At the end of 2013 Russian completed converting one of silo based missile divisions from the Cold War era RS-18 (SS-19) to the new RS-24 “Yars”. A Russian ICBM division has three regiments each with three battalions and each battalion has three ICBMs. Russia believes Yars is a worthy successor to the vernerable, reliable and aging RS-18s. Reinforcing that attitude was another successful test of an RS-24 on December 24th. Russia began deploying RS-24s in 2010. The latest move, to replace RS-18s with RS-24s indicates a high degree of confidence in the RS-24 and enough cash to retire the RS-18s and build RS-24s to replace them.
The 106 ton RS-18 is a 24.5 meter (76 foot) long missile that uses storable liquid fuel, meaning that the missile is inherently more complex than a solid fuel missile. The RS-18 entered service in 1975, and it wasn't until the 1980s that Russia began producing reliable solid fuel rocket motors large enough for ICBMs (the 45 ton RS-12M). The last RS-18s were manufactured in 1990 and Russia expects each RS-18 to last 30 years if well maintained, regularly refurbished and needed badly enough. The RS-18 was developed as a "light" ICBM, in effect, a competitor for the U.S. Minuteman series. The RS-18 was the first Russian ICBM to carry MIRV (multiple independently targeted reentry vehicles). The RS-18 carries six warheads and has a range of 10,000 kilometers. Topol-M/Tars has a range of 11,000 kilometers. Russia is also extending the life of its heavier (217 ton) RS-20 ICBMs to 30 years. This missile carries ten warheads and is also being converted to launch satellites. Eventually Yars will probably replace this one as well.
In 2009 Russia announced that the latest version of the Topol series, the RS-24 (Yars), had entered service. The RS-24 appears to be a slightly heavier version of the 46 ton Topol-M (or RS-12M1/M2). The RS-24 is being deployed in silos as well as on wheeled vehicles. The RS-24 carried more warheads (up to ten) than the Topol-M. The Russians developed the RS-24 to enable them to use all the additional warheads to penetrate American missile defenses.
At one point Russia planned to develop a liquid-fuel ICBM to replace its RS-18 and RS-20 (SS-18) ICBMs. The prototype was built but not tested. Russia had also announced plans to replace the old liquid-fuel missiles with the Topol M and this plan is apparently being implemented with the RS-24. It was never explained why they are sticking with liquid-fuel technology for the Cold War era “heavy” missiles. It might have something to do with the liquid-fuel missiles being able to lift heavier loads, making it possible to use them to also launch satellites. The liquid fueled missiles weighed 100-220 tons and had warhead weights of 5-9 tons. In contrast, all American ICBMs (including those launched from subs) are solid fueled and have a warhead weight similar to the Topol (about a ton). Russian SLBMs (Sea Launched ICBMs) also have the one ton warhead.
Russia continues to test launch older RS-18 and RS-20 ICBMs. Russia still has over a hundred (out of a 1980s peak of 360) RS-18s in service and expects to keep some of them active into the next decade or until replaced by the new design. The test firings for most of the last decade have been successful, and other quality-control tests have come back positive. Despite the post-Cold War collapse of the Russian military, cash and quality personnel kept going to the missile forces, which are the final defense of the largest nation on the planet.