What causes the two sonic booms as the shuttle is approaching the landing site?
As the space shuttle re-enters the atmosphere at supersonic speeds, it creates shock waves that produce sonic booms. There is a shock wave at the orbiter’s nose and one at the orbiter’s tail as it re-enters These shock waves are created when the pressure disturbances caused by the shuttle flying through the air cannot escape the shuttle. These pressure waves travel at the speed of sound, but the shuttle is flying faster than the speed of sound, so a wave of pressure builds up along the nose and tail. As the shuttle altitude decreases, these pressure waves intersect the ground with a large pressure delta that your ears detect as a boom. In fact, you’ll hear not one, but two sonic booms! Because the space shuttle is so large, 37 meters (122 feet) long, you will hear the sonic booms created by both the nose and tail shock waves, which occur about one-half second apart. All supersonic airplanes produce two sonic booms, but because they happen so close to each other, you hear them as one so
