For Mr. Armstrong, Mr. Aldrin and Mr. Collins, their experiences back on earth reflected their differing characters. Post-Apollo, Mr. Armstrong resigned from NASA and quietly took on a teaching job at the University of Cincinnati. He died in 2012. Mr. Collins became director of the Smithsonian’s Air and Space Museum.

Today, at 88, Mr. Collins says he doesn’t think a lot about Apollo 11 — “I can’t say I wake up every morning thinking, Oh, Apollo 11, blah blah. I may, in normal times, go a month or two without thinking about it. But when I do, it comes back with a great deal of clarity, more than I would have guessed.”

Of the three, Mr. Aldrin, now 89, seems to have had the hardest re-entry. He drank. He had affairs, and got divorced, and remarried, and divorced again. He wound up in the hospital, crushed by depression.

At one celebratory banquet, Mr. Aldrin was breathlessly asked, “Tell us how it really felt to be on the moon!”

Afterward, he rushed outside into an alley and wept.

It’s a heartbreaking story, but it’s hard not to recognize something familiar in this moment. Only 12 Earthlings have known the exhilaration of standing on the moon. But most of us know what it is like to feel despair, to wonder whether we are up to the challenges that our lives demand.

It’s not just Buzz. It’s all of us.

Mr. Aldrin is a hero not only for his work as the lunar module pilot, but for his work in destigmatizing depression. One night, while he was hospitalized, he looked up at the full moon. “What I said to myself was simple enough. ‘You’ve been to the moon. You did it,’” he recalled. “‘Now get the hell out of here and live the kind of life you want.’”

I’ve never stood on the moon, but I have had a couple of life-altering experiences, and I’ve wondered, now and again, how to live my life in their wake. In June 1988 I watched my bride walk down the aisle of the Bethlehem Chapel at the National Cathedral, wearing her mother’s wedding dress. “Jesu Joy of Man’s Desiring” played upon the pipe organ. At that moment I felt myself transformed by love, lifted out of the life I had been living and into a new world.