Here's the day's final repost of an old blog post about space policy. This is yet another post from 2004, with the usual caveats about linkrot and dated numbers and the like.
This one is more or less a direct response to comments made in response to the previous post attempting to argue that using the Moon as a step toward Mars isn't a priori idiotic. Again, I'm not sure how successful this is, but you can judge for yourself:
In the comments to the previous post about the Moon/ Mars proposal, Jake McGuire raises a number of interesting points, which deserve a full response. Having sat on that response for several days, I may as well spin it off into a separate post.
In every way which I can think of, if there's an aspect of the Martian environment which we can't simulate in LEO or in a Mars Chamber on Earth, the Moon is different from Mars in ways that matter a great deal. We can simulate landing on another planet on Earth - just turn off the GPS receiver and barometric altimeter, and strap on bigger rocket engines. They run satellites through thermal vacuum chamber tests on Earth, and it would be easier to simulate the Martian environment in one than on the moon. We can stick three people in an off-road RV and have them drive around for a month to test EVA planning procedures for a million dollars here; to do the same thing on the Moon would cost hundreds of millions, and still wouldn't point out issues with actual Mars EVA hardware, because you can't use Mars EVA hardware on the Moon. And since most of the cost of a Mars mission is going to go into designing the hardware and software to go there, if you have to design different hardware for the Moon, you have to ask what you're really gaining.
I have two basic responses to this. One is just to note that the "safety net" factor of the relative closeness of the Moon weighs pretty heavily with me. Going directly to Mars is very much like flying without a net, and before we go trying that, I'd like to see us get a lot more practice running manned missions beyond low Earth orbit. (After all, we're hardly batting 1.000 on sending robots to other worlds...) Missions to the Moon offer the chance to do that, in a situation where something might conceivably be done should disaster strike. I wouldn't want to gamble the whole manned space program on one mission to Mars.
(There's also a decent case to be made that there is interesting science to be done on the Moon. Granted, it's not particularly sexy science (though the telescope idea is kind of cool), but as multi-billion-dollar science projects go, it's not really any less practical than another whopping huge particle accelerator.)
The second response I have is, in many ways, the more fundamental of the two, and goes to the question of what, exactly, we're going to Mars for. If we're doing it as an Apollo-style proof-of-principle mission, then there's no real reason to mess with the Moon first. If Mars is the only goal, then it makes sense to spend the minimum possible amount, and just go to Mars. If that's the goal, going to the Moon would be a waste of time and money.
On the other hand, if this is really intended as a first step toward a permanent human presence beyond low Earth orbit, I'm not so sure it's a bad idea. Yes, going to the Moon doesn't provide that much direct help in getting to Mars, but it does get humans into space, and working in a different environment, and if this is really a part of a long-term program of manned exploration, we're ultimately going to want as much experience as possible in many different sorts of off-Earth environments. In the context of a decades-long, multi-trillion-dollar push into space, a few extra billion on Moon missions is nothing to complain about.
(This is, of course, in the Infinite Money Limit world in which everybody agrees that a manned space program is a thing worth spending sizable sums of money on, and spending that money doesn't cripple anything else that we're trying to do. It is manifestly obvious that we do not live in such a world, but as in the last post, I'm going to pretend that we do, as a purely academic exercise in discussing the technical merits, goals, and aspirations of such an idealized manned space program.)
To justify this, I need to clarify my views on what "permanent human presence" means, here. I'm not talking about what I called the "Paranoid Chicken" theory of space exploration in a previous post, of trying to start as many colonies as possible before some sort of inevitable disaster wipes out all life on Earth. While I wouldn't go as far as Bruce Sterling does in dismissing colonization, I don't have much regard for this view. Establishing a self-sufficient colony on another planet, even a relatively hospitable one, will be a project of a great many years. "Self-sufficient" here means "able to continue normal operations even after the Earth goes kablooie." That's not just a matter of producing food and air and water-- those are relatively trivial-- it also requires the infrastructure to keep everything running with locally produced resources. Which means mining and smelting metals, manufacturing computer chips and other electronic objects, extracting and refining something to serve as rocket fuel, etc. For any technology on this side of Eric Drexler's loopiest nanotech dreams, this is a gigantic undertaking.
Getting any really substantial number of humans set up on another planet will probably require some sort of terraforming project (and years of tedious debates about the ethics of such a plan), to get to the point where space suits and airtight habitats are no longer required. Not to mention the problem of just shifting enough bodies into space to have a viable population. This isn't anything that's going to happen any time soon, certainly not soon enough to make it the exclusive focus of a space program. Luckily, I don't believe there's any particular urgency about it, either.
There's another way to go, though, which is to recognize that interest in other planets will remain primarily scientific (rather than commercial or imperialistic) for years to come, and treat it that way. The focus then is on treating manned bases not as the beginning of off-world colonies, but as research stations. They needn't be small, sealed tin cans-- people will be spending months if not years there, after all, and any decent research program will involve a sizeable number of people to support it-- but it's not necessary to build cities, either. Space bases can be something like Antarctica, only much farther away, and tremendously harder to reach. But there's nothing particularly wrong with that, because space is also infinitely more interesting than Antarctica.
And if take that kind of approach, Mars really isn't an end unto itself. It's just the closest point of significant interest. But, really, there are plenty of other interesting places to go, and plenty of other interesting things to see. Once you can put people on Mars on a regular basis, and build up some sort of permanent presence there, Jupiter's a pretty interesting place to think about going look at, and its moons provide enough variety to keep generations upon generations of scientists occupied. And, of course, we know next to nothing about the asteroid belt, or Venus, and everybody knows the alien monolith is really in orbit around Saturn...
Self-sustaining colonies anywhere off Earth are so far off in terms of the technology needed to make them work that they're hardly worth worrying about. Permanent bases on Mars and the Moon are not-- those are within reach in a reasonable time scale. And human exploration of the rest of the Solar System is comfortably to this side of self-sustatining colonies. If you want to start setting lofty but reasonable goals for manned space exploration, that strikes me as more reasonable than talking about colonies as an insurance policy against Earthly disaster.
(Yeah, it'd be cheaper to explore the rest of the Solar System by sending out a zillion tiny robots to do it for us. But somehow, that just doesn't compare to having humans there on the scene looking at it....)
If you want to go that route, you don't necessarily want to strike directly for Mars. A fast manned mission to Mars risks being another Apollo-style game of planetary tag: great PR, quickly abandoned when people get bored. To set up a real, permanent presence in space, you want a broad, slow, incremental approach. You want to build up a large base of experience and infrastructure, so that each mission supports further pushes. (And, to interrupt this pie-in-the-sky dreaming for a little corrosive cynicism, the more you build in space, the harder it is to retreat... A few flags and some miscellaneous junk are easily abandoned. A manned base on the Moon is harder to cast aside. Note the reluctance to cast aside the ISS, which is actually pretty much useless...)
(Why the Moon rather than a gigantic rotating space station at a Lagrange point? Because years of mucking about in orbit have demonstrated pretty conclusively that living in free-fall sucks. If we're going to put people in space on a permanent basis, we're going to have to put them in places with gravity. Which means planets and moons, so why not focus on that from the start, rather than spending years of constant work in free-fall to generate a giant simulation of a planet or moon?)
Is this grand vision the sort of thing you can pull off at $10 billion/year? Sure, if you're willing to spend enough years at it... Obviously, this would require more funding at some point down the road. But $10 billion/year, spent right, could make a start at it, finding a replacement for the Shuttle, and making the first steps toward getting back to the Moon.
The bigger problem is one of leadership. Even a basic Mars mission would require a solid commitment to the manned space program over a decade or more, in the face of the inevitable setbacks, political shifts, and complaints that the money would be better spent somewhere else. Those qualities are even harder to come by in Washington than money. But it's a lovely dream...