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The neutral body posture (NBP) has been characteristically observed from crewmembers in a 0 g space flight. This study quantified the NBP from International Space Station crewmembers using a new technique for structured camera calibration and multiple-camera 3D triangulation. Template manikins derived from 3D body scans of the individual subjects also were used to improve accuracy. A skeletal link system was embedded in the manikin and articulated to reproduce the posture matching with the calibrated video images. The estimated body shapes and postures were compared against the NASA Technical Standards. The NBP, as more reliably estimated from this study, can help to improve spaceflight hardware and spacesuit design.

During a Shuttle flight in the early part of 1999, one of the crewmembers was unable to operate the backrest lever for the light-weight seat in microgravity. It is essential that the crewmembers are able to adjust this back-rest lever, which is titled forward 2 degrees from vertical during launch and then moved backwards to 10 degrees aft of vertical upon reaching orbit. This adjustment is needed to cushion the crewmembers during an inadvertent crash landing situation. The original Shuttle seats, which had seat controls located on the front left and right sides of the seat, were replaced recently with the new light-weight seats. The controls for these new, seats were moved to the night side with one control at the front and the other at the back. While it was uncertain whether the problem encountered was unique to that crewmember or not it was clear to the personnel responsible for maintaining the Shuttle seats that not knowing the cause of the problem posed a safety concern for NASA. Hence the Anthropometry and Biomechanics Facility (ABF) of the Johnson Space Center was requested to perform an evaluation of the seat controls and provide NASA with appropriate recommendations on whether the seat lever positions and operations should be modified. The ABF designed an experiment to investigate the amount of pull force exerted by subjects, wearing an unpressurized or pressurized crew launch escape suit, when controls were placed in the front and back (on the right side) of the light-weight seat. Single-axis load cells were attached to the seat levers, which measured the maximum static pull forces that were exerted by the subjects. Twelve subjects, six male and six female, participated in this study. Each subject was asked to perform the pull test at least three times for each combination of lever position and suit pressure conditions. The results from this study showed that as a whole (or in general), the subjects were able to pull on the lever at the back position with only about half the amount of force that they were able to exert on the lever at the front position. In addition, the results also showed that subjects wearing the pressurized suit were unable to reach the seat lever when it was located at the back. Furthermore, the pull forces on the front lever diminished about 50 % when subjects wore the pressurized suits. Based on these results from this study, it was recommended to NASA that the levers should not be located in the back position. In addition, further investigation is needed on whether the levers at the front of the seat could be modified or adjusted to increase the leverage for crew members wearing pressurized launch/escape suits.

One of the reasons for reduction in performance when gloves are donned is the lack of tactile sensitivity. It was argued that grasping force for a weight to be grasped will be a function of the weight to be lifted and the hand conditions. It was further reasoned that the differences in grasping force for various hand conditions will be a correlate of the tactile sensitivity of the corresponding hand conditions. The objective of this experiment, therefore, was to determine the effects of glove type, pressure, and weight of load on the initial grasping force and stable grasping force. It was hypothesized that when a person grasps an object, he/she grasps very firmly initially and then releases the grasp slightly after realizing what force is needed to maintain a steady grasp. This would seem to be particularly true when a person is wearing a glove and has lost some tactile sensitivity and force feedback during the grasp. Therefore, the ratio of initial force and stable force and the stable force itself would represent the amount of tactile adjustment that is made when picking up an object, and this adjustment should vary with the use of gloves. A dynamometer was fabricated to measure the grasping force; the tests were performed inside a glove box. Four female and four male subjects participated in the study, which measured the effects of four variables: load effect, gender effect, glove type, and pressure variance. The only significant effects on the peak and stable force were caused by gender and the weight of the load lifted. Neither gloves nor pressure altered these forces when compared to a bare-handed condition, as was suspected before the test. It is possible that gloves facilitate in holding due to coefficient of friction while they deter in peak grasp strength.

One of the purposes of NASA's Shuttle missions is to deploy and retrieve satellites. Some of these missions require extravehicular activities (EVAs). During EVAs, crew members wear pressurized suits for protection from hazardous conditions and use a Remote Manipulator System (RMS) to transfer heavy objects from one location to another. Prior to the Hubble Space Telescope repair mission (STS-61), concerns were raised whether crew members would be able to hold onto the modules if the RMS started or stopped unexpectedly. An experiment was conducted to measure the handle forces during such a scenario and to determine whether these forces and moments were well within the capabilities of the crew. Four subjects participated in the study. Mockups were built to represent the characteristics of the actual unit and tests were conducted at the Precision Air Bearing Facility (PABF) which simulates a nearly friction-free environment. Force plates were attached to the mockups to monitor forces and moments during the test. Controlled translation and rotation tasks were also conducted to compare the results with those of sudden RMS run start/stop tasks. The results from this study showed that the forces and moments exerted by subjects during sudden stopping and starting conditions were well within the capabilities of the crew members. This study thus provided quantitative data for NASA to be assured of a safe and successful mission.