R-11 Zemlya

The R-11 Zemlya, GRAU index 8A61 was a Soviet tactical ballistic missile. It is also known by its NATO reporting name SS-1 Scud-A. It was the first of several similar Soviet missiles to be given the reporting name Scud.

The R-11 originated from a 1951 requirement for a ballistic missile with similar performance to the German V-2 rocket, but half its size. With the Wasserfall, an anti-aircraft version of the V-2, as a model the R-11 was developed by engineer Victor Makeev, who was then working in OKB-1, headed by Sergey Korolyov. The two men disagreed over the propulsion of the missile, with Korolev favouring the use of liquid oxygen, while Makeev advocated the use of toxic, but storable fuel. Makeev's version, that first flew on 18 April 1953, was fitted with an Isayev engine using RP-1 and nitric acid as a propellant. On 13 December 1953, a production order was passed with SKB-385 in Zlatoust, 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. The definitive R-11M, designed to carry a nuclear warhead, was accepted officially into service on 1 April 1958. The launch system received the GRAU index 8K11.

Like the V-2, the R-11 relied on inertial guidance, and its flight was controlled by four graphite vanes in the engine exhaust, that were active only while the motor was burning. The R-11M had a maximum range of 270 kilometres, but when carrying a nuclear warhead, this was reduced to 150 kilometres. At maximum range, it was found to have an average range error 1.19 kilometres and an azimuth error of 0.66 kilometres. It was used as a mobile nuclear strike vector, giving the Soviet 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 an IS-2 tank, that became its first transporter erector launcher. The only payload was a nuclear warhead with an estimated yield of 50 kilotons.

A naval variant, the R-11FM (SS-N-1 Scud-A) was first tested at Kapustin Yar in February 1955, and was first launched from a converted Project 611 (Zulu class) submarine in September of the same year. While the initial design was done by Korolev's OKB-1, the programme was transferred to Makeev's SKB-385 in August 1955. It became operational in 1959 as the D-1 launch system, the world's first submarine-launched ballistic missile (SLBM), and was deployed onboard Project 611 and Project 629 (Golf Class) submarines, until its replacement by the R-13 in 1961 (SS-N-4) and the R-21 (SS-N-5) in 1963. During its service, 77 launches were conducted, of which 59 were successful. The success of the R-11FM established Makeev as the main designer of submarine-launched weapons for the Soviet military.