From Outscape Wiki
Freighters are a versatile service vessel class and an empire's workhorse. They can be configured to perform as cargo vessels, fuel tankers or personnel transport. For their size, they are relatively cheap and lack armour. Few freighter hulls are compatible with weapons. In-Game Description
Players can unlock their first freighter-class hulls very early on, but larger variants will not be unlocked until the mid-game. As a player's empire grows, they will likely need many logistics fleets of freighters to move cargo, fuel and colonists around their empire. Their data are summarised on the Freighter page.