The RD-107 and its sibling, the RD-108, are a type of rocket engine 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) 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 first intercontinental ballistic missile. The R-7 was later adapted into space launch vehicles 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, which is in active service as of 2024.
Design
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