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When NASA began launching Shuttle missions, it became clear that the MLP might inadvertently pose a danger to the crew or the vehicle: massive acoustic shock waves and rocket exhaust can bounce off the platform and hit the shuttle as it lifts off. This was true for the Saturn V launches as well, but there was less risk because the Apollo modules, atop the 111 m (363 ft) stack, were much farther away from the engines. Because the Shuttle was about half the height of the Saturn, the crew-cabin and payload bay were much closer to the platform and much more vulnerable to the tremendous forces bouncing back off the MLP - on the first mission, STS-1, the shock waves damaged many of the protective thermal tiles.[citation needed]

NASA's solution to this danger was to cushion the MLP at every launch with a flood of flowing water. Starting 6.6 seconds before engine ignition, a 1,100,000-litre (300,000 US gal) water tank at the launch site began dumping water down a pipeline and into the exhaust vents of the MLP. Next, six 3.7 m (12 ft)-high towers known as "rainbirds" began to spray water over the MLP and into the flame deflector trenches below it. The water absorbed some of the bruising forces of the acoustic waves, and discouraged fires that might be caused by the rocket exhaust. This water-dumping mechanism, known as the Sound Suppression System, emptied the launch pad tank in around 41 seconds.[3] The giant white clouds that billowed around the shuttle at each launch were not smoke, but water vapor generated as the rocket exhaust boiled away huge quantities of water.[4] The suppression system reduced the acoustic sound level to approx 142 dB.