On July 20, 1969, astronauts Neil Armstrong and Buzz Aldrin touched down in the lunar module Eagle, becoming the first humans to walk on the moon. Nearly 50 years later, Apollo 11, a documentary by Todd Douglas Miller that included raw footage from the days leading up to the mission, the landing and return—much of which had not been seen by the public—premiered at the 2019 Sundance Film Festival. The film was released in IMAX theaters in March, and will be broadcast on CNN on June 23 at 9 P.M. EST.

Bill Barry, NASA’s chief historian, worked with filmmakers and historians at the National Archives to assist with the making of the film. Scientific American spoke with Barry about the process and the mission’s legacy.

[An edited transcript of the interview follows.]

How did the documentary come together?

We heard from Todd Miller about his interest in doing the movie. And we worked with Dan Rooney at the National Archives, who pointed out to Todd that they had all this wide-format footage of the Apollo mission, but didn’t have the equipment to screen it. Dan and Todd built this partnership where the National Archives got that stuff digitized and Todd got exclusive rights to use them for the movie. So, everybody benefited from that partnership.

Bill Barry, NASA Chief Historian. Credit: Paul Morigi Getty Images

What’s your favorite part of the film?

The crowd scenes at the launch are pretty amazing. And the decision not to narrate the movie was brilliant. I was really moved by the footage of Neil and Buzz and Mike getting suited up in the crew quarters. I’ve been in that room, and to see footage was just eye-watering to me. It was pretty amazing.

When did you first become interested in space?

Literally the first thing I can remember is sitting in front of our little black-and-white TV on the linoleum floor of our living room, watching Walter Cronkite ask, “Will John Glenn get back safely from orbit?” [This was during America’s first attempt at an orbital spaceflight in 1962.] It made a really vivid impact on me. And after that, I was hooked. I wanted to be a part of that whole thing. When I was a kid, I wrote a letter to NASA about once a month, and I’d get a package of stuff in return, pictures and lithographs of spacecraft and astronauts.

What is it like to be NASA’s chief historian?

It’s a great job because NASA is something I love, but it’s also very popular—it’s an easy sell for me to go talk to a group of people about NASA history. People have lots of questions and know the history pretty well. But like any active government agency historian, sometimes it feels like, “Stop making history—I’m too busy!” Every day, we make some new history here. And that’s exciting.

What was the historical context of the Apollo missions?

At NASA, everybody was completely focused on getting to the moon, and it was a tough assignment. People basically just worked at NASA continuously; they would sleep on cots in the office, particularly during missions. I think people saw it as a national mission, that the country was depending on them to make it happen.

On the outside, the 1960s were a period of huge turmoil. The postwar generation was starting to come of age, and people were questioning what the values and priorities of the government were. They were asking, why are we spending so much money on space? And why are we sending our young people off to die in Vietnam? And the civil rights movement was happening, and gender equality was coming to the forefront. The country was in the process of changing, and the birth pangs of our current life were happening. And in the middle of all of that, there’s a bunch of engineers at NASA trying to get us to the moon and back safely.

What was the most important technological advance that helped win the space race?

One of the things that hadn’t been solved yet at the time was how to make cryogenic engines that could run on liquid hydrogen and liquid oxygen. Sorting out that technology was critical, and the Russians never did figure it out during the sixties. And computing power was really important. It took a huge amount of effort to get the Apollo guidance and navigation computer to work, because they were basically building a breadbox-sized computer when your typical computer was the size of a large room.

What lessons can we draw from the Apollo program to apply to challenges we face now, such as climate change?

One of the big triumphs of the Apollo program was that we managed to make it all come together and work. Going to the moon in less than 10 years seemed pretty impossible to a lot of people at the time, but we managed to make it happen. To a great extent, I think the lesson that comes out of Apollo is how to manage a big project and that big projects can be done.