Spacesuit Thermal Control System Requirements for Martian Surface Operations Using Analytical Modeling

As humans look toward exploring planetary bodies, the limitations of current spacesuit thermal systems may pose operational challenges. Thus, current thermal systems may not meet the needs of this new exploration paradigm. Passive cooling may address spacesuit- and mission-specific challenges by allowing heat exchange between the astronaut and the environment, potentially resulting in a decrease in thermal system complexity, consumables, and mass. Analytical models have utility in understanding the design envelope of a complex system and have been used in prior work to analyze human thermal states in alternative spacesuit architectures, lunar environmental conditions, and metabolic profile ranges. While providing initial results on differences in spacesuit thermal performance, these research efforts did not incorporate sex or body segmentation, which have both been shown to have effects on thermal comfort. The analytical thermal model presented in this paper builds on past research by incorporating gender and specifying body region, increasing the model fidelity, and allowing for additional alternative spacesuit architectures to be modeled. The results have utility in understanding the bounds of a system and resulting design requirements that can feed into higher-fidelity computational models for detailed system design to be tailored to operational, environmental, and gender-specific considerations.