Apollo 11 represented an incredible triumph of human ingenuity. Less than a decade after President Kennedy announced that we would send a man to the moon and return him safely to Earth, we had done exactly that.
Several Apollo missions followed, the last one taking place in 1972. President Nixon asked Vice President Agnew to head up a commission that would decide how the United States would build on the success of Apollo. Agnew's group recommended an aggressive move out into the solar system, including human landings on Mars. It made sense at the time, and seemed a natural next step, but the war in Vietnam, money problems, and the fall of both Nixon and Agnew for ethical violations scuttled these ambitious plans. Instead, Congress gave enough money only to begin the shuttle program.
These are the conscious reasons usually given for the retreat from the moon back to Earth orbit. However, I think there are other subconcious reasons why we stopped at the moon, and are only now beginning to plan a return.
I will discuss these reasons in my next post.