Re: [Starlink] some post Starship launch thoughts

["Rodney W. Grimes" <starlink@gndrsh.dnsmgr.net>]

> On Wed, 26 Apr 2023, Rodney W. Grimes via Starlink wrote:
> 
> > 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.
> 
> They are designing towards hourly launches, so I don't expect it to be planned 
> as a wear item. The way it was introduced (prior to the launch) was that even 
> steel plate would wear if it wasn't water cooled.

They had best consider that as a wear item.  Those steal plates are going
to rust, no mater what they do, and at those temperatures I expect the
surface rust rate to be rather high.  Even if you water cool the back
side the exposed surface is going to get very hot, anyone have the
exhaust gas temperatures of starship?  

While findin that temperature I found:
Kennedy 39A and 40 did have flame trenches lined with fire bricks, until successive
Shuttle launches blew them out and for some distance. Both flame trenches are now
lined with a thin layer of replaceable fireproof concrete. 

So seems NASA has done this science.... I hope SpaceX is paying attention!

That temperature is suppose to be 2810C, steel melts at ~1500C, and
vaporizes at 2860C, I would say they better plan on regular replacement
of those plates, even water cooled.

Its probably time to let this thread die... and wait to see what they
come up with.
--
Rod Grimes                                                 rgrimes@freebsd.org