Abstract: Background: Carbon Dioxide removal is a key aspect of Life Support for long-duration missions – Need to improve Mass, Power, and Volume of systems; Cabin air has three major constituents – Oxygen and Nitrogen, Carbon dioxide (CO2), Water Vapor; The mechanism for strong CO2 adsorption in zeolites (and many sorbents) is also the same mechanism for H2O – Water vapor is selectively adsorbed over CO2.