A Supported Liquid Membrane System for Steady State CO2 Control in a Spacecraft Cabin



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49th International Conference on Environmental Systems


Reducing the allowable concentration of carbon dioxide (CO2) in spacecraft is a critical need for NASA. The system now used on the International Space Station (ISS) is the carbon dioxide removal assembly (CDRA). While it has performed well on the ISS, managers have concluded that using the device to reach the new ppCO2 limit of 2.0 mm Hg is not practical and a new method is needed.

In this project, Reaction Systems, Inc. and the University of Colorado are developing a new, membrane-based system to maintain ppCO2 at no higher than 2.0 mm Hg. The system utilizes the recent advances made in supported liquid membranes (SLMs) to achieve the high CO2 permeance and selectivity needed to make this approach practical. Performance data obtained with a Reaction Systems’ SLM was used to produce a conceptual system design that indicates an SLM system can maintain CO2 at 2.0 mm Hg and still meet size and power limits. A membrane system operates under steady-state conditions, and therefore pumps and heaters can be sized to operate at peak efficiencies, which maximizes lifetimes and minimize power requirements.

Although the conceptual design of the SLM-based system proposed here is very promising, some of the data used to generate the design were obtained under conditions somewhat different from those that would be encountered in an application. Thus, the objectives of this Phase I STTR project are to acquire performance data for these components under representative conditions and then perform a thorough system optimization study using state-of-the-art software to identify the most efficient operating conditions for all components. In this paper, we report the performance data obtained under representative conditions and present the design of an optimized system for CO2 control.


David Wickham, Reaction Systems Inc., USA
James Nabity, Aerospace Engineering Sciences, University of Colorado, USA
Jordann McCarty, Aerospace Engineering Sciences, University of Colorado, USA
Robert Aaron, Aerospace Engineering Sciences, University of Colorado, USA
ICES103: Thermal and Environmental Control of Exploration Vehicles and Habitats
The 49th International Conference on Environmental Systems was held in Boston, Massachusetts, USA on 07 July 2019 through 11 July 2019.


carbon dioxide (CO2), supported liquid membrane, steady-state, spacecraft, environmental control