Collector is a ship upgrade found on some barge-type derelicts. This upgrade is always permanently installed, and therefore can not be towed. Once a vessel with the collector upgrade has been commandeered it will be available to the player. The upgrade can NOT be scrapped or uninstalled from the ship (essentially blocking a ship upgrade slot), but also never deteriorates.
The collector upgrade is passive and does not have to be activated to work (and because of this the help page of this upgrade is never unlocked in version 1.00)
The effect is the following: All useful objects that can be sucked into space (i.e. Scrap, disabled Drones, working Drones and Ship Upgrades) have a certain chance (around 5 out of 12 times) to be caught by the collector and returned to the ship inventory at the end of the mission.
As a general rule of thumb, try commandeering larger vessels (dictated by A,B,C,D beside the vessels name), as they have more upgrade slots and thus have a much higher chance to have the collector upgrade, alongside other perks such as higher scrap storage capacity.