text: Uses Ammonium perchlorate composite propellant is typically for aerospace rocket propulsion where simplicity and reliability are desired and specific impulses (depending on the composition and operating pressure) of  are adequate. Because of these performance attributes, APCP has been used in the Space Shuttle Solid Rocket Boosters, aircraft ejection seats, and specialty space exploration applications such as NASA's Mars Exploration Rover descent stage retrorockets. In addition, the high-power rocketry community regularly uses APCP in the form of commercially available propellant "reloads", as well as single-use motors. Experienced experimental and amateur rocketeers also often work with APCP, processing the APCP themselves.
  Composition
  Overview
  Ammonium perchlorate composite propellant is a composite propellant, meaning that it has both fuel and oxidizer combined into a homogeneous mixture, in this case with a rubbery binder as part of the fuel. The propellant is most often composed of ammonium perchlorate (AP), an elastomer binder such as hydroxyl-terminated polybutadiene (HTPB) or polybutadiene acrylic acid acrylonitrile prepolymer (PBAN), powdered metal (typically aluminium), and various burn rate catalysts. In addition, curing additives induce elastomer binder cross-linking to solidify the propellant before use. The perchlorate serves as the oxidizer, while the binder and aluminium serve as the fuel. Burn rate catalysts determine how quickly the mixture burns. The resulting cured propellant is fairly elastic (rubbery), which also helps limit fracturing during accumulated damage (such as shipping, installing, cutting) and high acceleration applications such as hobby or military rocketry. This includes the Space Shuttle missions, in which APCP was used for the two SRBs.