The RPK-2 Viyuga (Russian: РПК-2 Вьюга, meaning blizzard), also designated 81R, and identified by NATO as Starfish and the United States Department of Defense as SS-N-15, is a Soviet submarine-launched, nuclear-armed anti-submarine missile system, launched exclusively through 533mm torpedo tubes. The system was designed in Sverdlovsk, Russian SFSR in 1960s.
Analogous to the now retired Subroc missile carried by US Navy submarines, it is designed to be fired from a 533 mm (21 in) torpedo tube. It is boosted by a choice of mechanisms depending on model before clearing the water, firing a solid fuel rocket and delivering its payload up to 45 km (28 mi) away. The payload ranges from a simple depth charge to a 200 kt nuclear warhead.
The RPK-2 uses a 82R torpedo or 90R nuclear depth charge in the 533 mm version, and a 83R torpedo carrying[clarification needed] or 86R nuclear depth charge in 650 mm version.
Both submarine- and surface-launched versions exist. The surface-launched versions are used by the Slava, Kirov, Neustrashimyy and Udaloy classes. The submarine-launched versions are used by the Akula, Oscar, Typhoon, Delta, Kilo, and Borei classes. However, the munition package used in either is identical and hence the ship-launched version is launched into the water and submerges before firing its engines.