The Control of Dynamical System is a subject at the boundary between engineering and applied mathematics. Any satellite put into orbit requires an adequate attitude control system, whether it is for scientific observations, telecommunications or any other service. Over the years, a growing number of powerful, responsive and accurate actuators have been developed, such as thrusters, Control Moment Gyroscopes (CMGs) and reaction wheels. Meanwhile, new control algorithms have been studied, of which the Sliding Mode Controller (SMC) is one of the most popular. For many applications requiring very precise control, an active full three-axis control is used: in this case, the satellite is stabilized by the above mentioned actuators.