Missile R-39 (SS-N-20 Sturgeon)

The R-39, known to NATO as the SS-N-20 Sturgeon, commenced its development journey in 1971 at the NII Mashinostroyeniya, with the Makeyev Rocket Design Bureau credited as the designer. The design received official endorsement in 1973. Initial test flights, beginning in 1979, encountered significant difficulties, particularly with the solid-fuel boost engines, leading to a high failure rate in early trials. Subsequent testing, conducted from a modified Typhoon-class submarine, proved more successful, paving the way for its deployment. The missile entered service with the Soviet Navy in 1983 and continued its operational life with the Russian Navy following the dissolution of the Soviet Union. Its service concluded in 2004. A program for a successor, the R-39M Grom, was undertaken but ultimately cancelled after a series of test failures.

As an intercontinental submarine-launched ballistic missile, the R-39 featured a three-stage solid-fuel rocket engine, augmented by a liquid-fuel post-boost unit. This configuration enabled the missile to carry multiple independently targetable reentry vehicle warheads of a thermonuclear nature. The launch sequence initiated with a gas generator located at the base of the launch tube. A notable characteristic of its underwater trajectory was the generation of a gaseous envelope around the missile by auxiliary motors, a design intended to reduce hydrodynamic resistance. Guidance was achieved through an astro-inertial system, providing a degree of accuracy for its substantial operational range.

The R-39 was deployed exclusively aboard Typhoon-class submarines. It entered service with the Soviet Navy in May 1983 and subsequently served with the Russian Navy until its decommissioning. Each submarine was designed to carry a complement of these missiles. At the peak of its deployment, a significant number of missiles were operational. Commencing in 1996, under the stipulations of arms control treaties such as START I and START II, a quantity of R-39 missiles were destroyed. Throughout the 1990s, both the Typhoon-class submarines and their R-39 missile armament were progressively withdrawn from active service. By 2004, all R-39 missiles had been decommissioned.