ABSTRACTIn this paper, a non-linear tracking control algorithm is extended. The control objective of this research is to track a desired time-varying attitude of a satellite in the presence of inertia uncertainties and external disturbances, in order to be more suitable for implementation in a real-world application. In this investigation, the actuators are reaction wheels and the actuator dynamics are modelled in addition to the spacecraft dynamics. Thus, the control signal is DC motor voltage which is the most fundamental control variable and can be generated easily by a motor driver in practical cases. To achieve robust tracking of the desired time-varying attitude, a sliding mode controller is designed, and adaptive techniques are developed based on sliding mode control to overcome the inertia uncertainties and to estimate and compensate external disturbances. The kinematic equations of the satellite are expressed using quaternion parameters, and a novel control law will be derived by using a new facilitating approach in controller design, which is based on quaternion algebra, because of quaternion advantages, such as singularity rejection. Using this approach it will be more comfortable to deal with tedious mathematical operations, and on contrary with most of the previous studies, the terms corresponding to derivatives of the desired attitude are not neglected, and tracking capability is retained. The global stability of both methods (Sliding Mode Control (SMC) and adaptive sliding) is investigated using Lyapunov’s stability theorem. In order to validate the control methods, first, Simulink-ADAMS co-simulation of a 3-DOF attitude control is used to verify the algorithm performance and integrity, and finally, the control strategy is implemented on the Amirkabir University of Technology (AUT) 3-DOF attitude simulator for different types of non-linear attitudes. Both co-simulation and implementation results clearly illustrate the designed attitude control algorithm’s excellent performance in the various manoeuvres.