PIONEER
| Date | Clue |
|---|---|
| 2018-04-19 | First in a field |
| 2014-05-04 | First of a kind |
| 2013-04-22 | Daniel Boone, notably |
| 2012-01-19 | Innovator |
| 2011-12-20 | Davy Crockett, e.g. |
| 2008-11-18 | NASA program that explored the outer planets |
| 1998-06-27 | Avant-gardist |
| 1995-10-15 | Show the way |
| 1994-06-27 | Avant-gardist |