R-29RM Shtil

R-29RM Shtil, NATO SS-N-23 Skiff, was developed as a liquid-fueled submarine-launched ballistic missile for Project 667BDRM Delta IV ballistic-missile submarines. It extended the R-29 family and entered Soviet service in the 1980s. The missile later formed the basis for modernization programs such as Sineva and Layner, which kept Delta IV boats strategically relevant. The current page category says ICBM, but the accurate platform category is SLBM with intercontinental range.

Technically, R-29RM is a submarine-launched ballistic missile using liquid propulsion and multiple stages. CSIS describes the SS-N-23 family with long range and multiple-warhead payload options. Liquid-fuel SLBMs are more complex than solid-fuel designs, but Soviet/Russian engineers achieved high performance and payload efficiency. The missile's integration with Delta IV submarines gives it survivability through undersea basing, while later upgrades improved reliability, range, and penetration capability.

Operationally, R-29RM Shtil served as a core weapon of Delta IV-class SSBNs. Its role was strategic deterrence: submarines carrying these missiles could patrol and preserve retaliatory strike capability. Post-Soviet Russia extended the family through Sineva, demonstrating the value of modernizing existing missile-submarine pairings. The missile is important because it sustained Russia's sea-based nuclear force through periods when new submarine and missile programs were delayed or unevenly funded.