Dave Scott, Jim Irwin, and Al Worden were the Apollo 12 backup crew supporting Pete Conrad as commander, Al Bean as lunar module pilot, and Dick Gordon as command module pilot respectively. For Scott, being in charge of assembling the checklists was too good an opportunity.
Scott, Irwin, and Worden spent a fair bit of time flipping through the Conrad and Bean's checklists figuring out where to put in gags. They added a few cartoons and deliberately misspelled "albedo" as "albeano" in Bean's checklist. But it was the pictures they added that really caught the crew's attention.
A little over two and a half hours into their first EVA on the moon, Bean flipped to the page in his checklist that described the stages for taking a core tube sample. On the facing page was Cynthia Myers, Playboy's pick for Miss December 1969. Under the picture was the caption "Don't forget – Describe the protuberances."
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He stopped in his tracks and beckoned Conrad to come look. The two astronauts, a quarter of a million miles away, stopped what they were doing and started flipping through their checklists to see what other young women's pictures had accompanied them to the lunar surface. Conrad found Angela Dorian, Miss September 1967 over the caption "Seen any interesting hills and valleys?" and Miss October 1967 Reagan Wilson listed as his "Preferred tether partner." Bean found Myers was accompanied by Leslie Bianchini, Miss January 1969. He was instructed to "Survey – her activity."
The backup crew had pulled the pictures from a newsstand magazine, had then shrunk and printed on fireproof plastic coated paper to slip them into the checklists. Gordon, orbiting the moon alone at that point, wasn't left out of the joke. Playboy Playmate DeDe Lind, Miss August 1967 was affixed to the inside of a spacecraft locker prior to launch. Lind's picture, the sole personal memento Gordon kept from the flight, was put up for auction last year.
Conrad and Bean had the presence of mind not to say anything about the Playmates when they found the pictures. They figured that the American taxpayers listening to their lunar banter across the country wouldn't want to hear that national heroes were girl-watching on the moon.
Pranks on crews have certainly not disappeared from NASA's culture since the Apollo era, though modern jokes might take a different form. It's unclear how much girl watching goes on aboard the International Space Station, however. (As a side note, I feel like female astronauts would be outraged if a backup crew snuck playboy pinups into a spacecraft!)
Image: Playmate Angela Dorian, Miss September 1967 from the Apollo 12 CDR Cuff Checklist (scanned and uncensored photos). Credit: NASA