RD107108

RD-107 and RD-108 are a pair of Soviet liquid-fueled rocket engines developed for the R-7 Semyorka family of launch vehicles. The RD-107 powered the four strap-on boosters, while the RD-108 was used on the central core stage. They were among the earliest engines designed for the R-7 lineage and served as foundational components for many early and mid-century Soviet space launches.

Both engines burn liquid oxygen and refined kerosene and were built around a gas-generator cycle. Each engine employs a single combustion chamber with a single nozzle and is equipped with thrust-vector control through engine gimbaling, enabling control of the launch vehicle's attitude during ascent.

Variants and legacy: The baseline RD-107 and RD-108 were later upgraded to RD-107A and RD-108A, which offered improvements in performance and reliability. These engines powered numerous R-7 family missions and contributed to the operational success of a range of vehicles, including early Vostok and Voskhod configurations and later Soyuz launchers.

Impact and reception: The RD-107/108 pair played a crucial role in the development of the Soviet launch vehicle program and helped establish a robust design approach for large LOX/kerosene engines in the R-7 family. Their evolution and successful deployment influenced subsequent generations of Russian engines and the enduring Soyuz launch vehicle lineage.