Crossword clues for the word: PROJECTMERCURY The word PROJECTMERCURY has appeared as an answer to at least 3 crossword clues on different crossword puzzles. Crossword clues for PROJECTMERCURY Showing 1 to 3 of 3 results Clue(s) First manned-spaceflight program in the United States Man-in-space undertaking Subject of a 1962 commemorative stamp