The one-way-to-Mars idea has been around a long time, and as someone who ended his book on Mars with a section on the various ways in which making the voyage to that particular "other world" could be seen as chiming with the idea of making the voyage to the undiscover'd country of death I have a sense of why it might appeal. But even when it is championed by someone as smart as my friend Paul Davies, as is the case in today's Guardian, it is still a silly idea. Here are extracts from Paul's article with my comments
Well you can make do without a return vehicle, sure. At the same time, you have to take or pre-position four years of supplies if you are to keep a straight face about "not talking about a suicide mission" -- two years to take you to the next resupply mission and two years to deal with the possibility that that resupply mission might fail. You have to take either more shelter or more tools for building shelter. You have to take a long term power supply -- either a lot more photovoltaics than a short-term mission needs or a nuclear reactor. Again, if you are to say "not a suicide mission" with a straight face, back-ups for everything. And you still need to design a wholly new, large capacity entry, descent and landing system, which is a big challenge, and sort out how to stay ready-to-explore healthy on the trip out. The idea that leaving out the return vehicle could in itself reduce costs by 80% seems extremely farfetched -- even more so when your plan includes prepositioning the supplies and food. Why not preposition the return vehicle too, a la Mars Direct? Would that really increase the costs fourfold?
Most importantly, in terms of costs, there's the ongoing commitment. A set of Mars missions you can cancel is a much more attractive proposition than a set of Mars missions that you cannot cancel without killing people ("Launch the next rocket or the kid gets it"). To fund a single one-way-to-Mars mission is more or less to sign up to funding them for as long as the colony lasts. That is a far larger spending commitment than required for a small number of return trips.
(Minor aside: no-one cares more about methane on Mars than I do: but does it really make Mars more habitable?)
This carries a whiff of the idea that the colonisation is being done by underpants gnomes (not a bad idea: they'd use up fewer expendables), with "profit" in the archetypal UG business plan replaced by "self-sustainability". How and why should we believe that the colony would become self-sustaining? And how much extra investment would that take? It is worth noting that Antarctic colonies, 50 years on, are not self sustaining. And Mars is a lot tougher. Not saying it couldn't be done -- but it doesn't sound cheap. You have to keep resupplying for a century at least, probably at an increasing rate for much of that time. If aiming for self-sustainability were a useful goal in such circumstances, we would be trying to make McMurdo self sustaining. We're not.
And that's before we get to the pregancies. No one at present has any idea of what it might take to carry a child to term under Martian gravity, or whether a non-engineered human can actually do such a thing successfully. That's a pretty big known unknown to sweep under the table. Is the plan for people just to get pregant and see what happens?
Yes, it might -- if the colony has the capacity to get them out from the depths at which they probably live (ie heavy-duty mining equipment). But the colony would also fatally compromise any possibility of making the research biologically reversible, which carries a strong environmental penalty over and above the fact that the contamination involved might make all that science a little hard to do.
I accept that arguing from science fiction is not ideal, but bear in mind the early Larry Niven stories in which Mars is an unexplored backwater largely because asteroid miners see no reason to ever descend into a gravity well. If asteroid mining ever makes sense, wouldn't it make most sense to target near-earth asteroids, of which there are plenty, rather than main belt asteroids? (Also, I suspect that in terms of travel time rather than delta v the average main belt asteroid is not that much easier to get to from Mars than from Earth orbit, but I may be wrong)
Really? All humanity? A cataclysm that would mean that the earth-bound survivors were fewer in number than a colony on Mars suggests to me either an extraordinarily thorough-going cataclysm or a really large colony on Mars, and neither of those seems very likely. Certainly seems beyond the power of war or disease, and I'm not sure even Chicxulub could do it (New Zealand flora were not hugely affected by the K/T event). Also note that having detoured through the Mars-as-a-trading-partner idea, we have now returned to the Mars as self-sufficient outpost idea -- a Mars robust enough to have all links severed is a Mars less reliant on earth than the Greenland colonies were on Iceland and Scandinavia. (Also, there's a philosophical point here: if all but a handful are dead, does the continuation of the culture as an idea really matter? Is it that much more than its instantiation? And does the answer to this change if the genocide was self inflicted?)
Leaving aside that our species didn't walk out of Africa (a few did, a lot stayed), the symbolism here is terrible. While Paul is definite that this would not be a suicide mission, it would involve a great deal of death and a high risk of total failure (especially if being done on the cheap). As Paul says, there will be "reduced life expectancy due to radiation, lack of advanced medical resources" as well as a very high risk environment: as Greg Benford once put it to me "Like the moon, but with worse weather". I was going to write at this point that human sacrifice is not an acceptable instrument of policy, and then realised that of course it is. But in such a blatant form I can't see it flying. The fact that there are plenty of people who might volunteer, as Paul rightly says, does not mean that it would be right to indulge them.
And what if they live? They do so because of unparalleled spending. A world where a select few gets hundreds of millions, at the very least, invested annually merely to keep them alive while equally deserving people die in large numbers for want of far less is not a very attractive place.
Human Mars exploration is indeed a fine goal, and it is quite possible that fairly early on there will be some who elect to stay. But the only real argument for doing it sooner or rather than later is the selfish one of wanting to see/participate in it personally. I can appreciate that, but I don't think it's a compelling policy point. There are a lot of other big exciting projects to inspire us -- a new energy infrastructure for the world, the millennium development goals, in pure science the development of telescopes for characterising the atmospheres and possible biospheres of exoplanets.
(This post doesn't mark any long term intention to start blogging here again in a serious way; I am in fact somewhat surprised to find myself putting it up, since there has been so much good stuff about Mars I haven't blogged. I guess I felt I had something to say. More frequent, less Martian blogging can now be found over at Heliophage.)