Engine Model: OMV Variable Thrust Engine. Designer: TRW. Propellants: N2O4/MMH. Thrust(vac): 578 N (129 lbf). Burn time: 2,800 sec. Mass Engine: 6.80 kg (14.90 lb). Diameter: 2.71 m (8.90 ft). Length: 0.70 m (2.30 ft). Chambers: 1. Chamber Pressure: 6.90 bar. Area Ratio: 125.00. Thrust to Weight Ratio: 8.52. Country: USA. Status: In Production. Dry Mass: 6.8 kg. Length: 70.05 cm. Maximum Diameter: 27.13 cm. Mounting: fixed. Engine Cycle: pressure fed. Oxidizer: di-nitrogen tetraoxide at 0.119 kg/sec during maximum Thrust: . Fuel: MMH at 0.0745 kg/sec during maximum Thrust. O/F Ratio 1.64. Thrust: 57.8-578 N in vacuum, with a throttle range ratio of 10:1. Isp: 280-308 sec in vacuum. Expansion Ratio: 125:1. Cooling Method: radiative cooling. Chamber Pressure: 0.75-6.8 atm. Ignition: hypergolic. Burn Time: 28 hours total with a 2800 sec maximum single burn.