An anonymous reader writes: On July 20, 1969, U.S. astronauts Neil Armstrong and Buzz Aldrin became the first humans to walk on the moon. Neil Armstrong would say later he thought the crew had a 90% chance of getting home from the moon, and only a 50% chance of landing safely. The scope of NASA's Apollo program seems staggering today. President Kennedy announced his moon goal just four years into the Space Age, but the United States had not even launched a human into orbit yet. Amazingly, just eight years later, Armstrong and Aldrin were walking on the moon.