Northrop Grumman will work to demonstrate unmanned air vehicle to unmanned air vehicle refuelling with two RQ-4 Global Hawks under a $33 million deal with the US Defense Advanced Research Projects Agency.

The KQ-X programme will bring together Northrop, NASA and the US's National Oceanic and Atmospheric Administration to retrofit two high-altitude long-endurance aircraft for an entirely autonomous hose-and-drogue refuelling. The programme will also mark the first attempt to pilot Global Hawks in formation, says Northrop.

Because the Global Hawk can fly at altitudes up to 65,000ft (20,000m), refuelling will take place at a much higher altitude than has previously been demonstrated with manned aircraft. Most aircraft refuelling takes place around the 20,000-30,000ft range, depending on the platform.

Northrop Grumman Global Hawk
 © Northrop Grumman

Source: Flight International