On May 21, 1981, the Post Office released the Space Achievement commemorative issue, 18-cent stamps, in a block of eight format, one image being shared by four individual stamps, with four more aside them depicting various space exploration imagery. First day of issue occurred at the Kennedy Space Center, Florida. The four central stamps depict the Space Shuttle in its various modes of operation. The central theme of this issue involves the first actual 'in space' flights of the Space Shuttle and also pays tribute to twenty years of U.S. crewed space exploration. The other stamps to the left and right sides are honoring the efforts of those who partook in the historical Moon walk, Skylab, and Pioneer 11 missions. The images were modeled by Clarance Holbert. The stamp design by Robert T. McCall.
