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Voskhod, Soyuz Launch Vehicle
SL-4 A-2 with Planetary Upper Stage

In 1957, the Soviet Union launched the Sputnik 1, the first artificial satellite in the history of mankind, which was a sensational world event. Russia could keep the lead in space missions for a while after their success because of certain special measures. Russia did not start the production of a large rocket through one single effort but started the mission with a rocket consisting of a bundle of small rockets, applying the V-2 technology they received from the Nazis after their occupation.

The Soyuz is an upgraded version of the Vostok which became the first manned space flight in the world by Gagarin in 1961. The Soyuz is called the A-2 (SL-4) and the Vostok is called the A-1 (SL-3) both of which were nicknamed for a manned space ship. The improved vehicles of Soyuz class were already used by various missions including the first manned flight of the Voskhod in 1964 and other experimental flights before the first manned flight of the Soyuz in 1967.

The Soyuz (A-2/SL-4) premiered in 1963, with the development of a more powerful core second stage. The launch vehicle Voskhod ["Sunrise"] was first launched on November 16, 1963. The main differences in the new missile were in the third stage. As its used the newly developed block "I", which was much more powerful than the block "E", used earlier in the "Vostok". With the help of this rocket, space ships of the "Voskhod" series were launched into near-earth orbit. But most widely this rocket was used for launches of reconnaissance satellites of the Zenit series.

After the launch of the first single manned spacecraft "Vostok" in the Design Bureau-1 began to expand the program of human spaceflight and the creation of a multi-seat spacecraft Voskhod ["Sunrise"]. The Earth observation program from space was also expanded. The branch of #3 of OKB-1 and the plant "Progress" successfully mastered production of survey satellites "Zenit-2".

The issue of getting more detailed pictures was on the agenda, the development of the following type of Satellite-A detailed observation satellite "Zenit-4". The mass of spacecraft "Voskhod" and "Zenith-4" increased compared to its prototypes by more than 1000 kg. Launch vehicles "Vostok" (8K 72) and "Vostok-2" (8A92), with the help of which the first manned spacecraft and the first observation satellites, on energy characteristics could not bring new devices to working orbits.

Therefore, in compliance with the Regulation SM USSR #1150-451 from 27.11.61 and #1103-467 from 24 October 1962 was developed 11A57 "Sunrise" Launch Vehicle. Since 1961 many works on improvement of construction, working out, flight tests and operation of type R-7 (R-7a) had already been conducted by Branch #3 as the head design bureau. But it was the launch Vehicle 11A57 that became the first completely independent Azrabotkoj Kuibyshev Branch #3 OKB-1.

It was obtained from the 8K78 Molniya missile by replacing the fourth stage with an increased payload. For the first time, it was used to launch satellite reconnaissance satellites, the mass of which exceeded the capabilities of the Vostok missile. Allowed to take out manned ships with a crew of two or three people.

With the help of this rocket, multi-seat spacecraft "Voskhod" were put into orbit. Most widely this launch vehicle was used to launch the reconnaissance satellite Zenit, created on the basis of the spacecraft Vostok. As the first and second stages, the standard carrier rocket "R-7A" (without the GC and the RUP system) was used. The third step instead of the "E" block was the newly created much more powerful "I" block. Block "I" is developed on the basis of the design of the second stage of the intercontinental ballistic missile 8K75 "R-9". The rocket was first launched on November 16, 1963 and received the index 11A57.

This SLV has been the workhorse of the Soviet rocket program. Since 1964, all Soviet manned missions have relied on the SL-4. However, the largest program it supports is military and civilian photographic reconnaissance flights. It was used to launch the Soyuz, Progress and Biosats, as well as Kosmos observation satellites. It also launched the Voskhod manned vehicles. Over 900 Soyuz had been flown successfully from TT and PK. At one time it was launched 40-50 times a year, the Soyuz was by far the most launched SLV in the world.

The Soyuz is launched at the Baikonur Cosmodrome in Kazakhstan, at the Plesetsk Cosmodrome in the North of Russia and at the Guiana Space Centre in French Guiana to meet the needs of the commercial market and continuing to serve the needs of Russian government and other institutional and international programs. Soyuz LVs are produced in Samara, Russia, by the Samara Space Center, whose facilities have been designed to accommodate the production of up to four LVs per month. As a result of the continued demand from the Russian government, International Space Station activity and commercial orders, the Soyuz LV is in uninterrupted production at an average rate of 15 to 20 LVs per year with a capability to rapidly scale up to accommodate users’ needs. The Fregat upper stage is produced at Khimki, near Moscow, Russia by NPO Lavochkin, with a production rate up to 6 Fregat per year. The expected Soyuz launch rate at the Guiana Space Center, is 4 to 6 launches per year.

The Soyuz is one of the world's most reliable - and frequently used - launch vehicles. More than 1,600 launches have been made with Soyuz launchers to orbit satellites for telecommunications, Earth observation, weather, and scientific missions, as well as for manned flights. The basic Soyuz vehicle is considered a three-stage launcher in Russian terms, and is composed of a lower portion consisting of four boosters (first stage) and a central core (second stage); and an upper portion, consisting of the third stage, payload adapter and payload fairing. Liquid oxygen and kerosene are used as propellants in all three Soyuz stages.

The first stage's four boosters are assembled laterally around the second stage central core. The boosters are identical and cylindrical-conic in shape with the oxygen tank located in the coneshaped portion and the kerosene tank in the cylindrical portion. An NPO Energomash RD 107 engine with four main chambers and two gimbaled vernier thrusters is used in each booster. The vernier thrusters provide three-axis flight control.

Ignition of the first stage boosters and the second stage central core occur simultaneously on the ground. When the boosters have completed their powered flight during ascent, they are separated and the core second stage continues to function. First stage booster separation occurs when the predefined velocity is reached, which is at about 118 seconds after liftoff. An NPO Energomash RD 108 engine powers the Soyuz second stage. This engine differs from those of the boosters by the presence of four vernier thrusters, which are necessary for three-axis flight control of the launcher after the first stage boosters have separated. An equipment bay located atop the second stage operates during the entire flight of the first stage and second stages.

The third stage is linked to Soyuz second stage by a latticework structure. When the second stage's powered flight is complete, the third stage engine is ignited. Separation of the two stages occurs by the direct ignition forces of the third stage engine. A single-turbopump RD 0110 engine from KB KhA powers the Soyuz third stage. The third stage engine is fired for about 240 seconds, and cutoff occurs when the calculated velocity increment is reached. After cutoff and separation, the third stage performs an avoidance maneuver by opening an outgassing valve in the liquid oxygen tank.

Early Western Views

The Luna and Vostok version of the standard vehicle did not exploit the total potential of the first stages, and so an improved stage was built which began to fly as early as 1960. Its first public disclosure came in 1961 in connection with the Venus attempts of that year. The Luna upper stage was replaced by a stage 8 meters long. It was able to send about 1,500 kilograms of payload to the Moon, not counting the weight of an escape rocket, and over a period of time the capacity was raised. Without an escape rocket it was used to increase the Earth orbital capacity. The first announced use in Earth orbit was to put up 6,583 kilograms, and subsequently, the capacity has been described by them as 7,500 kilograms maximum. It was used for the pair of Voskhod manned flights, and has continued in use to the present time in the Soyuz manned flights. In addition it is the version most used in the Kosmos program for those flights which perform a military mission followed by recovery after some days. The Voskhod and Soyuz versions of A-2 are shown in figure 10.

It is the Soviet practice to disclose information only piecemeal about their vehicles. In the case of the Vostok it was years before they disclosed the thrust of the rockets or their number. The sole statistic beside the orbital weight was an output of 20 million horsepower, not a common measure for describing the power of rockets. As mentioned they later said the combined thrust was 600 metric tons from 6 engines.

When the Voskhod flights came, they said the rocket had 7 engines of 650 metric tons. No replica was put on display, so that analysis in the West was made more difficult. Subtraction of the announced thrust of the 5 core and booster engines seemed to leave 140 metric tons of thrust for an upper stage of 2 engines. This was not logical for the purposes or for the observed behavior of the flights. It is only in 1975 that we finally have a fresh Soviet statement on this rocket combination. First of all, they have adjusted downward the thrust of the central core rocket to list it at 96 metric tons, giving 504 metric tons for the combined thrust of the core and boosters. Now they list the same upper planetary stage, as used for Soyuz as having a thrust of 30 metric tons. The stage is powered by a single engine with four combustion chambers and nozzles. There is no clue as to how to reconcile the 534 metric tons of combined thrust in Soyuz with the 650 metric tons quoted for the same stages in the Voskhod of many years earlier. We still do not know what the seventh engine alluded to earlier meant, as only six can be counted.

The mystery of why the Soviet listed thrusts ran ahead of normal reality was finally solved in 1975. Maarten Houtman of Amsterdam was talking with a Soviet engineer at the Paris Air Show, and was told that the 600-metric ton figure for thrust was found by adding together the combined thrust of 4 RD-107 engines at 102 tons each, plus the RD-108 engine at 96 tons, for a total of 504 tons, and then adding to that the thrust of the same RD-108 which continued to burn after the 4 strap-ons dropped away, making the total of 600. The arithmetic is impeccable, but it seems a most peculiar way to count total thrust, and it still ignores the thrust of the final stage.

A review of the book by Leonid Vladimirov shows that he published in 1971 the thrusts of the Vostok (A-l) rocket 4 years ahead of the 1975 Soyuz disclosures on the same rocket, and he further had information that the mysterious upper stage had a thrust of 11 tons, which is consistent with the RD-119 engine.


Background Information
First Launch:
November 1963
Flight Rate:
45 per year (maximum recorded launch rate)
Launch Site:
Plesetsk, Russia; Baikonur, Kazakhstan
15,400 lb to LEO


  • Developed from the Vostok Launch Vehicle originally derived from the SS-6 ICBM
  • Incorporates upgraded second stage and avionics
  • Used to launch every former Soviet Union piloted spacecraft since 1964
  • Also used to launch photo reconnaissance satellites, earth resource satellites, and progress resupply missions to the Mir space station


  • Two-stage liquid fueled vehicle
  • Stage 1 core has one RD-108 booster engine (one turbopump with four separate combustion chambers) burning LO2/kerosene fed from stage 1 tanks, generating 167,000 lb of thrust
  • Stage 1 strap-ons each have one RD-107 engine (one turbopump with four separate combustion chambers) burning LO2/kerosene fed from stage 1 tank, generating a total of 740,000 lb of thrust
  • Stage 2 has one RD-461 engine burning LO2/kerosene, generating 67,000 lb of thrust


162 ft
Launch Weight:
639,000 lb
8.9 ft
Liftoff Thrust:
907,000 lb
Payload Fairing:
29.5 ft x 9.4 ft

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Page last modified: 02-04-2019 18:34:25 ZULU