Gremlins UAV Demonstrates First Mid-Air Recovery

 - November 8, 2021, 5:19 AM
An X-61A successfully engages the "bullet" capture device. Once engaged, the air vehicle is winched up into the trapeze before being lifted back aboard the Hercules carrier by the docking arm. (Photo: DARPA)

During an October 29 trial at the Dugway Proving Ground in Utah, a Lockheed C-130A Hercules aircraft launched and recovered an X-61A Gremlins Air Vehicle (GAV) in flight for the first time. The feat is an important milestone for the U.S. Defense Advanced Research Projects Agency (DARPA) Gremlins program, which is exploring the concept of using large aircraft as launch platforms for recoverable swarming unmanned air vehicles.

The test involved the C-130 launching two X-61As, of which one was recovered using the “bullet” stabilized capture device towed behind the Hercules. A second GAV was destroyed during the tests. However, the recovered air vehicle was refurbished and flown again in less than 24 working hours.

“This recovery was the culmination of years of hard work and demonstrates the feasibility of safe, reliable airborne recovery,” said Lt. Col. Paul Calhoun, Gremlins program manager with DARPA’s Tactical Technology Office. “Such a capability will likely prove to be critical for future distributed air operations. Airborne recovery is complex. We will take some time to enjoy the success of this deployment, then get back to work further analyzing the data and determining next steps for the Gremlins technology.”

The Gremlins program got under way in 2016, with the aim of studying the use of swarming UAVs for release and recovery by  a range of aircraft, including large tactical and transport types. Operational air vehicles are intended to carry a variety of payloads, including reconnaissance sensors and electronic warfare systems, to aid manned aircraft during missions. Recovering the low-cost vehicles in mid-air allows them to be re-used, with a target life-span of around 20 missions for each.

Dynetics, a Leidos subsidiary, was selected in April 2018 ahead of General Atomics to provide the X-61A GAV for the Phase 3 flight demonstrations, with the initial five vehicles being built by Kratos. The first was flown in November 2019. Mid-air recovery attempts were not initially undertaken, the GAVs deploying a chute-based recovery system following flight trials aimed at testing the vehicle’s autonomous operation and swarming capabilities, although this system failed on the first flight, leading to the destruction of the GAV.

In October 2020 DARPA undertook a test campaign during which nine attempts were made to recover GAVs in flight. None of the attempts was successful but all—according to the agency—were “inches from success.” The tests produced sufficient data to provide a better understanding of the aerodynamic interaction between the GAV and the recovery device. DARPA’s aim for the Gremlins program is to successfully demonstrate the recovery of four GAVs in 30 minutes.