Through his correspondence with NASA, Feist learned of a bounty of newly available mission audio that no filmmaker had worked with. During the Apollo era, the agency had two 30-track tape recorders running concurrently in Houston that captured not only the flight director’s commands to his subordinates, but also all the so-called back-room loops, the channels through which NASA’s various headset-wearing controllers and support teams communicated with one another.

It was like a family discovering a forgotten shoebox full of old movies of major life events—only the family was America.

“If you picture the people sitting in Mission Control, each one is sitting at a different station,” Feist told me. “And if you want to hear what the flight dynamics officer was talking about with the guidance officer at a certain moment, you just turn on those two channels, and you can hear what those guys were saying.”

Until recently, it was nigh on impossible to hear what any of these guys were saying, because the antique, analog 30-track recordings had been neither digitized nor separated into their component tracks. But in a timely stroke of good fortune for Miller, a team of sound engineers at the University of Texas at Dallas recently completed a multi-year, labor-intensive program to transform these tapes—which include upwards of 10,000 hours of audio for Apollo 11 alone, spread over 60 channels—into digital files.

Slater clued in Miller to the files, and Feist wrote software to improve their fidelity. reducing the recordings’ flutter and wow, audio terms for the speed and pitch variations that arise from tape and recording irregularities. “You could still tell what the controllers are saying,” Feist said of the pre-cleanup audio, “but they all sound worried, like their voices are wavering. And nobody was worried.”

For Miller and Petersen, this cleaned-up 30-track audio was another means with which to tell the story of the mission in the present tense. One of its most fraught moments, familiar to space nerds but not to the general public, occurred just seven and a half minutes before the scheduled touchdown on the moon, causing fleeting but legitimate concern that the mission would have to be aborted. An alarm reading “1202” went off on the guidance computer of the lunar module, Eagle—not once but several times, and was soon joined by a second alarm reading “1201.” Neither Armstrong nor Aldrin was familiar with these codes.

This set off a scramble at Mission Control in Houston to figure out what was going on. Fortunately, a 24-year-old flight-software specialist who worked in one of the back rooms, Jack Garman, quickly determined what was happening—an “executive overflow,” or data overload, that was not mission-threatening. His reassurance was relayed up the chain of command and into outer space, in time for Eagle to land.

This episode is glancingly depicted in First Man. But thanks to the 30-track audio, the 1202 program-alarm story can be heard in Apollo 11 in its full vérité unfolding—you actually hear the kid savior, Garman, telling his guidance officer, Steve Bales, that if the alarm doesn’t reoccur, Eagle should be go for landing.

The Apollo 11 controllers didn’t just speak to each other about matters pertaining to the mission, either; in the movie, the audio finds them talking about their personal lives, and what was going on in the world. Petersen’s ears perked up when he heard a controller report for a graveyard shift early on July 20, having just come from a diner. “He’s on the loop,” Petersen said, “and he says, ‘Did you guys hear about Ted Kennedy?’”

The Chappaquiddick incident, in which Kennedy drove his car off a bridge near Martha’s Vineyard and fled the scene of the accident, leaving his passenger, Mary Jo Kopechne, to die in the submerged vehicle, had occurred just two days before—and temporarily knocked Apollo 11 off of the front page. It’s a useful reminder of the fraught context in which the mission took place—with the Vietnam War ongoing, the assassinations of Martin Luther King, Jr., and Robert F. Kennedy still in recent memory, and the Rev. Ralph Abernathy, the civil-rights leader and King’s successor as the president of the Southern Christian Leadership Conference, leading a protest at Cape Canaveral on the eve of the rocket launch, critiquing the “distorted sense of national priorities” that saw the federal government underwriting a trip to the moon while not doing enough to help America’s earthbound poor.