R-13 (missile)

The R-13, known to NATO as the SS-N-4 Sark, was a Soviet submarine-launched ballistic missile and the first in the Soviet series to use four-chamber vernier engines for flight control instead of gas or aerodynamic surfaces. It was a single-stage missile burning storable liquid propellant, with a separable single reentry vehicle carrying a nuclear warhead that Western estimates placed at 1.2 to 2.0 megatons, though Russian sources give 1.0. Development was ordered in 1955 and 1956, flight tests ran at Kapustin Yar from 1959 to 1960, and the D-2 launch system with the R-13 was deployed on 13 October 1961 aboard Golf-class and Hotel-class submarines. During its service from 1960 to 1972, 225 of 311 launches succeeded. Western observers first saw models of it in Red Square parades and gave it the Sark name, and the page notes that some 1970s and 1980s Western sources mislabelled it SS-N-5 Serb, which is actually the R-21. Production ended in 1964 and the phase-out finished in 1975.