The ultimate strangers in a strange land, travel-weary astronauts Gene Cernan and Harrison "Jack" Schmitt huddled in their tiny Apollo 17 lunar lander, ate military-issue omelets, harmonized "good morning to you" and stumbled through a silly parody of The Night Before Christmas. The date was Dec. 14, 1972, the day America retreated from the moon. Apollo 17, launched 30 years ago Saturday, represents the closing chapter in an awe-inspiring series of a half-dozen, 240,000-mile expeditions that unfolded over a dizzying 42 months. The Apollo program delivered a dozen American astronauts to the moon's rugged terrain for an unprecedented, firsthand look...