a solid or semisolid propellant comprising grains of propellant or propellant components bonded together so as to create voids within the propellant volume , said grains bonded together with sufficient strength to substantially delay the fluidization of the propellant by the onset of taylor unstable burning , said propellant having a rapid burn rate below that associated with taylor unstable burn . in another embodiment , the grains are held within and the voids are filled with viscous fluid binder such as a petroleum oil , said binder functioning to hinder taylor unsatable burning and yet permit very rapid burning within the propellant volume .