Ammonium nitrate as an oxidizer in solid composite propellants

Despite the fact that ammonium nitrate (AN) has the highesthydrogen content and fairly high oxygen balance (compared to other oxidizers), its extremelylowformationenthalpyandrelativelylowdensitymakesit one of the worst power oxidizers in solid composite propellants (SCP). Nevertheless, AN has certainadvantages i the combustion of the compositions containing AN is virtually safe, its combustion products are ecologically clean, it is very accessible and cheap, and also very thermostable(farmorestablethanammoniumdinitramide(ADN)).Besides, itslowdensitystopsbeingadisadvantageifthepropellanthastobeused indeepspaceandtherefore,mustbecarriedtherewithotherrocketcarriers. The low cost of AN may also become a serious advantage in the AN application even in lower stages of multistage space launchers as well as in one-stage space launchers with low mass fraction of the propellant. The mainspeci¦c features relevantto the creationof AN-based SCPs with the optimal energetic characteristics are discussed. The use ofmetalsandtheirhydridesandproperfuel-bindersaswellastherecent successes in phase stabilization of AN are described.