Drones are small unmanned ships used by larger vessels to augment a ship's sensor efficiency, and when needed defend the ship from enemy attack. These devices link to the ship they belong to and with each other; however, since drones are designed to be relatively small, they rarely possess sophisticated command and control functions. They are most effective when directed by an Artificial Intelligence. It is for this reason that drone technology was primarily used during the pre-Fall period, before the cultural and scientific horrors of the Long Night. There are 2 main types of drones, Combat Drones and Sensor Drones. Depending on the model, there is a degree of overlap between the 2 types.
Drones have a huge variety of uses and a wide range of applications. They are used for communications between a network of ships in a sector of a galaxy, as messengers over long distances to transmit distress calls, mail, and civilian messages. As an interconnected system of sensors that act to extend the range of a military vessel, or to defend a vessel from minor threats and to make a combat group or an individual ship more versatile. The combinations are almost endless. For example, the Andromeda Ascendant uses her drones to help her create a very large sphere in the space around her, which, when combined with the sensor capabilities of her sensor drones, helps to make an extremely information rich network-centric environment. This ship, like many others, also uses her combat drones to take out smaller missiles coming at her from a distance. The Knights of Genetic Purity have also been known to deploy combat drones called Seraphim drones, which provide their Seraphim cruisers with an array of defensive and offensive advantages other ships may not have.
Sensor Drones are non-sentient, disarmed, drones that many High Guard ships use to extend their sensor range. The Andromeda Ascendant carries about a dozen drones on board, and she uses these drones when she is searching for something or surveying a large area of space. While the Andromeda Ascendant herself has a large on board sensor array, it can be limited. So, when she needs to extend her range, she deploys the drones so that she can get a live picture relayed to her from the drones, or she can deploy them in a rough circle at the very edge of her sensor capabilities. Since the drones themselves possess powerful sensors, they can probe and see a lot farther that the Andromeda Ascendant's sensors, and they relay this data back to her. She can use this to gather data about a battle and then plan and attack accordingly, or any other imaginable usage.
These kinds of drones are usually only carried by large ships, because they require to be docked when not in use, and the drones are large, so not many smaller vessels can accommodate one drone, not to mention the dozen that the Andromeda carries. Also, the facilities are needed to fuel, repair, and rearm drones, so only large ships with the ability to refuel and the ability to create repair nanites, and to house such drones.
The limitations of drones are mostly logistical. The drones need to be docked when they are not in use, and need to be refueled constantly, because they do not have an onboard reactor. As a consequence of their constant maneuverability, they use up the little fuel they have very quickly. Also, the type of ship that carries drones has to be large in order to carry a sufficient quantity of them to be effective, and with a large amount of drones comes the need to rebuild, create, and repair them, which requires a lot of resources, something which many starships cannot afford to expend. Furthermore, even attack drones are relatively small when compared to other ships, and thus are not able to carry effective defenses on their own and remain armed and/or maneuverable.
The interconnected operating systems drones generally rely on also pose a potential problem, due to the less than secure nature of automated computer networks. An enemy vessel with advanced electronic counter measure capabilities could theoretically hack the enemy drones, or even the ship that manages them. This means that High Guard vessels, which often possess complex artificial intelligence command and control features, are able to ensure and thwart enemy intrusion into to their private network, however most do not, adding another potential drawback to the use of drones.