I tend to agree with many others that all one way or the other or even 50/50 is simplistic.
Further to that I have some other thoughts. I am a big space fan ever since I heard Sputnik from orbit beeping at us, watched the first few Americans in space, John Glenn and all of other Mercury and Apollo programs...
So... what I say may not be popular and might seem out of place for such a forum, but I do think men in space are largely a detriment to efficient exploration of it, and far more knowledge can be gained by the likes of Cassini, Galileo and Hubble and the like, than mere "Boots on the Ground" and flag planting ceremonies. It is all bang for the buck...
Further I have other ideas that may not fit well for some, but I hope it provokes thought and a decent debate, and is not just a bunch of back slapping and agreement. I would hate to see a bunch of money spent on sending people to Mars so we just cross it off our list, saying, "Been there, Done that, now we can cross it off our list for another 50 years", like has happened with Apollo.
A few points...
I don't remember if many long term studies were done 40 years ago to "prove" men were able to survive the trip to the moon. We sent them anyway. Back then there were only 3 or 4 billion people on this planet, now there are about twice as many. Many say here they would volunteer in a heartbeat if they were given the opportunity to go to Mars. I think likely the first humans to go to Mars may not make it back, but if they do, they will not last long. I suspect that after they spend 6 months getting there and a month or so in 1/3 gravity and another 6 months or so returning... they will likely be barely able to stand up on Earth again before they succumb to radiation sickness. But they will have tried, I hope, knowing the risks involved.
I agree with many others that these experiments where we simulate a trip to Mars by locking up some candidates in a pseudo Mars craft, show little about what may happen. The group of candidates that do these tests are what determine if they are successful or not. Replacing any one of them of several may totally change the outcome. The knowing that you are still safely on this planet and could issue an alarm that let you out of it in minutes is always an option. A better test would to be in a situation a few kilometers under the ocean knowing that if ever the pressure containment failed, you would be instantly incinerated as the adiabatic effects would instantly raise the temperature a few thousand Kelvins, let alone begin a bad hair day...
To be truly relevant, for such experiments, I would say you would need to also add a CAT scan each day, or inflict a full body X-ray every hour or so, to mimic the effects of the situation on the participants, with their knowledge, of course, so they have something real to stress them out. This is otherwise little more than flagpole sitting if the real hazards are not properly inflicted on the subjects.
I won't echo folks from a hundred years ago that said that if God meant man to fly he would have given us wings. And, nowadays, I would have to say that if God meant we should go live on Mars, then He would have adapted us to a lack of gravity, and made us impervious to cosmic radiation and solar flares. That is heresy and politically incorrect in such company as here, however true it may be.
I still feel some problems with many that say we MUST leave Earth to better our chances of survival as a species, and that unless we leave Earth we will be destroyed by some big rock, that only by hurrying up to get our boots onto some other planet we are all doomed. Really? If the Big Rock from Space means that The Sky is Falling, do you really think human civilization will be preserved if there are a few survivors on the Moon and Mars? We lose much if that happens, but I don't see how human culture is necessarily preserved because we abandoned a few people on Mars or the moon during the next few decades. Great Sci-Fi themes, but not paid for well by book sales.
I question the whole premise that a 20 mile rock would wipe us out as a species forever. I could see that we may lose all but a fraction of a percent of the current population in the worst case, but 6 billion lowered to a few million is not a complete wipeout. The gene pool is still there, but may be widely spread.
To say we will, of course, suffer the fate of the dinosaurs is evidence that those that think that are not much smarter than they were, and deserve to be wiped out. I am tired of people saying my survival skills as an individual or ours as a species are no better than some big lizards 65 million years ago! If they think they are that helpless then I suspect they WILL be in the 99% that could be wiped out.
There are no nice planets in this solar system that would also welcome human life like Earth has done. We are a very long way from even IDENTIFYING a good a planet in some other star system that would be another replacement for Earth. And once we find one, it will take us centuries to get there and make friends with the natives and establish anything that looks like our current civilization that we have here.
In the meantime, we are better off identifying threats to this planet, and trying to implement ways to thwart them. Some real research into how to prevent an asteroid hitting us at all would be far more productive than walking about Mars for a week or two and not going back for several more decades. I also think we need a paradigm shift from basing our society of the consumption of non renewable resources to a form of true sustainability. To tell me that we need to colonize Mars or the moon or Europa to survive the next several million years is at best foolish, and at worse, one of the biggest Fairy Tales we are being fed. To say, further, that we inevitability shall so pollute or ruin this planet, and therefore need another to move to survive is defeatist thinking that I hope is wiped out if the big rock does come.
I realize my view is not popular with many other true space fans, but I am sorry if I don't march to the same drummer as others do. I am a keen fan of space exploration, and few can say they are more so. And I welcome any one to try to tell why what I think is wrong. Feel free to read my profile if you think I should worship someone's sacred cows, or that I am not willing to point out the Emperor has no clothes.
I hope others can respond and either agree or disagree on the merits of the arguments. I cannot see how us putting boots on the ground gets us much more than dusty boots on some place we will never stay long on. Robots like Cassini and hubble last longer than most astronauts' careers do. They provide more data for use to analize than we are willing to pay for the help to do so in real time. We will see things in pictures that Hubble took years ago that we haven't got the human 'manpower yet to keep up with.