At the 2016 International Astronautical Congress, Elon Musk made a presentation, "Making humanity a multiplanetary species (http://www.spacex.com/mars)." In it, he outlined a wildly ambitious plan to put 1 million people on Mars within 100 years.
What made this presentation different from previous pronouncements by Presidents and advocates alike is that Musk isn't calling on someone else to do it. He's planning to do it, and he has a plan to get the resources. He's built a multibillion dollar enterprise with the express purpose of creating the necessary infrastructure. And, as a privately-held company, SpaceX is able to do something no publicly-traded corporation can: it can reinvest its profits wherever necessary, for as long as necessary. It can make whatever technology bets it finds useful, and it need fear failure only to the extent that affects customer confidence. If Musk succeeds, it won't be because he's the only one who can. It will happen because he's one of the few who has both the desire and the resources.
Following the IAC presentation, Musk and SpaceX went largely silent on Mars plans. There was a Reddit AMA, a National Geographic "Mars" mini-series, and a somewhat-mysterious pressure test of the carbon-fiber tank Musk revealed at the end of his IAC presentation. But details on the the transport system, the Mars Colonial Transport for travel to Mars and back, weren't forthcoming. The plan to send a Red Dragon to Mars in 2018 slipped to 2020, and now Red Dragon seems cancelled altogether, as its Dragon 2 predecessor undergoes changes in preparation for manned flight.
Musk himself has offered some tantalizing tweets, suggesting that the MCT/Interplanetary Transport System may have been a bigger bite than SpaceX could chew--certainly it faced a chicken-and-egg situation with regards to manned missions to Mars, to say nothing of the enormous development costs. Next week promises some answers, as the 2017 IAC kicks off.
Regardless, it remains clear that SpaceX is continuing undeterred. The first flight of Falcon Heavy is scheduled for later this year, a possible Apollo 8 reprise is in the cards, and with or without landing legs, Dragon 2 development continues. Perhaps most importantly for his Mars ambitions, Musk has indicated he's "figured out how to pay for it." Mostly likely, that means he's figured out how to make it pay, potentially opening up additional requirements for engineering solutions.
In addition to all the technical things we'll need for Mars, the people who go will need to figure out a lot of non-technical stuff, too. What law will apply on Mars? What social safety net will exist? What limits will Earth impose on colonists? What happens to a colonist if he or she commits a crime, becomes depressed and unable to work, or refuses to abide by some Earth-directed rule (say, planetary protection)? All good questions, but not the focus here.
The focus here is on all the technical things that "those future people" will need to figure out. Because, in one stroke, Musk made "those future people" into us. We may not actually get there; the Mars Colonial Transport may never be built. But we might; it might. And if we do, that means that the engineers who will need to figure this out won't be born in a hundred years, or even fifty. They're us. And if we don't figure those things out, the Mars Colonial Transport won't have any place to go.
So, let's assume MCT or something like it happens, even if it takes longer than SpaceX would like. Then, bit by bit, I'd like to explore what needs to be built, what the mission design parameters might be, what order things need to happen, and so on. Sure, others have worked on this--Zubrin and Aldrin come to mind; both have sketched out detailed architectures for getting to and exploring Mars. But, they didn't have the MCT or its smaller sibling as a forcing function, and a company and a billionaire focused on making it happen now, not when a group of governments decides to. That's new, and MCT makes every previous plan OBE.
With a little luck, others will join the discussion and move it along more quickly.
Oh, one other note as we start--I don't know Elon Musk. I can't bring myself to call him "Elon" when I've never met the man. Maybe, if this takes off, some of the SpaceX engineers will join in, and recommend he drop by.