Continued Development of Multi-Gas Microsensor Array for the Exploration Portable Life Support System

The Portable Life Support System (PLSS) of the Exploration Extravehicular Mobility Unit (xEMU) requires sensors capable of measuring the major constituents of the gas stream. These major constituents include oxygen, carbon dioxide, and water vapor. The sensors must operate across a wide range of flow and pressure conditions and introduce very low pressure drop in the ventilation loop. The sensors must operate with low power and occupy a small volume. This paper reports the fabrication and testing of a compact, low power, multi-parameter astronaut life support sensor (M-PALSS) prototypes. M-PALSS combines an array of lowpower chemical sensors for oxygen (O2), carbon dioxide (CO2), water (H2O) vapor, and pressure as well as sensors for potential trace contaminates of carbon monoxide (CO) and volatile organic compounds. NDIR and electrochemical CO2 sensors are included. M-PALSS includes custom electronics to control the sensors and is packaged in a custom housing that meets the volume and shape requirements for service in the PLSS. M-PALSS prototype hardware has been developed and tested at relevant conditions for PLSS operation.