DARPA's goal to develop a UAV that can launch from small-deck ships in the US Navy and Marine Corps fleets, for intelligence, surveillance and reconnaissance, as well as targeting and strike missions, is a step closer to getting off the ground, according to Northrop Grumman's latest progress report on the Tern program. The company has announced that the Tern unmanned aerial vehicle (UAV) has passed two critical design reviews (CDRs), putting it on track for a full demonstration in 2018.

The Tern program is being conducted by DARPA and the US Navy's Office of Naval Research (ONR). To make use of limited space on a ship without a full runway on deck, the Tern takes off vertically from a tail-sitting position before leveling out in the air and transitioning to horizontal flight. With a range of more than 600 nautical miles (690 mi, 1,111 km) the aircraft is designed to carry payloads of over 1,000 lb (454 kg) and would support large ship-based, long-range, long-endurance unmanned air systems.

After being awarded Phase 3 of the program last December, Northrop Grumman has announced that the Tern cleared a couple of CDRs in October this year. The first test greenlit the aircraft's General Electric engine configuration, which allows it to fly both vertically and horizontally. Then, the second CDR approved of the hardware and software architecture of its vehicle management system, which grants the Tern the ability to take off vertically, transition to horizontal flight for increased efficiency and range, before transitioning back to vertical flight again for landing.

"Tern's unique combination of speed, long endurance, range, and altitude would give the Navy and Marine Corps a cost-effective, transformational capability to conduct ISR, light strike, and other missions from the sea at ranges exceeding 600 nautical miles," says Bob August, the Tern program manager. "These successful milestones add confidence to our plan to demonstrate this new vehicle capability in 2018."

By the end of Phase 3, Northrop Grumman will have designed and developed two full-scale prototypes of the Tern, conducted land-based tests and eventually demonstrations at sea.

The company discusses the concept in the video below.