Water Recovery for Regenerative Life Support Systems

Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Regenerative CO2 removal systems are attractive for these missions because they do not use consumable CO2 absorbers. However, these systems also absorb and vent water to space along with the carbon dioxide. We propose to develop an innovative water recovery system that minimizes water lost from regenerative CO2 control systems without the need for low-temperature condensing heat exchangers. This approach addresses the need for water recovery systems in long-duration missions, reduces the need for consumables by enabling use of state-of-the-art regenerative CO2 removal systems, and minimizes demands on the spacecraft thermal control system. In Phase I we proved the feasibility of our approach through proof-of-concept tests that demonstrated efficient water recovery from a compact exchanger with low pressure losses. Trade-off studies using our mass transfer analysis models have yielded a design for a full-size prototype that meets all the requirements for service on future spacecraft. In Phase II we will build the prototype and measure its performance in ground tests of a full-scale, regenerative CO2 removal system.