Search Results

A preliminary assessment of the reach envelope and field of vision (FOV) for a subject wearing a Mark III space suit was requested for use in human-machine interface design of the Science Crew Operations and Utility Testbed (SCOUT) vehicle. The reach and view of two suited and unsuited subjects were evaluated while seated in the vehicle using 3-dimensional position data collected during a series of reaching motions. Data was interpolated and displayed in orthogonal views and cross-sections. Compared with unsuited conditions, medio-lateral reach was not strongly affected by the Mark III suit, whereas vertical and antero-posterior reach were inhibited by the suit. Lateral FOV was reduced by approximately 40° in the suit. The techniques used in this case study may prove useful in human-machine interface design by providing a new means of developing and displaying reach envelopes.

A study was conducted to evaluate the performance characteristics of hand strength measurement devices in both earth gravity and zero gravity. It was noted that both hand grip and pinch strengths increased by approximately 14% in zero gravity. We believe that an exposure to zero gravity will affect the co-contracting muscle activity. More specifically, we hypothesize that the zero gravity silences or shuts down the antagonistic or anti-gravity muscles. This in turn will result in greater joint strengths when agonist muscles are activated voluntarily. This could also expose a joint to overexertion or injury situations. In summary, there is a great need to understand how zero gravity affects the musculoskeletal system from a biomechanical perspective.

According to NASA, any person with physical characteristics that are between those of a 5th percentile Japanese female and a 95th percentile American male shall be eligible to become an astronaut. Because of this guideline, pathways and workspaces within a space vehicle must accommodate a wide range of population. Unfortunately, there is often a shortage of space inside the space vehicle. Hence, designers try to maximize the use of space. One way to accomplish this is by finding the minimum volumetric requirement that would ensure safety and comfort for the crewmembers. Until now, static, uni-variate anthropometric data were used to derive these guidelines. Our concern is that they may misrepresent the dynamic postural variations of the crew onboard the space vehicle. We used a posture based whole-body anthropometric approach to determine the variation in the three different clearances and updated the design guidelines accordingly.

The primary objectives of this study were to determine the factors that affect stability during locomotion in both lunar and martian gravity environments and to determine the criteria needed to enhance stability and traction. This study tested the effects of changing the speed of locomotion and the pattern of locomotion under three gravity conditions. The results showed that as the gravity level decreased, the amount of vertical and horizontal forces dropped significantly. The results also showed that there are some similarities across gravity levels with regard to changing the speed as well as the pattern of locomotion. In general, an increase in the speed resulted in an increase in the vertical and the horizontal forces. A change in the pattern of locomotion showed that even at reduced gravity, it will be more difficult to stop than compared to continue or start the motion.

The objective of this investigation was to measure and document the existence of any significant differences in physical performance under operational conditions between the Launch Entry Suit (LES) and the new Advanced Crew Escape Suit (ACES). The LES is a partial pressure suit currently worn by astronauts during the launch and entry phases of Shuttle missions. The ACES is a full pressure suit under consideration as a replacement for the LES. One prototype ACES has been fabricated and was used in this investigation. This report presents the results of three tests conducted with six subjects to allow a comparative evaluation of the two suits. The three tests included a reach envelope test, a strength test, and a treadmill test. The reach envelope test measured and compared the maximum hand displacements during horizontal and vertical reaches of both left and right arms in one-g conditions.