The R-29RM Shtil was a liquid propellant, submarine-launched ballistic missile in use by the Russian Navy. It had the alternate Russian designations RSM-54 and GRAU index 3M27. It was designed to be launched from the Delta IV submarine, each of which is capable of carrying 16 missiles. The R-29RM could carry four 100 kiloton warheads and had a range of about 8,500 kilometres (5,300 mi). They were replaced with the newer R-29RMU2 Sineva and later with the enhanced variant R-29RMU2.1 Layner.

A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead and allows a single launched missile to strike several targets. Submarine-launched ballistic missiles operate in a different way from submarine-launched cruise missiles.