“Neil Armstrong said "That's one small step for a man, one giant leap for mankind" on the moon.”

NASA's transcript renders the famous line as: “That's one small step for [a] man, one giant leap for mankind.” The brackets indicate the article was not clearly audible in the audio record, even though Armstrong said he intended the phrase to be “for a man.”

Neil Armstrong: "Okay. I’m going to step off the LM now. That’s one small step for man, one giant leap for mankind." ... This transcript is based on the audio of the Apollo 11 Moon landing broadcast and records Armstrong’s words without the article "a" before "man."

“Houston, Tranquility Base here, the Eagle has landed.” “That’s one small step for [a] man, one giant leap for mankind.” ... In July 1969, Apollo 11 astronauts Neil A. Armstrong, Michael Collins, and Edwin E. “Buzz” Aldrin completed humanity’s first landing on the Moon.

On July 20, 1969, Neil Armstrong became the first human to walk on the lunar surface. As he stepped onto the Moon, he uttered the now-famous words, “That’s one small step for man, one giant leap for mankind.” Armstrong later said he intended to say “for a man.”

Armstrong was the first person to walk on the moon. He famously referred to this achievement as “one small step for man, one giant leap for mankind.” However, Armstrong insisted that he actually said “one small step for a man,” and annotated the APS's copy of the transcript accordingly.

The trio was launched from Kennedy Space Center in Florida on July 16, 1969... The next day, July 21st, at 10:56pm, it would be Armstrong who would take that first historic step... Also long discussed is the exact wording of Armstrong’s first comments. Armstrong himself has long maintained that he said (or intended to say), “That’s one small step for a man, one giant leap …”.

Neil Armstrong and Edwin “Buzz” Aldrin Jr. made the landing; Michael Collins piloted the command module that returned the astronauts to Earth on July 24, 1969. The transcript of the Apollo 11 mission commentary includes Armstrong’s famous statement from the lunar surface, commonly quoted as “one small step for man, one giant leap for mankind,” though Armstrong later said he intended to say “for a man.”

Listeners back on Earth heard, “That's one small step for man, one giant leap for mankind.” But Armstrong, who died at the age of 82 on Saturday (Aug. 25), maintained afterwards that he actually said something slightly different: “That's one small step for a man…” “It's just that people just didn't hear [the 'a']," Neil Armstrong told the press after the Apollo 11 mission. In a graphical representation of sound waves of the famous sentence, Ford said he found evidence that the missing "a" had been spoken after all: It was a 35-millisecond-long bump of sound between "for" and "man" that would have been too brief for human ears to hear.

In NASA’s official transcript of the Apollo 11 landing, Armstrong’s words from the Moon are rendered: “That’s one small step for man, one giant leap for mankind.” Almost immediately, however, Armstrong said he had intended to say, and believed he actually said, “That’s one small step for a man.”

Millions on Earth who listened to him on TV or radio heard this: “That’s one small step for man, one giant leap for mankind.” But after returning from space, Armstrong said that wasn’t what he had planned to say. He said there was a lost word in his famous one-liner from the moon: “That’s one small step for ‘a’ man.’ It’s just that people just didn’t hear it.” During a 30th anniversary gathering in 1999, the Apollo 11 commander acknowledged that he didn’t hear himself say it either when he listened to the transmission from the July 20, 1969, moon landing. “The ‘a’ was intended,” Armstrong said. “I thought I said it.”

Those words became revealed when he reached the bottom of the lunar module's ladder: “That's one small step for man, one giant leap for mankind.” The problem with his little speech was the fact that Armstrong left out an indefinite article, “a”, before the word man. Armstrong maintained soon after returning to Earth that he had said the word a and that listeners at home just hadn't heard him or it had been drowned out by space static, though he modified his story in later decades and said he “intended” to say the missing article. Armstrong said he found Ford's argument “persuasive”, even though by that time he had been wavering in his denials to the point where he even told his biographer, James Hansen: “It doesn't sound like there was time for the word to be there.” Linguist David Beaver pretty much dismisses Ford's methodology and conclusions here.

Reporting on a computer analysis of the audio, ABC quotes researcher Peter Shann Ford as saying: “Mr Ford says high‑resolution analysis of the NASA recording shows that Armstrong did actually say ‘That’s one small step for a man, one giant leap for mankind.’ He says there is a 35‑millisecond long ‘a’ sound between ‘for’ and ‘man’ that is too short to be heard by humans in normal listening conditions.” This analysis is presented as evidence that Armstrong spoke the missing ‘a’.

The news clip explains: “Millions on Earth who listened to him on TV or radio heard this: ‘That’s one small step for man, one giant leap for mankind.’ But after returning from space, Armstrong said that wasn’t what he had planned to say. He said there was a lost word in his famous one‑liner from the moon: ‘That’s one small step for ‘a’ man.’ It’s just that people didn’t hear it.” The broadcast thus distinguishes between the heard version and Armstrong’s claimed intended wording.

Tom Foreman reports: “It’s one small step for man, the problem: the first part of his historic sentence, ‘That’s one small step for man,’ is grammatically incorrect; it should have been ‘one small step for a man,’ and that missing ‘a’ has been setting off grammarians ever since. Through all the years NASA has insisted that he did say the ‘a’ and modern microphones would have picked it up instead; the word was lost on scratchy old equipment operating nearly a quarter million miles away, and Armstrong… agreed with NASA.” The report then describes research on Midwestern U.S. speech patterns where “for” and “a” are often pushed together into a sound like “fra,” suggesting Armstrong’s dialect could explain why the “a” is hard to hear.

As he stepped onto the lunar surface, Armstrong said, “That’s one small step for [a] man, one giant leap for mankind.” The word “a,” supposedly spoken by Armstrong, was lost in the transmission, and in subsequent decades there was much discussion about whether he had actually said it. Armstrong maintained that he intended to say “a man,” and some later audio analyses have suggested that a very brief sound corresponding to the article may indeed be present in the original recording.

Historical and media accounts since 1969 almost universally quote Armstrong’s words as “That’s one small step for man, one giant leap for mankind,” reflecting what is heard on the original transmission and what appears in most official transcripts. However, Armstrong repeatedly stated in interviews that he intended to say “for a man,” and some later NASA and scholarly discussions acknowledge this intention while still citing the recorded version without the article.

The video explains that the audio was fuzzy and that the tiny “a” may have been lost in static. It also states that Armstrong himself insisted he intended to say “one small step for a man,” while acknowledging that listeners often hear only “for man.”