Space Cover #48, Mercury Stamp FDC's Bob McLeod
On February 20, 1962, at 3:30 PM EST, shortly after John Glenn successfully completed his three orbits to become the first American to orbit the earth, 305 post offices around the country were notified by the United States Post Office to open secret packages shipped to them earlier.
Enclosed inside the secret packages were sheets of the 4 cent Project Mercury stamp and instructions to immediately put them on sale. The sudden sale of these stamps all across the country was the first time a US postage stamp was issued simultaneously with the event it commemorated.
After hearing the announcement, collectors and enthusiasts all across the USA scurried to local post offices to buy these new space stamps. Many Mercury stamps were put on covers and canceled for the stamp's First Day of Issue and some taken to other post offices to create so-called unofficial First Day Covers (FDC's).
However, because of the late-in-the-day availability of the stamps, only a limited number of covers were canceled around the country on the historic February 20, 1962 date, and Mercury FDCs from some of the 305 post offices have never been found. Also covers were canceled at a temporary one-day postal station near the launch site using the standard "First Day of Issue" cancel. Covers from the other 304 post offices were canceled with just regular post office hand stamp and machine cancels.
Enthusiasm for these Mercury FDC's resulted in many collectors actively searching for FDCs from all 305 cities and also unofficial cities. Collectors of that time were very active in buying and trading for needed Mercury FDC's. Of course, the fad eventually died down, but Mercury stamp FDC's from hundreds of US post offices are still sought after by some of today's collectors.
Shown here are Mercury FDC's from 4 of the 305 official cities. Because of no prior announcement of the "Surprise Stamps," no covers with Mercury cachets were available to use that day, so collectors used whatever cacheted, or blank, covers they had. Many of the blank, uncacheted, FDC's were later cacheted with Mercury Program cachets designed and applied after the flight, which 3 covers here illustrate.