To provide a new means using air liquefaction to supply a rocket oxidizer for placing a recyclable artificial satellite into a low earth orbit in relation to a field of aerospace crafts.

High-pressure air is extracted from the central part of a turbo fan 20 through an extraction valve 32, and fed to a heat exchanger 36 through a turbine 33. Compressed air flows from the heat exchanger 36 to a LOX generator/separator 38 through a turbine 35. The LOX generator/separator 38 expands the coming air, liquefies it, and separates it to LOX and LN2. The LOX and LN2 are primary chemical components of the air. The newly produced LOX flows to an oxidizer tank 42 for storing the LOX through a turbine 41 until it is used for starting a rocket engine of the spacecraft.