If We Want to Send Astronauts to Mars, We Must Go Back to the Moon First, Scientific American
"Bush's idea was inspiring enough that, in addition to NASA, no fewer than 13 international space agencies signed on to participate in developing a plan for reaching the moon. Unfortunately, the plan's implementation was badly flawed. NASA tried to relive the glory days of Apollo by focusing on one-use vehicles that would transport everything to the moon from Earth. Apollo was a fantastic achievement, but it was not sustainable, which was in part why the program was canceled in the early 1970s. Bush's vision proved too expensive to sustain as well, and in 2010 President Barack Obama declared that the U.S. had no need to go back to the moon, saying, in essence, that we've been there, done that. Instead, he said, we would go to Mars without taking that interim step. But a return to the moon is crucial to the future of human space explorationand - not just for the experience it would give us in off-world living."