Abstract: A monopropellant rocket engine in which nitrous oxide is the propellant includes a catalyst bed on an end of a diverging combustion chamber to inject a first flow of monopropellant to ignite the monopropellant, followed by a series of additional monopropellant injections along the diverging combustion chamber where the previously injected monopropellant decomposes to be used to ignite the downstream injected monopropellant. When all monopropellant has been decomposed, the monopropellant is passed through a throat and nozzle to produce thrust. A control valve is used to regulate an amount of monopropellant injected at each point in order to regulate an amount of thrust.