Out of the Black: Meet the RQ-180

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EXCLUSIVE: Secret New UAS Shows Stealth, Efficiency Advances
By Amy Butler
Aviationweek
December 6, 2013

A large, classified unmanned aircraft developed by Northrop Grumman is now flying—and it demonstrates a major advance in combining stealth and aerodynamic efficiency. Defense and intelligence officials say the secret unmanned aerial system (UAS), designed for intelligence, surveillance and reconnaissance (ISR) missions, is scheduled to enter production for the U.S. Air Force and could be operational by 2015.

Funded through the Air Force's classified budget, the program to build this new UAS, dubbed the RQ-180, was awarded to Northrop Grumman after a competition that included Boeing and Lockheed Martin. The aircraft will conduct the penetrating ISR mission that has been left unaddressed, and under wide debate, since retirement of the Lockheed SR-71 in 1998.

Neither the Air Force nor Northrop Grumman would speak about the classified airplane. When queried about the project, Air Force spokeswoman Jennifer Cassidy said, "The Air Force does not discuss this program."

The RQ-180 carries radio-frequency sensors such as active, electronically scanned array (AESA) radar and passive electronic surveillance measures, according to one defense official. It could also be capable of electronic attack missions.

This aircraft's design is key for the shift of Air Force ISR assets away from "permissive" environments—such as Iraq and Afghanistan, where Northrop Grumman's non-stealthy Global Hawk and General Atomics' Reaper operate—and toward operations in "contested" or "denied" airspace. The new UAS underpins the Air Force's determination to retire a version of the RQ-4B Global Hawk after 2014, despite congressional resistance. The RQ-180 eclipses the smaller, less stealthy and shorter-range RQ-170 Sentinel.

If the previous patterns for secret ISR aircraft operations are followed, the new UAV will be jointly controlled by the Air Force and the CIA, with the program managed by the Air Force's Rapid Capabilities Office and flight operations sustained by the Air Force. This arrangement has been used for the RQ-170, which is operated by the Air Force's 30th Reconnaissance Sqdn., according to a fact sheet the Air Force released after one of the aircraft turned up in Iran.

Northrop Grumman's financial reports point to a possible award of a secret UAS contract in 2008, when the company disclosed a $2 billion increase in the backlog in its Integrated Systems division. This is the operating unit responsible for building the B-2 bomber, Global Hawk and Fire Scout UAS and X-47B unmanned combat air system (UCAS) demonstrator. This year, Northrop Grumman financial reports acknowledged that an unnamed aircraft program entered low-rate initial production, the Pentagon term for low-volume deliveries that begin as testing nears completion and before the program is approved for full production.

Beyond the financial disclosures, publicly available overhead imagery shows new shelters and hangars sized for an aircraft with a 130-ft.-plus wing span at Northrop's Palmdale, Calif., plant and at Area 51, the Air Force's secure flight-test center at Groom Lake, Nev.

The company also pushed for a substantial expansion of its Palmdale production facilities in 2010, perhaps to support work on the RQ-180 (AW&ST Nov. 22, 2010, p. 28).

The new aircraft's existence explains an inconsistency: Air Force officials have frequently called for a new, penetrating ISR capability. Yet there has been no public evidence that the service has been planning to develop such an aircraft.

At a House Armed Services Committee hearing in April, Lt. Gen. Charles Davis, the Air Force's top uniformed acquisition official, said the service has no requirement for more Global Hawks beyond 2014 and wants to "use that money for much higher priorities."

Defending the planned cuts to the Global Hawk, Davis said, "We did not do that without carefully looking at how we cover that [mission] with the U-2 and other classified platforms." But when asked during the open congressional hearing to explain, he said, "You'd probably need to go into detail within another forum."

In September, Lt. Gen. Robert Otto, the Air Force deputy chief of staff for ISR, said the service's "first priority" in intelligence, surveillance and reconnaissance is "to rebalance and optimize our integrated ISR capabilities.

"The mix is not where it needs to be," he said. "We are over-invested in permissive ISR and we have to transform the force to fight and win in contested environments. We will seek a more balanced fleet of both manned and unmanned platforms that are able to penetrate denied airspace and provide unprecedented levels of persistence."

The Air Force could not afford to buy and maintain the target number of 65 MQ-9 Reaper and MQ-1 Predator combat air patrols beyond 2014, Otto added, possibly pointing to a shift in priorities to the new Northrop system.

These public statements are a byproduct of an internal debate over the number of the new secret UAS to be acquired. While there is apparently agreement on the need for a small "silver-bullet" force for special military and CIA missions, a larger fleet could be an enabler for fighters and bombers against a wide range of targets. A 2009 report by the influential think tank the Center for Strategic and Budgetary Assessments recommends a force of five 10-aircraft squadrons of high-altitude, stealthy, ISR unmanned penetrators. But such a large fleet would be costly and could compete for funding with the Joint Strike Fighter, the Long-Range Strike Bomber and other high-priority programs.

In addition, if the U.S. procures more than a few of the secret RQ-180 aircraft, it will be harder to keep them under wraps. Historically, the Air Force has resisted establishing operational units at Area 51, its most secure known operating base, because maintaining compartmentalization there between multiple secret programs becomes difficult. For example, workers are usually confined to their buildings when a classified program other than their own is performing tests outside. The disruption to work grows if one program is running at an operational tempo.

In April, Otto's predecessor as deputy chief of staff for ISR, Lt. Gen. Larry James, acknowledged that the Air Force had learned lessons about the need to more widely disseminate information on classified programs to ensure operational commanders are fully aware of their capabilities. Responding to a question from Aviation Week at a Stimson Center event in Washington, James said, "We have a whole host of programs covering all the different environments, and we ensure that as we develop new capabilities we are in conversations with people at the right levels. We are much better today than we were 10-15 years ago, [when] you'd have this new super-secret thing and you'd turn up at the combatant commander's door at the start of an operation. That's not a good place to be."

The RQ-180 has its roots in Northrop Grumman's Joint Unmanned Combat Air System (J-UCAS) project. The main reason for J-UCAS's cancellation in late 2005 was the divergence in requirements. The Navy wanted a carrier-based aircraft, which led to the X-47B program. The Air Force sought a larger, longer-range "global strike enabler" that would be much more capable than the RQ-170, which was then being developed.

A fiscal 2007 Navy budget document disclosed that the J-UCAS program had been split in December 2005 into a Navy demonstration effort (which led to the X-47B) and "an Air Force classified program." At the same time, Northrop openly discussed a range of longer-winged X-47C configurations, the largest being a 172-ft.-span design with two engines derived from General Electric's CF34 and capable of carrying a 10,000-lb. weapon load.

The RQ-180 is smaller than that concept, and it is not clear whether it will conduct strike missions. It is similar in size and endurance to the Global Hawk, which weighs 32,250 lb. and can stay on station for 24 hr. 1,200 nm from its base. The much smaller RQ-170 is limited to 5-6 hr. of operation.

A key feature of the RQ-180's design is an improvement in all-aspect, broadband radar cross-section reduction over Lockheed Martin's F-117, F-22 and F-35. This is optimized to provide protection from low- and high-frequency threat emitters from all directions. The design also merges stealth with superior aerodynamic efficiency for increased altitude, range and time on station.

The aircraft uses a version of Northrop's stealthy "cranked-kite" design, as does the X-47B, with a highly swept centerbody and long, slender outer wings. Northrop Grumman engineers publicly claimed (before the launch of the classified program) that the cranked-kite is scalable and adaptable, in contrast to the B-2's shape, which has an unbroken leading edge. The RQ-180's centerbody length and volume can be greater relative to the vehicle's size.

Computational fluid dynamics permit new stealth aircraft to achieve "sailplane-like" efficiency, industry officials say. The management of complex three-dimensional airflow is the key to achieving laminar flow over much of the wing and designing stealth-compatible exhaust and inlet systems that are lighter and more efficient than those on the B-2.

Aerodynamics and stealth are often at odds. The B-2's "toothpick" leading edges—sharp at the nose and wingtip and blunter in between—are the result of a hard-fought trade-off between the team trying to optimize aerodynamic performance and the group concerned with making it hard to detect. Maintaining a high degree of laminar flow on a swept wing is an achievement in itself, because spanwise air flow tends to induce turbulence and is not made any easier by possible spillage from overwing inlets.

The pursuit of laminar flow and efficiency likely drove the development of new structural and manufacturing technologies. Scaled Composites, which Northrop Grumman acquired in 2007, is a world leader in building large composite airframes "outside-in" in female molds, resulting in a consistent and fastener-free surface.

Engine integration always presents challenges for stealthy designs. The length and volume of the serpentine inlet and exhaust systems (used to shield metal engine components from radar) are proportional to engine diameter, because the duct curvature radius must increase with its area to avoid distortion. Also, higher-bypass engines, which are larger in diameter, tend to be less tolerant of flow distortion than low-bypass types. This is one reason why most subsonic stealth aircraft, including the B-2, use adapted fighter engines at a significant penalty to fuel economy.

The RQ-180 could use a medium--bypass-ratio engine, similar to the modified CF34 engine eyed for early X"‘47-based concepts. Its engine probably has more power than the Global Hawk's 7,600-lb.-thrust Rolls-Royce AE3007H, to provide better altitude performance and electrical power for payload growth.

Operationally, the RQ-180's range could be extended by inflight refueling, though it is unclear whether the UAS takes advantage of this technology. Before 2008, Northrop Grumman repeatedly stated its belief that the endurance of an X-47-based aircraft could be pushed to 100 hr. with refueling. Beyond that point, the need to reengineer components to extend the time they could be flown between inspections was predicted to be burdensome. The limiting factor on Global Hawk endurance beyond its onboard fuel capacity is oil life.

The Navy pursued probe-and-drogue refueling under the X-47B program, but it used a manned surrogate aircraft for flight tests. The Air Force separately conducted tests in 2008 using its boom-equipped tankers and a manned surrogate, but after 2008, no progress with boom refueling of unmanned aircraft was reported publicly.

Incorporating advances in stealth and aerodynamics, the RQ-180 shows that low-observable technologies can still adapt to counter new threats such as low-frequency radar. It is a stepping-stone to the development of the Air Force's Long Range Strike Bomber, while also complementing the B-2 and other long-range strike assets. By contrast to its predecessors, the RQ"‘180 secures a foothold for stealth in future war plans, in which extremely expensive "do everything" platforms are eclipsed by families of networked, cooperative systems.

Secret New UAS Shows Stealth, Efficiency Advances

 

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Where Does RQ-180 Fit In Stealthy UAS History?
By Amy Butler
Aviationweek
December 6, 2013

In December 2011, Iran proudly displayed on state television a stealthy U.S. unmanned aircraft it claimed it had downed while conducting reconnaissance overflights. The trophy was a Lockheed Martin RQ-170 Sentinel, an aircraft publicly acknowledged by the U.S. Air Force two years earlier.

Even before, the existence of the RQ-170 had been a poorly kept secret. The unmanned aerial system (UAS) was operating out of Afghanistan and flying over Pakistan and Iran for an undetermined period before it was photographed at Kandahar AB, Afghanistan, in 2008. Later, in 2011, it was involved in the raid in which Osama bin Laden was killed (AW&ST Dec. 12, 2011, p. 19).

The Pentagon played down that embarrassing loss of the UAS. One reason may now be clear. Defense and intelligence sources say the Sentinel was the result of a quick-reaction project designed for specific missions, and not with an eye toward an enduring presence in the fleet. That position was reserved for a new, secret UAS—Northrop Grumman's stealthy RQ-180.

To fully understand this new UAS, one must view it in the context of the larger "family of systems" the Air Force envisions to include long-range strike and intelligence, surveillance and reconnaissance (ISR) platforms. A 2010 presentation by the Air Force's director of operational requirements at the time, Maj. Gen. David Scott, made that connection.

Emergence of the RQ-180 allowed the Air Force to reduce requirements for what was once called the Next-Generation Bomber (NGB), a program terminated in 2009 because of its high cost. The follow-on Long-Range Strike Bomber (LRS-B) is a less-expensive option that will rely on interoperability with the RQ-180 and other systems in the family.

In 2008, when Northrop is believed to have won the contract to develop the stealthy penetrating UAS, the Air Force was facing criticism from then-Defense Secretary Robert Gates that it was falling short in supporting ISR requirements for the wars in Iraq and Afghanistan. But behind the scenes, defense planners and the intelligence community were worried about a lack of information on some well-defended locations such as North Korea and Iran.

This was also in the wake of the Air Force and Navy's divorce over the effort to jointly develop a single stealthy UAS capable of ISR collection and striking from land or sea. The Joint Unmanned Combat Air Systems (J-UCAS) program was terminated late in 2005. The Navy, in search of carrier-based ISR, proceeded with the X-47B UCAS demonstration and now plans to buy a follow-on called the Unmanned Carrier-Launched Airborne Surveillance and Strike (Uclass) system. The Air Force directed its funding and technology to a classified program, likely the RQ-180.

Despite heavy pressure on defense spending, the RQ-180 is moving forward. Cuts to classified budgets are "relatively proportional" to those for white-world programs, says acting Air Force Secretary Eric Fanning. "This is the first time I've been in the Air Force where we've taken a really close look on the classified side to make sure the investments are closely aligned. We are not missing opportunities there to take cuts on the unclassified side...There were some shifts, [but] nothing overly major at this point."

Because of war requirements in Iraq and Afghanistan, where coalition air forces could operate with little threat from the ground, the Air Force had poured funding into ISR collectors without stealthy characteristics such as the Beechcraft King Air-based MC"‘12W Project Liberty and Blue Devil 1 intel platforms.

"For a decade now we have built the most incredible permissive ISR capacity and capability that anybody has ever seen," Air Combat Command's chief, Gen. Michael Hostage, said in September. "We are being forced to build a capacity [with the Reaper] I know I can't sustain, and I know I don't need based on the national strategy," which calls for operating in heavily defended airspace, as well. He says Pentagon officials are sorting through what is needed to handle the more challenging threats. "We are talking about the entire ISR construct—how much in permissive, how much in contested and how much in denied" is needed.

Not since the Mach 3 SR-71 program ended in 1998 has the Pentagon been able to overfly targets in hostile airspace to collect intelligence. The proliferation of longer-range and integrated air-defense systems, coupled with its high operating cost, banished the Blackbird to museums. And in 1999, the Pentagon terminated the RQ-3 DarkStar UAS, a potential successor under development by Lockheed Martin and Boeing as a stealthy adjunct to Northrop Grumman's RQ-4 Global Hawk, after it encountered flight-stability problems. These developments left unanswered a Pentagon Joint Requirements Oversight Council mission-need statement for an aircraft capable of operating in defended airspace for long periods.

Though satellites are capable of peering behind borders, they lack the persistence and flexibility of aircraft. Satellites are limited by slant ranges, a problem that aircraft can mitigate by altering their flight paths. Also, adversaries can predict when a spacecraft will fly overhead and adjust their operations accordingly.

High-speed platforms continue to be evaluated, such as Lockheed Martin's hypersonic SR-72 concept (AW&ST Nov. 4, p. 18), but planners leery of acquisition foul-ups and higher-risk technology opted for stealth in order to field a system as soon as 2015.

The expectation that the RQ-180 will be fielded soon has helped to cement support for the Air Force's abrupt change of heart on the Northrop Grumman Global Hawk high-altitude, long-endurance UAS—once the centerpiece for the service's ISR development plans. The Block 30 Global Hawk was eyed as a replacement for the manned U-2 for stand-off ISR collection, in which aircraft just loiter outside hostile airspace peering into enemy territory to gather images and signals. Though not able to fly as high (50,000-60,000 ft. versus the U-2's 70,000 ft.-plus), the Global Hawk could loiter for a day or longer and not expose pilots to the health hazards of prolonged missions at extreme altitudes, a problem during long flights supporting operations over Afghanistan.

Despite deeming Global Hawk critical to national security in 2011, the Air Force less than a year later proposed terminating the Block 30 version, citing the high operating cost it had once defended. The Air Force also cited lackluster performance of the Block 30's electro-optical and radar-sensor suite, despite earlier assertions that these issues were manageable (AW&ST June 13, 2011, p. 35).

Now the more advanced, stealthy RQ-180, capable of penetrating an adversary's airspace, has superseded the Global Hawk. The Air Force is now standing behind the U-2, with some cockpit and sensor upgrades, as its workhorse stand-off intelligence collector, with the RQ-180 poised to take on the penetrating mission.

In a high-level roles-and-missions trade, the Air Force assumed authority for developing a stealthier, longer-range, land-based UAS capable of penetrating the most defended airspace, guarded by advanced surface-to-air missiles and jammers. Meanwhile, the Navy, is mired in a debate over how stealthy to make its Uclass air vehicle when a high degree of stealth would push costs higher. With the Air Force operating the RQ-180, the Navy would have the option to cut its costs on Uclass.

Perhaps indicative of the debate, the Navy has been coy on the requirements and design specifications for Uclass. The Office of the Secretary of Defense and the Joint Staff are pushing for Uclass to operate only in "contested" airspace—the Pentagon's word for areas that are defended but not with the most advanced weapons systems. But Navy officials are hoping for a more survivable—though more expensive—design capable of operating over the best-defended areas or "denied" airspace, in Pentagon parlance."©Furthermore, the Air Force plans to retain its MQ-1 Predator and MQ-9 Reaper UAS for operation in uncontested or lightly contested airspace. The so-called MQ-X, which was to be a Reaper follow-on, disappeared from Air Force long-range planning in 2012, another sign its UAS planning was refocusing around the RQ-180.

If the RQ-180 can prove itself operationally, the Air Force will have addressed its need for a high-altitude penetrator. The next big challenge in rebalancing the service's ISR fleet will be to define the future of the Predator and Reaper and their potential successors.

Where Does RQ-180 Fit In Stealthy UAS History?


ISR and other aerial support assets are not sexy unlike fighter planes (the last sexy American ISR platform was SR-71). But it is in these capabilities that help maintain America's dominance over the rest of the World. Notice also that this new aircraft is no longer aimed at the low tech skies over Afghanistan. This aircraft is aimed at advanced heavily defended air space.