Neil Armstrong’s passing reminded me of the moment I learned of his historic accomplishment. I didn’t gather with my family around the television to watch him take his “small step” onto the surface of the moon. When the momentous event occurred, I had no idea it was happening. I and several hundred comrades were otherwise engaged — prisoners of war in the enemy’s capital, where in 1969, news could travel slowly.

Our captors in Hanoi went to considerable lengths to keep us in the dark. They didn’t restrict our access to all news but were selective about the information they allowed to reach us. They routinely apprised us of anti-war protests, race riots, assassinations and the like. Reports were usually piped into our cells during Hanoi Hannah’s “Voice of Vietnam,” an often unintentionally funny, if repetitious, daily broadcast about America’s manifold sins and woes.

“American GIs, don’t fight in this illegal and immoral war,” Hannah would plead, while cheerfully regaling us with victories by the people’s liberation forces and the latest evidence that the United States had become a dystopian society.

Like much of the treatment we received in prison, propaganda was intended to discourage us and weaken our will to resist. By portraying America as so beset by turmoil that it had become a different country than we remembered, a country that had forgotten us, our captors hoped to convince us that whether we remained imprisoned or went home, whether we lived or died, were entirely their decisions.

It rarely succeeded, but our morale, if not our will to resist, suffered under our steady diet of grim news. Every morsel of good news we managed to obtain brought immense pleasure. Although we didn’t wish for more Americans to be captured, neither did we want to waste a moment before learning what they knew. Newly captured prisoners were probably perplexed to be insistently pressed for uncensored information about the war and home as they struggled to come to grips with their new circumstances. Prison is hell on good manners.

Once in a while, the Vietnamese unwittingly let a little good news slip by. One evening, Hannah played a clip of a speech by a prominent American opponent of the war. It was a quick, throwaway line in a long list of diatribes about the war and the president. But we all caught it. The quote was something like: “President Nixon can put a man on the moon, but he can’t end the war in Vietnam.”

Yes, that was news to us, arriving years after the successful Apollo 11 mission.

We had all heard President John F. Kennedy commit our country to putting a man on the moon within a decade. Most of us prisoners were pilots, and we admired and envied the pilots who became Mercury, Gemini and Apollo astronauts. Most of all, we wanted our pride in our country, our love for the place where free people reached for the stars, reaffirmed in the place where it had been tested and mocked.

In that one screw-up, that brief mention of glorious news, our morale soared. We felt almost physically strengthened as we communicated with each other in whispers and tap code: “Did you hear that? Did you? We put a man on the moon. My God, we did it.”

Many years later, I had the honor of meeting the man who planted that flag. I told him how we had learned what he had done and how much it had meant to us. Armstrong was a brave man who made his countrymen proud, but he was also a modest man with a quiet demeanor, and he seemed moved by the recollection.

I could never pay adequate tribute to how much he had once inspired me, in a place that at times seemed almost as distant from America as the moon.

Rest in peace, Neil Armstrong, and thank you from the bottom of my heart.

John McCain, a Republican senator from Arizona, was the party’s presidential candidate in 2008. He was a U.S. Navy pilot who was captured in Vietnam in 1967 and held until 1973. He wrote this for The Washington Post.