Comment by teachrdan
According to [0], there's about 2% water by volume in Martian soil, and you need to heat it up to 800 degrees Celsius to extract it -- which means you need a power source capable of generating those temperatures on an ongoing basis, which is unlikely without massive solar arrays that would be constant covered with (and damaged by) Martian regolith. Oh, and Mars receives less than half the sunlight Earth does due to its greater distance from the sun, and dust storms could obscure them for weeks on end.Or you could use hypothetical a nuclear power power plant that would be incredibly expensive to build, ship, run and maintain on a foreign planet.
You were right about the radiation! Kind of. There's "only" 50x more radiation on Mars' surface than on Earth's. You said this was less than what astronauts on the ISS are exposed to. How is that a meaningful comparison? You're talking about people living their entire lives in this environment, and presumably making babies who grow into adolescents and adults, all the while threatened by an amount of radiation we have no idea if a human child could live through.
The atmosphere on Mars is so thin that exposure to it will kill you. The level of radiation is so high that exposure to it will kill you, unless you lived essentially your entire life underground or in a bunker. The cold temperatures will kill you. The soil has perchlorate in concentrations that will kill you. There's basically nothing to do there -- no walks outside without a space suit, no nature to look at, no living beings (except perhaps soil microbes that would be instantly destroyed in the process of extracting water) -- nothing more available there than here on Earth except looking at the stars and dying. [1]
Every argument I've seen people make for colonizing Mars in the near term has been emotional. The arguments are all the more emotional for insisting that they are rational. We have no idea if we could grow food in a closed system indefinitely, or reproduce in space or on another planet, and the amount of research going into these literally existential questions is close to zero. Nor do the billionaires who claim to be obsessed with getting us to be a multi-planet civilization seem to give a shit about them. Colonizing Mars isn't a plan; it's a meme.
Finally, there's no thought given to how to deal with inevitable social problems that will arise if there are large (1000+) populations away from Earth: what to do with people who have psychological breakdowns? how do you prioritize if more people need to be sent home than there's space for on a return rocket? what are your responsibilities toward colonists who need expensive permanent care? what if they can't survive Earth's gravity due to physiological changes from growing up off-planet? What if an entire space colony will never be self-sustaining and they need to be supported with expensive shipments of food and supplies from Earth forever -- who will pay? Or will we?
Look, if you want to colonize Mars or other planets because you think it's a cool thing to do, at least that's an honest, personal opinion. But if you think putting a ton of resources into going to Mars anytime soon is a good investment -- when we aren't even mitigating an ongoing climate disaster here on Earth, the one environment to which we are exquisitely adapted and which is non-existent literally anywhere else in the known universe -- then you are fooling yourself.
[0] https://www.theguardian.com/science/2013/sep/26/nasa-curiosi...