for orbiting lightweight scientific and military payloads. A total of 123 were flown, of which eight failed to attain orbit. In 1977, the R-12 and 11K63 were retired from use. Description Overview The R-12 is a single-stage rocket with a separable single reentry vehicle. In the integrated fuel tanks the oxidizer was put forward of the fuel tank, separated by an intermediate plate. During flight this allowed the oxidizer from the lower unit to be spent first, 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. The R-12 was deployed at both soft launch pads and hard silos. The standard yield was 2.3 megatons. Conventional explosives or chemical weapons could have been used as well. R-12 steps of readiness Readiness nr. 4 (constant). The missile was in the hangar. The gyroscopes (control devices) and the explosive charge were unconnected, the missile was unfilled. The missile could stay so for seven years (factory-guaranteed service time). It would take 3 hours and 25 minutes to start. Readiness nr. 3 (elevated). The missile was in the hangar. The gyroscopes and the explosive charge were connected. The missile could stay so for three years. It would take 2 hours and 20 minutes to start. Readiness nr. 2 (first step elevated). The missile was carried to the starting ground, the gyroscopes were started, and initial data inserted. Petrol tanks stood next to the missile. The missile could stay so for three months. It would take 1 hour to start. Readiness nr. 1 (total). The missile was filled up and directed, but the starting mixture gas was not tanked up. The missile could stay so for one month. It would take 30 minutes to start. Operators Strategic Rocket Forces 58th Rocket Division other rocket divisions References Podvig, Pavel. (2001) Russian Strategic Nuclear Forces. Cambridge, MA: The MIT Press. R-12 rocket tech dossier External links Globalsecurity.org R-12 ICBM Theatre ballistic missiles Cold War missiles of the Soviet Union R-012 Cold War military equipment of Cuba Military equipment introduced in the 1950s