Of all human spaceflight, Apollo 8 may have best demonstrated NASA’s capacity to change human perspective. In reflecting upon that mission, the first circumnavigation of the moon, the astronaut Bill Anders, one of three on board, said, “We came all this way to explore the moon, and the most important thing is that we discovered the Earth.” Anders had taken the photograph that came to be known as “Earthrise,” the first image of the planet captured by a human from beyond Earth’s orbit. As his fellow crew member Jim Lovell would point out, “Suddenly, everybody could see the Earth as it truly is: a grand oasis in the vastness of space.”

It may seem counterintuitive to think that space exploration, with all its attendant risk and glory, primarily sheds light on our own home planet. But it does. This week marks the 60th anniversary of NASA’s founding. For the past two years, we have been making a documentary about NASA, and that idea was pretty much echoed by all 45 of the astronauts, scientists, administrators and historians we interviewed.

Very early on, NASA uncovered two important truths. First, that our planet was the only one in our solar system with an environment capable of supporting human life and, therefore, extraordinarily unique. And second, that earth’s environment was fundamentally fragile, protected by a thin iridescent layer of atmosphere and susceptible to damage at the hands of the planet’s inhabitants.