This paper presents development of a simulator for orbital missions to transfer unmanned orbital cargo to the International Space Station (ISS). In the missions, capture in enclosed region is adopted as grasping mechanism. Since this capturing method is safer and more reliable in space, future orbital missions will adopt this method. However, it is still necessary to analyze and ensure the safe capturing operation in advance. Therefore, the simulation on ground is definitely required for not only behavior analysis of the capturing of the orbital target but also verification of contingencies and their avoidance methods. In this paper, we construct a hybrid motion simulator for the mission to capture the H-II Transfer Vehicle (HTV). Then we simulate several cases of accidental capturing at the HTV mission and analyze the results.