Development of a Low-Power CO2 Removal and Compression System for Closed-Loop Air Revitalization in Future Spacecraft

Continuous removal of carbon dioxide is one of the most critical processes in a spacecraft air revitalization system. Recovery of the waste carbon dioxide and its subsequent conversion to oxygen become essential for long-duration human space missions beyond Low-Earth orbit where re-supply of consumables such as oxygen is neither practical nor economical. The current CO₂ removal technology employed in the United States Operating Segment (USOS) of the International Space Station (ISS) operates in an open loop mode where the waste CO₂ is vented to space. A compressor is required to facilitate CO₂ recovery capabilities. The CO₂ removal process itself is one of the most energy-intensive processes in the life support system of the ISS due to the water vapor recovery method involved in the process. This paper discusses the design and development of a low-power CO₂ removal system that has capabilities to recover and compress the CO₂ for recycling oxygen. The system utilizes processors with no rapidly moving parts to improve the factors such as life, safety and reliability. Significant power savings is possible by incorporating a membrane dryer for water vapor recovery. Additional savings in power is achieved by thermally integrating the CO₂ removal and compression systems.