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More UAVs Taking Off

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Two highly significant contracts that were awarded by the Department of Defense last week will have great impact on the rapidly increasing role of Unmanned Aerial Vehicles (UAVs) in the U.S. armed forces. The first, on 21 April, was for phase one of the Vulture program intended to provide an unmanned aircraft with an endurance of five years. The second contract, announced a day later, was to acquire the RQ-4N variant of the Global Hawk for the Navy's Broad Area Maritime Surveillance (BAMS) program.

The Vulture program -- under the aegis of the Defense Advanced Research Projects Agency (DARPA) -- envisions a vehicle carrying a 1,000-pound payload drawing five kilowatts of power that is able to remain aloft for an uninterrupted period of at least five years while remaining in the required mission airspace 99 percent of the time.

The Vulture phase one contracts were awarded to Aurora Flight Sciences, Boeing, and Lockheed Martin. According to DARPA, the Vulture program will focus on developing innovative technologies and approaches for in-flight energy collection (e.g., from solar panels) or refueling in flight and ultra-reliable systems or systems that could be repaired in flight. Other technologies that will be developed include multi-junction photovoltaic cells, high specific energy fuel cells, extremely efficient propulsion systems, advanced structural designs.

In the second phase of Vulture the contractors will refine demonstrator designs, continue technology development, and conduct an uninterrupted three-month flight of a sub-scale demonstrator. Phase three will consist of a continuous 12-month flight of a full-scale demonstrator.

In some respects the Vulture will be a corollary to the Helios UAV program. That vehicle was a long, thin, flying wing intended to fly higher than any unmanned aircraft ever. It passed an altitude of 76,000 feet on its first solar-powered test flight on 14 July 2001. Operating from the Pacific Missile Range Facility on the island of Kauai, Hawaii, no problems were encountered during the 10-hour, 17-minute flight. A flight the following 13 August took the UAV to 96,863 feet.

The Helios crashed two years later. A 247-foot-long flying wing that measured only eight feet front to back, Helios was a $15 million aircraft controlled from the ground by pilots using desktop computers. Its 14 propellers were driven by small electric motors powered by solar cells built into the wing. Helios was built by a partnership of the National Aeronautics and Space Administration and AeroVironment Inc. of Monrovia, California.

While the Venture's primary goal will be endurance rather than altitude, it will also be a high-flyer, able to provide unprecedented surveillance and other functions over a designated area.

In a less prosaic UAV effort, a year after proposals were received, the Navy has selected Northrop Grumman's Global Hawk for the BAMS program. The $1.16 billion cost-plus-award-fee contract will develop the RQ-4N variant for persistent maritime Intelligence, Surveillance, and Reconnaissance (ISR) data collection and dissemination.

The Global Hawk is the largest operational UAV ever produced, having a 116-ffot wingspan, a length of 44 feet, and weighing almost 26,000 pounds with a 2,000-pound internal payload. The UAV first flew in February 1998 and soon entered U.S. Air Force service. It continues in production.

In U.S. Navy service the RQ-4N variant will compliment the new P-8A Multi-Mission Maritime Aircraft (MMMA), which is planned to replace the long-serving Lockheed P-3 Orion. The BAMS/RQ-4N platform may be particularly useful in some of the electronic intelligence missions flown by the EP-3E aircraft as well as various one-of-a-kind Orion environmental and oceanographic research missions.

And, looking to the long term, the BAMS/RQ-4N, with its current endurance of almost 24 hours and large payload, may eventually perform other missions in direct support of the fleet, such as Airborne Early Warning (AEW).

These two UAV efforts -- the long-term Vulture and the near-term BAMS -- are further indications of the increasing significance of unmanned vehicles to U.S. military operations.

-- Norman Polmar

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