Further Testing of an Amine-Based Pressure-Swing System for Carbon Dioxide and Humidity Control

In a crewed spacecraft environment, atmospheric carbon dioxide (CO₂) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO₂ and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft, but additional data was needed on the operational characteristics of the package in a simulated spacecraft environment. One unit was tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the latter part of 2006. Those test results were reported in a 2007 ICES paper. A second test article, modified to use pressurized gas purge regeneration on the launch pad in addition to the standard vacuum regeneration in space, was incorporated for further testing in 2007. Metabolic rates and chamber volumes were also adjusted to reflect current program standards. Tests were run with a range of operating conditions: cycle time, vacuum pressure (or purge gas flow rate), air flow rate, and crew activity levels were all varied. Results of this additional testing are presented and potential flight operational strategies discussed.