Many defense analysts argue that the nature of warfare and the way the United States will fight future wars are undergoing a fundamental transformation. They contend that the development of new technologies (such as stealthy aircraft, highly accurate precision munitions, and improved sensors for detecting, tracking, and identifying enemy forces) will work together to allow a force to dominate the battlefield completely--more so than has been achieved in the past, even during the Persian Gulf War. In short, that revolution in military affairs means having a monopoly on information about the battlefield, as well as the ability to attack and destroy an enemy while denying it the same capability.

The armed services have long had many different ways to collect battlefield intelligence. The scout on foot is probably the earliest example. Today, the U.S. military also uses sensors that are mounted on a variety of satellites, manned aircraft, helicopters, and ground vehicles to collect information. In the future, it also hopes to make greater use of unmanned aerial vehicles (UAVs) to carry sensors.

UAVs, which have sometimes been referred to as drones, are relatively small aircraft that can be preprogrammed or operated by remote control. Many defense analysts view them as crucial to the success of the revolution in military affairs. In the course of one mission, a UAV can find, identify, and even direct a precision munition to a target--and then assess the damage done to that target after the munition has hit--without risking the lives of an aircrew. UAVs are also appealing to the military because different UAV systems can collect different types of information, such as tactical (or battlefield) intelligence and strategic (or longer-range) intelligence. In addition, UAVs may be able to perform such roles as relaying messages during a battle, locating or jamming enemy radar, or monitoring areas during peacekeeping missions.

The services are developing and plan to procure four new UAV systems: Predator, Darkstar, Global Hawk, and Outrider (see Table 1). Those programs, if ultimately successfully, promise to give battlefield commanders a valuable new reconnaissance capability as well as to enhance and perhaps eventually replace many sophisticated manned reconnaissance systems that provide intelligence to theater commanders and the national command authority (the President and the Secretary of Defense).
 

Although the Congress generally supports UAV technology, it has expressed concern at the proliferation of UAV programs--particularly in light of their troubled technological history and the seeming inability of the Department of Defense (DoD) to develop and field a major UAV system. In analyzing DoD's current programs, the Congressional Budget Office (CBO) has identified three key areas of concern. They are the suitability of some new UAVs for their intended missions, apparent overlaps in capability among different systems, and uncertainty about who will control UAVs on the battlefield.
 

A BRIEF HISTORY OF UAVs

UAVs, in one form or another, have had a checkered history in the U.S. military. Although the notion of using unmanned aircraft has been around since World War I, the United States did not begin seriously experimenting with unmanned reconnaissance drones until the late 1950s. That initial effort proved unsuccessful. Later, the Vietnam War and the Cold War spurred a variety of development programs, which led to several reconnaissance drones, such as the Firefly and Lightning Bug. Although those early UAVs were sometimes difficult to operate and maintain, the Air Force deployed them for a variety of missions, including gathering signals intelligence and collecting high- and low-altitude imagery both during the day and at night. By the end of the Vietnam War, concern about casualties meant that only two aircraft were allowed to fly reconnaissance missions over North Vietnam: the Lightning Bug UAV and a high-altitude, manned reconnaissance plane (the supersonic SR-71).

The urgent need for unmanned aerial vehicles ended with the Vietnam War, but the services remained interested in exploring the capabilities that those aircraft had to offer. In particular, the Army began developing a tactical UAV called Aquila in 1979. It suffered many growing pains (developmental problems, cost overruns, changes in requirements) and was finally canceled in 1987. During that time, the Israelis used very simple and cheap drones to good effect to destroy Syrian air defenses in Lebanon's Bekaa Valley in 1982. Their success inspired then Secretary of the Navy John Lehman to push for his service to acquire UAVs, primarily to support targeting by, and conduct battle-damage assessment for, U.S. battleships. His efforts led the Navy and Marine Corps to acquire nine Pioneer UAV systems, which are still in use today. Those systems have been employed in many U.S. operations since the 1980s, including the Gulf War and Bosnia. In addition, the armed forces, particularly the Marine Corps, have used some very small UAVs, such as the Exdrone, in both operations and training.

In recent years, the Pentagon has started a number of other UAV development programs. Two of them--Medium Range and Hunter--were ultimately canceled. Another UAV, Predator, is now being acquired by the Air Force. And three others--Darkstar, Global Hawk, and Outrider--are still in development. DoD officials appear more optimistic about this group of UAVs than about earlier ones, partly because advances in technologies such as miniaturization make developing UAVs easier, and partly because the developers now have more experience in integrating all of the components that compose a UAV system (such as the air vehicle, ground support equipment, sensors or other payloads, and communications equipment).
 

THE ROLE OF UAVs IN FUTURE WARFARE

When DoD or the services attempt to envision the future of warfare, UAVs play an important role in their vision. One of the central concepts in predictions about future warfare is the so-called revolution in military affairs. That term describes a group of technologies (long-range precision munitions; stealthy aircraft "platforms"; real-time, all-weather, day-and-night reconnaissance and targeting; and integration of command and control among the services) that, once combined, produce a major leap in a unit's fighting power. The revolution in military affairs also includes innovations in strategy, operations, and tactics, which in turn are reflected in the training programs of the services. For example, one priority of that revolution is being able to mass fire from widely dispersed forces to have a concentrated effect on one location. Achieving that requires having improved reconnaissance, communications, and precision-strike capabilities, as well as new tactics that must be incorporated into training programs.

The official vision statement of the Joint Chiefs of Staff, Joint Vision 2010, fully embraces the revolution in military affairs. A crucial component of Joint Vision 2010 is the importance of information superiority--the ability to collect, process, and disseminate an uninterrupted flow of information while exploiting or denying an enemy's ability to do the same. UAVs are likely to be crucial in achieving information superiority, particularly because they can collect information that in the past would have been difficult to acquire without risking the lives of personnel. Although the text of Joint Vision 2010 is not specific about which weapon systems and platforms should form the future force, the graphics that accompany the report give a prominent place to unmanned aerial vehicles.

DoD's Integrated Airborne Reconnaissance Strategy also recognizes and incorporates UAVs. That strategy examines the future reconnaissance needs of the services, the technologies and platforms necessary to meet those needs, and ways to integrate those technologies so they are more cost-effective and can be operated by a variety of DoD's warfighting elements. Over the long run, the strategy expects UAVs to provide wide-area surveillance and continuous coverage at the strategic level and possibly replace manned tactical reconnaissance altogether. In addition, unmanned aerial vehicles are expected to give national decisionmakers greater willingness to accept the risks normally associated with airborne reconnaissance. That does not necessarily mean that UAVs will survive better in high-threat environments than manned systems, but that they can be risked without endangering the lives of aircrews.

Vision statements or studies by the various services also include an important role for unmanned aerial vehicles. For example, the Navy's littoral (coastal) warfare strategy, Forward . . . From the Sea, and the Marines Corps's concept of operational maneuver from the sea incorporate UAVs to provide timely reconnaissance on the prospective enemy forces that an amphibious task force may confront. They suggest that UAVs may also be able to provide targeting information to long-range precision weapons and then follow up with battle-damage assessments of those targets. Similarly, studies by the Air Force's Scientific Advisory Board and DoD's Defense Science Board have envisioned a central role for UAVs in future combat operations.

The Potential Missions of Unmanned Aerial Vehicles

Defense planners expect UAVs to perform a variety of specific missions, many of which fall into the broad category of reconnaissance and surveillance. Those missions exclude the more advanced concepts that are sometimes discussed of using UAVs directly as combat vehicles.⁽¹⁾ Such ideas are just beginning to be developed and are beyond the scope of this analysis.

The missions that UAVs can perform fall into two general categories of intelligence: tactical and strategic. Tactical intelligence refers to information collected for the local area of operations. For example, a brigade commander whose unit is responsible for seizing the ground in his area of operations will want to know the size, quality, and disposition of any enemy forces in that area. In the past, a brigade commander usually had to rely on troops or manned aircraft, such as helicopters, to scout that terrain and relay the information back to him. But a UAV designed to support such a commander could provide him with nearly instantaneous (or near-real-time) video, day or night, of the terrain "just over the hill" without risking pilots or scouts. That, the Army stresses, is a capability brigade commanders have never had before. Furthermore, the tactical UAVs now under development should be able to provide surveillance for a much longer time before requiring relief than a manned platform can.

A good illustration of that capability was provided during the Army's Task Force XXI Advanced Warfighting Experiment at the National Training Center in Fort Irwin, California. The Army praised the tactical UAV involved in the war game (Hunter) for greatly aiding the commander of the task force. According to the Army, Hunter's presence caused the opposing commander to spend an extraordinary amount of time protecting his own force and thus made it difficult for him to assemble that force for an attack.⁽²⁾

In contrast to tactical intelligence, strategic intelligence refers to the type of longer-range information collected by reconnaissance satellites and manned U-2 aircraft. It can include information about another country's military assets, such as the concentration of its forces, weapons of mass destruction, and industrial and manufacturing facilities. Some of the UAVs under development are designed to provide that type of information. The most capable ones could monitor a particular area for more than 24 hours at a time--longer than an orbiting satellite can and without the risks of manned reconnaissance flights.

Reconnaissance and Surveillance. Although some people use the terms "reconnaissance" and "surveillance" interchangeably, this analysis makes a distinction between the two. Reconnaissance refers to obtaining information about the activities or resources of an enemy (or potential enemy) or collecting data about the meteorological, hydrographic, or geographic characteristics of a particular area. Unmanned aerial vehicles can perform that mission, although the size of the area they can cover will be different for different types of UAVs. For example, a wide-area search collector, such as Global Hawk, will be able to cover dramatically greater expanses than a small tactical UAV, but both are capable of searching for enemy forces.

Surveillance, by contrast, refers to watching a particular site or road or target for an extended period of time. For example, other sources of intelligence may identify a building as a possible hiding place for weapons (such as mobile ballistic missiles) but may not be certain that that is the case. A UAV, particularly one with a relatively long operating period (or "endurance"), can watch the building and observe whether mobile missiles arrive or depart. Or it may confirm, because of other activity, that the building is not a storage facility. According to DoD officials, the Air Force's Predator UAV has been used several times to follow a particular vehicle along a road for an extended period. At the end of the trip, the vehicle--in this case, a military truck--entered a building that was not known to be a facility for housing or hiding weapons. Through the imagery provided by the UAV, intelligence officers were able to determine that it was such a facility.

Another important surveillance role that unmanned aerial vehicles can play is in peacekeeping operations. For example, if a neutral zone could not be patrolled by peacekeepers on the ground (perhaps because of difficult terrain), a long-endurance UAV could watch the zone for violations. If several UAVs were available, the commander of a peacekeeping operation could conceivably have continuous video coverage of a disputed, demilitarized area. Predator successfully performed some similar functions during peacekeeping operations in Bosnia.

Target Acquisition. A principal mission of unmanned aerial vehicles is target acquisition--that is, detecting, locating, and identifying a particular target. A wide-area search aircraft, such as the Joint Surveillance Target Attack Radar System (JSTARS), might identify a group of moving vehicles in a particular area. A UAV could then be directed to that location to confirm, for example, whether the vehicles were tanks and, if so, whose they were. The UAV could also relay fairly precise location information so the vehicles could be attacked.

Target Designation. Some tactical unmanned aerial vehicles have both the power and payload capacity to carry a laser target designator. That device aims a laser at a target, such as a tank, so another platform can attack it with a precision munition. The Army has conducted at least four successful tests in which a Hunter UAV mounted with a laser designated a target, and another aircraft, such as a Kiowa Warrior helicopter, launched a Hellfire missile and destroyed the target.

Communications Relay. An unmanned aerial vehicle can also serve as a communications relay platform. In battle, forces may move quickly and exceed the range of their communications system, as happened during the Gulf War.⁽³⁾ A communications relay carried on board a UAV might be able to bridge the gap between the leading edge of a U.S. advance and higher-echelon commanders located farther back. Similarly, even in cases in which communications systems use satellites to give them longer range, UAVs could perform the same relay role as a satellite if the latter became overwhelmed with traffic or was damaged. Global Hawk has a far greater range, payload, and speed than any other planned UAV, so it probably has the most potential to substitute for or supplement satellites.

Battle-Damage Assessment. The original mission for which the Navy acquired UAVs in the 1980s was to assess the damage inflicted by its weapons. Specifically, the Navy bought Pioneer in part because it determined that long-range fire from battleships could be much more effective and precise if a UAV was watching the target area. The UAV substituted for a human forward observer to give gunnery crews direct imagery about how close a salvo came to hitting the target and what corrections were needed to strike precisely. Even though battleships have been retired, UAVs can perform the same mission over targets being attacked by aircraft, missiles, or other ships.

Communications and Electronics Intelligence. The Department of Defense conducted tests of a communications intelligence payload on board a Hunter UAV in November 1996. The primary purpose of such a payload is to locate and identify an enemy force's ground communications emitters, such as radio transmitters. In some cases, that can lead to detecting and identifying the locations of the enemy's military leaders as they communicate with their forces.

At the same time, DoD also tested an electronics intelligence payload on board Hunter that was designed to find and identify an enemy's ground radar emitters. Doing that successfully can enable U.S. forces to attack and destroy those installations early in a conflict, bringing serious harm to the enemy's air-defense network.⁽⁴⁾

Jamming. Besides locating enemy communications or radars, UAVs could be used to jam them. DoD has also tested payloads on Hunter that have employed a radar jammer or communications jammer.

Chemical and Biological Warfare Detection. Unmanned aerial vehicles are well suited to detect and determine the lethality of environments that are contaminated by chemical or biological agents. Using specialized payloads, UAVs can sample different layers of air over an area suspected of contamination without risking the lives of soldiers.

How Would UAVs Affect a Battle?

Once the currently planned reconnaissance UAVs are finished and deployed with U.S. forces, what difference will they make? The most obvious answer is that their widespread use will almost certainly save lives. If nothing else, risky reconnaissance missions that in the past were performed by manned aircraft or scout units could now be performed by unmanned aerial vehicles. Those missions include normal reconnaissance operations that are at risk from enemy fire as well as missions in environments contaminated by nuclear, chemical, or biological weapons.

Beyond that, how much difference UAVs will make to the success of a battle varies with the capabilities and response of the opponent. For example, few unmanned aerial vehicles were used during the Gulf War. More widespread use in that conflict would probably have made very little difference to the outcome because the war was so one-sided--both because of U.S. skill, strategy, and weapons and because of mistakes by the Iraqi army.

More insight can be gained from the Army's Advanced Warfighting Experiment at the National Training Center. In those exercises, the training units, which were equipped with UAVs, gained an advantage over the permanently based opposition force (OPFOR), which usually wins the "battles" at the training center. The commanders of both the opposition force and the units training there attributed a high military value to UAVs. According to some Army officials, the opposition-force commander became so concerned about destroying the UAVs that he changed his tactics and thus created opportunities for other systems to be more effective than they would otherwise have been. If those exercises are any guide, when unmanned aerial vehicles are used against a force that is not similarly equipped, they can enable military commanders to observe the enemy, identify its location and targets, and thereby disrupt its strategy--whether offensive or defensive--before that strategy can be carried out.

A more difficult question to answer--and one that has been asked in Congressional hearings--is, what would happen if both the United States and its opponent in some future conflict were similarly equipped with unmanned aerial vehicles? Assuming that both sides' commanders were intelligent and capable and both had UAVs, the presence of those vehicles would make little difference. The outcome would again depend on which side had the better-led, better-equipped forces--just as if both sides did not have UAVs. At the National Training Center, opposition-force commanders have asked for their own UAVs in future exercises to balance the battlefield. Exercises in which both sides operate unmanned aerial vehicles may provide some answers to that question.
 

DoD'S UAV PROGRAMS

As a practical matter, the Pentagon has decided that one type of UAV is not enough to provide imagery at all of the necessary levels. For example, the reconnaissance needs of a brigade commander, who controls a few thousand soldiers, are very different from those of the theater commander, who is in charge of the entire area of operations. The former needs to know what is a few kilometers away (or even just over the next hill), and television video is probably the most useful imagery to convey that information. The theater commander is concerned with a much larger number of issues, over a much wider area, and thus requires a much more capable and flexible platform for collecting intelligence.

Because of those different needs, the Department of Defense is developing a family of unmanned aerial vehicles to meet the multiple imagery requirements of the various services. One UAV (Pioneer) is already deployed; another (Hunter) was canceled after initial production, but the remaining systems are used in some training exercises. Predator has moved from the development stage to low-rate initial production for the Air Force. Three other UAVs (Darkstar, Global Hawk, and Outrider) are still being developed.

Pioneer

Pioneer has provided the Navy and Marine Corps with UAV capability since 1986.⁽⁵⁾ It was first acquired to support targeting by the 16-inch guns on board battleships that the Navy had brought back into service. After those ships were retired, the Navy and Marines kept the Pioneer systems to provide near-real-time reconnaissance, surveillance, target acquisition, battle-damage assessment, and battle management in both day and night operations. Pioneer can carry a 75-pound payload and provide five hours of endurance at a range of 185 kilometers (see Table 2). It uses a line-of-sight communications and data link, meaning that the UAV cannot operate over the horizon and still communicate with its controllers.
 

Both the Navy and Marine Corps consider Pioneer an outmoded system, however, and are anticipating its eventual replacement by either the Outrider tactical UAV or some other, as yet undetermined, system. In the meantime, Pioneer's service life has been extended several times. Currently, the last Pioneer is expected to retire in 2003, but the Navy and Marine Corps are considering retaining Pioneers until 2005 or 2008--probably as a result of the development problems that Outrider is experiencing and the Navy's desire to have a UAV with a heavy-fuel engine and a vertical take-off and landing capability.

While awaiting a successor, the Navy and DoD are making a number of upgrades to Pioneer to extend its service life to at least 2003. One involves integrating Pioneer with the common automatic recovery system, a technology (both hardware and software) that will allow the air vehicle to land automatically, thus increasing safety and reducing mishaps. Other enhancements include improving its ability to tap into the Global Positioning System, integrating Pioneer with the tactical control system (itself under development) that is designed to enhance the interoperability of UAV systems and their controllers, and incorporating a common tactical data link for the same purpose. Further upgrades to improve Pioneer's reliability are being considered. Modifications to enhance the capability of the air vehicle--such as a redesigned wing to double its endurance--are also possible, but they are currently restricted by a DoD policy that permits only reliability upgrades.

Hunter

The Hunter unmanned aerial vehicle grew out of the operational requirements document for the Short Range UAV system that DoD published in 1992. That document specified a military requirement for a tactical UAV with a radius of about 200 kilometers and endurance of eight to 12 hours that would provide imagery to commanders of corps, divisions, and task forces. Hunter was specifically designed to meet those requirements. It has a radius of 267 kilometers and an endurance at that radius of about 11 hours. It can carry roughly 200 pounds and provide imagery in both day and night operations.

Problems in Hunter's development, however, led to its early demise. Three crashes in 45 days, as well as its inability to meet some of its performance criteria, led the Joint Requirements Oversight Council to recommend canceling the program in October 1995.⁽⁶⁾ The General Accounting Office also issued reports critical of Hunter and ultimately recommended its cancellation.⁽⁷⁾ The contract for low-rate initial production expired on January 31, 1996, and the acquisition program was terminated. Seven systems, each with eight air vehicles, were produced before cancellation and initially placed in storage.

Since then, however, Hunter has managed an impressive resurrection. The equipment of almost two complete systems has been removed from storage and is being used by the Army and Navy in training programs and in developing "concepts of operation" for how and when UAVs should be used by soldiers in the field. As part of those efforts, Hunters were employed in the Army's Advanced Warfighting Experiment. All seven Hunter systems have received a host of reliability upgrades, including improvements to the engine, data link, and flight control. In 1996 and 1997, Hunter flew over 3,000 hours of operations with only two serious mishaps. Indeed, an official with the Unmanned Aerial Vehicles Joint Program Office described Hunter as "the most reliable UAV program we have."⁽⁸⁾

The services, especially the Army, have also used Hunter to demonstrate various missions that UAVs are capable of performing, such as carrying communications and electronics intelligence payloads and laser target designators. In addition, the Navy has used parts of a Hunter system to practice integrating a UAV system more closely with Navy units.

Predator

Aside from Pioneer, Predator is the only UAV to have moved from development to full acquisition to operational deployment. It grew out of the Gnat-750 and Amber programs developed in the 1980s for the Defense Advanced Research Projects Agency and the Central Intelligence Agency.⁽⁹⁾ In January 1994, DoD gave General Atomics a contract to develop Predator under the Advanced Concept Technology Demonstration (ACTD) process, which is intended to give the eventual users of a system more role in its development and testing. Predator's first flight took place six months later, and the ACTD process was completed 18 months later with a decision to proceed to low-rate acquisition of the system in July 1996. That is not to say that the development process was entirely smooth or without problems. (For more on the ACTD process and how it affected Predator's development, see Chapter II .)

Predator is a medium-altitude, medium-range UAV that can provide near-real-time reconnaissance, surveillance, target acquisition, and battle-damage assessment day or night and in some difficult weather conditions.⁽¹⁰⁾ Predator's normal operating altitude is 15,000 feet, although it can function as high as 25,000 feet. Its maximum speed, 130 kilometers per hour, is actually slower than that of other existing and planned tactical UAV systems; its normal operating (or "cruise") speed is about 120 kilometers per hour. Aside from the sensor payload that the air vehicle carries, Predator's real assets are its endurance--more than 20 hours at its radius of 926 kilometers--and its communications system, which includes a satellite link. That means the air vehicle can operate beyond the line of sight of the ground control station and still relay images back to the user. Currently, the Air Force expects to acquire 12 Predator systems, each with four air vehicles and one ground control station.

The principal mission of Predator is to support the reconnaissance needs of the theater commander in a regional conflict. As such, it is not a system likely to be controlled by lower-echelon officers such as brigade commanders. After the cancellation of Hunter, however, the Army expressed hope that its division and corps commanders could use Predator to provide imagery in support of their missions. But unless the Army buys its own Predator systems, its division and corps commanders seem unlikely to get much support from the UAV, partly because so few systems are being bought and because a regional conflict would probably involve many higher-priority missions.

Predator has demonstrated its military usefulness in peacekeeping missions such as the recent ones in Bosnia. During the ACTD stage, several Predators were sent to Bosnia, where they helped NATO military commanders enforce the terms of the cease-fire. That included detecting troop movements in unauthorized areas, discovering previously unknown weapons factories or depots, and locating units that were breaking the peace.

Darkstar and Global Hawk

Darkstar and Global Hawk are high-altitude unmanned aerial vehicles that will provide reconnaissance, surveillance, and target-acquisition information to theater and higher-echelon commanders. Both UAVs are being developed as a single ACTD by the Defense Advanced Research Projects Agency, in part because the missions they are expected to perform complement each other. Global Hawk (also known as Tier II Plus) is supposed to be a "highly capable, moderately survivable" UAV, whereas Darkstar (also known as Tier III Minus) is expected to be a "moderately capable, highly survivable" UAV. The developers expect Global Hawk to have a maximum operating altitude of 65,000 feet and a radius of 5,556 kilometers, with about 24 hours of endurance at that distance (see Table 3). Darkstar is expected to have a maximum operating altitude of 45,000 feet and a radius of 926 kilometers, with around eight hours of endurance at that radius.
 

Global Hawk is a large aircraft--almost as big as a U-2 manned reconnaissance plane (see Table 4). It was not designed to be stealthy and therefore is likely to be vulnerable to high-altitude surface-to-air missiles. In contrast, Darkstar is being developed as a low-observable (stealthy) UAV that can penetrate enemy air defenses, perform its mission, and return. According to DoD, combining the capabilities of Global Hawk and Darkstar into one aircraft would be both technically difficult and extraordinarily expensive--hence the decision to pursue two separate air vehicles.
 

Both Global Hawk and Darkstar are being developed with a philosophy that uses cost as an independent variable. The only firm requirement is that the average cost of the 11th through 20th air vehicles--for both types of UAV--be no more than $10 million (in 1994 dollars). All other technical characteristics can be traded to fulfill that requirement.

The technical objectives for the two high-altitude UAVs stem from some broadly worded statements of mission needs for reconnaissance, surveillance, and target acquisition. Essentially, the requirement is for systems that can provide near-real-time reconnaissance, surveillance, and target acquisition to theater, midlevel, and tactical commanders and that can operate in a variety of environments--defended and undefended, contaminated and uncontaminated--without risking the lives of soldiers. For example, in justifying the development and procurement of both manned and unmanned long-range reconnaissance systems, the Joint Requirements Oversight Council determined that:

Warfighting commanders-in-chief (CINCs) have a need to provide commanders [with] a responsive capability to conduct wide-area near-real-time reconnaissance, surveillance, and target acquisition (RSTA), command and control, signals intelligence (SIGINT), electronic warfare (EW), and special operations missions during peacetime and all levels of war against defended/denied areas over extended periods of time. The evolution of the hostile surface-to-air and air-to-air threat and their collective effectiveness against manned aircraft and satellites can generate unacceptably high attrition rates. Current systems cannot perform these missions in a timely, responsive manner in an integrated hostile air defense environment without high risk to personnel and costly systems. There is a need for a capability which can be employed in areas where enemy air defenses have not been adequately suppressed, in heavily defended areas, in open ocean environments, and in contaminated environments. Nuclear survivability is required as necessary to perform missions in a nuclear contaminated environment, including operating in the presence of high-altitude EMP [electromagnetic pulses].⁽¹¹⁾

The Global Hawk and Darkstar ACTD has had various problems. Both air vehicles have experienced substantial slips in their schedules. The first Darkstar aircraft crashed on its second flight. And there are reasons to believe that both aircraft will have difficulty meeting their cost goals, although that will not be known for sure until the end of the ACTD process.

Outrider

Outrider is a tactical UAV that is being developed for the joint use of the Army, Navy, and Marine Corps. It is intended primarily to meet the reconnaissance and surveillance needs of brigade and task-force commanders. Like Darkstar and Global Hawk, Outrider is currently under development as an ACTD, and its only firm requirement is that its cost be no more than $350,000 by the 33rd air vehicle and no more than $300,000 by the 100th. Other technical objectives, which were laid down by the Joint Requirements Oversight Council, may be traded off against one another to achieve that cost requirement.

The technical objectives for Outrider stem from DoD's operational requirements documents for the previously planned Close Range and Short Range UAV systems. That earlier approach to tactical UAVs envisioned having two systems: one (with a radius of about 50 kilometers and endurance of three to four hours) that would provide imagery to brigade-level commanders, and another, longer-range UAV that would fulfill the requirements of corps and division commanders. As noted above, Hunter was intended to be the second system, the Short Range UAV. After Hunter was canceled in January 1996, the program to develop a tactical UAV--which was still the first priority of the Joint Requirements Oversight Council--was converted to an ACTD, and the technical objectives were set so that the new system would fulfill missions of both the Army and the Navy and Marine Corps. The system selected was Alliant Techsystem's Outrider, which had originally been proposed as the Close Range UAV.

Developing Outrider to meet the joint requirements has proved challenging. The program has experienced numerous schedule slips, and the air vehicle has had trouble meeting some of its performance goals during tests. The troubles were severe enough that in September 1997 the General Accounting Office issued a report recommending a delay in production of Outrider until all of the problems have been solved and the system's military utility has been demonstrated.⁽¹²⁾ However, officials of the Joint Program Office, which is in charge of managing the Outrider program, are cautiously optimistic that Outrider's problems will be overcome and that the ACTD will yield a useful system. Outrider has had more than 160 test flights, and program officials appear to be mitigating some of the technical problems, such as the excess weight of the air vehicle. Thus far, however, Outrider has had only a handful of test flights longer than three hours.
 

PROBLEMS WITH DoD'S UAV PROGRAMS

Although unmanned aerial vehicles appear to show great promise and many people have high expectations for them, the Congress is concerned that so many of the UAV systems that DoD has developed or is developing have experienced problems. Historically, many of the services' UAV programs have run into technical difficulties and cost growth. (For example, the Army's Aquila UAV was begun in 1979 and finally canceled in 1987 after its projected costs had more than doubled and it had met mission requirements on only seven of 105 test flights.)⁽¹³⁾ As Table 1 indicated, the result has been numerous development efforts but few deployed systems. CBO has identified three main areas of concern in the Department of Defense's current unmanned aerial vehicle programs: the suitability of the tactical UAV (Outrider) for its intended missions, overlaps in capability, and issues related to the operational control of UAVs on the battlefield.

Suitability of Outrider for Its Missions

The cancellation of Hunter in January 1996 left the Pentagon without a new generation of unmanned aerial vehicles that could fly out to 200 kilometers and collect imagery. As noted above, the Joint Requirements Oversight Council decided to revise and enhance the specifications for the joint tactical UAV--which ultimately became the Outrider program--so that system could fulfill the various requirements of the Army and of the Navy and Marine Corps. But three major differences exist between those services' requirements.

First, the Army wants an inexpensive air vehicle that has a range of 50 to 60 kilometers and can support a brigade commander by collecting intelligence in his immediate vicinity. In contrast, the Navy and Marine Corps need a UAV system with a much longer range--200 kilometers--to support littoral operations.

Second, the Navy and Marine Corps want a vertical take-off and landing capability in their UAV system. The Navy would like its UAVs to operate from any ship capable of carrying a helicopter, but at the very least it wants the UAVs to be able to take off and land in 75 meters, or about one-third the length of a large amphibious ship. A UAV that can take off and land vertically would certainly provide that capability, but it would probably be much more expensive than the system the Army wants. Outrider will not have that capability.

Third, the Navy strongly prefers that a heavy-fuel engine--one that runs on diesel or jet fuel--power its new UAVs. The Army would also like that capability, but not as much as the Navy. Diesel fuel is far less volatile and combustible than gasoline, which is highly flammable. The Navy wants to remove gasoline from its ships altogether to reduce the risk of fire and explosion. Gasoline requires special preparations and handling, whereas diesel or jet fuel poses less risk. Nevertheless, Outrider, as currently planned, will run on gasoline.

Overlaps in Capability

A second major concern is an apparent overlap in the capability of what DoD calls the endurance UAV programs: Predator, Global Hawk, and Darkstar. According to the Department of Defense, each of those systems fills a niche in the pursuit of intelligence. But they also appear to create redundant capability that may not be necessary since the United States today faces a less threatening military environment than it did during the Cold War.

The medium-altitude Predator, which is already in production, can operate at 25,000 feet; as currently planned, Global Hawk will be able to operate at up to 65,000 feet, and Darkstar at up to 45,000 feet. Both Predator and Global Hawk can stay aloft for nearly 24 hours at their operating radius, but Darkstar is more limited at eight hours. Global Hawk can also carry a larger payload than Darkstar, which means a more capable sensor package. However, Darkstar's great advantage is that it is expected to be stealthy, so it can operate in areas with strong air defenses. The redundant capability derives from the fact that both Predator and Global Hawk may be survivable in threatening environments, though probably not as survivable as Darkstar.

Operational Control of UAVs on the Battlefield

Together, the Pentagon's UAV programs represent a relatively small amount of money: $620 million in 1999. Nevertheless, they sometimes find themselves at the center of debates about strategy and policy. Such is the case with Predator and the way in which DoD will fight the "deep battle"--that is, attacking enemy forces some 150 kilometers beyond the forward line of U.S. troops.

The Air Force believes it should be primarily responsible for engaging enemy forces in the area beyond the fire-support coordination line (the line separating ground forces' and air forces' responsibility for conducting a battle), which is usually about 30 kilometers beyond the forward line of troops. The Army, however, is pursuing the concept of "maneuver warfare" and increasingly views the deep battle as its responsibility. It would probably like to extend the fire-support coordination line to 150 kilometers. That debate over strategy has not been resolved and has indirectly entered into questions of how Predator will be controlled and assigned its missions.

Without Hunter, the Army no longer has a UAV that can support its efforts to engage enemy forces far beyond the forward line of troops. Consequently, it is looking to Predator to fill that gap. But the Predators now being acquired are owned and operated by the Air Force. The Army envisions equipping its corps and divisions with ground control stations and data terminals and having the Air Force lend them Predator air vehicles, which they would control directly. After the air vehicles had performed the tasks that the corps or division commanders required, or when they needed resupply, they would be handed back to their Air Force controllers.

The Air Force, however, argues that it must maintain operational control of the UAVs at all times to preserve the integrity of the airspace over the battlefield. Predators must be integrated into the "air tasking order" (the Air Force's guidelines for who does what) so that friendly forces do not end up shooting them down. The Air Force has stated that it will support Army requests to use Predator once higher priorities (as set by the theater commander) have been met. But the Army appears to doubt that the Air Force will be sufficiently responsive to its requests during battle.

To address some of the above problems, CBO has analyzed five possible alternatives for DoD's UAV programs. Those options, which could make unmanned aerial vehicles more effective, are presented in Chapter III. Before that, however, this paper examines the effects of the ACTD process on the development and cost of UAVs.

1. Such combat-related missions may one day include using UAVs to conduct strike missions, suppress enemy air defenses, or carry nonlethal weapons, such as a high-powered microwave that could disrupt an enemy's electronic equipment.

2. Ltc. William L. Burnham, "TF Hunter Support to AWE" (briefing by the Army, National Training Center, March 1997).

3. Michael R. Gordon and General Bernard E. Trainor, The Generals' War: The Inside Story of the Conflict in the Gulf (Boston: Little Brown, 1995), pp. 387-389.

4. See, for example, David A. Fulghum, "UAV Succeeds in Electronic Combat," Aviation Week & Space Technology, January 26, 1998, p. 29.

5. The Army also used Pioneer but gave it up in 1995 in anticipation of the initial operational capability of Hunter.

6. The Joint Requirements Oversight Council is a body that reviews defense acquisition programs. It is composed of the vice chiefs of staff of the services and chaired by the Vice Chairman of the Joint Chiefs of Staff.

7. General Accounting Office, Unmanned Aerial Vehicles: No More Hunter Systems Should Be Bought Until Problems Are Fixed, NSIAD-95-52 (March 1, 1995); and General Accounting Office, Unmanned Aerial Vehicles: Hunter System Is Not Appropriate for Navy Fleet Use, NSIAD-96-2 (December 1, 1995).

8. "Official says 'Hunter most reliable UAV'; additional buy sought," Aerospace Daily, November 18, 1997, p. 267A.

9. Curtis Peebles, Dark Eagles: A History of Top Secret U.S. Aircraft Programs (Novato, Calif.: Presidio, 1995), pp. 209-214. See also Michael R. Thirtle, Robert U. Johnson, and John L. Birkler, The Predator ACTD: A Case Study for Transition Planning and the Formal Acquisition Process (Santa Monica, Calif.: RAND, 1997), p. 8.

10. The limitations that Predator does have in bad weather do not result from its sensor--which includes a synthetic aperture radar that can provide imagery through clouds and rain--but from the air vehicle itself. High winds and severe storms can sometimes impair or prevent the air vehicle from operating or from successfully executing its mission.

11. Department of Defense, Joint Requirements Oversight Council, Mission Need Statement for a Long Endurance, Reconnaissance, Surveillance, and Target Acquisition Capability, JROCM-003-90 (January 5, 1990).

12. General Accounting Office, Unmanned Aerial Vehicles: Outrider Demonstrations Will Be Inadequate to Justify Further Production, NSIAD-97-153 (September 1997).

13. Statement of Louis J. Rodrigues, Director, Defense Acquisition Issues, National Security and International Affairs Division, General Accounting Office, before the Subcommittees on Military Research and Development and Military Procurement, House Committee on National Security, published as General Accounting Office, Unmanned Aerial Vehicles: DoD's Acquisition Efforts, GAO/T-NSIAD-97-138 (April 9, 1997), pp. 1-2.

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