If memory serves me, the solid fuel boosters on the Shuttle were comprised of a mixture of powdered aluminum, ammonium perchlorate (oxidizer), iron oxide, and an epoxy binder. The final result was a product about the consistency of a pencil eraser; this semi-soft quality is important because the way solids work, with… » 9/16/13 10:11am 9/16/13 10:11am