Application of strength requirements to complex loading scenarios

Abstract

NASA’s endeavors in human spaceflight rely on extensive volumes of human-systems integration requirements to ensure mission success. These requirements protect space hardware accommodation for the full range of potential crewmembers, but cannot cover every possible action and contingency in detail. This study was undertaken in response to questions from various strength requirement users who were unclear how to apply idealized strength requirements that did not map well to the complex loading scenarios that crewmembers would encounter. Three of the most commonly occurring questions from stakeholders were selected to be investigated by human testing and human modeling. Preliminary findings indicate that deviation from nominal postures can affect compliance with strength requirements positively or negatively, depending on the nature of the deviation. Human modeling offers some avenues for quickly addressing requirement verification questions, but is limited by the fidelity of the model and environment.