Consideration of Open Loop Regenerable Carbon Dioxide and Humidity Removal Systems for Lunar Habitats

As NASA moves towards the development of life support systems for Lunar Habitats, there has been a renewed interest in open-loop regenerable carbon dioxide (CO2) and humidity removal systems. These systems would eliminate the need for the resupply of consumables associated with non-regenerable lithium hydroxide-based (LiOH) CO2 removal systems. This paper reviews flight-proven open-loop regenerable and non-regenerable CO2 and humidity removal systems as well as emerging high maturity systems. A new trade study between a LiOH-based system and a Sorbent-Based Atmosphere Revitalization (SBAR) system for the initial Surface Habitat (SH) application is presented. Suitability for the specific SH mission characteristics, which includes long dormancy periods at low temperatures, is also considered.