In an in-air demonstration in 2007, DARPA teamed up with NASA to show that high-performance aircraft can easily perform automated refueling from conventional tankers.
The 2007 demonstration was not entirely automated, however: a pilot was on board to set conditions and monitor safety during autonomous refueling operations. Building upon this foundation, DARPA, by way of its Autonomous High-Altitude Refueling program, demonstrated for the first time the ability to safely conduct fully autonomous aerial refueling of unmanned air vehicles (UAVs) in challenging high-altitude flight conditions.
During the program’s final test flight, two modified RQ-4 Global Hawk aircraft flew in close formation—100 feet or less between refueling probe and receiver drogue—for the majority of a 2.5-hour engagement at 44,800 feet.
The successful test helped pave the way for future unmanned high-altitude long-endurance aircraft that can refuel in flight, expanding their mission capabilities and range.
