R-12 / SS-4 SANDAL
The R-12 was the first Soviet strategic missile using storable propellants and a completely autonomous inertial guidance system. The rocket provided a capability to attack strategic targets at medium ranges with its capability to deliver a megaton-class nuclear warhead. This system constituted the bulk of the Soviet offensive missile threat to Western Europe. It was deployed at both soft launch pads and hard silos.
The Sandal is a single-stage rocket with a separable single reentry vehicle. In the integrated fuel tanks the oxidizer was put ahead of the fuel tank, separated by an intermediate plate. During flight this allowed the oxidizer from the lower unit to be spent first thus improving in-flight stabilization. The propulsion system consists of four liquid propellant rocket motors with a common turbo pump unit. The flight control was carried out with the help of four carbon jet vanes, located in the nozzles of the rocket motors. The autonomous guidance and control system used center of mass normal and lateral stabilization devices, a velocity control system and a computer-assisted automatic range control system.
Its development was accepted on 13 August 1955 by the Ministerial Council and carried out by Yangel's OKB-586. The first tests were conducted at the test site in Kapustin Yar from 22 June 1957 through December 1958. The R-12 missile was introduced into the inventory on 04 March 1959 according to Russian sources, though Western intelligence believed that an initial operational capability was reached in late 1958.
Efforts to develop a railway based version of the R-12 missile were suspended.
The R-12 missile was surface-launched. However in September 1959 a series of experimental silo launches was conducted and subsequently in May 1960 the development of a new R-12 missile designated as R-12 U was begun. The R-12U was designed to be used with both soft surface launchers and hardened silos. The silo-launch complex of the R-12U missile comprised four launchers and was designated as "Dvina." The testing phase of the missile and the launch complex lasted from December 1961 through December, 1963.
The first public display of this system was in November 1960, and they were deployed to Cuba in the Fall of 1962.
The first five regiments with surface-based R-12 missiles were put on alert in May 1960, while the first regiment of silo-based missiles was placed on alert in January 1963. Reaction time was assessed by the West at one to three hours in the normal soft site readiness condition, and five to fifteen minutes in the normal hard site readiness condition. The allowable hold time in a highly alert condition (reaction time equals three to five minutes) is long--many hours for soft sites, and days for hard sites.
The R-12 and R-12U missiles reached their maximum operational launcher inventory of 608 in 1964-1966. Some soft-site phase-out began in 1968, with some hard-site phase-out beginning in 1972. In 1978 their phase out and replacement with mobile ground-launched SS-20 "Pioneer" missiles began.
The Intermediate-Range and Shorter-Range Nuclear Forces [INF] Treaty was signed in of December 1987 and entered into force in June 1988. The fundamental purpose of the INF Treaty was to eliminate and ban US and former USSR (FSU) ground-launched ballistic and cruise missiles, as well as associated support equipment, with ranges between 500 and 5500 kilometers. SS-4 and SS-5 missiles and components were eliminated at Lesnaya. The last of 149 Soviet SS-4 missiles was eliminated at the Lesnaya Missile Elimination Facility in May 1990.