"Henry Spencer" wrote in message
...
In article ,
DGH wrote:
1) Development costs ~ Almost all the designs being proposed for heavy
lift
are using existing flight tested components.
This should cause major reductions in development costs. It should cost
around what the EELVs did to develop.

Depends on how it is done, and by who. NASA's estimate for development of
Shuttle-C, a decade ago, was several times that.

Anything is possible.


2) Cost ~ The cost seems a little high based on that we already know the
cost of the individual components.

It is by no means a foregone conclusion that we already know the costs of
the components. That depends on the *choice* of components.

Moreover, especially for the low launch rate one would expect from an
HLLV, component cost is almost irrelevant. What matters is the size of
the standing army, both at the factory and at the launch site, because
they have to be paid no matter how much or how little they launch.

Agree. That is why I suggest it only when the launch model gets high enough.
I have said before the cut off point seems to be around 24 Heavy EELVs
If we want less then a million pounds a year to orbit for the Moon Mission
then forget any Heavy lift.



3)Market ~ First the average satellite mass has been increasing for some
time and is unlikely to stop doing so. The use by NASA of this rocket
peaks
in the Early 2020's so we are talking about the Market in the late 2020's
and beyond commercial and Military satellites should be very large by
then.

Maybe, and maybe not. Such predictions are rather uncertain... as are
predictions of competing systems that might develop in those twenty years.

Third the most common design of these rockets without the shuttle solids
are
very similar to a Delta IV Heavy which a market already exists for.

The only existing market for Delta IV Heavy, if I recall correctly, is two
launches for the NRO. Hardly a solid customer base.

The same weight class includes the Araine 5, Atlas Heavy and just a little
lower Sea Launch.
These vehicles make up a large percentage of the market in dollar terms.


4)Orbital assembly ~ ISS strikes again. Those who fail to learn from
history are bound to repeat it.

Ah yes, the Wile E. Coyote approach to engineering: if it doesn't work
once, the whole approach must be infeasible, so throw it out and try
something entirely different, rather than trying to debug it.

No just simple logic. One part would be automated assembly the other would
be less assembly.
At the higher end even with 150,000 pound heavy lift you still have you
would still have 20 launches.
That would still be a lot of orbital assembly.


The main thing we learn from the history of the shuttle and ISS is not to
put JSC in charge of a major space project. (MSC was a much more capable
place, but it's gone.)

This would take between 24 and 40 EELV Heavy launches a year. The high
end
would take many more EELVs then the plants are designed to produce...

We could, of course, enlarge the plants, or invest in automation of the
existing ones (Khrunichev goes from sheet metal to a finished Proton in
eleven months, something neither EELV plant can match). Either is likely
to be cheaper than developing an HLLV. In fact, changes like *these*
could probably be privately financed, if the government was willing to
commit to volume purchases of rockets.

Since they would never know when the contract might end it would be real
hard to get them to build another plant.
Traditionally they design a new rocket when this happens. A three engine
version would be under current circumstances most likely since it has engine
out capability for man rating an item which is already going to have funds.


It would probably be cheaper to look at minor improvements to the existing
rockets.
The MB-60 and RL-60 come to mind both will give nice additional capacity.
Another option might be reuse of rocket engines.

I do not rule out an EELV only system.
I am just not ready to rule out a HLV assisted system either.
Both have advantages.
Both have disadvantages.
As we move forward and the plan takes shape we will then see which is better
for that plan.