@jan The second vowel in "Amman" is /ɑ/, not /æ/.

As usual with these things, that depends on your dialect. In Irish English, 'Amman' and 'a man' are indeed homophones, with the second vowel realised as [a:] (in my case anyway). I think the same would be true of some English dialects.

Note also the perhaps different semantics of anarthrous "man" in the last words spoken while still on the lunar surface by the last individual man to have stood there to date (Eugene Cernan): "I'm on the surface; and, as I take man's last step from the surface, back home for some time to come — but we believe not too long into the future — I'd like to just [say] what I believe history will record. That America's challenge of today has forged man's destiny of tomorrow. And, as we leave the Moon at Taurus-Littrow, we leave as we came and, God willing, as we shall return: with peace and hope for all mankind. Godspeed the crew of Apollo 17." I expect that I was not alone in believing at the time that "not too long" could not possibly stretch out to as long as almost 40 years and counting. In terms of the genericity of "man" in the relevant variety of English at the relevant time, while NASA's astronauts as of that point had been exclusively male (although the Soviets had already had one female cosmonaut), by the time Apollo 17 reached the moon, we had already sent off into space the first of the "Pioneer plaques" depicting for the information of potential future extraerrestrial viewers both the vir and femina models of homo sapiens.

[Doctor Who reference, in case the above makes no sense to you.]

Although I may not have noticed the lack of an article, I did feel that "man" was a smaller subset of "mankind."

I have interpreted his statement as a contrast between physical effort it took to make an idea reality, as opposed to a goal many faithful believers supported and saw as a turning point in life as we knew it. "Here's the physical step man is taking onto the surface of the moon after doing all this research and manufacturing and preparation, and it represents a major triumph in human history that all people, even those who are not here on the moon, can be proud of."

Or, "I've achieved something for my group, but we can't take exclusive credit for such a historic moment."

A few years ago I met an Eastern European man who assured me that the whole moonwalk was cooked up in a television studio. He left his country to settle in the U.S., and it seemed to me that his childhood in a country in the Soviet bloc had predisposed him to reject the moonwalk. I wonder what he's thinking now — that that conspirator Armstrong is never going to come clean? How sad.

And by the way, my name is Jonathon, not Jonathan.

You can't trust people's memories; I realized that based on self-observation long ago, and everything science has learned in studying memory and the mind confirms it.

The comments here claiming that it made good sense without the "a" amuse me — people have a virtually infinite capacity for finding meaning where there is no apparent ground for it (cf. people who think "gray" is different from "grey").

But he maintained that he didn't think he'd missed the "a", and only realised he had when he heard the tape, so that weakens my theory somewhat!

He penned something cute: poetically symmetrical and high-minded.

But the more natural (think of the setting - a ladder a few rungs short of a truly new world) enunciation would have been 'that's one small step for me, one giant leap for everybody'.

Anyone in such a bewildering but concrete/unique situation might baulk at the unnatural 'a man',

It seems to me that the gender-neutral usage of man was common until the late 1960s but it's very rare now. The default word for ‘any human’ nowadays is person (except in contexts where you want to distinguish them from non-human self-aware beings, e.g. theology, fantasy/science fiction, etc.). (Whenever I have to translate a Latin quotation to English, I invariably use person for homo and man for vir.)

Hearing the phrase "gave the go" made me wonder how many words or idioms came into common usage as a result of the publicity given to the US space program. I thought of a few examples some years ago, but now I can't recall them.

I remember looking up at the moon then. Those were optimistic times.

I remember speculating about what he was going to say. My friends and I were hoping it would be "It is made of green cheese!". But I have to admit the "one small step" line was much better.

Not many explorers have had their first words recorded. John Batman's "this will be the place for a village" was one, but we don't know that that was the first thing he said. Most of them were too busy to work on memorable sayings, I suppose.