Gordon D. Pusch wrote:

For any reasonable strength of material, the amount of additional energy
that can be stored by pressurizing the tanks is negligible compared to the
chemical energy stored in the propellants themselves. About all you will do

Consider tanks that contain solid hydrogen instead of liquid hydrogen -
or more simply, contain say supercoold hydrogen at twice the pressure while
weighting no more than present ones.

by pressurizing the tanks is to allow you to eliminate the mass of the
turbopumps and drive turbines, which is likely to be marginal compared to
the additional mass of high-pressure propellant tanks. Pressure-fed rockets

But as you used much better materials, the mass of the tanks went down or
at least didn't increase much.

_may_ be justifiable on the basis of lower cost or higher reliability,
but are =VERY= unlikely to provide significantly better performance than
pump-fed rockets.


But it is not really a question of replacing the pumps with a pressure-fed
system, its a question of using better materials whichmeans that either
you can leave the mass the same - while getting higher performance *or*
reducing the mass of all compoents while still getting same performance.


-- Gordon D. Pusch

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--
Sander

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