A cooling system in which an ACS (air cycle system) turbine may be driven by high pressure air from a turbo-fan engine and a VCS (vapor cycle system) having an evaporator and a VCS refrigerant compressor may be driven by the ACS turbine. Fluid of the chilled fluid reservoir, which may be chilled fuel, may be circulated through and cooled in the evaporator. In some embodiments, the ACS turbine may be coupled to the VCS refrigerant compressor by a magnetic coupling.