Armstrong prepared his famous
epigram on his own. In a post-flight press conference, he said that he chose the words "just prior to leaving the LM". In a 1983 interview in
Esquire magazine, he explained to
George Plimpton: "I always knew there was a good chance of being able to return to Earth, but I thought the chances of a successful touch down on the moon surface were about even money—fifty–fifty... Most people don't realize how difficult the mission was. So it didn't seem to me there was much point in thinking of something to say if we'd have to abort landing." Historian
Andrew Chaikin, who interviewed Armstrong in 1988 for his book
A Man on the Moon, disputed that Armstrong claimed to have conceived the line during the mission. People have speculated that the line was inspired by
The Hobbit by
J. R. R. Tolkien, in which
Bilbo Baggins's jump over
Gollum is described as "not a great leap for a man, but a leap in the dark". After leaving NASA in 1971 and moving to a farm in
Lebanon, Ohio, Armstrong named the farm "
Rivendell", a valley in Tolkien's works. In the 1990s Armstrong also had email address related to Tolkien. Armstrong however said that it was only after Apollo 11 that he read the works of Tolkien. People have also speculated that the idea for the quote may have come from an April 19, 1969, memo by
Willis Shapley in which he wrote "the first lunar landing as an historic step forward for all mankind". Armstrong said that he did not remember reading the memo. Recordings of Armstrong's transmission do not provide evidence for the indefinite article "a" before "man", NASA and Armstrong insisted for years that static obscured it. Armstrong stated he would never make such a mistake, but after repeatedly listening to recordings, he eventually conceded he must have dropped the "a".
Peter Shann Ford, an Australian computer programmer, conducted a digital audio analysis and claims that Armstrong did say "a man", but the "a" was inaudible due to the limitations of communications technology of the time. Ford and
James R. Hansen, Armstrong's authorized biographer, presented these findings to Armstrong and NASA representatives, who conducted their own analysis. Armstrong found Ford's analysis "persuasive". Linguists
David Beaver and
Mark Liberman wrote of their skepticism of Ford's claims on the blog
Language Log. A 2016 peer-reviewed study again concluded Armstrong had included the article. NASA's transcript continues to show the "a" in parentheses. == Protection by Armstrong ==