A regenerable metal oxide CO2 absorber is being developed for future Extravehicular Mobility Unit (EMU) applications. It was designed to fit the existing shuttle EMU without modification of the interfaces.Absorption and regeneration tests were performed with subscale and full-size laboratory absorbers. Data is presented for open and closed loop absorber tests that evaluate the effects of residence time, mass velocity, and internal temperature on performance, with emphasis is on the full-size test unit. Regeneration testing quantified the effects of temperature and air flow rate on desorption rate, and of various absorber cooling modes. Its objective was to optimize conditions for minimum peak power and minimum total energy consumption.