Engine Model: KTDU-5A. Manufacturer Name: KTDU-5A. Other Designations: S5.5, S5.5A. Designer: Isayev. Application: Luna E-6, Luna E-6LF, Luna E-6LS, Luna E-6M, Luna E-6S. Propellants: Nitric acid/Amine. Thrust(vac): 45.500 kN (10,229 lbf). Isp: 287 sec. Isp (sea level): 117 sec. Burn time: 43 sec. Mass Engine: 48 kg (105 lb). Diameter: 1.70 m (5.50 ft). Length: 1.91 m (6.26 ft). Chambers: 1 + 3. Chamber Pressure: 62.80 bar. Area Ratio: 43.40. Oxidizer to Fuel Ratio: 3.60. Thrust to Weight Ratio: 50.47. Country: Russia. Status: Out of Production. 1st turbopump engine with surface tension propellant management devices in tanks, allowing re-ignition in Zero-G. 3 fixed steering thrusters using the turbine exhaust gas for attitude control. Thrusts 45,5 + 0,245 kN. System mass 138,2 kg incl. tanks.