Nitpicker, Perfectionist
This page is the CodyCross answer for the clue below from Space Exploration, Group 916, Puzzle 1 (Mary Jackson).
Question
Nitpicker, Perfectionist
Answer
STICKLER
Word Meaning:
STICKLER — (now only Cornwall) A referee or adjudicator at a fight, wrestling match, duel, etc. who ensures fair play.
Definitions from Wiktionary.