AIR PRESSURE over a Lockheed S-3A airplane in flight is highest near the craft's nose and inside the engine nacelles, which are below the wings. The grid visible on the surface of the image to the left is the computational mesh; a value of the air pressure was computed for each point at which grid lines intersect. Such simulations are critical means of verifying designs for supersonic and hypersonic (below right) aircraft, for which wind-tunnel testing is impossible. The simulation of this supersonic aircraft design also shows the sonic boom, visible as a circle behind the vehicle. Such booms are a major issue in ongoing studies of whether the public will accept these aircraft.