Yeah, Jay, do you have a citation for your claim?
Whenever someone mentions that no one knew about Tranquility Base, they NEVER give a citation for it. Considering that Armstrong, Aldrin, and Duke have been quoted about just about every tiny detail about the mission, I can't imagine no one can list an actual quote from Duke saying it was a surprise, unless it's not true.
In Andrew Chaikin's book "A Man on the Moon", he states that Armstrong and Aldin did tell Duke, specifically so he wouldn't be confused by something he might not understand:
'For the landing, Armstrong gave some thought to quotes; before the flight he and Aldrin decided that if they reached the lunar surface they would use the call sign "Tranquility Base"--"base" to connote exploration. They told only Charlie Duke, lest the first words from the moon take him by surprise--"Say again, Apollo 11?" And when it finally happened, Armstrong found himself adding quite spontaneously, "The Eagle has landed."'
--Andrew Chaikin, A Man on the Moon, Penguin (London 1998), p. 623 (Author's note to page 206).
Unfortunately, Chaikin didn't really cite where his information came from either, but he interviewed just about everyone involved with Apollo for that book, and it's widely considered THE definitive book about the Apollo missions. So, with the lack of citations either way, I tend to believe Chaikin...
