William A. Anders, the astronaut behind perhaps the single most iconic photo of our planet, has died at the age of 90.

On Friday morning, Anders was piloting a small plane that dove into the water near Roche Harbor, Wash. His son Greg confirmed his death.

Anders retired from the Air Force Reserve as a major general, but was a major at the time of the Apollo 8 mission in 1968. Apollo 8 was the first manned mission to orbit the moon, which also made Anders one of the first people to leave the bounds of Earth’s orbit.

On Christmas Eve, all three Apollo crewmembers took photos of Earth as it rose over the moon’s horizon, but Anders was the only one shooting on color film. The ship’s onboard tape recorder captured the astronaut exclaiming, “Oh my God, look at that picture over there! There’s the Earth comin’ up. Wow, is that pretty!”

The resulting photograph, titled “Earthrise,” captured Earth’s loneliness and fragility in a way that no image ever had before. It was particularly iconic to the nascent environmental movement — fifty years later, Earth Day Network President Kathleen Rogers wrote that photo “confirmed” the movement’s conviction “that the Earth’s environment was common to all of us, that the Earth’s natural resources were finite, and that 150 years of unfettered industrial development was having a profound impact on our planet.”

In an interview conducted in 2015, Anders noted that his photo seemed better-remembered than the Apollo 8 mission itself.

“Here we came all the way to the moon to discover Earth,” he said.