The increasing complexity of modern space missions, combined with stringent requirements on pointing accuracy, agility, and fault tolerance, has made attitude control a critical aspect of spacecraft design. The growing use of small and agile satellites further amplifies the need for control strategies that are both efficient and robust to actuator limitations and failures. Modern space missions increasingly require spacecraft to perform agile maneuvers and high-precision pointing while ensuring reliability and robustness of onboard subsystems. In this context, attitude determination and control play a fundamental role in mission success. To meet these requirements, spacecraft attitude control is implemented through the Attitude Control System (ACS) which includes sensors, actuators, and control algorithms.