It was forty years today (at 22:54:37 UT) that human beings left the moon for the last time. Commander Gene Cernan's last words as stood on the moon were lofty, rehearsed and memorized: "As I take man's last step from the surface, back home for some time to come (but we believe not too long into the future), I'd like to just say what I believe history will record: That America's challenge of today has forged man's destiny of tomorrow.