An investigation was made of the effect of ionizing radiation on the burning rates and tensile strengths of various composite ammonium perchlorate propellants. The results of these studies demonstrated that, in many cases, drastic changes in burning rate and tensile strength occurred upon radiolysis. In order to elucidate the mechanism of these effects, a multi-pronged study of the effects of radiation on propellants and propellant components was initiated. This involved: (1) a study of the radiation induced decomposition of ammonium perchlorate with an elucidation of the various chemical species produced upon radiolysis and their yields (G values); (2) a study of radiation effects on burning rate by a technique in which the effect of radiation on each of the two components of a propellant, i. e., organic binder and inorganic oxidizer, is studied separately.