The permeation of oxygen through Ag normally occurs by a sequence of steps which include the initial dissociative adsorption of molecular oxygen at the upstream surface, the dissolution of the atoms into the bulk, and the subsequent migration of the atoms between octahedral sites of the lattice until they arrive at the vacuum interface downstream. The dissociative adsorption step, however, proceeds slowly, as indicated by the low sticking coefficient of O2on Ag(10−6–10−3). The application of a dc field in 0.5 Torr of O2(E/n∼10−14V cm2) on the upstream side of a Ag membrane generated gas phase atomic oxygen that substantially enhanced the transport. The transport flux was observed to increase from a value of 4.4×1013cm−2 s−1to a glow discharge value of 2.83×1014cm−2s−1at a membrane temperature of 650 °C. This suggests that the dissociative adsorption step limits the supply of oxygen atoms to the upstream side of the membrane. When the upstream O2was replaced by an equal pressure of CO2, only a small permeation signal was observed, but the application of the glow discharge substantially increased the transport flux from 3.25×1012cm−2s−1to 1.74×1014cm−2s−1. This method of separating O2from a CO2environment may be a possible mechanism for providing a supply of oxygen for astronauts in a manned mission to Mars.