Proficiency Training and Retention for Manual Crew Override During Simulated Lunar Landing

BACKGROUND
Microgravity-induced alterations in vestibular sensory processing, coupled with potential limitations in just-in-time training availability, pose risk to the upcoming NASA Artemis mission architecture in the event of the crew needing to assume control during landing contingencies. The present work describes the development of a lunar landing simulation task integrated with a 6DOF motion system, based on planned HLS training, to enable quantification of microgravity effects on manual control performance during simulated lunar landings following spaceflight during the Manual Piloting study. The simulation requires the user to monitor an automatic flight trajectory before taking manual control of the spacecraft’s attitude and rate of descent to either the nominal or a re-designated landing aimpoint during the approach phase. Prior to testing the flight crew, it was important to validate the ground training curriculum, training frequency, and the number of sessions required to gain proficiency.

OBJECTIVES
This ground study aimed to quantify the rate of skill acquisition in first-time users of the lunar landing simulation, as well as the retention of those skills after a four-month period of non-use. The present work characterizes user performance under nominal sensorimotor conditions to establish baseline proficiency and to refine training objectives.

METHODS
Thirty healthy, non-astronaut volunteers completed five one-hour sessions using the six-degree-of-freedom motion base paired with the lunar landing simulation. Eleven participants reported prior piloting experience, including those pursuing a private pilot license and those who had obtained a license and/or additional certifications such as an instrument rating. The remaining 19 participants reported no piloting experience. Twenty-six participants reported prior gaming or simulation experience. The first four sessions, conducted weekly over one month, focused on training and characterizing skill proficiency, while the fifth session, performed four months later, assessed skill retention. The first session emphasized familiarization with the simulation software, including interface definitions, hand controller inputs, and hands-on practice with trials of varying difficulty. A gradual training approach was used, beginning with observation of automated landings, followed by single-controller practice, and culminating in the full task with both rotational and translation controller inputs and secondary monitoring tasks. Sessions two through four were focused on deepening piloting proficiency with instructor feedback, as needed. Piloting proficiency was evaluated based on touchdown performance and the pilot’s ability to follow a guidance algorithm during approach. Up to twelve simulated lunar landing trials were completed per session. Gaze-tracking glasses were used to quantify users’ visual scanning behavior.

RESULTS
Most performance metrics showed significant changes in proficiency across training sessions, indicating continued learning across subsequent sessions. Certain metrics met the established criteria for a successful landing by the first or second session, whereas others took up to three sessions to reach proficiency. Following the four-month hiatus, many measures were retained, with no significant degradation in median performance, while a subset of the measures showed partial loss of proficiency, suggesting differential retention across performance domains. Several participants were unsuccessful on the first landing trial of the retention session and required additional trials to regain proficiency, underscoring the importance of skill recency and just-in-time training in operationally relevant tasks. Gaze data suggest improved visual scanning efficiency, indicated by shorter fixation durations.

RELEVANCE
The results from this ground research informed the protocol development of a flight study with ISS crewmembers and demonstrated the average number of sessions required to gain proficiency with participants of varying piloting experience. The flight study will deliver an operational demonstration of simulated landing manual control capability following spaceflight to identify any deficits that require remediation. The findings of this study identify key performance domains that should be incorporated into ground and in-flight training platforms to ensure the retention of skills required for successful manual crew override.

ACKNOWLEDGEMENTS: The authors acknowledge contributions from the Charles Stark Draper Laboratory, the Dynamic Skills Trainer (DST) Lab, and the Crewed HLS Interfaces for Piloting Working Group (CHIP-WG) developing lunar landing simulation platforms. This project is funded by the Human Health Countermeasures Element.