navigator vs astrogator

navigator and astrogator both are nouns.

Word	Noun	Adjective	Verb	Adverb
navigator	Yes	No	No	No
astrogator	Yes	No	No	No

As nouns, astrogator is a hyponym of navigator; that is, astrogator is a word with a more specific, narrower meaning than navigator:

navigator: the member of an aircrew who is responsible for the aircraft's course
astrogator: the navigator of a spacecraft

navigator (noun)	astrogator (noun)
in earlier times, a person who explored by ship	the navigator of a spacecraft
the member of an aircrew who is responsible for the aircraft's course
the ship's officer in charge of navigation