When President George W. Bush officially announced the new space initiative at NASA Headquarters on January 14, he invoked the memory of a famous pair of explorers, Lewis and Clark. As Bush put it: Two centuries ago, Meriwether Lewis and William Clark left St. Louis to explore the new lands acquired in the Louisiana Purchase. They made that journey in the spirit of discovery, to learn the potential of vast new territory, and to chart a way for others to follow. America has ventured forth into space for the same reasons. A closer reading of history, though, suggests that the...