On May 4, 2011, two new U.S. postage stamps commemorating 50 years of manned space flight were unveiled during a special event hosted by the Postal History Foundation, 920 N. First Ave. in Tucson.

The special ceremony was highlighted by remarks from Dr. Ann Sprague, a University of Arizona research scientist. Sprague is a member of the NASA science team involved with evaluating information currently being gathered about the planet Mercury from the unmanned MESSENGER spacecraft, shown on one of the two new "Forever" postage stamps. MESSENGER is conducting the first orbital study of our solar system's innermost planet.

The second stamp salutes the 50th anniversary of Project Mercury, NASA's first manned spaceflight program, and astronaut Alan Shepard's historic May 5, 1961, flight aboard the Freedom 7 spacecraft.

Items from the UA Lunar and Planetary Laboratory's collection of space mission artifacts and maps were also be on exhibit at the Postal History Foundation's Peggy Slusser Memorial Philatelic Library. These rarely-seen items include a giant 3-D map based on photographs taken of Mercury, and a globe detailing Mercury's geographic features, as known prior to the start of the MESSENGER's launch.

A special pictorial Tucson postmark was applied to envelopes and cards bearing the new stamps in celebration of the stamps' release.