Space Cover 316: Glenn Mercury Flight NASA LocationsMany NASA locations were involved in the Project Mercury program. Many of these NASA locations did not have any covers created for them until the Schirra and Cooper flights. Covers from some of the tracking stations for those flights sell in the $15-$20 range.
There are a number of NASA location covers you can find in the FDC box for John Glenn's flight. With the Project Mercury stamp being released right after the completion of his flight there was a rush to the post offices to acquire stamps and get them cancelled for the flight. Luckily, many of the 305 post offices that had the secret package of stamps were close to NASA locations and thus cancels for those cities can be found.
In addition to the Cape Canaveral official FDI covers where the launch took place covers with Project Mercury unofficial FDI cancels can be found for others NASA cities such as: (1) Cleveland, OH - Astronaut training to handle a spinning spacecraft in the Lewis Flight Propulsion Laboratory, (2) Corpus Cristi, TX – Project Mercury tracking station, (3) Honolulu, HI – Project Mercury tracking station located at Waimea, HI, (4) Houston, TX – NASA started working on astronaut move to Houston in 1961, (5) Huntsville, AL – Redstone and Atlas rocket development, (6) St. Louis, MO – McDonnell Aircraft Company plant that built the Mercury spacecraft, (7) Washington, DC – location of NASA headquaters.
Some of these such as Corpus Cristi and Huntsville can be found with Project Mercury cachets. So next time you are at a stamp show you might want to check out the Project Mercury FDCs.