Mars Exploration Portable Life Support System Schematic Study: Architecture Down-Selection

Previous NASA Portable Life Support System (PLSS) designs have been focused on assisting extravehicular activity (EVA) in low gravity, vacuum environments. Development of a Mars Exploration Portable Life Support System (MxPLSS) therefore requires modifications to the baseline PLSS design that accommodate the unique operational conditions characterizing EVAs on Mars. In our previous study presented at the International Conference on Environmental Systems (ICES) 2025, paper number ICES-2025-90, a blank sheet approach pinpointed technologies with the potential to satisfy each major function of the MxPLSS. A comprehensive list of equipment was compiled, combinations of technologies were evaluated and compared, and seven promising schematics were recommended. Out of that study came a newly developed PLSS sizing tool, the Guided Utility Sizer (GUS), which aided in the comparison and detailed assessment of proposed architectures. As a continuation of this effort, enhancements to the GUS tool were made with the goal of confirming the most feasible schematic to develop into a workable test stand. Broadening and refinement of the tool’s capabilities were carried out to allow for more sophisticated insight into technology impacts at the PLSS- and vehicle-level. With the help of an improved down-selection process, thousands of technology combinations were evaluated and compared in the upgraded tool, and higher-quality schematic recommendations were made. This paper summarizes the study approach, schematic selection process, and final assessment that culminated in recommendations for open loop, semi-open loop, and closed loop PLSS configurations optimized for nominal Martian environmental conditions at EVA durations of 2, 4, 6, and 8 hours.