In this note, a prototype design of the navigation control system for an unmanned spacecraft in a planet is presented. In the process of automatic landing, the spacecraft must sense its location with the map data prepared in advance for localization and navigation. For spacecraft landing mission, selection of a place with a gentle terrain suitable for landing and then complete it within an acceptable error will be taken as the first important target. However, in the lunar space environment, the sensors required by general aircraft such as the Global Position System (GPS), magnetometer, and barometer will all fail so that it is difficult to establish a heading and attitude reference system. Therefore, in order to achieve the spacecraft planet landing, the vehicle must have the capability of finding the location of itself through sensors and compare the characteristics of topography and landforms for localization. To this demand, in this study, a depth sensor is used as the information source for six degree of freedom (6-DoF) pose estimation. Its advantage is that it is not affected by the light source and has a high resolution for the depth information of the environment. In order to realize the concept of this research, a multi-axis motion platform is developed to simulate the motion of the spacecraft and the platform is also used as a pose reference to verify the feasibility of the proposed concept. Experiments have proved that the proposed localization algorithm can independently complete 6-DoF pose estimation without the assistance of external sensors, thereby achieving the goal of spacecraft localization and landing decision making.