ARKS Missions is the system that is used for both your Daily and Weekly Missions, as well as your Main Missions for when you're making progress through the game.

Mission Types

ARKS Missions consists of the following mission types:

ARKS Missions
Main Missions Missions here get added as you make progress through the game story and other game content.
Completing them in order will teach you more about advancing through the game.
Main Missions can also be tracked to show where you are meant to go to do them.
Daily Missions Missions that are updated daily.
Daily Missions are reset every day at 01:00 (PDT)
Weekly Missions Missions that are updated weekly.
Weekly Missions reset every wednesday at 01:00 (PDT)
Tier Missions These are missions in which you can earn Mission Pass Stars.
Tier Missions are reset every Wednesday at 01:00 (PDT) (Currently not in use.)