Ikhana unmanned aerial vehicle (UAV). This aircraft, operated by NASA, is a modified version of the General Atomics Aeronautical Systems MQ-9 Predator B UAV. It was acquired by NASA in 2006, and operates as a long-endurance, high-altitude unmanned research aircraft. Here, engine run-up is being carried out at Edwards Air Force Base, California, USA, before a pre-dawn takeoff on the first test flight of the new automatic dependent surveillance-broadcast (ADS-B) aircraft tracking technology. Most of the aircraft operating in US airspace will be required to use this technology by 2020. Photographed on 15 March 2012.