Argonaut is a noun that refers to an adventurer on a quest. 

Fans of Greek Mythology may be familiar with the Argonauts, a group of heroes who accompanied Jason on board the ship Argo in the quest for the Golden Fleece. But since the 17th century, the word Argonaut has been used more broadly by English speakers to describe anyone engaged in an adventurous quest, for example:

Those Argonauts in the shipping department have been trying to beat us in the annual darts tournament for years. But as long they face our office in the competition’s final round, their quest for immortality will be denied.