Manual rendezvous and docking (manual RVD) is a challenging space task for astronauts.Previous research showed a correlation between spatial ability and manual RVD skillsamong participants at early stages of training, but paid less attention to experts.Therefore, this study tried to explore the role of spatial ability in manual RVD skills in twogroups of trainees, one relatively inexperienced and the other experienced operators.Additionally, mental rotation has been proven essential in RVD and was tested inthis study among 27 male participants, 15 novices, and 12 experts. The participantsperformed manual RVD tasks in a high fidelity simulator. Results showed that experiencemoderated the relation between mental rotation ability and manual RVD performance.On one hand, novices with high mental rotation ability tended to perform that RVD taskmore successfully; on the other hand, experts with high mental rotation ability showednot only no performance advantage in the final stage of the RVD task, but had certaindisadvantages in their earlier processes. Both theoretical and practical implications werediscussed.