Somewhere, I have 4 or 6 of these stamps, uncanceled, that I bought on February 21, 1962. "U.S. #1193 features the “Friendship 7” space capsule flown by John Glenn in the first successful orbit of the Earth. The mission was the result of a secret project run by the Post Office Department. The Post Office had recently (at the time) started using a Giori Printing Press, which allowed it to produce stamps in two or three colors in a single run (instead of having to send the stamps through for each color)". "In the summer of 1961, the Post Office Department began a special project. The new Giori Press was locked in a separate room accessed only by a small number of postal employees and with a guard to keep others out. No written instructions were given for the project. Rumors in the Department speculated that it was being used to make currency. Instead, it was printing the “Project Mercury” stamp". "The stamp was sent in sealed packets to postmasters in 305 locations around the country, with specific instructions: “Classified Material. Do Not Open.” The packets were shipped in time for the original launch date – December 21, 1961. Weather caused delays until the end of February". "The secrecy was connected to the planned flight of the “Friendship 7” capsule. The launch was at 9:48 a.m. local time in Cape Canaveral, Florida, and splashed down at 2:43 p.m. At 3:30 p.m., the post offices were informed by telephone,teletype, and telegraph, that they could open the packet and distribute the stamps. If there had been a failure, the stamps would not have been released". "One side effect of the late release was that it gave very limited time to get First Day Covers serviced – an hour and a half, in Eastern states. Cape Canaveral is listed as the official site of the First Day of Issue. There was no Cape Canaveral Post Office until 3:30 p.m., February 20, 1962. That’s when a U.S. Air Force van was made into a temporary post office and called a substation of the Cocoa, Florida, Post Office".