Optimizing Portable Life Support System Sizing Given Crew Capabilities and In-Situ Recharging
Year: 2025
Type: conference-paper
Abstract: During the Apollo era portable life support systems (PLSS) for extravehicular activities (EVAs) were entirely self-contained in the suit backpack, and were comparable in mass to the wearer and the pressure garment. EVA durations were limited by the sizes of oxygen tank and the water reservoir for the sublimation cooling system, the battery energy storage, and the capacity of the lithium hydroxide (LiOH) canister to absorb carbon dioxide. Resupply of the PLSS involved a partial tear-down to replace batteries and LiOH canisters. For future lunar and Mars exploration, however, robotic systems should be ubiquitous, and advances in life support technologies should minimize or eliminate the need to replace modules between EVAs, allowing the potential for in-situ recharging via umbilical. In such a scenario, smaller PLSS units would be worn by EVA crew for independent surface traverses, with recharging taking place while riding on a rover from site to site. This study starts with an experimental investigation of human load-carrying capabilities under lunar and Mars gravity levels using underwater body segment parameter ballasting. Backpack weights are varied while the test subject walks at different speeds on an underwater treadmill. Data is obtained by subjective evaluations, as well as measured parameters such as speeds for walk-run transition and physiological workloads. In parallel, a design study will be performed on shorter-duration PLSS design, investigating the best architectures for specific life support hardware for shorter durations and to facilitate full system recharging via an umbilical connection. Estimates of required recharge times as a fraction of disconnected usage duration will identify required time on rover between independent surface sorties. Analogue testing with the UMd BioBot system will seek to identify desirable and minimum acceptable durations for independent surface activities, to bring this all together into a consistent framework for enhanced EVA operations.
Authors: Ryan Mahon, Meredith Embrey, Wyatt Bland, Avery Pierson, Matthew Frenia, Nicolas U. Bolatto, David L. Akin
Institution: University of Maryland, College Park
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7108330889
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