"Cris Fitch" wrote in message
om...
Not long ago it looked like the Medium lift market was
over-subscribed with Proton, Ariane-5, Sea Launch, Atlas-5
and Delta-IV. Now with the retirement of Shuttle and a
new plan for manned exploration coming into being, we've
got to ask ourselves:

Yep the market is about to get a lot bigger.

One of the things to remember is all the current rockets are designed for a
mix of LEO and GTO not LTO or Lunar orbit.
Some changes will naturally be made to better suit this new objective.


1) Launch lots of medium payloads
or
2) Go Heavy

I've got to argue in favor of #1, hoping that the economics
of all these medium lift launchers will reduce the overall
cost of these plans. Standardize the payloads (a la the building
of MIR) and assemble what you need for each mission. Pay
companies for the results (e.g. fuel delivered to the right
orbit).

I do not see how you can go with medium launch vehicles unless you count a
Delta Heavy as a medium class launch vehicle.
The Delta 5,4 can only place less then 5 tons into LTO. With launch capacity
like this you would need at least 40 launches and maybe as many as 80
launches a year just to maintain a 4 man base. Too much assembly can cause
many of the same problems we see now with ISS.



If one feels it necessary to go for heavy lift, can't we at
least think in terms of "Delta-IV Super Heavy", such that
our flight hardware makes use of the engineering and production
already in use (and that will stay around if the politics of
heavy lift fails)?

This has a lot of potential.
Going from just over a 5 meter diameter rocket to an almost six meter
diameter rocket even if only for the central rocket would allow for a lot
more launch capability in a Delta Heavy.
Dual MB-60 second stage could also increase mass to orbit.

Increasing the thrust of the second stage with either a MB-60 or RL-60 and
adding a third stage is IMO a must.