Airbreathing Combined Engines for Space Transportation Systems

For winged, horizontal take off and landing vehicule, the propulsion system appears as one of the key technologies. Based on the progresses in advanced technologies like cryogenic propulsion, high temperature materials, this paper will present progress on current concept studies of airbreathing/rocket combined engines with some consideratons on questions raised by the vehicule / engine system integration (air inlet / engine performances / aircraft trajectory and thrust requirements).