DLR's four-legged robot Bert explores and monitors the unfamiliar environment. The Surface Avatar Experiment rehearsed an important scenario for future exploration missions on the Moon and Mars. Bert is being developed at the DLR Institute of Robotics and Mechatronics and can walk, trot, gallop, perform a passing gait and even climb. This enables him to cover long distances and at the same time move around in rough terrain or small caves.