This paper studies and addresses the issue of time efficient large angle maneuver for a rigid spacecraft using single gimbal control momentum gyroscope (SGCMG) in the presence of external disturbances. A real time closed loop control based on the Legendre-pseudospectral method and sliding mode method is utilized to fulfill the mission. An integral function consisting of the square of the SGCMG gimbal velocity magnitude and time is chosen as the cost function. With the help of Legendre-pseudospectral method, the optimal control problem is converted to a nonlinear programming problem, and the optimal solution is derived which contains the desired path to guide the satellite attitude maneuver. The sliding mode method is adopted in the design of the attitude controller to track accurately the desired path comprised of the satellite attitude quaternion and velocity. Simulation results prove the robustness and time efficiency of the derived controller as well as its ability to avert SGCMG singularity.