Science Projects

Dec. 1, 2003

The US Air Force and its organizational forebears have been the driving forces of aviation technology almost since the day the Wright Flyer changed the world at Kitty Hawk.

Early in the 20th century, Army units carried out extensive experiments with what was then the cutting edge of flight—early Wright aircraft models. Today, USAF organizations are hard at work on airborne lasers, unmanned aerial vehicles, and other potentially revolutionary 21st century systems.

Air Force research has contributed significantly to both military and civilian aerospace capabilities. A day-long symposium sponsored by the Air Force’s chief scientist, Alexander H. Levis, and the Air Force Association at this fall’s AFA National Convention in Washington, D.C., highlighted this impact by putting some of the service’s most important developments in a historical perspective.

Among the general principles that a study of Air Force science and technology reveals is that it takes a long time for important ideas to develop, said Levis in his opening remarks to the symposium.

The projects that now occupy Air Force researchers will “benefit warfighters 20 years from now,” he said.

As with other advances in modern science, important Air Force breakthroughs typically have not depended on a single “Eureka!” moment experienced by one person. They are more like a mosaic, comprising many small gains made by numerous individuals.

While the amount of funding for a project is important, that funding’s consistency is even more important. Large up and down swings in support are destructive, said Levis.

Nor do the most useful capabilities spring pristine from researchers’ imaginations. Many of today’s key systems, such as the Airborne Warning and Control System, are now being used for missions that are beyond what was originally intended. In fact, the consensus of the symposium presenters was that the best results occur when warfighters are included in the development process.

The GPS Revolution

The Global Positioning System is a good example of the lengthy—and bumpy—road that many important Air Force technologies travel before deployment.

GPS was not in fact the first US military satellite-based navigation system, noted Michael I. Yarymovych, former Air Force chief scientist. It was preceded by a Navy system, Transit, which was developed in the early 1960s to provide positional information for the then-new nuclear submarine fleet.

Transit provided accuracy within 83 feet. But it could provide positions in only two dimensions and worked only if the Navy vessel attempting to use it was moving very slowly. “You had to be almost stationary” to use Transit, said Yarymovych.

By the late 1960s, the Pentagon was funding a number of development programs meant to address these problems, including an upgraded Transit and an Air Force research effort, dubbed USAF’s System 621B.

The 621B program contained a number of visionary aspects, including a proposed use of satellites in “eggbeater” orbits to provide continuous coverage. Yet, in a clash of budgetary and programmatic priorities, 621B was canceled by Pentagon officials in August 1973. “I went down on bended knee and pleaded, ‘Let’s give this thing another chance,’ ” Yarymovych told symposium attendees.

A crash effort by a small group of Air Force officers yielded a refurbished proposal and Pentagon approval in December 1973. Yarymovych noted that, at the time, the term “satellite system” was considered a turnoff, so when the group cast about for a new name they decided to emphasize that the new effort was aimed at a positioning system and a global one at that.

“GPS was the new name and that turned out to be a winner,” said Yarymovych. However, it would be decades later, in 1994, before GPS was declared fully operational.

To say it was a hit with the military is an understatement. In 1991, before the system’s complete deployment, only a very small percentage of munitions dropped in Desert Storm were GPS-guided. By 2003 in Operation Iraqi Freedom, 70 percent of the munitions dropped were guided—mainly by GPS. Positional information beamed from GPS “birds” guided everything from small groups of special operations forces on the ground to most air refuelings.

Yarymovych said that Iraq had some Russian-built jammers that might have posed a problem for GPS. “Fortunately they didn’t have any Russians helping them,” he added.

GPS designers were not surprised by the system’s acceptance in the military, and Yarymovych predicted that, within the next five years, virtually all military systems will be dependent on GPS. What did amaze the system’s architects was the rapid ascendancy of GPS in the civilian world. Today, the number of GPS sets in civilian hands is rising by 200,000 a month. Current predictions estimate there will be more than 50 million civilian users by 2010.

Creative ideas for use of GPS data are myriad. At Stanford, for instance, some students hooked a robot tractor up to a GPS receiver for auto-plowing. The worst tracking error the tractor made? Three inches. Within a few years, every car, every ship, and half of all farm vehicles will have GPS capability, said Yarymovych. And scientists will use GPS to track shifts in crustal plates to help them predict earthquakes.

Today, GPS needs improvements in robustness. There is also a challenger—Europe’s Galileo system—to its status as a world standard, but, to this point, the success of GPS is unquestioned.

“Here is a system that started in the ’60s … and, by 2000, revolutionized military operations and the world,” said Yarymovych.

The Precision Hunt

Perhaps no area of military operations was revolutionized more than delivery of munitions. The introduction of GPS, laser guidance, and associated targeting systems has given USAF a precision bombing capability undreamed of by service pioneers.

“In World War II, we put a quarter on the map and drew a circle around it and hoped to hit it,” said Lt. Gen. William T. Hobbins, USAF deputy chief of staff for warfighting integration. “Today, we put a quarter on the ground and hope to hit it.”

Initiatives to increase the effectiveness and accuracy of bombing date almost from the beginning of air warfare. By the end of World War I, the Navy was working with a “guided” system named the Sperry Aerial Torpedo. Army Air Services had the Kettering “Bug,” an unmanned aircraft whose engine shut down after a set number of revolutions, causing the wings to collapse and the explosive-laden vehicle to plunge to earth in the vicinity of a preselected target.

During World War II, it still took delivery of thousands of bombs to achieve a hit probability of 90 percent. But, by then, the US was funding some 15 programs meant to result in some form of munition with terminal guidance.

“There was a lot going on in World War II with respect to guided weapons,” said Robert P. White, historian for the Air Force Office of Scientific Research.

Some of this research culminated in the VB-13 Tarzon, a 12,000-pound, radio-guided bomb that was so big it could only be carried semirecessed on B-29 bombers. Technical and safety problems eventually led the Air Force to withdraw Tarzon from service but not before it was credited with destroying six targets during the Korean War.

By 1959, Bullpup, the first air-to-surface guided missile to be produced in quantity, had reached full deployment. It was less than ideal. Pilots deploying the radio-guided Bullpup essentially had to remain in sight of the weapon—exposed to enemy fire—as they steered it toward its target.

These relatively simple systems were followed by the Paveway series of laser guided bombs, which drew on basic research carried out decades previously. “You have to go back 20 to 30 years to see the pedigree in many of these weapons systems,” said White.

While the LGBs were a vast improvement over the earlier precision systems, it was the advent of GPS that gave precision guidance a giant boost forward. Bad weather and smoke became irrelevant, and the Air Force gained true fire-and-forget capability.

“All this arrives ultimately at JDAM,” said White. The Joint Direct Attack Munition is considered today’s gold standard of guided weapons. (See “Precision: The Next Generation,” November, p. 44.)

Basic research continues to add to existing systems—a new algorithm has improved JDAM accuracy, for instance. New technology is driving miniaturized systems that might not even have to explode to accomplish their mission. They could be corrosive, perhaps, or electronically debilitating.

The Sensor Path

The 1950s spawned innovations that led to remote sensing systems to improve detection, identification, and tracking of targets. For instance, electro-optical/infrared (EO/IR) imaging technology has been employed over the past 50 years on various platforms—each requiring different designs but all sharing basic technical parameters and components.

The most common application for EO/IR imaging systems is in air-to-air missile seekers, said Edward A. Watson, a technical advisor with the Air Force Research Laboratory. He said today’s missiles are using third generation EO/IR technology.

That technology now has gained additional importance in its use on unmanned aerial vehicles. The ability of UAV sensors to provide streaming video literally has “changed the rules of the game,” said Lt. Col. Steve Luxion, commander of the 17th Reconnaissance Squadron, Nellis AFB, Nev.

USAF’s Predator UAV proved its worth in Operation Allied Force over Kosovo, where it was used to track everything from tanks to Serbian troops hidden in Red Cross vans. The President himself viewed Predator video as part of his intelligence briefings. At the time, the system was still under development.

Near the end of the Kosovo conflict, Gen. John P. Jumper, then commander, Allied Air Forces in Central Europe, and now USAF Chief of Staff, had Predator armed with Hellfire missiles—a move Luxion called a “natural evolution.” Armed Predators were used in both Afghanistan and Iraq, destroying some high-value targets of opportunity.

During Operation Anaconda in Afghanistan, operators from Luxion’s unit directed Predators to help protect US troops pinned down by enemy fire. Luxion said that one dubious forward air controller, communicating directly with a Predator pilot, asked him to fire a missile at a rock to prove the UAV’s accuracy. After doing so to the FAC’s satisfaction, Predators actively engaged in the fight.

Luxion believes the US currently is only in the World War I or World War II stage of UAV development. “We’re just at the start of it,” he said.

While the remote sensing systems have continued to revolutionize airpower over the past 50 years, there are new wonders in the making. Watson said that the future likely will see active remote sensing using lasers. “They’ll use lasers as more than illumination,” he said.

The Vertical Advantage

It has long been a cardinal principle of warfare that the advantage belongs to the one who can see farther and better. Development of radar and sensor technologies has enabled the Air Force to seize that “vertical” advantage in one of its most effective uses to date: airborne remote sensing for command and control.

Airborne C2—one of the service’s greatest strengths—grew out of early air radar systems, one of the first of which was the EC-121 Warning Star. A derivative of Lockheed’s Constellation airliner, the Warning Star was originally used, beginning in 1953, as a radar picket line to buttress continental US strategic early warning systems.

Later, USAF employed it in ways its developers never envisioned—tracking material flowing down the Ho Chi Minh Trail in Vietnam. On Oct. 24, 1967, an EC-121 helped guide a US fighter into position over the Gulf of Tonkin to destroy a MiG-21. It was the first instance in which an airborne radar aircraft directed a successful air-to-air attack.

However, the EC-121 had two major flaws: radar clutter and reliability. “By and large, the Air Force remained unhappy with it,” said Thomas W. Thompson, head of the Office of History, Air Force Research Laboratory. It would be 1967, though, before work started on the E-3 Airborne Warning and Control System, today’s premier command, control, and communications platform.

Another present day system that grew out of operator frustrations during the Vietnam War is the E-8 Joint Surveillance Target Attack Radar System. During the war, the Air Force was stymied by its inability to destroy surface-to-air missile sites, so the service began work on the radar program that would later morph into Joint STARS.

“It’s interesting how many times an operator or someone working with an operator envisioned the future,” said Thompson.

Not that operators always see the future whole, according to retired Lt. Gen. Bruce K. Brown, former commander, Alaskan Air Command. Like the EC-121, AWACS was originally intended for strategic defense against incoming Soviet bombers. “[Tactical Air Command] wanted nothing to do with it,” said Brown.

Then, a 1976 air defense exercise changed everything. AWACS intercepted 199 of 200 incoming targets (“I still don’t know how that sumbitch got away,” recalled Brown), and suddenly TAC generals embraced the AWACS concept. Today, virtually all US air operations rely on AWACS control.

Brown expressed concern that it takes “20 years to bring technology to bear.” He advocates pushing technology ahead of defined operational need. In his words, “The notion that we need to tie technology to useful military applications is nonsense.”

The Laser Revolution

Directed energy is a technology that has taken a long time to develop, but, after years of work, it may now be poised on the edge of success. “We expect some rather dramatic things to occur in the next decade or so,” said retired Maj. Gen. Donald L. Lamberson, who worked on directed energy programs in the 1980s.

Lasers were discovered in May 1960 and were soon scaled up to high-power instruments. The potential of a beam of energy traveling at the speed of light immediately attracted the attention of Pentagon leaders, who envisioned a new class of weapons that would revolutionize warfare.

“Lasers were revolutionary,” said Robert W. Duffner, historian at the Air Force Research Laboratory’s Historical Information Office at Kirtland AFB, N.M. Lasers lent themselves to precision engagement with targets, and their effects could be tightly controlled.

Duffner noted that the name of one early laser research effort was Project Eight Card, a poker reference meant to symbolize the edge lasers might give the US over Soviet forces. Such early work eventually led to the Airborne Laser Laboratory (ALL), which served as a technological bridge between lab research and the current Airborne Laser (ABL) program.

“I look at the [ALL] as the Wright Flyer of the laser world,” said Duffner.

In a 1973 experiment, an Air Force laser shot down a drone. In 1983, another destroyed a missile in flight. Along the way, Air Force labs have produced a number of new and improved technologies, such as the chemical-oxygen iodine laser and sophisticated adaptive optics that are critical to the ABL system.

The ABL platform—a modified Boeing 747—is now at Edwards AFB, Calif., having control systems installed. Plans call for the entire ABL system to be integrated next summer. Lamberson credited uncooled laser optics developed for the Strategic Defense Initiative as being a “big, big help” in ABL development.

“Directed energy weapons will be the centerpiece of the 21st century Air Force,” said Lamberson. “They are totally synergistic with precision guided weapons.”

One of a Kind

The now retired SR-71 Blackbird reconnaissance aircraft is a prime example of the blending of human and weapons systems research and development. Without the early work of human systems researchers in life-support technologies, manned flight at Mach 3 and 80,000 feet would have been impossible.

“There are lots of [human systems research] challenges still out there today,” retired Col. Joseph W. Kittinger Jr. told symposium attendees. Kittinger, as a young officer, did a series of experimental free jumps from altitudes of 76,000 to 103,000 feet. Among other things, these death-defying jumps helped researchers understand how to eject at supersonic speeds—since Kittinger himself went supersonic on the way down.

Retired Maj. Gen. Robert F. Behler, a former SR-71 pilot, said that the most dangerous part of flying the Blackbird was the training involved. In particular, he recalled being dropped in water in a full-pressure suit.

Behler also noted that the SR-71 ejection capsule contained only 15 minutes of oxygen, yet, from high altitude, the capsule took 12 minutes to come down. “In training, they always told us to try and not hyperventilate,” he said.

The SR-71 remains one of the physically most impressive airplanes ever designed. It flew so fast that the heat of atmospheric friction caused the aircraft to significantly expand in the air. This USAF technological marvel played an important role in US foreign policy. One example, said Behler, was the 1984 Nicaragua standoff.

In October 1984, US intelligence reported that Soviet MiG-21 fighters were being shipped in crates on a Bulgarian freighter bound for Managua, Nicaragua. US officials did not want such relatively modern fighters delivered into the hands of Nicaragua’s Sandinista rulers. Behler said he made several reconnaissance trips, flying out of Beale AFB, Calif., to Nicaragua and back. The SR-71’s sonic boom put the Sandinistas on notice. The crates remained on the freighter.

“The bottom line was, we were saying, ‘We are watching and there is nothing you can do about it,’ ” said Behler, adding, “It was an honor to fly that aircraft.”

Indispensable Satcom

Military satellite communications evolved from a paper concept in 1945 to the sophisticated systems that are the linchpin of modern US military operations.

“Everything we have done [in recent years] wouldn’t be possible without satellite communications,” said Harry L. Van Trees, a pioneer in the field and who is currently a professor of electrical engineering and director of the C3I center at George Mason University in Fairfax, Va.

Satcom developments in the commercial sector in the late 1950s and early 1960s aided initial military efforts. The first military capability came in the form of the Super High Frequency Defense Satellite Communications System, launched in 1966.

The Extremely High Frequency Milstar system, first launched in 1994, provided a transition from relays to networking in space. Networking “meant you could get guaranteed command and control for nukes,” said Van Trees. “That’s what Milstar was designed to do.”

Military satcom capability continued to evolve, often still taking advantage of commercial developments. For instance, Van Trees noted that although the Iridium satellite communications system was a commercial flop for its developer Motorola, it became a crucial adjunct to military satcom. By the time Iridium’s satellite constellation was in place, its satellite-based phone service—employing big 14-ounce handsets that needed to be near a window to work—had been supplanted in most of the developed world by cellular phone service.

Motorola’s loss was the military’s gain. As Van Trees pointed out, “There isn’t ground-based cellular in many of the places the government wants to go.”

The Pentagon also developed its Global Broadcast System initially using leased commercial satellites.

All this communications capability, and more, came together in Operation Iraqi Freedom. DSCS provided an enormous amount of bandwidth. Milstar enabled secure command communications. Ultra High Frequency satellites were used to direct the strike against a house where Saddam Hussein was reportedly located. GBS was used for Predator UAV control, and Iridium was crucial for special operations teams—in some cases, it was their only means of communication.

Peter Grier, a Washington, D.C., editor for the Christian Science Monitor, is a longtime defense correspondent and a contributing editor to Air Force Magazine. His most recent article, “Lighter Footprint, Longer Reach,” appeared in the October issue.