I listened to the interview he did on NPR three years ago.
"Adventure found me, and found me often."
My great-grandfather tried doing the lying-about-his-age thing to get into WWI, also, he wanted to be a fighter pilot - but he was only 14 at the time, so fat chance of that happening. Ended up rafting up and down upstate New York instead for a year or two.
Happiness is zero-gee with a sinus cold.