Dennis Wingo (a.k.a. wingod around these forums) has written a thought provoking article about the VSE on Spaceref. ( http://www.spaceref.com/news/viewnews.html?id=1285
) The article makes the very valid point that VSE is focusing too much on how to get to the moon instead of what we should do on the moon (and that because of this, VSE doomed to failure just like SEI).
Here's a little quote for the Direct and/or EELV supporters:
"The problem is not the rocket, it is the plan of what we do when we get to the Moon. While there are many who would strenuously argue that the transportation architecture represented by the ESAS study as implemented with billions of dollars of taxpayer money is the wrong one, in the end, this argument misses the greater point."
I have to agree with the notion that the goal of VSE should be not simply returning to the moon as a stepping stone to mars, but actually doing something useful there too.
But I do think that the rocket is a big part of the problem too. More specifically, the problem is what the architecture choice does to NASA's budget.
Ares I and V suck up all the budget NASA has available and then some, bringing us back to the budgetary unsustainability of the Saturn V era. While NASA's VSE pays lip service to the idea of a permanent lunar base, enacting Constellation means that no money is left to even bother planning the details of more than Apollo style boots-and-flag missions within NASA's current financial envelope. Conversely, the financial estimates I've seen suggest that Delta and/or Atlas EELV would mean very expensive lunar missions launched in very tiny segments: the costs would quickly add up to outweigh even Constellation. Delta and Atlas make great economic sense if all we want is LEO crew and cargo launches to ISS, but very little economic sense for lunar missions.
So... only an not-too-big, not-too-small, just-right "Goldilocks" solution would allow NASA to still have some budget dollars left to fund actually doing something of any significance on the Lunar surface. And that leaves us with true SDLV heavy-lift as the only way I see for NASA to get to the moon and still be able to afford to do something useful there.
This is starting to sound familiar: 8.4m core, 4-seg SRB, disposable RS-68 engines, and either an in-line payload (Direct) or side-mounted payload (disposable Shuttle-C type fairing). The difference in the costs between these two options seems practically negligible (a few hundred million on a $300-billion program). Shuttle-C may save some initial development and infrastructure costs, but side mount payload implies a need for an EELV to serve as crew launcher. And that, in-turn, implies a "gap" with the very real political risks of the loss of STS infrastructure, workers, and knowledge. Direct can serve as the launcher for everything needed for LEO, lunar, and even Mars missions, but costs more up front to develop the in-line config and the needed pad and MLP changes at KSC.
Nothing else will get NASA back to the moon within the next decade. (Except Branson, Carmack, Bezos, and Musk, of course :laugh: ).
(Of course, I expect that a few people here may somewhat disagree with my views in the most polite and genteel manner....)