missile defense systems, which is still prohibited by international treaties, but may one day become a reality, then, of course, the higher the ballistic missile rises upward with a blazing torch, the more vulnerable it will be. Another argument of the proponents of rockets with solid propellants is, of course, the use of a "sweet couple" - asymmetric dimethylhydrazine as a fuel and dinitrogen tetroxide as an oxidizing agent (heptyl-amyl). And although incidents with solid fuel also happen: for example, at the Votkinsk plant, where Russian missiles are made on solid propellants, an engine exploded in 2004, the consequences of a highly toxic heptyl spill, say, on a submarine can be disastrous for the entire crew.
Agility and invulnerability
What do the adherents of the liquid fuel tradition say in response to this? The most characteristic objection belongs to Herbert Efremov in his correspondence polemic with the leadership of MIT. From his point of view, the difference in the active area between rockets with liquid propellant engines and solid propellant rocket engines is not so great and is not so important when passing missile defense in comparison with much higher maneuverability. With a developed missile defense system, it will be necessary to significantly accelerate the distribution of warheads to targets using the so-called bus - a special stage of disengagement, which, each time changing direction, sets the direction of the next warhead. Opponents from MIT are inclined to abandon the "bus", believing that the heads should be able to maneuver and aim at the target on their own.
Critics of the idea of reviving heavy liquid-propellant missiles point to the fact that the likely successor to Satan will certainly be a silo-based missile. The coordinates of the mines are known to the probable enemy, and in the event of an attempt to deliver a so-called disarming strike, the missile deployment sites will undoubtedly be among the priority targets. However, it is not so easy to get into the mine, and it is even more difficult to destroy it, despite the fact that, for example, mobile complexes "Topol-M", slow-moving and moving in open areas in a strictly defined area, are much more vulnerable.
The problem of poisonous heptyl is now being solved by the amputation of missile tanks. Heptyl, for all its fantastic toxicity, is a fuel with a unique energy density. In addition, it is very cheap, because it is obtained as a by-product in chemical production, which makes the "liquid" project more attractive from the economic point of view (as already mentioned, solid fuel is very demanding in the technological process, and therefore very expensive). Despite some demonization of NDMH (heptyl), which in the public consciousness is associated exclusively with military projects and possible environmental disasters, this fuel is used for quite peaceful purposes when launching heavy Proton and Dnepr missiles, and they have long learned to work with it quite safely. how to work with many other substances used in the industry. Only the recent accident over Altai of the cargo "Progress", carrying a cargo of heptyl and amyl to the ISS, once again slightly spoiled the reputation of asymmetric dimethylhydrazine.
On the other hand, it is unlikely that the fuel price is of fundamental importance in the operation of ICBMs, after all, ballistic missiles fly extremely rarely. Another question is how much the possible creation of a heavy launch vehicle will cost, given that the Bulava has already absorbed many billions. Obviously, cooperation with Ukraine is the last thing our authorities and the military-industrial complex will go to, because no one will abandon such a serious matter to the mercy of a volatile political course.
The question of the future constituents of Russian strategic nuclear forces is too close to politics to remain a purely technical issue. Behind the comparison of concepts and schemes, behind the polemics in the government and in society, of course, there is not only a comparison of rational considerations, but also conflicts of interests and ambitions. Everyone, of course, has their own truth, but we would like the public interest to prevail in the end. And how it will be provided technically, let the experts decide.
