Armstrong's 1969 Moon step and the still-missing 'a'

Neil Armstrong became the first person to step onto the Moon at about 02:56 UTC on July 21, 1969 (10:56 p.m. EDT on July 20 in the United States), when he set his left foot on the Sea of Tranquility beside the lunar module Eagle. More than half a billion people were watching on television.

Did he say “a man”?

What the world heard was “That’s one small step for man, one giant leap for mankind”. After the flight Armstrong said he had meant to say “one small step for a man” and believed he had, though he agreed the “a” could not be heard on the recordings.

In 2006, journalist Peter Shann Ford claimed to have found the missing word in the waveform of the transmission. The Apollo Lunar Surface Journal, NASA’s annotated record of the moonwalks, reports that more rigorous analyses by audio specialists, using spectrograms, did not support him. The Journal’s transcript honours Armstrong’s intent, and published versions still differ: NASA’s history office prints the line with the “a”, while the Smithsonian’s Apollo 11 timeline leaves it out.

The step came first

The famous sentence was not spoken as his boot touched down. Timing the transmissions against the hatch-opening time in the Apollo 11 Mission Report, the Journal’s editors place the step about six seconds before he began the line. They also note that the raw NASA transcript’s timestamp for it is inconsistent with the surrounding audio, which is why published times for the first step differ.

Buzz Aldrin followed about 20 minutes later and called the view “magnificent desolation”, while Michael Collins orbited alone in Columbia. The two moonwalkers spent roughly two and a half hours outside, walking about 3,300 feet in total and never straying more than 200 feet from Eagle.