From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 1390F3B29D for ; Wed, 26 Apr 2023 18:38:45 -0400 (EDT) Received: by mail-ed1-x536.google.com with SMTP id 4fb4d7f45d1cf-50a145a0957so954110a12.1 for ; Wed, 26 Apr 2023 15:38:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=perens.com; s=google; t=1682548724; x=1685140724; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=dzkkfiUfplOGZF45fhAgTK+JWk2TEc6syf+Fp0agBBI=; b=mWduWZMkmnuUo9DQ32KskxURq+alFYdo37Svgzv2JgOO6ubtV+y9VBhE+lH8hMNvpo hWWvxBdQCAvc7mDOPKYzkIO8Vw4pvRe8r2myWjLLjWrA5aAH8Av+a5UGhjIYyUQxjWQT OvC7pe419LORa6K6fcP26f8cOZw7fpF7ihSxY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682548724; x=1685140724; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=dzkkfiUfplOGZF45fhAgTK+JWk2TEc6syf+Fp0agBBI=; b=drqw7Lj05dsTsByE+LjHcM/RLxXarnUCJuf5YdTPTYEl+wXzcR//oG38lnUKTAJ1JY +9WUPYRI6xWzY36ZVgMiu2RhGJDbhUWk8+gxz5CeXiAUbzI8tIay5EMnu+Pry24VLRIZ Wcrj2UpbMzBl67sjf/rzh5iC1bAOF0iyQ2uOsPG/3qkaJEmZduzckr1bEmlF0HX0/yBD fnxDemxTtE0BKl2FmMx+aNBSiYDdlSGWZoKytziIMjxEDstHbuXZjfhd21/dOr2pq2um jrIEdXV9CNo9Qn/CZIzN8mG7WOMRPaBk3pzQFta7KzKcOjp7fUsMB2ElI02kYK7xRxRC FuOA== X-Gm-Message-State: AC+VfDznW1rZemC4N/uTS2dLrQZ2Q6JWL4t/1lEUlLb0ekyevkk/eg+s c5wdWcLUfSVkyBoyHm/ucWuUohoT5NdO4I8491ScDL+4PiIgr+yS2IU= X-Google-Smtp-Source: ACHHUZ6la1BbczIvz/YSrilMOUgwLTDhC7qPKscUhKP5qGdHlq9SGX3j6jEp13Pb2qL6uBqRVBdwSJhh4ejP22xKgK4= X-Received: by 2002:a17:906:390e:b0:94e:bcb6:5f31 with SMTP id f14-20020a170906390e00b0094ebcb65f31mr3269959eje.20.1682548723760; Wed, 26 Apr 2023 15:38:43 -0700 (PDT) MIME-Version: 1.0 References: <202304262231.33QMVPgZ097387@gndrsh.dnsmgr.net> In-Reply-To: <202304262231.33QMVPgZ097387@gndrsh.dnsmgr.net> From: Bruce Perens Date: Wed, 26 Apr 2023 15:38:32 -0700 Message-ID: To: "Rodney W. Grimes" Cc: Dave Taht , Dave Taht via Starlink Content-Type: multipart/alternative; boundary="000000000000ff589505fa44e657" Subject: Re: [Starlink] some post Starship launch thoughts X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Apr 2023 22:38:45 -0000 --000000000000ff589505fa44e657 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Note that if SpaceX wants a sacrificial coating, they have PICA-X and the sintered silicon tiles. On Wed, Apr 26, 2023 at 3:31=E2=80=AFPM Rodney W. Grimes via Starlink < starlink@lists.bufferbloat.net> wrote: > > On Wed, Apr 26, 2023 at 1:41?PM Rodney W. Grimes > > wrote: > > > > > > > As always I enjoy the flood of information we get on this list! > > > > > > > > still, so far, my research on a nitrogen deluge system (instead of > > > > water) has come up empty for me, except as a fire suppressant. So > it?s > > > > either crazy or brilliant. Or both! I really liked the idea of > > > > something cooler that was a natural byproduct of the LOX process... > > > > > > I dont think cooler does much, isnt it the "energy of vaporization" > > > that is actually doing all the "work" in this type of system? > > > > > > H2O is 40.7 kJ/mol and LN2 is 5.6 kJ/mol so you would > > > need ~7 times as much LN2 to do the same work. > > > > Now that! was the kind of numbers I was looking for! > > :-) > > > > > Still, water has to come from somewhere, and be stored. I will keep > > thinking about it. I like that they seem to think that a water cooled > > steel plate will suffice. > > Water is a pretty ubundant resource... > > Now that water cooled steel plate, if you treat it like a sacrificial > anode in a water heater, ie you expect it to be erroded over time it > could get interesting. Energy of vaporization of steel well... lets > call it iron (Fe) is 340kJ/mol. Large thick plates are rather easy > to manufacture, and I am sure they could design the ficturing such > that the blast held them in place against a concrete foundation. > > Also there is probably lots of good research on keeping water > in contact with steel at high temperatures and volumes, think > Boiling Water Reactor! Containing the flying molten slag would > be a concern I suspect though. > > > > > > And the reason N2 is used as a fire suppressant is again not > > > because of temperature, but because it displaces the O2 and > > > suffocates the fire. N2 is also easier on our ozone layer > > > than the prior used Halon. Finally, this is usually > > > compressed N2 gas, not LN2. > > > > > > -- > > > Rod Grimes > rgrimes@freebsd.org > > > > > > -- > > AMA March 31: > https://www.broadband.io/c/broadband-grant-events/dave-taht > > Dave T?ht CEO, TekLibre, LLC > > > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > --=20 Bruce Perens K6BP --000000000000ff589505fa44e657 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Note that if SpaceX wants a sacrificial coating, they have= PICA-X and the sintered silicon tiles.

On Wed, Apr 26, 2023 at 3:31=E2=80= =AFPM Rodney W. Grimes via Starlink <starlink@lists.bufferbloat.net> wrote:
> On Wed, Apr 26, 2023 at 1= :41?PM Rodney W. Grimes
> <st= arlink@gndrsh.dnsmgr.net> wrote:
> >
> > > As always I enjoy the flood of information we get on this li= st!
> > >
> > > still, so far, my research on a nitrogen deluge system (inst= ead of
> > > water) has come up empty for me, except as a fire suppressan= t. So it?s
> > > either crazy or brilliant. Or both! I really liked the idea = of
> > > something cooler that was a natural byproduct of the LOX pro= cess...
> >
> > I dont think cooler does much, isnt it the "energy of vapori= zation"
> > that is actually doing all the "work" in this type of s= ystem?
> >
> > H2O is 40.7 kJ/mol and LN2 is 5.6 kJ/mol so you would
> > need ~7 times as much LN2 to do the same work.
>
> Now that! was the kind of numbers I was looking for!

:-)

>
> Still, water has to come from somewhere, and be stored. I will keep > thinking about it. I like that they seem to think that a water cooled<= br> > steel plate will suffice.

Water is a pretty ubundant resource...

Now that water cooled steel plate, if you treat it like a sacrificial
anode in a water heater, ie you expect it to be erroded over time it
could get interesting.=C2=A0 Energy of vaporization of steel well... lets call it iron (Fe) is 340kJ/mol.=C2=A0 Large thick plates are rather easy to manufacture, and I am sure they could design the ficturing such
that the blast held them in place against a concrete foundation.

Also there is probably lots of good research on keeping water
in contact with steel at high temperatures and volumes, think
Boiling Water Reactor!=C2=A0 Containing the flying molten slag would
be a concern I suspect though.

>
> > And the reason N2 is used as a fire suppressant is again not
> > because of temperature, but because it displaces the O2 and
> > suffocates the fire.=C2=A0 N2 is also easier on our ozone layer > > than the prior used Halon.=C2=A0 Finally, this is usually
> > compressed N2 gas, not LN2.
> >
> > --
> > Rod Grimes=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0rgrimes@freebsd.org
>
>
> --
> AMA March 31: https://www.broadband.= io/c/broadband-grant-events/dave-taht
> Dave T?ht CEO, TekLibre, LLC
>
>
_______________________________________________
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Starlin= k@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/starlink


--
Bruce Perens K6BP
--000000000000ff589505fa44e657--