We have bases on Antarctica, and they're not self sustaining. Consider that Antarctica is far more liveable and closer than Mars.
I'm certain folks have tried on Antarctica (we've had constant human presence there for decades).
However, we still failed even under a much more controlled and hospitable environment - Biosphere 2.
Biosphere 2[1] failed because of our lack of understanding of our own ecosystems on earth. A minute imbalance led to the entire ecosystem failing.
The issue with Mars isn't getting there (or back) - government's have been doing this for more than a decade.
The issue with Mars is getting people there, alive... and keeping them alive for the duration of the mission, and then returning them home alive.
We're only now starting to explore the effects of microgravity on the human body - and having not figured out how to mitigate some serious issues (such as your eyes losing shape, causing you to go blind[2]), we're not going to be able to seriously consider long duration space travel, let alone inhabit another planet.
[1] https://en.wikipedia.org/wiki/Biosphere_2
[2] http://www.space.com/25392-manned-mars-mission-astronaut-vis...
Biosphere 2 was in many ways more challenging than Mars. It was intended to be totally self-contained with all water and oxygen recycled. On Mars, water can be found outside, and oxygen can be made from the atmosphere industrially.
The transit time to Mars with this system is 3-4 months. Astronauts have already spent far more time in orbit than that. There are negative effects, yes, but blindness isn't one of them (and your link doesn't even list blindness as a potential consequence, just impaired vision).
It's possible that the reduced gravity on Mars would continue to cause harm, but I rather doubt that it would be so bad as to make the whole venture impossible. Maybe Martians have bad eyesight and shortened lives, but nobody's doing this for their health anyway.
Nobody said they _had_ to, but I'm sure someone has tried over the years out of a scientific interest. (Although I have no source for this, so it's unsubstantiated unless someone digs something up).
> The transit time to Mars with this system is 3-4 months
Travel time depends on trajectory, however safe estimates usually are around 6 months each way.[1]
> It's possible that the reduced gravity on Mars would continue to cause harm, but I rather doubt that it would be so bad as to make the whole venture impossible
Well, the effects we're observing now (for the first time!) are largely from Scott Kelly[2]'s year in microgravity. Going to mars and back takes around 1 year's time (6 months approximately each way), plus we assume they'll stay on the surface longer than a few hours... so these may prove to be serious complications. The scary thing is, few talk about these issues when dreaming about traveling to Mars (Musk included, apparently).
[1] http://www.universetoday.com/14841/how-long-does-it-take-to-...
The figure I stated comes from the presentation we're discussing, I didn't just pull it out of my nether regions. You can go faster if you're willing to use more fuel.
You're "sure" that someone has tried to set up a self-sustaining colony in Antarctica even though you have absolutely zero evidence for any such thing, yet you completely reject a figure I got straight from the source material we're supposedly discussing here? I can't carry on a conversation like that.
We have yet to see if these figures are sound. Hauling enough fuel up there for an oversized vehicle quickly becomes an issue - the more weight, the more fuel required, which adds to weight.
Regardless, 3-4 months each way is still a long time in microgravity. I don't see the point you're raising.
> You're "sure" that someone has tried to set up a self-sustaining colony in Antarctica even though you have absolutely zero evidence for any such thing, yet you completely reject a figure I got straight from the source material we're supposedly discussing here?
The grand point I raised was we've tried this on earth, and failed. We understand earth fairly well, comparatively... yet we've failed each time we try. We can't just waive hands and say this isn't an issue.
I'm not talking about Mars anymore, because it would be fruitless.
A grand point that you have failed to back up with anything other than a hunch, and are defending by rejecting numbers, that while are far from infallible, you didn't give any reason for rejecting.
Maybe as a hobby idea. But has anyone seriously tried, with an 8-9 figure budget, a team of engineers, etc.? Shipping in supplies is cheap. There is little financial motive to make a self-sustaining colony.