John Glenn (1921–2016) is linked to one of modern U.S. postal history’s most interesting tales that will likely never be repeated. Here is the story, according to the Smithsonian National Postal Museum, with an excerpt below:
On February 20, 1962 , John Glenn became the first American to orbit the Earth. Minutes after his safe return, the Post Office released the Project Mercury stamp—the first U.S. commemorative stamp issued at the same time as the event it celebrated. It had been prepared in complete secrecy in case the mission did not succeed.
To keep the project quiet, the stamp’s designer worked from home while claiming to be on vacation. The picture engraver also gave the impression he was on leave, but came in at night. Another engraver did the lettering on weekends.
Just over 400 people knew the secret, about half of them postal inspectors. As the day approached, stamps were sent in sealed packages to 305 post offices, still a mystery even to the postmasters themselves.