SpaceX Rocket Water Launch System

If you've ever seen a rocket launch, you may have noticed a huge amount of water being drained to the launch pad. What is it used for?

The missiles must withstand great stress during their launch from the launch site. And so is the ramp itself. The launching rocket spews a stream of flue gases at enormous speed and threatens great damage every time it takes off.

For example, the exhaust gases of the Merlin 1D engine leave the nozzle at a speed of 2.77 km / s and have a temperature of approximately 1,500 ° C. The flue gases thus exceed the speed of sound several times, which at a temperature of 20 ° C is stated to be 343 m / s. When the flue gas collides with the surrounding air, a shock wave is created and everyone who has ever heard a supersonic plane in the sky can probably imagine the noise that is generated during this process.

The flue gas flow leaving the rocket engines must therefore be regulated, because if it were directed perpendicular to the ground, it could subsequently bounce and damage the starting rocket, either by the heat itself or by reflected sound waves.

To prevent possible damage to the rocket or launch pad, the rockets have not been fired directly from level ground for a long time, but the launch complexes for the rockets are specially built. Each space program country has decided to address this issue differently. The solution chosen by NASA will be shown on the example of the LC-39A ramp at the Kennedy Space Center, which has been leased to SpaceX since 2014.

An inclined deflector (baffle) is located under the rocket, which deflects the flowing flue gases to the sides, thus preventing them from bouncing back towards the launching rocket. The deflector is 13 meters high, 15 meters wide and weighs 317 tons.

However, when the rockets are launched, it is not just the flow of hot flue gases, but also the sound energy that is generated when the rockets are launched. This energy is considerable and if it was not attenuated at the start, it could be reflected and damage to the ramp itself, the carrier or the crew cabin.

To prevent this danger, the starting ramps, the mobile platform, the flue gas deflector and the access arms for the operator were flooded with water.

The sound waves created by the ignition of the engine oscillate when colliding with water molecules, heating them, which reduces their energy.

For this purpose, it built a reservoir near the starting ramp with a height of 88 meters, in which a total of 1,135 tons of water is prepared. A few seconds before the start, this water is then discharged to the starting ramp at a rate of approximately 57,000 l / s or 3.4 million liters per minute.

It is stated that out of the total amount of water sprinkled during the start ramp, a total of 200 tons evaporate, 10 tons decompose into atoms and the rest ends up around the ramp. In this way, the noise of the launching rocket is reduced from more than 200 dB to 142 dB.