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The Planetary Society BlogBy Emily LakdawallaMusings on the MoonSep. 18, 2006 | 11:09 PDT | 18:09 UTC
by Mark Adler
The Big Thing in the vision was the plan to send people to the Moon in preparation for sending people to Mars. Naturally, the first question to come up was: why the Moon? At first glance, it seems like a good idea -- sort of a stepping stone to Mars. However it would be extremely expensive to go to the Moon and would put off going to Mars for decades. Couldn't we just go straight to Mars with the people? Proponents for the Moon would say that we will practice on the Moon what we're going to do on Mars. The go-to-Mars-now proponents would say, hogwash, everything has to change for Mars since the environment and nature of the trip are completely different -- if the objective is to go to Mars, then just go to Mars. We have the technology today, why waste money and time on the Moon? Of course, both sides' arguments are a bit of a stretch. Going to the Moon will of course develop some things that will be needed to go to Mars, to work there, and to get back. At least it will if you're thinking a little about the long-term objective while you're making design decisions. The best example is the heavy-lift, Saturn V class launch vehicle that will be developed, now called the Ares V. Another example is the Earth entry and landing vehicle for the humans, previously called the Crew Exploration Vehicle, now called Orion. The Orion would require only some improvements to the heat shield to handle a landing from a Mars return trajectory as compared to a Lunar return. A significant benefit would be that we would (re)gain the operational experience of having people working on the surface of another body. And of course many of the subsystems, such as environmental control and life support, would carry over. But are all those really worth the cost and time of a Lunar campaign? You could just develop the launch vehicle and entry vehicle for Mars in the first place -- there is no magic there. Since we'll have to spend several months on Mars anyway for reasonable mission designs, then we can do our learning there for operations. We know enough about the Martian environment now to design robust equipment. Furthermore, a lot of the stuff you'd develop at great expense for the Moon would not be useful for Mars at all, such as the Lunar lander and return vehicle. There have been some silly arguments as well for the Moon, which I should mention in passing. One is that a Moon base provides a departure point for a Mars mission. Well, that's like deciding to jump into a giant two-mile deep pit on your long hike to a distant destination, and having to climb out again, instead of just walking around the pit. The deep gravity well of the Moon negates any benefit of stopping there. Another is that we can develop the ability to convert Lunar material into fuel, oxygen, or water, and that that experience will apply to Mars. Of course, the resource processing on Mars would be completely different, and would require new designs with almost none of the risk retired by the Lunar experience. The resource processing experience would be more applicable if we found water ice on the Moon and decided to land near water ice on Mars. Though in that case, chances are we could find some water ice on Earth to test the equipment with. Back to the more compelling arguments. Having worked on a surface mission, I'd have to say that there's a lot to be said for the operational experience that would be gained at the Moon. Much of that learning would give us a huge leg up for a Mars mission. But even there, you'd have to ask: what is the incremental cost of a second human mission to Mars compared to the entire Lunar campaign? If we had to go Mars the first time to get the operational experience in order to make the second trip more productive, that wouldn't be so bad. I'm sure it would be cheaper than the extra expense of going to the Moon. And you'd get another Martian landing site out of the deal. My diatribe so far sounds like I think you shouldn't go to the Moon first. Well, in fact I think not only that you should, but that it is necessary. Here's why. Let's say that you've asked NASA how much it will cost to send people to Mars. They give you an answer. Would you believe it? Heck no! Any sensible manager would look at the recent history of NASA's large programs, such as the shuttle and space station. The conclusion is that there's no reason to believe that the massive increases over the originally estimated costs would be any different this time. Furthermore, there are too few examples and too many differences to derive a simple multiplier from those experiences to apply to the Mars cost estimate. Any arguments about external influences, changes, international cooperation, etc. on those programs would be dismissed by the sensible manager. All of that will apply to the Mars endeavor as well. So there's no way to know what it will cost. Not a good way to start a project. Now you ask NASA if they have the management ability to pull together what it takes to succeed in something several times bigger than Apollo. Can they mobilize industry, establish the right partnerships, establish and enforce the necessary and sufficient lines of communication in a complex technical project, and resolve a dozen other organizational issues to meet schedule and cost and have safe and successful missions? If NASA said yes, we can send people to Mars now, just give us the money, would you, the sensible manager, believe them? Heck no! So what do you do with someone whose performance you are unsure of? Well, you give them a smaller job and see how they do on that before you risk far more on the larger job. You give them a job roughly the same magnitude but a little bigger than jobs they've had before, and with some similarity to the job you eventually want them to do. Then they will both learn and demonstrate the managerial skills you want to see. If the job is similar enough, they will begin to build the infrastructure that will be needed for the bigger job. Especially if you tell them what the bigger job is and that they'll get that bigger job if they do good on this one. Furthermore, having done the smaller job, they'll have a far, far better idea what the bigger job will cost.
That's is exactly the position that the US administration and congress are in, if they want to send people to Mars. Our government, in stunning contradiction to many other things they do, have done exactly the right thing by having NASA send people to the Moon first. If we could run the experiment in two parallel universes, I would predict that the skip-the-Moon universe would actually run into far more delays and it would end up being more expensive to get to Mars (if we got to Mars ever), than in the universe in which we go to the Moon first and then Mars. Let's say, for example, that the Mars program is estimated to be four times the cost of the Moon program. Then I might imagine I could save 20% by not going to the Moon. However not having that experience of going to the Moon first could easily increase my cost overruns by much, much more than the 20% I thought I was going to save. Ok. So we should send people to the Moon first if we want to send people to Mars. That leaves an open question. Should we send people to Mars? Or more precisely, at what price is it worth sending people to Mars? I'll leave that as an exercise for the reader. :)
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