Abstract: A unique cooling system for an aircraft is designed to provide extremely low temperature cooling airflow. The system includes an air source, a first system compressor and a second system compressor positioned in series for compressing and heating the air. A least one heat exchanger can be used to cool the air at predefined locations. A condenser for condensing water out of the air is positioned downstream of the second compressor. The water can be removed with a water separator and at least a portion of any remaining water in the form of liquid or vapor is removed from the air in a membrane dehydration device. The air is expanded in at least one system turbine to bring the air temperature to a subfreezing temperature. The subfreezing air is then used to cool electronic components and mechanical components within the aircraft.