Space Shuttle Noise Deadening ...Why???

[bartman]

Almost a year ago, Rolf posted this:
http://www.iceinspace.com.au/forum/showthread.php?t=69338&highlight=ascent
Absolutely amazing..... but.....

Something that caught my interest ( amongst others things.... like the 150 inch Bashir(?) lens with 4000mm focal length, 250 pounds, at the 38:24 mark of the video.) .....

is ..... Why do (did) they have noise deadening devices for the Shuttle launches? ( 17:10 mark of the video is an example)

Whats the reasoning/ Science behind that?
Surely it cant be for the Public or Fauna....????
Anyone have an insight to that?
Ive had no luck on Google....must be those cookies & FB (http://www.iceinspace.com.au/forum/showthread.php?t=83255)...:lol:

Cheers
Bartman
http://www.youtube.com/watch?feature=player_embedded&v=W2VygftZSCs

[mithrandir]

The guide on the Kennedy Space Center tour said something about how many dB the water spray reduced the volume by but I can't remember it off hand.

Quote (http://www.nasa.gov/missions/highlights/webcasts/shuttle/sts110/shuttle_qa.html):

Charlie from London U.K.
How many gallons of water are sprayed onto the launch pad during the launch of a shuttle?

That's a relatively easy one. There are about 300,000 gallons of water. And if you look at the launch pad, or at some of the pictures we have of the launch pad. Just to the northeast you will see this huge water tower and in that water tower and in the huge piping that comes down from it, we have about 300,000 gallons of water. And at T minus 16 seconds we begin to flow the water underneath the launch pad. That's sound suppression water, in order to stop the echo of the engine ignition and going down and hitting the bottom of the pad then bouncing back and knocking tiles off the orbiter. So about 300,000 gallons of water will flow in 30 seconds. As the orbiter begins to lift off you may have seen in some slow-motion photos right at the pad deck there are these huge stand pipes. We call them rainbirds, and they begin to spray water all over the pad surface to cool and also to deaden the noise there as well.

Quote (http://wiki.answers.com/Q/Why_is_there_so_much_smoke_during_s pace_shuttle_and_rocket_launches):

Why is there so much smoke during space shuttle and rocket launches?

The majority of the white clouds seen during the first few seconds of a shuttle launch is actually steam, not smoke. To dampen the noise from the powerful rocket motors on the shuttle, approximately 400,000 gallons of water are sprayed underneath the exhaust for six seconds before launch and fifteen seconds afterward. When the hot exhaust hits the water it evaporates, making an enormous cloud which will eventually precipitate and turn into rain.
Without this sound dampening system, the immense blast of noise from the shuttle launching would likely break windows for miles around the launch site.

[deejayvee]

I saw this on the Engineering Connections (http://en.wikipedia.org/wiki/Engineering_Connections#Series_3_.2 82011.29) episode on the Space Shuttle. The show included a practical demonstration of the effect.

[Nightshift]

It is for the fauna as well as the tourists and also some sensitive monitoring equipment on the pad itself. When they light the SRB's they actually explode in to life, not burn, the shockwave is intense. Kennedy space centre was built in the middle of a wildlife sanctuary and provisions were made by the national parks service that the space administration must protect the wildlife or vacate the premises. NASA take preservation at Kennedy very seriously. If a turtle is crossing the road all traffic must stop and give way to it. If a gator is sunning itself on the roadside you are not allowed to disturb it, if a massive controlled explosion takes place you must make it as quiet as possible.

Cheers, Dennis.

[bartman]

Thanks for the responses peoples....
Still trying to find a 'catch up' episode of that engineering connections.....got lost looking at other eps in the mean time heheheheh.
Andrew,thanks; the echo shockwave knocking tiles off sounds plausible, but...... mmmmm dont know........
Dennis, Thanks too. KSC builders must have been pretty desperate to build in a wild life sanctuary!!!! Also sounds plausible .....but it still is a big boom(sfw but different) (http://www.youtube.com/watch?v=BA-IwlhquiM) when it takes off. Spectators from k's away can still hear and feel the blast off ( here (http://www.youtube.com/watch?v=xsRuJ37kyZg&feature=related) - even a car alarm goes off- here (http://www.youtube.com/watch?v=Z-GivwKsBJY&feature=fvwrel)- one of the ladies looks worried- and here (http://www.youtube.com/watch?v=BeKafWCZvMQ&feature=related) - where you see a bird being scared by the noise :( at 0:16) and has a great wide angle shot too btw)

Anyhoe, Ill keep trying
Thanks
Bartman

[mithrandir]

Cape Canaveral is about 570 km2. There are buildings and launch pads spread over a large part it, but in total they occupy about 1% of the area. The rest is sanctuary. Apart from the occasional hurricane, it is the best site for launching in the continental USA. It's the furthest south giving the greatest launch assist from the earth's rotation, and furthest east with a large chunk of water to drop spent stages and failed launches into.

In mid October they opened the VAB to tours, and we visited it on the 28th. I'll see about adding a thread with some photos when I get home.

[ballaratdragons]

Sound Suppression water test being carried out shows the amount flooded onto one spot!
During launch, 350,000 US gallons (1,300,000 L) of water are poured onto the pad in 41 seconds.
http://upload.wikimedia.org/wikipedia/commons/9/9e/Sound_suppression_water_system_test _at_KSC_Launch_Pad_39A.jpg

[Kevnool]

Awesome pic Ken

[erick]

Make a good carwash? :D