"gaetanomarano" wrote in message
ups.com...

Jeff Findley ha scritto:

From past discussions, I believe I remember that the crawlers can't
handle
the weight of four SRB's. Note that the SRB segments are solid fuel and
come fueled from the factory. These things are freaking heavy!
Astronautix.com says they're 1,299,990 lb each fully fueled. By
comparison,
the first stage of the Saturn V was 298,104 lb empty. The shuttle's ET
is
65,980 lb empty. So adding two of these means adding about 2.6 million
pounds to the stack since you're not going to save much by "slimming
down"
the center stage.

From what I understand, that's why the launch tower was taken off the MLP
when they converted them from the Saturn V to shuttle configuration. The
SRB's are *heavy* when compared to an empty liquid fueled stage of the
same
performance.

I suppose you could scrap the existing MLP's entirely and build newer,
lighter ones to offset the mass of the two extra SRB's, but I think
that's
still a lot to ask for since the MLP is about 9 million pounds. I'm not
sure what would have to change, if anything, in the flame trench. New
flame
deflectors?


the AresV mass will be over 3350 mT at lift-off (65% higher than a
Shuttle that is about 2000 mT) and the main tank diameter will be 10 m
(vs. the 8.4 m of the Shuttle) so, EVERYTHING must be CHANGED and
REINFORCED to launch the AresV

I'm not so sure about that. You see, even with Saturn V, you roll out with
your liquid fuel tanks empty and fuel them on the pad. The problem isn't so
much that the MLP can't support the fully fueled weight of an Ares V (it
could support a fully fueled Saturn V *with* launch tower mounted to the
MLP). Getting the MLP plus the stack containing 4 fully fueled SRB's to the
launch pad using the crawler-transporter is the problem. From past
discussions in this group, the crawler-transporter is the weakest link.
Again, this is why the launch tower was removed from the MLP's when
converted from Saturn V to shuttle configuration.

my AresX will weigh about 15% more than an AresV (then, about 3800 mT)
since it must lift the same payload + an extra 15% of mass (the
Orion) ...not a big problem

Again, it's not the liftoff weight that's the problem, it's the weight the
crawler-transporter has to move that's the problem.

the cost of the (AresV OR AresX) launch pad will be a minimal fraction
of the ESAS costs and just made ONCE

however, I think that NASA should evaluate the option of an on-pad
assembly of the AresV/X 1st stage

You're kidding, right? We already had a huge delay due to an ET getting
pummeled by hail while sitting on the launch pad, what do you think that
would do to stacking operations? That's the point of the VAB! The problem
is the heavy, hard to handle solids. They make stacking operations
difficult and they *greatly* increase the mass needed to be moved to the pad
when compared to liquids of similar performance.

You could create one hell of a liquid fueled launch vehicle and still fit in
the VAB and stay within the crawler-transporter weight limits, but solids
are another story.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)