Joint Unmanned Combat Air Systems, or J-UCAS, was the name for the joint U.S. Navy and U.S. Air Force unmanned combat air vehicle procurement project. The two vehicles involved in the project were the Boeing X-45 and Northrop Grumman X-47. J-UCAS was managed by the Defense Advanced Research Projects Agency. In the 2006 Quadrennial Defense Review, it was stated that the J-UCAS program would be terminated and instead a new long-range strategic bomber program, "Next-Generation Bomber", for the Air Force has been launched. The program was revitalized into a Navy-only program named UCAS-D. History It is unusual for DARPA to be involved with advanced development programs; the agency normally performs proof-of-concept demonstrations and then hands follow-on programs on to interested military services. Apparently this arrangement was driven from the office of the secretary of defense, the idea being that DARPA would be able to keep the development effort on track until advanced demonstrators were available, and then the program would have so much momentum that it would keep on going. The long list of US military UAV programs that have been bungled and dropped after much expense and effort, with some of them like the Hunter ending up effectively reaching operational service in spite of it, provoked the decision. Of course, the candidates for the J-UCAS program included developments of the follow-ons to the Boeing X-45A and the Northrop Grumman X-47 Pegasus. DARPA and Boeing had been working on the "X-45B", a scaled-up X-45A that was seen as the prototype for an operational machine that would reach service in 2008, and would carry a 1,590 kilogram (3,500 pound) warload to a combat radius of 1,665 kilometers (900 nautical miles). Two were to be built, but before any metal could be bent for the two X-45B prototypes planned, the Air Force redirected the effort to an even more capable machine, the "X-45C". The X-45C, as currently envisioned, will be a flying wing powered by a single F404-GE-102D turbofan engine. Current specs include: The payload and range specifications are as defined by J-UCAS requirements. The operational radius specification is for a strike to a predefined target and back home again. A secondary range specification dictates a two-hour loiter capability at a radius of 1,850 kilometers (1,000 NMI). Partly because of the pressure from Boeing, in the summer of 2003, Northrop Grumman formed an alliance with Lockheed Martin to help develop the "X-47B",