A discussion is presented of the utilization of hierarchical diagnosers for hierarchical event-based control systems for robot-controlled experiments aboard the forthcoming space station Freedom. The analysis was performed using discrete-event simulation. The hierarchical discrete-event model was implemented in DEVS/Scheme. The concepts are exemplified by the analysis of a general-purpose fluid-handling facility, which has been proposed for inclusion as one component, in the life science module. The proposed methodology will provide the laboratory robot with sufficient intelligence so that it can perform most of the needed tasks in a semiautonomous mode. Experiments can be remotely guided by the scientific investigator from the ground, thus minimizing the need for crew interaction.