| R-11 Zemlya | |
|---|---|
 | |
| Type | Short-range ballistic missile |
| Place of origin | Soviet Union |
| Service history | |
| In service | 1956-1978 |
| Production history | |
| Produced | 1956-1962 |
| Specifications | |
| Mass | 5.4 tonnes |
| Length | 10 604 mm |
| Diameter | 880 mm |
| Warhead | HE,nuclear |
TheR-11 Zemlya (Russian:Р-11 Земля,lit. 'Earth'),[1]GRAU index8A61[2] was aSoviettactical ballistic missile. It is also known by itsNATOreporting nameSS-1b Scud-A. It was the first of several similar Soviet missiles to be given the reporting nameScud. VariantR-11M was accepted into service, with GRAU index9K51 (9К51).
The R-11 originated from a 1951 requirement for aballistic missile with similar performance to the GermanV-2 rocket, but half its size. With theWasserfall, an anti-aircraft version of the V-2, as a model the R-11 was developed by engineerVictor Makeev, who was then working inOKB-1, headed bySergey Korolyov. The two men agreed on the use ofRG-1 as the fuel, but disagreed over which oxidizer to use, with Korolev favouring the use ofliquid oxygen, while Makeev advocated the use of a storable but toxic oxidizer. Makeev's version, that first flew on 18 April 1953, was fitted with anIsayev engine usingRG-1 andnitric acid. On 13 December 1953, a production order was passed withSKB-385 inZlatoust, a factory dedicated to producing long-range rockets. In June 1955, Makeev was appointed chief designer of the SKB-385 to oversee the programme and, in July, the R-11 was formally accepted into military service.[2] The definitive R-11M, designed to carry a nuclear warhead, was accepted officially into service on 1 April 1958. The launch system received theGRAU index 9K51, the rocket itself 8K11, and the launcher 8U218.[3]
Like the V-2, the R-11 relied oninertial guidance, and its flight was controlled by fourgraphite vanes in the engine exhaust, that were active only while the motor was burning. The R-11M had a maximum range of 270 km (170 mi), but when carrying a nuclear warhead, this was reduced to 170 km (110 mi), hence an alternative designation R-170.[3] At maximum range, it was found to have an average range error 1.19 km (0.74 mi) and anazimuth error of 660 m (0.41 mi).[4] It was used as a mobile nuclear strike vector[clarification needed], giving theSoviet Army the ability to hit European targets from forward areas. To give the system sufficient mobility on the battlefield, the R-11 was mounted on the chassis of anIS-2 tank, that became its firsttransporter erector launcher 8U218. Main payload was a nuclear warhead with an estimated yield of 10, 20 or 40 kilotons.[3] There was alsoHE-Frag warhead 9N33 with 535 kg (1,179 lb) of explosive.[3]
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A naval variant, theR-11FM was first tested atKapustin Yar in February 1955, and was first launched from a convertedProject 611 (Zulu class) submarine in September of the same year.[5] While the initial design was done by Korolev's OKB-1, the programme was transferred to Makeyev's SKB-385 in August 1955.[2] It became operational in 1959 as the D-1 launch system, the world's firstsubmarine-launched ballistic missile (SLBM),[6] and was deployed onboard Project 611 andProject 629 (Golf Class) submarines, until its replacement by theR-13 in 1961 (SS-N-4) and theR-21 (SS-N-5) in 1963.[7] During its service, 77 launches were conducted, of which 59 were successful.[8] The success of the R-11FM established Makeev as the main designer of submarine-launched weapons for the Soviet Armed Forces, and the R-11FM served with the first generation SLBM submarine units of the Soviet Navy.
