AKA: 15P084;8K84M;8K84UTTKh;RS-10;Sego;SS-11 Mod.2;UR-100M. Status: Operational 1970. Payload: 1,050 kg (2,310 lb). Thrust: 876.00 kN (196,932 lbf). Gross mass: 50,100 kg (110,400 lb). Height: 18.90 m (62.00 ft). Diameter: 2.00 m (6.50 ft). Span: 2.00 m (6.50 ft).
The 8K84M was an improved version of the UR-100 with an improved empty mass fraction, a new guidance system, countermeasures capability, and post-boost manoeuvrability to defeat enemy anti-ballistic missile systems. Development was authorised on 9 December 1965. Twelve trial flights were conducted between 23 July 1969 and 15 March 1971. The system was formally accepted by the military on 3 October 1972. The first regiment became operational at Khmelnitskiy on 1 March 1970.
Tests were made with a radar system to provide improved accuracy with a one megaton warhead at 9200 km range, but this was not adopted for service. Although this missile is often referred to as the UR-100M, this designation was applied within the design bureau to a naval version of the UR-100 developed by Chelomei in 1962-1964, but not selected for full development or production. Total Number Built 590.