Preliminary Human Factors Evaluations of Lunar Terrain Vehicle Design Concepts at NASA JSC

The National Aeronautics and Space Administration (NASA) has begun planning for an unpressurized transport vehicle for two suited crewmembers that can accommodate various payloads, some of which might include logistics modules, crew EVA consumables for Portable Life Support System (PLSS) recharge, and work packages (e.g., tanker package, solar power package). This new vehicle, which is a successor to the Apollo Lunar Roving Vehicle (LRV), is called the Lunar Terrain Vehicle (LTV). With several unique aspects of the Lunar South Pole region, the LTV will have a different vehicle configuration from the LRV in respect to suit interfaces, cockpit layout, hand controllers, seats, and translation aids. In addition to replicating the capabilities provided by the LRV, the LTV design will expand functionality in areas such as being reusable with a service life of approximately 10 years, ability to survive eclipse periods and periods of shadow, remote operations, ability to traverse uncrewed to points of interest, and interface with and/or deploy future science instruments or payloads. This paper discusses the first in a series of design testing for the LTV concept. The objective of the test protocol was to gather a preliminary understanding of a reference concept design and collect data, using an unpressurized/mockup suit, on all aspects and devices used for driving and operating the LTV with limited suit mobility. Specifically, the team evaluated suited ingress/egress on/off the vehicle, two seat design options (“Apollo Style Inspired” and “Leaning Post”), footrest placement, controller assembly design and usability, and protocols for more advanced testing. Using six engineering subjects with an anthropometric stature range of 30
^th
percentile female to 98
^th
percentile male, results indicated the volume of the LTV deck to ingress/egress was acceptable regardless of seat configuration. Side horizontal translations aids were acceptable with vertical aids needed near the seats. Of the two seat designs, the Apollo Inspired seat was easier to get into a seated position, more comfortable, and needed less adjustments when compared to the Leaning Post configuration. Both seat designs needed improved back adjustability to perform better testing resulting in improved recommendations on true seat angle. A major finding was additional volume needed between seated crewmembers' shoulders and arms to operate the vehicle safely and eliminate interference caused by the other crewmember. More design maturity was desirable in the footrest design and additional adjustability in all axes was required for the controller assemblies. Based on preliminary evaluation data collected from this study, the team will refine seat adjustability and arm rest spacing, add additional translation aids, test two ingress/egress strategies (front entry versus side entry), collect suited seated functional reach data, collect suited seated field-of-view (FOV) data, and retest the protocol in a pressurized planetary suit.