Determination of the grain geometry is an important and critical step in the design of solid propellant rocket motors. Because, the performance of the rocket is greatly effect by the burning surface area of the solid propellant. The performance prediction of the solid rocket motor can be achieved easily if the burn back steps of the grain are known. In this study, grain burn back analysis for 3-D star grain geometries was investigated. The method used was solid modeling (ANSYS(r) - DM, PRO-E and GAMBIT) of the propellant grain for predefined intervals of burn back. In this method, the initial...