Development of the Algol III Solid Rocket Motor for Scout

The Algol III is a new high-performance solid rocket motor developed for use as the first stage of the NASA SCOUT-D and -E launch vehicles. The motor delivers a 30% gain in total impulse over its predecessor and provides a 35-45% gain in payload mass capability at a fractional increase in cost. Algol III has successfully completed development and qualification at United Technology Center under contract to LTV Aerospace Corp.'s Vought Missiles and Space Co., the SCOUT prime contractor for the NASA Langley Research Center. During this two-year program, two development and three qualification motors were successfully static-tested. The motor is 45 in. in diameter, has a length-to-diameter ratio of 8:1, and delivers an average of 100,000 lb of thrust for an action time of 72 sec. The motor design features a very high volumetrically loaded internal-burning-charge design of 17% aluminized composite polybutadiene propellant, a plasma-welded and heat-treated 4130 steel alloy case, and an all-ablative plastic nozzle liner enclosed in a steel shell. The only significant development problem encountered was tailoring the grain design to account for erosive burning effects produced in the high length-to-diameter ratio, high subsonic mach number port. In this paper, the program development results will be presented, together with design descriptions and fabrication methods for each of the major components.