I’ve allowed myself to get sucked into a discussion in comments over at Marsblog, and decided it made more sense to post about it here. There are a lot of misconceptions about the president’s Vision for Space Exploration (and they may actually be deliberate strawmen by those trying to twist it to their own ends).

Foremost among them is that the plan is to go to Mars via the moon, with the implication that everything that goes to Mars will therefore have to first go to the moon. Having established this as a fact, it is then blasted by some as a proposal to “build Cape Kennedy on the moon,” which is obviously ridiculously infeasible and expensive. It was the basis of this so-called argument by “Mark” against using the moon to get to Mars.

I believe the figures in the book demonstrate that the deltaV to get from LEO to moon is higher than that of getting to Mars. This is due to aerobreaking [sic] I think. Thus, even if there are prepaired [sic] fuel tanks waiting for you there for free, it’s more expensive to stop off at the moon. I could be fudging this as I don’t have the book in front of me.

He assumes that everyone going off to Mars “stops off at the moon.” If that were the case, then the relative delta Vs would be of interest.

But it’s not. This is nonsense, of course, and not what the president proposed.

What the president proposed was using the moon as a place to learn how to operate on another world, much closer to earth in case something went wrong, and looking into the potential to get resources there that could help go to Mars, particularly propellants. Propellants for a Mars expedition have to come from somewhere. They can either come from earth, by launching them from earth to LEO or L1 or some other staging point, or they can come from the moon.

If launch costs are such, and the ability to mine ice on the moon are such, that it’s cheaper to get the propellants from the moon than from the earth, then this is what will be done, and it has nothing with “stopping off at the moon.” It is simply logistics.

And no one can say with certainty a priori what the answer to that question is (including Bob Zubrin). We will only know after years of studies and initial robotic exploration, which are only starting to be performed now.