Manufacturer Name: MB-3. Designer: Rocketdyne. Developed in: 1957. Application: . Used on stages: Thor DM-21. Used on launch vehicles: Delta A, Delta B, Delta C, Thor Able-Star. Propellants: Lox/KeroseneThrust(vac): 77,564 kgf. Thrust(vac): 760.60 kN. Isp: 285 sec. Isp (sea level): 250 sec. Burn time: 164 sec. Mass Engine: 643 kg. Diameter: 2.4 m. Chambers: 1. Chamber Pressure: 40.00 bar. Area Ratio: 8.00. Thrust to Weight Ratio: 120.63. Country: USA. Status: Out of Production. First Flight: 1960. Last Flight: 1969. Flown: 47. Comments: Designed for booster applications. Gas generator, pump-fed.