Chair Force Engineer has a useful post on the assumptions that go into the various choices of lunar architecture, an issue on which I kvetch on at least a weekly basis, because NASA steadfastly refuses to show its work. He delves into Ares vs Direct issues much more deeply than I ever bother to do, because, frankly, both approaches are flawed. I don’t have a vehicle-design dog in the fight. I like to argue at a higher level, which is, what is our institutional approach to becoming spacefaring: NASA develops its own vehicles for its own limited needs, or the federal space establishment encourages a private space industry off of which NASA can leverage to accomplish not only its own goals, but those of others?
But for those who like to design launch systems, and get down into those weeds, CFE offers some interesting contrasts between Direct and NASA’s current approach. I generally agree with his conclusion (as far as it goes):
I would like for the next NASA Administrator to call time-out and order a re-evaluation of crew and cargo launch strategies that takes development costs into account with infrastructure and operational costs for the expected duration of Project Constellation (from now until at least 2025.) The agency should look at permutations of all realistic crew launch & cargo launch designs. Examine Ares I, Jupiter 120, Atlas V Heavy, Delta IV Heavy, and Wide-Body Atlas for crew launch. Take a gander at Ares V, Jupiter 232, and a side-mount Shuttle Derived Vehicle similar to Shuttle-C. Take a realistic look at the assumptions which are driving the Orion capsule weight (especially the amount of volume available to each crew member) and the number of man-days the Altair lander is expected to support on the lunar surface.
But there are a lot more fundamental assumptions that have to be examined. For instance, if we focus a small fraction of the billions being spent on developing unneeded launch systems instead on orbital infrastructure (EVA equipment, docking protocols and hardware, mating interfaces, tugs, etc.) and utilize innovative approaches like Bigelow’s facilities for habitat, how much would we do with existing launch systems, and future (small) space transports that could drive down costs? It would be an interesting exercise, and one that NASA has never engaged in (because the insanely wrong lesson it learned from ISS was to avoid orbital operations and assembly) to challenge them to come up with a way to get to the moon with existing launch systems. Because that is the route to becoming spacefaring.
[Update a few minutes later]
One other thought, and one that I tried (unsuccessfully) to inject into the CE&R results that we were submitting to NASA back before Mike became administrator. NASA should consider marginal costs per mission, and average costs per mission (including amortization of development costs), and let that drive them toward architectures that are scalable to much more activity. From that standpoint, ESAS is an utter disaster.