A gas-assisted liquid fuel oxygen reactor system, comprising: a CO 2 -assisted atomizer (115, 215) having an inlet (120, 220) adapted to receive a liquid fuel and an outlet (125, 225) adapted to spray atomized fuel and CO 2; an evaporation zone (105, 205) having an inlet adapted to receive the atomized liquid fuel and CO 2 and having an outer wall (130, 230) that is formed of a thermally conductive material such that the evaporation zone (105, 205) is adapted to heat the atomized fuel and CO 2 into a vaporized form; a reaction zone (145, 245) co-axially aligned with and in flow communication with the evaporation zone (105, 205), wherein the reaction zone (145, 245) is adapted to receive a flow of the vaporized fuel and CO 2 from the evaporation zone (105, 205); an ion transport membrane (150, 250) that is coaxially aligned with the evaporation zone (105, 205) and defines the reaction zone (145, 245); an air vessel (155, 255) defined by structure that is disposed about the ion transport membrane (150, 250) and defines a first space between an outer surface of the ion transport membrane and an inner surface of the air vessel structure, wherein the air vessel structure is formed of a thermally conductive material and the air vessel (155, 255) is for receiving an air stream that flows in a counter direction relative to a flow of the vaporized fuel and CO 2 in the reaction zone (145, 245); wherein the ion transport membrane (150, 250) is adapted to provide O 2 permeating from the air stream and transfer the O 2 into the reaction zone (145, 245) resulting in an O 2 -depleted air stream in the first space of the air vessel structure, and wherein the reaction zone (145, 245) is adapted to combust the vaporized fuel and CO 2 in the presence of O 2 to produce heat and create exhaust gases that are recirculated in the system; characterized in that it comprises: a heating vessel (160, 260) defined by a structure that is disposed about the air vessel structure and defines a second space between an outer surface of the air vessel structure and an inner surface of the heating vessel structure, wherein the heating vessel (160, 260) is for receiving a heated air and gaseous fuel stream such that heat is transferred from the air and gaseous fuel stream to the first space. a CO 2 -assisted atomizer (115, 215) having an inlet (120, 220) adapted to receive a liquid fuel and an outlet (125, 225) adapted to spray atomized fuel and CO 2; an evaporation zone (105, 205) having an inlet adapted to receive the atomized liquid fuel and CO 2 and having an outer wall (130, 230) that is formed of a thermally conductive material such that the evaporation zone (105, 205) is adapted to heat the atomized fuel and CO 2 into a vaporized form; a reaction zone (145, 245) co-axially aligned with and in flow communication with the evaporation zone (105, 205), wherein the reaction zone (145, 245) is adapted to receive a flow of the vaporized fuel and CO 2 from the evaporation zone (105, 205); an ion transport membrane (150, 250) that is coaxially aligned with the evaporation zone (105, 205) and defines the reaction zone (145, 245); an air vessel (155, 255) defined by structure that is disposed about the ion transport membrane (150, 250) and defines a first space between an outer surface of the ion transport membrane and an inner surface of the air vessel structure, wherein the air vessel structure is formed of a thermally conductive material and the air vessel (155, 255) is for receiving an air stream that flows in a counter direction relative to a flow of the vaporized fuel and CO 2 in the reaction zone (145, 245); wherein the ion transport membrane (150, 250) is adapted to provide O 2 permeating from the air stream and transfer the O 2 into the reaction zone (145, 245) resulting in an O 2 -depleted air stream in the first space of the air vessel structure, and wherein the reaction zone (145, 245) is adapted to combust the vaporized fuel and CO 2 in the presence of O 2 to produce heat and create exhaust gases that are recirculated in the system; characterized in that it comprises: a heating vessel (160, 260) defined by a structure that is disposed about the air vessel structure and defines a second space between an outer surface of the air vessel structure and an inner surface of the heating vessel structure, wherein the heating vessel (160, 260) is for receiving a heated air and gaseous fuel stream such that heat is transferred from the air and gaseous fuel stream to the first space.