It has been home to the U.S. human space flight program from the final Mercury flight to today's space shuttle and International Space Station missions.

An actual Apollo Saturn V launch vehicle which was originally built to take a crew of astronauts to the Moon has been on permanent exhibit since 1978 in the Johnson Space Center’s Rocket Park. In the background are Mercury-Redstone and Little Joe rockets.

In September 2001, NASA's Johnson Space Center celebrated 40 years of leading America into space. The history of the center is the history of America's human space flight program. Both illustrate the determination and the vision of people to rise to unexpected challenges and to work together to attain success.

Here's a look at what has happened over the past 40 years and what the coming 40 years portend.