"That's one small step for man, one giant leap for mankind!" The famous words spoken by Neil Armstrong in 1969, created one of the most unforgettable moments in U.S. history. Even before that first-ever landing on the moon, astronauts began navigating their way through the thrill and mystery that is outer space. From John Glenn, the first American astronaut to orbit the earth, to Sally Ride, the first American woman to enter space, these famous names have taken space exploration to new heights.