Fixed. Mars is impossible, for now. We haven't kept someone in space long enough to reach mars nor have we developed a sustainable model that's extraterrestrially tested. Mars has more problems than a moon base, not significantly less (there's a few small pros and cons but being so far away is a major con).
> there is literally no reason to believe we couldn't accomplish it using current levels of technology
Except that we have no demonstrable way to do it, any fantasy seems plausible in comparison. At least try to start a closed biological system with a rat and find out how hard that is, then add the lag-time to service problems and a low gravity high radiation environment, etc. The movies have really poisoned the reality for the US population, but maybe it's part of the PR to raise money. I can understand that, but I won't concede that it's doable yet.
A quick google search says a trip to mars varies between 150-300 days. The longest human spaceflight exceeds that at 438 days aboard the Mir space station [1] from 1994-1995.
1. http://www.space.com/11337-human-spaceflight-records-50th-an...
See e.g. http://www.mars-one.com/faq/health-and-ethics/how-much-radia...
But this is pretty basic for any Mars trip. I'm sure it's been considered.
I'm not one of the nay-sayers. Musk has a good record of getting things done, although sometimes maybe he pushes a little too hard.
I certainly don't think "That's s stupid waste of time and money."
And if Musk doesn't do it, someone else will.
> We haven't kept someone in space long enough to reach mars nor have we developed a sustainable model that's extraterrestrially tested
SpaceX claims to be able to do it in as little as 90 days. You can go a lot faster with more free fuel. We've kept someone in space for 4 times that.
> Mars has more problems than a moon base, not significantly less
What are you referring to? Mars has available gasses, water, and more easily accessible useful solids than the moon. It will be easier to get radiation shielding on Mars, as the surface is more amenable to building underground structures.
> Except that we have no demonstrable way to do it
You are aware that we have sent probes to Mars, yes? The only difference between that and the human is how much money you're willing to spend to increase the chances of the journey being survivable.
What about the tech to grow food in space? Is it "just expensive" or it doesn't exists? I think it doesn't exist.
I think we need a dedicated food-growing space lab, and run it for least 10 years, until we're confident we have a robust technology that works.
Once on Mars, we could probably use something like this:
https://uanews.arizona.edu/story/the-martian-food-growing-sy...
For producing crops and oxygen, and maybe even supplies for a return trip.
Obviously it's not completely trivial to sustain humans on Mars, but there is literally no reason to believe we couldn't accomplish it using current levels of technology, to say nothing about whatever we're going to invent over the next fifty years.
Keeping humans alive on Mars starting from now is vastly easier to comprehend than putting a man on the moon starting from 1950. I wonder how many armchair pessimists there were for the space program back then.