A practical CO2 control system for ExtraVehicular Activity (EVA) on Mars have not yet been developed. TDA Research, Inc. proposes to develop a durable, high-capacity, continuously regenerable sorbent that can remove CO2 from the breathing loop. The energy for regeneration is provided by the metabolic load, and the sorbent can be regenerated at or above 6 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the breathing loop. In Phase I, we demonstrated the feasibility of the concept in a series of bench-scale experiments and by conducting a preliminary system analysis. We showed the sorbent regeneration can be accomplished with a temperature swing of only 17ºC, The entire system runs at near ambient temperature, and the sorbent can be regenerated at 13 torr (well above the Martian atmospheric pressure). We also performed over 1,000 adsorption/regeneration cycles to demonstrate the life of these sorbents. The major objective in Phase II is to design and fabricate a full-scale breadboard prototype unit to demonstrate the merits of the new technology. We will also improve the sorbent formulation.