The Northrop Grumman X-47 Pegasus is a demonstration Unmanned Combat Aerial Vehicle. The X-47 began as part of DARPA's J-UCAS project, and is now part of the United States Navy's UCAS-D program to create a carrier-based unmanned aircraft. Unlike the Boeing X-45, Pegasus development was company-funded. The initial vehicle carries the designation X-47A; the follow-on naval version is designated X-47B. The proof-of-concept X-47A vehicle was built under contract by Burt Rutan's Scaled Composites at the Mojave Spaceport. The roll out ceremony at Mojave was in July 2001 and the first flight was successfully completed in February 2003. The program was terminated on January 13, 2006 as part of the US Military's Quadrennial Defense Review. History The US Navy did not commit to practical UCAV efforts until mid-2000, when the service awarded contracts of US$2 million each to Boeing and Northrop Grumman for a 15-month concept-exploration program. [ [www.defenselink.mil... "DARPA And Navy Select Naval UCAV Contractors"] , US DoD, 20 June 2000.] Design considerations for a naval UCAV included dealing with the corrosive salt-water environment, deck handling for launch and recovery, integration with command and control systems, and operation in a carrier's high electromagnetic interference environment. The Navy was also interested in using their UCAVs for reconnaissance missions, penetrating protected airspace to identify targets for the attack waves. The Navy went on to give Northrop Grumman a contract for a naval UCAV demonstrator with the designation of "X-47A Pegasus", in early 2001. The Pegasus demonstrator looks like a simple black arrowhead with no vertical tailplane. It has a leading edge sweep of 55 degrees and a trailing edge sweep of 35 degrees. The demonstrator has retractable tricycle landing gear, with a one-wheel nose gear and dual-wheel main gear, and has six control surfaces, including two elevons and four "inlaids". The inlaids are small flap structures mounted on the top and bottom of the wing forward of the wingtips. Pegasus is powered by a single Pratt & Whitney Canada JT15D-5C small high-bypass turbofan engine with 3,190 lbf (14.2 kN) thrust. This engine is currently in use with operational aircraft such as the Aermacchi S-211 trainer. The engine is mounted on the demonstrator's back, with the inlet on top behind the nose. The inlet duct has a serpentine diffuser to prevent radar reflections off the engine fan. However, to keep costs low, the engine exhaust is a simple cylindrical tailpipe, with no provisions for reducing radar or infrared signature.