Take Mars.
First, I don’t have any particular itch to go to, or send people to Mars. I think it can wait. I also see the potential to repeat the error of Apollo if we follow Dr. Thronson’s advice:
A useful tautology: humanity’s second—or third or fourth—mission to Mars will never happen unless there is a first one. Vastly more resources have been expended on concept design and technologies that appear to be necessary for sustained Martian exploration, with comparatively fewer specifically on the most essential mission, the first one. Just as with all programs of human exploration, the first Mars expedition will be very—very!—different from every one that follows. It will have to be more limited, more focused, and necessarily affordable from the start. More will be learned on a first mission, no matter how limited it is some respects, than on any subsequent one. However, in the current, uncritical, and comfortable environment for proliferating concepts for human exploration beyond LEO, there seems to be only modest interest in the difficult process of in-depth, critically reviewed engineering designs for the first Mars mission.
I disagree that “all programs of human exploration” had a first mission that was “very-very! different” from those that followed. The Vikings did nothing different on their succeeding journeys than they did on their previous ones. Neither did the Polynesians. There was little difference between Columbus’s first voyage, and his subsequent ones, or those of others. They all used the same basic technology. There were no significant differences until the technology evolved — more efficient sails, canned food, ship-board clocks for navigation, steel hulls, steam engines. Similarly, most exploration of the North American continent were very similar, from the initial ones by the early French explorers to Lewis and Clark, through Walker and Fremont. Not until the development of first the Conestoga, and then the railroad was there any significant improvement. In fact, as I write in the book:
Once Columbus showed the way, fortune seekers and settlers didn’t wait for shipboard clocks, or steam engines, or steel hulls. They set sail for the New World with what they had. A century or so ago, Rosemary and Stephen Vincent Benét wrote a poem about the days of sail, whose first stanza was:
There was a time before our time,
It will not come again,
When the best ships still were wooden ships
But the men were iron men.
Even with Apollo, the subsequent missions weren’t that different from the first, in terms of how they were carried out, except they got better at navigation and precision in landing sites, and took more equipment, such as rovers, to expand the science. So I don’t accept his premise that the first Mars landing will be significantly different than the second one. But the next series of lunar missions will doubtless be much different from Apollo, because Apollo was done in an economically unsustainable way, because there was a national imperative to do it. We have to avoid that with Mars.
I also think that there are some elements of straw man here. No, we don’t need to go to the moon to get to Mars. But we do need to develop some infrastructure if we are going to do it in anything resembling an affordable way, and no, a government-developed heavy lifter is not part of that infrastructure. But I don’t see any societal will to compel the government to do a manned Mars mission in the foreseeable future. If it happens, it will happen privately.