Abstract: A method for producing oxygen and methane from carbon dioxide, and hydrogen utilizing a methanation reactor, a reforming reactor, and an electrolyzer. Carbon dioxide and hydrogen are reacted to produce methane and water. A portion of the water along with a portion or all of the methane is directed to a reforming reactor where it is reacted to produce hydrogen and carbon monoxide, while the remaining portion of the methane is stored. The hydrogen is recycled to the methanation reactor while the carbon monoxide is vented or stored for use as a fuel. The second portion of the water is electrolyzed to its constituents, hydrogen and oxygen. The oxygen is stored or used for life support while the hydrogen is recycled to react with additional carbon dioxide.