[PROJECT MERCURY]. Project Mercury First Day Cover. Approx. 3.5 x 6.5 in., unaddressed, postmarked Cape Canaveral, 20 February 1962. SIGNED BY SCOTT CARPENTER, GORDON COOPER, WALLY SCHIRRA, ALAN SHEPARD, AND D. K. SLAYTON. Commemorates the first day of issue for the 4-cent Project Mercury stamp, uncacheted.