An innovative Microchannel Sabatier Reactor System (MSRS) is proposed for 100% recovery of oxygen (as water) and methane from carbon dioxide (CO2), a valuable in situ resource available in the atmosphere or as frozen deposits on Mars and other Near Earth Objects (NEOs), using hydrogen. The Sabatier reaction will greatly benefit from inherently superior microreactor heat and mass transfer characteristics compared to conventional reactor designs. Significantly, multiple microreactors can readily be configured in series or parallel arrangements that improve reaction outcomes, and process scale up is easily achieved by numbering up mass produced microreactors. High conversion rates will require the deposition of highly active, supported catalyst layers onto microchannel walls that enhance surface area, adsorption characteristics, and catalyst effectiveness factor. Another research focus area will be a MSRS design that optimizes residence time, thermal recovery, and the achievement of equilibrium at low temperature. Successful completion of the Phase I project will provide microreactor performance data required to design and assemble a first generation MSRS. The Phase II research will result in the development of a prototype MSRS incorporating integrated sequential microreactors and heat exchange with the capability of processing 1 kg hr-1 of CO2. The prototype MSRS will clearly demonstrate the efficacy of this in situ resource utilization approach.