 The team responsible for developing the propulsion system includes Lockheed Martin, Northrop Grumman, BAE Systems, Pratt & Whitney and Rolls-Royce, under the leadership of the United States Department of Defense Joint Strike Fighter Program Office.Paul Bevilaqua, Chief Engineer of Lockheed Martin Advanced Development Projects (Skunk Works), invented the lift fan propulsion system.The concept of a shaft-driven lift-fan dates back to the mid-1950s.