Spies in the sky: surveillance needs fuel demand for unmanned vehicles.

• Position: UNMANNED VEHICLES

Military commanders increasingly are relying on unmanned aircraft for surveillance and reconnaissance, especially in maritime areas, noted a new Defense Department report.

This trend, officials said, is indicative of a steady rise in the use of robotic vehicles in military operations.

Currently, there are nearly 1,000 robotic vehicles in the Central Command theater of operations. "The combatant commanders like them. They keep asking for more," said Dyke Weatherington, deputy undersecretary of defense for acquisition, technology and logistics.

Weatherington is in charge of the defense secretary's planning task force for UAVs, which the Pentagon has renamed "unmanned aerial systems," or UASs. "The vehicle, while important, is only one element in a complex system," he told a recent industry conference that was hosted by the Navy International Office.

In August, the task force issued a 213-page UAS roadmap that outlined the Pentagon's plans for the evolution of military unmanned aerial technology during the next quarter century.

A priority for combatant commanders is "persistent ISR [intelligence, surveillance and reconnaissance, an uninterrupted flow of information over extended periods of time], especially in maritime areas," he said. "UASs are suited to those roles."

The Navy and the Coast Guard, particularly, need more help patrolling the long U.S. coastline, the Persian Gulf and other sea-lanes, Weatherington said.

As a result, he explained, the defense secretary's office "is working with the Navy to rapidly accelerate fielding of UAS capabilities to the fleet."

This summer, for example, the Navy began flight tests at Patuxent River Naval Air Station, Md., with two RQ-4A Global Hawk UAVs as part of a demonstration program to help determine what capabilities an unmanned aircraft would need to patrol U.S. coastlines and the open ocean. The unmanned aircraft would supplement the Navy's manned P-3C Orion maritime surveillance aircraft and its planned replacement, the Maritime Multi-Mission Aircraft.

The Global Hawk made by Northrop Grumman Integrated Systems of El Segundo, Calif.--is a long-range unmanned aircraft with a range of 12,000 nautical miles. It has a wingspan of 116 feet and a length of 44 feet.

The Air Force has employed the Global Hawk in more than 60 combat missions. Flying at heights up to 65,000 feet with speeds approaching 400 miles per hour for as long as 35 hours, the Global hawk has put in more than 4,300 combat hours in 200 missions since 2001, according to Northrop Grumman spokesman Rovelle Anderson.

Since the invasion of Afghanistan, the...