CAPE CANAVERAL, Fla. -- In the Rocket Garden at NASA's Kennedy Space Center Visitor Complex in Florida, NASA's Deputy Director for Planetary Science, Jim Adams speaks to the audience in attendance for the United States Postal Service unveiling of two new stamps that commemorates the 50th anniversary of human spaceflight. One stamp commemorates NASA's Project Mercury and Alan Shepard's historic launch on May 5, 1961, aboard the spacecraft Freedom 7. The second stamp honors NASA's MESSENGER, which reached Mercury in March to become the first spacecraft to orbit the planet. The two missions frame a remarkable 50-year period in which America advanced space exploration through more than 1,500 crewed and uncrewed flights. Photo credit: NASA/Kim Shiflett KSC-2011-3295