Combat drones: clouds on the horizon for pilot-less bombers.

After years of steady growth in funding, development and operational use, unmanned aerial vehicles have begun to rival--and, in some cases, exceed--the capability of manned aircraft.

The rapid maturing of military UAVs into armed unmanned combat aerial vehicles was seen in one of the most promising armed drone programs, the joint unmanned air combat .system, or J-UCAS.

"Supporting military operations in both Iraq and Afghanistan, unmanned aircraft have transformed the current battle space with innovative tactics, techniques and procedures." reads the foreword to the defense Department's 25-year UAV roadmap, published in August 2005. "Unmanned air vehicles not only provide persistent intelligence, surveillance and reconnaissance, but also very accurate and timely direct and indirect fires."

This blending of the previously stove-piped missions--intelligence, surveillance, reconnaissance and direct fires--is one of the major strengths of one of the most popular UAVs, the General Atomics Predator. Predators armed with Hellfire missiles can orbit a battlefield undetected, for hours at a time. They can sock time-sensitive targets with day and night sensors--and kill these targets within minutes.

Predators debuted in combat over Bosnia in the mid-1990s. In 2002, an armed Predator operated by the Central Intelligence Agency spotted and killed senior al-Qaida leader Abu Ali in Yemen. Within a few years after the Ali assassination, armed Predators had migrated to the Air Force and were conducting limited dose-air support missions over Iraq.

The new Predator B model features a more powerful engine and a larger airframe to boost the bird's combat load. The B model's multi-mission MQ-1 designation--versus the original's RQ-1 for reconnaissance--reflects the ascendance of the Predator's armed capability.

For all their successes, armed Predators lack the performance and weapons payload to take out well-defended targets on a high-intensity battlefield--and survive. Over western Iraq, where firefights between Marines and insurgents are a daily occurrence and the threat from ground fire and shoulder-fired missiles is real. Marine Corps and Air Force manned fighters are providing the most air support.

These manned platforms are equipped with mounted sensor pods that give them many of the same ISR capabilities as Predators, albeit with less endurance.

But in the military's stable of UAVs, armed Predators are only a stopgap--an experimental measure pending the introduction of purpose-designed combat drones--known as joint unmanned combat aerial vehicles. A J-UCAS drone would have traded some of the Predator's surveillance and reconnaissance chops for the performance and survivability to supplement Air Force F-16s and A-10s and Navy F/A18s in the close-air support and battlefield interdiction missions.

J-UCAS began its life at the Defense Advanced Research Projects Agency in 1998. Both Boeing and Northrop Grumman built jet-powered demonstrators: the X-45C and the X-47B, respectively. The X-45 was equipped for in-flight refueling and optimized for Air Force missions that demanded a high degree of stealth. The X-47 was less stealthy, but longer-ranged and designed to operate from Navy aircraft carrier decks.

After seven years of successful design and testing, in November 2005, the Defense Department transferred J-UCAS to a joint Air Force and Navy office and scheduled a fly-off between the demonstrators.

But then the February 2006 quadrennial defense review directed the Navy to wholly take over J-UCAS management. In the 2007 defense budget, the Air Force redirected the J-UCAS funding to a new, vaguely defined, "next-generation long-range strike" development program that, according to observers, is likely to include a mix of unmanned and manned bomber aircraft.

Just months after its graduation from fringe research status to major procurement program, J-UCAS had been downgraded to Navy UCAS, or N-UCAS. The X-47 was largely unaffected, but the X-45 had lost its sponsor and, it seemed at first, any hope of ever reaching production.

Boeing's program manager for unmanned combat air vehicles, David M. Koopersmith, said there was initial disappointment at the company, because the X-45 was showing enormous potential and reaching unprecedented performance milestones.

"We were driving toward the first X-45C flight in early 2007, but we understood that sometimes our customer changed priorities," he said in an interview. "So we as a team have shifted the focus to those changed priorities."

Koopersmith's team of engineers currently is designing a new unmanned combat aircraft for the Navy. The company expects to have a "demonstrator" aircraft by 2011.

It is not yet clear what will happen to the Air Force's three UCAVs --two X-45A's and one X-45C. The two smaller aircraft are warehoused at Edwards Air Force Base, Calif. The larger X-45C is at a Boeing facility in St. Louis. "We are working with the government to disposition all the assets," Koopersmith said.

Several Air Force spokesmen who were contacted by National Defense declined to comment on the issues surrounding the decision to end the X-45 program.

In the eyes of many critics, the Air Force surrendered its first realistic opportunity for a truly revolutionary and affordable air combat capability.

One Boeing employee who worked on the X-45 program said the Air Force's about-face was a long time coming. He asked to not be quoted by name because his views do not reflect the company's official stance.

"We knew even from early 1999 and the original X-45A UCAV contract that we were fighting a political, cultural and budget prejudice that could kill us," said the employee. Many of the Boeing workers from the X-45 program, he said, were angered by the abrupt cancellation of J-UCAS just when they were nearly "on the cusp of making history in the aviation world."

The Defense Department had budgeted $1.8 billion for the X-45C and the X-47B. "We thought that we were mostly out of the woods," said the Boeing employee.

He speculated that the Air Force's decision to withdraw from the program was partly financial--mostly to ensure that the J-UCAS would not drain any procurement funds from high-profile manned aviation programs such as the F-22 and the F-35 fighter jets. Another possible explanation for the Air Force backing away from J-UCAS, the Boeing employee said, is that the X-45 was running headlong against the Air Force's pilot culture that prefers dropping bombs from cockpits, rather than from ground control centers.

Ironically, the Boeing employee said, one of the prime directives in the X-45 program had always been to reduce operational costs by designing a system that didn't require a pilot.

In several computer simulations, the X-45 promised to do more than provide an existing capability at lower cost, he said. "Our number-one strategy we were focused on was excelling at most of the JSF missions so that the Air Force couldn't ignore us," the Boeing source said. "This got rapidly revised once the people up top figured out that ... folks in the Department of Defense who were staking their futures on the JSF would have a hard time reconciling developing both systems." The strategy then shifted to "selling the X-45 to do the worst down-and-dirty missions that even the nuttiest pilot wouldn't want to do."

If the Air Force ultimately decided that the UCAV was too expensive, it did not explain why, the Boeing employee said. "You can play games with per-unit cost by changing how many systems you divide into the development cost. You will note that the Air Force never said publicly in some seven years how many X-45s they thought they would ever procure."

The reason, he hypothesized, was that large purchases of drones would have reduced the unit cost of the aircraft to a fraction of the JSF's.

The program director for J-UCAS, Navy Capt. Ralph N. Alderson, explained in a written statement to National Defense that the restructuring of the program was necessary to comply with the QDR'S "holistic view of future needs ... and the transitioning of J-UCAS technologies into other programs." Lessons learned from the J-UCAS program "will be available to any follow-on efforts."

In the wake of Air Force's J-UCAS pullout, drone manufacturers are cautious, but optimistic about the future of this technology.

General Atomics manager John Porter stresses that systems such as Predator are intended to supplement, rather than replace manned aircraft.

Porter said Predator fills an entire new niche. "[Manned fighters] take off knowing where they're going and what the target is. We don't," he said.

Over Iraq and Afghanistan, however, tactical fighters fly scheduled orbits over contested areas, using sensor pods such as Sniper and Litening and calling on forward air controllers to spot new targets that they immediately attack. This blending of the surveillance and close-air support functions was pioneered by Predator but, with the advent of high-fidelity sensor pods and small precision-guided munitions, has migrated to manned jets.

It's in this arena where today's F-16s and F/A-18s square off against UAVs in a fight over roles and missions of tactical aviation.

The clash reflects narrow thinking, according to one Air Force officer. Col. Christopher Jella is the commander of the 18th Reconnaissance Squadron, the newest Global Hawk unit. From Beale Air Force Base in California, Jella oversees pilots and sensor operators who control 120-foot-wingspan reconnaissance drones that are launched from forward locations in Southwest Asia.

"I think a lot of the mysticism with UAVs comes with the fact that we've lumped them all into this UAV [rubric]," Jella said. "Remember, back in 1920, you had this thing called an 'airplane', and you had the same problem.

"What we now call UAVs represent so many diverse aircraft performing such diverse missions that it's pointless to generalize about them--and pointless to compare them to manned aircraft," Jella said. What's more, he adds, the Air Force should be interested in "effects," not specific hardware.

"Our specific effect is high-altitude intelligence surveillance and reconnaissance. With that in mind, there are no people on board, no cargo--there are cameras. That's the kind of platform we're talking about. But it's an aircraft because we want to operate in the [same] airspace [as manned aircraft]. We want manned aircraft [crews] to feel that they're safe to continue to fly in their airspace. We need to operate right next to them and abide by the same rules."

That the Global Hawk pilot is sitting on the ground rather than in a cockpit makes him no less a pilot, Jella contends. "You have a pilot in the loop," he stresses. "I have a pilot in a ground station physically controlling [Global Hawk]. On a 24-hour flight, we leave it in autonomous mode for just four hours. The other 20 is all manual flight--it's with a keyboard and a mouse, but there's a man in the loop."

In that sense, Jella said, manned aircraft have a lot in common with drones. Pilots directly control all of these aircraft, albeit from a ground station in the drones' cases. Jella contends that the physical location of the pilot is less important than the issues of control and safety--and drones are perhaps better controlled and safer than manned aircraft.

"What'll happen in a manned aircraft, at the moment something [bad] happens ... all of the sudden, the pilot is off the mission and now he's focusing on this new thing. That's where a lot of pilots make their money--when things go wrong. What we have done is go through that thought process long before the aircraft even takes off. And we can staff these things to have two or three people" at the ground control station trying to fix a problem. "A single engine pilot, he makes a mistake, he pays for it. He's all alone."

Air Force senior leaders say UAVs are here to stay. "We're going to see more unmanned [systems]. Some people describe the Air Force as resisting that ... This is absolutely not the case," said Lt. Gen. Donald Hoffman, military deputy at the office of the assistant secretary of the Air Force for acquisition. Speaking at a Defense News Media Group conference, Hoffman said that "persistence" is the main attribute that makes UAVs valuable to the Air Force.

David L. Vesely, a retired Air Force lieutenant general, said he never saw a "cultural aversion" to unmanned aircraft during his 33-year career as a fighter pilot. The belief that pilots fear UAVs will take over their jobs mostly is an "urban myth," Vesely said in an interview. On the other hand, he said, "There are valid reasons for retaining pilots in cockpits: the sophistication of the human thinking process and the human sensors have yet to be replicated by a computer."

Financial considerations also may have factored into the Air Force rethinking of the X-45, said Vesely. In the earlier days of unmanned aircraft programs, the Defense Department expected that they would cost much less than manned aircraft. "That hasn't been the case," he said. A case in point is Global Hawk, which has seen its price tag balloon in recent years, and currently is estimated to cost nearly $80 million per aircraft. And even though there is no pilot, there are human operators who must be paid and supported. "Costs savings from UAVs have not materialized in the bottom line," Vesely said. "It's counterintuitive, but it's true."

Independently of any cultural resistance, "reconnaissance and air-to-ground [missions] are obvious candidates for UAVs replacing piloted aircraft," said military expert John Pike from the think-tank Globalsecurity.org. He adds that drones show great promise in standoff air-to-air missions, too.

There's some recent good news for the Xo 45 in the wake of the Air Force's withdrawal from J-UCAS. Capt. Steven Wright from the Navy's UAV office said that the Boeing UCAV will be modified for carrier operations and demonstrated against the X-47 as part of N-UCAS. "We're still moving out to demonstrate an ability to operate from a carrier by 2011. That will inform a decision to produce or not produce a follow-on program."

Additional reporting by Sandra I. Erwin