Abstract: The uncertainties in aerodynamics and initial conditions are considered for assessing the robustness of the trajectory.The approach of assessing the robustness is the same algorithms used in designing the original auto landing trajectory,i.e.the method based on the 3 degrees-of-freedom nonlinear equations of motion which governing dynamic pressure.The energy potentialis defined as the measure of the ability to increase and decrease energy to remove energy dispersions.The touchdown characters,the allowable uncertainties in aerodynamics and dynamic pressure disturbance rejection are assessed when in the presence of uncertainties in aerodynamics.The result showsthat the trajectory is robust.