Evaluation of head-up displays for teleoperated rendezvous & docking

Rendezvous & Docking will be an essential part for many future spaceflight activities, like manned or unmanned exploration of the Moon or Near Earth Objects (NEOs), a Mars Sample Return mission, as well as On-Orbit Servicing or Space Debris Removal activities. While autonomy is expected to play a major role in future Rendezvous & Docking, human operators on the ground will still perform either real-time monitoring or actual control of the interceptor vehicle during its final approach. In order to enable the operator to perform these functions effectively and safely, a proximity operations Head-Up Display (HUD) was designed, providing attitude and trajectory prediction information in a number of different attitude projections, coordinate systems and display methods. The different configurations were compared in user studies to evaluate their performance in a number of test scenarios. The results show that an attitude HUD is a valuable addition to a teleoperation man-machine interface, with the outside-in attitude representation showing the greatest benefit for operator efficiency. The choice of coordinate system however has a small effect on the quality of target relative position estimates. Operators perform marginally better using a reference system based on the local horizontal plane than with one using the orbital plane. The different trajectory prediction display methods evaluated cause no measurable difference in maneuver guidance efficiency.