Figure 1. Visual database in the VMS, depicting International Space Station and Crew Exploration Vehicle
SimLabs continues to examine critical issues related to space vehicle handling qualities in support of NASA's Exploration Systems Mission Directorate (ESMD). Handling qualities describe the ease and precision with which a pilot can execute a flying task and are affected by numerous issues, including vehicle response, guidance cues, and inceptors.
In this study, researchers focused on the Crew Exploration Vehicle (CEV), with specific emphasis on the relationship of the control system response to control power. Additionally, the effects of camera delay during docking were examined.
A Vertical Motion Simulator (VMS) cab has been customized to resemble the cockpit of a generic space capsule, representative of the CEV. In-house graphics specialists created a visual database of the International Space Station that depicts the new docking mechanism to be utilized by the CEV, known as the “Low Impact Docking System,” or “LIDS” (Figure 1).
Test subjects—including current and former astronauts and NASA test pilots—flew several docking scenarios wherein the vehicle’s translational control system was varied (continuous jets, pulse jets, proportional, or discrete) and combined with either zero, low, or high cross-axis coupling. Such coupling means that the commanded thrust vector could produce unintended motion effects.
Figure 2. Centerline camera view during docking maneuver showing guidance aid overlay
It is anticipated that the CEV will have a display in the cockpit which shows the centerline camera view during docking. Super-imposed guidance aids should make the docking task easier (Figure 2). However, excessive delay of the camera feed could be detrimental to the operation. Researchers experimented with delays of up to several seconds.
At the end of each simulation run, pilots provided Cooper-Harper ratings and Task Load Index ratings. Researchers are evaluating the data and will use their findings to provide design guidelines to NASA's Exploration Science Mission Directorate, ultimately benefiting the space vehicle program for several generations to come.