Gross Mass: 378,900 kg.
Empty Mass: 26,900 kg. Thrust (vac): 916,700 kgf. Isp: 310 sec. Burn time: 119 sec. Propellants: N2O4/UDMHIsp(sl): 280 sec. Diameter: 4.1 m. Span: 7.4 m. Length: 21.2 m. Country: USSR. No Engines: 4. 8D43 + 11D43Status: Study 1962. Comments: Original 'Polyblock' design for Proton first stage. This was selected configuration; although somewhat greater in dry mass, it had the advantages of shorter length.