Date: August 2020.

Source: 50th International Conference on Environmental Systems (ICES) 2020.

Abstract: The Exploration Extravehicular Mobility Unit (xEMU) project is tasked with building a spacesuit for the lunar 2024 missions. These missions will require a mobile Lower Torso Assembly (LTA) to fit the required range of astronauts’ anthropometry with optimal mobility. The goal of this work was to develop a quantitative framework to assess the new LTA brief designs for the anthropometry and mobility requirements. Initially, virtual fit checks were conducted via computer-aided design (CAD) modeling. Body shape manikins were iteratively positioned inside the CAD geometry. The resultant LTA-to-body contact and overlap were quantified, from which twenty-four test subjects whose predicted fit is at a borderline level were selected for physical fit testing. Using a 3D printed LTA mockup, the selected subjects were assessed for don/doff capability, and performed basic functional movements, including walking, kneeling and squatting. 3D scans were recorded, and a survey was administered for the subjective perception of fit and any discomfort locations. A statistical classifier based on a logistic regression model was developed using the obtained data and projected to a large database of approximately 1,800 body shapes from the US Army. The model estimated the overall proportion of the accommodated population to characterize the anthropometry of the crew who would fit in the LTA. The outcome determined if the current LTA sizing is adequate to meet the xEMU requirements.

Article: xEMU Lower Torso Assembly (LTA) Brief Fleet Sizing Study.

Authors: Kristine Davis, Richard Rhodes, K. Han Kim, Elizabeth Benson, Yaritza Hernandez, Linh Vu, Sudhakar Rajulu, NASA Johnson Space Center, Houston, TX, USA.