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

rocket engine A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accorda ...

initially used to launch

R-7 Semyorka The R-7 Semyorka (russian: link=no, Р-7 Семёрка), officially the GRAU index 8K71, 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 1 ...

missiles. RD-107 engines were later used on space

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and sys ...

s based on the R-7. , very similar RD-107A and RD-108A engines are used to launch the

Soyuz-2.1a Soyuz-2 ( GRAU index 14A14) is a modernized version of the Soviet Soyuz rocket. In its basic form, it is a three-stage launch vehicle for placing payloads into low Earth orbit. Compared to the previous versions of the Soyuz, the first-stag ...

, and Soyuz-2.1b, which are in active service.

Design

The RD-107 was designed under the direction of

Valentin Glushko Valentin Petrovich Glushko (russian: Валенти́н Петро́вич Глушко́; uk, Валентин Петрович Глушко, Valentyn Petrovych Hlushko; born 2 September 1908 – 10 January 1989) was a Soviet engineer and the m ...

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

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an app ...

and

kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning " wax", and was re ...

as propellants operating in a

gas generator A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical. The term often refers to a device that uses a ...

cycle. As was typical by all the descendants of the

V-2 rocket The V-2 (german: Vergeltungswaffe 2, lit=Retaliation Weapon 2), with the technical name ''Aggregat 4'' (A-4), was the world’s first long-range guided ballistic missile. The missile, powered by a liquid-propellant rocket engine, was develop ...

technology, the turbine is driven by steam generated by

catalytic Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

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, that dissolves in water as K+ and , an intensely pink to purple solution. Potassium permanganate is widely used in the c ...

and

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

. 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 of such vernier combustion chambers to supply full vector control to the Blok-A stage. The single-axle

turbopump A turbopump is a propellant 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 purpo ...

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

Soyuz-2 Soyuz-2 ( GRAU index 14A14) is a modernized version of the Soviet Soyuz rocket. In its basic form, it is a three-stage launch vehicle for placing payloads into low Earth orbit. Compared to the previous versions of the Soyuz, the first-stage ...

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 boosters would deplete oxygen and fuel at different rates. This might result in as much as tens of tonnes of unburned propellant near the end of the burn. It would generate enormous strains on the structure and control authority due to the mass imbalance. Thus, 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 plant in

Samara, Russia Samara ( rus, Сама́ра, p=sɐˈmarə), known from 1935 to 1991 as Kuybyshev (; ), is the largest city and administrative centre of Samara Oblast. The city is located at the confluence of the Volga and the Samara rivers, with a population ...

, 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 propellant rocket engines. Energomash originates from the Soviet design bureau OKB-456, which was founded in 1 ...

, also known as the

Volga The Volga (; russian: Во́лга, a=Ru-Волга.ogg, p=ˈvoɫɡə) is the longest river in Europe. Situated in Russia, it flows through Central Russia to Southern Russia and into the Caspian Sea. The Volga has a length of , and a catch ...

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

RD-107 variants

Modifications to the RD-107 design have led to production of several distinct versions of the engine: * RD-107 (AKA 8D74): Original version. Used on the R-7,

Sputnik Sputnik 1 (; see § Etymology) 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. It sent a radio signal back to Earth for ...

, Vostok and Voskhod. * RD-107K (AKA 8D74K): Improved version of the 8D74. Used on the Molniya (8К78). * RD-107ММ (AKA 8D728 or 8D74M): Increased thrust over the 8D74K by 5%. Used on the

Molniya-M The Molniya-M (russian: Молния, meaning "lightning"), designation 8K78M, was a Soviet Union (later Russian) launch vehicle derived from the R-7 Semyorka Intercontinental ballistic missile (ICBM). The original 8K78 booster had been the ...

(8К78М) and

Soyuz Soyuz is a transliteration of the Cyrillic text Союз ( Russian and Ukrainian, 'Union'). It can refer to any union, such as a trade union (''profsoyuz'') or the Union of Soviet Socialist Republics (Сою́з Сове́тских Социалис ...

(11A511). * RD-117 (AKA 11D511): Improved structural changes. Used on the

Soyuz-U The Soyuz-U launch vehicle was an improved version of the original Soyuz rocket. Soyuz-U was 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 cons ...

(11А511U) and

Soyuz-U2 The Soyuz-U2 ( GRAU index 11A511U2) was a Soviet, later Russian, carrier rocket. It was derived from the Soyuz-U, and a member of the R-7 family of rockets. It featured increased performance compared with the baseline Soyuz-U, due to the use ...

(11A511U2). * RD-107А (AKA 14D22): Improved version of the 11D511 with new injector design that eliminated the high frequency combustion instabilities. Used on the

Soyuz-FG The Soyuz-FG launch vehicle was an improved version of the Soyuz-U from the R-7 family of rockets, designed and constructed by TsSKB-Progress in Samara, Russia. Guidance, navigation, and control system was developed and manufactured by "Polis ...

(11А511U-FG), Soyuz-STA (372RN21A) and Soyuz-STB (372RN21B). * RD-107А (AKA 14D22KhZ): Chemical ignited version of the 14D22. Used on the

(14A14-1A) and Soyuz-2.1b (14A14-1B).

RD-108 variants

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

, Vostok and Voskhod. * RD-108K (AKA 8D75K): Improved version of the 8D74. Used on the Molniya (8К78). * RD-108ММ (AKA 8D727 or 8D75M): Increased thrust over the 8D74K by 5%. Used on the

(8К78М) and

(11A511). * RD-118 (AKA 11D512): Improved structural changes. Used on the

(11А511U). * RD-118PF (AKA 11D512PF): Version of the 11D5212 that run on

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

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

(11A511U2). * RD-108А (AKA 14D21): Improved version of the 11D511 with new injector design that eliminated the high frequency combustion instabilities. Used on the

(11А511U-FG), Soyuz-STA (372RN21A) and Soyuz-STB (372RN21B). * RD-108А (AKA 14D21KhZ): Chemical ignited version of the 14D22. Used on the

(14A14-1A) and Soyuz-2.1b (14A14-1B). 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

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine (a rocket using propellant or a jet engine using fuel) creates thrust. For engines whose reaction mass is only the fuel they carry, specific impulse is ...

. The first launch of a

Progress Progress is the movement towards a refined, improved, or otherwise desired state. In the context of progressivism, it refers to the proposition that advancements in technology, science, and social organization have resulted, and by extension w ...

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.

Hypergolic vs. pyrotechnic ignition

Currently produced engines are ignited with a

pyrotechnic Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. ...

ignition system. Energomash reports a new,

hypergol A hypergolic propellant is a rocket propellant combination used in a rocket engine, whose components spontaneously ignite when they come into contact with each other. The two propellant components usually consist of a fuel and an oxidizer. The ...

ic ignition system (on engines designated 14D21KhZ and 14D22KhZ) are ready for certification and flight tests.

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