To support manned lunar and Martian exploration, NASA/JSC and LESC are conducting an extensive evaluation of air revitalization subsystems. The major operations under study include regenerative CO2 removal and reduction; O2 and N2 production, storage, and distribution; humidity and temperature control; and trace contaminant control. This paper describes the ongoing analysis of air revitalization subsystems, including ASPEN PLUS™ modeling and breadboard test stand operation.A comprehensive analysis program based on a generalized block flow model is currently being developed to facilitate the evaluation of various processes and their interactions. Future plans for the development of this simulation will be discussed. ASPEN PLUS™ has been used to model a variety of the subsystems described above; application of this package in modeling CO2 removal and reduction will be discussed.Several life support test stands have been constructed to test new and existing technologies for their potential applicability in space. The goal is to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. This paper will report the test stand setup and results from experimental studies of air revitalization systems. The CO2 removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical CO2 concentration (EDC). Membrane-based CO2 removal and humidity control, catalytic reduction of CO2, and catalytic oxidation of trace contaminants are also under investigation.