AKA: 15A18;R-36MUTTKh;RS-20B;Satan;SS-18 Mod.4. Status: Operational 1979. Payload: 7,570 kg (16,680 lb). Gross mass: 211,100 kg (465,300 lb). Height: 32.62 m (107.03 ft). Diameter: 3.00 m (9.80 ft). Span: 3.05 m (10.00 ft).
The decree for an improved version of the R-36M with a new ten warhead MIRV bus, better guidance system, increased throw-weight, and increased range was issued on 16 August 1976. The draft project was completed in December 1976. A revised decree of 16 August 1977 may have included engine fixes urgently required for the deployed base of R-36M's. Flight trials began on 31 October 1977 and those with the new 15F183 warhead were completed in November 1979. On 18 September 1979 the first missiles were installed in replacement of R-36M's at Dombarovskiy, Uzhur, and Zhangiz-Tobe. On 17 December 1980 the first variant with the 15F183 bus was put into service. By 1983 all earlier R-36 and R-36M's had been replaced, and the R-36MUTTKh reached its peak deployment of 308 missiles. It seems a single-warhead version was never deployed. The R-36M was to have been replaced by a new missile in the 1990's, but the break-up of the Soviet Union resulted in severe financial constraints. Therefore, although the original rated storage life was ten years, evaluation of in-service rockets resulted in continual extension, to as much as 23 years. A test firing of an R-36MU that was 19 years 6 months old was made on 17 April 1997. On 21 April 1999 an R-36MU that had been stored for 20 years 9 months was successfully fired as a Dnepr space booster.
The 15F183 bus was 2.9 m in diameter and 8.1 m long and powered by a four-chamber liquid propellant engine.