In the previous year, we have performed three separate experiments. At NASA JSC, the tilt-translation sled (TTS) was used to study the effect of our advanced countermeasure prototype display on manual control piloting performance. Performance was measured in a series of different motion paradigms designed to provide motion cues as might be experienced by a microgravity adapted astronaut flying a lunar lander vehicle. First a "critical tracking task" was studied in which the pilot attempted to keep an unstable vehicle upright. Next a "hover task" was studied in which the pilot attempted to keep the vehicle at a fixed horizontal position. Both of the tasks were done only in the pitch/fore-aft direction. A human subject experiment was performed in which manual control performance was consistently greater with the prototype display, with > 70% reduction in root-mean-square error. At the U.S. Army Aeromedical Research Laboratory, the UH-60 helicopter simulator was utilized to study the effect of lunar dust blowback on pilot perceptions of vehicle orientation during the final stages of landing. The dust characteristics in the visual database were modified to more closely resemble the attributes of lunar dust inferred from Apollo landing videos and the cockpit was modified to mimic the forward window fields-of-view from the Apollo Lunar Module. In the experiment subjects reported their perceived orientation (pitch and roll) and horizontal velocity (direction and magnitude) during simulated lunar landings. Different levels of dust blowback were simulated and compared to cases where the subject had no visual cues or when the subject was provided an instrument display. Subjects often misperceived their orientation during landings, particularly when dust blowback obscured visual out-the-window cues. Finally, we have begun an experimental study of the effect of gravity on human perception of orientation. In cooperation with the National AeroSpace Training and Research (NASTAR) Center, we are using centrifuge-induced hyper-gravity as an altered gravity test-bed. In the experiment, subjects report their perceived orientation during roll tilts presented at 1, 1.5, and 2 Earth Gs. The roll tilts are presented over a range of angles and rotation rates or frequencies. Subjects report their perceptions using a somatosensory indicator, which they attempt to align with their perceived horizontal while in the dark. This technique allows us to study spatial orientation perception during dynamic roll tilts. Preliminary results indicate that while the typical overestimation characteristic of static tilt perception in hyper-gravity (G-Excess illusion) is present during dynamic tilts, sensory integration reduces the magnitude of overestimation. This is important in understanding how the altered gravity levels experienced during space exploration missions may impact astronaut perceptions of vehicle orientation.More »
Our goal is to determine the limits of human performance under likely extra-terrestrial landing conditions that may cause spatial disorientation. This contributes to a better understanding of visual and vestibular conditions contributing to spatial disorientation during landing and the resulting effects on human manual control. We have worked on demonstrating display and control system interfaces to reduce pilot workload, improve situation awareness, and mitigate spatial disorientation to ensure a safe crewed lunar landing. Finally, the work may also have terrestrial applications in mitigating the risk of helicopter accidents by suggesting new techniques to address problems associated with brownout during landing. In particular the "achievability contour" display being prototyped may have applications in helicopter flight planning, coping with brownout, as well as mission management aspects for guiding air-drops to locations given current environmental conditions (e.g., wind, air density). This display concept can be used for any energy-constrained terrestrial approach or landing. The Observer vestibular-visual spatial orientation model has been used to predict astronaut perceptions during lunar landing motions. This work in applying this model to vehicle trajectories has applications for terrestrial vehicles as well. The vehicle motions experienced during terrestrial accidents can be simulated in the model to determine if spatial disorientation may have played a role. Advances in the understanding of the role of motion cues and visual surround will contribute to aviator training relevant to spatial disorientation.More »
|Organizations Performing Work||Role||Type||Location|
|Johnson Space Center (JSC)||Lead Organization||NASA Center||Houston, TX|
This is a historic project that was completed before the creation of TechPort on October 1, 2012. Available data has been included. This record may contain less data than currently active projects.