Smithsonian.com

On July 16, 1969, NASA launched Apollo 11, the mission that put two men on the moon four days after lift-off.

Forty years later, historians and NASA officials are still trying to gauge the legacy of the Apollo program. On Thursday, five panelists met at NASA headquarters to discuss its impact.

Many of their conclusions were expected: Apollo was one of, if not the, greatest achievement of the 20th century, a claim that all five participants repeated throughout the hour. Humans will remember this moment not only for arriving at the moon, but also for leaving this planet. Photos from Apollo of Earth showed a fragile orb surrounded by the darkness of space and gave a boost to the environmental movement, said Roger Launius, curator at the National Air and Space Museum, as he noted Earth Day was first celebrated in 1970.

Craig Nelson, author of Rocket Men: The Epic Story of the first Men on the Moon, observed that before Apollo, space travel was science fiction—and now it’s a form of transportation. The geopolitical context of the Cold War was the driving force behind the Apollo mission and President Kennedy’s support of the program, as John Logsdon of the Air and Space Museum reminded us.

But there were some unexpected critiques of the program, too. Apollo had one goal, which was to reach the moon before the Soviets. President Kennedy gave a timetable of accomplishing that goal by the end of the 1960s. While this was good for mobilizing public support, it created a precedent that makes it hard for multi-goal programs today, like Constellation, to gather similar support (Constellation has eight main goals and a 20-year timeline for achieving them). This was something that all of the panelists agreed with, including Cristina Guidi, director of Constellation’s exploration systems mission directorate.

In addition to scholarly discourse, the Apollo anniversary is an opportunity for celebration and inspiration. You can follow the action on Twitter, watch archival footage of the first steps on the moon or chronicle the entire flight of Apollo 11 in realtime.