Hybrid rockets are promising propulsion systems with wide margins for yet unexplored development. In order to fully exploit the potential of these systems, the consideration of a hybrid fuel combining a solid grain and a liquid oxidizer is being examined. To achieve a fuel with low environmental impact and maximized performance, a Multidisciplinary Design Optimization (MDO) problem needs to be formulated. This involves the development of a MDO framework specifically for optimizing the solid grain, taking into consideration additive manufacturing constraints and utilizing a propulsion model to predict the specific impulse generated. Ultimately, a multi-objective function is established, combining both structural and performance goals.