Sunday, April 30, 2023

Spacex - The engineering of launching an unlaunch-able rocket

 It is possible to design a rocket so intense that it cannot be launched in the normal way.  The rocket acts as a heat lance you see on safe-cracking movies.  The natural course would be, that the rocket digs to the centre of the earth.  This is pure geotechnical engineering we're talking about, a lost art that everybody thinks they can do with their computer.

Geotechnical engineering is about the strength of materials for rock and soil.  I also use it for earthquakes, but nobody else does.  Everybody just assumes that the strength of rock and soil is infinite.  Look at earthquake engineering using solid steel as the base-plate for shake-table tests.  Always wrong.

Spacex designed a concrete lance, which is difficult to do.  Concrete does not melt but turns to powder when exposed to extreme heat.  That's how it is made.  It is also very weak in tension, which is why we have reinforcing steel.  But high pressure tears apart concrete in local tension, which cannot be stopped by the steel.  Concrete can be easily cut apart by a water jet.

So, the big rocket, also known as 'Not a flamethrower", has everything it needs to turn concrete to dust, and blow giant concrete rocks everywhere, which is not good for rocket engines.  I suspect the rocket was flying with a dozen banged-up engine nozzles, and those are the most important part.

So, I've been thinking of a thousand ways to launch this flying pig.  You have to use methods to reduce the stress on the concrete, but still maintain the nozzle pressure.  Good old Nasti Von Braun, my hero, used a water jet for the Saturn 5, but this space disaster is a factor of 100 about that (who knows?).  Nasa banned the whole thing for reason.  There could not have been a bigger blunder.

I'm thinking of a huge rocket launcher structure that can hang the rocket way in the air.  This structure would have to be 5 times bigger than the rocket itself.  It is part 'space elevator'.  The rocket nozzles are 50 ft above the ground.  When the engines ignite, it also starts to lift the rocket up by cables, thus reducing the pressure.  Naturally, this is much more expensive, and since they have no clue as to the forces here, this structure might also blow up.  Had they a brilliant geotechnical engineer, they would have monitored everything like an earthquake, so we could figure out the forces.  

ps.  Here is my imaginary rocket going to the centre of the earth.



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