One of the most important tasks aerospace engineering has to solve was the exhaust acoustic level caused by the great speed the rocket is launched. When the supersonic exhaust collides with the air around it, the shock waves form, which further generate a noise level, which rises to 180dB. At these levels, the sound could possibly kill at close range. This was a challenge for the engineers, as both the astronauts crew and the assistance team were in danger.
The engineers have found a sound suppression system which flows water onto the launch pad at extremely high rates: 57 cubic metres of water per second. This countermeasure brings down the noise level to 142 dB. Without this measure, the acoustic waves can also endanger the whole rocket’s integrity and the astronauts lives, because the sound waves reflect from the launchpad back to the rocket.
On the launch of Saturn V, the first successfully launched rocket, the sound waves were captured on seismometers at large distances from the launching site.
For the rockets, the sound is a big issue, but for the vehicles flying supersonic, this problem does not exist. When the aircraft goes supersonic, the sound is being cut off, because the sound waves are being left behind by the speed at which the vehicle operates.
The rocket science is subject to the same four variables: thrust of the engines, gravity or weight, drag and lift. The form of the rocket itself is an ingenious design that minimizes drag. The aerodynamic conic noise and the long and thin shape of the rocket are designed to increase the aerodynamics of the rocket. After the launch, as the speed and altitude rise, the atmosphere thins, thus the vehicle achieves the maximum aerodynamic drag point, Max Q. The body of the rocket is on the edge of instability, which can lead to failure mode.