Handling Qualities Evaluation of Pilot Tools for Spacecraft Docking in Earth Orbit

A piloted simulation was conducted to study handling qualities for the final phase of spacecraft docking in Earth orbit. Twelve evaluation pilots, including 10 pilot astronauts, provided Cooper-Harper ratings, Task Load Index ratings, and qualitative comments. The piloting task was manual translational control with automatic attitude hold during the final 10 ft of docking approach until the docking ports made contact. A previous study established that with conventional translational control, handling qualities for this task degrade significantly as the level of translation-into-rotation coupling increases. The goal of the present study was to evaluate the efficacy of various pilot tools designed to mitigate the handling qualities degradation caused by this coupling. Four pilot tools were evaluated: dead band indicator, flight path marker, translational flight director, and feed forward control. These pilot tools improved handling qualities, generally with greater improvements resulting from using these tools in combination. A key result of this study is that feed forward control effectively counteracts coupling effects while significantly decreasing propellant consumption, providing satisfactory handling qualities for the spacecraft configuration evaluated.