"Henk Boonsma" wrote in
news:1103793537.1545802e182bbfe92208c7ee60cca5cc@t eranews:

The new Delta IV-H and (possible) Delta V-H ELV's still fall far short
of the performance of the Saturn V moon rocket. At the moment they
have about a quarter of the latter's performance. I'm beginning to
wonder if it's even feasible (both technically and economically) to
even upscale these things to Saturn V performance. Wouldn't it be
easier jjust to start from scratch and design another 100 ton LEO
booster with a 10 meter fairing? Anyway, if it is at all possible to
scale these things to Saturn V performance it will take at least
another 3 generations.

3 generations? Not at all.

Delta IV (and Atlas V) have a potential advantage in their
modularity. A Saturn V class heavy lifter tends to be very
expensive and there isn't any call for one at present. We
certainly could use more affordable not-quite-Saturn-class
lift.

Check here for an example of how Boeing thinks they can get
much more performance out of the basic building blocks that already
exist:

http://www.boeing.com/defense-space/.../d4heavy/docs/
delta_growth_options.pdf

At some point, clustering the existing CBCs gets unwieldy and
hits an upper limit in performance; Boeing proposes a new and
larger CBC for a next-generation heavy lifter that achieves
and exceeds Saturn V class performance.

Lockheed-Martin has very similar proposals for the Atlas V.

If you need bigger, just wave sufficient money at the right
parties. There's no technologicial limit to heavy lift.

High energy might been another thing, however. Going to Mars
is almost certainly need nuclear propulsion to get beyond
Earth orbit, if it's to be done right and in timely fashion.

--Damon