Perimeter patrol robots. RATLER (Robotic All Terrain Lunar Exploration Rover) robots on patrol. These small, wheeled robots were initially designed as prototypes for a lunar exploration mission. However, they are now used for conducting perimeter patrols, in surveillance, and in search and rescue missions. The RATLER robots are lightweight, manoeuvrable and can navigate over long distances. The RATLERS were built at the Sandia National Laboratories, Albuquerque, New Mexico, USA.