"Returning to the moon is an important step for our space program," declared President Bush in January 2005, announcing his intention to "give NASA a new focus and vision for exploration" by putting Americans back on the moon by 2020, followed by the first manned mission to Mars. Months later, NASA's incoming administrator, Michael Griffin, vowed that despite the staggering cost of this bold vision — conservatively estimated at over $100 billion — not "one thin dime" would come out of his agency's budget for unmanned space science.