Starting in January 2025, I joined a research group focusing on the development of Solid Rocket Motors. Our primary focus was to create 2 custom independent propellant formulas that are optimized for special tasks for our final project, a 2-stage student built rocket designed to surpass the Karman Line (over 330,000 ft).
Both formulas, AST1 and AST2, have special characteristics that make them unique. AST1, the booster propellant, is designed to burn efficiently and quickly. It's primary goal is to get the heavy 160lb+ rocket off the pad, and to a reasonable velocity past 30,000+ ft.
On the other hand, the sustainer propellant, AST2, is designed to burn very slowly. This allows the motor to burn at higher altitudes with lower air density, allowing for a higher velocity final altitude.