Why did Russia opt for liquid-fuel in its next generation ICBMs?

By Dr Igor Sutyagin for RUSI.org

There are strong indications that Russia has made the decision to develop a new-generation intercontinental ballistic missile (ICBM): on 12 May, the contractor for the missile's preliminary design was announced. The Russian Ministry of Defense has decided that the Makeev State Rocket Centre (Makeev SRC) will lead the research aimed to deploy the fifth generation Intercontinental Ballistic Missiles (ICBM) by 2018. The Russian Federation is wiling to invest in its rocket industry by 2020 up to £1.62 billion, to modernise ICBM production capacities and increase output two-fold during that period.

The most intriguing feature of the decision is that it calls for a liquid-fuel missile. While liquid-fuel rockets have higher (as compared to solid-fuel ones) launch-weight to throw-weight ratio, they are also characterised by more durable boost-phase which makes them easier targets to interception than high-acceleration solid-fuel missiles. So, how can one explain this seemingly extravagant Russian decision?

Maintaining the credibility of Russia's nuclear arsenal

A mighty deterrence force is seen in Moscow as one of a few real attributes of great power status remaining in the Russian leadership's possession. The maintenance of strategic nuclear capabilities befitting a superpower therefore meets a psychological, as well as military objective. More importantly, the credibility of Russia's nuclear arsenal - and its potential equality with that of the US - remains one of the Kremlin's key political aims. And what worries Russia most is the possibility - however theoretical - that the US could destroy the Russian nuclear arsenal without Moscow retaining a credible capability for retaliation. If this possibility is remotely feasible, the Americans will no longer have any interest in treating Russia seriously. And that represents the Kremlin's biggest fear.

There are three paths which may lead to this outcome. The deployment of an ABM system(s) capable of intercepting the largest share of the missiles or warheads of the Russian retaliatory strike may result in Russia losing its status. A second possibility of Russia's arsenal becoming irrelevant is the dramatic numerical inferiority of Russia's strategic forces under the Strategic Offensive Reductions Treaty (SORT), since Russia will be unable to keep up with even the ceilings which SORT would allow it in order to maintain a credible deterrence.

Finally, the large-scale US and West European ABM deployment represents the third and the most serious eventuality for Russia's nuclear deterrent to become irrelevant.

To counterbalance these threats Russia needs to keep up to the higher SORT ceilings and to ensure that its nuclear forces survive against any ABM systems.  Undoubtedly, Russia has problems fulfilling that task.

'Parallel Separation' warheads

The country's current geo-political situation renders the Russian strategic nuclear triad effectively the dyad against the United States: hence the Russian military planners have to rely on mainly ballistic missile forces. Seen from this perspective, it would be highly desirable to deploy the 'parallel separation' warheads (thus providing a dramatically reduced time available for mid-course intercept) on a substantial portion of strategic missiles. That would improve the Russian forces' capabilities to penetrate mid-course and terminal defences, and something of this kind is being planned now. However, 'parallel separation' warheads are much heavier than the 'traditional' ones, and therefore there is a requirement to either to reduce the number of warheads per missile (which contradicts current Russian intentions) or utilise boosters with greater payload. A heavy liquid-fuel missile could be an attractive option to solve this dilemma, mainly because solid-fuel missiles do not promise that straight-forward and effective solution as liquid-fuel ones do.

Russia had already been forced to reduce the original solid-fuel ICBMs/SLBMs production plans to less than one half of the intended capacity for ICBMs and by one third for SLBMs, regardless of the fact that the plans complied with SORT ceilings.  Such a decision was inevitable: there are fifty critically important materials required for the Russian solid-fuel rockets production technology which are currently absent in the country. Hence, the Russian leadership is already beset by problems in finding ways to increase strategic forces levels - both in terms of delivery means and the deployed state-of-the-art warheads - and the prospect of not being able to deploy the necessary force level remains quite serious.

Nevertheless even the ultimate resolution of Russia's difficulties with the critical materials supply would not resolve all the problems associated with solid-fuel missiles. There is just ONE designer and producer of solid-fuel strategic missiles in Russia now - the Moscow Institute for Thermal Techniques (MITT) with Votkinsk Plant as its 'business end'. The concentration of all the design and production tasks within just one company clearly needs to be avoided, if only in order to prevent a possible catastrophic failure of designs. And the only Russian design organisation able to compete with the MITT - the Makeev SRC - is mainly specialised in design of liquid-fuel missiles.

In summary, to ensure the credibility of the country's strategic deterrence, Russian leaders need to solve three interrelated challenges:

a) to prevent a catastrophic failure of the current and prospective strategic weapons delivery designs;

b) to provide the desirable amount of strategic nuclear weapons delivery platforms with the required capabilities (including 'parallel separation' warheads); and

c) to guarantee an equality with the US in deployed strategic warheads.

A necessary decision?

A feasible way to address all the three parts of the problem would be to deploy a new high throw-weight (i.e., heavy enough) ICBM which must be non-MITT designed and non-Votkinsk produced. In the current Russian conditions, such a missile can only be liquid-fuel. Seen from this perspective, the decision to proceed with a liquid-fuel 'conditionally heavy' ICBM is neither unexpected nor extravagant.

Meanwhile the Russian Ministry of Defence's latest decision brings with it at least one political implication of huge importance: Russian suspicions about the global deployment of the US ABM system are going to continue and gain momentum. The decision on a new liquid-fuel ICBM can solve many difficulties, but one problem remains: the Russian forces' vulnerability against a boost-phase intercept. And the more Russia will rely on liquid-fuel missiles, the stronger the Russian leaders' concerns about the deterrence potential's credibility will be. In short, this is the start of a vicious circle.

 

The views expressed in this article are the author's own and do not necessarily reflect those of RUSI.