NASA tests noise suppression system on rocket scale model

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HUNTSVILLE, Ala. (WHNT)-- NASA is testing techniques for crew and equipment safety on their new rocket, the Space Launch System (SLS.)

It's more powerful than shuttles of the past, with 25-thousand pounds of thrust. But that also means it's extremely loud-- 120-180 decibels loud. That could endanger the crew and even the rocket itself.

Jeremy Kenny, a NASA Acoustics Engineer, put it into perspective.

"Those kind of levels not only instantaneously, but permanently, cause human hearing loss," he said.

But it doesn't just endanger the crew during the launch.

"The noise levels can actually vibrate the vehicle structure itself, and fatigue and break it," said Kenny.

To protect people, and the rocket equipment, NASA has designed and already put to use a system that deploys water at the launch site to stifle some of that noise.

Kenny said, "The sound waves, during liftoff, come from everywhere. Come from the flume strike the pad, then reflect back off the vehicle. So the water, among other things, can dampen the sound waves as they try to pass through."

Because the SLS involves a different  than the other rockets that have used the water suppression system. It has a different launch structure, using 4 engines and 2 boosters.

Crews have been testing a scale model of it to see how loud it can get, and how much water is needed to quiet it, because the water suppression system is not one-size-fits-all.

The model they've been using is 5-percent of the size of a real SLS, so around 3,000 gallons of water are used for the tests. On the actual SLS it could be hundreds of thousands.

Each of the "elevation series" of tests sets the rocket at different heights to simulate a liftoff. The noise is measured at each height, along with the amount of water needed to bring it down to the appropriate levels.

"We could exercise in a subscale sense what the levels would be and what the noise suppression system should size to be," said Kenny.

During and after noise suppression, testers use fresh water and it's non-toxic when the test is complete. Water is an inexepensive and affordable way to figure out the noise issue, Kenny explained.

Using a scale model like this means they don't have to use the real rocket, but also, they're wasting less resources as they make these key calculations. That saves NASA time and money.

NASA has done 34 tests including the one we attended Thursday. There are 4 more tests needed before engineers feel confident about applying what they've learned to the full-scale SLS.

(Some of the video used in the story above was provided by NASA.)