The R-12 Dvina was a theatre ballistic missile developed and deployed by the Soviet Union during the Cold War. Its GRAU designation was 8K63 (8K63U or 8K63У in Cyrillic for silo-launched version), and it was given the NATO reporting name of SS-4 Sandal. The R-12 rocket provided the Soviet Union with the capability to attack targets at medium ranges with a megaton-class thermonuclear warhead and constituted the bulk of the Soviet offensive missile threat to Western Europe. Deployments of the R-12 missile in Cuba caused the Cuban Missile Crisis in 1962. A total of 2335 missiles were produced; all were destroyed in 1993 under the START II treaty. As well as the single-stage ballistic technology, the R-12 Dvina had a two-stage capability that allowed payloads to be placed into low Earth orbit. The Iranian Shahab-4 missile is likely an offshoot of the R-12 Dvina. History Beginning OKB-586 formed from a spin-off of portions of Sergei Korolev's OKB-1 production infrastructure under the direction of Mikhail Yangel in the early 1950s. Soon after, he started the development of an improved strategic missile that would outperform the R-5, that Korolev was in the process of bringing into production. Yangel's design was based on combining the basic airframe from the R-5 with an engine developed from the R-11 Zemlya. The R-11 was a short-range missile that used nitric acid as an oxidizer and kerosene as a fuel and could be stored for extended periods of time. Valentin Glushko had long advocated using storable propellants, and proposed developing a new engine for the project. Earlier designs like the R-5 and R-7 used liquid oxygen as the oxidizer, and therefore had to be fueled immediately before launch, as the oxygen would "boil off" over time. He developed the RD-214 for the R-12, which consisted of four combustion chambers sharing a common turbopump assembly. The pumps were powered by decomposing hydrogen peroxide, like earlier designs, to generate an exhaust. The new engine was too large to fit in the existing R-5 airframe, so a conical tail section was added to hold the engine. Nikolay Pilyugin, head of the leading control system bureau, convinced Yangel to introduce a fully autonomous control system in the R-12 instead of the traditional radio control that had been used on earlier missiles. The R-5, for instance, used an inertial guidance system that had to be "fine tuned" by commands from ground radio