spacecraft and or 2 propellant settling attitude and roll control of missiles launchers and space planes application_number US 201414892033 A description the inventive oxidizer rich monopropellant comprises 70 90 of adn or han 0 10 ammonia and balance water according to the present invention the inventive oxidizer rich monopropellant is used for further combusting in a second reaction stage fuel rich gasses obtained from combustion of a fuel rich monopropellant such as a conventional adn based or han based liquid monopropellant the inventive liquid oxidizer rich monopropellant is thus intended for use in bipropellant operation in a chemical rocket engine together with the fuel rich liquid monopropellant as illustrated in fig1 a suitable engine capable of operating in bipropellant mode may comprise a primary reaction chamber 130 for a fuel rich monopropellant and a secondary reaction chamber 150 for the decomposition of the inventive oxidizer rich propellant wherein the primary reaction chamber is connected to the secondary reaction chamber so that fuel rich gas from the decomposition of the fuel rich oxidizer in the primary reaction chamber can flow into the second reaction chamber the inventive oxidizer rich monopropellant is injected into the secondary reaction chamber 150 via means for injection 125 e g an injector in such engine the catalyst in the primary reaction chamber would be the life limiting element of the thruster when exposed to the reactive decomposition and combustion species and operated at higher temperatures than their current design limits by injecting the oxidiser.