The S5.98M, also known as the 14D30, is a Russian rocket engine, currently powering the Briz upper stages. It was designed by KB KhIMMASH, the famous Isaev designed bureau. It burns a hypergolic mixture of unsymmetrical dimethylhydrazine (UDMH) fuel with dinitrogen tetroxide (N2O4) oxidizer in a gas-generator cycle.
See also Briz-M - The upper stage that is powered by the S5.98M. Proton-M - The heavy lift rocket that uses the Briz-M stage. Rokot - The light lift rocket that uses the smaller Briz-KM stage. Khrunichev - The manufacturer of the Briz stage and the corporate parent of the designer bureau.
References
External links KB KhIMMASH Official Page (Russian, Archived) Khrunichev Official Page (Archived) ILS Briz-M Page, the commercial launcher of the Proton-M Eurockot Official Page, the commercial launcher of the Rokot