The future goal of lunar research is a functioning ISRU chain for the production of oxygen. In-situ resource utilization (ISRU) describes the use of lunar resources for product and material generation, without transporting material from Earth.The main steps of this process are excavation, conveying, beneficiation, and processing. Each of these subsections and their interaction must function properly to enable the production of oxygen, such as for rocket fuel and to be used within lunar bases. Excavation is the first important step herefore. Due to the prevailing conditions at the celestial body, such as low gravity and thin atmosphere, and also due to the powdery and abrasive surface material, called regolith, a common mining machine as used on Earth won´t work as intended. Thus a concept for a mining system that can handle these issues is developed in the course of this thesis. There are many different functional principles possible to enable excavation. After a comparison of different implementation possibilities and their advantages and disadvantages, a bucket excavator is set to focus as a promising concept for lunar excavation. The idea is to use a horizontal bucket chain excavator that is connected with one robot on each side of the main bridge system. Because of the low gravity, scrapping of the material such as with this excavator type is preferred generally. A carrier system consisting of three beams is designed to control the excavation process by setting the mining depth, and if required, the excavation angle during operation. With this concept, a relatively large area can be processed. It is in relation to various other concepts also beneficial regarding dust and energy requirements, and it is also feasible to be used for surface levelling, such as to prepare the ground for rocket launch/landing sides or lunar bases. The concept development is focused on mechanical aspects, which is also supported by numerical simulation, specifically to find a suitable bucket shape. An important function is also the discharging of the excavator for further conveying purposes. Due to lunar conditions, a notching/releasing mechanism at the bucket is implemented to enhance the excavation and especially the discharging process. With this mechanism, it is possible to decrease the time of ejection. A 3d model of the total concept is further presented, giving insight into the developed system, whereby special attention is paid to specific mechanical system components. This final system shows a promising concept that covers basic mechanical principles to allow lunar excavation as an option for further developments of excavation machines for lunar missions – but may also hold capabilities to be used in some specific application areas on Earth.