I think your example actually harms your argument. The SR-71 is a nice plane, and certainly much more advanced than the Wright Flyer, but it is completely outcl

I think your example actually harms your argument. The SR-71 is a nice plane, and certainly much more advanced than the Wright Flyer, but it is completely outclassed by the Saturn V. The space technology is much more complex, and much more energetic, and has far tighter tolerances, and less room for failure. You should have been making this same argument in the early sixties. Right now we do have the technology, the engines, the fuel, the deep-space communications network. We need to scale up the engines to rival the power of God Almighty, but we don't need new physics to do so. Musk is pointing out, correctly, that this is possible with existing rocket technology -- at least the transportation. Keeping people alive once they're there is apparently somebody else's problem, but until we have the materials science for a space elevator, an obscenely heavy lift vehicle will probably have to do. Ultimately he's going to be asking a lot of people to climb on top of a monstrous Engine and hope that it explodes correctly, and I hope that his conscience is clear when that day dawns. Probably you are right that we're going to have a hell of a time keeping people alive on Mars, but we seem to have a tough time of that here as well. This is not science fiction. There is no new physics required, just some fiendishly difficult engineering challenges. The Wright Brothers were able to build their plane because there was nothing physically stopping them. They had the scientific knowledge and the dedication, and everything else followed. Really it's not that people -- even Presidents -- haven't been talking about doing this and working on details and preliminaries for decades. This is news precisely because it's not science fiction. This time, it could actually happen.