The Defense Advanced Research Projects Agency (DARPA), in a joint effort with NASA Dryden Flight Research Center, performed the first-ever autonomous probe-and-drogue airborne refueling operation August 30, at Edwards Air Force Base, Calif. The demonstration was conducted with a NASA F/A-18 configured to operate as an unmanned test bed.
The Autonomous Airborne Refueling Demonstration (AARD) system used GPS-based relative navigation, coupled with an optical tracker, to provide the precise positioning required to put a refueling probe into the center of a 32-inch basket dangling in the air stream behind an airborne tanker. The tanker was equipped with a small relative navigation pallet, but production refueling equipment was not modified in any way. Pilots were on board the F/A-18 for safety purposes.
This means a lot to the concept of long-range UAVs. One day unmanned tankers could be refuelling unmanned strike aircraft.
Some have claimed that automated refueling was virtually impossible in the comments section on MO, but this experiment seems to indicate otherwise.
Here’s the whole press release: DARPA PERFORMS WORLD’S FIRST HANDS-OFF AUTONOMOUS AIR REFUELING ENGAGEMENT (PDF file)