The reports of the imminent demise of the venerable U-2 spyplane are proving to be greatly exaggerated.
Initially, USAF had planned to retire every one of these intelligence-surveillance-reconnaissance (ISR) aircraft no later than 2012. Now, the Air Force says it is firming up a new scheme that would keep the high-flying, Cold War-era U-2 aircraft in front-line service until 2014, at least.
This is not the result of sentimentality. USAF needs more time to bring to maturity the U-2’s designated successor—the new RQ-4 Global Hawk unmanned aerial vehicle.
“The technologies aren’t quite ready yet for Global Hawk to pick up the load,” explains Lt. Gen. David A. Deptula, Air Force deputy chief of staff for ISR.
One of 33 modernized U-2S reconnaissance aircraft over California.(Photo by Denny Lombard)
USAF once regarded the RQ-4 as a complement to U-2, said Brig. Gen. Robert P. Otto, commander of the 9th Reconnaissance Wing, Beale AFB, Calif., the unit that operates both airplanes. Then, said Otto, the cash-strapped service decided to retire the U-2 “once the Global Hawk meets our agreed capabilities.”
However, that is taking longer than anticipated. Thus, said Deptula, “we are modifying our high-altitude transition program.”
Deptula added that he had no real doubts that the RQ-4 eventually would replace the U-2 and shoulder all of the high-altitude reconnaissance mission, and believes only that it’s “going to be a bit longer than the current plan.”
Thus, the U-2 will be flying for quite a few years yet.
The U-2 and Global Hawk are often mentioned in the same breath. There is a common misperception that, except for the fact that the U-2 carries a human pilot and the Global Hawk does not, the two aircraft are virtually interchangeable. This is not so.
They both fly at very high altitudes. Both aircraft carry a variety of sensors. Yet the two machines are marked by major differences. Each has capabilities that the other lacks, and their ISR products do not completely overlap.
The U-2 can stay airborne for half a day at altitudes of around 70,000 feet. Its highly advanced sensors suck up electronic signals, electro-optical and infrared images, and high-resolution synthetic aperture radar pictures.
The Air Force has a total of 33 U-2 aircraft. The entire fleet has just undergone a lengthy series of upgrades comprising, among other things, installation of a new digital cockpit and new engines. These and other improvements have brought every U-2 up to the most advanced U-2S configuration.
The U-2’s main limitation is the endurance of the pilot. During the Cold War, typical missions lasted about nine hours and were strictly scripted. Aircraft rarely deviated from “the black line”—the planned route.
Over the past few years, though, missions have grown steadily longer, and now flights of more than 11 hours are not uncommon. This is a result of increased “dynamic taskings”: flight operations in which the pilot deviates from the flight plan to add additional, pop-up ISR targets to a mission.
The U-2’s unique feature is the optical bar camera sensor, which takes extremely fine-detail photos of broad swaths of terrain. This camera is a “wet” system that produces actual color film on rolls that are thousands of feet long. Once the rolls reach the ground, technicians process the film and then digitally scan it so that the images can be passed to commanders. It is stored for later search and comparison.
So voluminous are these data—measured in terabytes—that the information is put on discs for storage and transport; it would choke a Web server.
Meanwhile, non-film intelligence can be transmitted from the U-2 while it is still aloft, in near real time. It can, in a fast-moving situation, transmit directly to a joint terminal attack controller 13 miles below.
An RQ-4 Global Hawk is readied at Beale AFB, Calif.(USAF photo)
The Global Hawk is a different story. It emerged in the 1990s as a developmental system. There was immediate recognition that this aircraft offered unprecedented powers to maintain persistent, “staring” overwatch of a given area. It can cruise at about 60,000 feet, and remain airborne for 30 hours straight.
In the wake of the Sept. 11, 2001 attacks, the Air Force put the still-developmental RQ-4 to work over Afghanistan, and pressed for models with more versatility and power.
The current operational version is the RQ-4A—known as the Block 10. This UAV carries the Integrated Sensor Suite, which includes synthetic aperture radar and moving target indicator—not unlike the equipment of the E-8C Joint STARS—as well as a high-resolution electro-optical digital camera with an advanced infrared sensor.
Unlike the U-2, however, the RQ-4A’s optical field of view is narrow. In the words of one analyst, observing the battlespace with the RQ-4A is like “looking through a soda straw.”
USAF today flies a total of seven RQ-4A aircraft. Air Force plans call for flying these first models through 2011. They would then enter a replacement cycle, supplanted by the first of an eventual fleet of 70 RQ-4Bs.
The B variant will have more capabilities and provide the basis of Block 20, Block 30, and Block 40 upgrades.
The Air Force would buy these aircraft through the middle years of the 2010-19 decade.
The new airframe has a longer wingspan, thicker fuselage, and more powerful engine. The increased size offers a sensor payload 50 percent greater than that of the RQ-4A, and features better sensors with the ability to collect radar, EO/IR imagery, and signals intelligence all at once.
Flight testing of the Block 20 and development of sensor payloads for the Block 30 are under way. The RQ-4B will eventually carry the Air Force’s most sophisticated ground-mapping radar with moving target indication, the Multiplatform Radar Technology Insertion Program, or MP-RTIP.
The optical bar camera has many fans, particularly at the highest levels of government, because its wet film resolution is, as Otto noted, “still better than anything we can get through digital imagery,” which is all the RQ-4 takes.
Can the Air Force make the RQ-4 everything the U-2 is today
“Not necessarily, no,” said Deptula. “But then, the U-2 isn’t what the Global Hawk is.”
Deptula noted that the drone’s ability to stay aloft for 30 hours at a time and transmit products in near real time is highly valuable. So, while it’s not a one-for-one replacement, the RQ-4 brings capabilities that the U-2 simply doesn’t have.
A U-2 pilot—this one is Lt. Col. Eliot Ramey, 99th Reconnaissance Squadron commander—must be sealed in a spacesuit and then wedged into a tight cockpit for sorties that can last more than 11 hours.(Staff photo by John A.Tirpak)
Still in Fine Fettle
The Air Force is looking to UAVs to perform more missions where persistence offers value. Air Combat Command recently launched a broad analysis of alternatives on how UAVs can pick up additional roles traditionally handled by manned aircraft.
No particular technical problem would force the U-2 to the boneyard, according to Col. Stephen P. Sheehy, 9th Maintenance Group commander at Beale, which is responsible for both the U-2 and RQ-4.
While the U-2’s sensors do suffer from some “vanishing vendor” problems—in which some of the parts are no longer made—Sheehy said that’s typical throughout the Air Force, and is an issue for the Global Hawk as well. It’s “nothing we’ll ever get away from,” he said.
He went on to note that the U-2, “structurally, is in better condition” than some F-15s and F-16s in front-line service.
Studies carried out by Air Force Materiel Command and Lockheed Martin, the U-2 prime, say the airplane could soldier on for another 15 years or so. That is because its flight profile is relatively gentle—pilots can’t pull more than two Gs because of the long, fuel-laden wings—and it is usually “parked” at high altitudes, where buffeting is minimal.
Of Beale’s 33 U-2s, most are of 1980s vintage, though a handful date to 1968. “Flying, [you] can’t tell the difference,” Sheehy said.
Indeed, the real issue is the sensor package. How long does the Air Force want to keep funding hard-to-maintain systems that are of a type different from those on the RQ-4
At the 9th Wing, Otto noted, pilot training for the RQ-4 and U-2 has been largely merged. Student pilots for each aircraft “attend core academics together … and then they branch off” into their specific weapon systems. Some savings have been achieved by consolidating the schools.
The Navy flies early RQ-4As as demonstrators for its Broad Area Maritime Surveillance program, which will field RQ-4Bs. Navy UAV pilots also have trained at Beale. The Air Force and Navy are considering making this arrangement permanent.
Otto also believes the Air Force and Navy could save serious money by coordinating their RQ-4 and BAMS operations. On a recent deployment of RQ-4s to US Central Command, Beale sent the aircraft first to NAS Patuxent River, Md., and used the Navy’s BAMS equipment to land, service, and relaunch the RQ-4s from there.
Gen. Carrol H. Chandler, the commander of Pacific Air Forces, and Gen. Roger A. Brady, the commander of US Air Forces in Europe, have expressed interest in partnering with other countries on use of the RQ-4. Germany is buying the airplane; Australia, Canada, and South Korea have shown strong interest in doing so.
“I think there’s a lot of opportunity for synergy with the Navy … BAMS program, and I’m pushing for commonality of equipment so that Navy pilots and sensor operators could help us with our airframes and we could help them with theirs,” Otto asserted. Cooperation can make the overseas aircraft’s “footprint”—the people and equipment necessary to operate from a forward location—”as small as it can be,” he added.
Beale’s operators and maintainers have also learned a lot from nonstop deployments of the still-developmental RQ-4 to Southwest Asia. The first deployment to Guam, for example, required 26 maintainers and 11 pallets. The next one took just 12 maintainers and two pallets, along with some “modest prestationing of equipment” at the facility, Otto reported.
Capt. Stephen Mathews flies a practice RQ-4 mission using nothing but a keyboard and mouse, as Tim Burns, a contractor from Northrop Grumman, looks on.(Staff photo by John A. Tirpak)
The RQ-4 Global Hawk, as the product of an advanced concept technology demonstration, has at times been difficult to support, Otto acknowledged.
“We rushed the Global Hawk into service without shaking it out fully, without understanding the repair problems, and quite frankly, that’s [been] the Achilles’ heel of the Block 10,” he admitted. Support has been an issue “not so much for the airframe, but for the sensors.” Otto said there has never been enough test equipment to support both operations and the test program at once, and “we need to do better on that.”
The 9th Wing has put top priority on making sure a sufficient number of airplanes are available when the combatant commanders ask for them, and so have sometimes had to operate with less than enough airplanes for training, Otto said. Because RQ-4 is still a new system and not yet at maturity—indeed, initial operational test and evaluation will only get going this summer—there simply aren’t enough spare parts to go around.
Sheehy said that of the seven RQ-4 airplanes, three are always available for the combatant commander’s use. Two more fully operational aircraft are at Beale for pilot training, and, typically, the other two are not fully mission capable. One is likely to be flyable but incomplete due to a missing sensor part, and the other is usually being cannibalized. The parts are sent forward to the RQ-4’s combat operating location in the CENTCOM area of responsibility.
A comprehensive spare parts pipeline wasn’t created when RQ-4 was rushed from development to front-line service because the Air Force never intended to operate the system as anything other than a short-run stopgap. The parts problem should be addressed with the arrival of Block 20 and later versions.
To keep the combatant commander fully equipped, when it came time to do major repairs and maintenance on the initial RQ-4s, “we did a swap out,” Otto said. Beale-based airplanes were sent to CENTCOM, and the war-weary aircraft came home for service. If the aircraft had been kept in theater, they might have been out of action for “weeks, perhaps months.”
At 70,000 feet, the U-2 pilot gets a grandstand view of the curvature of the Earth. Radar and infrared sensors can cut through the clouds for a clear picture of the ground.(USAF photo)
Ramping Down U-2 PDM
Moreover, if most of the aircraft back at Beale are down for service issues, Otto said pilots will be sent forward and actually fly combat missions as part of their training program. An experienced instructor is always sitting next to the pilot, “and neither one of them is in harm’s way” if something goes wrong. The students get the most realistic training possible, and it adds to efficiency.
“What does the taxpayer want? They want effectiveness, and 75 percent of Global Hawk’s hours have been supporting combat operations. That’s a pretty good [measure] of effectiveness,” Otto said. The RQ-4 and similar UAVs offer “some opportunities as an Air Force to rethink some of the traditional notions” of where it is appropriate to conduct training.
Sheehy said one of the key factors in whether the U-2 could go on beyond 2014 is the contractor, Lockheed Martin.
Programmed depot maintenance on the U-2 is done at Lockheed Martin’s facilities. The Air Force does not have an organic capability to do this work.
Once PDM is stopped, Lockheed has said there’s no going back, Sheehy noted. The Air Force has already told Lockheed that it is ramping down U-2 PDM, and has slid from six aircraft per year to four. To go back up to five would be possible, but it would take months, Lockheed Martin officials told Sheehy.
However, Sheehy believes that Beale should be the central location doing RQ-4 maintenance and phase inspections.
With 30-hour endurance and thousands of miles of range, “you can fly anywhere in the world [and] back to Beale on one sortie,” he said. That makes more sense than setting up many repair locations wherever the aircraft is being based at the time, he asserted. He sees Beale as the worldwide “center of excellence” for RQ-4—for the Air Force, Navy, and foreign customers as well.
Based on nearly a decade of Air Force experience with the RQ-4, Sheehy doesn’t expect that the mainly composite aircraft will have any trouble lasting a long time.
“I think … Global Hawk will fly a lot longer than people expect. We have two aircraft past 5,000 hours, [and] a third approaching 5,000 hours, and they are still going strong.” The airplanes are performing well, he said, and the only issue is that the paint doesn’t stick to the composite fuselages very well. Northrop Grumman, he said, never expected to paint the airplanes, but Sheehy said paint is necessary to keep moisture from getting into the composite structure.
“Moisture is the ‘rust’ of a composite,” he said.
|Getting Up There, and Getting Down Here
U-2 pilots show up for a mission about two hours before becoming airborne. Because missions can last 12 hours, crew rest of 12 hours prior to a flight is carefully timed.
It takes just about five minutes for a U-2 pilot, assisted by life support technicians, to get sealed into the orange pressure suit that will keep him or her alive at extreme altitude. Once it’s airtight, the pilot must breathe 100 percent oxygen for at least an hour prior to becoming airborne. This practice helps prevent nitrogen bubbles in the blood from giving pilots “the bends” upon landing.
The U-2 pilot must also quaff large quantities of water, via a long straw snaked through a one-way flap in the helmet, to prevent the dehydration that comes with breathing pure oxygen.
To taxi, the pilot must keep the U-2 balanced on a set of bicycle landing gear. He or she is assisted on takeoff by “pogos,” detachable wheels that keep the fuel-laden wings off the ground. On takeoff, they fall away, and are collected and reused. The pilot can’t see the horizon once the U-2’s long nose is raised, so another U-2 pilot, chasing close by in a sports car, calls on the radio with observations of the aircraft’s attitude and condition.
The U-2 roars off the runway and ascends like a rocket, but will take up to an hour to reach cruising altitude, depending on how crowded the intervening airspace is.
On landing, the sports car again chases the U-2, the pilot inside calling out the number of feet until touchdown for the pilot in the cockpit. The airplane is flown to a total stall, so a second pair of eyes outside the airplane is crucial.
Once the aircraft has settled down, the U-2 pilot must work the rudders, ailerons, and throttle to keep the wingtips off the ground during taxi.
Finally off the runway, the pilot slowly allows one wingtip to touch the tarmac. Titanium skids on the bottom of the wingtip prevent damage, but the skids show barely any wear, such is the skill of the U-2 pilots.
The RQ-4 uses “split remote” operations. That means a Launch and Recovery Element gets the aircraft airborne and later lands it at the forward operating base. In between, it is flown remotely by pilots back at Beale, in the Mission Control Element. The aircraft is flown with keyboard and mouse; no joystick is involved. Flight status is displayed on one screen while mission and sensor information is displayed on others. This feed can be sent anywhere the operators wish to direct it.
Because the RQ-4 flies much of its mission autonomously, an exquisite series of communication links must be functioning properly before a launch can take place. The aircraft must have a solid connection to UHF, GPS, and Inmarsat satellites, and have a solid link to the LRE housed nearby in a transportable “shelter” (they’re not called “cockpits”) and the MCE at Beale.
Once given the go-ahead, the RQ-4 rolls on its own, almost magically following the yellow line on the taxiway, using a high-fidelity GPS signal. After it lines up on the runway, and after a last double-check of connections, the LRE releases the brakes and the aircraft accelerates to takeoff speed. Almost immediately after getting airborne, its engines become almost too quiet to hear. Indeed, they are hardly noticed in the traffic pattern above the base.
Once the aircraft is safely airborne and checked out, the MCE takes over the RQ-4. As automated as the craft is, a trained pilot is still needed to communicate with civil air traffic control and safely navigate controlled airspace as the RQ-4 ascends to its operating altitude. Even after years of operations, the Federal Aviation Administration has yet to grant permanent permission for RQ-4s to transit the skyways; waivers must be obtained on a weekly basis.
During the mission, the pilot sends the RQ-4 where it is to go, and the aircraft’s onboard processors decide how to get there, using engine and aileron inputs (the aircraft has no flaps). The sensor operator, seated next to the pilot, coordinates the combination of sensor activations needed, and passes the data in near real time to whoever has requested it.
Pilots and sensor operators fly their own “black line” but likewise deviate at the request of the air operations center to respond to urgent calls from troops in contact to provide signals and imagery information. It can overlay this information, providing the first true near-real-time hyperspectral image.