Probe droids (also known as probots or recon droids) were droids that were specifically designed and programmed to perform reconnaissance duties. These units were often dispatched by various space navies to gather information from a variety of different locations, reporting anything of significance as defined by specific preprogrammed protocols. Some models were equipped with a self-destruct mechanism in order to prevent those whom it had been sent to observe from studying them and determining their source, as well as a small blaster-type weapon for defense.
In the days of the Galactic Republic, probe droids were used as tools of peaceful exploration, important technological advances that changed the face of deep-space understanding. They opened up the way for mapping the unknown reaches of the galaxy. The first probe droids were developed and produced by Galalloy Industries to search planets and asteroids for valuable resources, such as metals to fuel the processing plants of industry. Probots later helped to expand the Republic's frontiers. By the time of the Galactic Civil War, many probots were employed for military functions by the Galactic Empire, as exploration had been severely limited by direct Imperial order.
Prior to the development of probots, remote probes had done the majority of mechanized exploration. These were comparatively simple machines, equipped with onboard computers and sensors. However, they were programmed to follow a carefully limited set of parameters and lacked the intelligence for true initiative or understanding.
The first probe droids were marvels of technological achievement, a single unit capable of doing the work of a team of scientists. Incredible amounts of unexplored territory were thoroughly mapped and charted by these machines during the days of the Galactic Republic.
Since deep-space exploration was put on hold by the Empire, probe droids were retooled and reprogrammed for search and patrol missions. Many droids were posted along the perimeters of key strategic star systems or hyperlanes, serving as automated guardians. Some were remote surveillance droids, observing the amazing array of communication bandwidths and relaying that information to Imperial Intelligence's Analysis Bureau.
A great number of probe droids were reprogrammed for deep-space scouting. Their mission, rather than to catalog new worlds, was to uncover unregistered settlements, with a priority on finding bases of the Alliance to Restore the Republic. Knowing how quickly Rebels could evacuate upon discovery, many probe droids were equipped with high-frequency HoloNet transceivers to immediately relay information. Other added features included advanced scanning equipment, visual and audio monitoring systems, stealth sensor scramblers, a blaster cannon, and built-in self-destruct programming.
As time went on, probot manufacturers began developing droids specifically for Imperial military applications, most notably Arakyd Industries. The resulting probe droids were faster, more lethal and much more efficient at snuffing out Rebels.