The unsteady aerodynamics of a candidate delta-wing shuttle orbiter have been investigated. Three potentially dangerous flow separation phenomena involving the delta wing have been identified, each of which could seriously compromise the flight dynamics. They are 1) leeside shock-induced separation, 2) sudden leading-edge stall, and 3) the subsonic leading-edge vortex and vortex burst. Each of these unsteady flow phenomena can be triggered by control surface deflection. Furthermore, wing stall and control-induced separation effects interact with the relatively large fuselage, increasing the coupling between lateral and directional stability characteristics. Trajectory shaping may be the most powerful means of dealing with these flow separation effects. The re-entry trajectory can be tailored to avoid or quickly traverse the unstable flow regions. However, it is prudent to use available means to control the duration and extent of separated flow when traversing the critical flow region. The unstable flow boundaries may be altered by modification of the wing planform, airfoil section, control deflections, etc.