A promising method to extract oxygen from CO2, which constitutes more than 95% of the Mars atmosphere, is by using glow-discharge dissociation of CO2 combined with the permeation of the generated oxygen through a Ag membrane. Quadrupole mass spectrometry was utilized to measure the oxygen flux through a 0.35-mm-thick, 2.01 cm(2) area membrane separating a two-chamber system. On the upstream side of the membrane, a de glow discharge was established with 350 V and 5 mA current. It was found that as much as 75% of the CO2 was dissociated to form CO and O (part of which recombined to form O-2) The atomic and molecular oxygen generated were adsorbed on the membrane surface, subsequently dissolved into the Ag, and diffused through the membrane thickness to the downstream surface where it desorbed as molecular oxygen. The resulting oxygen flux was studied as a function of upstream CO2 pressure, discharge current, discharge probe to membrane distance, and membrane temperature. It was found that the atomic oxygen generated a much higher concentration gradient across the membrane than did the molecular oxygen which resulted in a correspondingly higher oxygen flux through the membrane. The total oxygen flux through the membrane with a CO2 glow-discharge pressure of 5 Torr and a membrane temperature of 450 degrees C was found to be greater than 10(14) cm(-2) s(-1). This method can be used to continuously and efficiently supply oxygen for astronauts in a future manned mission to Mars.