RD-107

The RD-107 (Russian: Ракетный Двигатель-107, romanized: Raketnyy Dvigatel-107, lit. 'Rocket Engine 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. An unusual feature of these engines is the turbines, driven by the catalytic decomposition of H2O2.