[Grishnakh]

>someone should go out there and try to set up a self-sustaining colony on the pole or in the middle of a desert.

>That's already been done. It was called "Biosphere II", set up in the Arizona desert. It failed.

>An experiment is only a failure if you don't learn anything from it.

It was a failure. Go back and look at what I replied to: the OP said someone should go set up a self-sustaining colony. That was attempted with Biosphere II. It failed. It was not self-sustaining.

It they learned stuff from it, that's all well and good, but it doesn't meet the requirement from the OP of being self-sustaining.

The OP says we should set up a self-sustaining colony on Earth as practice for something in space. We have not done that. We tried and we failed, and we didn't bother trying again. So the point here is: what makes us think we can set up a self-sustaining colony on Mars when we can't even set one up in Arizona? Cart before the horse.

[jpindar]

You appear to be thinking of it as an attempt to set up a colony, whose purpose was to be a colony (or a simulation thereof). It failed at that, sure.

But it can also be thought of as an experiment whose purpose was to test the hypothesis "this is a good way to set up a colony". In the scientific sense of the term, experiments that disprove their hypothesis are as successful as those that prove it. A failed experiment is one that is inconclusive or incomplete.

[Grishnakh]

You seem to be thinking of it as a scientific experiment. I'm not. In the context of the OP's comment, I'm thinking of it as a "trial run", to see if we can figure out how to build a self-sustaining colony here on Earth, where it's safe and we can cut the "simulation" short if there's a problem and try again, before we try it for real on another world. In that context, we failed. We did not set up a self-sustaining colony and prove that we can do such a thing successfully. Perhaps we could be successful if we tried it a few more times, but we have not been successful yet. Therefore, we are unprepared to attempt any such project on another world.

Building a habitat on another world is not a scientific experiment; it's an engineering project.