The R-7 Semyorka (,
GRAU
The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation (), commonly referred to by its transliterated acronym GRAU (), is a department of the Russian Ministry of Defense. It is subordinate to the Chief of ...
index: 8K71) was a
Soviet
The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...
missile developed during the
Cold War
The Cold War was a period of global Geopolitics, geopolitical rivalry between the United States (US) and the Soviet Union (USSR) and their respective allies, the capitalist Western Bloc and communist Eastern Bloc, which lasted from 1947 unt ...
, and the world's first
intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
. The R-7 made 28 launches between 1957 and 1961. A derivative, the
R-7A, was operational from 1960 to 1968. To the West it was unknown until its launch (later it would get the
NATO reporting name
NATO uses a system of code names, called reporting names, to denote military aircraft and other equipment used by post-Soviet states, former Warsaw Pact countries, China, and other countries. The system assists military communications by providi ...
SS-6 Sapwood). In modified form, it launched
Sputnik 1
Sputnik 1 (, , ''Satellite 1''), sometimes referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program ...
, the first artificial satellite, into orbit, and became the basis for the
R-7 family which includes
Sputnik
Sputnik 1 (, , ''Satellite 1''), sometimes referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space progra ...
,
Luna
Luna commonly refers to:
* Earth's Moon, named "Luna" in Latin, Spanish and other languages
* Luna (goddess)
In Sabine and ancient Roman religion and myth, Luna is the divine embodiment of the Moon (Latin ''Lūna'' ). She is often presented as t ...
,
Molniya,
Vostok, and
Voskhod space launchers, as well as later
Soyuz
Soyuz is a transliteration of the Cyrillic text Союз (Russian language, Russian and Ukrainian language, Ukrainian, 'Union'). It can refer to any union, such as a trade union (''profsoyuz'') or the Soviet Union, Union of Soviet Socialist Republi ...
variants. Various modifications are still in use and it has become the world's most reliable space launcher.
Description
The R-7 was long, in diameter and weighed ; it had a single stage with four strap on boosters powered by
rocket engine
A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed Jet (fluid), jet of high-temperature gas produced by the combustion of rocket propellants stor ...
s using
liquid oxygen
Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing.
Physical ...
(LOX) and
kerosene
Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...
and capable of delivering its payload up to , with an accuracy (
CEP) of around . A single
thermonuclear warhead could be carried with a nominal yield of 3
megatons of TNT. The launch was boosted by four strap-on
liquid rocket boosters with a central 'sustainer' engine powering the central core. Each strap-on booster included two
vernier thruster
A vernier thruster is a rocket engine used on a spacecraft or launch vehicle for fine adjustments to the attitude or velocity. Depending on the design of a craft's maneuvering and stability systems, it may simply be a smaller thruster complement ...
s and the core stage included four. The guidance system was inertial with radio control of the vernier thrusters.
The widely used nickname for the R-7 launcher, "Semyorka", is a rough translation of "old number seven" in Russian.
Development

Design work began in 1953 at
OKB-1
S.P. Korolev Rocket and Space Corporation "Energia" () is a Russian manufacturer of spacecraft and space station components. Its name is derived from the Russian word for energy and is also named for Sergei Korolev, Sergei Pavlovich Korolev, th ...
in Kaliningrad in Moscow Oblast (presently
Korolyov, Moscow Oblast
Korolyov or Korolev ( rus, Королёв, p=kərɐˈlʲɵf) is an industrial city in Moscow Oblast, Russia, well known as the cradle of Soviet and Russian space exploration. As of the 2010 Census, its population was 183,402, the largest as a ...
) and other divisions with the requirement for a missile with a launch mass of 170 to 200 tons, range of 8,500 km and carrying a nuclear warhead, powerful enough to launch a nuclear warhead against the United States. In late 1953 the warhead's mass was increased to 5.5 to 6 tons to accommodate the then planned
thermonuclear bomb. On 20 May 1954 the
USSR Council of Ministers
The Council of Ministers of the Union of Soviet Socialist Republics ( rus, Совет министров СССР, r=Sovet Ministrov SSSR, p=sɐˈvʲet mʲɪˈnʲistrəf ˌɛsˌɛsˌɛsˈɛr), sometimes abbreviated as Sovmin or referred to as the ...
approved the development of the R-7.
The principle of a staged missile, also known as a "rocket packet", was first proposed by
Mikhail Tikhonravov at NII-4 in 1947. Korolev became aware of this proposal in 1948 and supported further base studies at NII-4 in 1949–50. This was further refined by
Dmitry Okhotsimsky's
Department of Applied Mathematics in 1951 and expanded by Korolev's OKB-1 in 1952–53, which concluded that a core and four strap on boosters as the preferred model, which the R-7 used.
To lift the 5.5 ton payload required a redesign of the existing RD-105 and RD-106 engines.
Valentin Glushko's OKB-456 combined four combustion chambers using a single turbo pump, which provided a cumulative higher thrust than a single engine. Other advantages included an overall lower engine weight and simpler design, test and construction, via standardisation. The main engines for the central core and strap on boosters all used the four combustion chamber configuration. The four strap on propulsion engines were powered by the
RD-107 engine providing a sea level thrust of 83 tons, each with two
vernier engines to assist with steering. The central core's
RD-108 engine provided sea level thrust of 75 tons and included four vernier engines utilized for steering.
The rocket had some key features to it that made it unique. Instead of using jet vanes for control, which increased resistance generated at the engine nozzle exhaust outlet, the R-7 used special control engines for steering. These same engines served as the last stage's
vernier thruster
A vernier thruster is a rocket engine used on a spacecraft or launch vehicle for fine adjustments to the attitude or velocity. Depending on the design of a craft's maneuvering and stability systems, it may simply be a smaller thruster complement ...
s. Because of clustered design, each booster had its own propellant tanks. The design team had to develop a system to regulate the propellant component consumption ratio and to synchronize the consumption between the boosters.
Instead of a free-standing missile which was launched from a horizontal pad, it turned out that assembling a cluster of a central core and four boosters on the pad is almost impossible without it falling apart. Also, a wind gust could knock the unfuelled missile off of the pad. The solution was to eliminate the pad and to suspend the entire rocket in the
truss
A truss is an assembly of ''members'' such as Beam (structure), beams, connected by ''nodes'', that creates a rigid structure.
In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so ...
es that bear both vertical weight load as well as horizontal wind forces. The launch system simulated flight conditions with strap-on boosters pushing the central core forward.
Testing
The existing testing site at
Kapustin Yar
Kapustin Yar () is a Russian military training area and a rocket launch complex in Astrakhan Oblast, about 100 km east of Volgograd. It was established by the Soviet Union on 13 May 1946. In the beginning, Kapustin Yar used technology, material ...
was inadequate for the testing required for the R-7. Therefore a new site in Kazakhstan that would eventually become the
Baikonur Cosmodrome
The Baikonur Cosmodrome is a spaceport operated by Russia within Kazakhstan. Located in the Kazakh city of Baikonur, it is the largest operational space launch facility in terms of area. All Russian Human spaceflight, crewed spaceflights are l ...
was approved on 12 February 1955. The first series of test commenced when a flight-ready vehicle was delivered on 1 May 1957, and flown on 15 May. A fire broke out in one of the strap-on boosters almost immediately at liftoff. The missile broke away from the booster 88 seconds after liftoff and crashed downrange. During the next attempt on 11 June an electrical short caused the missile to start rolling uncontrollably and disintegrate 33 seconds after liftoff.
The first successful long flight, of , was made on 21 August 1957 with the missile reaching the target at
Kamchatka
The Kamchatka Peninsula (, ) is a peninsula in the Russian Far East, with an area of about . The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and western coastlines, respectively.
Immediately offshore along the Pacific ...
, however the dummy warhead disintegrated in the upper atmosphere. Five days later, TASS announced that the Soviet Union had successfully tested the worlds's first intercontinental ballistic missile.
A second successful test took place on 7 September 1957, with the missile again travelling . However again the dummy warhead disintegrated in the upper atmosphere. The first series of tests concluded on 10 July 1958.
The second test series incorporating improvements commenced on 24 December 1958 and concluded on 27 December 1959. Seven of the eight test launches were successful. Problems were resolved during these intensive tests and the missile was declared operational on 20 January 1960.
Operational history
A
modified version of the missile (8K71PS) launched the world's first satellite into orbit when
Sputnik 1
Sputnik 1 (, , ''Satellite 1''), sometimes referred to as simply Sputnik, was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program ...
lifted off from Baikonur on 4 October 1957.
Sputnik 2
Sputnik 2 (, , ''Satellite 2'', or Prosteyshiy Sputnik 2 (PS-2, , ''Simplest Satellite 2'', launched on 3 November 1957, was the second spacecraft launched into Earth orbit, and the first to carry an animal into orbit, a Soviet space dog named ...
followed on 3 November 1957. Sputnik (8A91) subsequently launched
Sputnik 3 on 15 May 1958.
The first strategic-missile unit went on alert status on 15 December 1959 at
Plesetsk in the north-west of the USSR. An improved version, the
R-7A with a lighter warhead, all inertial guidance system and a range of 12,000 km, became the standard version once it reached operational status on 12 September 1960.
The costs of the system were high, mostly due to the difficulty of constructing in remote areas the large launch sites required. Besides the cost, the missile system faced other operational challenges. With the
U-2 overflights, the huge R-7 launch complexes could not be hidden and therefore could be expected to be destroyed quickly in any nuclear war. Also, the R-7 took almost twenty hours to prepare for launching, and it could not be left on alert for more than a day due to its
cryogenic fuel
Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in machinery that operates in space (e.g. rockets and satellites) where ordinary fuel cannot be used, d ...
system. Therefore, the Soviet force could not be kept on permanent alert and could have been subject to an air strike before launching. These issues meant that the original planned fifty launch complexes were reduced to six, five for strategic forces, Site 31 at Baikonur and Sites 16, 41 and 43 (2 pads) at
Plesetsk and one for space launches at
Site 1,
Baikonur
Baikonur ( ; ) is a city in Kazakhstan on the northern bank of the Syr Darya river. It is currently leased and administered by the Russian Federation as an enclave until 2050. It was constructed to serve the Baikonur Cosmodrome with adminis ...
.
The limitations of the R-7 pushed the Soviet Union into rapidly developing second-generation missiles which would be more viable weapons systems, particularly the
R-16.
The R-7 was phased out of military service by mid-1968.
The R-7 turned out to be impractical as a weapon, but it became the basis for a series of Soviet
expendable space launch vehicles, including
Vostok family of launchers,
Molniya and
Soyuz family of launchers. , modified and modernized versions (
Soyuz 2 and the boosterless
2.1v variant) remain in service, having launched over 1,840 times. The R-7 is also a record holder in terms of longevity, with more than 50 years of service with its various modifications and has become the world's most reliable space launcher.
Variants
First is the Sputnik, most known for carrying Sputnik 1. Second is the Vostok, which carried Vostok-1 through Vostok-6. It also carried Voskhoud along with the better known Voskhoud-2 because of its first spacewalk and Monilya, which is less known due to its retirement. It also carries Soyuz which is still in operation after 60 years. Soyuz is Russia's most reliable rocket in use.
Operators
;: The
Strategic Missile Troops
The Strategic Rocket Forces of the Russian Federation or the Strategic Missile Forces of the Russian Federation (RVSN RF; ) is a separate combat arm of the Russian Armed Forces that controls Russia's land-based intercontinental ballistic miss ...
was the only operator of the Semyorka.
See also
*
List of missiles
Below is a list of missiles, sorted alphabetically into large categories and subcategories by name and purpose.
Other missile lists
Types of missiles:
* Conventional guided missiles
** Air-to-air missile
** Air-to-surface missile
** Anti-radia ...
*
R-7 space launchers
*
Soviet rocketry
*
Timeline of Russian innovation
References
Cited sources
*
*
External links
* from
S.P. Korolev Rocket and Space Corporation Energia, a Russian rocket and space contractor
The R-7 Missile history of its development
{{DEFAULTSORT:R-07
Cold War intercontinental ballistic missiles of the Soviet Union
Space launch vehicles of the Soviet Union
Sputnik
Soviet inventions
R-7 (rocket family)
R-007
Military equipment introduced in the 1950s