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For more than 35 years B-52 Stratofortresses have been the primary manned strategic bomber force for the United States. The B-52 is capable of dropping or launching a significant array of weapons in the U.S. inventory. This includes gravity bombs, cluster bombs and precision guided missiles.
An appreciation for the uniqueness of the B-52 requires a survey of over 35 years of modifications, missions, and changes in national security strategy. One must examine not only roles and missions but changing profiles, tactics, and weapons improvements in order to focus on the adaptive process. Certain key characteristics have made that process possible -- without these characteristics, the B-52 would not have met the challenges of almost three decades of service.
In 1945, the Army Air Corps initiated a design competition for a new second generation strategic bomber to follow the B-36. Following further requirements definition by the Army Air Corps in 1946, Boeing was awarded a design contract for this new aircraft. The original requirements specified an aircraft that could carry a 10,000-pound bomb load, 5,000 miles, at a tactical operating altitude of 35,000 feet. This aircraft was to be capable of cruising at a minimum of 450 miles per hour (mph) at its tactical altitude.
In trying to fulfill this ambitious requirement, Boeing faced serious problems in selecting an engine that could provide both the required speed and range. The emergence of the swept- wing, pure jet B-47, coupled with the Air Force's disenchantment over very large propeller engines, caused Boeing to initiate an in-house study with its own money. This study was for an all jet bomber, able to fly the desired mission, using a new engine being designed by Pratt and Whitney. The results of this study, and further testing of the B-47, led Boeing towards the final eight engine jet design of the B-52. As the design matured, additional technology was taken from the B-36 and the B-47. Thus technology, in turn, became a primary determinant of operational requirements. Military aircraft designs matched available technology and then incorporated refinements that appeared technically or scientifically sound to achieve best performances.
By early 1949, Boeing was preparing two prototypes, the XB-52 and YB-52, both of which had been contracted for in early 1947. Although the YB was designated for service test, both models were used to refine the original design. These aircraft, weighing 390,000 pounds apiece, would be two of the largest aircraft ever built.
Even as these airships were being built, SAC requested Boeing to examine the possibility of developing a reconnaissance version. This was the first hint of interest in expanding the original nuclear strike mission specified for the B-52. The result of the SAC request was a design which could be assigned either a bombing or reconnaissance mission with no sacrifice in efficiency or performance. Although this capability was not integrated into the aircraft until introduction of the B-52B, it marked the initial swing towards mission flexibility in the B-52.
The major design emphasis was placed on superior performance with minimum airplane and system complexity. This was to be achieved by a straightforward design which provided a high standard of systems utility and functional reliability. To do this, however, required a number of innovations not anticipated in the original specifications. Some of the design features, like the on-board hydraulic system, were physically the largest yet built, while others like the pneumatic system which powered many aircraft accessories were radical departures from conventional designs. Nonetheless, the original flight test in 1952 proved successful, with performance exceeding the original specifications.
Despite initial optimism, it was apparent that additional development would be required. Of the original batch of 13 aircraft, which would normally have carried a test prefix but were so costly and vital that they were regarded as likely to go straight into the active inventory, the first three were completed as B-52A's and the rest as B-52B's. The A's, which never entered the active inventory, were used for additional development work.
Delivery of the B-52B in 1955 marked the first of over 740 aircraft, a serial production that included seven different models with each offering technological and operational improvements.
The use of serial production greatly improved the ultimate utility of the B-52 weapon system.
(1) Increases in internal fuel capacity created by design changes from a bladder to an integral wing and advances in engine technology with the introduction of the fanjet resulted in a 1,400-nm increase in combat radius.
(2) Technology advances in basic avionics designs, specifically within the bomb-nay and heading systems, improved both navigation and weapons delivery accuracy. The original components of these serial improvements formed the basis of subsequent updates to incorporate new weapons, delivery tactics, and methods of navigation.
(3) Refined and larger capacity subsystems between each series improved general subsystem performance and reliability. The larger subsystem capacities of later models proved to be a major key in B-52 flexibility and adaptability to changing mission requirements. For example, in the early series designs, small capacity electric alternators and dependency on pneumatically supported subsystems limited avionics growth to small marginal demand systems. Although adequate to support the initial configuration, these production subsystems offered limited flexibility with only small growth capacity. The larger capacity subsystems of later mission design and series (MDS) B-52's, redesigned to reduce pneumatic dependency, proved to be much more flexible and adaptable to the demands of improved bombing, navigation, electronic defense equipment, and other future modifications.
(4) Serial production also provided more timely improvements in aircraft defense by incorporating new technology in later MDS production without the expense or delays of modifying an entire fleet of aircraft. Redesigned and later totally new fire control systems, coupled with upgraded ECM suites, increased the survivability of each new series.
Although not new, this idea of serial production had a profound impact on the usefulness of the B-52. To appreciate this fact, however, it is necessary to understand how the weapon system has been able to adapt over time to changing requirements. To quote Mr. Walter Boyne, Assistant Director of the National Air and Space Museum: ''Had the original . . . design not been so superior, the Air Force would have opted long ago for a new airframe."
When the first production B-52 was being delivered in the mid-1950's, US national security strategy was based upon nuclear superiority and an ability to respond to any aggression with massive retaliation. The primary force objectives outlined at the time were (1) to deter war, (2) resolve conflicts on terms favorable to the United States, and (3) maintain a high state of readiness at a reasonable cost. In short, US strategic forces were prepared to fight a nuclear war with tactics similar to World War II. US nuclear forces, through strategic airpower, provided a nuclear umbrella for America and its allies.
B-52 capabilities became the benchmark for future bomber aircraft. Concurrently, there was a growing awareness of Soviet air defense improvements and its potential impact on US bomber forces. General Curtis LeMay, then Commander of SAC, expressed concern that large aircraft like the B-52 would soon require additional ECM equipment for self protection. As a result, in May 1958, Sperry, the prime ECM contractor, brought in eight additional companies to help design a major update of the whole ECM systems Improved defensive systems were incorporated as engineering change proposals in the midst of production.
During the same period, SAC issued a new requirement for a low level bombing and navigation capability to improve bomber penetration and survival. By 1958, operational reports from covert U-2 operations indicated "that the Russians were tracking some of the U-2 flights and that surface-to-air missiles (SAMs) were being fired . . . some of which were coming uncomfortably close to the U-2s operating altitude." This confrontation helped prompt revision of tactics for the B-52 and was the first of several new, major changes.
Although the new low level requirement would apply to the other SAC bombers, it would have its greatest impact upon the B-52. To fly the new attack profile, the B-52C through H models were modified with a new terrain avoidance radar, an improved radar altimeter, increased cooling capacity for sustained low altitude operations, modified equipment mounts, and a general strengthening of the aircraft's secondary structures. The goal was to permit reliable, all-weather operation at 500 feet, to avoid detection, and to minimize encounters with enemy defenses. Low level training for SAC bomber crews began in the late 1950's, with actual aircraft modification beginning in 1961.
While the low level penetration tactic was being refined, new weapons developments in the form of the ADM-20 Quail and the AGM-28 Hound Dog were also being pursued. The Quail, an improved defensive capability initiated in the late 1950's, was a decoy missile designed to be carried in the aft bomb bay of a B-52 for launch while en route to the target. The missile was programmed by the crew to fly at approximately the same speed and altitude as the B-52. Its primary mission was to confuse enemy radar by creating a reflected image similar to the carrier aircraft.
The Quail system was retrofitted in 1960 on the B-52E through G and was subsequently added to the B-52H. This missile was the first of a number of unique capabilities added to various models of the B-52. It was unique because the B-52 could carry four of these 13-foot-long 1,200-pound missiles in its 27-foot-long bomb bay in addition to the regular nuclear payload. The decoy system proved to be a workable option for penetration enhancement of the large radar cross section bomber because it served to dilute and ultimately saturate the Soviet defense system. Defense improvements and system maintenance problems forced retirement of the ADM-20 in the mid- 1970's.
In a program similar to Quail, North American Aviation developed a miniature vehicle powered by a turbojet engine. Named the Hound Dog, the AGM-28 missile could fly at altitudes from 500 to 60,000 feet at speeds above Mach 2. Programmed by the crew during captive carry, it was used to penetrate high threat terminal defenses, allowing the bomber to avoid overflight. The missile could perform feint attacks or preset maneuvers while flying its nuclear warhead out to a 600-mile range. The B-52C and all subsequent models were modified to carry two AGM-28 missiles, one under each wing on large hard points. The modification to carry AGM-28's had two major impacts on B-52 operations. First, like the low level capability being developed, the addition of Hound Dog altered the B-52's nuclear strike profile. The second major impact was the degradation of the B-52's range. Two Hound Dog missiles and the associated launch gear, totaling over 40,000 pounds, were forcing the B-52 to carry less than full fuel loads in order to remain within design weight limits. When carrying the AGM-28, the normal procedure was to run the missile's engines in flight to augment the bomber's thrust. To accomplish this and still get maximum range after launch, the missile was refueled by the bomber during captive carriage. In addition, these 45-foot-long missiles created a drag penalty that increased fuel consumption. This reduced the bomber's range on the order of 8 to 17 percent and increased tanker dependency.
The use of extended low altitude operations to insure the B-52's penetration capability further degraded the design strike range. The overall inefficiency of jet engine operations at low level, coupled with slower operating speeds, greatly reduced range at low altitude. For example, if the B-52H flew at high altitude on a nuclear strike mission, it had a maximum unrefueled range of approximately 9,000 nm. On a similar strike mission with 2,400 nm flown at 500 feet, the operations planners could count on only a 6,300-nm range with the addition of one refueling.
Despite the reduction in range resulting from the added weight, drag of new weapons, and the penalties of low altitude flight, strategic planners were beginning to appreciate the inherent flexibility of the large bomber. The changing penetration profiles and development of air-to-surface missiles, which allowed the bomber to avoid the heavily defended areas, was a recognition of improving Soviet defensive capabilities and marked a change in US tactics for strategic warfare. Flexibility became the watchword and adaptability the key to continued bomber operations.
In addition to tactical weapons developments for the B-52, the United States and Great Britain were pursuing a common initiative that would arm the heavy bombers of both nations with a new air-to-surface ballistic missile, Skybolt. Although a few B-52's were actually modified to carry this system, Skybolt never became operational. Bill Gunston, in his book Bombers of the West, describes this missile program as "marked by all the headwinds and diversions of an enterprise that is dominated by politics rather than mere technical problems." Secretary of Defense McNamara, in discussing ways of extending the life of the B-52 in an era of increasingly sophisticated enemy air defenses, dismissed the Skybolt program as having the disadvantages of both the bomber and the ICBM.
Although the Kennedy administration cancelled the Skybolt program, it accelerated the forces of change by announcing a new national security strategy called Flexible Response. This strategy was initially based upon withholding an "Assured Destruction" capability with a goal of damage limitation in a nuclear exchange. The strategy shift from massive nuclear retaliation to flexible response resulted in new emphasis being placed upon the full spectrum of operations, thus necessitating larger conventional force capabilities. Under this new approach, conventional forces were to be sufficiently large to prevent escalation of any hostility to the nuclear threshold.
Secretary of Defense McNamara did not favor the strategic bomber as a major deterrent system; yet, he did recognize its utility and potential flexibility. In testimony to Congress, he described the strategic retaliatory forces as needing sufficient flexibility to permit a choice of strategies suitable to
(1) strike back decisively across the entire spectrum of the Soviet target system simultaneously;
(2) strike Soviet military installations associated with their long-range nuclear forces in an effort to reduce the power of any follow-on attack; and
(3) if necessary, strike back at Soviet urban and industrial complexes in a controlled and deliberate manner.
He continued by saying the bomber's utility lay not in numbers or promptness but in its ability to be employed selectively against hard counterforce targets that are not time sensitive.
In 1961, as a demonstration of new flexible response options and in recognition of a demonstrated Soviet ICBM threat, the United States commenced a strategic option unique to the heavy bomberairborne alert. The physical size, endurance, payload, and range of the B-52 made the 27- to 30-hour missions feasible. Through in-flight refueling, an adequate number of bombers could be kept continuously airborne to meet national objectives. This alert posture often included medium range bombers, but their limited range and endurance further taxed the available aerial refueling capability. As General Powers, then the Commander of SAC, explained to Congress: "This demonstration of resolve with airborne alert must impress Mr. Khruschev [so] that he cannot strike this country with impunity."
The general acquisition strategy of the early 1960's supported a buildup of the ICBM and SLBM legs of the TRIAD with only limited modification to the bomber force. As a result of the great operating cost differential between the newer missile systems and the older aircraft, the prompt "Assured Destruction" capability of the ICBM was less expensive than its bomber counterpart. Believing that the true value of the strategic bomber lies in a limited counterforce potential, the Secretary of Defense suggested that the existing B-52's, originally designed for a 10-year life, could satisfactorily provide this capability. The only unknown was how long a limited force of bombers could penetrate the expanding Soviet air defense umbrella.29 As a hedge against this uncertainty, Secretary McNamara authorized studies for a possible B-52 replacement. No major capability updates were initiated for the B-52, and only those improvements needed to continue the force were supported.
With the change in strategy and the lessening of interest in the strategic bomber, production of the B-52 ended in the summer of 1962 after a run of nearly 7 1/2 years. The last of the B-52's, an H model, was delivered to the 4135th Strategic Wing at Minot AFB, North Dakota, in October 1962. Although physically resembling the other B-52's, this last MDS marked the first time in the history of strategic bombing that an aircraft had been designed explicitly for a low altitude penetration mission. It required about 120 structural modifications to withstand the aerodynamic forces encountered at low level. Once production terminated, however, subsequent improvements became a function of the versatility and adaptability of the original design.
Even as the B-52 was losing support for its traditional strategic nuclear strike role, a brush-fire insurgency in South Vietnam was beginning to test the flexible response capability of the conventional forces. By 1965, SAC's B-52's were being called upon for bombing support for friendly forces in South Vietnam. Initially, raids were conducted by B-52F's carrying 51 750-pound general purpose bombs, but rapid plans were made to increase the conventional capability of the B-52D force for a sustained SAC operational presence. This program, dubbed Big Belly, upped the internal weapons load of the D model from 27 to 84 of the 500-pound bombs and added a 24-weapon carriage externally. With the completion of Big Belly, the B-52D would carry nearly 60,000 pounds of ordnance. Although other models of the B-52 were also used in Southeast Asia, only the B-52D was modified for the high density conventional capacity, a capability that no existing aircraft can rival. This rapid change in missions for the B-52 was made possible only because of the volumetric capacity, enormous lifting abilities of the aircraft, and structural integrity of the basic design. The net result was a geometric increase in conventional firepower.
The surge requirement for World War II type area bombing generated other changes within the B-52 force. As a large portion of the active B-52 fleet was integrated into the war effort, the aircraft underwent modifications to improve ECM effectiveness against the SAM and interceptor threat possessed by the North Vietnamese. The firepower versatility of the B-52 was expanded by certifying the aircraft for a greater number of conventional weapons such as mines and cluster bomb units. Such weapon payloads boosted the psychological value of the strategic bomber as a terror weapon to the adversaries.
The initial experience in Southesast Asia of long-range B-52 operations in a hostile air defense environment caused a change in thinking regarding the utility of strategic aircraft. The war diverted funds needed for strategic modernization, while at home independent studies into the need for a new penetrating bomber generated a wide difference of opinion. The Air Force sought an immediate replacement for the B-52, requiring an aircraft that had broad spectrum applications that was capable of supporting both the traditional nuclear role and the newly emphasized conventional role. The Secretary of Defense, however, sought less costly options with the hope that weapons improvements and/or tactics changes would provide the desired survivability for the penetrating bomber force. With the B-52 beginning to prove its value in actual combat over Vietnam, its worth as a nuclear penetrator was being viewed with increasing skepticism. During the mid 1960's the Soviet air defense system blossomed to approximately 9,000 SAM missiles and 3,500 interceptor aircraft. These large numbers and the practical experience of Southeast Asia demonstrated the density and sophistication of the defense environment. This served to reinforce both Air Force and DOD studies which predicted high attrition rates for the existing attack profiles of current bombers in the high threat environment.
As early as February 1965, the Secretary of Defense indicated an interest in a new ballistic short-range attack missile as a means of reducing aircraft exposure. This weapon, being studied in conjunction with the manned strategic aircraft, would preclude the need of penetrating heavily defended target areas. In 1966, as in earlier testimony to Congress, Secretary McNamara again played down the role of the manned bomber in the current force structure and the need to expend monies for a B-52 replacement. He further recommended that a force of approximately 255 B-52G's and H's would be adequate insurance against failure of the ICBM leg of the TRIAD. As an additional initiative, Secretary McNamara recommended that a bomber version of the F-111 be built as a countervalue system to complement the older and more vulnerable B-52 and that the new short-range attack missile (now called SRAM) be accelerated to coincide with the new bomber. The Secretary also directed that preliminary avionics integration design studies be initiated to permit a SRAM retrofit for the B-52 should it be required.
In his last annual testimony before the Senate Armed Services Committee in January 1968, Secretary McNamara described the major pacing item for maintaining the utility of the strategic bomber as the development of improved penetration aids to counter the postulated Soviet interceptor threat. McNamara continued by recommending that the B-52G and H models remain operational for the foreseeable future. He added that it was important to develop common advancements usable by both older aircraft and candidate replacements as penetration aids in the 1970's.37 He outlined this program as including continued:
The first step of the Secretary's programs, the addition of SRAM to the B-52, would provide a large increase in nuclear firepower. The G and H models were ultimately modified to carry up to 20 of these supersonic short-range nuclear missiles without downloading existing gravity weapons. Eight SRAMs were carried internally on a special rotary launcher in the aft bomb bay, and 12 SRAMs were mounted on wing pylons with 6 missiles under each wing. The total weight of the missiles and their launch gear was approximately 68,000 pounds. In addition to the missiles, a number of aircraft systems modifications were made to add interface equipment for programming and launching the SRAM.
As part of the second step of the Secretary's program, the Phase VI ECM modification was proposed for the B-52G and H. Called Phase VI, because it was the sixth major ECM program for the B-52, it improved the aircraft's self-protection capability in the dense SAM environment. The equipment added during this modification would expand signal coverage, improve threat warning, provide new countermeasures techniques, and increase the quantity of expendables. The power requirements of this modification would also consume most of the excess electrical capacity on the B-52G.
In addition to improved countermeasures, the Air Force recommended that the B-52G and H also be modified with the electro-optical viewing system (EVS) to enhance low altitude penetration. EVS is a system containing a low-light television and a forward-looking infrared camera to display information needed for penetration at lower altitude. It improves the pilot's probability of hazard avoidance and gives the crew a true damage/assessment strike capability. The addition of a low-light television and a forward-looking infrared system was the first major application of this technology for terrain avoidance uses. The sensors were outgrowths of equipment used for special operations in Southeast Asia, and when integrated with the existing B-52 avionics, improved the aircraft's overall mission effectiveness under all conditions.
SRAM, Phase VI ECM, and EVS, like Hound Dog, Quail, and the use of low level tactics, marked a major shift in the B-52's utility. The modifications of the late 1950's and early 1960's had been applicable to a large portion of the entire B-52 fleet and had greatly altered the tactics and weapons used for strategic nuclear attack. The modifications of the late 1960's and early 1970's were quantum leaps in technology applicable to only a small portion of the B-52 force. By 1970, approximately half the total inventory of B-52's built had been retired with only half of those remaining scheduled for SRAM, Phase VI, and EVS. These updates, although not substantially altering the missions established in the early 1960's, would greatly change the overall capabilities of the B-52 as a strategic bomber. They would also serve as baseline requirements thought necessary for future aircraft development.
These modifications, in addition to substantial capability improvements, had a second, very important impact on the B-52 since those changes would use a large percentage of the remaining excess subsystem support capacity; so much in fact, that these updates could not be considered for the older B-52D and F without costly upgrades to their electrical, hydraulic, and environmental control systems. Additional subsystem capacities designed into the later production B- 52's provided the edge which allowed this next round of capability improvements. At the completion of SRAM, Phase VI, and EVS, the operating weight of the G and H models had grown by nearly 24,000 pounds over the initial delivery weighty This new operating weight was extracting a penalty on operational range on the order of 8 to 11 percent. But this loss was acceptable when compared to the associated increase in capability.
The introduction of the first of these modifications in the early 1970's was accompanied by a refinement in national security strategy. Implemented under Secretary of Defense Schlesinger, this new strategy was oriented towards providing the NCA more flexibility through increased options in the use of the military instrument. As part of this option-oriented strategy. the bomber concept of operations required increased flexibility to provide a capability across the entire spectrum of conflict. The modifications were excellent complements to this new strategy, giving the B-52 greater flexibility, responsiveness, and survivability.
The need for flexibility within the new strategy returned the heavy bomber to a prominent place within the TRIAD. The heavy bomber emphasized both size and range so that sufficient penetration aids could be carried to cope successfully with the projected defenses; and once into enemy territory, a large enough payload would be available to effectively do the job. In addition to SRAM, a second new missile weapon was being discussed for the B-52. Christened SCUD, for subsonic-cruise unarmed decoy, this system would, like Quail, resemble the B-52 on radar. As an active decoy, it would carry ECM and other devices, and it had a range of several hundred miles. Eventually, plans called for the missile to carry a nuclear warhead as an armed decoy so that even after discrimination from the bomber, defense assets would have to be diverted to destroy it.
The introduction of SCAD as a candidate system in 1969 was to portend a third major profile change for the B-52, that of a cruise missile carrier. The SCAD concept was devised and validated based upon the projected threat of the 1980's. At the time, SCAD was not envisioned as a replacement for the penetrating bomber; but like earlier modifications, an adjunct to extend the life of the B-52. Although SCAD was never deployed operationally, the concept of a long-range cruise missile weapon ultimately was accepted, becoming known as the air launched cruise missile (ALCM-A).
With SRAM, the bomber could strike heavily defended targets without entering the terminal defenses; the cruise missile provided the alternative of striking from greater distances and thereby increasing the lethal footprint of the bomber. A larger laydown footprint for the strike system translated directly into greater versatility and flexibility of response, effectively giving back to the B-52 the range which the added weight of past modifications had taken away. With the greater footprint, a larger target base could be covered by a fixed number of delivery vehicles. It was believed that a large number of cruise missile-type weapons would serve to dilute and eventually saturate enemy defenses, thereby improving the survivability of the launch vehicle. These characteristics were becoming operationally important in a relatively dense, high threat environment with an expanding target base.
By the early 1970's, it was apparent that the Soviets would stop at nothing less than military parity with the United States. The Nixon administration, in continuing the national commitment to a TRIAD, authorized development of a prototype B-1 bomber as a replacement for the B-52.
Development of a new bomber throughout the early and mid- 1970's paralleled continued contemporary research into cruise missile technology. Technology had developed propulsion, guidance, and structural materials for a cruise missile that could greatly alter the profile of the bomber aircraft. In June 1977, President Carter announced his intent not to produce the B-1 but to again extend the life of the B-52 by modifying it to carry a longer range air launched cruise missile, the ALCM-B. With the associated avionics changes, this proved to be the largest single modification ever made to the B-52. It would have the greatest impact in terms of overall aircraft capability and potential missions. Unlike previous weapons developments, the ALCM-B captured the latest in technology to allow for a small, long-range, highly accurate weapon. Unlike the Hound Dog, 20 ALCMs would be carried on the B-52. And unlike the SRAM, the ALCM-B would allow the carrier aircraft, in many instances, to avoid overflying the enemy homeland. As envisioned by the planners, ALCM carriage would remove the B-52 from its penetrator role to the less demanding and less threatened role of a missile launch platform. The B-52 cruise missile carrier would, in many cases, launch its payload beyond the range of the majority of land-based threats. By avoiding both the terminal SAM threat and the en-route LD/SD fighter threat, the B-52 will remain a viable weapon carrier throughout this decade and into the next. It is interesting to note that in the 1980's the B-52 will perform the mission it was originally designed fora long-range, high-altitude bombing platform.
These proposed modifications in role change would drastically alter the original design capabilities of the B-52. Virtually, the entire bombing and navigation systems would be replaced by a state-of-the-art digital navigation system.
Of all the changes, however, the ones with the greatest impact were the ones that affected the physical characteristics of the aircraft. When fully integrated into the B-52, the 20 ALCM-B's and their launch equipment will weigh approximately 76,000 pounds. The aircraft will carry six of the 20-foot-long missiles under each wing on 40-foot-long pylons. The eight remaining missiles are carried internally like SRAM. But to carry these weapons, the B-52 must download an amount of fuel equal to their weight to remain within the maximum gross weight limit. In addition, a range penalty of approximately 10 percent results from the added drag of the pylon-mounted missiles. It is estimated that the total range penalty for displaced fuel and drag may approach 25 percent. In addition to decreasing aircraft range, the ALCM requires electrical, hydraulic, and cooling support from the B-52's subsystems. In some cases, this exceeds the existing capacity of the B-52, for these systems already represent over 20 years of modifications.
The advent of the ALCM and its integration further extended the useful life of the B-52. In 1982, as the first B-52G cruise missile carrier assumed alert, the weapon system is well into its third decade of operation. The original nuclear mission has been expanded and the strike profile has come full circle as the B-52 has adapted to- changing national strategies and priorities. Its unique characteristics have allowed it to achieve different objectives, in different circumstances, against different adversaries. Through this adaptive process, the capabilities of the B-52 have been broadened to provide firepower across the spectrum of conflict. Even though technology has advanced tenfold since the advent of the B-52, it still remains the mainstay of the bomber force.