Propellant system for solid fuel rocket

An oxidizer package for use in a solid fuel propellant system. The oxidizer package comprises a solid oxidizer in the form of discrete pellets of predetermined geometric shape. The pellets are arranged in an array with spaces amongst the pellets. A holder is provided for maintaining the pellets in the array for receipt of a binder introduced to spaces amongst the array of pellets. Preferred propellants include hydrazinium nitroformate and nitronium perchlorate. This arrangement for the pellets can achieve loadings as high as 85 % by weight for the pellets.