The Lion’s Share of Power Projection

June 1, 1993
In future major regional conflicts, national political and military leaders are likely to place a premium on US forces that can deploy rapidly over long distances, swiftly destroy invading armored forces as well as fixed assets, and engage the enemy effectively while placing minimal numbers of American service personnel in harm’s way.

A quantitative analysis taking these factors into consideration shows that landbased air forces-heavy bombers and fighter-bombers-are likely to provide the lion’s share of US power projection capability in future conflicts, at least during the critical days or weeks of the war.

The analysis shows that US heavy bombers, with long range and large payloads of effective weapons, have the potential to project conventional firepower rapidly and effectively, providing critical capabilities early in a “short-warning” conflict. In the opening days of such a war, bombers are uniquely capable of delivering heavy firepower against fixed targets and, in the case of the stealthy B-2, invading armies.

The ability of bombers and fighters to realize the potential ascribed to them in this analysis depends critically on the development and procurement of large numbers of modern munitions and on enhancements to the bombers’ avionics. This capability is also dependent on the development of operational concepts that facilitate the survivability of bombers and on developing the planning tools necessary to employ standoff weapons.

Landbased tactical fighter-bombers can play the dominant role in US combat operations within a few days of the start of a deployment. These planes can deploy rapidly to distant theaters, requiring a modest amount of airlift relative to their combat power. In large numbers and equipped with modern munitions, landbased fighter-bombers can rapidly destroy large formations of enemy maneuver forces and fixed targets. The contribution of these forces to US military capabilities does not appear to be overly sensitive to access to forward bases in the theater of operations, given sufficient tanker support.

Changing Role for Naval Forces

Without question, carriers and other naval assets play a number of important roles in US military strategy. If properly located, carrier-based aircraft can play a useful role early in a short-warning war, helping to establish an air defense and conducting initial strikes on some surface targets.

In particular, the ability to project power ashore, suppress defenses, and establish an air defense over arriving forces in the first week of a campaign is very important. This capability can be enhanced by positioning naval forces in proximity to the theater of operations during the time of crisis preceding a major theater conflict.

However, a rationale for investment in these forces cannot be found in an examination of large-scale air-to-ground operations.

In theater warfare, US maritime power-projection forces–carrier aviation and Tomahawk land-attack cruise missiles–play a relatively minor role in destroying an enemy’s fixed assets and ground forces, which are two important operational objectives assigned to air forces. The relatively slow deployment speed of warships, limited number of strike aircraft deployed on carriers, and comparatively modest payloads of these aircraft all limit the contribution that even a large, modernized carrier force can make to large-scale air operations. A major improvement in carrier arrival rates (which would require massive investment) would not appreciably change this assessment.

In this analysis, we examined air forces in the context of major theater conflicts. Theater warfare has been and is now the primary determinant of general-purpose force structure. Future regional conflicts will likely possess several characteristics that will shape our approach to fighting them. Few US forces will be deployed in the region at the outbreak of hostilities; history shows that the US usually fails to anticipate the outbreak of conflicts. US friends and allies may be badly outnumbered by hostile forces. The adversary-Iran, Iraq, North Korea–will possess large ground forces, including sizable armored formations and perhaps nuclear weapons. US decision–makers and the public will wish to minimize the risk of heavy US casualties.

The contributions of US airpower assets to future theater campaigns should be assessed in a “zero-warning” scenario–that is, an adversary attacks an ally or friend before the US can deploy more forces into the region.

We assumed an attack of ten armored and mechanized divisions, supported by additional infantry divisions–a force that could be fielded by a number of regional powers. Our “baseline” case posited an attack by Iran or Iraq against Kuwait and Saudi Arabia; our second case postulated a North Korean attack on the Republic of Korea.

We assessed the capabilities of selected US airpower-projection assets-bombers, landbased and carrier-based fighter-bombers, and Tomahawks–in these scenarios set around the turn of the century. Several new types of air-delivered munitions will be available by then, and these were included in the analysis. No new aircraft types were considered, although existing types may undergo upgrades or life extensions. The study assumed that US and allied ground forces play a major role in halting the enemy invasion.

High-Priority Objectives

In future theater wars, US and allied leaders are likely to have several high-priority objectives. Three to which ground-attack aircraft would contribute directly are destroying enemy war-making capacity by destroying fixed assets; halting and destroying the invading force; and destroying dug-in ground forces. We compared the contribution of airpower assets to each of these objectives, by translating them into quantifiable measures of evaluations (MOEs).

MOE 1: Tons of precision ordnance deliverable against fixed targets. These targets would include such assets as high-level command posts and communications facilities, military storage areas, oil refining and distribution facilities, airfields, and bridges. We estimated that a regional opponent might present approximately 500 such targets, which might be associated with approximately 4,000 aimpoints for attack with conventional weapons. Recognizing that the enemy will be able to repair some of these assets following attacks on them, we set an initial threshold of adequacy for such attacks at 6,000 tons of precision ordnance delivered, or approximately 1.5 tons per aimpoint.

MOE 2: Tons of ordnance deliverable against moving vehicles. An attack of ten armored and mechanized divisions would include 2,000 to 3,000 tanks, 6,000 to 7,000 armored personnel carriers, and as many as 25,000 “thin-skinned” vehicles, such as trucks and mobile surface-to-air missile (SAM) units. Depending on the level of opposition, an attacking force of this size would likely be stopped when fifty to sixty percent of its vehicles (and their contents) had been destroyed or severely damaged. At this point, the combat power of the attacking force would be reduced to roughly four armored division equivalents-about the size of Kuwaiti, Saudi, and arriving US ground forces that might be opposing the attack. We estimated that it would require 3,500 tons of specialized munitions to inflict this level of attrition.

MOE 3: Kill potential against revetted armor. When an army stops and digs in, it presents a target different from an army on the move. Assuming that air forces inflict sixty percent attrition on the invading force before it stops, between 3,200 and 4,000 armored vehicles would remain. We set our benchmark at 3,500. Using a high-side benchmark is appropriate, given that the invading force might stop before sixty percent attrition, US ground-attack aircraft will be called on to do other tasks, and targeting uncertainties will prompt multiple “kills” on vehicles.

The rate at which US forces can deploy to the theater of war is an important determinant of their ability to contribute to the campaign. Obviously, this is particularly true in cases in which a conflict starts prior to or during large-scale US reinforcement. Our analysis incorporated the following basic assumptions about US force deployments:

• One carrier battle group (CVBG) is on station within range of the conflict at the outset. A second CVBG arrives seven days later, and a third on Day 14. Each CVBG is assumed to have forty embarked attack aircraft-twenty A-6Es and twenty F/A-18s.

• Brigade-sized Marine units with accompanying aircraft arrive on Days 7 and 14.

• Ninety percent of the Air Mobility Command’s (AMC) transport aircraft are available for use by Day 4. Assets from the Civil Reserve Air Fleet (CRAF I and II) are available by Day 4 as well. We assumed that only forty percent of total airlift capacity goes to support USAF’s deployment and combat operations.

• Munitions for USAF fighter and fighter-bomber units must be airlifted to the theater until Day 10, by which time munitions from prepositioned stocks will be available. Bomber munitions are predeployed at Guam, Diego Garcia, and RAF Fairford, UK.

Support Assets Needed

Of course, a host of support assets must be deployed if the shooters are to operate effectively. In estimating deployment rates for “bomb-droppers,” we took account of this need. We deployed to our baseline major theater conflict thirty squadrons of USAF fighters and fighter-bombers, sixteen B-2 bombers, and forty B-1Bs. We also employed forty B-52Hs from bases in the US.

Assumptions used for weapon loads for MOEs 1 and 2 are shown in the chart on p. 39. Also shown is the assumed sortie effectiveness for MOE 3 and sortie rates for all aircraft types. Weapon loads reflect typical combat loadings; sortie rates are based on those achieved during the Gulf War. Vehicle kills per sortie are far less than the theoretical maximum for each type of aircraft. Only aircraft capable of delivering homing weapons, such as Maverick missiles and laser-guided bombs (LGBs), are counted.

We compared aircraft and munitions that will be available around 2000. This implied the use of existing aircraft (with some upgrades) but several new, advanced munitions. Among them are inertially aided, GPS-guided (IGPS) unitary bombs, such conventional cruise missiles as the Triservice Standoff Attack Missile (TSSAM) and ALCM-C for the bombers, and such area antiarmor munitions as Skeet submunitions.

Finally, before comparing the various elements in terms of our three MOEs, it was necessary to specify some rules to allocate the force among the three MOEs over time. We assumed:

• At the initiation of hostilities, US and allied commanders would give top priority to stopping the invading force as soon as possible (MOE 2). To the extent possible, aircraft capable of effectively attacking moving vehicles would be pressed into that role until the invasion was halted.

• Aircraft not suitable for early attacks on moving armor (e.g., the F-117, which is not equipped with tactical munition dispensers; the B-1 and the B-52, which may be vulnerable to SAMs; and the TLAM) would be assigned to attack fixed targets (MOE 1).

• Once the attacking forces were halted, aircraft capable of delivering LGBs or Mavericks would attack surviving armored vehicles, which were assumed to have dug into revetments (MOE 3). The exception to this rule is the F-117, which would continue attacking fixed targets.

• Fifty percent of the F-15Es, F-16s, A-6Es, and F/A-18s (to a maximum of ninety-six) were assigned to suppression of enemy air defenses for the first five days of the war. Between Day 5 and Day 10, twenty-five percent performed SEAD. After that, the “SEAD tax” on these jets dropped to fifteen percent.

Having laid out these assumptions and constraints, we were ready to calculate the contributions of each type of aircraft to each of our three MOEs.

Bombers to the Fore

The assumption that a carrier battle group is on station and within range of targets at the start of the conflict is an important one. While the carrier’s ground-attack capabilities are limited, they provide a supplement to the B-2 in the earliest days of the war and, over time, a significant portion of the overall capability for this MOE, if one assumes that carrier attacks can be sustained for two to three weeks.

Figure 1 on p. 40 shows the relative contributions of aircraft to MOE 1 in a single major regional war scenario. It is, essentially, a “snapshot” of the cumulative effort against this MOE on Day 12 of the war-the point at which our threshold of 6,000 tons of precision ordnance was exceeded.

Figure 1 shows that the Air Force’s heavy bombers do the bulk of the work of attacking fixed targets. B-52s, B-1Bs, and the carrier battle group deliver cruise missiles for the first five days of the war, after which the B-1Bs are assumed to deliver IGPS bombs. The B-2 also delivers IGPS bombs, such as Joint Direct Attack Munitions (JDAMs). Tactical air assets contribute to MOE 1 after the threshold for MOE 2 is reached (Day 9) and deliver laser-guided and IGPS bombs. The F-15E provides most of the tactical air contribution. The effectiveness of standoff weapons is predicated on the functioning of timely intelligence and the development and fielding of a mission planning system.

Figure 2 provides an analogous picture for MOE 2–attacks on moving columns of vehicles. The B-2s are assumed to begin attacks on Day 1, launching from their bases in the US and recovering at Diego Garcia. They are responsible for the bulk of the ordnance delivered (e.g., guided CBU-97s) against the columns in the opening days of the war. By Day 9, however, when the threshold for MOE 2 (3,500 tons of ordnance delivered) is reached, landbased tacair begins to dominate, delivering more than 1,500 tons of ordnance per day, primarily CBU-97s.

Figure 3 on p. 42 provides a snapshot of the distribution of effort in MOE 3-attacks on revetted armor. The allocation of assets to this MOE commences on Day 9 (because we assume, for simplicity, that US air assets do not begin attacking revetted armor until the attacking force stops on all fronts). We assume that homing weapons, such as Maverick missiles or LGBs, are needed for effective attacks. F-15Es, F-16Cs, F-111Fs, and F/A-18C/Ds conduct these attacks. The F-15E and F-16, which deploy to the theater in large numbers and which have high sortie rates, score most of the kills. The threshold of 3,500 potential kills is reached on Day 16-seven days after these attacks commence.

Basic Conclusions

We performed a host of comparisons similar to those shown above, varying key assumptions. Specifically, we examined cases in which landbased air forces and seabased forces individually and in combination were denied access to bases and operating areas within 1,000 kilometers of the enemy, US forces fought two simultaneous theater wars, and different force structures were posited. Our conclusions are as follows:

• The contribution of landbased fighter-bombers to the theater campaign is not overly sensitive to assumptions about US access to bases close to the fight, provided sufficient tanker support is available. Heavy bombers, with inherent long range, are insensitive to variations in these assumptions.

• When the need to fight two simultaneous theater wars is considered, the results are similar to those seen in our single-war case, in terms of both relative distribution of effort and time required to achieve our thresholds. The total capacity of the airlift fleet and the portion of that capacity available to USAF deployments are crucial determinants of capability.

• In a Korean conflict, the presence of landbased fighters and fighter-bombers in Korea and Japan prior to the outbreak of war makes a substantial contribution to overall US combat capability and to our confidence in being able to defend Seoul.

• In most cases, changes in force structure (i.e., number of aircraft) had only minor effects on the achievement of objectives, provided that a robust landbased component was maintained. In extreme cases, relying solely on landbased assets resulted in only a one- or two-day delay in achieving objectives. Zeroing out the contribution of landbased bombers and fighter-bombers, however, added weeks-seventeen to eighteen days for MOE 1; nine to ten days for MOE 2; and forty to forty-two days for MOE 3.

• Failing to develop and procure modern munitions led to serious reductions in capability for all forces in MOEs 1 and 2.

• For the US to secure the capability implied by this work, it must have the use of mobile joint battle management systems and mobility forces in general.

A number of factors account for the dominant role of aviation in general, and landbased aviation in particular, in US power-projection capability-recent breakthroughs in sensors, miniaturized guidance, computing, and stealth. Perhaps more than any other single factor, the capabilities offered by modern munitions are a critical determinant of the overall capabilities of US power-projection forces.

IGPS bombs, such as the JDAM, can permit aircraft such as the B-2 and B-1, which today cannot deliver precision weapons, to do so. This capability, combined with a bomber’s large payload, can dramatically improve the capability of US forces to rapidly destroy an enemy’s fixed assets.

In addition to their use from carrier battle groups, cruise missiles will be essential for nonstealthy bombers to play a significant role in the early days of a theater war. Thus equipped, these bombers can destroy a large portion of an enemy’s fixed assets quickly, with very low risk of attrition.

Area antiarmor munitions, such as the Sensor-Fuzed Weapon (CBU-97 with Skeet submunitions), can give US air forces the capability to destroy columns of armored vehicles quickly. There is a guided version that can be used by bombers from high altitude.

It is essential to US strategy for theater warfare that the US retain the capability to airlift large quantities of military materiel over long distances. Given that the C-141 fleet is nearing the end of its useful life, the US must place a high priority on replacing the lift capacity of these aircraft.

Maritime prepositioning of munitions in southwest Asia and the western Pacific is absolutely essential for US power-projection capabilities. The munitions delivery capacity of two or three wings of USAF fighter-bombers is such that a substantial portion of AMC’s airlift fleet would be needed to keep a deployed force of this size supplied with munitions.

Increasingly, force effectiveness is limited mainly by incomplete information on the location and disposition of enemy forces and other assets. Further improvements in surveillance and assessment will be needed in order to fully realize the growing potential of modern airpower.

Munitions Loadouts and Sortie Rates

Force element

Destroy fixed target

(tons/sortie)

Halt invading armies (TMDs/sortie)

Destroy

dug-in forces (kills/sortie)

Average

sortie rates

B2-A

19

32

.5

B-1B

6(S/O)21

33

.5

B-52H

6(S/O)13

30

.25

F-117

2

.85

F-111F

4

12

1.3

1.12

F-15E

4

12

1.3

1.08

F-16

2

4

.9

1.26

A-10

3

4

.9

1.4

F/A-18C/D

2

4

.9

1.16

A-6E

3

4

1.3

1.06

AV-8B

1.5

2

.5

1.2

TLAM-C

.5

.98

reliability

TMD = Tactical Munition Dispenser

S/O = standoff

David Ochmanek, who currently works in the Office of the Secretary of Defense, worked until recently as an analyst at Rand Corp. While at Rand, he and John Bordeaux, another Rand analyst, wrote the paper “Comparing Air Power Projection Assets,” from which this article is adapted.