“Urban myth,” Wikipedia tells us, “is a form of modern folklore consisting of stories thought to be factual by those circulating them.” More often than not, any kernel of truth at the core of the stories is somewhat exaggerated in their modern retelling. As we recede from the 40th anniversary of the first steps taken by humans on another world, it has become clear that the intervening time has allowed for many myths to arise in the exploration folklore. And those myths have now led us down a dead-end, almost certainly unsustainable, path back to where we started.