Last month, an unpiloted X-61 Gremlin drone was successfully retrieved by a specially modified-Lockheed C-130 cargo plane while both were still flying. The achievement, which you can see a video released last Friday by DARPA (the Defence Advanced Research Projects Agency), promises to dramatically increase the operating range of these types of aircraft.
The advent of mid-air refuelling, which was first demonstrated using hardware similar to modern air-to-air refuelling techniques as far back as 1935, changed warfare. The range of fighter planes, which are designed to be fast and nimble and burn through fuel like it’s going out of style, was suddenly no longer operationally limited by how far a plane could fly on a full tank of gas. They could participate in much longer missions, and intercept targets farther away by simply joining up with a tanker plane mid-flight and refilling without finding a safe place to land first. The Lockheed SR-71 Blackbird spy plane was completely dependent on mid-air refuelling, as its fuel system would bleed on the runway until the aircraft took flight and the fuselage warmed up and expanded, sealing every gasket tight.
Mid-air refuelling can help a plane stay aloft for forever, but there are two factors that force fighter jets to eventually land: pilot fatigue and maintenance needs. You can’t repair an engine while it’s sucking air like the world’s most aggressive vacuum, and all humans eventually need food and sleep. We’ve all but solved the human pilot problem through the use of drones that either fly completely autonomously, carrying out pre-programmed missions based on GPS and other data, or are controlled by pilots safely located thousands of miles away sitting in what look like the ultimate video game flight simulator.
The maintenance problem is a lot harder, but it looks like the U.S. military has taken a big step toward solving it. The goal of the Gremlins program is to use a larger aircraft, like a cargo plane, to deliver a drone as close as possible to a region where it’s not safe for human pilots to operate. The drone can be launched in mid-air, perform its mission, and then return to safe airspace where the cargo plane can grab it and carry it the rest of the way back to a military base or other airport where it could be refurbished and prepped for the next mission in less than 24 hours.
Tests conducted last December were a failure, with three drones having to make emergency parachute landings, but last month, at the Dugway Proving Ground in Utah, a C-130 was able to successfully recover one of two X-61 Gremlin drones in mid-air (the second unfortunately didn’t make it). The test proves the approach is feasible, and while the process in no way looks easy, as more and more successful captures are completed, the techniques will be further improved until one day capturing a drone in mid-flight is as common a practice as mid-air refuelling.
The accomplishment raises another possibility. Immediately popping off the engine covers of a drone that’s been flying for hours and dismantling its components for inspections isn’t advisable. But one day, in addition to topping off fuel tanks, drones like these could even possibly be repaired and made ready for the next mission inside the belly of a cargo plane, without either aircraft actually having to land first.