Carbon Dioxide Removal Technologies for Space Vehicles - Past, Present, and Future

As NASA looks forward to human missions to long term deep space missions and the technologies required for them, it is essential to look back at the technologies that have been used to date in Low Earth Orbit and short term lunar missions in order to derive insights and lessons learned. This paper will provide a history of CO2 removal systems and components used throughout the history of U.S. human space missions, including Mercury, Gemini, Apollo, Shuttle, and international Space Station (ISS) programs. A parametric comparison of the systems utilized will be included, along with on orbit maintenance requirements, failure mechanisms, and contamination sensitivity. Advantages and disadvantages as well as lessoned learned are identified. Special emphasis is given to the Carbon Dioxide Removal Assembly (CDRA), which with over 15 years of operation on ISS continues to provide valuable insights and lessons learned that can and must be applied to future systems in order to ensure success of the missions they will support. With this history and lessons learned established, candidate technologies for CO2 removal on future deep space missions are introduced.