The RS-28 Sarmat (Russian: ??-28 ??????,[5] named after the Sarmatians;[6] NATO reporting name: SS-X-29[7] or SS-X-30[8]), known as "Satan II", is a Russian liquid-fueled, MIRV-equipped super-heavy intercontinental ballistic missile (ICBM) produced by the Makeyev Rocket Design Bureau since 2009.[5][9] It is intended to replace the R-36M ICBM (SS-18 'Satan') in Russia's arsenal.

The Sarmat is one of six new Russian strategic weapons unveiled by Russian president Vladimir Putin on 1 March 2018.[12] The RS-28 Sarmat made its first test flight on 20 April 2022,[13] and as of December 2021, the Russian government expected the missile to enter service in 2022.[14] On 16 August 2022, a state contract was signed for the manufacture and supply of the Sarmat strategic missile system.

The RS-28 Sarmat will be capable of carrying about 10 tonnes of payload,[32] for either up to 10 heavy or 15 light MIRV warheads,[33] and up to 24 Avangard hypersonic glide vehicles (HGVs)[34] or a combination of warheads and several countermeasures against anti-ballistic missile systems.[35][36] The Russian Ministry of Defense said that the missile is Russia's response to the U.S. Prompt Global Strike system.[17]

Sarmat has a short boost phase, which shortens the interval when it can be tracked by satellites with infrared sensors, such as the U.S. Space-Based Infrared System, making it more difficult to intercept.[37][38][39] It is speculated[by whom?] that the Sarmat could fly a trajectory over the South Pole, completely immune to any current missile defense system,[38] and that it has the Fractional Orbital Bombardment (FOBS) capability.[10]

According to various sources, RS-28's launch sites are to be equipped with the "Mozyr"[40] active protection system, designed to negate a potential adversary's first strike advantage by discharging a cloud of metal arrows or balls kinetically destroying incoming bombs, cruise missiles and ICBM warheads at altitudes of up to 6 km.