Submitted by teryret t3_10vu07s in space

I was just watching a video (namely: https://youtu.be/Ax6yV8ZC_bc?t=117) and the presenter mentioned that SpaceX has three basic options to keep from having to rip up all the concrete after each booster static fire: Come up with better concrete, dig a big trench, or to use a water deluge system. But then he goes on to say that "dig a big trench" isn't viable because it would be below the water table and thus flood.

... But who cares if it floods given that "water deluge" is one of the other options you're considering?

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abcxyztpgv2 t1_j7jh1kn wrote

Water is best sound suppression method. Concrete won't last long. Walls won't last. Not extensible. Not reusable for multiple launches. Can get cracks. Can blast and hurt rocket. Remember Colombia incident of 1 tiny tiny thing led to disaster. Water is best option.

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MrZorg58 t1_j7jh2dp wrote

The water serves two purposes. One to help keep the tower and such cooled. The other use is for sound suppression. Rockets are loud, and water dampens that sound pretty well.

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komatiitic t1_j7jjuel wrote

In addition to everything else because they're basically on the ocean the water that would flood the big hole would be salty, and salt water is bad for pretty much everything. Corrodes and degrades, so you probably don't want to be spraying it all over your very expensive rockets.

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Nydcn77 t1_j7jqhky wrote

Deluge systems have been used for a long time. At least as far back as Apollo. It absorbs the shock waves from all that thrust. It does some cooling but mostly absorbing shock by flashing to steam and cushioning the pressure waves. It's still basically a massive controlled explosion. You can see it really well in the Shuttle launches but not so much Apollo. What you also see is that the pad is pretty much incinerated. One of the reasons for long turn around times. As far as ditching the pads are raised and there is a large pit there to direct the thrust away from the pad. Search for launch pad videos on you tube.

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Thorazine88 t1_j7ltmx5 wrote

I believe the issue is “Which is better: 1. A water deluge system which pours a huge amount of water between the rocket exhaust and the concrete pad. 2. A pool of water underneath the rocket exhaust.” I’m guessing a pool of water wouldn’t be as good because the rocket exhaust would blow hot water and steam everywhere in an uncontrolled manner.

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Chork3983 t1_j7o2n91 wrote

I'd think it would just push the water out of the way right? Like if you have a puddle and you turn a leaf blower on it you'll blow the water away to expose the ground underneath. I'm thinking the same thing would happen in this case.

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