The Competitive Standing of State-of-the-Art PLSS Technologies Given Prospective EVA Cadence

The Apollo-era Life Support System (LSS) utilized carbon dioxide (CO2) scrubbing canisters that were mechanically passive, reliable, and mass efficient in the context of the lunar mission parameters. Since Apollo, CO2 scrubbing technologies have been developed in an attempt to expand EVA capability. This paper will discuss the future applicability of these State-of-the-Art Primary Life Support Subsystem (PLSS) CO2 scrubbing approaches given the prospective cadence of manned exploration supporting commercial Low Earth Orbit (LEO) destinations, Lunar campaigns, and Martian campaigns. One of the primary metrics investigated is launched system mass to these destinations, a proxy for the operational cost effectiveness of each approach. Despite large investitures over the past 50 years into novel spacesuit life support approaches, flight-proven alternatives remain uniquely competitive and cost-effective options for certain mission regimes. By understanding the scope of future manned exploration and EVAs, we can prepare the most robust and efficient technical solution to meet humanity’s actual EVA need.