Engine Model: Star 20. Manufacturer Name: TE-M-640-1. Government Designation: Altair 3. Other Designations: 27.5-KS-6,100. Designer: Thiokol. Gross Mass: 301 kg (663 lb). Empty Mass: 28 kg (61 lb). Propellants: Solid. Thrust(vac): 27.135 kN (6,100 lbf). Isp: 287 sec. Burn time: 28 sec. Diameter: 0.50 m (1.64 ft). Chambers: 1. Country: USA. Status: In Production. Flown: 39. Altair III was developed as the propulsion unit for the fourth stage of the Scout launch vehicle. A filament-wound, fiberglass-epoxy case contains the CTPB propellant grain. The lightweight, external nozzle is a composite of graphite, plastic, and steel. The consumable pyrogen igniter is actuated by two 6-second-delay electrical initiators or two SBASI zero-time-delay initiators. Total impulse 78,670 kgf-s. Propellant mass fraction 0.908.
