Sorry, my answer no longer applies, did you change the question? Or maybe I misread it.
For a breathable atmosphere you are talking about thousands of years probably, most optimistic 1000 years.
But for self sustaining colony - well that depends on the technology. But if not depending on a breathable atmosphere - doesn't have to be on Mars, could be anywhere. Mars really doesn't have much by way of resources over what you get in NEOs or the asteroid belt. It does have CO2, true - but that's at such low pressure, that it's a case of pumping it from a vacuum into your habitat. And anyway CO2 is usually what you have too much of in a habitat and try to get rid of.
The CO2 could be used for fuel on Mars. But there are lots of ways of getting energy and fuel in the solar system - including e.g. on the Moon we'd use solar power, or nuclear power - it's a minor plus, ingenious, idea true, useful on Mars if you've already decided to go there - for robots also - but not really a major reason to go to Mars rather than, say, NEOs or the Moon.
So, we need to sort out a self sustaining colony, meaning one that can feed itself. Biosphere 2 was heading in the right direction, also Russian experiments with generating oxygen from algae.
But nobody has done it yet, especially in space conditions, not fully self contained.
If we can do that, it will massively reduce supply issues. Imagine the ISS with no need to send supplies there from Earth - and if we can also figure out how to keep crews healthy there for years on end? It would cost a tenth or a hundredth of what it does now.
So - that's the big question I think - can humans stay healthy and do so in a reasonably self contained habitat without resupply from Earth? If they can we could set up settlements almost anywhere in the solar system. If not, we'd struggle to do it anywhere, Mars included. And surprisingly, NOBODY is doing practical research on this at present. There isn't a single human occupied spacecraft or proposed spacecraft or habitat by any of the major space agencies to explore this topic. Not even much by way of ground experiments either - since the Biosphere 2 and the early Russian experiments, seems to have been forgotten, certainly not hit the science news.
I really don't understand why they talk about human colonization and yet have human factors such as closed system habitats, and artificial gravity - right at the bottom of their list of priorities. Simple experiments to research into human factors, that cost millions rather than billions, just don't get done, and haven't been done for decades now.
Here I'm also thinking about artificial gravity experiments, Jo Carroll has suggested that we fly a simple tether experiment, costing only millions, to test artificial gravity and make it possible to design future spacecraft and space stations based on knowledge of what humans need by way of gravity. But - it's never flown, never been more than just an idea on paper. Why?
That's relevant to Mars also, nobody knows if humans can survive long term in Mars gravity - or what happens to humans in those conditions - we could have run years long experiments in Martian gravity 40 years ago but never have done it. Why not?
If the decision makers in the space industry were really interested in human factors, the space agencies should have done that and run with the idea, or come up with something else better themselves if they have other ideas. But no, it just gets ignored, just go back and forth to the ISS doing essentially the same human factors in zero g experiments over and over.
And the private sector seems no better - at least could be that Elon Musk is doing a secret program of human factors research, into artificial gravity and closed systems - but if so has said nothing about it. Mars One have said they'll research into it but not seen any evidence of a major program to solve these issues.
It's like - as ideas, they are interested in sending humans to other places outside of Earth and LEO, but when it comes to research, all they are interested in doing is researching into how to send more and more heavy rockets to other places in the solar system,.
For a breathable atmosphere you are talking about thousands of years probably, most optimistic 1000 years.
But for self sustaining colony - well that depends on the technology. But if not depending on a breathable atmosphere - doesn't have to be on Mars, could be anywhere. Mars really doesn't have much by way of resources over what you get in NEOs or the asteroid belt. It does have CO2, true - but that's at such low pressure, that it's a case of pumping it from a vacuum into your habitat. And anyway CO2 is usually what you have too much of in a habitat and try to get rid of.
The CO2 could be used for fuel on Mars. But there are lots of ways of getting energy and fuel in the solar system - including e.g. on the Moon we'd use solar power, or nuclear power - it's a minor plus, ingenious, idea true, useful on Mars if you've already decided to go there - for robots also - but not really a major reason to go to Mars rather than, say, NEOs or the Moon.
So, we need to sort out a self sustaining colony, meaning one that can feed itself. Biosphere 2 was heading in the right direction, also Russian experiments with generating oxygen from algae.
But nobody has done it yet, especially in space conditions, not fully self contained.
If we can do that, it will massively reduce supply issues. Imagine the ISS with no need to send supplies there from Earth - and if we can also figure out how to keep crews healthy there for years on end? It would cost a tenth or a hundredth of what it does now.
So - that's the big question I think - can humans stay healthy and do so in a reasonably self contained habitat without resupply from Earth? If they can we could set up settlements almost anywhere in the solar system. If not, we'd struggle to do it anywhere, Mars included. And surprisingly, NOBODY is doing practical research on this at present. There isn't a single human occupied spacecraft or proposed spacecraft or habitat by any of the major space agencies to explore this topic. Not even much by way of ground experiments either - since the Biosphere 2 and the early Russian experiments, seems to have been forgotten, certainly not hit the science news.
I really don't understand why they talk about human colonization and yet have human factors such as closed system habitats, and artificial gravity - right at the bottom of their list of priorities. Simple experiments to research into human factors, that cost millions rather than billions, just don't get done, and haven't been done for decades now.
Here I'm also thinking about artificial gravity experiments, Jo Carroll has suggested that we fly a simple tether experiment, costing only millions, to test artificial gravity and make it possible to design future spacecraft and space stations based on knowledge of what humans need by way of gravity. But - it's never flown, never been more than just an idea on paper. Why?
That's relevant to Mars also, nobody knows if humans can survive long term in Mars gravity - or what happens to humans in those conditions - we could have run years long experiments in Martian gravity 40 years ago but never have done it. Why not?
If the decision makers in the space industry were really interested in human factors, the space agencies should have done that and run with the idea, or come up with something else better themselves if they have other ideas. But no, it just gets ignored, just go back and forth to the ISS doing essentially the same human factors in zero g experiments over and over.
And the private sector seems no better - at least could be that Elon Musk is doing a secret program of human factors research, into artificial gravity and closed systems - but if so has said nothing about it. Mars One have said they'll research into it but not seen any evidence of a major program to solve these issues.
It's like - as ideas, they are interested in sending humans to other places outside of Earth and LEO, but when it comes to research, all they are interested in doing is researching into how to send more and more heavy rockets to other places in the solar system,.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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