[Starlink] some post Starship launch thoughts

[Rodney W. Grimes]

> On Wed, Apr 26, 2023 at 1:41?PM Rodney W. Grimes
> <starlink at gndrsh.dnsmgr.net> 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 at freebsd.org
> 
> 
> --
> AMA March 31: https://www.broadband.io/c/broadband-grant-events/dave-taht
> Dave T?ht CEO, TekLibre, LLC
> 
>