Rocket-propelled exploration robot: Shooting scouter, concept and evaluation of flight dynamics

This paper presents the concept and evaluation of flight dynamics for the small sized rocket-propelled exploration robot, “Shooting Scouter”. Most of the planetary rovers are actuated by the wheels, causing their velocity limited by the electrical power restriction and the heat exhausting efficiency of the motors. Also the locomotion distance is strongly influenced by features of the terrain of the planetary surfaces. To realize the system capable of improving those problems, we focused on the rocket propellant and proposed the robot named Shooting Scouter. Due to the rocket propellant, Shooting Scouter's locomotion is not influenced by features of the terrain. In addition, according to the launching payload capacity of the launching rocket, small-sized lightweight actuators have the advantage of a low launching cost. However, a small-sized lightweight airframe causes a higher sensitivity for the deviation of the center of gravity, resulting in loss of control and missing the target site. This paper presents the evaluation of flight dynamics of Shooting Scouter and presents technologies to land Shooting Scouter on the target site, that can be used in space environment. One of the technologies is to stabilize the attitude during the flight. We focused on the technology to stabilize the attitude of the spinning satellite. The function to spin the reaction wheel inside the airframe is integrated on the design of Shooting Scouter, while the reaction force of the wheel is employed for the post-landing locomotion. The other technology is to improve accuracy of flying direction and distance by managing the center of gravity. A simplified center of gravity measuring device is developed to calibrate the deviation. Our experimental results show these technologies achieved stabilizing attitude during the flight and reduced the landing point error of Shooting Scouter.