On tapes of the Moon landings, he appears to drop the "a" from the famous quote: "That's one small step for a man, one giant leap for mankind."

But new analysis of the tapes has proved Mr Armstrong right after all. Computer programmer Peter Shann Ford used audio analysis software to show that the missing "a" was blotted out by transmission static.

But an analysis of the audio files downloaded from Nasa's website using GoldWave, a $45 (£24) audio editing program, indicates that the word was spoken but not recorded by Mr Armstrong's microphone...
A microphone DOES NOT RECORD anything.

"It's nice to know that what he thought he said, he actually did say, and that because of the nature of the electronic and the communications systems of the time, it just did not get through."
That's true, but overly general.

It you listen to the recording at the link above, it also sounds like "one diant [sic] leap for mankind." Did he flub that one too? Nah.