"Exploration Unit. Ideal for scouting the terrain, opposing forces, and alien activity. Its light Combat Strength gives it modest defense, but it is not suited to full-scale warfare."
This is an exploration unit that can scout terrain and construct Expeditions to investigate alien ruins, bones, or other features. An Expedition takes 10 or less turns to construct. The Explorer has 1 "Expedition Module" which is expended when an Expedition is constructed; Explorer itself is not consumed when this is used, and can reload modules by returning to any friendly city. There are quest rewards, a Prosperity Virtue and a Supremacy affinity level reward which increases the number of Expedition Modules that can be carried. Expeditions will take longer to complete in forested areas. If an Explorer abandons an Expedition before it is completed, the progress is retained (if that or another Explorer goes back to try again).
When ordered to go somewhere, the explorer will sometimes end its turn inside of miasma instead of going around it. To avoid your unit taking damage and possibly dying, you have to be certain to aim its course properly. If set to explore automatically, it will get too close to alien nests instead of avoiding them, and may also have trouble if there is an impassable mountain on the terrain causing its search pattern to be rather inefficient(goes to the top, but decides not to go farther on the only opening on the map, but instead circles back to an area already explored).
In Rising Tide, with the expansion of Aquatic Gameplay, Explorers can do expeditions on the seas as well, excavating Sunken vessels, crashed Spaceships, crashed Colonist Landers, Progenitor Devices and even Kraken Nests.
Early in the Harmony progression in Rising Tide, Explorers become able to 'Leash' non-colossal aliens, turning them into members of your army, without the upkeep cost. Most land creatures are unable to embark. Captured siege worms can. Researching Alien Domestication later allows Explorers to Leash colossal aliens as well.
Note: Leashing Aliens causes the Explorer to take moderate damage, depending on the strength of the alien leashed, which is also true for military units if you complete the Strength and Decay Marvel Quest.
Explorers act as scouts for their colony. They can move quickly through the world, clearing the fog of war, in order to bring knowledge to their people. However, whereas a scout would care only for knowledge of the present, an Explorer is devoted to uncovering the past. At their core, they are archeologists, skilled in excavation. They can delve into derelict settlements, progenitor ruins, alien worm skeletons, even crashed satellites, providing their colony with certain bonuses.