In recent years, sample returns from celestial bodies have remarkably developed as important elements of space exploration. The targets are becoming increasingly distant celestial bodies. Improving mission flexibility and reducing risk are important in deep-space exploration. The deep-space orbital transfer vehicle concept, which separates the sampled child spacecraft from the parent spacecraft that navigates between celestial bodies, has been proposed as a solution. The key technology of such a system is the autonomous docking in deep space. The docking mechanism must have low resource requirement, high success rate, and low guidance control requirements. The authors propose a novel docking mechanism with high capacity for positional errors. The mechanism has claws that can cage a grapple fixture, after the initial contact, using spring force and then fix it by driving a motor. This paper presents the concepts, requirements, and design of such a docking mechanism. Subsequently, evaluation using a prototype model is discussed.

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