Autonomous aerospace launchers must carry out their missions safely because any accident can lead to important or dramatic consequences. It is essential to develop robust control solutions that guarantee optimal performances even when failures occur during these missions. The main objective of this paper is to present the development of a faulttolerant control design in the case of an aerospace launcher. The method consists of defining and carrying out effective procedures for early detection of some critical situations and providing an adequate control that maintains the safe behaviour of the launcher. The improved control performance is obtained by using a sliding mode observer for a robust reconstruction of an actuator fault. This reconstruction is used then to generate an added signal in the initial control law that compensates for the effect of the faults. Simulation results will show the efficiency of the proposed method.