The RD-107 () and its sibling, the RD-108, are a type of

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 ...

used on the R-7 rocket family. RD-107 engines are used in each booster and the RD-108 is used in the central core. The engines have four main combustion chambers (each with a

nozzle A nozzle is a device designed to control the direction or characteristics of a fluid flow (specially to increase velocity) as it exits (or enters) an enclosed chamber or pipe (material), pipe. A nozzle is often a pipe or tube of varying cross ...

) and either two (RD-107) or four (RD-108) vernier chambers. The engines were first developed in the mid-1950s to launch the

R-7 Semyorka The R-7 Semyorka (, GRAU index: 8K71) was a Soviet Union, 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. A derivative, the R-7A Semyorka, R ...

, the 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 was later adapted into space

launch vehicle A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...

s and the engines have been improved over several generations. The most recent versions are the RD-107A and RD-108A engines are used to launch the

Soyuz-2 Soyuz2 (; GRAU index: 14A14) is a Russian expendable medium-lift launch vehicle and the seventh major iteration of the Soyuz rocket family. Compared to its predecessors, Soyuz-2 features significant upgrades, including improved engines and ...

, which is in active service .

Design

The RD-107 was designed under the direction of

Valentin Glushko Valentin Petrovich Glushko (; ; born 2 September 1908 – 10 January 1989) was a Soviet engineer who was program manager of the Soviet space program from 1974 until 1989. Glushko served as a main designer of rocket engines in the Soviet progra ...

at the Experimental Design Bureau (OKB-456) between 1954 and 1957. It uses

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 ...

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 " ...

as propellants operating in a

gas-generator cycle The gas-generator cycle, also referred to as the GG cycle or colloquially as an open cycle, is one of the most commonly used power cycles in bipropellant liquid rocket engines. Propellant is burned in a gas generator (analogous to, but distinct ...

. As was typical by all the descendants of the

V-2 rocket The V2 (), with the technical name ''Aggregat (rocket family), Aggregat-4'' (A4), was the world's first long-range missile guidance, guided ballistic missile. The missile, powered by a liquid-propellant rocket engine, was developed during the S ...

technology, the turbine is driven by steam generated by

catalytic Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst ...

decomposition of H₂O₂. The steam generator uses solid ''F-30-P-G'' catalyst. These are based on a variable sized pellet covered in an aqueous solution of

potassium permanganate Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, which dissolves in water as K+ and ions to give an intensely pink to purple solution. Potassium permanganate is widely us ...

and

sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...

. Each engine uses four fixed main combustion chambers. The RD-107 has an additional two vernier combustion chambers that can thrust vector in a single plane to supply attitude control. The RD-108 has four verniers to supply full vector control to the Blok-A stage. The single-axle

turbopump A turbopump is a fluid pump with two main components: a rotodynamic pump and a driving gas turbine, usually both mounted on the same shaft, or sometimes geared together. They were initially developed in Germany in the early 1940s. The most co ...

unit includes the steam driven turbine, an oxidizer pump, a fuel pump, and a nitrogen gas generator for tank pressurization. The RD-107 engines are used in each of the boosters of the

rocket, and a single RD-108 is used in the Blok-A stage (the central 1st stage). One important innovation of this engine was the capability to use variable mixture ratio between fuel and oxidizer. The natural variations in manufacturing between each engine meant that without an active propellant consumption control, each booster could deplete oxygen and fuel at a different rate. This might result in as much as tens of tonnes of unused propellant near the end of the burn. It would generate enormous stress on the structure and cause difficulties in steering due to the mass imbalance. The mixture ratio control system was developed to ensure the simultaneous consumption of propellant mass among the four R-7 boosters.

Production

The RD-107 and RD-108 engines are produced at the

JSC Kuznetsov JSC Kuznetsov () is one of the leading Russian producers of aircraft engines, liquid-propellant rocket engines as well as aeroderivative gas turbines and modular stations. The current joint-stock company was established through the consolidation ...

plant in

Samara, Russia Samara, formerly known as Kuybyshev (1935–1991), is the largest city and administrative centre of Samara Oblast in Russia. The city is located at the confluence of the Volga and the Samara rivers, with a population of over 1.14 million resident ...

, under the supervision of the Privolzhskiy branch of

NPO Energomash NPO Energomash "V. P. Glushko" is a major Russian rocket engine manufacturer. The company primarily develops and produces Liquid rocket engine, liquid propellant rocket engines. Energomash originates from the OKB, Soviet design bureau OKB-456, w ...

, also known as the

Volga The Volga (, ) is the longest river in Europe and the longest endorheic basin river in the world. Situated in Russia, it flows through Central Russia to Southern Russia and into the Caspian Sea. The Volga has a length of , and a catchment ...

branch. The Privolzhsky branch was organized as a branch of OKB-456 in 1958, specifically for the manufacture of RD-107 and RD-108 engines. The branch was led by Y.D. Solovjev until 1960, then by R.I. Zelenev until 1975, then by A.F. Udalov until 1978, and is currently led by A.A. Ganin.

Versions

Centre spatial guyanais - Rollout Soyuz 8842534152

RD-107 variants

Modifications to the RD-107 design have led to production of several distinct versions of the engine: * RD-107 (

GRAU index 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 ...

: 8D74): Original version. Used on ICBM versions of the R-7,

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 ...

, and

Vostok Vostok () refers to east in Russian but may also refer to: Spaceflight * Vostok programme, Soviet human spaceflight project * Vostok (spacecraft), a type of spacecraft built by the Soviet Union * Vostok (rocket family), family of rockets derived ...

rockets. * RD-107K (GRAU index: 8D74K): Improved version of the RD-107. Used on the Molniya, Vostok-2,

Vostok-2M The Vostok-2M (), GRAU index: 8A92M was an expendable launch system, expendable launch vehicle, carrier rocket used by the Soviet Union between 1964 and 1991. Ninety-three were launched, of which one failed. Another was destroyed before launch. I ...

, and Voskhod rockets. * RD-107MM (GRAU index: 8D728 or 8D74M): Increased thrust over the RD-107K by 5%. Used on the

Molniya-M The Molniya-M (, GRAU index: 8K78M) was a Soviet and Russian launch vehicle derived from the R-7 Semyorka Intercontinental ballistic missile (ICBM). The original 8K78 booster had been the product of a rushed development program and its launc ...

and

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 ...

universally adopted on R-7 vehicles in 1966. * RD-117 (GRAU index: 11D511): Improved structural changes. Used on the

Soyuz-U Soyuz-U ( GRAU index: 11A511U) was a Soviet and later Russian expendable medium-lift launch vehicle designed by the TsSKB design bureau and constructed at the Progress factory in Samara, Russia. The ''U'' designation stands for ''unified' ...

and Soyuz-U2 rockets. * RD-107А (GRAU index: 14D22): Improved version of the RD-117 with new injector design. Replaced 260 two-component centrifugal injectors with more than a thousand one-component injectors that provided finer aeration of propellant for more thorough burning, reducing high-frequency vibrations inside the combustion chambers and increasing

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

by about , or five percent. Used on the

Soyuz-FG The Soyuz-FG was an improved variant of the Soyuz-U launch vehicle from the R-7 (rocket family), R-7 rocket family, developed by the Progress Rocket Space Centre in Samara, Russia. It featured upgraded first and second stage engines, RD-107A and ...

, Soyuz-ST-A and Soyuz-ST-B rockets. * RD-107А (GRAU index: 14D22KhZ): Chemical ignited version of the RD-107A. Used on the Soyuz-2.1a and

Soyuz-2.1b Soyuz2 (; GRAU index: 14A14) is a Russian expendable medium-lift launch vehicle and the seventh major iteration of the Soyuz rocket family. Compared to its predecessors, Soyuz-2 features significant upgrades, including improved engines and ...

rockets.

RD-108 variants

Similar modifications have led to several distinct versions of the RD-108: * RD-108 (GRAU index: 8D75): Original version. Used on the R-7,

and Voskhod rockets. * RD-108K (GRAU index: 8D75K): Improved version of the RD-108. Used on the Molniya rocket. * RD-108MM (GRAU index: 8D727 or 8D75M): Increased thrust over the RD-108K by 5%. Used on the

and

rockets. * RD-118 (GRAU index: 11D512): Improved structural changes. Used on the

rocket. * RD-118PF (GRAU index: 11D512PF): Variant of the RD-118 optimized to run on

Syntin Syntin is a hydrocarbon with the molecular formula C10H16 used as a rocket fuel. It is a mixture of four Stereoisomerism, stereoisomers (see below). It has a density of 0.851 g/mL, and a boiling point of 158 °C. Due to the presence of thre ...

fuel rather than RG-1. It used selected injectors to minimize instabilities without changing constructions methods, but it required a significant number of engines produced to get injectors that complied with the stringent specifications. Used on the Soyuz-U2 rocket. * RD-108A (GRAU index: 14D21): Improved version of the RD-118 with new injector design. Replaced 260 two-component centrifugal injectors with more than a thousand one-component injectors that provided finer aeration of propellant for more thorough burning, reducing high-frequency vibrations inside the combustion chambers and increasing

by about , or five percent. Used on the

, Soyuz-ST-A and Soyuz-ST-B rockets. * RD-108A (GRAU index: 14D21KhZ): Chemical ignited variant of the RD-108A. Used on the Soyuz-2.1a and

rockets. Work on the 14D21 and 14D22 engines started in 1986, with a preliminary design completed in 1993. These engines incorporate a new injector head design to increase

. The first launch of a

Progress Progress is movement towards a perceived refined, improved, or otherwise desired state. It is central to the philosophy of progressivism, which interprets progress as the set of advancements in technology, science, and social organization effic ...

cargo spacecraft using a launch vehicle equipped with these engines took place in May 2001. The first

human spaceflight Human spaceflight (also referred to as manned spaceflight or crewed spaceflight) is spaceflight with a crew or passengers aboard a spacecraft, often with the spacecraft being operated directly by the onboard human crew. Spacecraft can also be ...

launch utilizing these engines took place in October 2002.

References

External links

ЖРД РД-107 и РД-108 и их модификации

РД-107/108 на сайте НПО Энергомаш
{{Russian and Soviet military designation sequences Rocket engines of Russia Rocket engines of the Soviet Union Rocket engines using kerosene propellant Rocket engines using the gas-generator cycle Energomash rocket engines