NPO Energomash
The RD-120 (GRAU Index 11D123) is a liquid upper stage rocket engine burning RG-1 (refined kerosene) and LOX in an oxidizer rich staged combustion cycle with an O/F ratio of 2.6. It is used in the second stage of the Zenit family of launch vehicles. It has a single, fixed combustion chamber and thus on the Zenit it is paired with the RD-8 vernier engine. The engine has been developed from 1976 to 1985 by NPO Energomash with V.P. Radovsky leading the development. It is manufactured by, among others, Yuzhmash in Ukraine.