When John Glenn entered the Oval Office on February 5, 1962, he found a president in need of assurance. In a matter of weeks, Glenn would attempt to become the first American in orbit. John F. Kennedy wanted to know whether Glenn’s spacecraft, Friendship 7, was safe to fly.

For the astronaut, of course, this was a life-or-death question. For Kennedy, the stakes were well short of that but still exceedingly high. Almost a year had passed since a Russian cosmonaut, Yuri Gagarin, had become the first person in space, circling the Earth once and returning safely. If Glenn’s mission failed, it would not only be a tragedy; it would be a national humiliation, signaling that America was fated to remain second in space—that it could not compete in this new arena of the Cold War.

John F. Kennedy inspects the Mercury space capsule on February 23, 1962, following Glenn’s return to Earth. Glenn is to the right.

Glenn told Kennedy that NASA had done everything in its power to protect its astronauts. If so—and this was doubtful—it might not be enough. By the time of Glenn’s visit to the White House, his flight had been postponed six times, most recently due to “technical difficulties with the launch vehicle,” as NASA put it. Before that, it was the space suit: the seal rings on Glenn’s gloves had leaked oxygen. Before that, the fuel tanks were at fault.

As the delays continued, as weeks became months, news coverage took a darker turn. “Many things could go wrong,” The New York Times pointed out, listing, for reference, some of the many malfunctions that “could mean death for the red-haired test pilot” from New Concord, Ohio. At a press conference, a reporter asked NASA spokesman Shorty Powers whether Glenn would take “a cyanide capsule or anything like that” if he got stuck in orbit. “No,” Powers said grimly, “nothing like that.”

A Fine Line

In public—as in the Oval Office—Glenn appeared confident, calm, utterly unworried. “I feel fine,” he told the press after his 10th postponement, adding that every delay had an upside: it gave him more time to train.

Glenn in orbit. The launch was delayed 10 times before finally taking place on February 20.

But this was a front. The long wait was wearing on the 40-year-old astronaut. Glenn was about to be shot into the vacuum of space and already felt isolated, imperiled. Behind the scenes, he feuded with flight directors, who saw astronauts as backups to the autopilot system and resented his refusal to fall in line. “Never felt so alone,” he complained in notes before a meeting about his flight plan—notes later discovered in his archives at Ohio State University. “So many against. Why?”

Glenn was also confronting his own mortality. On the eve of his flight, alone in crew quarters at Cape Canaveral, he dictated two recordings into a handheld microphone: one to his wife, Annie; the other to his teenage children, Lyn and Dave. The reel-to-reel tapes were to be played if he didn’t make it back alive.

Glenn (second from left) and Soviet cosmonaut Gherman Titov (second from right), following Glenn’s space flight.

The script for Glenn’s message to his kids, which he wrote by hand on a legal pad, began on a blunt, arresting note: “If you hear this, I’ve been killed.” He assured them that he’d “made peace with God a long time ago before this happened.... Always believed life continuing after [death] & it does. I can tell you that.... I know what it’s like now.”

Glenn coached Lyn and Dave on how to get through his funeral—a ceremony at Arlington National Cemetery in which there might be no body to bury. “The father … you knew and know is not in that body, even if you get it back, remember I’m not in it,” he said. “No need to fuss over something like that, is there? Little like fussing over an engine when all fuel has evaporated from [the] tank.”

Kennedy receives a gift of the American flag Glenn carried in his space suit during his flight aboard Friendship 7.

But, above all, Glenn wanted his children to feel that he had not died in vain. “That’s how progress is made—little contributions from many,” he said. “Mine was maybe a little more spectacular but was certainly not as much of a contribution to progress as many people make in their fields each day.... So be glad, as I am, that my life was not wasted.”

On February 20, 1962—15 days after his White House meeting with Kennedy—Glenn was strapped into his capsule and waited, atop a rocket, for liftoff. By radio link, he spoke to Annie. He was exuberant now—“keyed up,” in his phrase. But before he signed off, before he said good-bye, he asked Annie a question: Had she received the recordings he’d made? She said she had.

Jeff Shesol’s Mercury Rising: John Glenn, John Kennedy, and the New Battleground of the Cold War is out now from W. W. Norton