In the winter of 1962, the nation needed a hero.

Americans had yet to recover from the Soviet Union’s launching of the first spacecraft, Sputnik, in October 1957 — a rude jolt to our confidence as world leaders in all things technological. The space race was on.

Soon after he took office in 1961, President John F. Kennedy had thrown down the challenge to send men to the Moon by the end of the decade. But the Russians still set the pace, boastfully. They launched a dog into orbit, then the first man, Yuri A. Gagarin, and another, Gherman S. Titov.

The United States lagged, managing only two 15-minute suborbital astronaut flights — only five minutes of weightlessness each time.

Then, on Feb. 20, 1962 — 50 years ago next Monday — a Marine Corps fighter pilot from small-town America stepped forward in response to the country’s need. The astronaut was John Glenn, whom the author Tom Wolfe has called “the last true national hero America has ever had.”...