Homer Hickam is the author of “Rocket Boys” and “Carrying Albert Home.”

We’ve lost the last of the Mercury Seven astronauts, the prodigious test pilots chosen to be the first Americans to fly into space. In the 1960s, nearly every American youth could list them: Shepard, Grissom, Glenn, Carpenter, Schirra, Cooper and Slayton. Only Gus Grissom would die with his spacesuit on (during the Apollo program), but all were heroically willing to go into the unknown — not for themselves, not for scientific purposes, but for us, the American people, made fearful by a strutting Soviet Union not only armed to the teeth with nuclear weapons but also clearly intent on carrying its hammer-and-sickle philosophy to the moon and beyond. It was a scary time for Americans, but the Mercury men, with their swagger and big grins, projected a confidence that we could share. We reveled in their boldness, not to mention (especially for us boys) their fondness for gorgeous women, hot cars and speed.

Ironically, John Glenn, the Mercury astronaut most Americans can still name, was the quiet one. He was strong and steady and never in any manner outlandish. He touched us in a different way. There was something about that balding, red-headed Marine with his lopsided smile that just made people love him. It seemed to those of us following the space race back then that everything Glenn did, his Midwestern, “aw shucks” manner of speech, his obvious love for and dedication to his wife, Annie, even his daily jogs along the Cape Canaveral beach, was pure and wholesomely American. The Kennedy administration instantly picked up on his popularity and made him and Annie regulars at the White House and Hyannis Port, where Jack and Jackie treated them like old friends.

John Glenn poses for a photo with the Mercury "Friendship 7" spacecraft. (NASA/Reuters)

Once, in 2004, while I was on a book tour in Ohio, a mutual friend in Columbus organized a dinner for me and the Glenns. I was placed across from Glenn and found him to be cordial and courtly, but somewhat shy. He warmed up a little when we shared tales of our boyhood, his in Ohio, mine next door in West Virginia. I had chanced upon and spoken to Kennedy when he was running in the 1960 West Virginia presidential primary, but when I told Glenn about the encounter, he winced. He fumbled a response, but I could tell he really didn’t want to talk about President Kennedy, and so I changed the subject. Decades later, it seemed, the assassination of the young, charismatic president who was also his friend still caused him some discomfort and pain.

Glenn’s 1962 Mercury flight was fraught with dramatics, from his “Zero G and I feel fine!” exultation upon entering orbit to his reentry with what was feared was a faulty heat shield. After he safely splashed down, the nation erupted with applause and gratitude not seen since Charles Lindbergh’s solo flight across the Atlantic. Swept into the Kennedy lifestyle, and all but made a member of the family, he was left dangling when JFK was killed and Lyndon Johnson, no friend of Kennedy friends, took over. His astronaut career over, it was only a few months after the assassination that Glenn announced a run for the Senate, apparently honoring a promise to help keep alive the New Frontier. He failed twice but kept trying, and finally made it in 1974.

But by then, the Kennedy optimism had been swept aside by Vietnam and Watergate, and Glenn the politician was unable to awaken within himself the passion and dedication he had shown as an astronaut, or to connect anew with the American people. His reputation suffered terribly in the Keating Savings and Loan scandal, when, although cleared of lawbreaking, he was reprimanded by the Senate for “poor judgment.” During those decades, he seemed a stranger in a strange land, a colorless man important only as a reliable vote for the Democrats in Congress.

Mark Twain famously said that God looks after fools, drunks and the United States of America. Add to that somewhat tongue-in-cheek maxim a certain American hero named John Glenn. Trudging along for years as a dispassionate politician, he caught fire again when he got it into his head to fly aboard the Space Shuttle in 1998. By all accounts, once he secured a seat, he gloried in every second of the training and his days in space. It is my hope that during that time, the optimism of the New Frontier returned to Glenn’s life. For the spirit he gave a beleaguered nation so long ago, it was the least we Americans could do for him.