Most Americans recognize names like Neil Armstrong and Gene Cernan. But like the anchor beneath the surface that keeps the ship from drifting away, Armstrong and the other famous astronauts who made it to the moon owe their safe return to the men in the Mission Control room at the Johnson Space Center.

Rick Houston and Milt Heflin give the engineers on the ground their due in Go, Flight!: The Unsung Heroes of Mission Control, 1965–1992 (Nebraska, 2015). The men (and later women) who worked on the third floor of Building 30 were the brightest of their generations, making split-second decisions that determined the success or failure of a mission. The flight controllers, each supported by a staff of specialists, were the most visible part of the operation, running the missions, talking to the heavens, troubleshooting issues on board, and, ultimately, attempting to bring everyone safely back home. None of NASA’s storied accomplishments would have been possible without these people.

The book serves as the inspiration for the new documentary Mission Control: The Unsung Heroes of Apollo. Director David Fairhead highlights the emotional and psychological struggles that hung thick in the air of Mission Control—quite literally, as cigarette smoke often clouded the room. These men would not—could not—fail, and their incredible successes took their toll.

Catch a glimpse of Mission Control here—and don’t forget to read it before you see it!