Fantastic grouping of four blocks of four 4¢ Project Mercury postage stamps, each signed in ballpoint by a Project Gemini astronaut (most signing multiple times). Includes: Frank Borman (signed four times), Thomas Stafford (signed twice), James McDivitt (signed twice), and Charles Conrad (signed once). In very fine condition, with poor-to-moderate signature contrast against the dark blue background. Accompanied by a NASA Facts newsletter covering the Gemini Program.
