Lockheed Martin’s Skunk Works advanced development unit is building an unmanned vertical takeoff and landing (VTOL) air vehicle under a U.S. Defense Advanced Research Projects Agency (DARPA) program to demonstrate a cargo UAV capable of carrying interchangeable mission payloads. DARPA plans to fly the prototype next year.

In a posting on its website this month, DARPA said the so-called Aerial Reconfigurable Embedded System (ARES) program has entered its third and final phase, which involves designing and building the prototype. The air vehicle design calls for twin, tilting ducted fans to provide hovering and landing capabilities “with rapid conversion to high-speed cruise flight similar to small aircraft.” The flight module, as DARPA calls it, would deliver and retrieve several different types of detachable mission modules, each designed for specific missions such as cargo resupply, casualty extraction and intelligence, surveillance and reconaissance. The flight module would have a useful load of up to 3,000 pounds, more than 40 percent of the takeoff gross weight of the aircraft. Soldiers could direct the flight modules using apps on their mobile phones or tablets.

“ARES would make organic and versatile VTOL capability available to many more individual units,” said Ashish Bagai, DARPA program manager. “Our goal is to provide flexible, terrain-independent transportation that avoids ground-based threats, in turn supporting expedited, cost-effective operations and improving the likelihood of mission success.”

ARES is the new name for an effort started in 2009, originally called Transformer, to demonstrate a four-person “flyable/roadable” vehicle combining the advantages of a helicopter and a ground vehicle. The projects agency later changed the program’s scope to eliminate the “roadable” capability. It awarded Lockheed Martin’s industry team the Phase 3 contract in late 2012 to perform detail design work, leading to a critical design review last year, the company said. DARPA then exercised an option to build and fly the ARES prototype in 2015.

Lockheed Martin Skunk Works is the lead vehicle design and systems integration contractor for the program’s third phase. Piasecki Aircraft of Essington, Pa., is designing the flight module, including the design of the lift system drivetrain.