<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">I found this YouTube of a deluge system test.<div class="">It doesn’t look like it uses enough water to succeed.</div><div class="">My intuition is the mass of water needed is approximately equal to the rocket’s mass. </div><div class="">Maybe the system doesn’t have to fully absorb the momentum of the engine exhaust. Still, 70% would be a much greater mass than what the video shows.</div><div class=""><br class=""></div><div class="">Has anyone seen a rough calculation of what is needed from the deluge system?</div><div class="">Some elements</div><div class=""><ul class="MailOutline"><li class="">mass of water to absorb/dissipate the thermal energy</li><li class="">mass of water to absorb/dissipate the momentum of the rocket exhaust.</li><li class="">the rocket engine exhaust momentum is greater than the weight of the rocket.</li></ul><div class=""><br class=""></div><div class="">Are there tricks that I don’t know about?</div><div class="">
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text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span class="Apple-style-span" style="orphans: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: none;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span class="Apple-style-span" style="orphans: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: none;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span class="Apple-style-span" style="orphans: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: none;"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><span class="Apple-style-span" style="orphans: 2; text-indent: 0px; widows: 2; -webkit-text-decorations-in-effect: none;"><div style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-transform: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class="Apple-interchange-newline">Gene</div><div style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-transform: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">-----------------------------------</div><div style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-transform: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">Eugene Chang</div><div style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-transform: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="mailto:eugene.chang@alum.mit.edu" class="">eugene.chang@alum.mit.edu</a></div><div style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant-ligatures: normal; font-variant-position: normal; font-variant-caps: normal; font-variant-numeric: normal; font-variant-alternates: normal; font-variant-east-asian: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-transform: none; white-space: normal; word-spacing: 0px; border-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">+1-781-799-0233<span style="-webkit-text-decorations-in-effect: none; text-align: -webkit-auto;" class=""> </span><span style="-webkit-text-decorations-in-effect: none; text-align: -webkit-auto;" class="">(in Honolulu)</span></div></span><span class="Apple-style-span" style="-webkit-text-decorations-in-effect: none;"><div style="border-collapse: separate; 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font-family: Helvetica; font-size: 15px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class="Apple-interchange-newline"></div></div></div></div></div></div></div></div></div></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Apr 25, 2023, at 12:31 PM, Bruce Perens <<a href="mailto:bruce@perens.com" class="">bruce@perens.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div dir="ltr" class=""><div dir="ltr" class=""><br class=""></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Apr 24, 2023 at 7:20 PM David Lang via Starlink <<a href="mailto:starlink@lists.bufferbloat.net" class="">starlink@lists.bufferbloat.net</a>> wrote:</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
If they dig a pool under the Starship Launch Mount, it will fill with water <br class="">
(they are already having to pump water out of the hole the rocket dug), if they <br class="">
line it with concrete, water will seep through, and the concrete will try to <br class="">
float on the water.</blockquote><div class=""><br class=""></div><div class="">The deluge system produces a mixture of water and air. That is necessary for the acoustic deadening effect.</div><div class=""><br class=""></div><div class="">Once upon a time, there was a thing called Orion, which was supposed to be a big heavy shield that would be propelled into space by setting off atomic bombs on one side of it. Lots and lots of bombs. At some point people thought they could make a shield good enough. What SpaceX puts in now is going to be the closest we have come to Orion, just upside down.</div></div></div>
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