Widely recognized and lamented, the start-stop churn in NASA human space exploration results in waste in both fiscal and human terms. How can this churn be minimized? How can human space exploration be made to stay the course, be made sustainable across administrations, across budget crises, across generations — across setbacks and accomplishments? Not to suffer the same fate as Apollo, how do we continue human exploration of Mars after the first several landings? And how do we defeat the “been there, done that” platitude that can rob exploration of its richness?