The USA is eyeing the Global Hawk UAV as an intelligence platform to partner the U-2

Ramon Lopez/WASHINGTON DC

US MILITARY officials are to determine whether the US Air Force should supplement its small fleet of ageing Lockheed U-2 reconnaissance aircraft or give the Northrop Grumman RQ-4AGlobal Hawk unmanned air vehicle (UAV) a bigger intelligence-gathering role.

The ongoing debate within the US Department of Defense (DoD) and the USAF is also considering the role of space-based intelligence assets. It will determine how to proceed with the U-X, the proposed next-generation spycraft, and the so-called Sensor Craft, a revolutionary UAV.

Indeed, some observers believe that the discussions go beyond simply determining the future of US military intelligence, surveillance, and reconnaissance (ISR) capabilities. They say the path selected for next-generation ISR could set many of the assumptions for the coming debate on whether unmanned combat air vehicles should supplement or even replace manned tactical aircraft .

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Fuelling the U-2 versus unmanned systems debate is the success of the Global Hawk. Although barely out of the technology demonstration stage, the USAF is moving ahead aggressively with plans to use this high-altitude, long-endurance UAV to augment its U-2 manned aircraft fleet.

USAF officials recently asked Northrop Grumman Ryan Aeronautical Centre if it could accelerate the Global Hawk's development to avoid the need to restart the U-2 production line.

According to sources, the USAF is interested in an expedited engineering and manufacturing development effort while adding a signals intelligence (SIGINT)mission. The RQ-4A's current payload consists of synthetic aperture radar/moving target indicator, electro-optical and infrared sensors.

With development of the Global Hawk for reconnaissance expected to begin in September, Northrop Grumman told the USAF that a one-year EMD effort is feasible, as is giving the RQ-4A a SIGINT role. Production of up to 48vehicles is to begin in 2003. Northrop Grumman can produce up to 10 Global Hawks a year and hopes to supply at least 100 to the USAF.

The initial Block 5 Global Hawk would be followed by the Block 10 with greater payload capabilities. It is envisaged giving the UAV stealth features, making the RQ-4A a potential replacement for the cancelled Lockheed Martin/Boeing DarkStar stealth UAV. Senior USAF officials are said to be seriously considering major modifications to the Global Hawk to make it more versatile. The Block 20 version would have a larger wing and a more powerful powerplant, allowing it to carry a more than 900kg (2,000lb) payload.

In 1997, Lockheed Martin Skunk Works unsuccessfully pitched an unmanned variant of the U-2 high-altitude reconnaissance aircraft to the USAF. The U-2U variant would have augmented the mannedÊU-2S for very long-duration, high-risk missions.

Since then, the company has advocated new production of the long-lived manned U-2 to avoid a mission shortfall beginning in around 2006. The USAF has 31 General Electric F118-101-powered U-2S and four U-2ST trainers. However, only one-third are available for missions at any given time. They are undergoing a major cockpit upgrade, and the type's principal sensor, the Raytheon Advanced Synthetic Aperture Radar System 2, is being improved to keep the fleet operational through 2015 or beyond.

Industry sources say the USAF's Air Combat Command last year fought unsuccessfully for an attrition buy of 13 U-2s. They say non-recurring costs would be below $38 million, since retooling would not be required for low-rate production, and each U-2 would cost $28 million.

In comparison, each production Global Hawk would cost an estimated $15 million, offering much longer range and endurance than the U-2. But the U-2S has twice the payload, can operate easily in civil airspace, and is more versatile. Senior DoD officials are staunch supporters of the Global Hawk, but USAF Secretary Whitten Peters says Global Hawk and the U-2S can co-exist.

"We think the way to go is an integrated Global Hawk/U-2 solution. Each has capabilities the other does not, each has shortfalls the other does not," he says. But a funding shortfall remains the critical issue. An industry source says "everybody talks about complementary capabilities, but the budget situation puts them in competition." Also competing for funding is the Discoverer II space-based radar technology demonstration programme. Warfighters in the field would be able to task the Discoverer II sensor to look for ground-moving targets and focus on fixed locations.

Meanwhile, a U-2 replacement, dubbed the U-X, remains under USAF consideration, and the US Defense Advanced Research Projects Agency is seeking industry ideas on a proposed Quiet Supersonic Platform to demonstrate technology for a quiet, long-range, supersonic reconnaissance aircraft.

The Air Force Research Laboratory is formulating a Sensor Craft programme that promises to provide advanced ISR capabilities. The long endurance UAV would provide detailed theatre air and ground target detection, identification and tracking, using a unique combination of advanced sensors. The Sensor Craft would be the aircraft component of a fully integrated ISR system to also include ground-based space assets.

Source: Flight International