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This article was Originally Published on Jul 01, 2002 in Volume: 1  Issue: 3

From Reel to Reel

Once the stuff of sci-fi movies, pilotless combat aircraft are now a reality

By David C. Walsh

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In late May, project managers from the Boeing Co., the Air Force Research Laboratory, and the Defense Advanced Research Projects Agency (DARPA) made a surprise announcement. For the first time, they told reporters in a national teleconference, they had sent aloft a pilotless combat jet - an aircraft whose performance had left them more than pleased. It was the X-45A Unmanned Combat Air Vehicle (UCAV), whose nonflying version had been rolled out for public view less than two years before.

Launched from the dry lakebed of Edwards Air Force Base, CA, the aircraft flew for 14 minutes and reached 195 knots at about 7,000 feet. The X-45A did all that was expected of it during its first demonstration flight. Only basic flight characteristics and command links with the control station were tested, though, and the landing gear remained down. (The demonstration aircraft is expected to fly every two or three weeks throughout the summer, and the Air Force hopes combat-ready versions will join the inventory in 2008.)

The chief significance of the demonstration flight is this: Unlike older members of the unmanned air vehicle (UAV) family, the X-45 is the first such remote-controlled aircraft designed specifically for warfare. Drones like the current Predator are reconnaissance vehicles primarily, weapons platforms incidentally.

UCAV, its enthusiastic creators maintain, is the "revolutionary, transformational solution" to the age-old problem of safely conducting preemptive strike and suppression-of-enemy-air-defense (SEAD) missions. None is more hazardous for a pilot.

Advanced technology on the production version of the robot plane, the officials also said, should be able to deal with the challenge of sending it into what may be a crowded battlespace.

Auspicious start

With 1930s Buck Rogers fantasies realized at last, it was an auspicious start. But as elsewhere in life, where the devil's in the details, there had to be more to this story.

During the press conference and a later interview, MAT learned some of these details from UCAV co-manager Colonel Michael Leahy, an Air Force officer attached to DARPA. He's been the UCAV point man for two years.

Was there, for example, an interface expected between pilots of current Air Force warplanes and the "battle managers" who will launch and operate several (probably four) X-45s at a time? "Yes, there will be," he answered. "You may have four [UCAVs] that have a battle manager, and up to maybe four battle managers supporting a strike commander. That strike commander will interface with the rest of the force package, no different than a strike lead would for a manned package today."

According to Leahy, the Air Force intended to put these UCAVs seamlessly into the force structure - that is, operate them from the same runways and in the same patterns as the other elements of strike packages. Their exact role, he observed, will depend on the success of the demonstrations.

There is, however, a related and, to some observers, overarching issue at stake. Simply put, it is how operators, busy managing the four-aircraft X-45 strike packs, can keep them and other planes, manned and unmanned, from colliding during training exercises. Or, more worrisome, during aerial combat. The issue becomes one of communications links among unmanned planes like the X-45 and Predator and manned ones like the F-18 Hornet and F-22 Raptor.

'Programmed, coordinated flight'

Leahy agrees that the operator has a lot of responsibilities, but likens the collision avoidance strategy for the UCAV with other current strategies. Different tasking and the assignment of specific airspace are the keys. As for other platforms, moreover, Link 16 messaging on Joint Tactical Information Distribution System terminals is available for the UCAV. This will allow the vehicle to achieve something on the order of "programmed, coordinated flight," defined as a key concept for the program. In Leahy's view, this will help ensure that the vehicles are "communicating their relative positions to each other to keep them in formation and to keep them from running into each other."

Leahy also noted that the management team is working on sophisticated algorithms that will enable the mission control operator, from his console, to size up threats along a particular vector and, as necessary, command the vehicles to take evasive maneuvers. He acknowledged, however, "Right now there's nothing active on the vehicle to prevent it from striking another vehicle; we don't have any radar or anything telling us there's something around [it]." Final interoperability protocols remain undefined.

Leahy indicated, however, that the potential for this worst-case scenario was overstated. "The airspace is going to be pretty sparsely populated to begin with," he stated, "so we're not in a tight package with [many aircraft]." While the aircraft interoperability - i.e., communication - issue "has to be dealt with," Leahy called it "a solvable challenge using the technologies we have available."

The human factor

On how closely engaged the human element was, he stressed, "The key to that is the kind of decision aids that can reach [the single operator]. What we're looking at is a kind of supervisor. That person has several 'workers,' which are all the UCAVs that are flying. Those workers have been 'trained,' and they have certain sets of rules of engagement that they follow."

The aircraft contains multiple permission layers that require it to consult with the operator. Leahy added that sometimes "every single action that vehicle takes has to be approved by an operator."

Touted as an all-weather plane, the X-45B - a later UCAV version - will also be equipped with night-vision devices. "We want to be able to operate in the same basic environment that any other tactical aircraft can operate in," Leahy said. "The B [version] will be capable of that. The A's are not."

Measuring 27 feet long with a 34-foot wingspan, the X-45A can be stored unassembled in a small container for up to 10 years. Six can fit in the hold of a C-17 Globemaster III.

Although about half the size, and rather flat and canopy-less for a stealthier capability, the X-45 resembles a conventional manned jet. And sounds like one, according to Boeing UCAV Manager Rich Alldredge, who witnessed the maiden flight and appeared with Leahy at the press conference.

An antenna protruding from the X-45 is a simple UHF transmitter, but that may change. "We are notionally looking at being able to leverage the MILSTAR [Military Strategic, Tactical and Relay] satellite capabilities," Leahy said. Various transponders and line-of-sight communications are being hashed over as well.

Safeguarding the bird

One important aspect of any UAV is recoverability. Not only is cost savings a factor; in case it's downed, a "bird's" intelligence capabilities and technology need to be safeguarded. "We intend to recover UCAV with the same probability as manned asset recoveries," Leahy observed. "In that regard, these vehicles are more similar to a current tactical aircraft than they are to any other UAV out there."

But the UCAV's "real transformational piece," he emphasized, is "eventually taking the 'smarts' that are on the ground - the ability to do dynamic re-tasking and real-time auto-routing and prioritization of targets - and migrate that capability onto the air vehicles themselves." All this will mean "minimal intervention by the operator."

The UCAV manager stressed that the knowledge, skills and attributes of the ideal operator are still under study. The current X-45 "force" includes Predator operators, civilian personnel, experienced SEAD mission personnel and fighter pilots. One of Leahy's test pilots is a Global Hawk operator who deployed that advanced, noncombat UAV from the United States to Australia last year.

Some, Leahy said, are "lieutenants who have more experience playing tactical decision games across the Internet than they do flying a vehicle." For the next three to four years such "test operators" will predominate. Personnel won't sign up for this duty until 2007 or 2008.

Regarding weapons systems, Leahy wasn't too specific. "We're designing the X-45 to have a fair amount of payload flexibility," he said. For now, SEAD mission armament is limited to the high-tech Small-Diameter Bomb (SDB) and Joint Direct Attack Munitions.

Both are Global Positioning System-guided munitions. One variant of the 250-pound SDB, says the Boeing Co., is equipped with a guidance system suitable for fixed and stationary targets. Another adds a terminal seeker with automatic target recognition capabilities more suitable for mobile targets. (Currently, one of the X-45's bays is empty; the other holds an avionics pallet, Leahy said. The B variant, or "fieldable prototype," will be configured differently.)

Defensive arms unnecessary

Some analysts have posited the need for the pilotless combat aircraft to carry defensive arms like a mini-gun. Leahy disagrees. "This isn't flying low and slow like a Predator, " he reported. Instead, UCAVs will operate at 40,000 feet.

Raptors or other manned jets that constitute a strike force could likely neutralize threats to the UCAV, he told MAT. Airborne Warning and Control System (AWACS) planes may also help defend the UCAV. "There's no reason why there can't be a UCAV operator on an AWACS," Leahy disclosed. Such a move would depend on "how we are conducting operations."

Leahy was especially careful to stress what has been a tough concept for some to grasp: the differences between the X-45 UCAV and the Predator- or Global Hawk-type UAVs.

"First, nobody 'flies' the UCAV," he added. "The Predator guy is flying an airplane; it is a remotely piloted vehicle. You can't take the pilot out of that loop. In our case, all those functions are already inherently in the vehicle itself. It is flying a mission plan."

Underscoring the distinction, Leahy explained, "The operator, in our vision, does not worry about flying. He's worried about upper-level tasks: Where do I want to go next? How do I want to engage the enemy? How do I want to process this information to give top-level IDA [Integrated Digital Avionics] intent and guidance to the vehicle?"

If a UCAV operator becomes disabled or cannot handle the workload, "The system is designed [so] he can pass control of those jets to someone else, or to another mission control station that's in the same trailer, or to another trailer or node that's on the network."

Demonstrations, which will continue through next spring, should establish how many aircraft will be controlled by a single operator and for how long, he said. Current thinking favors one operator controlling four UCAVs.

Another key difference between the X-45 and Predator is how each copes with trouble. "The Predator is a flight vehicle, so it doesn't have the autonomous systems to land itself. Ours does," Leahy said. Even if all command and control links fail, "UCAV will follow a contingency route back home and land, roll out and stop its engine. And that's active today," he added.

Human factor

DARPA Director Dr. Anthony Tether discussed UCAVs during testimony before the Senate this April. "The vehicles have sophisticated onboard adaptive mission planning, which will allow them to conduct the entire mission without continuous human oversight," he noted.

Humans, however, have an important role to play. "This is not about autonomous machines. It is about blending the best traits of man and machine," Tether said.

Cooperation, not competition, is the name of the UCAV game. Leahy expects that although the Air Force is the "pathfinder," the aircraft, once validated, will be used by multiple services. "It doesn't matter what color your uniform is. If you're in charge of that strike pack, then you will have control over those assets - whether they take off from a carrier or from the ground," he added. "Up and away, we don't envision any difference" from a command standpoint.

Whether the Pentagon expects the X-45A or later B model to become a fighter of choice remains unclear. "What this program is trying to do," he said, "is to get the data needed to answer those kinds of questions. Our role is to go out and explore the space, and find out how transformational and revolutionary we can be."

Leahy added, "We're not at all looking here at what the ultimate objectives may be or where it could go in the future."

Indeed, many system validation tests and other demonstrations are yet to come, with operational UCAVs not appearing until 2008. Exact numbers are not being publicly revealed, although some believe the Air Force will get hundreds.

Officials were satisfied by the first demonstration. "The aircraft from liftoff was very, very stable in all regards," Boeing's Alldredge said. "The whole flight path went just as we had expected, as we had seen in our simulations. We limited the bank angle to 20 degrees, and it performed just as expected. It rolled up nicely into the banks.

"All the climb profiles were extremely nominal," he added. "As we came in and did our calibrated air speed checks, the system was within a few units [in altitude and air speed] of our expectations."

Leahy equated the flight with "one air lap around the Indy 500 racetrack." The X-45's taxi speed, approach and landing tests were just as impressive.

Testing, testing

Yet the demonstration flight was not intended to "press the performance envelope" or showcase the plane's maximum battlespace capabilities, the UCAV project managers cautioned.

Tests of multiple vehicles will begin next summer, Alldredge reported. Weapons delivery tests will commence in 2003 or 2004. Live-fire exercises are planned for the following year. The B variant will have more tests next year and should be ready in 2007 or 2008. That version will include mission control systems, storage containers and support equipment.

Regarding speculation that UCAVs would cut into the Joint Strike Fighter (JSF) program, Leahy replied sharply in the negative. "UCAV is not designed to be a direct replacement for anything that we have in our current inventory," he stated. Rather, the UCAV would complement planes like the JSF, F-22 and other newer warplanes - not make them obsolete, he asserted.

Leahy suggested a UCAV future that's as bright as its near-term schedule is busy. "Sometime in August, we're going to go out and pull the gear up - and that's a major system check," he said. "From there it will be multi-ship ops, which will go into summer of next year.

"In conjunction with that, we're doing a whole host of mission simulations that will prove the functionality, the 'four-to-one' [UCAV-to-operator ratios] and everything else," he said. "The graduation exercises and Block 2 are really the seminal events for UCAV as we understand it today. That's where we get the things that have never been done by anybody else before, and get to this new kind of functionality that's beyond the state of the art."

Completing that graduation event late next summer and designing the fieldable prototype - the X-45B - are "two key elements that will fuel the next major decision on the way forward," Leahy noted.

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