Government Designation: 8D43. Designer: Kosberg. Application: UR-500 stage 1 original concept. Used on launch vehicles: Monoblock UR-500, Polyblock UR-500. Used on spacecraft: Monoblock UR-500, Polyblock UR-500. Propellants: N2O4/UDMHThrust(vac): 57,000 kgf. Thrust(vac): 559.00 kN. Isp: 316 sec. Isp (sea level): 284 sec. Burn time: 115 sec. Chambers: 1. Chamber Pressure: 147.00 bar. Area Ratio: 28.50. Oxidizer to Fuel Ratio: 2.60. Country: Russia. Status: Hardware. References: 273 , 320 . Comments: Low-expansion ratio gimballed variant developed for UR-500. In initial configuration 4 would be clustered with 4 x Glushko 11D43. Abandoned in favor of 6 x Glushko 11D48. Further developed into the RD-0208 and RD-0210 engines.