The proposed innovation is the development of a cathode feed electrolysis cell stack capable of generating 3600 psia oxygen at a relevant scale for future exploration missions. This innovation is relevant to NASA's need for compact, quiet, efficient, and long-lived sources of pressurized oxygen for atmosphere revitalization (AR) and EVA oxygen storage recharge. Present AR equipment aboard International Space Station (ISS) consists of power-intensive, noisy compressors that have service lives less than 2 years. Proton's proposed electrolyzer stack will eliminate the need for these compressors, by developing a cell stack that can produce 3600 psia oxygen via electrochemical compression. This innovation results in a quiet, efficient solid state device with no internal moving parts to service or fail.