1. As you said, we need the moon to practice “the process of establishing a habitat elsewhere in a location that is somewhat easy to get back and forth in reasonable time.” Why do we need the moon for that? Why couldn’t we just construct our mock habitat in Antarctica (As the Mars society has done.) You get all the difficulties of isolated living, without the hassle of going to the moon. In addition, Antarctica would provide a more realistic simulation of the problems Mars explorers would face, while the moon will force them to deal with challenges they would never see on Mars.

2. Radiation is not a threat on a voyage to Mars. I strongly recommend Robert Zubrin’s “A Case for Mars” for a very lengthy discussion of this topic. He concludes that with basic shielding, a Mars crew will be exposed to an elevated, but not significant and certainly not dangerous dose of radiation.

3. We also don’t have to worry about the effects of long-term exposure to micro-gravity. In fact, Martian explorers need not experience micro-gravity at all for any significant time. Again, as Zubrin describes in his book, it is possible to simply pay out a few hundred meters of cable, and set your spacecraft in a slow spin, and generate artificial gravity.

1. Yes, there is a major revamp of the Apollo design. They are retaining the Apollo conceptual design, but the design is being modified for a crew of 4, and will be extensively updated.

2. Coming and going will be accomplished by Apollo style vehicles rather than Shuttle style vehicles. That doesn’t preclude some ability to reuse the command modules, but the lander return vehicles will likely be jettisoned and burn up on reentry.

3. They are not requiring water to be present in the craters to succeed. They are hoping to find volatiles such as water because that could be beneficial, but it is not required. Hydrogen and oxygen can be obtained directly from the lunar regolith (rock).

4. They are already discussing with other countries how to form an international partnership. The exact structure has not be solidified. And yes, they did announce they have started a dialog with CHINA.

As for “Mars First” advocates, there are a couple of reasons to go to the Moon first that do not rely on the lunar conditions being at all similar to Martian conditions. Primarily there is learning about the process of establishing a habitat elsewhere in a location that is somewhat easy to get back and forth in reasonable time. A Martian trip will take approx 6 months one way, without a substantial change in propulsion technology. That puts anyone going on an incredibly thin logistics supply line. It makes sense to try it first where access is a couple of days. Second, there are radiation exposure issues that need to be resolved for lengthy trips. Third, there is the ever-present concern over weakening due to extended periods in weightlessness. ISS is already working on that problem, and being under some gravity load is better than none, but it is critical we understand and can combat the effects if we want to protect the health of our astronauts.

I don’t know what open architecture you mean. Perhaps slide 13? It looks to me there’s a crew cabin (the ascent vehicle) that is a small canister and then a platform for a larger payload that could be an enclosed canister.