The former chief historian of NASA explains why we haven't gone back to the moon since the Apollo program ended, despite many presidential promises.

Saturday, July 20, is Moon Day and the 55th anniversary of the first Apollo 11 moonwalk. Here’s a look at the Apollo program and the new Artemis program to return to the lunar surface.

Richard Jurek, a marketing and public relations executive, is the co-author of "Marketing the Moon: The Selling of the Apollo Lunar Program". He wrote this for Zocalo Public Square.

Some of these movies take a broader sweep of outer space, while others zoom in on pivotal moments in NASAs Apollo Space Program.