Stealth Bombers and the Indo-Pacific: Addressing Challenges, Expanding Capabilities

EXECUTIVE SUMMARY: In order to better address the challenges that a hypothetical large-scale armed confrontation with the People’s Republic of China would pose, the United States is actively bolstering its own military strength. This includes enhancing the capabilities of its B-2 stealth bomber force. The unique combination of long-range, persistence, large payload, and broadband, all-aspect low-observability makes the USAF’s stealth bomber force not only an indispensable asset in the event of conflict, but also an indispensable element of the country’s conventional and nuclear deterrent. The ongoing and planned upgrades to the B-2 force, the future introduction of the B-21, and the establishment of additional bomber forward operating locations in the Indo-Pacific region will ensure a much more flexible and robust conventional and nuclear deterrence posture vis-a-vis an increasingly powerful China.

Since debuting in combat over the Federal Republic of Yugoslavia during Operation Noble Anvil in 1999, U.S. Air Force (USAF) B-2A Spirit stealth bombers have participated in strikes against targets in Afghanistan (2001), Iraq (2003) and, more recently, Libya (2011 and 2017). While these strikes were conducted in low and medium-contested environments against adversaries with dated or negligible air defenses, the B-2A’s primary purpose remains conducting nuclear and conventional strikes in highly-contested environments against militarily-advanced opponents, and deterring these and other non-friendly actors from engaging in hostilities against the United States and its allies in the first place.

The U.S. 2017 National Security Strategy (NSS) identifies two present-day militarily-advanced competitors: China and Russia.^[i]Both are actively modernizing their armed forces, and both are geographically vast countries. In the event of major hostilities, conducting combat operations against these states would be particularly challenging. In order to better address the challenges that a hypothetical large-scale armed confrontation with the People’s Republic of China (P.R.C.) or the Russian Federation would pose, the United States is actively bolstering its own military strength. This includes enhancing the capabilities of its B-2A stealth bomber force. 

What follows is a non-exhaustive overview of these capabilities, specifically some of the ongoing efforts and future plans aimed at further strengthening the B-2A’s conventional long-range precision-strike role, as well as the challenges that these capabilities are meant to address.

The Indo-Pacific Range Challenge

In the event of conflict with China or Russia, B-2A bombers would be required to cover great distances to strike their targets. This is particularly true with respect to potential targets in the P.R.C. or the South China Sea, which lie further away from the continental United States than potential targets in Russia or Crimea. Similarly, B-2As flying sorties from bomber forward operating locations in the Indo-Pacific region would likewise have to cover substantially greater distances to reach probable targets in China or the South China Sea than they would flying sorties from RAF Fairford – a USAF bomber forward operating location in Europe – against probable Russian targets in, for example, Kaliningrad/Baltic region, Crimea, or the Moscow area.

While actual targets and flight routes will depend on a wide-range of considerations, for illustrative purposes consider the shortest approximate distances from Andersen Air Force Base (AFB) – a USAF bomber forward operating location on Guam – to areas housing the headquarters of the People’s Liberation Army’s (PLA’s) five theater commands, and to potential targets in the South China Sea. The distances (in nautical miles, rounded to the nearest hundred) are as follows: Nanjing (Eastern Theater Command), 1,800 nm; Guangzhou (Southern Theater Command), 1,900 nm; Shenyang (Northern Theater Command), 2,000 nm; Beijing (Central Theater Command), 2,200 nm; Chengdu (Western Theater Command), 2,500 nm; and the South China Sea, 1,600-1,900 nm.

The shortest approximate distances from Naval Support Facility (NSF) Diego Garcia in the British Indian Ocean Territory (BIOT) – another bomber forward operating location – to these areas are considerably greater: 2,600-3,000 nm to the South China Sea; 2,900 nm to Chengdu; 3,000 nm to Guangzhou; and 3,600-4,100 nm for the rest (rounded to the nearest hundred). Furthermore, although Diego Garcia lies closer than Guam to potential targets in the P.R.C.’s westernmost provinces, the shortest distance to many of these targets is still typically in excess of 3,000 nm.  

For comparison, according to Northrop Grumman, ‘a B-2 has an unrefueled combat radius of 3,000 nautical miles.’^[ii]An aircraft’s combat radius can, however, vary considerably from mission to mission depending on mission profile and payload. Differences in methods and data used for calculations have yielded widely divergent figures for the bomber’s unrefueled combat radius. One Air Force figure from the mid-1990s, for example, puts the B-2A’s unrefueled combat radius at 2,500 nm.^[iii]Similarly, a 2006 Congressional Budget Office (CBO) report, which estimates that a ‘fully loaded B-2’ has an unrefueled combat radius of ‘about 2,000 nautical miles,’ offers no elaboration on the assumed mission profile.^[iv]The report is also unclear as to what number was used for ‘full combat payload’ or which of the then-available weapons loadouts is this number based on. 

Thus, whether a B-2A would require in-flight refueling on a strike mission out of Andersen AFB against a given set of targets on the Chinese mainland will depend on its payload, route and mission profile. Potential targets in many areas of western China would require tanking support regardless of the above. As national security analyst Dr. Rebecca Grant notes in a 2007 Air Force Association report, ‘[i]n China, for example, Beijing is relatively near the coast. Reaching points in the interior of China, however, could add thousands of miles to a bomber’s route… Pre-strike and post-strike tanking over open ocean will be essential parts of the mission profile.’^[v]

Furthermore, though Andersen AFB’s relative proximity to the P.R.C.’s coastline and to the South China Sea makes it an important asset in the event of major hostilities, the base is also within reach of an increasing number of PLA conventional long-range precision-strike assets. As the Department of Defense’s 2019 China Military Power report warns, the PLA Rocket Force (PLARF) ‘continues to grow its [intermediate-range ballistic missile (IRBM)] inventories, including that of the DF-26,’ which is ‘capable of near-precision strike capability as far away from China as the second island chain.’^[vi]The report further warns that the PLA Air Force’s (PLAAF’s) H-6K medium-range bomber, which is capable of carrying long-range air-launched cruise missiles (ALCMs), is also ‘being fielded in greater numbers,” and allows the PLAAF to “engage U.S. forces as far away as Guam.’^[vii]Should Andersen AFB be put out of action, B-2 sortie rates would drop considerably as both NSF Diego Garcia and Whiteman AFB (the stealth bombers’ home base in Missouri) are significantly further away from the Chinese coast.

Expanding Forward Presence and Strike Range

Driven, in part, by concern over expanding PLA long-range precision-strike capabilities and the negative impact that they could have on bomber sortie rates from Guam, the Air Force has been evaluating additional forward operating locations for its stealth bomber force.^[viii]In August 2018, three B-2As embarked on the first rotational deployment of stealth bombers to Joint Base Pearl Harbor-Hickam in Hawaii.^[ix]Less than half a year later, in January 2019, the second such rotational deployment took place, likewise involving three B-2A bombers.^[x]Although substantially further away from the P.R.C. than Guam or Diego Garcia, Hawaii is nevertheless significantly closer than Missouri, allowing for much reduced flight times to and from potential Chinese targets.

A notable feature of the two rotational deployments to Hawaii was practicing ‘hot-pit’ refueling, whereby B-2 pilots kept their aircraft’s engines running while the aircraft was being refueled on the ground, enabling them to return back to the air within a very short period of time. As one USAF statement points out, during the first deployment, ‘[o]ne B-2 conducted hot-pit refueling at Wake Island, a coral limestone atoll in the mid-Pacific, west of Honolulu.’^[xi]Hot-pit refueling on Wake Island, which lies approximately 2,500 nm from China’s eastern coast and 2,850 nm from Beijing, is an important capability that could lessen reliance on in-flight refueling for bombers operating from Hawaii or Missouri in the event of conflict.

It is important to add that the USAF has also conducted brief deployments of B-2As to Australia as part of the bombers’ rotational deployment to Guam. The first such deployment took place in mid-2006 and included a B-2 engine running crew change at RAAF Base Darwin in Australia’s Northern Territory region.^[xii]Similarly, in 2016, an engine running crew change was conducted at RAAF Base Tindal, also located in the Northern Territory.^[xiii]Australia’s northern region is geographically well positioned to host a potential future rotational stealth bomber presence. Indeed, both RAAF Darwin and Tindal are, for example, closer than NSF Diego Garcia to China’s southern coast and to potential targets in the South China Sea. 

The establishment of additional forward operating locations for stealth bombers in Hawaii and, potentially, Australia, will enable an even more flexible and robust forward presence and power projection capability in the Indo-Pacific region. This is particularly true when considering that the USAF’s stealth bomber force will see a much needed expansion in size over the coming decades (a point discussed in greater detail in the last section), enabling more stealth bombers to be sent on rotational deployments. 

Apart from evaluating additional forward operating locations, the USAF will also extend the conventional standoff precision-strike capability of its B-2 force via the planned integration of Lockheed Martin’s AGM-158B Joint Air-to-Surface Standoff Missile – Extended Range (JASSM-ER).^[xiv]At Present, B-2As can already employ the baseline AGM-158A JASSM; a highly accurate, highly stealthy, subsonic ALCM that features a 1,000-pound class dual-mode penetrator and blast-fragmentation warhead for engaging high-value soft and hardened (including hardened, shallow buried) targets. The missile is equipped with a GPS-aided inertial navigation system (INS) for midcourse guidance, and an imaging infrared seeker (IIR) and autonomous target recognition system for terminal guidance.^[xv]

Whereas the turbojet-powered JASSM provides the B-2A with a standoff strike range of approximately 200 nm against fixed and relocatable targets, the turbofan-powered JASSM-ER will extend this figure to over 500 nm,^[xvi]allowing in-flight refueling to be excluded from certain missions. The extended-range variant will also enable a single B-2A to strike aimpoints located even further away from one another, potentially reducing the number of bomber sorties that may otherwise be required to cover certain targets located far apart. Once the missile is integrated on the B-2 force, the stealth bombers will be capable of carrying up to 16 JASSM-ERs each.

StormBreakers, Bunker Busters, and Improved Survivability

Among the many ongoing and possible future upgrades to the B-2 force are efforts and plans to integrate new precision-guided munitions that will enable standoff engagement of moving targets and will improve the bombers’ existing capability to destroy hardened structures, including hard and deeply-buried targets (HDBTs). Providing the B-2 force with these new/improved capabilities is increasingly important given that any hypothetical major conflict with a militarily-advanced adversary would necessitate the effective prosecution of large mobile and hardened target sets. Indeed, as former Deputy Assistant Secretary of Defense for Forces Transformation and Resources, Mark Gunzinger, notes in a 2010 Center for Strategic and Budgetary Assessments (CSBA) report, ‘[t]o increase the survivability of their assets… potential adversaries are making their targets mobile where possible and hardening and/or burying stationary targets.’^[xvii]China, in particular, has constructed numerous hardened structures,^[xviii]and fields large numbers of highly-mobile surface-to-air missile (SAM) systems and ballistic and cruise missile transporter-erector-launchers (TELs). 

To allow the B-2A to engage moving targets from standoff ranges, the Air Force intends to eventually integrate Raytheon’s GBU-53/B Small Diameter Bomb Increment II (SDB II) on the bomber.^[xix]The SDB II, now known as StormBreaker, is an advanced GPS-aided glide-bomb with an integrated tri-mode millimeter wave (MMW) radar, IIR, and semi-active laser (SAL) terminal seeker. It is designed to engage a wide range of fixed, relocatable and moving targets in poor weather conditions. StormBreaker is network-enabled, featuring a dual-band (Link 16 and UHF), two-way data-link that permits the launching platform, other aircraft, or a ground controller to provide the bomb with in-flight updates and retargeting.^[xx]It has a standoff range of over 40 nm when released from higher altitudes and features a multi-effects (blast, fragmentation, and shaped-charge jet) warhead for use against armored and non-armored enemy assets.^[xxi]

In response to growing adversary jamming capabilities, StormBreaker will also receive an Enhanced Anti-Jam (EAJ) Military Code (M-Code) GPS receiver.^[xxii]M-Code receivers and associated equipment will also be integrated on the B-2 force.^[xxiii]Numerous other munitions and platforms, including the aforementioned JASSM-ER, will get the new receivers as well.^[xxiv]

Weighing just above 200 pounds, SDB II is light and small enough to be carried by bombers in potentially very large numbers. Infact, in the early-2000s, the Air Force had intentions to integrate the 250-pound class Small Diameter Bomb Increment I (SDB I) on its B-2 force, anticipating that a single B-2A would carry as many as 192 SDB Is on a single sortie.^[xxv]By the late 2000s, however, the USAF decided to skip integration of the SDB I, which could not be used against moving targets, in favor of integrating the SDB II at a later date. A key motive for this decision was that earlier in the decade B-2As were upgraded to carry up to eighty 500-pound class Guided Bomb Unit-38s (GBU-38s) for use against stationary targets, allowing a single stealth bomber to hit up to 80 different aimpoints per sortie.^[xxvi]This greatly reduced the number of bomber sorties previously necessary to achieve the same effect against certain target sets. 

The Air Force therefore deemed it wiser to eventually integrate the SDB II, which would not only allow a large number of aimpoints to be struck on a single sortie, but would also allow engagement of moving targets.^[xxvii]The USAF has yet to specify when might the StormBreaker be integrated on the B-2A. The weapon recently completed operational testing on its threshold platform, the F-15E, and, according to the USAF’s fiscal year (FY) 2020 budget justification book, is expected to achieve initial operational capability on the fighter this year.^[xxviii]

As for enhancing the B-2A’s hard and buried target defeat capability, there are a number of efforts underway. Apart from the ongoing integration of the widely discussed B61-12 GPS-aided, variable-yield nuclear bomb on the B-2A (and related upgrades),^[xxix]work is also being done to improve conventional ‘bunker busting’ capabilities under a separate ongoing Air Force program known as the Hard and Deeply Buried Target Defeat System (HDBTDS) program. According to the Air Force’s FY 2020 budget justification book, this work includes an unspecified ‘primarily software-based’ modification to Boeing’s 30,000-pound class GBU-57 Massive Ordnance Penetrator (MOP) that is aimed at enhancing the ‘capability to hold additional [HDBTs] at risk in multiple Combatant Commands (COCOMs).’^[xxx]Like many other munitions, MOPs will also get the new M-Code GPS receivers.^[xxxi]At Present, the B-2A is the only platform capable of delivering the MOP in combat. Up to two MOPs can be carried by a single stealth bomber.

Another ongoing effort under the HDBTDS Program is the development of an improved 5,000-pound class conventional penetrator, currently known as the Advanced 5,000 lb (A5K) Peneterator. The penetrator will form part of a new integrated penetrator weapon system (smart bomb) that will also include a smart fuze system capable of detecting layers/voids, and a modified Joint Direct Attack Munition (JDAM) guidance tail kit.^[xxxii]The new A5K weapons system will offer superior performance against hard and buried structures compared to the existing GBU-28 series of 5,000-pound class precision-guided munitions. Flight testing of the new weapons system ‘against operationally representative targets’ is planned for FY 2020.^[xxxiii]The A5K JDAM will be integrated on the B-2A as part of the B-2 Expanded Strike program.^[xxxiv]

The B-2 Expanded Strike program will also include integration of the Hard Target Void Sensing Fuze (HTVSF). The HTVSF, as the USAF’s FY 2020 budget justification book explains, is a smart fuze system that ‘provides for in-flight cockpit programmability, safing and arming, multi-function (time delay and void sensing) and multi-delay arming capabilities.’^[xxxv]It is designed for use with 2,000 and 5,000-pound class penetrator weapons.^[xxxvi]

In the event of conflict, delivering bunker busters and other direct attack weapons (and, in some cases, standoff weapons), will require B-2A aircrews to navigate through hostile airspace protected by a modern integrated air defense system (IADS). To increase survivability when penetrating an adversary’s IADS, work is being done to upgrade the stealth bomber’s Defensive Management System (DMS) under the B-2 DMS Modernization program. Given the increasingly advanced air defense capabilities being fielded by China and Russia, this program constitutes an important upgrade to the B-2A force, particularly when considering that, as the USAF’s FY 2020 justification book notes, ‘[t]he current B-2 DMS was designed in the 1980s and has not received any upgrades to date.’^[xxxvii]

The DMS Modernization program, as the USAF’s FY 2018 annual acquisition report explains, ‘upgrades the threat warning systems onboard by replacing aging antennas, electronics, display system, and an autorouter, which automates the re-planning of aircraft missions in flight.’^[xxxviii]Thanks to the modernized DMS, B-2 aircrews will gain superior situational awareness and will be able to better avoid threats. Furthermore, as the budget justification book notes, ‘[t]he inherent increased sensitivity of the modernized DMS over the legacy system, with increased processing power, will build a battlespace picture that could be shared with joint force platforms by on-board communication systems.’^[xxxix]

Force Size: A Key Issue

The ongoing and planned upgrades discussed above, as well as the establishment of at least one additional stealth bomber forward operating location, will further enhance the potency of the B-2A force; however, a key issue remains: small fleet size. At present, the USAF’s stealth bomber force comprises just 20 B-2A bombers, only 16 of which are combat-coded.^[xl]Far from all are listed as mission-capable at any given point in time. Indeed, in the FY 2014 to FY 2017 period, annual mission-capable rates for the B-2A force averaged just 51-57%, increasing to about 61% in FY 2018.^[xli]Moreover, only a few bombers are kept in ‘pristine condition’ – that is, ready to conduct operations on short notice against targets protected by modern air defenses (the actual number of B-2s kept in this condition has varied, and, if required, can be increased during times of heightened tensions).^[xlii]

A key contributor to relatively low B-2 mission-capable rates is the need for extensive low-observable maintenance. B-2 low-observable maintenance includes, among other things, application of relatively delicate materials that can be damaged due to changes in atmospheric conditions.^[xliii]This is also why B-2As are, for the most part, only deployed to Andersen AFB, NSF Diego Garcia and RAF Fairford, all three of which are equipped with climate-controlled hangars for accommodating the stealth bombers. It is important to note that low-observable maintenance requirements have been considerably reduced as part of efforts under the ongoing B-2 Low Observable Signature and Supportability Modifications (LOSSM) program, whose purpose is to ‘enhance [low-observable] signature and/or improve aircraft supportability’ via the development of improved low-observable materials and structures, radio frequency diagnostic tools, evaluation systems and other relevant tools.^[xliv]However, given the total size of the B-2A force, the number of stealth bombers that are listed as fully or partially mission-capable at a given point in time remains small.

The B-2A is currently the only USAF platform that combines long-range, persistence and large payload with broadband, all-aspect low-observability. (Broadband stealth is essential for a penetrating bomber because an adversary’s IADS comprises both lower-band surveillance/acquisition radars and higher-band fire-control radars. All-aspect stealth is necessary because the orientation of the penetrating bomber with respect to adversary radars will vary as it navigates through hostile airspace). This unique combination of capabilities makes the B-2A a vital asset in the event of major hostilities with China given that the P.R.C. is geographically vast, fields modern air defenses and houses a vast number of potential targets. The small size of the B-2A force therefore represents a particularly acute issue.

Indeed, many potential targets located deep within the P.R.C. remain beyond the reach of non-stealthy aerial platforms or naval platforms equipped with conventional long-range standoff weapons. The longest range conventional standoff weapon presently fielded by the United States is the U.S. Navy’s Tomahawk Block IV (TLAM-E) sea-launched cruise missile (SLCM). According to official sources, it has a range of approximately 900 nm.^[xlv]The ranges of conventional ALCMs fielded by the USAF are significantly shorter than this. Moreover, due to their high cost, there simply aren’t enough conventional long-range standoff weapons to strike the vast number of potential targets in the P.R.C. Nor are existing conventional long-range standoff weapons suitable for prosecuting all target sets; hard and buried targets, for example, require heavier penetrators than those carried by long-range cruise missiles.^[xlvi]

A Qualitative and Quantitative Expansion of the Stealth Bomber Force

The introduction of Northrop Grumman’s B-21A Raider in the 2020s will mark the beginning of a quantitative and qualitative expansion of the USAF’s stealth bomber force. Like the B-2A, the B-21A will be a large, tailless ‘flying-wing’ bomber; however, as a result of certain design differences (notably, different inlet design and different trailing edge design) and advances in material science, manufacturing, simulation and modeling, the Raider will be stealthier.^[xlvii]The new stealth bomber is also likely to require significantly less low-observable maintenance. A prototype of the bomber is currently under construction and is expected to make its maiden flight in late 2021.^[xlviii]The USAF anticipates that the Raider will achieve initial operational capability in the ‘mid-2020s.’^[xlix]

The B-21A will have an open mission systems architecture, enabling easy integration of new subsystems.^[l]It willalso likely feature advanced sensors (including a modern active electronically scanned array (AESA) radar), modern communication systems for conducting net-centric warfare, and advanced sensor-fusion capabilities.^[li]Reportedly, the new bomber will also be optionally manned, with ‘unmanned operation possible several years after initial operational capability.’^[lii]

The B-21A will be capable of employing a large variety of weapons, allowing it to engage a wide range of target sets. No information is available on the new bomber’s payload capacity; nevertheless, it will likely be sufficiently large to allow carriage of one or two MOPs for attacking HDBTs.^[liii]Notably, the Raider will also be capable of carrying an unspecified number of highly stealthy Long Range Standoff (LRSO) ALCMs.^[liv]The LRSO is expected to achieve initial operational capability around 2030 and will be fitted with a nuclear warhead.^[lv]

No range figure for the LRSO is available; however, a range of about 2,500 km (1,350 nm) would allow it to strike almost any point in the P.R.C. when launched from a bomber over the ocean (Indian or Pacific, depending on target location).^[lvi]It remains unclear whether the USAF will eventually field a conventionally-armed variant of the new ALCM as well. A conventional LRSO would have shorter range than that of its nuclear-tipped counterpart, but greater than that of the JASSM-ER. Armed with conventional LRSOs, B-21As operating from more distant forward operating locations such as Diego Garcia and, potentially, Australia, would have a very large number of potential targets on the Chinese mainland within their reach without requiring in-flight refueling.

At present, the USAF plans to ‘acquire a minimum of 100’ B-21s.^[lvii]There are, however, concerns that this figure may not be sufficient, particularly when considering that the Air Force may retire its B-2As in the 2030s. In recent years, a number of authoritative studies have been published recommending the procurement of a larger number of B-21s at an accelerated rate. A 2018 report by The Mitchell Institute for Aerospace Studies, for example, concludes that the USAF ‘should aim to procure at least 180 B-21s at an increased production rate.’ Of these 180 bombers, 120 would be combat-coded.^[lviii]A 2019 CSBA report, meanwhile, assesses that over 100 B-21s would be required for major combat operations against the P.R.C. alone.^[lix]According to the report, the USAF should therefore aim for a total aircraft inventory of 288 B-21s (206 combat-coded), and likewise procure them at an accelerated rate.^[lx]

Given the vast number of potential targets that would need to be struck, and the vital role that stealth bombers would play in the early stages of conflict, it is essential for the Air Force to have both a sufficiently large inventory of Raiders, and an adequate number of bomber forward operating locations at its disposal in the region. Indeed, thanks to a combination of long-range, persistence, large payload and broadband, all-aspect low-observability, the B-21A, like the B-2A, will be an indispensable asset in the event of hostilities. As one 2019 Naval War College Review article notes, due to their unique combination of capabilities, ‘B-2s and B-21s would play a disproportionate role in the air war portion of any China-U.S. conflict.’^[lxi]Flying from forward operating locations in the Indo-Pacific region and from the continental United States, the stealth bombers would launch strikes on high-value targets in the South China Sea and the P.R.C., including China’s IADS (to clear the way for other aircraft) and targets located deep inside the country.    

The unique combination of long-range, persistence, large payload, and broadband, all-aspect stealth makes the USAF’s stealth bomber force not only an indispensable asset in the event of conflict, but also an indispensable element of the country’s conventional and nuclear deterrent. The ongoing and planned upgrades to the B-2A force, the future introduction of the B-21A, and the establishment of additional bomber forward operating locations in the Indo-Pacific region will ensure a much more flexible and robust conventional and nuclear deterrence posture vis-a-vis an increasingly powerful China.

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^[i]President of the U.S., National Security Strategy of the United States of America(December 2017) (accessed July 2, 2019).

^[ii]‘Value of Long-Range Strike,’ Northrop Grumman(accessed July 3, 2019).

^[iii]Bryan J. Benson, Transport Bombers. A Conceptual Shift in Precision-Guided Munitions Delivery(Maxwell AFB, AL: Air University Press, 1996), 10 (accessed July 3, 2019).

^[iv]Congressional Budget Office, Alternatives for Long-Range Ground-Attack Systems(March 2006), 3, 13 (accessed July 3, 2019).

^[v]Rebecca L. Grant, Return of the Bomber: The Future of Long-Range Strike(Arlington, VA: Air Force Association, 2007), 21-22 (accessed July 3, 2019).

^[vi]Department of Defense, Annual Report to Congress: Military and Security Developments Involving the People’s Republic of China 2019, E-1F4B924 (May 2019), 44, 47 (accessed July 2, 2019).

^[vii]Ibid., 41, 58.

^[viii]Joe Pappalardo, ‘China’s “Guam Killer” is Forcing B-2s to Practice Strikes from Pearl Harbor,’ PopularMechanics, October 9, 2018 (accessed July 5, 2019).

^[ix]Danielle Quilla, ‘First Hawaii deployment proves B-2 strategic flexibility to ensure free, open Indo-Pacific,’ U.S. Air Force, October 4, 2018 (accessed July 8, 2019).

^[x]Allen Palmer, ‘B-2 Bombers Deploy to Hawaii,’ Pacific Air Forces, January 10, 2019 (accessed July 8, 2019).

^[xi]Quilla, ‘First Hawaii deployment proves B-2 strategic flexibility to ensure free, open Indo-Pacific.’

^[xii]Mikal Canfield, ‘B-2 completes first deployment to Australia,’Pacific Air Forces, July 28, 2006 (accessed July 8, 2019).

^[xiii]‘B-2 Spirit crews perform engine running crew change in Australia,’ Pacific Air Forces, April 1, 2016 (accessed July 8, 2019).

^[xiv]U.S. Air Force, Department of Defense Fiscal Year (FY) 2020 Budget Estimates. Research, Development, Test & Evaluation, Air Force Vol-III Part 1(March 2019), 229 (accessed July 2, 2019); ‘Joint Air-to-Surface Standoff Missile-Extended Rage,’Lockheed Martin(accessed July 10, 2019).

^[xv]‘AGM-158 Joint Air to Surface Standoff Missile (JASSM)’ Dyess Air Force Base, February 28, 2011 (accessed July 10, 2019).

^[xvi]Ryan Hansen, ‘Air Force Introduces Next Generation Cruise Missile,’ U.S. Air Force, March 9, 2006 (accessed July 10, 2019).

^[xvii]Mark A. Gunzinger,Sustaining America’s Strategic Advantage in Long-Range Strike(Washington, DC: Center for Strategic and Budgetary Assessments, 2010), 27 (accessed July 11, 2019).

^[xviii]Sam Goldsmith, ‘U.S. Conventional Access Strategy: Denying China a Conventional First-Strike Capability,’ Naval War College Review72, no. 2 (Spring 2019): 6 (accessed July 11, 2019).

^[xix]U.S. Air Force, Department of Defense Fiscal Year (FY) 2020 Budget Estimates. Research, Development, Test & Evaluation, Air Force Vol-II(March 2019), 581 (accessed July 1, 2019); ‘GBU-53/B SDB II,’ available at Air Force Magazine(accessed July 17, 2019).

^[xx]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 581.

^[xxi]Office of the Director, Operational Test and Evaluation, Small Diameter Bomb (SDB) II(2016) (accessed July 17, 2019).

^[xxii]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 584.

^[xxiii]U.S. Air Force, Department of Defense Fiscal Year (FY) 2019 Budget Estimates. Aircraft Procurement, Air Force Vol-2 Mods(February 2018), 25 (accessed July 2, 2019).

^[xxiv]Michael Jones, ‘New military code about to board 700+ platforms,’ GPS World, April 9, 2019 (accessed July 11. 2019); U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-III Part 1, 553.   

^[xxv]U.S. Air Force, Long-Range Strike Aircraft White Paper(November 2001), 12 (accessed July 10, 2019).

^[xxvi]Marc V. Schanz, ‘SDB II Key to B-2 MTK Capability,’ Air Force Magazine, February 26, 2009 (accessed July 10, 2019); ‘Northrop Grumman Completes Deliveries of “Smart” Bomb Rack that Enhances Weapons Payload of B-2 Stealth Bomber,’ Northrop Grumman, March 28, 2006 (accessed July 10, 2019).

^[xxvii]Schanz, ‘SDB II Key to B-2 MTK Capability.’

^[xxviii]‘Raytheon StromBreaker Smart Weapon Completes Operational Testing,’ Raytheon, June 17, 2019 (accessed July 10, 2019); U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 581.

^[xxix]OrianaPawlyk, ‘Nuclear Gravity Bomb Completes First Qual Tests on B-2 Bomber,’ Military.com, June 30, 2018 (accessed July 12, 2019); For related upgrades, see U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-III Part 1, 232-233.

^[xxx]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 182.

^[xxxi]Ibid., 184.

^[xxxii]Ibid., 183.

^[xxxiii]Ibid., 184.

^[xxxiv]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-III Part 1, 232.

^[xxxv]U.S. Air Force, Department of Defense Fiscal Year (FY) 2020 Budget Estimates. Procurement of Ammunition, Air Force(March 2019), 126 (accessed July 2, 2019).

^[xxxvi]Vivienne Machi, ‘Air Force Moves Ahead with Void-Sensing Fuze,’ National Defense Magazine,February 28, 2018 (accessed July 15, 2019).

^[xxxvii]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 793.

^[xxxviii]U.S. Air Force, Fiscal Year 2018 Acquisition Report(2018), 22 (accessed July 5, 2019).

^[xxxix]U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-II, 793.

^[xl]Congressional Research Service, Air Force B-21 Raider Long-Range Strike Bomber, by Jeremiah Gertler, R44463 (October 2018), 9 (accessed July 20, 2019).

^[xli]Stephen Losey, ‘Fewer planes are ready to fly: Air Force mission-capable rates decline amid pilot crisis,’ Air Force Times, March 5, 2018 (accessed July 20, 2019; Stephen Losey, ‘Aircraft mission-capable rates hit new low in Air Force, despite efforts to improve,’ Air Force Times, July 26, 2019 (accessed July 26, 2019).

^[xlii]Rebecca L. Grant, ‘Promise Fulfilled,’ Air Force Magazine, February 2015, 46 (accessed July 20, 2019).

^[xliii]Kayla White, ‘Low Observable maintenance,” Whiteman Air Force Base, December 8, 2018 (accessed July 25, 2019).

^[xliv]Grant, ‘Promise Fulfilled,’ 47; U.S. Air Force, Research, Development Test & Evaluation, Air Force Vol-III Part 1, 233-234.

^[xlv]‘Tomahawk Cruise Missile,’U.S. Navy(accessed July 27, 2019).

^[xlvi]David A. Deptula and Douglas A. Birkey, Building the Future Bomber Force America Needs: The Bomber Re-Vector(Arlington, VA: Mitchell Institute for Aerospace Studies, 2018) 26-27 (accessed July 28, 2019).

^[xlvii]Dan Katz, State of Stealth(New York: Aviation Week Network, 2017), 35 (accessed August 1, 2019); Mark-Barret and Mace Carpenter, Survivability in the Digital Age: The Imperative for Stealth(Arlington, VA: Mitchell Institute for Aerospace Studies, 2017), 20, 30 (accessed July 28, 2019).

^[xlviii]John A. Tirpak, ‘B-21 to fly in December 2021; More B-52s to Come Out of Boneyard,’ Air Force Magazine, July 24, 2019 (accessed July 24, 2019).

^[xlix]U.S. Air Force, Air Force Global Strike Command Strategic Plan 2018, 23 (accessed July 8, 2019).

^[l]Congressional Research Service, Air Force B-21 Raider Long-Range Strike Bomber, 5.

^[li]Woodrow Bellamy III, ‘Northtop’s LRS-B Win Begins EMD Cycle for NexGen Bomber,’ Avionics International, November 4, 2015 (accessed August 1, 2019).

^[lii]Congressional Research Service, Air Force B-21 Raider Long-Range Strike Bomber, 4.

^[liii]James Drew, ‘New details emerge about LRS-B as contract announcement nears,’ Flight Global, September 4, 2015 (accessed August 3, 2019).

^[liv]U.S. Air Force, Air Force Global Strike Command Strategic Plan 2018, 23.

^[lv]Robin Hughes, ‘Boeing contracted to integrate LRSO cruise missile with the B-52H bomber, Jane’s 360, March 15, 2019 (accessed August 2, 2019).

^[lvi]See Dennis Evans and Jonathan Shwalbe, The Long-Range Standoff Cruise Missile and its Role in Future Nuclear Forces(Laurel, MD: Johns Hopkins University Applied Physics Laboratory, 2017), 6 (accessed August 2, 2019).

^[lvii]U.S. Air Force, Air Force Global Strike Command Strategic Plan 2018, 23.

^[lviii]Deptula and Birkey, Building the Future Bomber Force America Needs, 37.

^[lix]Mark A. Gunzinger et al., An Air Force for An Era of Great Power Competition(Washington, DC: Center for Strategic and Budgetary Assessments, 2019), 102 (accessed July 11, 2019).

^[lx]Ibid., 135.

^[lxi]Goldsmith, ‘U.S. Conventional Access Strategy,’ 16.

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