All of this can be done today in the Sahara, or underwater, or on the top of K2, but nobody has done them there. Why should Mars be any different?
Yes, one can do these things, but will the economics work out such that it's actually feasible? For example, solar power on Mars is pitiful, and there are no fossil fuels. Where does the power for industrial production come from? Nuclear reactors? How expensive is it to bootstrap a reactor on another planet? Where does the coolant come from without a nearby river?
The Sahara lacks a CO2 atmosphere, it also lacks substantial quantities of subsurface ice.
Besides which, about 4 million people live in the Sahara today, despite many of the surrounding countries being some of the poorest and least developed on Earth.
The point of living on Mars is not to find the most convenient place possible to live. That would not be Mars, nor would it be the Sahara, nor would it even be Copenhagen, Dubai, or the Netherlands (where 10 million people live on land that used to be under the sea). But people live in those places even so because it turns out there are compelling reasons to live there. Just as, I believe, there are compelling reasons to live on Mars (much more so than in living in the Sahara).
Edit: most people living in the developed world today are swaddled in the embrace of a vast web of advanced technology and industry. The hammer used to build the home down the street was mined and forged an ocean away. The phone you use every day contains components developed and manufactured across a handful of continents. The food you eat could come from next door or across the world. But that web of technology and industry is familiar to us, whereas one involving living on Mars is alien and implausible to our sensibilities. But over the course of decades and centuries as technology advances, as industry develops, as the unusual becomes more commonplace, maybe people will start to view life on Mars in a similar fashion. Maybe it won't seem so impractical when the bounty of martian agriculture feeds substantial populations, when martian industry is a multi-billion dollar or multi-trillion dollar business, when cities full of people exist on Mars, and so on.
Wow, my creative mind is tingling with ideas of what this could lead to. Martian politics? Martian colonies rebelling and forming their own 'nation'? Race and gender issues on Mars? Possibility of wars between Earth and Mars over the most easily accessible resources? Arms race? Etcetc... whoa!
Because Mars can 1) support a large human population, with industrial infrastructure, and 2) is situated closer to the majority of the resources of the solar system. It's a foregone conclusion that if humanity gets off the Earth, that Mars will be a future economic superpower.
(The middle of the Sahara and certain places underwater may also become settled for similar reasons: proximity to natural resources. K2, not so much.)
> solar power on Mars is pitiful, and there are no fossil fuels. Where does the power for industrial production come from?
The economics of solar power are completely different for Mars.
Given that Mars is about 1/10th as massive as the Earth, launching from its surface to space is vastly cheaper. In fact, the reduced gravity on Mars is forgiving enough that we can contemplate building a space elevator there with materials that are currently commercially available.
I'm not convinced Mars can support a large human population even with initial massive economic subsidy. Pregnancy in the high radiation and low gravity of Mars may result in low fertility rates and some very... interesting, (misshapen, if not defective) new humans. Unfortunately the only studies, which were kind of bad, were conducted in zero G and not 0.4 G [1], and the embryos were quickly transferred into mice in 1G for neonatal development and birth.
Even if fetal development in microgravity is OK, absent DNA repair technologies, radiation induced decay of the gene pool over the generations may require a continual replenishment of fresh, "unmutated" DNA from Earth--at least until humans evolve sufficiently on Mars. It is not practical to assume no additional radiation exposure on Mars: even if humans are buried underground, and do not come out during the occasional solar storm, they must occasionally walk on the Martian surface. Otherwise it's a robot's world, and human colonization is merely an exercise in preserving the human race though Martian burial in case of Earth apocalypse.
> radiation induced decay of the gene pool over the generations
Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3.
Low gravity might be an issue. Given the record on biological processes we thought earth-normal gravity would be vital for, I doubt it, however. I did find one mention of lower fertility rates from microgravity.
> Exercise: think of inexpensive ways of mitigating this. Took me about 2 seconds to think of 3.
instead of "leaving it as an exercise to the reader", why don't you list your three cheap ways to mitigate gene pool decay? coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg.
> coz i can't see any cheap ways - anything coming from earth will cost an arm and a leg.
Good point: Relatively inexpensive.
1) Zygotes, sperm and eggs are very small. Even with radiation shielding, it's not that expensive to ship a whole lot of them from Earth. These can be used to "refresh" genetic information from Earth and ensure enough genetic diversity. If medical technology has progressed far enough, it may even be possible to send sequencing data and avoid shipping material altogether.
2) Keep everyone born on Mars underground and shielded from radiation, at least until they can store their genetic material in radiation immune facilities for breeding later.
3) Everyone immigrating from Earth would be wise to store and ship their own genetic information. This can be sent on the same flights with the "backup diversity" information in (1), which would greatly minimize the cost. The marginal cost for another sample of eggs/sperm is going to be pretty low.
Also keep in mind that not every launch has to contain such information.
For example, if the fertility rate is lower (but not zero), you can try a "quantity, not quality" approach. My parents had like a half dozen siblings each; nowadays people only have one or two kids but they could easily try for more within a lifetime.
The simple answer about the Sahara is that's its (1) in our biosphere and (2) there are too many people about.
Part of the reason space is so attractive is because it's empty - land goes to who gets there, not who has force of arms to hold it, and there's a hell of a lot of it out there.
The other reason is, you can do whatever you want, and not endanger the lives, or livelihoods of other members of the human race. Toxic spills on Mars, or asteroids or in orbital foundries don't endanger anyone. There's a massive advantage to be had pushing heavy industry and mining off-world.
> land goes to who gets there, not who has force of arms to hold it
no, this will never be true, whether its mars or earth. Right now, the other planets isn't "claimed" because it's not economical, nor worthwhile (yet). I bet you when the sufficient incentive and technology exists to colonize another planet/moon, the various gov'ts will start claiming land, using the thread of force.
An unfortunate truth. Many settlers who came to the New World did so to escape persecution from the existing regimes in the Old World. But upon arrival, they created their own societies, cultures and governments that persecuted new groups of people.
I'm afraid that the saying "you can take the [person] out of the trailer park, but you can't take the trailer park out of the [person]" applies to all of humanity.
Yes, one can do these things, but will the economics work out such that it's actually feasible? For example, solar power on Mars is pitiful, and there are no fossil fuels. Where does the power for industrial production come from? Nuclear reactors? How expensive is it to bootstrap a reactor on another planet? Where does the coolant come from without a nearby river?