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Castor 120

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AKA: SR118. Status: Out of production. Number: 18 . Thrust: 1,650.00 kN (370,930 lbf). Gross mass: 53,118 kg (117,105 lb). Unfuelled mass: 4,086 kg (9,008 lb). Specific impulse: 280 s. Specific impulse sea level: 229 s. Burn time: 81 s. Height: 9.02 m (29.59 ft). Diameter: 2.36 m (7.74 ft).

A motor similar in size to the Peacekeeper missile stage 1 motor. It fills the gap between Castor 4A and the large segmented motors. Unit cost would be about $3.5 million for volume production, rising to $7.5 million for one annually. Further applications include using it as a strap-on for launchers, such as Delta. It can be used in a stage 1 or 2 strap-on since the forward and aft ends can take tension and compression forces. A (5.5 degree thrust vector control is provided by a movable nozzle. The grain can be changed (tailored) by adding aft slots to reduce thrust during maximum-q, and by adding forward slots for high initial thrust.. First Flight. November 1994. Propellant Type: TP-H1246 HTPB, 19% Al, and 69% AP. Propellant Shape: three machined aft conical slots with formed forward slot. Propellant Mass Fraction: 0.923 (49,032 kg). Burn Time: 81 sec.. Thrust: 1650 kN vacuum average. Isp: 280.1 sec vacuum. Total Impulse: 133,440 kNs vacuum. Pressure: 101 atm maximum and 78 atm average. Nozzle Throat Diameter: 368 mm. Nozzle Length: 1448 mm. Nozzle Exit Diameter: 1600 mm. Nozzle Materials: glass epoxy and polyisoprene flex bearing. 3D carbon-carbon throat. carbon phenolic exit cone. aluminum stationary shell. steel throat support. Casing Materials: carbon epoxy, lined with silica-filled EPDM rubber EPM.

Thrust (sl): 1,313.900 kN (295,376 lbf). Thrust (sl): 133,987 kgf. Chamber Pressure: 79.00 bar. Area Ratio: 24. Propellant Formulation: HTPB.