Wally Schirra

In the 1950s and early '60s, a small band of high-altitude pioneers exposed themselves to the extreme forces of the space age long before NASA's acclaimed Mercury 7 would make headlines. Though largely forgotten today, balloonists were the first to venture into the frozen near-vacuum on the edge of our world, exploring the very limits of human physiology and human ingenuity in this lethal realm.

A testament to NASA's Apollo program of the 1960s and '70s. Composed of actual NASA footage of the missions and astronaut interviews, the documentary offers the viewpoint of the individuals who braved the remarkable journey to the moon and back.

National Geographic's riveting effort recounts all 12 crewed missions using only archival footage, photos and audio.