R-7 Semyorka
Encyclopedia
The R-7 was a Soviet
missile developed during the Cold War
, and the world's first intercontinental ballistic missile
. The R-7 made 28 launches between 1957 and 1961, but was never deployed operationally. A derivative, the R-7A
, was deployed from 1960 to 1968. To the West it was known by the NATO reporting name
SS-6 Sapwood and within the Soviet Union by the GRAU
index 8K71. In modified form, it launched Sputnik 1
, the first artificial satellite, into orbit, and became the basis for the R7 family which includes Sputnik, Luna
, Molniya
, Vostok
, and Voskhod
space launchers
, as well as later Soyuz
/L
/U
/U2
/FG
/2 variants.
The widely used nickname for the R-7 launcher, "semyorka", means (colloquially, affectionately) "the digit 7" or a "group of seven" (usually people rather than inanimate objects) in Russian
.
s using liquid oxygen
(LOX) and kerosene
and capable of delivering its payload at around 8,800 km, with an accuracy (CEP
) of around 5 km. A single thermonuclear warhead was carried with a nominal yield of 3 megatons of TNT
. The initial launch was boosted by four strap-on liquid rocket booster
s making up the first stage, with a central 'sustainer' motor powering through both the first and the second stage. Each strap-on booster included two vernier thruster
s and the core stage included four. The guidance system was inertial with radio control of the vernier thrusters.
Contrary to statements that the R-7 was based largely on experience and assistance of German scientists, the missile is noteworthy for looking beyond past achievements that had used German ideas. For example, instead of using jet vanes for control, which increased resistance generated at the engine nozzle exhaust outlet, the R-7 used special control engines. These same engines served as the last stage’s vernier thrusters.
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.
Starting from the R-1
, which was a copy of the German V-2
, a free-standing missile 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 missile off of the pad. The solution was to eliminate the pad and to suspend the entire rocket in the trusses 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.
The first testing of the new missile, codenamed 8K71, was on May 15, 1957 from Baikonur Cosmodrome
. A fire in a strap-on rocket led to an unintended crash 400 km from the site. Following another unsuccessful test the first successful long flight, of 6,000 km, was made on August 21. It was announced by TASS on August 26. A modified version of the missile (8K71PS) placed Sputnik 1
in orbit from Baikonur on October 4 and Sputnik 2
on November 3.
Following these first tests certain modifications were found to be needed and test flights were not completed until December 1959. The additional development resulted in the 8K74 (also known as R-7A), which was lighter, had better navigation systems, more powerful engines, extended its range to 12,000 km by carrying more fuel, and increased payload to 5,370 kg. The warhead was tested on Novaya Zemlya
in October 1957 and again in 1958, yielding an estimated 2.9 Mt of TNT.
in north-west Russia. On 15 December 1959 the R-7 missile was tested at Plesetsk for the first time. The missiles were fully deployed by 1962.
Total service was limited to no more than ten nuclear armed missiles active at any time. A single launch pad was operational at Baikonur
and from six to eight were in operation at Plesetsk.http://data-freeway.com/plesetsk/bsemyorka_8.htm
The costs of the system were high, mostly due to the difficulty of constructing in remote areas the large launch sites required. At one point, each launch site was projected to cost 5% of the Soviet defence budget. However, these huge costs were not unique for a first generation missile and the US experienced similar problems.
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 system. Therefore, the Soviet force could not be kept on permanent alert, and could have been subject to an air strike before launching. Additionally the huge payload for which it was designed, adapted to early heavy H-bombs, became irrelevant with the coming of lighter bomb technology.
The limitations of the R-7 pushed the Soviet Union into rapidly developing second-generation missiles which would be more viable weapons systems. The R-7 was phased out from military service by 1968.
While the R-7 turned out to be impractical as a weapon, it became the basis for a series of Soviet expendable space launch vehicles
. The derivatives of the R-7 missile became successful space launch vehicles, which are still being used in modified form.
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
missile developed during the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
, and the world's first intercontinental ballistic missile
Intercontinental ballistic missile
An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...
. The R-7 made 28 launches between 1957 and 1961, but was never deployed operationally. A derivative, the R-7A
R-7A Semyorka
The R-7A Semyorka, GRAU index 8K74, was an early Soviet intercontinental ballistic missile derived from the earlier R-7 Semyorka. It was the only member of the R-7 family of rockets to be deployed as an operational missile. The R-7A first flew on 23 December 1959, entered service on 31 December of...
, was deployed from 1960 to 1968. To the West it was known by the NATO reporting name
NATO reporting name
NATO reporting names are classified code names for military equipment of the Eastern Bloc...
SS-6 Sapwood and within the Soviet Union by the GRAU
Grau
Grau is a German word meaning "gray" and a Catalan word meaning "grade". It may refer to:* BAP Almirante Grau , a De Zeven Provinciën class cruiser in service with the Peruvian Navy* Grau Käse, Tyrolean grey cheese...
index 8K71. In modified form, it launched Sputnik 1
Sputnik 1
Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space...
, the first artificial satellite, into orbit, and became the basis for the R7 family which includes Sputnik, Luna
Luna (rocket)
The Luna 8K72 vehicles were carrier rockets used by the Soviet Union for nine space probe launch attempts in the Luna programme between 1958-09-23 and 1960-04-16...
, Molniya
Molniya (rocket)
Molniya 8K78 was a modification of the well-known R-7 Semyorka rocket and had four stages.This derivative of the original three stage Vostok rocket was especially designed to bring high flying satellites into orbit or to launch probes to other planets. The first launch of this rocket was on...
, Vostok
Vostok rocket
Vostok was a family of rockets derived from the Soviet R-7 Semyorka ICBM designed for the human spaceflight programme. This family of rockets launched the first artificial satellite and the first manned spacecraft in human history...
, and Voskhod
Voskhod rocket
The Voskhod rocket was a derivative of the Soviet R-7 ICBM designed for the human spaceflight programme but later used for launching Zenit reconnaissance satellites. It combined the R-7 with an upper stage that had been originally designed to launch interplanetary probes.There was only one main...
space launchers
Expendable launch system
An expendable launch system is a launch system that uses an expendable launch vehicle to carry a payload into space. The vehicles used in expendable launch systems are designed to be used only once , and their components are not recovered for re-use after launch...
, as well as later Soyuz
Soyuz (rocket)
The Soyuz was a Soviet expendable carrier rocket designed by OKB-1 and manufactured by State Aviation Plant No. 1 in Samara, Russia. It was used to launch Soyuz spacecraft as part of the Soyuz programme, initially on unmanned test flights, followed by the first 19 manned launches of the...
/L
Soyuz-L
The Soyuz-L , GRAU index 11A511L was a Soviet expendable carrier rocket designed by OKB-1 and manufactured by State Aviation Plant No. 1 in Samara, Russia. It was used for tests of the LK Lunar lander in low Earth orbit, as part of the Soviet lunar programme.The Soyuz-L was essentially a two stage...
/U
Soyuz-U
The Soyuz-U launch vehicle is an improved version of the original Soyuz LV. Soyuz-U is part of the R-7 family of rockets based on the R-7 Semyorka missile. Members of this rocket family were designed by the TsSKB design bureau and constructed at the Progress Factory in Samara, Russia....
/U2
Soyuz-U2
The Soyuz-U2 was a Soviet, later Russian, carrier rocket. It was derived from the Soyuz-U, and a member of the R-7 family of rockets...
/FG
Soyuz-FG
The Soyuz-FG launch vehicle is an improved version of the Soyuz-U, from the R-7 family of rockets, designed and constructed by TsSKB-Progress in Samara...
/2 variants.
The widely used nickname for the R-7 launcher, "semyorka", means (colloquially, affectionately) "the digit 7" or a "group of seven" (usually people rather than inanimate objects) in Russian
Russian language
Russian is a Slavic language used primarily in Russia, Belarus, Uzbekistan, Kazakhstan, Tajikistan and Kyrgyzstan. It is an unofficial but widely spoken language in Ukraine, Moldova, Latvia, Turkmenistan and Estonia and, to a lesser extent, the other countries that were once constituent republics...
.
Description
The R-7 was 34 m long, 3 m in diameter and weighed 280 metric tons; it was two-stage, powered by rocket engineRocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...
s using liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
(LOX) and kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
and capable of delivering its payload at around 8,800 km, with an accuracy (CEP
Circular error probable
In the military science of ballistics, circular error probable is an intuitive measure of a weapon system's precision...
) of around 5 km. A single thermonuclear warhead was carried with a nominal yield of 3 megatons of TNT
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...
. The initial launch was boosted by four strap-on liquid rocket booster
Liquid Rocket Booster
A Liquid Rocket Booster is similar to a solid rocket booster attached to the side of a rocket to give it extra lift at takeoff. A Liquid Rocket Booster has fuel and oxidiser in liquid form, as opposed to a solid rocket or hybrid rocket....
s making up the first stage, with a central 'sustainer' motor powering through both the first and the second stage. Each strap-on booster included two vernier thruster
Vernier thruster
A vernier thruster is a thruster used on a spacecraft for attitude control. It is a smaller thrust motor than main attitude control motors and is used for fine adjustments to the attitude or velocity of a spacecraft...
s and the core stage included four. The guidance system was inertial with radio control of the vernier thrusters.
Development
Design work began in 1953 at OKB-1 in Kaliningrad in Moscow oblast (presently Korolev, Moscow Oblast) and other divisions with the requirement for a two-stage missile of 170 tons with a range of 8,000 km carrying a 3000 kg warhead. Following first ground tests in late 1953 the initial design was heavily reworked and the final design was not approved until May 1954.Contrary to statements that the R-7 was based largely on experience and assistance of German scientists, the missile is noteworthy for looking beyond past achievements that had used German ideas. For example, instead of using jet vanes for control, which increased resistance generated at the engine nozzle exhaust outlet, the R-7 used special control engines. These same engines served as the last stage’s vernier thrusters.
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.
Starting from the R-1
R-1 (missile)
The R-1 rocket was a copy of the German V-2 rocket manufactured by the Soviet Union. Even though it was a copy, it was manufactured using Soviet industrial plants and gave the Soviets valuable experience which later enabled the USSR to construct its own much more capable rockets.In 1945 the...
, which was a copy of the German V-2
V-2 rocket
The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...
, a free-standing missile 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 missile off of the pad. The solution was to eliminate the pad and to suspend the entire rocket in the trusses 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.
The first testing of the new missile, codenamed 8K71, was on May 15, 1957 from Baikonur Cosmodrome
Baikonur Cosmodrome
The Baikonur Cosmodrome , also called Tyuratam, is the world's first and largest operational space launch facility. It is located in the desert steppe of Kazakhstan, about east of the Aral Sea, north of the Syr Darya river, near Tyuratam railway station, at 90 meters above sea level...
. A fire in a strap-on rocket led to an unintended crash 400 km from the site. Following another unsuccessful test the first successful long flight, of 6,000 km, was made on August 21. It was announced by TASS on August 26. A modified version of the missile (8K71PS) placed Sputnik 1
Sputnik 1
Sputnik 1 ) was the first artificial satellite to be put into Earth's orbit. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957. The unanticipated announcement of Sputnik 1s success precipitated the Sputnik crisis in the United States and ignited the Space...
in orbit from Baikonur on October 4 and Sputnik 2
Sputnik 2
Sputnik 2 , or Prosteyshiy Sputnik 2 ), was the second spacecraft launched into Earth orbit, on November 3, 1957, and the first to carry a living animal, a dog named Laika. Sputnik 2 was a 4-meter high cone-shaped capsule with a base diameter of 2 meters...
on November 3.
Following these first tests certain modifications were found to be needed and test flights were not completed until December 1959. The additional development resulted in the 8K74 (also known as R-7A), which was lighter, had better navigation systems, more powerful engines, extended its range to 12,000 km by carrying more fuel, and increased payload to 5,370 kg. The warhead was tested on Novaya Zemlya
Novaya Zemlya
Novaya Zemlya , also known in Dutch as Nova Zembla and in Norwegian as , is an archipelago in the Arctic Ocean in the north of Russia and the extreme northeast of Europe, the easternmost point of Europe lying at Cape Flissingsky on the northern island...
in October 1957 and again in 1958, yielding an estimated 2.9 Mt of TNT.
Operational history
The first strategic-missile unit became operational on 9 February 1959 at PlesetskPlesetsk
Plesetsk is an urban locality Plesetsk is an urban locality Plesetsk is an urban locality (a work settlement and the administrative center of Plesetsky District, Arkhangelsk Oblast, Russia, situated about northeast of Moscow and south of Arkhangelsk. Municipally, it is the administrative...
in north-west Russia. On 15 December 1959 the R-7 missile was tested at Plesetsk for the first time. The missiles were fully deployed by 1962.
Total service was limited to no more than ten nuclear armed missiles active at any time. A single launch pad was operational at Baikonur
Baikonur
Baikonur , formerly known as Leninsk, is a city in Kyzylorda Province of Kazakhstan, rented and administered by the Russian Federation. It was constructed to service the Baikonur Cosmodrome and was officially renamed Baikonur by Russian president Boris Yeltsin on December 20, 1995.The shape of the...
and from six to eight were in operation at Plesetsk.http://data-freeway.com/plesetsk/bsemyorka_8.htm
The costs of the system were high, mostly due to the difficulty of constructing in remote areas the large launch sites required. At one point, each launch site was projected to cost 5% of the Soviet defence budget. However, these huge costs were not unique for a first generation missile and the US experienced similar problems.
Besides the cost, the missile system faced other operational challenges. With the U-2
Lockheed U-2
The Lockheed U-2, nicknamed "Dragon Lady", is a single-engine, very high-altitude reconnaissance aircraft operated by the United States Air Force and previously flown by the Central Intelligence Agency . It provides day and night, very high-altitude , all-weather intelligence gathering...
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 system. Therefore, the Soviet force could not be kept on permanent alert, and could have been subject to an air strike before launching. Additionally the huge payload for which it was designed, adapted to early heavy H-bombs, became irrelevant with the coming of lighter bomb technology.
The limitations of the R-7 pushed the Soviet Union into rapidly developing second-generation missiles which would be more viable weapons systems. The R-7 was phased out from military service by 1968.
While the R-7 turned out to be impractical as a weapon, it became the basis for a series of Soviet expendable space launch vehicles
Expendable launch system
An expendable launch system is a launch system that uses an expendable launch vehicle to carry a payload into space. The vehicles used in expendable launch systems are designed to be used only once , and their components are not recovered for re-use after launch...
. The derivatives of the R-7 missile became successful space launch vehicles, which are still being used in modified form.
External links
- Rocket R-7 from S.P. Korolev Rocket and Space Corporation EnergiaS.P. Korolev Rocket and Space Corporation EnergiaOAO S.P. Korolev Rocket and Space Corporation Energia , also known as RKK Energiya, is a Russian manufacturer of spacecraft and space station components...
, a RussiaRussiaRussia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
n rocket and space contractor - The R-7 Missile, history of its development