Utilizing a Suited Manikin Test Apparatus and Space Suit Ventilation Loop to Evaluate Carbon Dioxide Washout

NASA is pursuing technology development of an Advanced Extravehicular Mobility Unit which is an integrated assembly made up of primarily a pressure garment system and a portable life support subsystem (PLSS). The PLSS is further composed of an oxygen loop, a ventilation loop, and a thermal loop. One of the key functions of the ventilation loop is to remove and control the carbon dioxide (CO2) delivered to the crew member. CO2 washout is the mechanism by which CO2 levels are controlled within the space suit helmet to limit the concentration of CO2 inhaled by the crew member. CO2 washout performance is a critical parameter needed to ensure proper and robust designs that are insensitive to human variabilities in a space suit. A suited manikin test apparatus (SMTA) was developed to augment testing of the PLSS ventilation loop to provide a lower cost and more controlled alternative to human testing while providing a one to one match with the suit and manikin geometry used in CO2 washout analytical models. The dynamics of the breathing gas helmet ventilation and astronaut breathing are also captured. The CO2 removal function is performed by the regenerative Rapid Cycle Amine within the PLSS ventilation loop, and its performance is evaluated within the integrated SMTA and Ventilation Test Loop system. This paper will provide a detailed description of the schematics, test configurations, and hardware components of this integrated system. Results and analysis of testing performed with this integrated system will be presented within this paper.