Conventional prompt global strike (CPGS) weapons would allow the United States to strike targets anywhere on Earth in as little as an hour. This capability may bolster U.S. efforts to deter and defeat adversaries by allowing the United States to attack high-value targets or "fleeting targets" at the start of or during a conflict. Congress has generally supported the PGS mission, but it has restricted funding and suggested some changes in funding for specific programs.
CPGS weapons would not substitute for nuclear weapons, but would supplement U.S. conventional capabilities. They would provide a "niche" capability, with a small number of weapons directed against select, critical targets. Some analysts, however, have raised concerns about the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional warheads and conclude that the missiles carry nuclear weapons. The U.S. Department of Defense (DOD) is considering a number of systems that might provide the United States with long-range strike capabilities.
The Air Force and Navy have both considered deploying conventional warheads on their long-range ballistic missiles. The Navy sought to deploy conventional warheads on a small number of Trident II submarine-launched ballistic missiles. In FY2008, Congress rejected the requested funding for this program, but the Navy has continued to consider the possibility of deploying intermediate-range technologies for the prompt strike mission. The Air Force and the Defense Advanced Research Projects Agency (DARPA) are developing a hypersonic glide delivery vehicle that could deploy on a modified Peacekeeper land-based ballistic missile—a system known as the conventional strike missile (CSM). In FY2008, Congress created a single, combined fund to support research and development for the CPGS mission. Congress appropriated $65.4 million for this program in FY2014, $95.6 million in FY2015, and $88.7 million in FY2016. The Obama Administration has requested $181.3 million for FY2017.
When Congress reviews the budget requests for CPGS weapons, it may question DOD's rationale for the mission, reviewing whether the United States might have to attack targets promptly at the start of or during a conflict, when it could not rely on forward-based land or naval forces. It might also review whether this capability would reduce U.S. reliance on nuclear weapons or whether, as some critics have asserted, it might upset stability and possibly increase the risk of a nuclear response to a U.S. attack. This risk derives, in part, from the possibility that nations detecting the launch of a U.S. PGS weapon would not be able to determine whether the weapon carried a nuclear or conventional warhead. Congress has raised concerns about this possibility in the past.
While most analysts expected the Air Force to take the lead in deploying a hypersonic delivery system on a modified ballistic missile—a concept known as the conventional strike missile (CSM)—tests of the hypersonic vehicle known as the HTV-2 have not succeeded. An alternative glider, known as the AHW, may be deployed on missiles based at sea. Congress may review other weapons options for the CPGS mission, including bombers, cruise missiles, and possibly scramjets or other advanced technologies.
Warheads deployed on boost-glide systems would not be affected by the 2010 New START Treaty because these are new types of strategic offensive arms. But those deployed in existing types of reentry vehicles on existing types of ballistic missiles would count against the treaty limits. This report will be updated as needed.
The George W. Bush Administration's interest in the use of conventional weapons for precision, long-range strike missions became evident in the 2001 Nuclear Posture Review (NPR). This study called for the integration of precision conventional weapons with strategic nuclear forces in a new category of "offensive strike" weapons.1 Several other Pentagon studies published during the Bush Administration also called on the United States to develop the capability to attack targets around the world, in under an hour, with conventional warheads. The Obama Administration, in the 2010 NPR, also emphasized the role that long-range, non-nuclear systems could play in supporting "U.S. regional deterrence and reassurance goals." The 2010 NPR indicated that conventional power projection capabilities were part of "effective regional security architectures,"2 arguing that these capabilities could help the United States assure and defend its allies, while reducing the role of nuclear weapons in U.S. security strategy.
In 2003, the Department of Defense (DOD) specifically identified a new mission—prompt global strike (PGS)—that sought to provide the United States with the ability to strike targets anywhere on Earth with conventional weapons in as little as an hour, without relying on forward based forces. DOD argued that this capability would bolster U.S. efforts to deter and defeat adversaries by providing the United States with the ability to attack high-value targets or "fleeting targets" that might be visible for only a short amount of time promptly, at the start of or during a conflict. DOD has considered a number of systems that might provide the United States with long-range strike capabilities. These include bombers, cruise missiles, ballistic missiles, and boost-glide technologies that would mate a rocket booster with a hypersonic glide vehicle. Congress has generally supported the rationale for the PGS mission, but it has restricted funding and suggested changes in the direction of specific programs. It is likely to continue to review the technologies and programs related to this mission as a part of the annual authorization and appropriations process.
During the George W. Bush Administration, analysts began to note that long-range ballistic missiles armed with conventional warheads would be an ideal weapon for this mission. They argued that these weapons, based in the United States or on submarines at sea, could attack targets worldwide with a high degree of precision in a short amount of time. However, during the latter years of the Bush Administration and the early years of the Obama Administration, DOD's programs began to focus on hypersonic weapons as the technology of choice for this mission.
Some analysts have questioned the need for these programs, raising concerns, for example, about the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional warheads and conclude that the missiles carry nuclear weapons. They have also questioned whether existing U.S. military capabilities might meet the need for prompt, conventional attacks in most potential conflict scenarios without raising the risk of miscalculation or misunderstanding.
The Navy and Air Force have each studied concepts and technologies that might contribute to the conventional PGS (CPGS) mission. The Army is also developing a hypersonic vehicle that might be deployed on long-range missiles. For several years, Congress funded programs managed by both the Navy and the Air Force. In FY2008, however, Congress combined the funding in a new defense-wide account that would explore a wider range of options for the prompt global strike mission.
This report provides an overview of the rationale for the PGS mission and the possible deployment of conventional warheads on long-range ballistic missiles or boost-glide systems in support of this mission. It then reviews the Air Force and Navy efforts to develop these systems. It summarizes congressional reaction to these proposals, then provides a more detailed account of the issues raised by these concepts and programs.
Throughout the Cold War, the United States maintained military bases overseas so that it could position its troops to deter, and if necessary, respond promptly to an attack from the Soviet Union or its allies. These forward bases were located, for the most part, in Europe and Asia—regions where conflict seemed most likely to occur. These overseas bases and forces were believed not only to increase preparedness, but also to deter conflict by their very presence in unstable regions. However, with the demise of the Soviet Union and the end of the Cold War, analysts argued that the United States must be prepared to fight in unexpected areas against a wide range of potential adversaries who may possess a great variety of military capabilities. Although the United States continues to deploy its military forces at bases around the world, it has begun to restructure, and, in many cases, reduce, its forces based overseas. It has also sought to improve its ability to move military forces into a region quickly when and if a conflict occurs. Moreover, as some observers have noted, the United States can no longer be certain that these bases are located close to the most likely areas of conflict.
As a result, many analysts and military officials have argued that the United States must maintain and enhance its long-range strike capability so that it can strike anywhere in the world with forces that are based in or near the United States,3 or with forces that have the range to reach targets across the globe from wherever they are deployed. This would not only allow the United States to pursue an adversary without relying on forward bases, it would also allow the United States to reach targets deep inside an enemy's territory if that area were out of the range of U.S. forces deployed at bases or on naval forces in the region. Moreover, if an adversary developed air defenses or other capabilities that could deny U.S. aircraft access to critical targets, a long-range strike capability based on ballistic missile technologies could prove valuable if launched early, as a "leading-edge" capability that degraded an opponent's defenses. Analysts argue that these types of systems would be far less sensitive to an adversary's anti-access and area denial (A2AD) efforts.
Further, some analysts argue that the United States must be able to attack targets across the globe in a matter of hours or less, either at the start of a conflict or during ongoing operations. This is because U.S. adversaries might adapt to the U.S. precision-strike capability by denying targeting information with concealment techniques or mobility, leaving the United States with little time to attack after it identified relevant targets. Moreover, many have noted that adversaries could seek to protect their assets by deploying them in buried or hardened facilities, leading to a requirement for improvements in the U.S. ability to defeat hardened and deeply buried targets promptly, before the adversary employed the hidden capabilities.
The need for prompt long-range, or global, strike capabilities has been addressed in general defense policy studies, such as the 2001, 2006, and 2010 Quadrennial Defense Review (QDR) Reports. The 2001 QDR noted that the U.S. defense strategy "rests on the assumption that U.S. forces have the ability to project power worldwide."4 The 2006 QDR expanded on the need for prompt global strike capabilities, noting that they would provide the United States with the ability "to attack fixed, hard and deeply buried, mobile and relocatable targets with improved accuracy anywhere in the world promptly upon the President's order." This QDR went on to call for the deployment of a prompt global strike capability, using Trident submarine-based ballistic missiles armed with conventional warheads, within two to four years.5 The 2010 QDR also noted that "enhanced long-range strike capabilities are one means of countering growing threats to forward-deployed forces and bases and ensuring U.S. power projection capabilities." It noted that DOD is pursuing a number of programs to meet this need, and, as a part of this effort, "plans to experiment with conventional prompt global strike prototypes."6
DOD has also addressed the prompt global strike mission in specific reports on Air Force doctrine, which have noted that "rapid power projection based in the continental United States has become the predominant military strategy." In May 2003, the Air Force issued a formal Mission Need Statement for the Prompt Global Strike (PGS) Mission. This statement indicated that the United States should be able to strike globally and rapidly with joint conventional forces against high-payoff targets, that the United States should be able to plan and execute these attacks in a matter of minutes or hours—as opposed to the days or weeks needed for planning and execution with existing forces—and that it should be able to execute these attacks even when it had no permanent military presence in the region where the conflict would occur.7
Officials in the Bush Administration viewed the prompt global strike mission as a means to extend the U.S. capability to address global contingencies that could threaten U.S. security and U.S. interests. For example, Admiral James O. Ellis, the commander of U.S. Strategic Command (STRATCOM) from 2002 to 2004, explained that PGS would "provide a wider range of options to the President in responding to time-critical global challenges."8 General James Cartwright, who served as commander of STRATCOM between 2004 and 2007, defined the global strike mission by stating that "it provides to the nation the ability to rapidly plan and rapidly deliver effect any place on the globe." The capability would not necessarily be nuclear, and a regional combatant commander could "tailor it for his target and deliver it very quickly, with very short time lines on the planning and delivery, any place on the face of the Earth."
General Cartwright also emphasized that the global strike capability involved much more than just the delivery of a weapon to a target, stating that "it encompasses both the ability to plan rapidly, to apply the precision to the intelligence and gather that intelligence in a very rapid manner, and then to apply that intelligence to the target and understand the effect we want to create."9 The intelligence requirements for the PGS mission could, however, prove quite demanding. General Michael Hayden, then the CIA director, noted in mid-2007 that the PGS mission will require "very convincing intelligence" before any attacks occur.10 He stated "If you are going to strike suddenly ... it has to be based on very powerful, very convincing intelligence." In addition, the intelligence may need to be released to the public, to demonstrate both the military need and time restraints that made the attack necessary. Moreover, most analysts agree that the United States does not yet have the capability to meet the intelligence demands of the PGS mission.
The Obama Administration's description of the prompt global strike mission focuses more on regional than global challenges. As was noted above, the 2010 QDR described the PGS mission as one possible means to address "growing threats to forward-deployed forces and bases and ensuring U.S. power projection capabilities." The 2010 Nuclear Posture Review similarly viewed PGS as an important component of U.S. regional deterrence capabilities when it noted that "these capabilities may be particularly valuable for the defeat of time-urgent regional threats."11
In October 2002, STRATCOM, which was in charge of plans and operations for U.S. strategic nuclear weapons, merged with U.S. Space Command (SpaceCom), which commanded military space operations, information operations, computer network operations, and space campaign planning.12 This merger gave the new STRATCOM the "ability to project power around the globe through space and information warfare." Further, in late 2002 and early 2003, the Pentagon restructured the new STRATCOM so that it could take on new missions, including the planning and execution of the prompt global strike mission.13 This change in the command structure highlighted the growing emphasis on long-range, strategic missions in conventional warfighting doctrine.
In July 2006, STRATCOM established its joint functional component command for global strike (JFCC-GS). According to its mission statement, JFCC-GS "is designed to optimize planning, execution and force management for the assigned missions of deterring attacks against the United States, its territories, possessions and bases." Among other tasks, it "provides integrated global strike capabilities to deter and dissuade threats and when directed, defeat adversaries through decisive joint global kinetic and non-kinetic combat effects."14
Analysts have identified a number of potential targets that the United States might need to strike promptly, either at the start of or during a conflict with a regional adversary.15 For example, if an adversary deployed air defense or anti-satellite weapons that could disrupt the U.S. ability to sustain an attack, the United States might choose to strike promptly at the start of a conflict with weapons that could penetrate and destroy the defenses. A prompt strike against an adversary's ballistic missiles or caches of weapons of mass destruction (WMD) might allow the United States to destroy these weapons before an adversary could use them. The United States might also use prompt, long-range weapons to attack an adversary's command and control capabilities, to degrade or undermine its operations early in a conflict.
The United States might also be faced with circumstances during an ongoing conflict when it would need to destroy targets that could appear quickly and remain vulnerable for short periods of time. These might include leadership cells that could move during a conflict or mobile military systems that the adversary had chosen to keep hidden prior to their use. These types of targets might only be vulnerable to weapons that the United States could launch promptly and direct to their targets quickly. Analysts have noted that PGS might provide the means to attack such targets if the United States did not have the necessary weapons located near the conflict.
The Defense Science Board outlined several of these potential scenarios in a March 2009 report prepared by the Task Force on Time Critical Conventional Strike from Strategic Standoff. This report "formulated five representative scenarios" that might require a "very rapid strike response to a developing situation."16 These scenarios included several cases.
Each of these cases provided scenarios where the United States might want to attack promptly at the start of, or during, a conflict with a regional adversary. However, as some analysts have noted, long-range prompt strike weapons may not always prove the best solution in all circumstances. Even if the weapon could arrive within a relatively short amount of time, the United States might not have the intelligence needed to pinpoint the target, particularly if it were moving. Moreover, an adversary might detect the launch of the weapon and move it before the weapon arrived. As a result, in some cases, a weapon that could loiter in or near the area of the conflict, and strike within minutes when the target became evident, may be better than a weapon that could launch promptly but might take more than an hour to arrive.17
The Obama Administration noted, in the 2010 NPR, that the Pentagon "is studying the appropriate mix of long-range strike capabilities, including heavy bombers as well as non-nuclear prompt global strike, in follow-on analysis to the 2010 QDR and the NPR." The United States might use a number of different weapons systems for this purpose. In the near term, these could include medium- or long-range aircraft, cruise missiles launched from bombers or submarines, and ballistic missiles based at sea or on land in the United States.18 But conventional aircraft, even if they are based near the theater of operations, could take several hours, or more, to reach their targets. Aircraft may also be vulnerable to enemy air defenses, particularly if they tried to attack targets deep inside enemy territory. Similarly, aircraft or cruise missiles based at sea may be too far from the theater of operations to strike critical targets in a timely manner.
As a result, many analysts have suggested that the United States should use long-range ballistic missiles (ICBMs and SLBMs) for the prompt global strike mission.19 During the Cold War, these long-range ballistic missiles provided the United States with the ability to threaten targets throughout the Soviet Union, and, if necessary, in other nations, from the United States or from submarines patrolling at sea. But these missiles have always carried nuclear warheads.20 To use them for the conventional prompt global strike mission, the United States would have to deploy these missiles with conventional warheads. The Bush Administration first raised the profile of long-range, conventional strike missiles in the 2001 NPR, when it introduced the concept of the "new triad." This concept joined long-range nuclear-armed missiles with precision-strike conventional weapons in a category called offensive strike weapons. The Bush Administration argued that the availability of precision conventional weapons would, possibly, provide the President with more options in a crisis, and, therefore, reduce the likelihood of the use of nuclear weapons.
The Pentagon's Defense Science Board (DSB), in a study published in early 2004, asserted that land-based long-range ballistic missiles have "unique, time-critical characteristics" that include "responsiveness, range, speed, precision, lethality, and freedom of maneuver."21 With these capabilities, they could attack targets anywhere in the world within an hour of their launch, without relying on forward bases or supporting military capabilities, such as the tanker aircraft needed to support long-range flights by bombers. They would not be at risk from air defenses, and there would be no risk to flight crews. Further, if the warheads could maneuver to slow their reentry and increase their angle of attack, they might be effective against some types of hardened and deeply buried targets. The DSB study asserted that these weapons could provide "a reliable, low-cost force on continuous alert with a high readiness rate and the capability to immediately react under strict control of the National Command Authority." In other words, the high levels of reliability, readiness, and command and control that were needed as a part of the U.S. strategic nuclear deterrent during the Cold War are also valuable characteristics for a long-range conventional strike system in the post-Cold War era.
In testimony before the Senate Armed Services Committee in April 2005, General James Cartwright, then the commander of STRATCOM, linked PGS to the "new Triad" concept advanced by the 2001 NPR. General Cartwright noted that "the New Triad concept will enable more precisely tailored global strike operations"22 by allowing the United States to choose conventional rather than nuclear weapons to attack some categories of targets. By replacing some nuclear weapons with conventional weapons in the U.S. strategic war plan the United States might be able to further reduce its reliance on, and, therefore, its number of deployed strategic nuclear weapons.23
General Cartwright and others emphasized that the substitution of conventional warheads for nuclear warheads in the U.S. war plan would require significant improvements in the accuracy of U.S. long-range ballistic missiles. If missiles could deliver their payloads more precisely to their targets, then, for some categories of targets, they may not need the explosive yield of a nuclear weapon to destroy the target. Both the Navy and the Air Force have explored advanced guidance and targeting technologies, such as the use of GPS (global positioning systems), to provide their missiles with these improvements in accuracy. This effort has been underway for more than two decades. After General Cartwright sought a study that would allow him to determine what proportion of the targets in the U.S. war plan could be attacked with conventional weapons, an industry analyst estimated that this proportion could be between 10% and 30% of the existing targets.24
In recent years, however, some analysts and military officials have questioned whether the United States should seek to substitute conventional warheads for nuclear warheads in the U.S. nuclear war plan. They note that conventional warheads may lack the deterrent capabilities of nuclear warheads, even if they could damage many targets, because they lack the psychological effects associated with nuclear weapons. According to General Kevin Chilton, the former commander of STRATCOM, this would not be a weapon that "engenders fear, compared to the threat of a nuclear strike." Instead, General Chilton and other analysts view long-range ballistic missiles armed with conventional warheads as a "niche" weapon that might be used to attack some critical targets in scenarios that would not have otherwise called for the use of nuclear weapons.25 In other words, instead of substituting for nuclear weapons, a new prompt global strike capability would expand the range of U.S. conventional options. For example, General Chilton noted, in 2008 testimony before the Strategic Forces Subcommittee of the House Armed Services Committee, that this type of weapon could "provide an additional arrow in the quiver, if you will, of the country to address emerging threats, that we might find a nuclear weapon application to be self-deterring to address that threat."26 Even without direct substitution, however, CPGS still might reduce U.S. reliance on nuclear weapons, because, with more conventional options, a President might be less likely to authorize the use of a nuclear weapon to attack a critical target.
The idea that long-range systems armed with conventional warheads could enhance deterrence remains evident in the discussion about a potential CPGS capability. In February 2012, James Miller, the Under Secretary of Defense for Policy, noted that programs like CPGS could help strengthen U.S. non-nuclear forces as a part of the U.S. deterrent.27 But, as has been evident in recent discussions, he referred to these systems' ability to enhance U.S. conventional capabilities rather than their ability to substitute directly for nuclear weapons.
Both the Navy and the Air Force have studied the possible deployment of conventional warheads on their long-range ballistic missiles in the past. The Air Force briefly studied the penetration capabilities of conventional ICBMs in the mid-1990s. In August 1995 it launched an ICBM armed with a "pointy" front end (and no explosive warhead) against a granite slab that had characteristics similar to reinforced concrete. Press reports indicate that the warhead entered the target at a 90 degree angle and penetrated to a depth of 30 feet, which is greater than the depth of penetration of any existing U.S. weapon.28 The Navy also sponsored studies in the 1990s that sought to develop a non-nuclear penetrating warhead for the Trident SLBM. These studies also focused on questions about whether a reentry vehicle from a ballistic missile could penetrate a hardened target, using only its speed and angle of reentry, without a nuclear explosion. Both the Navy and the Air Force recognized that, without a nuclear explosion, the reentry vehicle from a ballistic missile would have to be far more accurate than those deployed in the 1990s (and still deployed today) to attack and destroy a buried target.
In FY2003, the Navy requested funding for research on a new type of guided reentry vehicle that could significantly improve the accuracy of the Trident II (D-5) missiles. This program, known as the enhanced effectiveness (E2) initiative, included an initial funding request of $30 million, a three-year study, and a full-scale flight test in early 2007.29 Congress rejected the initial funding request in FY2003 and FY2004, but Lockheed Martin Corporation, the contractor pursuing the study, continued with a low level of research into this system.
The E2 reentry vehicle would have integrated the existing inertial measurement unit (IMU) guidance system (the system currently used to guide long-range ballistic missiles) with global positioning system (GPS) technologies so that the reentry vehicle could receive guidance updates during its flight.30 A standard MK4 reentry vehicle, which is the reentry vehicle deployed on many Trident SLBMs, would be modified with a flap-based steering system, allowing it to maneuver when approaching its target to improve its accuracy and increase its angle of penetration. This steering system, which the Navy referred to as a "backpack extension," would increase the size of the reentry vehicle, making it comparable in size to the MK5 reentry vehicle that is also deployed on Trident missiles. The E2 warhead could possibly have provided Trident missiles with the accuracy to strike within 10 meters of their intended, stationary targets. This accuracy would not only improve the lethality of the nuclear warheads but it would also permit the missiles to destroy some types of targets with conventional warheads.31
Lockheed Martin flew these reentry vehicles in test flights of Trident missiles.32 In a test conducted in 2002, it demonstrated that the new reentry vehicle could steer towards a target and strike with improved accuracy. In a test conducted in early 2005, a modified version of its reentry vehicle demonstrated that it could not only steer towards a target with improved accuracy, but also slow down and "control the impact conditions," capabilities that would be needed for the delivery of some types of conventional warheads to their targets. Lockheed estimated that, if the program received funding from Congress beginning in FY2006, its reentry vehicle could enter production in FY2010 and achieve an initial operational capability in 2011. The Navy, however, did not seek funding for this program in FY2004, FY2005, or FY2006.
The Lockheed Martin reentry vehicle became a part of the plan to deploy conventional warheads on Trident submarine-launched ballistic missiles, and was included in the Navy's budget request for FY2007 and FY2008. The budget request for FY2008 indicated that most of the work needed to design and develop the reentry vehicle for the conventional Trident could have been completed in FY2008, with an additional $20 million request planned for FY2009.33 The FY2008 funding would have supported, among other things, efforts to finalize the guidance and flap system on the maneuvering body extension of the reentry body, design an interface between the new guidance system and the missile system flight controls, begin development of a conventional payload that could fit within the reentry body, and initiate efforts to modify existing facilities so that they could test the conventional Trident modification (CTM) designs. Congress, however, rejected these funding requests amid concerns about the rationale for the program and the potential for misunderstanding if the weapons were used in a conflict.
If it had received the requested funding in FY2008, and proceeded with the expected work plan, the Navy planned to conducted system development and demonstration activities in FY2008 and FY2009, and planned to begin production and deployment in FY2010. With this timeline, the system would have reached its full operational capability by the end of 2012. However, as is noted below, Congress rejected the Navy's funding request for FY2008 and restructured the PGS program.
DOD allocated a portion of the combined funding for the PGS mission to this program area in FY2009. In documents submitted with its FY2009 budget request, the Navy sought funding for a 2009 flight experiment "using a Life Extension Test Bed (LETB-2) reentry body on a currently planned Trident D-5 missile test."34 The LETB-2 is essentially the same as the maneuvering reentry body, described above, that evolved from the E2 reentry vehicle program. Even though the test bed would fly on a Trident missile test, the Navy contended that the technology would be applicable to any conventional ballistic missile, and, therefore, was not prohibited by the FY2008 legislation. Moreover, according to some reports, the test was funded separately, outside the combined conventional prompt global strike (CPGS) account.35 DOD indicated that during FY2012, it would continue to adapt the LETB reentry bodies as a part of its test-range development plans.
The Navy also requested, in its FY2009 budget, funding for a reentry body for a conventional ballistic missiles. This program, known as the Medium Lift Reentry Body, would be too large to fit on a Trident missile, but could carry the warhead on the intermediate range submarine-launched ballistic missile described below. It would carry a tungsten-rod ("flechette") warhead, which would be designed to destroy area targets such as airfields and military bases.
The Navy began to speak publicly about its plans for the conventional Trident modification (CTM) in early March 2006. Under this concept, the Navy planned to deploy each of its 12 Trident submarines on patrol (two would be in overhaul at any given time) with two missiles equipped to carry four conventional warheads each. The remaining 22 missiles on each submarine would continue to carry nuclear warheads, and the submarines would continue to patrol in areas that would allow them to reach targets specified in the nuclear war plan, although the patrol areas could be adjusted to accommodate targeting requirements for the CTM. Only four submarines would be within range of their targets, with two in the Pacific Ocean and two in the Atlantic Ocean. Consequently, only eight conventional missiles would be available for use at any time, and only one or two of the submarines would likely be within range of the targets specified for attack with conventional ballistic missiles.36
The Navy considered two types of warheads for the CTM program in the near term. One warhead would be designed to destroy or disable area targets like airfields or buildings, using a reentry vehicle loaded with tungsten rods—known as flechettes—that would rain down on the target and destroy everything within an area of up to 3,000 square feet. The other might be able to destroy hardened targets, like underground bunkers or reinforced structures, if it were accurate enough to strike very close to the target. Each would be deployed within the reentry body developed and tested under the E2 program. The Navy also explored, for possible future deployment, technologies that might be able to penetrate to destroy hardened, buried targets.
The Navy argued that these warheads would have provided the Navy with the ability to contribute to the prompt global strike mission in the near term, a goal that was identified in the 2006 QDR. The report indicated that the Navy would seek to deploy an "initial capability to deliver precision-guided conventional warheads using long-range Trident" missiles within two years,37 although many expected it to take four years to field the full complement of 96 warheads. The capability, even when fully deployed, would be limited by the small number of available warheads. Hence, it seems likely that the Pentagon would have only planned to use these missiles in limited circumstances to meet specific goals.
The budget the Navy prepared for FY2007 included a total of $503 million over five years, with $127 million for FY2007, $225 million for FY2008, $118 million for FY2009, and $33 million for FY2010.38 As noted below, Congress denied the funding request in FY2007. The Pentagon requested a total of $175.4 million for FY2008, but Congress did not approve the specific funding again. Instead, as is noted in more detail below, it provided research and development funding for a more general category of "prompt global strike" initiatives.
The Navy has also studied the possible development and deployment of a submarine-launched intermediate-range ballistic missile (SLIRBM). It requested industry participation in the study in mid-2003, and planned to conduct two static test-firings of a prototype rocket engine in 2005.39 According to the Defense Science Board Task Force, this missile might have delivered a 2,000-pound payload over a 1,500-mile range,40 with an accuracy of less than 5 meters. This would allow the missile to reach its target in less than 15 minutes.41 Reports of the initial studies into this concept indicated that this proposed missile could carry either nuclear or conventional warheads, allowing it to contribute to the missions requiring prompt, long-range strike capabilities.42 These missiles could also be deployed on nuclear-capable Trident submarines, with 2 or 3 missiles deployed in up to 22 of the submarine's launch tubes, for a total of 66 missiles per submarine. However, as the concept emerged, it became evident that the missiles would have been deployed, with perhaps two per launch tube, in the four Ohio-class submarines that have already been converted to carry conventional cruise missiles and other non-nuclear weaponry.
Congress appropriated $10 million for the SLIRBM in FY2005 and $7.2 million in FY2006. In the House, the Defense Appropriations Subcommittee added $2 million for this effort in FY2007, but the conference committee provided only $1.3 million. The Pentagon did not request any additional funding for this program for FY2008, but it did indicate that prior-years' funding would be used to continue funding efforts that will demonstrate the affordability and feasibility of this concept.
The Pentagon remained interested in this concept in 2008, and considered allocating $120 million in FY2008 and $140 million in FY2009 to pursue a medium-range "Submarine-launched Global Strike Missile" with a range of 2,000-3,000 nautical miles.43 However, as is noted below, Congress eliminated Navy funding for conventional prompt global strike programs in FY2008 and combined all DOD funding in a single defense-wide account. This account did not provide any funds to this missile, and the Navy did not request any additional funds in its budget in subsequent years.
The Pentagon reasserted its interest in deploying a prompt strike capability on submarines in January 2012, in its report on defense budget priorities and choices. It noted that, as a part of the U.S. effort to "rebalance" U.S. forces towards the Asia-Pacific and Middle East regions, the United States would need to invest in capabilities "required to maintain our military's continued freedom of action in the face of new technologies designed to frustrate access advantages." The list of such technologies included the "design of a conventional prompt strike option from submarines."44 In his briefing after the release of this document, Secretary of Defense Leon Panetta linked this effort with a program to provide the Virginia-class attack submarines with the capability to carry more conventional cruise missiles. The same mid-body launch tubes, known as the Virginia payload module, that might carry more cruise missiles might also carry conventional boost-glide systems.45
DOD has not yet decided whether it will deploy a PGS system on land or at sea. However, it has left open the option of deploying the systems at sea, so that as it develops both the booster and the hypersonic glider technologies, it can pursue technologies that will reduce the cost and risk of the program even if they come with a reduced range. Moreover, unlike with the conventional Trident program, with an intermediate-range PGS system, DOD would not install conventional warheads on missiles that had been equipped with nuclear warheads. Moreover, they boosters would travel on a flatter trajectory, and would likely have different launch profile and a different number of stages, than the existing Trident missiles. According to General Martin Dempsey, the Chairman of the Joint Chiefs of Staff, these differences in technology would likely mitigate the risk of an adversary observing the launch and concluding, incorrectly, that the United States had launched an attack with a nuclear-armed missile.46
DOD budget documents demonstrate that it is moving forward with plans to conduct a test of conventional prompt strike system from a naval vessel. In its FY2015 budget request, DOD noted that, during FY2013, it began to review a new series of demonstrations within the Alternate Re-Entry System program area by the Navy's strategic systems program. It also stated that it would begin critical design reviews and begin to assemble a vehicle for a Navy flight test in FY2015. The FY2014 budget documents note that a flight test of Navy variant of a conventional prompt strike system, which could be a reference to the intermediate-range option deployed on Virginia-class submarines, might occur before the end of 2016.
This schedule has slipped, possibly as a result of the August 2014 flight test failure, but it remains in the plan for the CPGS program. In its FY2017 budget request, DOD indicates that it now plans to conduct a first Navy flight experiment in late 2017 and a second Navy flight experiment in 2019.
In 2003, the Air Force and DARPA (the Defense Advanced Research Projects Agency) initiated a program, known as FALCON (force application and launch from continental United States) that was designed to develop both a launch vehicle similar to a ballistic missile and a hypersonic reentry vehicle, known as the common aero vehicle (CAV) that, together, would provide the United States with the ability to meet the requirements of the prompt global strike mission.
The FALCON study outlined many of the requirements that would become part of the framework for the conventional prompt global strike mission. For example, it indicated that the proposed CAV, when launched by a modified ICBM or other launch vehicle, should be able to travel at five times the speed of sound (Mach 5) so that it could deliver a substantial payload from the continental United States to anywhere on Earth in less than two hours.47 The study identified a number of objectives for the CAV system that would allow it to achieve these goals. It stated that the CAV and its delivery vehicle should achieve alert status, which would make it ready to launch, in under 24 hours and should then be able to launch from this alert status in less than 2 hours, once it had received an execution order. The study indicated that CAV should then be able to reach its target within one hour of its launch.48 These characteristics would provide it with the capabilities needed to attack time-sensitive targets.49
To meet the "global" portion of the PGS mission, the study indicated that the CAV should not only have the range to "strike throughout the depth of an adversary's territory," it should also have a cross-range capability of 3,000 nautical miles. The cross-range measures the ability of the CAV to maneuver and vary from a standard ballistic trajectory after its release from its launch vehicle. This ability to maneuver would allow the CAV to adjust to new information so that it could attack mobile targets, if timely and accurate information became available and was communicated to the CAV during its flight. It would also provide the CAV with a high degree of accuracy, allowing it to deliver its weapons within a planned 3 meters of the intended target. The CAV would also have to be linked to "complete, timely intelligence, surveillance, and reconnaissance information."
To minimize the risk of ambiguity or misinterpretation, where a nation observing the launch might conclude it was under nuclear attack, the Air Force planned to segregate the missiles armed with conventional warheads and deploy them far from bases with nuclear warheads. The missiles could be deployed "on mobile launchers or in semi-buried silos or berms on each coast, ready to launch on short notice."50 The two potential bases included Vandenberg Air Force Base on the West Coast and Cape Canaveral on the East Coast.
Analysts have also identified a number of interrelated capabilities that the United States would need to be able to deliver weapons to targets across the globe within hours of a decision to launch. The United States would need the intelligence, surveillance, and reconnaissance (ISR) capability that would allow it to identify a target precisely and quickly. It would also need the command and control capability to review the targets, plan the attack, target the delivery vehicles, and order the launch within a short amount of time. Finally, it would need the continuing reconnaissance capability to verify that the intended target remained available and that the weapon reached and destroyed that target. The requirements would exist for both land-based and sea-based missiles.
As was noted above, the Pentagon's Defense Science Board (DSB), in a study published in early 2004, supported the idea of using long-range ballistic missiles for the prompt global strike mission because these missiles would have the required "responsiveness, range, speed, precision, lethality, and freedom of maneuver" to attack targets anywhere in the world within an hour of their launch.51 Moreover, the study went on to note that existing U.S. land-based ballistic missiles could be converted to carry conventional warheads. According to the DSB study, modified Minuteman II missiles might each be able to carry a single warhead that weighed between 500 and 1,000 pounds; a modified Peacekeeper could possibly carry between 6,000 and 8,000 pounds of payload, which would allow for multiple warheads or reentry vehicles.52 According to some estimates, these missiles could even destroy some targets without an explosive warhead, using the "sheer force of impact of a reentry vehicle moving at 14,000 feet per second."53 According to the DSB study, Peacekeeper missiles could also carry a single reentry body that had been modified to improve accuracy by allowing for the maneuverability of the warhead, like the E2 warhead described above.
In addition, as was noted above, the United States could use a hypersonic glide vehicle, like the CAV under consideration in the Falcon Study, as the reentry body on a long-range ballistic missile. According to the Falcon Study, the CAV would be an unpowered, maneuverable hypersonic glide vehicle capable of carrying approximately 1,000 pounds in munitions or other payload.54 This vehicle is a cone-shaped winged body that, after launch aboard a booster derived from a ballistic missile, would fly within the atmosphere at hypersonic speeds and maneuver to its target. As is noted below, DOD has funded this program through the defense-wide Conventional Prompt Global Strike (CPGS) program since FY2008.
The Air Force considered two types of warheads for the CPGS mission.55 One of these would contain kinetic energy projectiles, like the flechettes described above, that would be fused to disperse over a wide area after release from the payload delivery vehicle. The delivery body could also carry an explosive warhead to enhance its capability to penetrate and destroy hardened and buried targets. These munitions could be delivered by a hypersonic glide vehicle should such a system become operational. However, if the United States determined that it needed a conventional PGS capability in the near term, before the boost-glide technology was ready for deployment, these munitions might be deployed in existing reentry vehicles that follow a ballistic trajectory to their targets, like those currently deployed on U.S. nuclear-armed missiles.
In 2004, the Air Force indicated that it could modify both Minuteman II missiles and Peacekeeper (MX) missiles to carry conventional warheads. The Minuteman II missile was first deployed in 1965 and was retired in the early 1990s. The Air Force deployed 450 of these missiles. Each carried a single nuclear warhead and had a range of over 7,000 miles. The Air Force has already modified some of these missiles, using some as target vehicles in tests of missile defense technologies and a few in a space-launch configuration. The Peacekeeper missile was first deployed in 1986. The Air Force deployed 50 of these missiles; each carried 10 warheads and had a range greater than 6,000 miles. The Air Force deactivated these missiles between 2002 and 2005. It has now begun to modify these missiles and plans to use them not only for the PGS mission, but also to launch satellites.
The Air Force has renamed the modified Minuteman and Peacekeeper missiles, referring to them as Minotaur missiles. The Minotaur IV missile would use three stages from the Peacekeeper missile and a new fourth stage developed by Orbital Sciences Corporation. The Minotaur IV missile could serve as the boost vehicle for a land-based CPGS mission. When it began to consider the use of these missiles for the PGS mission, the Air Force stated that the modifications could be made at a relatively low cost and low level of technical risk because they would use the missiles' existing rocket motors. The avionics and guidance systems could rely, primarily, on existing technologies, with some modifications to allow the upper stages of the missiles and their reentry vehicles to maneuver for improved accuracy. The Air Force also indicated that a modified Peacekeeper missile would be able to carry much larger payloads than the Trident missile.56
The Air Force began an Analysis of Alternatives (AOA) study in 2006 to review technologies and programs that could meet the requirements of the prompt global strike mission. Reports indicate that the Navy and Air Force collaborated on the study, exchanging information on "service-specific" platforms, and considering a range of alternative platforms, across service lines, for the long-term PGS option.57 These include a long-range land-based option, a shorter-range forward deployed land-based missile, a sea-based option, and an air-breathing option. The Air Force completed this study in 2008.58
Congress eliminated funding for the Navy and Air Force PGS programs in FY2008. Instead, it created a combined, defense-wide Conventional Prompt Global Strike program (CPGS) that would pursue research and development into technologies that might contribute to the PGS mission. Congress appropriated $100 million for this program in FY2008, and indicated that DOD could not spend any of the funds in this account on the CTM program. Further, it specified that DOD had to allocate a portion of the funds to the Army program pursuing research into a hypersonic boost-glide vehicle. Details on the debates over funding are described below.
According to DOD, the CPGS program funds the design, development, and acquisition of guidance systems, boosters, mission planning capabilities, mission enabling capabilities, reentry systems, and payload delivery vehicles (PDVs). DOD may also use some of the funding for strategic policy compliance and research into advanced non-nuclear warheads.59 The key programs that have received support from these funds are the Air Force CSM, the DARPA/Air Force HTV-2 program, and the Army advanced hypersonic weapon (AHW).
As the AOA drew to a close in 2008, the Air Force began to pursue the development of a system known as the conventional strike missile (CSM). It initially expected this missile to serve as a mid-term follow-on to the conventional Trident modification (CTM) program,60 but after Congress refused to fund development of the CTM, the CSM became the earlier option for the PGS mission. Reports indicate that General Kevin Chilton, then the commander of STRATCOM, assigned the Air Force the lead role in developing the long-range missile capability for PGS in mid-2008.61 According to DOD, the CSM was, at that time, the "lead design to demonstrate a possible materiel solution for the CPGS warfighting capability gap."62
According to DOD, the CSM would be a land-based system that used boost-glide technologies to deliver conventional payloads at near-global ranges, and to provide effects on target within minutes to hours of launch.63 The CSM would not follow the standard ballistic trajectory of nuclear-armed ballistic missiles. Its booster would launch with a lower-profile, or depressed, trajectory. The payload delivery vehicle (PDV), after separating from the launch vehicle, could maneuver to its target. This would not only provide it with high accuracy, it would be able to maneuver to avoid overflight of third-party countries.64 With these capabilities, the CSM may mitigate some of the concerns about nuclear ambiguity raised by Congress during its review of the CTM program.
According to Air Force plans, the CSM would combine the Minotaur IV launch vehicle described above with a hypersonic payload delivery vehicle (PDV).65 Under recent plans the first PDV would be a weaponized version of the DARPA/Air Force HTV-2 vehicle. As an alternative, it could be based on the Army advanced hypersonic weapon (AHW) that is described below.66 Press reports indicate that General Chilton initially hoped that the CSM would reach an initial operational capability, with one missile on alert and two spares, by 2012. He later indicated that the missile might be ready for deployment in 2015.67 However, according to DOD officials, the program does not have an official deployment date, as DOD has not yet concluded the research, development, and testing programs for the possible reentry bodies. DOD will not even decide which technology will be deployed until the reentry bodies have been tested in five demonstration flights. This may not happen until later in the decade depending on progress in the testing program.68
DARPA indicated that the goal for the HTV-2 program is to develop a vehicle that can launch into the Earth's upper atmosphere and descend across the Pacific Ocean with speeds of more than 13,000 miles per hour. It should be able to travel from Vandenberg Air Force Base to a target near Kwajalein Atoll in the Pacific Ocean in 30 minutes. Lockheed Martin Corporation is developing the HTV-2, using many of the concepts and technologies developed for the E2 warhead.69 DARPA planned to acquire and test two vehicles. The Air Force also contracted with Lockheed Martin to produce a third vehicle, which the Air Force planned to use as the PDV in a test of the CSM's ability to deliver a weapon to the target.
In FY2008, when Congress established the defense-wide conventional prompt global strike program with a budget of $100 million, DOD allocated $56 million to hypersonic glide experiments and concept demonstration development. This is the portion of the budget that supports the development and testing of the HTV-2. This program area received an additional $42 million in FY2009 and $90 million in FY2010. The Obama Administration requested an additional $136.5 million for this program area in FY2011. According to DOD's budget request, it planned to use these funds to conduct the HTV-2 flight experiments, finalize design concept for the CSM payload delivery vehicle, complete qualification of a Minotaur launch vehicle for a CPGS mission, and mature/demonstrate technologies associated with the high speed demonstration of conventional munitions. DOD has also indicated that it would use funding in this program area to procure the PDV warhead and booster that the Air Force will use in the planned CSM "weaponized" flight test.70
On April 22, 2010, DOD conducted its first test of the HTV-2 vehicle, launching it from Vandenberg Air Force Base in California. It launched the HTV-2 on a Minotaur IV rocket, in its "lite" configuration, with only the three Peacekeeper stages, and without the new fourth stage. This reduced the range of the missile in response to test mission limitations.71 According to DARPA, its preliminary results show that the HTV-2 achieved controlled flight in the atmosphere before telemetry was lost nine minutes after liftoff.72 Media reports deemed the launch to be a partial success, noting that the boost mechanism performed a successful launch. The detachment was also successful, though the glider itself failed to fly the full time of 30 minutes and total distance of 4,100 nautical miles. According to press reports, DARPA was able to gather "a significant amount of data" during the test.73 DOD reviewed the results of the April 2010 test, in an effort to determine what caused the vehicle to fail during its flight.74 It also conducted a number of wind tunnel tests and computer simulations to optimize the vehicle design and flight trajectory before the second test.
DOD conducted a second test of the HTV-2 vehicle on August 10, 2011. According to DARPA, the Minotaur missile successfully boosted the HTV-2 vehicle onto the desired trajectory and the HTV-2 vehicle successfully separated from the booster and transitioned to its "Mach 20 aerodynamic flight." However, the HTV-2 then "experienced a flight anomaly post perigee." This prompted the system to make a "controlled descent and splash down in the ocean."75 In other words, DARPA lost contact with the HTV-2 vehicle after it began its independent flight along its glide trajectory, and the vehicle crashed into the ocean. DARPA said that the test had important successes, with the launching, separation, and initial trajectory of the vehicle, and that it collected significant data during the flight. However, it has not yet determined how to control the aerodynamic portion of the flight, after the HTV-2 separates from its booster.76
According to DOD, in FY2011, it completed a finalized the design concept for the CSM payload delivery vehicle and qualified the Minotaur launch vehicle for a CPGS mission analysis of launch system infrastructure requirements utilizing other ballistic missile propulsion programs. However, the combination of the poor test record and tight budget environment has undermined the future of this program. DOD allocated $51.8 million to this program area in FY2012 and requested an additional $49.5 million for FY2013. Congress added funding to the CPGS program area in FY2013; after sequestration, the budget totaled $176.4 million. However, only $23 million of this was allocated to the HTV-2 program. Further, in its FY2014, FY2015, and FY2016 budget requests, DOD sought only $2 million for this program area. According to the budget documents, these funds will allow DOD to conduct studies to evaluate system alternatives, and to continue aerodynamic and weapon risk reduction and technology maturation efforts through ground and wind tunnel tests. DOD does not, however, plan to conduct any additional flight tests of the HTV-2 vehicle.
The Army is also developing a hypersonic glide vehicle, known as the advanced hypersonic weapon (AHW). Like the HTV-2, the AHW would use a hypersonic glider to deliver a conventional payload, but could be deployed on a booster with a shorter range than HTV-2 and, therefore, may need to be deployed forward, on land or at sea. It would be based on a conical design, rather than the wedged-shape design of the HTV-2. Upon nearing a target, the weapon would be able to maneuver and home in on target using precision guidance system.
Congress appropriated $1.5 million for the Army's hypersonic glide body, now known as the advanced hypersonic, weapon in FY2006, and added $8.9 million in FY2007.77 DOD allocated $29 million of the combined fund for CPGS to the Army's program in FY2008, $13.9 million in FY2009, $46.9 million in FY2010, and $69 million for FY2011. Congress appropriated $91 million for this alternative in FY2012, and DOD requested an additional $42 million for FY2013. As was noted above, Congress increased CPGS funding in FY2013, and, after sequestration, the AHW portion of the budget received $147.8 million. Congress appropriated an additional $55 million for the AHW in FY2014, $90 million in FY2015, and $86 million in FY2016. The FY2016 budget documents also indicated that DOD expected funding to increase steadily in the next five years. Following this plan, DOD has requested $174 million for the AHW, now known as the Alternate Re-Entry System, and plans to request just over $1 billion between FY2017 and FY2021. The increase supports planned flight tests in 2017 and 2019.
The Army conducted a successful flight test of the AHW on November 17, 2011.78 The system launched from the Pacific Missile Range Facility in Hawaii, and used the strategic targets system (STARS) booster stack, which is derived from the Navy's Polaris ballistic missile. According to press reports, the vehicle traveled 2,400 miles, from the Pacific Missile Range Facility in Hawaii to Kwajalein Atoll. The test collected data on hypersonic boost-glide technologies and test range performance. The mission also tested the thermal protection technologies for the vehicle, an area where concerns exist because of the high temperatures generated during flight.
DOD initially indicated that the AHW program was a "risk mitigation effort in support of the Air Force CPGS project" and is intended to "develop and demonstrate the capability of an alternative payload delivery vehicle (APDV) through a two-flight test schedule." However, after the HTV-2 experienced difficulties in both its flight tests, and the AHW succeeded in its first test, this system appeared to be the leading contender for the hypersonic glider portion of a boost-glide conventional prompt strike system.
DOD conducted a second flight test of this system on August 25, 2014.79 During this test, DOD launched the vehicle from the Kodiak Launch Complex off Alaska and planned to fly it to the test range at Kwajelein Atoll in the South Pacific.80 However, controllers destroyed the weapon four seconds after launch after detecting problems with the STARS booster. With this failure early in the flight, the test provided no information about AHW glider and did nothing to advance the program.81 Reports indicate that the Army has determined that failure was caused by an "external thermal protective cover designed to regulate motor temperature," which "interfered with the launch vehicle steering assembly."82 Neither the booster nor the hypersonic vehicle contributed to the test's failure.
As a result, DOD plans to move forward with the test program for the AHW. It has now scheduled a flight experiment of a "scaled" version of the Advanced Hypersonic Weapon for 2017, with a second planned in 2019. According to the FY2017 budget request, DOD will use FY2017 funds to "finalize manufacturing and testing" of both hypersonic glide body and the booster that will be used in the first test. FY2017 funding will also support industry development of a booster for the second flight test test.
DARPA also, for a time, sought to design a new system, known as ArcLight, which could serve as an alternative delivery vehicle for the PGS mission. The ArcLight program would use "a high-tech missile based on the current standard missile 3 booster with a hypersonic glider that can reach more than 2,300 miles to its target."83 DOD budget documents from prior years indicate that the ArcLight missile would have a range of around 2,000 nautical miles and might carry a 100-200 pound payload. The vehicle would be launched from the Navy's Mark 41 vertical launch system, on both submarines and surface ships. It would have a shorter range than either the Trident missile or the Air Force CSM. As a result, it would require forward positioning of Navy assets. DOD requested $2 million for the ArcLight program in FY2010 and $5 million in FY2011. However, it seems to have terminated the program and has not requested any additional funding in FY2012.
Congress first considered the Administration's plans to develop conventional warheads for possible deployment on long-range ballistic missiles in FY2003. Since then, it has demonstrated some support for and some skepticism about the plans.
As was noted above, the Navy requested $30 million for its E2 program in FY2003 and FY2004. In each case, this was to be the initial year of funding in a three-year study. Congress refused the Navy's request in both years.
The Bush Administration requested $12.2 million in research and development funding for the common aero vehicle (CAV) program in FY2004. The House, in its version of H.R. 1588, the FY2004 National Defense Authorization Act, nearly doubled the authorized funding to $24.2 million. The Senate provided the requested amount, and the conference committee split the difference, authorizing $17.025 million. Although Congress supported the Administration's request for funding, the House had shown concerns about the possibility that U.S. launches of ballistic missiles armed with conventional warheads could be misinterpreted as non-conventional launches by nations who might monitor U.S. military activity—a concern, particularly, to Russia and China. Hence, the House required that the Air Force submit a report on the concept of operations for the CAV that would address questions about the potential for misinterpretation of the launches. This reporting requirement remained in the final version of the National Defense Authorization Act for Fiscal Year 2004 (P.L. 108-136).
The National Defense Authorization Act for Fiscal Year 2004 (P.L. 108-136, §1032) also contains a requirement for an annual report describing "an integrated plan for developing, deploying, and sustaining a prompt global strike capability." Congress mandated that the plan should include information on, among other things, the types of targets for long-range strike assets, the capabilities desired for these assets, an assessment of the command and control, intelligence, and surveillance capabilities necessary to support the PGS mission, integration with tactical missions, and cost and schedule for achieving the mission. In the conference report (H.Rept. 108-354), Congress noted that its interest in these issues derived from the 2001 Nuclear Posture Review and its focus on integrating nuclear and conventional strike capabilities to reduce reliance on nuclear weapons. It indicated that it saw a need for further analysis of future system requirements, along with a comprehensive effort to link planning and programs in a PGS roadmap to achieve a coherent force structure. Hence, although the Air Force considered the NPR objective of integrating nuclear and conventional strike forces as a separate mission and separate concept from PGS, Congress, initially at least, blended both into the request for a new report.
The Air Force submitted its report on the CAV concept of operations to Congress in February 2004. This report offered several suggestions for measures the United States could take to reduce the possibility of misinterpretation if the United States were to deploy, and employ, ballistic missiles with conventional warheads. Many of the measures discussed in this report are summarized below, under "Issues for Congress."
The Bush Administration requested $16.4 million for research and development on the CAV in FY2005. Congress again increased this funding level, appropriating $21.6 million for the development of the CAV. However, in July 2004, with passage of the FY2005 Defense Appropriations Act (H.R. 4613, P.L. 108-287), Congress repeated its concerns about the potential for misinterpretation. In the report on the Defense appropriations bill, Congress questioned whether there were safeguards in place to guarantee that other nuclear weapons states did not misinterpret the intent or use of ballistic missiles armed with CAV. In response to these concerns, the report stated that funds provided for CAV could only be used for non-weapons-related research on hypersonic technologies, including studies into microsatellites or other satellite launch requirements. Congress specified that the funds could not be used to "develop, integrate, or test a CAV variant that includes any nuclear or conventional weapons." Congress also indicated that the funds could not be used to "develop, integrate, or test a CAV for launch on any ICBM or SLBM." Congress would consider expanding the scope of this program in future years if safeguards negotiated among international partners were put into place.84
The Bush Administration requested $27.2 million for CAV in FY2006. In response to the restrictions in the FY2005 Defense Appropriations Act, it restructured the program, and redesignated the CAV as the hypersonic technology vehicle. This new program excluded any development of weapons capabilities for the CAV. Congress approved the requested funding in the FY2006 Defense Appropriations Act and did not impose any new restrictions. The Bush Administration requested, and Congress appropriated, an additional $33.4 million for CAV in its FY2007 budget. Congress also appropriated $12 million for the Air Force conventional ballistic missile (CBM) program, which was exploring the possible use of a modified Minuteman missile as a mid-term option for the PGS mission.
The budget projections in the FY2006 budget request demonstrated how costs could have increased if the Air Force continued to pursue the CAV program. The budget requests were projected to be between $31 million and $39 million each year for the next three years, but they were then projected to rise to $92 million in FY2010 and $94 million in FY2011. This sharp increase reflected an expected change in the program from research and development to production and deployment at the end of the decade. This change would require that the Air Force address and resolve congressional concerns about the potential for misunderstandings with the launch of ballistic missiles armed with conventional warheads.
The budget projection for the CAV also indicated that the CAV would not have provided a near-term solution to the PGS mission needs. It would not have been available until the middle of the next decade, even though, as was evident in the 2006 QDR, the Pentagon was interested in meeting the needs of the PGS mission in the near term. This resulted in a growing interest in the Navy's CTM program.
The Navy's FY2007 budget included $127 million for the conventional Trident modification. The request separated into three categories. The budget included $38 million for the CTM within the much larger ($957.6 million) budget for Trident II missile modifications; $12 million for strategic missile systems equipment to support the CTM; and $77 million for the development of an advanced strike capability that would demonstrate the feasibility of the CTM concept.
Neither the House nor the Senate Armed Services committees authorized the Administration's request in their versions of the FY2007 Defense authorization bills (S. 2766 and S.Rept. 109-254; H.R. 5122 and H.Rept. 109-452). Both committees noted their concerns about the possibility that nations, such as Russia, might misunderstand the launch of a conventional Trident missile and determine that they were under attack from U.S. nuclear weapons. Both committees requested reports from the Administration that would address a range of issues raised by this prospective program. The Senate Armed Services Committee withheld $95 million of the Administration's request, pending completion of the report. It authorized the use of $20 million for the preparation of the report and $32 million for research and development on technologies that would support the Trident modification. It specified that the money could not be used on the CTM program itself. The full Senate accepted the committee's position. The House Armed Services Committee eliminated the $38 million for CTM in the Trident II modification budget and the $12 million for strategic missile systems equipment. It also reduced by $47 million the Navy's request for funding for the CTM program, leaving $30 million for this effort.
The conference committee, in its report (H.Rept. 109-702, §219) adopted the reporting requirements included in the Senate bill, but, instead of fencing the funding pending completion of the report, accepted the House's reduction in CTM funding. Therefore, as was the case in the House bill, the conference report included only $30 million for research and development into an advanced strike capability that would support the CTM concept.
The House and Senate appropriations bills also rejected the Administration's request for funding for the CTM program. Following the HASC, the Defense Appropriations subcommittee in the House eliminated all but $30 million in research and development funding. It also raised questions about the feasibility of the proposed schedule for the program and questioned whether the decision to move forward immediately would pre-judge the outcome of the PGS AOA study. In the Senate, the Defense Appropriations Subcommittee eliminated all funding for the CTM program, and provided $5 million for the National Academy of Sciences to analyze the mission requirement and recommend alternatives. The conference report on the Defense Appropriations Act (H.Rept. 109-676) retained the Senate provision that funded $5 million for a report from the National Academy of Sciences. It also included $20 million in Research, Development, Test and Evaluation funds for research that would focus on those "developmental items which are common to all the global strike alternatives."
The President's budget request for FY2008 included continued funding of $32.8 million for the CAV. Congress did not approve this request, but in both the authorization and appropriations bills, transferred this funding to a new, integrated account for Prompt Global Strike Research. Congress also eliminated separate funding of $50 million for other elements of the FALCON program, rolling them into the new account as well. As is discussed in more detail below, the total funding for this new account was set at $100 million for FY2008, less than half of the requested funding for all the programs that were combined in the new account. The Pentagon has objected to this transfer, noting that the elimination of the specific line items and the overall reduction in funding would lead to the termination of the FALCON program and the cancellation of several planned flight tests for the CAV. Although the Pentagon eventually accepted the idea of a combined program for PGS research, it suggested that the total budget be set at $208 million, an amount equal to the total proposed for the combined programs, so that each could continue to receive the required level of investment.85 Congress did not accept this appeal, and the conference reports on both the authorization (H.R. 1585, H.Rept. 110-477) and appropriations (P.L. 110-116, H.Rept. 110-434) bills limited the funding to $100 million.
The President's budget for FY2008 also included a total of $175.4 million for the CTM program. This request included $36 million, within the much larger budget of just over $1 billion for Trident II modifications, to begin modifying the Trident II missiles to carry conventional warheads. Congress had denied all funding for this purpose in FY2007. It also included $13 million in strategic systems missile equipment, which would be used to begin modifying Trident submarines to carry the conventional missile. Congress had also denied this funding in FY2007. Finally, the budget included $126.4 million to develop advanced strike capabilities under the "Hard and Deeply Buried Target Defeat System Program" area. This funding is allocated to continue research and development into reentry vehicle technologies for the conventional Trident modification. Congress had appropriated only $20 million for this effort in FY2007, even though the budget had requested $77 million.
The House Armed Services Committee, in its version of the FY2008 Defense authorization bill (H.R. 1585, H.Rept. 110-146), supported continued research, development, testing, and evaluation of the conventional Trident concept, but prevented funds from being obligated or expended for the operational deployment of the system. Specifically, it approved the request for $126.4 million for continued research and development on the reentry vehicle, and authorized $16 million for procurement, but reduced the budget request by $33 million, withholding all funds for long-lead procurement. The Strategic Forces Subcommittee noted that it supported, in general, the pursuit of technologies for the prompt global strike mission, but also noted that questions remained about the concept of operations and the possibility for misunderstandings. Hence, it sought to slow the program until the National Academy of Sciences completed its report.
The Senate Armed Services Committee, in its version of the FY2008 Defense authorization bill (S. 1547, S.Rept. 110-77), recommended that no funding be provided specifically for the CTM program, and that all $208 million in PGS funding be transferred to PE 65104D8Z, to support common prompt global strike concepts. The committee specifically indicated that this program element should support a "coordinated look at a variety of kinetic non-nuclear concepts, as necessary, to address the feasibility of a prompt global strike." In its report, it noted that the services were exploring several potential options for the PGS mission, and that research funded through this program element could support, "in a coordinated fashion," technologies that could be common to several of these concepts. The committee also indicated that it believed any resulting PGS capability should be clearly and unambiguously non-nuclear.
The conference committee adopted the Senate's approach to combining the funding in a single account, but, as the Appropriations Committee had done, limited the funding to $100 million (H.Rept. 110-477). The conference report also required that the Under Secretary of Defense for Acquisition, Technology, and Logistics submit a plan describing how DOD would obligate the FY2008 funds (H.Rept. 110-477, §243). This funding profile indicates that Congress did not reject the Prompt Global Strike concept completely, even though it had not accepted the Administration's sense of urgency or its certainty in the need for the CTM program in the near term.
The House and Senate Appropriations Committees followed the "combined funding" model established by the SASC. The House Appropriations Committee eliminated the specific funding for the CTM, directed DOD to create a "prompt global strike program element within the Research, Development, Test, and Evaluation, Defense-Wide appropriation," and moved $100 million into this new account to "further the Department's prompt global strike initiative" without "limiting the Nation to a single option" at this point in time. Some of these funds could be used to support research and development on the CTM concept. The committee also mandated that DOD submit a report "that discusses the technology thrusts and investment objectives and outlines the allocation of funding towards achieving these objectives." The Senate Appropriations Committee, in its version of the bill (H.R. 3222, S.Rept. 110-155) provided $125 million for the Research, Development, Test and Evaluation, Defense-Wide account for prompt global strike mission. It noted that these funds should be used "for engineering and development of alternatives to the conventional TRIDENT missile program." The final version of the FY2008 appropriations bill limited the funding to $100 million (P.L. 110-181, H.Rept. 110-477).
The Pentagon requested $117.6 million for the prompt global strike program element established in the FY2008 Defense authorization and appropriations processes. It also submitted a report to Congress, as required by the FY2008 Defense authorization bill (P.L. 110-181, H.Rept. 110-477, §243), that outlined its plans for dividing up the FY2008 and FY2009 funding under the PGS program element. In this report, DOD planned to spend $58 million in FY2008 and $70 million in FY2009 on tests of the hypersonic glide vehicle emerging from the Air Force/DARPA program. It also allotted $30 million in FY2008 and $40 million in FY2009 for alternative reentry systems development, a reference to the Medium-Lift Reentry Body that could be deployed on a new sea-based ballistic missile. Further, the report indicated that DOD would spend $6 million in FY2008 and $3 million in FY2009 on the LETB-2 demonstration described above.
The House Armed Services Committee, following the lead of the Strategic Forces Subcommittee, approved this request. The Senate Armed Services Committee, however, added $30 million to this amount, for a total of $147.6 million, in its version of the FY2009 Defense authorization bill (S. 3001). It indicated that these added funds, plus an additional $15 million in the budget request, were to be allocated to R&D on the Army program developing an advanced hypersonic glide vehicle—this program had not been included in the original budget request. However, in the final version of the FY2009 Defense authorization bill, Congress provided the requested amount of $117.6 million for the PGS account.
The Defense Subcommittee of the Senate Appropriations Committee deleted $43 million from the PGS account, leaving $74.6 million. It removed the $40 million planned for work on the medium lift reentry body and the $3 million allocated to the LETB-2 test bed program. In other words, it rejected DOD's plans to continue developing reentry technologies that could be deployed on either the Trident missile or a new sea-based conventional ballistic missile. The final version of the Defense appropriations bill, which was included in a larger consolidated appropriations bill, included this reduction in funding. Further, the legislation specified that "not less than one-fourth" of the funds provided, or $19 million, must be "available" for the advanced hypersonic weapon under development by the Army.86
The Department of Defense requested $166.9 million for the defense-wide conventional prompt global strike program element. This request included $91.5 million for the DARPA/Air Force hypersonic test vehicle, which the budget indicated would support efforts to continue hypersonic technology development, to integrate the HTV-2 vehicles with Minotaur IV lite launch vehicles, and to assess the progress of thermal and aerodynamic protection to the vehicles. The budget request also included $46.9 million for the Army's AHW program. The budget documents indicated that this funding would support a first flight of the AHW in FY2011. Congress authorized and appropriated the requested funds for FY2010.
The Department of Defense requested $239.9 million for the combined Conventional Prompt Global Strike program area in FY2011. The budget documents indicate that the Air Force Conventional Strike Missile was still the leading design to fulfill the PGS mission, and the Army AHW was deemed the alternative risk reduction plan to the CSM. The FY2011 budget allocated $136.6 million to hypersonic glide experiments; this would support the continued development of a payload delivery vehicle (PDV) for the conventional strike missile and development of the Minotaur IV rocket booster. It would also support the integration of the HTV-2 delivery vehicle and Minotaur IV missile, with two test flights of this CSM design expected in FY2011. The budget also allocated $69 million to the Alternate Re-Entry System; this supports the development of the hypersonic glide body (HGB) or the Army advanced hypersonic weapon. The budget request would support one test flight of this technology in FY2011. The PGS fund also allocated $24 million to Test Range Development and $10.3 million to administrative and study costs, including the application of the Prompt Global Strike Analysis of Alternatives results.
Both the House and the Senate approved this request in their versions of the FY2011 Defense authorization bill. The Senate Defense Appropriations Subcommittee, in its report on the FY2011 Defense appropriations bill, recommended full funding for the FY2011 request; however, it directed that DOD could not obligate more than $189 million until it provided Congress with details how it planned to restructure the program in light of the disappointing flight test results for the HTV-2 vehicle.87 Congress, however, never completed work on the FY2011 budget request, passing, instead, a continuing resolution through March 4, 2011. This bill held funding for most government programs at the FY2010 level.
The Department of Defense has requested $204.8 million for conventional prompt global strike programs in FY2012. Although the original budget documents indicated that all of this funding is allocated to hypersonic glide experiments and concept demonstration, this was an error and some of the funding is alternative concepts and range support. According to the amended budget request, $132 million is allocated to hypersonic glide experiments and concept demonstration, while $51 million is allocated to the alternate payload delivery vehicle options, $12 million is allocated to range support and $10 million for long-range studies. The budget request indicates that the funding in FY2012 will be used to procure the PDV—the "weaponized" version of the DARPA/Air Force HTV-2 vehicle—the warhead, and the booster to support the planned "weaponized" test of the Air Force conventional strike missile.
When considering the Administration's request for the CPGS program, the House Armed Services Committee, in its version of the FY2012 Defense Authorization Bill, approved $179.8 million for this program. In its report, the committee noted that the HTV-2 vehicle had not succeeded in its 2010 test flight, and that it was concerned about DOD's intent to pursue a weaponized missile system, or any material development decision, before it had demonstrated that the technology is feasible. Moreover, the committee questioned DOD's narrow focus on the Air Force CSM with the HTV-2 payload as the solution to the CPGS problem. It noted that DOD had provided briefings about "other potential conventional long-range strike capabilities that may be lower cost, carry less technical risk, and provide a capability sooner than CSM."88 As a result, the committee encouraged DOD to pursue "a broader examination of the tradespace of CPGS capabilities and concepts to meet warfighter requirements." The Senate Armed Services Committee, in its version of the FY2012 Defense Authorization Bill, approved the Administration's request for $204.8 million for CPGS. The conference committee, however, adopted the House position, and authorized $179.8 million the CPGS program. It also altered the allotments within the budget, providing $61.8 million for hypersonic glide experiment and concepts development, the portion of the budget that supports the HTV-2, and $91 million for the Alternate Re-Entry System, which supports the Army's AHW program.
The House Appropriations Committee voted for a deep reduction in CPGS funding for FY2012, approving only $104.8 million for the program. The committee's report did not offer an explanation for the $100 million reduction. The Senate Appropriations Committee appropriated the requested $204.8 million. In the consolidated appropriations Act (H.R. 2055) for FY2012, Congress matched the Defense Authorization Act and appropriated $179.8 million for CPGS. The conference report noted that the reduction of $25 million was based on delays in the program caused by two failed HTV-2 flight tests. As a result, the conferees directed that the reduction in funding should not come from the AHW vehicle, which had a successful flight test in late 2011.
The Pentagon budget request for FY2013 included $110.383 million for the CPGS program. Within this total, DOD requested $49.5 million for hypersonic glide experiment and concepts development, $42 million for the Alternate Re-Entry System, $11 million for test range development, and $7.9 million for studies. The House and Senate Armed Services Committees both approved this amount in their versions of the FY2013 Defense Authorization Bills (H.R. 4310 and S. 3254); this amount was included in the final version of the FY2013 Defense Authorization Act (P.L. 112-239). The House Armed Services Committee, in its report accompanying the bill (H.Rept. 112-479), also directed the Secretary of Defense to provide a report "detailing how the Department plans to use competition and integrate verification and transparency measures as it develops and deploys CPGS capabilities."
The Senate Appropriations Committee, in its version of the FY2013 Defense Appropriations Bill, increased funding for the CPGS program from the requested $110.383 million to $200.383 million. In its report, the committee noted that the recommended an increase of $90 million so that the Army could continue planning for and completing a second, longer-range flight test of AHW. Congress included this amount in the Consolidated and Further Continuing Appropriations Act, 2013 (P.L. 113-6), although, after sequestration, the final amount appropriated for FY2013 equaled $176.4 million. Within this total, $147.8 million was allocated to the Alternate Re-Entry System, or AHW, and only $23 million was allocated to the HTV-2 hypersonic glide experiment and concepts development area.
The DOD budget request for FY2014 included $65.4 million for "prompt global strike capability development." Within this total, DOD allocated $2 million to hypersonic glide experiment and concepts development, $55 million to the Alternate Re-Entry System and warhead engineering, $5 million to test range development, and $3.4 million to studies.
A number of factors might account for both the reduction in the overall budget request and the striking shift away from the HTV-2 program area. First, the budget documents indicate that overall reductions in DOD spending have affected DOD's ability to develop prompt global strike capabilities. Specifically, DOD states that "the level of resourcing ... reflects iterative reductions from efficiencies and budget reductions, which reduces the Department's ability to develop flexible responsive solutions to emerging war fighter needs."89 The budget request also highlights a shift in defense priorities, noting that DOD now plans to focus, with higher priority, on "research and development of intermediate range concepts."90 This may be a reference to DOD's interest, as noted in the January 2012 report on Defense Budget Priorities and Choices, in designing "a conventional prompt strike option from submarines."91 As was discussed above, this option could lead to the deployment of intermediate-range ballistic missiles on Virginia-class attack submarines.
Within the CPGS program, the shift in funding away from the hypersonic glide experiment and toward the Alternate Re-Entry System indicates that DOD plans to seek an alternative to the HTV-2 vehicle. Specifically, according to the budget documents, the Alternate Re-Entry System "sub-project will test and evaluate alternative booster and delivery vehicle options and will assess the feasibility of producing an affordable alternate solution to fill the CPGS capability gap."92
Congress appropriated the requested funds, and maintained the requested division among program areas, in the FY2014 National Defense Authorization Act (P.L. 113-66). However, in its explanation of the bill, it requested that DOD submit a report addressing "the policy considerations concerning any potential ambiguity problems regarding the launch of a conventionally-armed missile from submarine platforms" and a description of the target sets that a submarine-launched missile could reach but that could not be reached by missiles from other platforms. It also requested that the report compare the costs of submarine-launched conventional missiles with the costs of those launched by other platforms. Congress included this provision because DOD's renewed interest in the possible deployment of a sea-based CPGS capability restored concerns about possible ambiguity issues.
The DOD budget request for FY2015 includes $70.8 million for Prompt Global Strike Capability Development. Within this total, DOD has allocated $2 million to the HTV-2 program—the Hypersonic Glide Experiment and Conceptions Demonstration Support—line and $65.2 million to the AHW—Alternate Re-Entry System/Warhead Engineering—line. The request also includes $3.6 million for CPGS studies, but no additional funding for test range development. The House and Senate Armed Services Committees both approved this amount in their versions of the FY2015 National Defense Authorization Act, but Congress added $25 million to the program's appropriation, for a total of $95.6 million.
As in FY2014, the "level of resourcing" in the budget request reflects "reductions from efficiencies and budget reductions." DOD notes that this "reduces the Department's ability to develop flexible responsive solutions" to meet CPGS requirements. At the same time, the FY2015 budget request follows the trend set in FY2013 and FY2014, with the reduced emphasis on the HTV-2 program and added funding flowing to the AHW glider program. Further, although this is not reflected in the budget request, during testimony, DOD officials have referred to the program as "conventional prompt strike," dropping the emphasis on global. Taken together, these two changes demonstrate that DOD's focus may now be on developing an intermediate range capability for the prompt strike mission.
The DOD budget request for FY2016 includes $78.8 million for Prompt Global Strike Capability Development. Within this total, DOD has allocated $2 million to the HTV-2 program—the Hypersonic Glide Experiment and Conceptions Demonstration Support—line and $72.95 million to the AHW—Alternate Re-Entry System/Warhead Engineering—line. The request also includes $2.9 million for CPGS studies and $1 million for test range development. This request, along with the plans to move forward with the testing program for the AHW, further indicates that DOD has essentially concluded the HTV-2 program and is moving toward the development and deployment of a system using the AHW glider and an intermediate-range booster, possibly deployed at sea.
The House, in its version of the FY2016 National Defense Authorization Act (H.R. 1735), provided $108.8 million for Prompt Global Strike Capability Development. It added $15 million for Concept Development by the Army of a CPGS option and $15 million for Concept Development by the Navy of a CPGS option. These additions were intended to support the program following testing complications in prior years. The House bill also contained a sense of the Congress statement noting that "the United States must continue to develop the conventional prompt global strike capability to strike high-value, time-sensitive, and defended targets from ranges outside of current conventional technology while addressing and preventing any risk of ambiguity." It mandated that the Secretary of Defense submit a report by September 30, 2020, on the outcome of the military requirements process and Milestone A decision for at least one conventional prompt global strike weapons system.
The Senate, in its version of the NDAA (S. 1376), authorized $88.8 million for this program area. In the report accompanying its bill (S.Rept. 114-49), the Senate Armed Services Committee noted that this funding was intended to support DOD's efforts to examine sea-based and ground-based concepts and to support the flight experiment scheduled for March 2017. The Senate bill also mandated that the Secretary of Defense make a Milestone A decision for the Conventional Prompt Global Strike Weapons System no later than September 30, 2020, or eight months after the successful completion of a second intermediate range flight test.
The conference report on H.R. 1735 adopts the Senate funding level, authorizing $88.8 million for Prompt Global Strike Capability Development, with an added $5 million allocated to Concept Development by the Navy and Concept Development by the Army. The report also adopts the House language with respect to requesting a report by September 30, 2020, on the outcome of the military requirements process and Milestone A decision for at least one conventional prompt global strike weapons system.
The DOD budget request for FY2017 includes $181.3 million for Prompt Global Strike Capability Development. Within this total, DOD has allocated $174 million to the AHW—Alternate Re-Entry System/Warhead Engineering—line. The request also includes $2 million for Hypersonic Glide Experiment and Concepts Demonstration Support, an activity that "supports both ground and flight tests" and provides data needed to support a potential acquisition program. The budget also includes $3.3 million for CPGS studies and $2 million for test range development. This request, along with the plans to move forward with the testing program for the AHW, further indicates that DOD is moving toward the development and deployment of a system using the AHW glider and an intermediate-range booster, possibly deployed at sea.
Congress approved the DOD request of $181.3 million for Prompt Global Strike Capability Development in the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328). It also mandated, in Section 1688, that the Secretary of Defense make a Milestone A decision for the program by September 30, 2020, or no later than eight months after the successful completion of the second intermediate-range flight test. The legislation also limits the funds available for the program to 75% of the authorized amount until Pentagon officials submit a report to Congress on whether there are warfighter requirements for a "limited operational conventional prompt strike capability" and whether the Pentagon's plan and schedule for the CPGS program supports those requirements. These provisions reflect congressional concerns about the pace and direction of the CPGS program.
When the Bush Administration first began to consider the deployment of long-range ballistic missiles with conventional warheads, some analysts argued that, with improvements in accuracy, conventional warheads could substitute for nuclear warheads in attacking some sites now targeted by nuclear weapons. This type of "substitution" would have allowed the United States to reduce its reliance on nuclear weapons and to reduce the number of nuclear weapons in its deployed forces. Critics of this rationale, however, noted that conventional weapons could not really substitute for nuclear weapons in U.S. deterrence strategy. Even if they had the accuracy and explosive power needed to destroy some types of targets, they could not threaten the scale of destruction and would not have the psychological effects of nuclear weapons. Most experts agree that these characteristics are necessary for the weapons to deter conflicts with other nuclear-armed nations.
As a result, most of the supporters of the CPGS mission now began to these weapons as a "niche" capability that would expand U.S. conventional options and reduce the likelihood that the President might need to use a nuclear weapon in the absence of a conventional alternative. The United States might only need a very small number of these weapons, for use against critical, high-value targets or as the "leading edge" of a broader military campaign. Moreover, the United States would plan for their use independent of its nuclear deterrent. The programs' advocates note that, in the absence of such a capability, in a circumstance when the United States believed it needed to strike promptly at long ranges at the beginning of a conflict, the President might have no choice other than to use a missile armed with a nuclear warhead. The CPGS capability would provide that choice. In the 2010 Nuclear Posture Review, the Obama Administration extended this logic to regional deterrence and the assurance of U.S. allies. If the United States had a wider range of credible conventional weapons that it could turn to when defending its allies and forces overseas, there could be fewer circumstances in which the United States might feel compelled to resort to nuclear weapons for regional deterrence. This would not only reduce the role of nuclear weapons in regional deterrence, it might also increase the credibility of the U.S. deterrent.
Some analysts have questioned, however, whether the President needs more options or flexibility when responding to threats to U.S. or allied security. The President has never, in the past, been faced with the choice of using a nuclear weapon or no weapon at all. The President has always had a wide range of conventional options, even if the United States had to wait hours or days for the weapons to arrive on target.
Many analysts have also argued that the deployment of CPGS might upset strategic stability and increase the likelihood of nuclear war. Although the U.S. President might choose to initiate a conflict or respond to a threat with a conventional attack, it is not clear that the adversary would know that the incoming weapons carried conventional warheads. Moreover, the United States would not be able to control the adversary's reaction or the escalation of the conflict, particularly if the adversary possessed nuclear weapons. Hence, by making the start of the war "easier" the deployment of conventional warheads on ballistic missiles might, in this view, actually make the eventual use of nuclear weapons more likely.
Russian officials have expressed a number of concerns about U.S. conventional prompt global strike capabilities and their implications for strategic stability.93 They have argued that these weapons, even if armed with conventional warheads, could threaten critical targets in Russia and even threaten Russia's strategic nuclear forces if the United States deployed large numbers of missiles armed with highly accurate reentry vehicles. This might provide the United States with the capability to undermine Russia's nuclear deterrent, without resorting to the first use of nuclear weapons, and might actually increase the likelihood of a U.S. attack against Russia. Moreover, even if Russia were not the target of an attack with these missiles, it might not know whether the missile carried a nuclear warhead or a conventional warhead, or whether it was headed towards a target in Russia. Finally, some Russians have argued that the United States might replace the conventional warheads with nuclear warheads to exceed the limits in a treaty.94
The PGS mission's requirements are based on the assumption that a future conflict would take place far from existing U.S. bases overseas, and possibly far from ocean areas where the United States has deployed most of its sea-based forces. They also assume that a future conflict could develop quickly, allowing too little time for the United States to move its forces into the region, either by acquiring basing rights on land or by moving sea-based forces closer to the theater of conflict. Further, the concern about hidden or relocatable targets reflects an assumption that targets could appear with little notice and remain vulnerable for a short period of time, factors that place a premium on the ability to launch quickly and arrive on target quickly. The requirements also assume that U.S. forces are likely to face an "anti-access" threat, or air defense capabilities that would impede operations by U.S. aircraft.
Many of these characteristics were present in Afghanistan in 2001, when the United States attacked al Qaeda training camps and the Taliban government after the September 11 terrorist attacks. The attacks on the United States came without warning, and, although the United States took several weeks to plan its response and acquire the needed intelligence information on target areas, speed was of the essence if the United States hoped to trap and destroy leaders at the training camps in Afghanistan. The United States had no military bases in the region, and had to take the time to acquire basing rights in nearby nations and to move U.S. naval forces into the region. Further, the mountainous terrain offered the enemy areas where their leadership could hide and hope to evade attack.
These characteristics, with the premium they place on prompt, long-range attacks, support the view that the United States should deploy new boost-glide capabilities to meet the requirements of the PGS mission. In this view, other weapons systems cannot address all the characteristics at the same time; bombers may be too slow to arrive and too vulnerable to air defense systems, sea-based or air-launched cruise missiles may also be too slow to arrive and of too short a range to reach remote targets, and sea-based systems, with the exception of long-range ballistic missiles, may also be too far away to reach high priority targets promptly at the sudden start of a conflict.
However, the presence of many of these characteristics in one recent conflict does not necessarily mean that they will all be present in most, or even many, future conflicts. While each is certainly possible, taken together, these characteristics describe a worst-case scenario that may occur rarely, or not at all, in its entirety. This observation highlights several questions that Congress could consider when reviewing the rationale for the PGS mission. How likely is it that the United States would face a sudden, unanticipated conflict, with no time to build up its forces in the region and with the requirement to strike some targets within hours of the start of the conflict? Would a delay of several hours or even days undermine the value of attacking these targets at the start of a conflict? Could other weapons systems provide the United States with the ability to "loiter" near the theater of operations, allowing a prompt attack during the conflict if hidden or concealed targets are revealed?95 A comparison of the likelihood of those scenarios that may provide the most stressing environments with the likelihood of less stressful scenarios may lead to the conclusion that other weapons systems can respond to many of these requirements in most circumstances.
Some Members of Congress and many analysts outside government have focused much of their criticism of the PGS concept on the potential that other nations might detect the launch of a U.S. CPGS missile and conclude, mistakenly, that the United States had launched an attack with nuclear-armed missiles. Specifically, some have argued that, if the United States were to launch these missiles during a conflict, nations with minimal satellite capabilities and launch notification systems (such as China) or degraded launch notification systems (such as Russia) could conclude that they were under attack with nuclear missiles.96 Further, because many possible targets lie south of Russia and China, and the United States has historically planned to launch its ballistic missiles over the North Pole, a conventionally armed long-range ballistic missile might fly over these two nations to strike its targets. For many minutes during their flight patterns, these missiles might appear to be headed towards targets in these nations. The potential for misunderstanding is compounded by the short time of flight of these missiles, giving these nations little time to evaluate the event, assess the threat, and respond with their own forces. Under such circumstances, critics claim that these nations may conclude they have no other option than to respond with their own nuclear weapons.
As was noted above, Congress raised concerns about the potential for misunderstanding in several of its annual debates over the authorization and appropriations of funds for the CPGS mission. These concerns grew as the Department of Defense planned to move ahead with the conventional Trident modification (CTM). In response to these concerns, in the FY2007 Defense Appropriations Act (P.L. 109-289), Congress provided $5 million for the National Academy of Sciences to analyze the mission requirement and recommend alternatives.
The National Academies published the report—U.S. Conventional Prompt Global Strike: Issues for 2008 and Beyond—in August 2008. This report recognized concerns about the potential for misunderstanding, but concluded that these concerns should not eliminate pursuit of the program. The study noted that the United States and Russia had monitored and tracked the launches of hundreds of ballistic missiles over the years, and they had demonstrated the capability to "acquire sufficient data to determine their trajectory and hence … their target."97 At the same time, the study noted that the risk of misunderstanding could increase if the United States used boost-glide technologies for the CPGS mission, because a nation's ability to predict the target of such a system would be undermined by the fact that these systems could maneuver and change their direction after launch. Moreover, the study noted that the use of new, conventional-only launchers or delivery vehicles would not necessarily mitigate the risks because "there is simply no 'bright line' between nuclear and conventional systems when relatively long-range platforms are being considered."98
The National Academies study noted that concerns about the possible misinterpretation of a launch were, however, limited at this time to Russia, because no other nuclear weapons state has the ability to detect and track the launch of U.S. ballistic missiles.99 As a result, the United States might be able to mitigate the risks of misunderstanding by altering the deployment and operating patterns of systems armed with conventional warheads, and by cooperating with Russia to demonstrate that these systems do not carry nuclear warheads.
For example, the Air Force indicated during its early studies that it could deploy missiles armed with conventional warheads at bases, such as Vandenberg Air Force Base on the California coast, that did not house missiles armed with nuclear weapons. According to the Air Force, "the new coastal basing sites would have no nuclear capability or association,"100 as they would lack the facilities and equipment needed to handle or store nuclear weapons. The United States could then declare, to Russia or other nations, that these systems were equipped with conventional warheads. This declaration would further demonstrate that the missiles at the two coastal bases were different from nuclear ICBMs, even though it would not preclude the possible covert deployment of nuclear warheads on the missiles.101 Further, their deployment with a hypersonic reentry body, rather than a standard post-boost vehicle and warhead present on a nuclear-armed missile, would reinforce this designation.102
The United States and Russia could also institute a number of cooperative measures to add confidence to the U.S. declaration that the missiles deployed at coastal bases would carry conventional warheads. These measures could include military-to-military contacts, high level political consultations, and ongoing discussions to keep Russia informed about U.S. plans for these missiles and to make them aware of the observable differences between conventional and nuclear ballistic missiles.103 The United States could also invite other nations to observe test launches of these missiles or to participate in exercises that include simulations with these missiles. This might allow nations such as Russia to become familiar with the operational procedures associated with the CPGS missiles and to distinguish between these procedures and those associated with nuclear-armed missiles. Further, the United States could allow Russia to conduct short-notice inspections at these bases to confirm the absence of nuclear weapons either on the missiles or in the storage facilities.104 Over time, these measures would not only provide information about the missiles and their missions, but might also build confidence and understanding between the parties. The increased level of cooperation, and possibly decreased level of suspicion, might then reduce the likelihood of misinterpretation if the United States were to launch ballistic missiles with conventional warheads.
The United States could also provide Russia with prior notification of planned launches of ballistic missiles with conventional warheads, or the two nations could set up a dedicated "hot line" for use after a launch. That way, the United States could inform Russia of the launch and assure it that the missile did not carry a nuclear warhead and was not headed for targets in Russia. In addition, as has been discussed on many occasions over the years, the United States and Russia could share early-warning data at a joint facility so that Russia would have the information it needed to distinguish between the launch of a nuclear-armed ballistic missile from a northern base and the launch of a conventional-armed ballistic missile from a coastal base.
The Air Force also indicated that the CSM, which would use a conventional booster and a hypersonic payload delivery vehicle, would not follow the same trajectory as a nuclear-armed ballistic missile. Specifically, the Air Force plans to launch the CSM on a "depressed trajectory" that would achieve an altitude of only 500,000 feet. As a result, its flight would not resemble the trajectories that would be followed by nuclear-armed ballistic missiles on course for targets in Russia or China.105
DOD has indicated that the same would be true of a submarine-launched, intermediate-range boost-glide system. It would follow a shaped or depressed trajectory, and would not resemble the launch characteristics or trajectory of a nuclear-armed ballistic missile. Moreover, if the missile used a new booster, rather than one that had been deployed as a part of the U.S. nuclear force, the difference would likely be evident to Russia's early warning systems.
Taken together, these three types of measures might help reduce the risks of misunderstandings. But the accumulation of information during peacetime and frequent communications during crises may not be sufficient to address problems that could come up in an atmosphere of confusion and incomplete information during a conflict. Specifically, the argument in favor of using long-range ballistic missiles for the PGS mission assumes that the United States might have little warning before the start of a conflict and might need to launch its missiles promptly at that time. This scenario would allow little time for the United States to consult with, or even inform, other nations about its intentions. If other nations are caught by surprise and fear they might be under nuclear attack, they might also decide to respond promptly, before the United States had the opportunity to convince them that the missiles carried conventional warheads.
Even though routine data exchanges and on-site inspections may provide confidence in the absence of nuclear warheads on the missiles on a day-to-day basis in peacetime, they cannot provide assurances that the warheads could not be changed in a relatively short period of time or that the warheads were not actually changed in the days or weeks since the last inspection. In addition, changing the basing patterns or launch patterns of missiles to draw a sharper distinction between conventional and nuclear-armed missiles assumes both that other nations can observe the differences and that they believe the different appearances indicate different warheads. Finally, these measures would do nothing to alleviate concerns among nations that did not participate in the cooperative programs.
As a result, while the measures described above can reduce the possibility of misunderstandings, they probably cannot eliminate them. Moreover, they cannot address concerns, often expressed by officials in Russia and China, that the United States might use these weapons, along with other conventional strike systems and missile defenses, to acquire a the ability to attack strategic or nuclear targets in these nations without resorting to the use of U.S. nuclear weapons.
As the preceding discussion indicates, the United States has considered a number of alternatives for weapons systems that could contribute to the PGS mission. For a time, the Air Force CSM, armed with a payload delivery vehicle derived from either the DARPA/Air Force HTV-2 vehicle or the Army AHW vehicle, appeared to be the main contender for this mission at the present time. However, because the HTV-2 has not had a successful test flight and the AHW, which has tested successfully, may be better suited to an intermediate-range system, a submarine-launched missile armed with either a guided warhead or the AHW may now be the leading contender for the conventional prompt strike mission. But these are not the only options for precision, conventional strike weapons, particularly if a system with shorter range or longer delivery times can meet some of the requirements. As a result, while reviewing Administration requests for funding for the conventional prompt strike mission, Congress could consider a range of alternative weapons systems.
Long-range land-based ballistic missiles armed with conventional warheads, even if they relied on standard ballistic missile reentry bodies instead of boost-glide technologies, would likely possess many of the operational strengths associated with nuclear-armed ballistic missiles. They might have extremely high rates of readiness and reliability, allowing military planners to expect more than 90% of the missiles to be available for use at any given time; they could likely respond promptly after a decision to launch; and, when armed with a hypersonic payload delivery vehicle, they would likely have a high degree of accuracy allowing for attacks across a wide range of targets. Consequently, these systems would "free the U.S. military from reliance on forward basing and enable it to react promptly and decisively to destabilizing or threatening actions by hostile countries and terrorist organizations."106 These weapons would probably address all the potential circumstances cited in requirements for the PGS mission.
However, as is noted above, many analysts have expressed concerns about the possibility that the launch of these missiles could generate misunderstandings within other nuclear-armed nations and undermine strategic stability because they would follow the same ballistic missile trajectories as U.S. nuclear-armed missiles. Even if the United States based and operated these missiles differently from nuclear-armed missiles and cooperated with other nations to demonstrate that these missiles did not carry nuclear warheads, other nations, such as Russia or China, could still question whether the missiles launched during a conflict carried conventional warheads or whether the United States had converted them back to carry nuclear warheads.
Submarine-launched ballistic missiles armed with conventional warheads could have many of the same benefits as land-based missiles. As nuclear delivery vehicles, they have been deployed with the command and control systems needed to allow for prompt decision making and prompt launch during a crisis. They have the range to reach targets around the world and they could have the accuracy, particularly if armed with hypersonic payload delivery vehicles, to attack a wide range of targets on short notice.
SLBMs armed with conventional warheads, however, would also raise many of the same questions about misunderstandings as land-based ballistic missiles, particularly if these warheads were deployed on the same submarines that currently carry nuclear warheads. The Navy could not employ many of the techniques identified by the Air Force to convince potential adversaries that the missiles carried conventional warheads. Even if the United States did deploy SLBMs with conventional warheads on submarines that did not carry nuclear warheads, it would be extremely difficult to demonstrate these differences and assure other nations of the segregated deployments in a submarine that is intended to be hidden and invulnerable when at sea. Further, according to some reports, Russia's ability to monitor U.S. SLBM launches is even more degraded than its ability to monitor ICBM launches, so it might conclude that it is under nuclear attack if it observed an SLBM launch from a U.S. ballistic missile submarine.
On the other hand, because the submarines are mobile and the missiles are long-range, the United States could alter the patrol areas for Trident submarines so that, if they were to launch their conventional missiles, they could use trajectories that did not require them to fly over these nations on their way to their intended targets. Alternatively, the submarines could move prior to launching their missiles, to avoid overflight of Russia or China, but this presumes that the United States had the time to move its submarines to these new launch points prior to the start of the conflict, a possibility that is inconsistent with the PGS mission's assumption that the United States could need to launch its missiles promptly at the start of an unexpected conflict.
An intermediate-range submarine-launched ballistic missile could achieve many of the objectives necessary for the PGS mission. It could attack targets quickly, both at the start of a conflict if the submarines were within range, and during the conflict if new targets emerged. Its speed and angle of attack might also make it capable of attacking some types of hardened or buried targets. It might also be able to penetrate an adversary's defenses without putting aircraft or crews at risk. In addition, by launching from submarines based close to the theater of conflict, these missiles might avoid some of the overflight problems that would occur if a ballistic missile launched from the continental United States. It would not eliminate all possibilities of misunderstanding, however, because nations observing the launch might not be able to tell whether the missiles carried nuclear or conventional warheads, and, with the short time of flight, they might decide to assume the worst. Nevertheless, Navy officials have stated that there would be "immediate observable differences at launch" between this missile and a Trident missile because this missile would use two, rather than three, stages and would deliver a single reentry body and warhead, while the Trident missiles can carry up to eight warheads.107 Further, the warhead under development for this missile would be too tall to fit on a Trident missile.108 If the Navy had continued to fund this missile, it might have provided a near-term alternative to the CTM. Reports indicate that test launches could have started around 2012, and the missile might have become operational between 2015 and 2018. As was noted above, however, this missile is not included in recent Navy budgets.
U.S. bombers—B-52s, B-2s, and B-1s—have the range and payload needed to deliver weapons to targets across the globe. But they may not be suited to the PGS mission because they could take hours or days to reach targets in remote areas, and they would require tanker support to refuel during their missions. The long flight time could contribute to crew fatigue, and air defenses could deny the bombers access to some critical target areas. The long flight time could also provide adversaries with warning of the impending attack. Conventional cruise missiles delivered by B-52 bombers would allow the aircraft to stay out of the range of some air-defense systems, but they could still take too long to reach their targets to meet the objectives of the PGS mission. On the other hand, the long flight duration could give the United States time to review and resolve the situation without resorting to military attacks. Moreover, because accurate and timely intelligence reports are critical to the success of long-range strike missions, the United States could use the time during the bombers' flights to acquire and update information on the target of the attack.
At the present time, the Navy has the capability to attack targets at ranges of around 1,500 nautical miles with sea-based cruise missiles. These Tomahawk missiles have been employed often in the conflicts in the past 20 years, providing the United States with the ability to reach targets without risking aircraft or their crews. The Navy has modified four of its Trident ballistic missile submarines so that they can carry cruise missiles. These submarines are equipped to carry up to 7 Tomahawk missiles each in up to 22 (out of 24) of their Trident launch tubes, for a total of 154 cruise missiles per submarine. But these missiles may be limited in their ability to contribute to the PGS mission. With a maximum speed of about 550 miles per hour and a range of 1,500 nautical miles, they can take two to three hours to reach their targets. Moreover, their reach is limited, even if the ships or submarines carrying the missiles are deployed in the region of the conflict. Consequently, the Navy has also explored alternatives that would allow it to reach its potential targets more quickly.
Since the mid-1990s, the Navy has explored several options for the development and deployment of an attack missile that could travel at speeds of Mach 3 to Mach 5.109 These hypersonic missiles would allow the Navy to attack targets within 15 minutes from ships or submarines based within 500 to 600 nautical miles of their targets. Hence, they would provide the capability for prompt strikes within the theater of operations, but they would not have the range sought for the PGS mission. The United States would either need to keep its vessels on station near potential areas of conflict, which it already does in certain areas, or it would need days or weeks to move its ships or submarines into place.
The Air Force, in collaboration with DARPA, NASA, and the Navy, is developing scramjet—supersonic combustion ramjet—technologies that may contribute to the long-range strike mission in the future. In this type of vehicle, the engine gets the oxygen it needs for combustion from the atmosphere passing through the vehicle, instead of from a tank onboard. This eliminates the need for heavy reservoir oxygen tanks, and makes the vehicle far smaller, lighter, and faster than a conventional rocket. According to NASA, a scramjet could, theoretically, travel at 15 times the speed of sound.110 The scramjet would destroy targets by crashing into them at hypersonic speeds. However, the Air Force may also use the technology to create a payload delivery vehicle that might carry conventional munitions and be launched on a long-range missile.111
The Air Force has designed an experimental scramjet, the X-51 WaveRider, that it can release from an Air Force bomber. It conducted a flight test of this vehicle on May 26, 2010. In this test, the vehicle was released at an altitude of 50,000 feet, from under the wing of a B-52 bomber.112 An Army tactical missile solid rocket booster accelerated the X-51 to a speed of approximately Mach 4.8, the speed required for the engine to ignite. The Air Force had intended for the scramjet to fly 300 seconds and reach speeds of 4,500 miles per hour, or six times the speed of sound.113 However, the vehicle did not reach either of those thresholds before it began to slow down. Reports indicated that the engine was flying normally when the vehicle started having control problems and was eventually terminated.114
The Air Force conducted three additional tests of the X-51A WaveRider. In the 2011 test, a mechanical problem caused it to end its operations earlier than planned. In the 2012 test, the system lost control due to a "faulty control fin" seconds after it the rocket booster ignited. However, in a fourth and final test of the X-51A in May 2013, the WaveRider reached a speed of Mach 5.1 and an altitude of 80,000 feet during its 300-second test flight.
This technology remains in its early stages, and could not contribute to the PGS mission for several years. However, because these vehicles would not leave the atmosphere or fly on a ballistic missile trajectory, they may address the nuclear ambiguity issues raised by long-range ballistic missiles in the CPGS program.
The United States could also deploy intermediate or long-range, land-based ballistic missiles at bases outside the continental United States. For example, they might be deployed in Guam, Diego Garcia, or Alaska. This system could use a two-stage rocket motor, to distinguish them from current nuclear-armed ICBMs, and could also, like the SLIRBM, carry either a guided warheads the AWH hypersonic glider. In addition, because it would be launched from outside the continental United States, its trajectory would not resemble that of a land-based ICBM. Hence, some analysts argue that it would solve many of the questions about the potential for misunderstandings and misperceptions. If the missiles had a range of less than 5,500 kilometers, they would be inconsistent with the limits in the 1987 Intermediate-Range Nuclear Forces Treaty. However, the United States has recently charged that Russia is in violation of the INF Treaty, leading some to conclude that this agreement should no longer constrain U.S. plans for intermediate-range systems.115
In April 2010, the United States and Russia signed a new strategic arms reduction treaty, known as New START.116 During the negotiations on New START, Russia voiced concerns about U.S. plans to deploy conventional warheads on ballistic missiles that now carry nuclear warheads. As was noted above, Russia believes these weapons would undermine strategic stability and increase the risk of nuclear war. The Obama Administration responded to Russia's concerns by noting the United States does not plan to target its PGS systems against Russia and that the United States would not deploy enough of these weapons to threaten Russia's strategic deterrent. Nevertheless, the preamble to the new treaty states that the parties are "mindful of the impact of conventionally armed ICBMs and SLBMs on strategic stability." However, according to the Obama Administration, neither this statement nor any other provisions in the treaty will "in any way limit or constrain research, development, testing, and evaluation (RDT&E) of any strategic concepts or systems, including prompt global strike capabilities."117
During the negotiations on New START, Russia initially sought to ban the deployment of conventional warheads on strategic ballistic missiles. The United States rejected this proposal because it would have interfered with ongoing U.S. plans and programs for the CPGS mission. As Rose Gottemoeller, the Assistant Secretary of State for Arms Control, Verification and Compliance, noted when she testified before the Senate Foreign Relations Committee, "We were firm during the negotiations that the treaty must allow for strategic missiles [of] conventional configuration."118 At the same time, however, the United States agreed that ballistic missiles armed with conventional warheads that were otherwise consistent with the treaty's definition of strategic ballistic missiles would count against the treaty's limits on deployed delivery vehicles. The warheads deployed on these missiles would similarly count against the treaty's limits on deployed warheads.119
Hence, under New START, U.S. land-based ballistic missiles armed with conventional warheads would count under the limits in New START if, according to paragraph 6 of Part One of the Treaty Protocol, the missile "has a ballistic trajectory over most of its flight path" and a range greater than 5,500 kilometers. Submarine-launched ballistic missiles would meet this criteria if they traveled on a ballistic trajectory for most of their flight path and had a range greater than 600 kilometers. Administration officials have explained that the United States accepted this provision because it would be nearly impossible to distinguish between a missile armed with nuclear warheads and one armed with conventional warheads, and, therefore, extremely difficult to verify compliance with the treaty limits if the missiles with conventional warheads did not count.
Moreover, the Administration insisted that, although the United States might have to reduce its number of nuclear warheads if it deployed conventional warheads on ballistic missiles that met this definition, the treaty's limits were high enough to "accommodate the level of CPGS deployments that is foreseeable over the lifetime of the treaty." In response to a question posed by the Senate Foreign Relations Committee, Secretary of Defense Gates stated that
as envisaged by our military planners, the number of such conventionally armed delivery vehicles and the warheads they carry would be very small when measured against the overall levels of strategic delivery systems and strategic warheads. Should we decide to deploy them, counting this small number of conventional strategic systems and their warheads toward the treaty limits will not prevent the United States from maintaining a robust nuclear deterrent.120
According to Administration officials, the New START Treaty, would, therefore, count the warheads deployed on CPGS systems, like the Navy's conventional Trident modification, that delivered reentry vehicles along a ballistic missile trajectory. It would not, however, capture warheads deployed on boost-glide systems, like the Air Force's conventional strike missile, that launched along a depressed trajectory and used a hypersonic glide vehicle to deliver weapons to targets. In testimony before the Senate Foreign Relations Committee, Principal Deputy Under Secretary of Defense for Policy James Miller stated that because boost-glide systems fly on a non-ballistic trajectory, "we are confident that such non-nuclear systems," which do not otherwise meet the definitions for the New START Treaty, "would not be accountable as new kinds of strategic offensive arms for the purposes of the treaty."121
Under the definitions in New START, these types of systems would qualify as new kinds of strategic offensive arms. Article V of the treaty indicates that, "when a Party believes that a new kind of strategic offensive arm is emerging, that Party shall have the right to raise the question of such a strategic offensive arm for consideration in the Bilateral Consultative Commission." As a result, Russia would have the opportunity to question the United States on whether the boost-glide systems should count under the treaty. But the United States would not have to delay the development, testing, and deployment of these systems while the discussions proceeded and it would not have to defer their deployment if Russia did not agree with the U.S. conclusion that these systems did not count under New START. In the article-by-article analysis submitted with the New START Treaty, the State Department indicated that "the deploying Party would be obligated to attempt to resolve the issue within the framework of the BCC [emphasis added]." But, according to the State Department, "there is no requirement in the treaty for the deploying Party to delay deployment of the new system pending such resolution."122
Section 1687 of the Defense Authorization Bill for Fiscal Year 2017 (P.L. 114-328) designates the Director of the Missile Defense Agency as DOD's executive agent for the development of a U.S. capability "to counter hypersonic boost-glide vehicle capabilities and conventional prompt strike capabilities that may be employed against" the United States, its allies, and its forces overseas. It mandates that the director develop "architectures for a hypersonic defense capability" and develop a program of record for this capability by September 30, 2017.
This provision reflects growing concerns in Congress and among some in the defense community about the efforts by potential U.S. adversaries, including Russia and China, to develop hypersonic boost-glide systems and, in some cases, hypersonic cruise missiles.123 The Strategic Forces Subcommittee of the House Armed Committee addressed these programs in a hearing in late 2015. Further, a study published by the National Academy of Sciences in late 2016 highlighted the complexities that such programs create for U.S. defensive programs and the "gaps and seams" that exist in U.S. efforts to address the threat. The summary to the study stated that high-speed maneuvering weapons, such as hypersonic cruise missiles or boost-glide vehicles, "can combine speed and maneuverability between the air and space regimes to produce significant new offensive capability that could pose a complex defensive challenge."124
The Bush Administration and the Obama Administration both supported the deployment of systems that employ long-range booster rockets and hypersonic payload delivery systems to fulfill the requirements of the prompt global strike mission. Both Administrations have argued that these systems can provide the United States with the ability to attack anywhere in the world on short notice, in support of regional or national security goals. They have both noted that, by strengthening the U.S. ability to attack at long ranges with conventional weapons, these systems could help reduce the number of circumstances when the United States might have to consider using nuclear weapons to defend its interests.
Critics, however, have argued that these weapons might provide the United States with more capability than it needs under most circumstances, while, at the same time, raising the possibility that their use might be misinterpreted—either as the launch of nuclear weapons or as the use of conventional weapons against nuclear targets. Moreover, as would be true for any weapon seeking to achieve this mission, the ability to attack targets across the globe on short notice depends on the U.S. ability to acquire precise information about the locations of potential targets and to translate that information into useful targeting data. If it takes longer for the United States to acquire and use that information than it would take for it to launch and deliver a ballistic missile, or, as has often been the case, if such precise information is unavailable, then the United States may not be able to benefit from the unique characteristics of long-range ballistic missiles. Bombers would take longer to reach their targets, but this added time might provide the United States with the opportunity to acquire the needed intelligence. A 2008 report by the Government Accountability Office (GAO) identified this particular problem, noting that many of the ongoing studies into global strike and prompt global strike have not addressed the need for critical enabling capabilities along with the weapons systems that would be used in the attacks.125
In addition, long-range ballistic missiles using boost-glide technologies would have an advantage over sea-based systems if the United States did not have naval forces near the conflict region, or did not have time to move these forces to the area, or if the target area were out of range for the sea-based systems. But the U.S. Navy deploys its force around the world and maintains capabilities near likely areas of conflict. A few targets may be out of range for these weapons, but bombers armed with cruise missiles might be able to reach them. Land-based long-range ballistic missiles would only be needed in the rare circumstance where the United States had no warning, needed a prompt attack, and had to reach too far inland for sea-based systems. But even in these circumstances, the benefits of the use of long-range ballistic missiles might not outweigh the risks.
During the Cold War, most analysts recognized that long-range land-based ballistic missiles could prove destabilizing in a crisis, when nations might have incomplete information about the nature of an attack and too little time to gather more information and plan an appropriate response. Faced with these circumstances, a nation who was not an intended target, such as Russia, might choose to respond quickly, rather than to wait for more information. The same could be true for the adversaries who are the intended targets of U.S. conventional prompt strike weapons. If the United States hoped to destroy a nation's military forces or weapons of mass destruction at the start of a conflict, before they could be used to degrade U.S. capabilities or attack U.S. forces, the other nation might choose to use these weapons even more quickly during a crisis, before it lost them to the U.S. attack.126
Some have argued that the possible crisis instabilities associated with long-range ballistic missiles should not eliminate them from consideration for the conventional prompt strike mission because the United States can work with Russia, China, and other nations to reduce the risks; also because no other weapons, at least in the short term, provide the United States with the ability to attack promptly anywhere on the globe at the start of an unexpected conflict. Yet the question of whether the United States should accept the risks associated with the potential for misunderstandings and crisis instabilities can be viewed with a broader perspective. How likely is the United States to face the need to attack quickly at great distances at the start of an unexpected conflict? How much would the United States lose if it had to wait a few hours or days to move its forces into the region (or to await the intelligence reports and precise targeting data needed for an attack)?
If the risks of waiting for bombers or sea-based weapons to arrive in the theater are high, then long-range ballistic missiles may be the preferred response, even with the risk that other nations might misunderstand U.S. intentions. On the other hand, if the risks of waiting for other forces to arrive in theater are deemed to be manageable, and the risks of potential misunderstandings and crisis instabilities associated with the launch of long-range ballistic missiles are thought to be high, then the United States can consider a broader range of alternative weapons systems to meet the needs of the PGS mission.
Author Contact Information
Melisa Woolfolk contributed diligent research and valued assistance in the preparation of this report.
U.S. Congress, Senate Committee on Armed Services, Hearing on the Nuclear Posture Review, Statement of the Honorable Douglas J. Feith, Under Secretary of Defense for Policy, February 14, 2002, p. 4.
U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34, http://www.defense.gov/npr/docs/2010%20Nuclear%20Posture%20Review%20Report.pdf.
See, for example, Watts, Barry D., Long-Range Strike: Imperatives, Urgency, and Options. Center for Strategic and Budgetary Assessments. April 2005.
U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, September 29, 2001, p. 43, http://www.comw.org/qdr/qdr2001.pdf.
U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, February 6, 2006, pp. 49-50, http://www.globalsecurity.org/military/library/policy/dod/qdr-2006-report.pdf.
U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, February 2010, pp. 32-33, http://www.defense.gov/qdr/images/QDR_as_of_12Feb10_1000.pdf.
This document was written by Air Force Space Command, coordinated with officials in the Joint Staff and the Office of the Secretary of Defense, and validated by the Joint Requirements Oversight Council (JROC). See, General John Jumper, U.S. Air Force, Final Mission Need Statement. "Prompt Global Strike," May 2, 2003.
Statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee, March 13, 2003.
U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, Testimony of Admiral James E. Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005.
Grossman, Elaine, M., "Hayden: 'Prompt Global Strike' Raises Bar for Intel Community." Inside The Air Force. June 22, 2007.
U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34, http://www.defense.gov/npr/docs/2010%20Nuclear%20Posture%20Review%20Report.pdf.
U.S. Department of Defense, "DOD Announces Merger of U.S. Space and Strategic Commands," June 26, 2002.
According to Admiral James O. Ellis, the Commander of STRATCOM, these missions included global strike planning and execution; information operations; global missile defense integrations; and oversight of command, control, communications, computers, intelligence, surveillance, and reconnaissance (C4ISR) in support of strategic and global operations. See Statement of Admiral James O. Ellis, Commander United States Strategic Command, before the House Armed Services Committee, March 13, 2003, p. 4.
A description of some of these scenarios can be found in the National Academies Study on Prompt Global Strike. See Committee on Conventional Prompt Global Strike Capability, National Research Council of the National Academies, U.S. Conventional Prompt Global Strike: Issues for 2008 and Beyond, Washington, DC, 2008, pp. 31-33.
U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology and Logistics, Time Critical Conventional Strike from Strategic Standoff, Report of the Defense Science Board Task Force, Washington, DC, March 2009, p. 2, http://www.acq.osd.mil/dsb/reports/ADA498403.pdf.
For a description of a range of possible scenarios, and the different requirements for prompt response, see James M. Acton, Silver Bullet? Asking the Right Questions About Prompt Global Strike (Washington, DC: Carnegie Endowment for International Peace, 2013), pp. 9-29.
In his testimony in 2003, Admiral Ellis specifically mentioned two systems that could contribute to this mission, Trident submarines reconfigured to carry Tomahawk cruise missiles with conventional warheads and the proposed Common Aero Vehicle, which could be used to deploy conventional munitions on long-range ballistic missiles. See the statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee, March 13, 2003. In the longer term, the Air Force and Navy are both exploring the use of ramjets, or scramjets, for long-range attack term. These hypersonic aircraft, which could fly at speeds of Mach 2-Mach 5, are still in the early stages of development. They are envisioned to launch from air bases, like aircraft, but to travel at speeds that far exceed those of U.S. aircraft and may approach the speeds of missiles. See, for example, Pincus, Walter, "Pentagon Has Far-reaching Defense Spacecraft in Works," Washington Post, March 16, 2005. p. 3.
See, for example, U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics, Report of the Defense Science Board Task Force on Future Strategic Strike Forces. February 2004. See, also, Eric A. Miller and Willis A. Stanley, The Future of Ballistic Missiles. National Institute for Public Policy, October 2003.
When the Cold War ended in the early 1990s these missiles carried more than 8,000 nuclear warheads. The United States has reduced its strategic forces, and currently has 2,000 warheads deployed on around 786 ICBMs and SLBMs. U.S. Department of State, The Legacy of START and Related U.S. Policies, Washington, DC, July 16, 2009, http://www.state.gov/t/vci/rls/126119.htm. See also, U.S. Department of State, START Aggregate Numbers of Strategic Offensive Arms, Washington, DC, July 1, 2009. http://www.state.gov/t/vci/rls/130149.htm.
U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics, Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1.
U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, Testimony of Admiral James E. Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005.
Grossman, Elaine M., "U.S. General: Precise Long-Range Missiles may Enable Big Nuclear Cuts," Inside the Pentagon, April 28, 2005.
Carlo Munoz, "Chilton: Conventional PGS Cannot Replace Nuclear Deterrent Role," Inside the Air Force, January 22, 2010.
U.S. Congress, House Armed Services, Strategic Forces, United States Strategic Posture and the Fiscal Year 2009 Budget Request for Strategic Programs, Hearing, 110th Cong., 2nd sess., March 27, 2008.
Elaine M. Grossman, "Conventional Arms No Substitute for Nuclear: Strategic Command Official," February 29, 2012.
Grossman, Elaine M. "Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs," Inside the Pentagon, June 27, 2002, p. 1.
Norris, Robert S. and Hans M. Kristensen. "U.S. Nuclear Forces 2005," Bulletin of the Atomic Scientists, January/February 2005, pp. 73-75.
According to the Defense Science Board Task Force on Future Strategic Strike Forces, the IMU would guide the missile in its early phases, but the reentry body would receive a GPS update during its exoatmospheric flight; it would then use the IMU and control flaps to steer the warhead with GPS-like accuracy during atmospheric reentry. See U.S. Department of Defense. Report of the Defense Science Board Task Force on Future Strategic Strike Forces. February 2004. pp. 5-7.
Grossman, Elaine M., "Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs," Inside the Pentagon, June 27, 2002. p. 1. See also, Robert S. Norris and Hans M. Kristensen, "U.S. Nuclear Forces 2005," Bulletin of the Atomic Scientists, January/February 2005, pp. 73-75.
Krivich, David, Director, SMP Advanced Programs and Business Development, Lockheed Martin Space Systems Company, Update on Precision Conventional Ballistic Missile Global Strike Capabilities, Briefing to the Defense Science Board Task Force on Nuclear Capabilities, July 22, 2005.
Department of the Navy, Fiscal Year 2008/2009 Budget Estimates, Justification of Estimates, February 2007, Research, Development, Test, and Evaluation, Navy Budget Activity 4.
Elaine M. Grossman, "Controversial Missile Idea Lingers," Global Security Newswire, March 20, 2008.
Elaine M. Grossman, "U.S. Navy Plans August Test for Conventional Trident-Related Technology," Global Security Newswire, May 21, 2009.
U.S. Department of Defense, Quadrennial Defense Review Report, February 6, 2006, p. 50.
Grossman, Elaine, "Pentagon Wants Early Start on Conventional Missiles for Subs." InsideDefense.Com, January 20, 2006. See also, Grossman, "Facing Doubts, Pentagon Readies Pitch for New Sub-launched Missile." Inside the Pentagon. March 9, 2006.
Norris, Robert S. and Hans M. Kristensen, "U.S. Nuclear Forces 2005," Bulletin of the Atomic Scientists, January/February 2005, pp. 73-75.
A Trident II (D-5) missile can deliver its warheads over a range of 4,000 miles.
Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004, pp. 5-12.
Koch, Andrew. "U.S. Considers Major Changes to Strategic Weapons," Jane's Defence Weekly, September 27, 2003.
Grossman, Elaine, M., "Midrange Missile May be Backup to Modified Trident," Global Security Newswire, September 21, 2007.
U.S. Department of Defense, Defense Budget Priorities and Choices, Washington, DC, January 2012, p. 5, http://www.defense.gov/news/Defense_Budget_Priorities.pdf.
Christopher P. Caves, "Subs May Serve Attack, Guided Missile Functions," Navy Times, October 15, 2011, http://www.navytimes.com/news/2011/10/navy-dual-use-submarines-attack-guided-missile-101511w/
U.S. Department of Defense, Major Budget Decisions Briefing From the Pentagon, Washington, DC, January 26, 2012, http://www.defense.gov/transcripts/transcript.aspx?transcriptid=4962.
DARPA, "FALCON (Force Application and Launch from CONUS Technology Demonstration Program," Fact Sheet, November 2003. See, also, Pincus, Walter, "Pentagon has Far-Reaching Defense Spacecraft in the works. Bush Administration Looking to Space to Fight Threats," Washington Post, March 16, 2005, p. 3.
Report to Congress on the "Concept of Operations" for the Common Aero Vehicle, Submitted in response to Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force, February 24, 2004. p. 2.
This implies that the U.S. command and control system would have the capability to identify potential targets, plan the mission, and prepare to launch the CAV within this time frame. These capabilities would be needed for the PGS mission, regardless of the munitions package on the ballistic missile.
Air Force Space Command, Common Aero Vehicle White Paper.
U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, Technology, and Logistics, Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1.
Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-3.
Eric Schmitt, "U.S. Considers Conventional Warheads on Nuclear Missiles," New York Times, February 24, 2003.
In 2006, the Bush Administration redesignated the CAV as the hypersonic technology vehicle, in response to the restrictions in the FY2005 Defense Appropriations Act.
Major Jason E. Seyer, USAF, "Adding the Conventional Strike Missile to the U.S.'s Deterrence Toolkit," High Frontier, February 2009, p. 32.
Michael Sirak, "Air Force Envisions Mid-Term, Prompt Global Strike Missile," Defense Daily, July 7, 2006.
Carlos Munez, "Services Collaborate on Long-Term Prompt Global Strike Study." Inside the Navy, September 10, 2007.
Emelie Rutherford, "AoA for Prompt Global Strike to go to JROC this Summer, Chilton Says," Defense Daily, March 5, 2008.
FY 2011 RDT&E Budget Item Justification, PE 0604165D8Z.
Elaine M. Grossman. "'Conventional Strike Missile' Proposed as Midterm Global Option," Inside Defense, April 6, 2006.
Elaine M. Grossman, "Chilton Shifts Prompt Strike Priority to the Air Force," Global Security Newswire, September 3, 2008.
U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research Development, Test and Evaluation. Defense Wide, Washington, DC, February 2010, p. 257, http://comptroller.defense.gov/defbudget/fy2011/budget_justification/pdfs/03_RDT_and_E/OSD%20RDTE_PB_2011_Volume%203B.pdf.
Major Jason E. Seyer, "Adding the Conventional Strike Missile to the US's Deterrence Toolkit," High Frontier, February 2009.
Major Jason E. Seyer, "Adding the Conventional Strike Missile to the US's Deterrence Toolkit," High Frontier, February 2009.
Grossman, Elaine M. "U.S. Military Eyes Fielding "Prompt Global Strike" Weapon by 2015," Global Security Newswire, July 1, 2009.
According to DOD, "the Army Hypersonic Glide Body (HGB) design provides an alternative risk reduction path within the Air Force CSM concept." See U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research Development, Test and Evaluation. Defense Wide, Washington, DC, February 2010, p. 257, http://comptroller.defense.gov/defbudget/fy2011/budget_justification/pdfs/03_RDT_and_E/OSD%20RDTE_PB_2011_Volume%203B.pdf.
Elaine M. Grossman, "U.S. Military Eyes Fielding 'Prompt Global Strike' Weapon by 2015," Global Security Newswire, July 1, 2009.
Elaine M. Grossman, "Cost to Test Global-Strike Missile could Reach $500 Million," Global Security Newswire, March 15, 2010.
Defense Advanced Research Projects Agency (DARPA_, Falcon Hypersonic Technology Vehicle 2 (HTV-2), Fact Sheet, Washington, DC, April 15, 2010.
U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research Development, Test and Evaluation. Defense Wide, Washington, DC, February 2010, p. 261, http://comptroller.defense.gov/defbudget/fy2011/budget_justification/pdfs/03_RDT_and_E/OSD%20RDTE_PB_2011_Volume%203B.pdf.
"Minotaur IV/HTV-2 Lifts Off," Targeted News Service, May 20, 2010.
Defense Advanced Projects Agency (DARPA), Falcon HTV-2 Launch Test Hypersonic Vehicle Flight Capabilities, Fact Sheet, Washington, DC, April 23, 2010.
Elaine M. Grossman, "Pentagon Nears Finding on Hypersonic Glider Test Failure," Global Security Newswire, August 19, 2010.
Elaine M. Grossman, "Pentagon Nears Finding on Hypersonic Glider Test Failure," Global Security Newswire, August 19, 2010.
Defense Advanced Research Projects Agency, DARPA Hypersonic Vehicle Splash Down Confirmed, Washington, DC, August 14, 2011, http://www.darpa.mil/NewsEvents/Releases/2011/2011/09/11_DARPA_HYPERSONIC_VEHICLE_SPLASH_DOWN_CONFIRMED.aspx.
Thom Shanker, "Brief Test of Military Aircraft Said To Yield Much Data," New York Times, August 12, 2011.
Elaine M. Grossman, "Army Eyes Advanced Hypersonic Weapon," Inside Defense, January 5, 2007.
Ann Roosevelt, "First Test Flight Successful for Advanced Hypersonic Weapon Vehicle," Defense Daily, November 18, 2011, p. 6.
Colin Clark, "Hypersonic Weapons Face Major Milestone in August Test," Breaking Defense, March 18, 2014.
Bill Gertz, "Army Hypersonic Missile Fails in Second Test," Washington Free Beacon, August 25, 2014.
Andrea Shalal and David Alexander, "Experimental U.S. Hypersonic Weapon Destroyed Seconds After Launch," Reuters, August 25, 2014.
Jason Sherman, "DOD Plans FY-17 'Flight Experiment' Of Hypersonic Weapon," Inside Defense, February 5, 2015.
Craig Hooper, "New Navy Missile Could Hit Global Targets," Military.com, July 8, 2010.
U.S. Congress, House, Making Appropriations for the Department of Defense for the Fiscal Year Ending September 30, 2005, and For Other Purposes, Conference Report to Accompany H.R. 4613, H.Rept. 108-622, p. 240.
Department of Defense Budget Appeal, FY2008 Defense Appropriations Bill, October 15, 2007.
Elaine M. Grossman, "Strategic Arms Funds Tilt Conventional in 2009," Global Security Newswire, November 7, 2008.
U.S. Congress, Senate Committee on Appropriations, Subcommittee on Defense, Defense Department Appropriations Bill, 2011, Report, 111th Cong., 2nd sess., September 15, 2010, S.Rept. 111-295 (Washington: GPO, 2010), p. 177.
U.S. Congress, House Committee on Armed Services, National Defense Authorization Act for Fiscal Year 2012, 112th Cong., 1st sess., May 17, 2011, H.Rept. 112-78. p. 69.
U.S. Department of Defense, Fiscal Year (FY) 2014 President's Budget Submission, Research, Development, Test & Evaluation, Defense-Wide, Washington, DC, April 2013, pp. 3-581, http://comptroller.defense.gov/defbudget/fy2014/budget_justification/pdfs/03_RDT_and_E/Office_of_the_Secretary_of_Defense_PB_2014.pdf.
Ibid., pp. 3-582.
U.S. Department of Defense, Defense Budget Priorities and Choices, Washington, DC, January 2012, p. 5, http://www.defense.gov/news/Defense_Budget_Priorities.pdf.
U.S. Department of Defense, Fiscal Year (FY) 2014 President's Budget Submission, Research, Development, Test & Evaluation, Defense-Wide, Washington, DC, April 2013, pp. 3-590.
Elaine M. Grossman, "Russian Experts Question Role of Conventional "Prompt Global Strike" Weapons," Global Security Newswire, April 7, 2009.
For a detailed discussion of stability concerns associated with CPGS, and a review of Russian and Chinese objections to the program, see James M. Acton, Silver Bullet? Asking the Right Questions About Conventional Prompt Global Strike (Washington, DC: Carneige Endowment for International Peace, 2013), pp. 111-126.
Barry Watts, an analyst expert in this subject has stated that, "for those rare occasions when it really is imperative to be able to strike anywhere on the globe from the United States as quickly as possible, a long-range ballistic missile solution is the most sensible near-term option in light of cost and technological risk." But he has also asserted that it may be "far more important to be able to dwell or loiter to await information and take advantage of opportunities" to attack hidden or mobile targets during a conflict. Watts, Barry D. Long-Range Strike: Imperatives, Urgency and Options, Center for Strategic and Budgetary Assessments, April 2005.
For a description of ongoing problems with Russia's early warning system for ballistic missile attack, see Mosher, David E. et al., Beyond the Nuclear Shadow: A Phased Approach for Improving Nuclear Safety and U.S.-Russian Relations, RAND Corporation, 2003. p. 5.
National Research Council of the National Academies, U.S. Conventional Prompt Global Strike: Issues for 2008 and Beyond, Washington, DC, August 2008, p. 72.
Ibid., p. 72.
Ibid., p. 75.
Report to Congress on the "Concept of Operations" for the Common Aero Vehicle. Submitted in response to Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force. February 24, 2004. p. 4.
The United States uses a similar formula with its B-1 bombers. Although they were originally equipped to carry nuclear weapons, they have been deployed at bases that do not house nuclear weapons and redesignated as conventional bombers. Hence, their weapons delivery status is determined by basing and declaration, rather than by their original nuclear capabilities.
Air Force Space Command, Common Aero Vehicle White Paper, p. 8.
Ibid., p. 7.
Report to Congress on the "Concept of Operations" for the Common Aero Vehicle, Submitted in response to Congressional Reporting Requirements, by Peter B. Teets, Under Secretary of the Air Force, February 24, 2004, p. 4.
Air Force Space Command, Common Aero Vehicle White Paper, p. 11.
DARPA, "FALCON (Force Application and Launch from CONUS Technology Demonstration Program," Fact Sheet, November 2003.
Grossman, Elaine M. "Navy Eyes New Weapon for Global Strike, Missile Defense," Global Security Newswire, July 17, 2008.
Dan Taylor, "Official: No Conventional Trident, But a Smaller Missile is Possible," Inside Defense, July 21, 2008.
For a summary of these programs see Statement of [author name scrubbed], Specialist in National Defense, Congressional Research Service, before the House Armed Services Committee, Subcommittee on Projection Forces, Hearing on Long-Range Strike Options, March 3, 2004. pp. 10-11.
Boeing, "Boeing X-51A WaveRider Breaks Record in 1st Flight," Information Sheet, http://www.boeing.mediaroom.com, May 26, 2010.
Boeing, "Boeing, Air Force Research Lab, Pratt & Whitney Rocketdyne to Conduct X-51A WaveRider Flight Test on May 25," Information Sheet, http://www.boeing.mediaroom.com, May 20, 2010.
"Early Waverider Findings," Aviation Week and Space Technology, June 7, 2010.
For information on the current dispute over the INF Treaty, see CRS Report R43832, Russian Compliance with the Intermediate Range Nuclear Forces (INF) Treaty: Background and Issues for Congress, by [author name scrubbed].
For details on the limits and restrictions in this Treaty see CRS Report R41219, The New START Treaty: Central Limits and Key Provisions, by [author name scrubbed].
U.S. Congress, Senate Committee on Foreign Relations, Treaty With Russia on Measures for Further Reduction and Limitation of Strategic Offensive Arms (the New START Treaty), 111th Cong., 2nd sess., October 1, 2010, Exec Rpt. 111-6, p. 56. See, also, U.S. State Department, Bureau of Verification, Compliance, and Implementation, Conventional Prompt Global Strike, Fact Sheet, Washington, DC, April 8, 2010, http://www.state.gov/t/vci/rls/139913.htm.
U.S. Congress, Senate Committee on Foreign Relations, Treaty With Russia on Measures for Further Reduction and Limitation of Strategic Offensive Arms (the New START Treaty), 111th Cong., 2nd sess., October 1, 2010, Exec Rpt. 111-6, pp. 51-52.
Ibid., p. 52.
Ibid., p. 54.
Ibid., p. 55.
U.S. Department of State, Article-by-Article Analysis of the New START Treaty Documents, Washington, DC, May 5, 2010, http://www.state.gov/t/avc/trty/141829.htm#text.
Bill Gertz, "Air Force: Hypersonic Missiles from China, Russia Pose Growing Danger to U.S.," Washington Free Beacon, November 30, 2016. See, also James Acton, "The Arms Race Goes Hypersonic," Foreign Policy, January 30, 2014.
National Academy of Sciences, High-Speed Maneuvering Weapons: A Threat to America's Global Vigilance, Reach, and Power, Unclassified Summary, Washington, D.C., November 2016, p. 4, https://www.nap.edu/read/23667/chapter/1#ii.
U.S. Government Accountability Office, Military Transformation, "DOD Needs to Strengthen Implementation of its Global Strike Concept and Provide a Comprehensive Investment Approach for acquiring Needed Capabilities." GAO-08-325. April 2008. p. 5.
James M. Acton, Silver Bullet? Asking the Right Questions About Prompt Global Strike (Washington, DC: Carnegie Endowment for International Peace, 2013), pp. 120-129.