Enhanced Simulation of Partial Gravity for Extravehicular Activity

Prior studies of human locomotion under simulated partial gravity have hypothesized that energy expenditure is increased in lunar gravity, as compared to that of Mars. This may be due to subjects having to expend excess energy for stability and posture control in the lower gravitational field. The physiological cause of this suspected ‘‘wasted energy’’ during locomotion in low gravity remains to be determined. This paper outlines factors to be considered for these analyses and enhancements to the simulation method that will enable assessment of inertial stability and associated metabolic cost. A novel simulation technique is proposed for assessing the effects of inertial rotation and variable mass on stability, metabolic cost, and biomechanics using a modified weight relief harness to simulate partial