RD-107

The RD-107 was designed under the direction of Valentin Glushko at the Experimental Design Bureau (OKB-456) between 1954 and 1957. It uses liquid oxygen and highly refined kerosene (RG-1) as propellants operating in a gas-generator cycle. As was typical by all the descendants of the V-2 rocket technology, the turbine is driven by steam generated by catalytic decomposition of H2O2. The steam generator uses solid F-30-P-G catalyst. This consists of variable-sized porous oxidized iron pellets, half of which are coated in a mixture of potassium permanganate and sodium. 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 unit includes the steam driven turbine, an oxidizer pump, a fuel pump, and a nitrogen gas generator for tank pressurization. == Production ==

The RD-107 and RD-108 engines are produced at the JSC Kuznetsov plant in Samara, Russia, under the supervision of the Privolzhskiy branch of NPO Energomash, also known as the Volga branch. == Versions ==

RD-107 variants Modifications to the RD-107 design have led to production of several distinct versions of the engine: • RD-107 (GRAU index: 8D74): Original version. Used on ICBM versions of the R-7, Sputnik, Luna, and Vostok rockets. • RD-107K (GRAU index: 8D74K): Improved version of the RD-107. Used on the Molniya, Vostok-2, Vostok-2M, and Voskhod rockets. • RD-107MM (GRAU index: 8D728 or 8D74M): Increased thrust over the RD-107K by 5%. Used on the Molniya-M and Soyuz universally adopted on R-7 vehicles in 1966. • RD-117 (GRAU index: 11D511): Improved structural changes. Used on the Soyuz-U 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 by about , or five percent. Used on the Soyuz-FG, 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 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, Sputnik, Vostok 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 Molniya-M and Soyuz rockets. • RD-118 (GRAU index: 11D512): Improved structural changes. Used on the Soyuz-U rocket. • RD-118PF (GRAU index: 11D512PF): Variant of the RD-118 optimized to run on Syntin 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 specific impulse by about , or five percent. Used on the Soyuz-FG, 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 Soyuz-2.1b 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 specific impulse. The first launch of a Progress cargo spacecraft using a launch vehicle equipped with these engines took place in May 2001. The first human spaceflight launch utilizing these engines took place in October 2002. ==See also==