Electrochemically Regenerable Metabolic CO ₂ and Moisture Control System for an Advanced EMU Application

Regenerable carbon dioxide (CO₂) and moisture removal techniques that reduce expendables and logistics requirements are needed to sustain people undertaking extravehicular activities for the Space Station. Life Systems, working with National Aeronautics and Space Administration has been developing and investigating the ways to advance the Electrochemically Regenerable CO₂ and Moisture Absorption (ERCA) technology to replace the nonregenerable solid lithium hydroxide absorber for the advanced Portable Life Support System (PLSS).

During extravehicular activities the ERCA technique uses a mechanism involving gas diffusion and absorption into liquid absorbent for the removal and storage of the metabolically produced CO₂ and moisture. Following the extravehicular activities, the expended absorbent is regenerated on-board the Space Station by an electrochemical method which restores the CO₂ and moisture absorption capabilities of the absorbent. Trace contaminants generated during extravehicular activities can also be removed by impregnated active carbon.

The ERCA technology, due to its use of liquid absorbent, has the ability to effectively satisfy the high metabolic CO₂ and moisture removal requirements of PLSS applications. This paper defines the ERCA technology concept and its advantages for the PLSS application, reviews breadboard and subscale test data and presents the results of design concepts for a prototype Absorber Module of improved performance and the physical characteristics of the projected flight hardware.