Solid Rocket Propellant is one variety of the fuel that drives rockets skyward. Burning at more than 2,000 degrees Celsius, it is a complex, highly energetic and precise chemical mixture that can be cast in a variety of shapes and sizes. When a special formula containing an oxidiser and a fuel are combined, a highly combustible reaction creates the thrust to launch the fastest and most complex machines ever built.
See https://www.amgc.org.au/project/ammonium-perchlorate-sovereign-manufacturing/