A Comparison of Methods for Assessing Space Suit Joint Ranges of Motion

Abstract

Abstract:Through the Advanced Exploration Systems Program, NASA is attempting to use the vast collection of space suit mobility data from 50 years worth of space suit testing to build predictive analysis tools to aid in early architecture decisions for future missions and exploration programs. However, the design engineers must first understand if and how data generated by different methodologies can be compared directly and used in an essentially interchangeable manner. To address this question, the isolated joint range of motion data from two different test series were compared. Both data sets were generated from participants wearing the Mark III Space Suit Technology Demonstrator (MK-III), Waist Entry I-suit (WEI), and minimal clothing. Additionally the two tests shared a common test subject that allowed for within subject comparisons of the methods that greatly reduced the number of variables in play. The tests varied in their methodologies: the Space Suit Comparative Technologies Evaluation used 2D photogrammetry to analyze isolated ranges of motion while the Constellation space suit benchmarking and requirements development used 3D motion capture to evaluate both isolated and functional joint ranges of motion. The isolated data from both test series were compared graphically, as percent differences, and by simple statistical analysis. The results indicated that while the methods generate results that are statistically the same (significance level p= 0.01), the differences are significant enough in the practical sense to make direct comparisons ill advised. The concluding recommendations propose direction for how to bridge the data gaps and address future mobility data collection to allow for backward compatibility.https://ntrs.nasa.gov/search

Body Pose Measurement System: System Validation and Range of Motion/Kinematic Analysis of Three Pressure Suits

“…Due to how the data was acquired, we are thus far unable to quantify this variation. In order to do so, the first step would be to acquire the range of motion data for a statistically significant number of test subjects, also, if we take in account the considerations made by Aitchison in, 15 in order to have a valid estimate, the same system (or type of system) would be necessary. In this case we would require two variants of the BPMS system, one worn by the test subject and the second installed on the outer garment of the pressure suit.…”

A Review on Human-Spacesuit System Mobility Measurement and Modeling

“…Table 1 lists some frequently adopted isolated joint motions. Please go to [4] for picture illustrations of these motions. Because functional motions are heavily dependently on the tasks to be carried out in space missions, they are not listed in such a table.…”

“…As far as the techniques used for measurement are concerned, there are three choices: manually measurement by anthropometrist; Photo Method used by JSC's space suit and human factors teams in 1999; 3D-MC Method used for 2009 Constellation Suit Requirements. For detailed explanations of the latter two techniques, please refer to [4]. Here we emphasize one phenomenon observed in several ROM measurements that fit was a key factor affecting suit mobility evaluations and joint mobility was sensitive to subject fit [5,6].…”

Conceptual Design of Spacesuit Hard Hip Joint

“…Around joint mobility, many kinds of spacesuit joint had been developed, including flat-pattern joint, bellow-type joint, and rotation-bearing joint. Now, there are many research achievements in motion analysis and test [13,14], computational methods [15,16], human factors [17,18], and joint development [19,20]. As far as joint design is concerned, there is relatively less research on the improvement of hard joint design for many years.…”