From the Movies
Specially designed for deep space exploration, and reconnaissance, probe droids are employed in science and military applications. They gather data and transmit it to their masters over vast distances. Tenacious hunters and searchers, probe droids (or probots) have a variety of sensors, and the ones employed by the Empire are armed with powerful blasters and, in some models, shields.
Most probots are launched in one-way pods which transport the droids to their target locations. Once there, they gather information. If confronted with a hazard, the droids can protect themselves. If confronted after their main mission has been completed these droids can selfdestruct.
Imperial probes are vaguely arachnid in shape, with a dark metal finish, bulbous sensor "eyes" and spindly manipulator arms. They hover along on repulsorlift engines, with their arms touching the ground to gather samples. After the Battle of Yavin, the Empire dispatched thousands of probe droids to hunt down the Rebel base. One of these droids eventually revealed the hidden base on the ice planet Hoth.
From the Expanded Universe
In the days of the Old Republic the probot was a tool of peace, an important technological advance that changed the face of the exploration being carried out deep in the unknown reaches of the galaxy. The first probe droids were developed 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.
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 Arakyd Industries Viper model of probe droid is one of the most common models in the Imperial arsenal. Lord Vader personally supervised the upgrade of the Viper series for tracking down the Rebel fugitives.
Behind the Scenes
Joe Johnston, in collaboration with Ralph McQuarrie, developed the look of the probot. The droid was built as an articulated miniature by Industrial Light & Magic and as a full-sized prop. For shots of it in full motion, like its flight away from its landing site, it was a miniature filmed in front of bluescreen. For its confrontation with Han Solo and Chewbacca, it was the full-sized unit. The miniature was 63 centimeters tall.
