This paper presents design analysis of impulse thrusters intended for guidance and control systems of missiles. Impulse thrusters are small solid propellant, short-operation, high thrust rocket motors. They are mounted laterally on the missile's control block, and are used to generate control forces to adjust its trajectory. To minimize the control block weight and achieve better missile performances, aluminum alloy is utilized, due to its favorable strength-to-weight ratio and ease of manufacturing productivity. However, the sensitivity of aluminum alloys to high temperatures necessitates a comprehensive thermal analysis, to ensure structural integrity and performance reliability under operational conditions. For that, three impulse thruster models are designed with incrementally higher thrust and thermal loading. An internal ballistic model is employed to predict their performances, with results validated through static experimental tests. Then, numerical CFD and heat transfer simulations are conducted, to predict eventual thruster block structure overheating, to achieve the maximum possible performances. The study highlights the importance of material selection, thermal analysis, and propellant design for optimizing impulse thruster performance and ensuring the reliability of control systems of missiles.