Investigation of Joint Torque Characteristics for a Mechanical Counter - Pressure Spacesuit

Mechanical counter-pressure (MCP) spacesuit designs have been a promising, but elusive alternative to historical and current gas pressurized spacesuit technology since the Apollo program. One of the important potential advantages of the approach is enhanced mobility as a result of reduced bulk and joint torques, but the literature provides essentially no quantitative joint torque data or quantitative analytical support. Decisions on the value of investment in MCP technology and on the direction of technology development are hampered by this lack of information since the perceived mobility advantages are an important factor. An experimental study of a simple mechanical counter-pressure suit (elbow) hinge joint has been performed to provide some test data and analytical background on this issue to support future evaluation of the technology potential and future development efforts.

Measurements of joint torque in a simple prototype MCP elbow joint demonstrated comparable performance at modest flexure angles to a mature gas pressurized elbow joint design at approximately the same applied pressure. These results suggest that reduced spacesuit joint torques may be achievable in an MCP design. Detailed test results and analyses suggest directions for design development to achieve reduced joint torques an increase applied pressure uniformity as the joint is flexed. Further research to explore these possibilities is recommended.