This November 2022 needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this November 2022. Unsourced material may be challenged and removed.Find sources: "UR-100" – news · newspapers · books · scholar · JSTOR (November 2022) (Learn how and when to remove this message)
SS-11 Sego
Service history
In service21 July 1967 (document №705-235)–1974
Used bySoviet Union
Production history
Manufacturerdesign by OKB-52 of V.N.Chelomey, production by Khrunichev Machine-Building Plant, Omsk aviation facility №166 "Polyot", Orenburg aviation facility №47 "Strela"
Mass41.4-42.3 tonnes
Length16,930 mm
Diameter2,000 mm
Blast yield1 Mt by NII-1011, Chelyabinsk-70

Enginetwo-stage liquid fuel
  1. first stage 8S816 with a 15D2 module (three RD-0216 and one RD-0217 engines)
  2. second stage 8S817 with one 15D13 main and one four-nozzle 15D14 (RK-3) engines)
10,600 km
Accuracy1000–1400 metres CEP

The UR-100 (Russian: УР-100) was an intercontinental ballistic missile (ICBM) developed and deployed by the Soviet Union from 1966 to 1996. UR (УР) in its designation stood for Universal Rocket (Russian: Универсальная Ракета). It was known during the Cold War by the NATO reporting name SS-11 Sego and internally by the GRAU index 8K84. The Strela and Rokot carrier rockets were based on it.

The similar designation UR-100MR (Russian: УР-100МР) actually refers to an entirely different missile, the MR-UR-100 Sotka (SS-17 Spanker).


The UR-100 was a two-stage liquid-propellant lightweight ICBM. Initial versions carried a single warhead of 0.5 to 1.1 Mt yield, while later versions could carry three or six MIRV warheads. The missile was silo-launched. 15P784 silo design (by KBOM, Design Bureau of Common Machinery, of V.P.Barmin) was greatly simplified in comparison to earlier missiles. Facilities consisted of hardened, unstaffed silos controlled by a single central command post. This was the first soviet ICBM (8K84M, entered service on 3 October 1971) equipped with missile defense countermeasure "Palma" by NII-108 of V.Gerasimenko.[citation needed]

Variants and developments

Operational history

 Soviet Union
The UR-100 reached initial operational capability with the Strategic Rocket Forces in 1966, and by 1972, 990 launchers had been deployed. An additional 420 launchers of newer version missiles were added by 1976. The missile was deployed as a counterpart to the United States' LGM-30 Minuteman, and relied on numbers for effectiveness. Original versions were phased out during the 1970s, but 326 of the newer missiles (8K84M, UR-100N, UR-100NUTTH) remained in service by 1991. These were phased out completely by 1996. Strategic Rocket Forces was the only operator of the UR-100.[citation needed]

Formations included:

As a space launcher

The Strela and Rokot carrier rockets are based on the UR-100.[citation needed]

See also

This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. Please help improve this article by introducing more precise citations. (December 2014) (Learn how and when to remove this message)