LOCKHEED MARTIN and Boeing have unveiled their DarkStar low-observable unmanned air vehicle (UAV) contender for the US Department of Defense's Tier III Minus programme.

The slim-line plan-form is optimised for a low radar-cross-section while providing aerodynamic efficiency. The 21m-span UAV is designed to be operated well above 45,000ft (13,700m) on reconnaissance missions of 8h or longer.

Power is provided by a single 8.5kN (1,900lb)-thrust Williams-Rolls-Royce F129 (FJ44) turbofan, which is buried in the saucer section made by Lockheed Martin.

The main body houses sensors designed to capture 5,480km2/h (2,100miles2/h) at 1m resolution, and which can perform 0.3m spot imaging.

Wide-area surveillance will be accomplished by a Westinghouse synthetic-aperture radar (SAR) based on the APQ-183 mutli-mode radar developed for the cancelled General Dynamics A-12, or by an electro-optical (EO) sensor developed by Recon/Optical of Illinois. The SAR and EO mission payloads will be interchangeable in the field.

Loral is supplying two airborne datalink modems for the DarkStar: a lightweight version of the Line-of-Sight (LOS) common-datalink (CDL) airborne modem, which gives direct wide-band air-to-ground CDL, and a modified version of the satellite communications (Satcom) modem developed for the Predator programme.

The UAV will be capable of autonomous take off, cruise, landing and roll out and can be reprogrammed in flight for air-traffic or mission-requirement reasons. "It has several levels of autonomous capability, depending on the survivability of the situation," says Boeing Defense and Space group programme manager Richard Alldredge. "It will decide by itself whether to carry on in the area, loiter or return quickly to base."

The all-composite, all-bonded, high-aspect-ratio wings, made by Boeing, borrow from the Condor and Compass Cope UAV programmes in design and manufacture.

The plan-form of the high-laminar-flow wing was altered slightly mid-way through the 11-month programme to correct airflow problems caused by the angle of incidence between the wing and the body. "We froze the configuration early on [11 days into the $124 million programme] and, as a consequence, didn't have chance to take this configuration into the wind tunnel. So we put an insert into the root of the wing which increased the span," says Alldredge. "A definitive aircraft will be different," he adds.

At the core of the flight-control system is a Honeywell-supplied BG1232 integrated flight-management unit, HG1700 inertial-measurement unit and H-764 embedded global-positioning and inertial-navigation systems.

The UAV will be moved to nearby NASA Dryden at Edwards AFB, California, in late July in preparation for the first flight, which is due to begin later this year.

Source: Flight International