For the first time since 1972, the United States is planning to fly to the moon, but instead of a quick, Apollo-like visit, astronauts intend to build a permanent base and live there while they prepare what may be the most ambitious undertaking in history -- putting human beings on Mars. President Bush in 2004 announced to great fanfare plans to build a new spaceship, get back to the moon by 2020 and travel on to Mars after that. But, with NASA focused on designing a new spaceship and spending about 40 percent of its budget on the troubled space...