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Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues

CRS Report for Congress
Prepared for Members and Committees of Congress
Conventional Prompt Global Strike and
Long-Range Ballistic Missiles: Background
and Issues
Amy F. Woolf
Specialist in Nuclear Weapons Policy
January 10, 2013
Congressional Research Service
7-5700
www.crs.gov
R41464
Conventional Prompt Global Strike and Long-Range Ballistic Missiles
Congressional Research Service
Summary
Prompt global strike (PGS) would allow the United States to strike targets anywhere on Earth
with conventional weapons 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.
Many analysts believe that the United States should use long-range ballistic missiles armed with
conventional warheads for the PGS mission. These weapons would not substitute for nuclear
weapons in the U.S. war plan but would, instead, provide a “niche” capability, with a small
number of weapons directed against select, critical targets, which might expand the range of U.S.
conventional options. 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. 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 longrange
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 DARPA are
developing a hypersonic glide delivery vehicle that could deploy on a modified Peacekeeper landbased
ballistic missile—a system known as the Conventional Strike Missile (CSM). In FY2008,
Congress created a single, combined fund for the conventional prompt global strike (CPGS)
mission. This fund is supporting research and development into the Air Force CSM and two
possible hypersonic glide vehicles. Congress appropriated $174.8 million for CPGS capability
development in FY2012; DOD has requested $110.4 million in FY2013.
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.
Although the Air Force Conventional Strike Missile is a key contender for the CPGS mission, the
Air Force may not be able to deploy this system until later in this decade, as the hypersonic glide
vehicle has not yet had a successful test flight. Hence, Congress may review other weapons
options for the PGS mission. These include not only ballistic missiles and boost-glide systems,
but also bombers, cruise missiles, and possibly scramjets or other advanced technologies.
Finally, Congress is likely to question how the New START Treaty, signed by the United States
and Russia in April 2010, would affect U.S. plans for the CPGS mission. Warheads deployed on
boost-glide systems would not be affected by the 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.
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Contents
Introduction ...................................................................................................................................... 1
Background ...................................................................................................................................... 2
The Prompt Global Strike Mission (PGS) ................................................................................. 2
Rationale for the PGS Mission ............................................................................................ 2
PGS and the U.S. Strategic Command ................................................................................ 4
Potential Targets for the PGS Mission ................................................................................ 5
Conventional Ballistic Missiles and the PGS Mission .............................................................. 6
Plans and Programs .......................................................................................................................... 8
Navy Programs .......................................................................................................................... 8
Reentry Vehicle Research .................................................................................................... 8
Conventional Trident Modification ................................................................................... 10
Submarine-Launched Intermediate-Range Global Strike ................................................. 11
Air Force Programs ................................................................................................................. 13
The FALCON Study .......................................................................................................... 13
Reentry Vehicle Research and Warhead Options .............................................................. 14
Missile Options ................................................................................................................. 15
Defense-Wide Conventional Prompt Global Strike ................................................................. 16
The Conventional Strike Missile ....................................................................................... 16
Hypersonic Test Vehicle (HTV-2) ..................................................................................... 17
Army Advanced Hypersonic Weapon ............................................................................... 19
ArcLight ............................................................................................................................ 19
Legislative Activity ................................................................................................................. 20
FY2003 and FY2004 ......................................................................................................... 20
FY2005 .............................................................................................................................. 21
FY2006 and FY2007 ......................................................................................................... 21
FY2008 .............................................................................................................................. 22
FY2009 .............................................................................................................................. 24
FY2010 .............................................................................................................................. 25
FY2011 .............................................................................................................................. 25
FY2012 .............................................................................................................................. 26
FY2013 .............................................................................................................................. 26
Issues for Congress ........................................................................................................................ 27
Assessing the Rationale for CPGS .......................................................................................... 27
Reducing Reliance on Nuclear Weapons .......................................................................... 27
PGS ................................................................................................................................... 28
The Potential for Misunderstanding a CPGS Missile Launch ................................................. 29
Mitigating the Risks .......................................................................................................... 30
Remaining Concerns ......................................................................................................... 32
Reviewing the Alternatives ...................................................................................................... 32
Land-Based Ballistic Missiles ........................................................................................... 32
Submarine-Launched Ballistic Missiles ............................................................................ 33
Submarine-Launched Intermediate-Range Ballistic Missiles ........................................... 34
Long-Range Bombers ....................................................................................................... 34
Tomahawk Cruise Missiles ............................................................................................... 34
Hypersonic Cruise Missiles ............................................................................................... 35
Scramjet Technologies ...................................................................................................... 35
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Forward-Based Global Strike (FBGS) .............................................................................. 36
Arms Control Issues ................................................................................................................ 36
Weighing the Benefits and Risks ............................................................................................. 38
Contacts
Author Contact Information........................................................................................................... 39
Acknowledgments ......................................................................................................................... 39
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Introduction
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. 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 in hour, with conventional warheads. The Obama Administration, in
the 2010 Nuclear Posture Review, 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.
Many analysts believe that long-range ballistic missiles armed with conventional warheads would
be an ideal weapon for this mission. They note 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. Some analysts, however, 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
1 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.
2 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.
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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.
Background
The Prompt Global Strike Mission (PGS)
Rationale for the PGS Mission
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. 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
3 See, for example, Watts, Barry D., Long-Range Strike: Imperatives, Urgency, and Options. Center for Strategic and
Budgetary Assessments. April 2005.
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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 re-locatable 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 forwarddeployed
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 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 U.S. Strategic Command (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,
4 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, September 29, 2001, p. 43.
http://www.comw.org/qdr/qdr2001.pdf.
5 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.
6 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.
7 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.
8 Statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee,
March 13, 2003.
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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
PGS and the U.S. Strategic Command
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
9 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.
10 Grossman, Elaine, M., “Hayden: ‘Prompt Global Strike’ Raises Bar for Intel Community.” Inside The Air Force.
June 22, 2007.
11 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.
12 U.S. Department of Defense. “DOD Announces Merger of U.S. Space and Strategic Commands,” June 26, 2002.
13 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.
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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
Potential Targets for the PGS Mission
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 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:
• A near-peer competitor had used its emerging counter-space capability to destroy
a U.S. satellite.
• The United States wanted to destroy a package of special nuclear materials that a
terrorist organization had shipped to a neutral country.
• A small package of weapons of mass destruction was located temporarily in a
rural area of a neutral country.
• The leadership of a terrorist organization had gathered in a known location in a
neutral country.
• A rogue state armed with a nuclear weapon was threatening to use that weapon
against a U.S. ally.
14 http://www.stratcom.mil/factsheets/gs/.
15A 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.
16 U.S. Department of Defense, Office of the Under Secretary of Defense for Acquistion, 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.
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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.
Conventional Ballistic Missiles and the PGS Mission
The Obama Administration noted, in the 2010 Nuclear Posture Review, 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 Quadrennial Defense Review
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.17 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 and officials believe that the United States should use long-range
ballistic missiles (ICBMs and SLBMs) for the prompt global strike mission.18 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.19 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 Nuclear Posture Review, 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.
17 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. The 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.
18 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.
19 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.
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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.”20 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”21 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 number of deployed strategic nuclear weapons.22
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 are exploring advanced guidance
and targeting technologies, such as the use of GPS guidance, that might provide their missiles
with these improvements in accuracy. This effort has been underway for more than two decades.
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.23
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
U.S. Strategic Command, 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
20U.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.
21 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.
22 Grossman, Elaine M., “U.S. General: Precise Long-Range Missiles may Enable Big Nuclear Cuts,” Inside the
Pentagon, April 28, 2005.
23 Ibid.
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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.24 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
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 selfdeterring
to address that threat.”25
Nevertheless, 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 Undersecretary 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.26 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.
Plans and Programs
Both the Navy and the Air Force have studied the possible deployment of conventional warheads
on their long-range ballistic missiles for more than a decade. 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.27 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.
Navy Programs
Reentry Vehicle Research
In FY2003, the Navy requested funding for research on a new type of reentry vehicle that could
significantly improve the accuracy of the Trident II (D-5) missiles. This program, known as the
24 Carlo Munoz, “Chilton: Conventional PGS Cannot Replace Nuclear Deterrent Role,” Inside the Air Force, January
22, 2010.
25 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.
26 Elaine M. Grossman, “Conventional Arms No Substitute for Nuclear: Strategic Command Official,” February 29,
2012.
27 Grossman, Elaine M. “Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs,” Inside the Pentagon,
June 27, 2002, p. 1.
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Enhanced Effectiveness (E2) Initiative, included an initial funding request of $30 million, a threeyear
study, and a full-scale flight test in early 2007.28 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.29 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.30
Lockheed Martin flew these reentry vehicles in test flights of Trident missiles.31 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 FY2009.32 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
28 Norris, Robert S. and Hans M. Kristensen. “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,
January/February 2005, pp. 73-75.
29 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.
30 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.
31 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.
32 Department of the Navy, Fiscal Year 2008/2009 Budget Estimates, Justification of Estimates, February 2007,
Research, Development, Test, and Evaluation, Navy Budget Activity 4.
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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 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 would have 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.
Nevertheless, DOD has allocated a portion of the combined funding for the PGS mission to this
program area in recent years. 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.”33 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.34 DOD has
indicated that during FY2012, it will 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 submarinelaunched
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.
Conventional Trident Modification
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,
33 Elaine M. Grossman, “Controversial Missile Idea Lingers,” Global Security Newswire, March 20, 2008.
34 Elaine M. Grossman, “U.S. Navy Plans August Test for Conventional Trident-Related Technology,” Global Security
Newswire, May 21, 2009.
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and only one or two of the submarines would likely be within range of the targets specified for
attack with conventional ballistic missiles.35
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 precisionguided
conventional warheads using long-range Trident” missiles within two years,36 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 FY2010.37 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.
Submarine-Launched Intermediate-Range Global Strike
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 2005.38
According to the Defense Science Board Task Force, this missile might deliver a 2,000-pound
payload over a 1,500-mile range,39 with an accuracy of less than 5 meters. This would allow the
missile to reach its target in less than 15 minutes.40 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.41 These missiles
35 Ibid.
36 U.S. Department of Defense, Quadrennial Defense Review Report, February 6, 2006, p. 50.
37 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.
38 Norris, Robert S. and Hans M. Kristensen, “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,
January/February 2005, pp. 73-75.
39 A Trident II (D-5) missile can deliver its warheads over a range of 4,000 miles.
40 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004, p. 5-12.
41 Koch, Andrew. “U.S. Considers Major Changes to Strategic Weapons,” Jane’s Defence Weekly, September 27, 2003.
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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 become evident that the missiles would be 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.42 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.”43 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.44
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
42 Grossman, Elaine, M., “Midrange Missile May be Backup to Modified Trident,” Global Security Newswire,
September 21, 2007.
43 U.S. Department of Defense, Defense Budget Priorities and Choices, Washiington, D.C., January 2012, p. 5,
http://www.defense.gov/news/Defense_Budget_Priorities.pdf.
44 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/
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adversary observing the launch and concluding, incorrectly, that the United States had launched
an attack with a nuclear-armed missile.45
Air Force Programs
The FALCON Study
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.46 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.47 These characteristics would provide it with the
capabilities needed to attack time-sensitive targets.48
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
45 U.S. Department of Defense, Major Budget Decisions Briefing From the Pentagon, Washington, D.C., January 26,
2012, http://www.defense.gov/transcripts/transcript.aspx?transcriptid=4962.
46 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.
47 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.
48 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.
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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.”49 The two potential bases included Vandenberg Air Force Base on the
West Coast and Cape Canaveral on the East Coast.
Although the FALCON study focused on the booster and delivery vehicle that the United States
would need to pursue the prompt global strike mission, analysts have 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.
Reentry Vehicle Research and Warhead Options
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.50 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.51 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.”52 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.53 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.
49 Air Force Space Command, Common Aero Vehicle White Paper.
50U.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.
51 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-3.
52 Eric Schmitt, “U.S. Considers Conventional Warheads on Nuclear Missiles,” New York Times, February 24, 2003.
53 In 2006, the Bush Administration redesignated the CAV as the Hypersonic Technology Vehicle, in response to the
restrictions in the FY2005 Defense Appropriations Act.
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The Air Force is considering two types of warheads for the CPGS mission.54 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 becomes 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.
Missile Options
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. It is currently developing a Minotaur IV missile, which would use three
stages from the Peacekeeper missile and a new fourth stage developed by Orbital Sciences
Corporation. The Minotaur IV missile is now expected to serve as the boost vehicle for the 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.55
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 “servicespecific”
platforms, and considering a range of alternative platforms, across service lines, for the
long-term PGS option.56 These include a long-range land-based option, a shorter-range forward
54 Major Jason E. Seyer, USAF, “Adding the Conventional Strike Missile to the U.S.’s Deterrence Toolkit,” High
Frontier, February 2009, p. 32.
55 Michael Sirak, “Air Force Envisions Mid-Term, Prompt Global Strike Missile,” Defense Daily, July 7, 2006.
56 Carlos Munez, “Services Collaborate on Long-Term Prompt Global Strike Study.” Inside the Navy, September 10,
2007.
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deployed land-based missile, a sea-based option, and an air-breathing option. The Air Force
completed this study in 2008.57
Defense-Wide Conventional Prompt Global Strike
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 Conventional Trident Modification
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.58 The key
programs that receive support from these funds are the Air Force CSM, the DARPA/Air Force
HTV-2 program, and the Army Advanced Hypersonic Weapon (AHW).
The Conventional Strike Missile
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,59 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-2008.60 According to DOD, the CSM is the “lead design to demonstrate a possible materiel
solution for the CPGS warfighting capability gap.”61
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.62 The CSM would not follow the standard ballistic trajectory of
nuclear-armed ballistic missiles. Its booster would launch with a lower-profile, or depressed,
57 Emelie Rutherford, “AoA for Prompt Global Strike to go to JROC this Summer, Chilton Says,” Defense Daily,
March 5, 2008.
58 FY 2011 RDT&E Budget Item Justification, PE 0604165D8Z.
59 Elaine M. Grossman. “‘Conventional Strike Missile’ Proposed as Midterm Global Option,” Inside Defense, April 6,
2006.
60 Elaine M. Grossman, “Chilton Shifts Prompt Strike Priority to the Air Force,” Global Security Newswire, September
3, 2008.
61 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.
62 Major Jason E. Seyer, “Adding the Conventional Strike Missile to the US’s Deterrence Toolkit,” High Frontier,
February 2009.
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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.63 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 current plans, the CSM would combine the Minotaur IV launch vehicle described
above with a hypersonic payload delivery vehicle (PDV).64 Under current plans the first PDV will
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.65 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 2015.66 However, according to DOD officials, the program does
not yet 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 2013, or later, depending on progress in the testing program.67
Hypersonic Test Vehicle (HTV-2)
DARPA has 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.68
DARPA plans to acquire and test two vehicles. The Air Force has also contracted with Lockheed
Martin to produce a third vehicle, which the Air Force will use as the payload delivery vehicle
(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 has requested an
63 Major Jason E. Seyer, “Adding the Conventional Strike Missile to the US’s Deterrence Toolkit,” High Frontier,
February 2009.
64 Grossman, Elaine M. “U.S. Military Eyes Fielding “Prompt Global Strike” Weapon by 2015,” Global Security
Newswire, July 1, 2009.
65 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.
66 Elaine M. Grossman, “U.S. Military Eyes Fielding ‘Prompt Global Strike’ Weapon by 2015,” Global Security
Newswire, July 1, 2009.
67 Elaine M. Grossman, “Cost to Test Global-Strike Missile could Reach $500 Million,” Global Security Newswire,
March 15, 2010.
68 Defense Advanced Research Projects Agency (DARPA_, Falcon Hypersonic Technology Vehicle 2 (HTV-2), Fact
Sheet, Washington, DC, April 15, 2010.
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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 will 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.69
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.70 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.71 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.72 DOD reviewed the results of the April 2010 test, in
an effort to determine what caused the vehicle to fail during its flight.73 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 perigree.”
This prompted the system to make a “controlled descent and splash down in the ocean.”74 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 has 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.75
DOD allocated $51.8 million to this program area in FY2012 and has requested an additional
$49.5 million for FY2013. According to DOD, in FY2011, it completed finalized the design
69 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.
70 “Minotaur IV/HTV-2 Lifts Off,” Targeted News Service, May 20, 2010.
71 Defense Advanced Projects Agency (DARPA), Falcon HTV-2 Launch Test Hypersonic Vehicle Flight Capabilities,
Fact Sheet, Washington, DC, April 23, 2010.
72 Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider Test Failure,” Global Security Newswire,
August 19, 2010.
73 Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider Test Failure,” Global Security Newswire,
August 19, 2010.
74 Defense Advanced Research Projects Agency, DARPA Hypersonic Vehicle Splash Down Confirmed, Washington,
D.C., August 14, 2011, http://www.darpa.mil/NewsEvents/Releases/2011/2011/09/
11_DARPA_HYPERSONIC_VEHICLE_SPLASH_DOWN_CONFIRMED.aspx.
75 Thom Shanker, “Brief Test of Military Aircraft Said To Yield Much Data,” New York Times, August 12, 2011.
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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.
Army Advanced Hypersonic Weapon
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, or advanced
hypersonic weapon in FY2006, and added $8.9 million in FY2007.76 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 has requested an additional $42 million for FY2013. DOD has
indicated that this program is 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.”
The Army conducted a successful flight test of the AHW on November 17, 2011.77 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.
ArcLight
DARPA also 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.”78 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.
76 Elaine M. Grossman, “Army Eyes Advanced Hypersonic Weapon,” Inside Defense, January 5, 2007.
77 Ann Roosevelt, “First Test Flight Successful for Advanced Hypersonic Weapon Vehicle,” Defense Daily, November
18, 2011, p. 6.
78 Craig Hooper, “New Navy Missile Could Hit Global Targets,” Military.com, July 8, 2010.
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However, it seems to have terminated the program and has not requested any additional funding
in FY2012.
Legislative Activity
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.
FY2003 and FY2004
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.”
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FY2005
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.79
FY2006 and FY2007
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 nearterm
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
79 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.
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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.”
FY2008
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
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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.80 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
80 Department of Defense Budget Appeal, FY2008 Defense Appropriations Bill, October 15, 2007.
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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).
FY2009
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 seabased
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 Re-entry 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 oneConventional
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fourth” of the funds provided, or $19 million, must be “available” for the Advanced Hypersonic
Weapon under development by the Army.81
FY2010
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.
FY2011
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 Alternative 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.82 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.
81 Elaine M. Grossman, “Strategic Arms Funds Tilt Conventional in 2009,” Global Security Newswire, November 7,
2008.
82 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.
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FY2012
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.”83 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 milllion 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.
FY2013
The Pentagon budget request for FY2013 includes $110.383 million for the CPGS program.
Within this total, DOD has 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
83 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.
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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.
Issues for Congress
Assessing the Rationale for CPGS
Reducing Reliance on Nuclear Weapons
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 nucleararmed
nations.
As a result, most of the supporters of the CPGS mission now refer 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 in rare circumstances. 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.
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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.84 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.
PGS
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
84 Elaine M. Grossman, “Russian Experts Question Role of Conventional “Prompt Global Strike” Weapons,” Global
Security Newswire, April 7, 2009.
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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, seabased
or air-launched cruise missiles may also be too slow too 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?85 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.
The Potential for Misunderstanding a CPGS Missile Launch
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.86 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
85 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.
86 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.
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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.”87 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.”88
Mitigating the Risks
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.89 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 has indicated 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,”90 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
87 National Research Council of the National Academies, U.S. Conventional Prompt Global Strike: Issues for 2008 and
Beyond, Washington, DC, August 2008, p. 72.
88 Ibid., p. 72.
89 Ibid., p. 75.
90 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.
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from nuclear ICBMs, even though it would not preclude the possible covert deployment of
nuclear warheads on the missiles.91 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.92
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.93 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.94 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 has 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.95 DOD has indicated that the same would be true of an 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.
91 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.
92 Air Force Space Command, Common Aero Vehicle White Paper, p. 8.
93 Ibid., p. 7.
94 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.
95 Air Force Space Command, Common Aero Vehicle White Paper, p. 11.
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Remaining Concerns
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.
Reviewing the Alternatives
As the preceding discussion indicates, the United States is currently exploring a number of
alternatives for weapons systems that could contribute to the PGS mission. The Air Force
Conventional Strike Missile, armed with a payload delivery vehicle derived from either the
DARPA/Air Force HTV-2 vehicle or the Army AHW vehicle, appears to be the main contender
for this mission at the present time. However, according to most analysts, the Air Force will not
be able to deploy this system until the latter part of this decade, as the hypersonic glide vehicle
has not yet had a successful test flight. As a result, while reviewing Administration requests for
funding for the PGS mission, Congress could consider a range of alternative weapons systems.
Land-Based Ballistic Missiles
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
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hostile countries and terrorist organizations.”96 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
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.
96 DARPA, “FALCON (Force Application and Launch from CONUS Technology Demonstration Program,” Fact
Sheet, November 2003.
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Submarine-Launched Intermediate-Range Ballistic Missiles
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.97 Further, the warhead under development for
this missile would be too tall to fit on a Trident missile.98 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.
Long-Range Bombers
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 time of flight 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.
Tomahawk Cruise Missiles
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
97 Grossman, Elaine M. “Navy Eyes New Weapon for Global Strike, Missile Defense,” Global Security Newswire, July
17, 2008.
98 Dan Taylor, “Official: No Conventional Trident, But a Smaller Missile is Possible,” Inside Defense, July 21, 2008.
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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.
Hypersonic Cruise Missiles
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 5.99 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.
Scramjet Technologies
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.100 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.101
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.102
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.103
However, the vehicle did not reach either of those thresholds before it began to slow down.
99 For a summary of these programs see Statement of Ronald O’Rourke, 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.
100 http://www.nasa.gov/missions/research/f_scramjets.html.
101 Boeing, “Boeing X-51A WaveRider Breaks Record in 1st Flight,” Information Sheet,
http://www.boeing.mediaroom.com, May 26, 2010.
102 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.
103 Ibid.
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Reports indicated that the engine was flying normally when the vehicle started having control
problems and was eventually terminated.104
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.
Forward-Based Global Strike (FBGS)
Analysts have also explored the option of deploying 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 would use a two-stage rocket motor, with a payload of up to 1,000
pounds, a flight time to target of less than 25 minutes, and an accuracy of less than 5 meters. It
could employ many of the same reentry vehicle and warhead options as the CTM and CSM
systems. Because it would rely on existing rocket technologies, it might be available for
deployment by 2012, in roughly the same time frame as the CSM system. However, 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 misunderstandings and misperceptions that plague the CTM and CSM systems.
Arms Control Issues
In April 2010, the United States and Russia signed a new strategic arms reduction treaty, known
as New START.105 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.”106
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
104 “Early Waverider Findings,” Aviation Week and Space Technology, June 7, 2010.
105 For details on the limits and restrictions in this Treaty see CRS Report R41219, The New START Treaty: Central
Limits and Key Provisions, by Amy F. Woolf.
106 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.
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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.”107 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.108
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.109
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.”110
107 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.
108 Ibid., p. 52.
109 Ibid., p. 54.
110 Ibid., p. 55.
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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 boostglide
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.”111
Weighing the Benefits and Risks
The Bush Administration and the Obama Administration have 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 as the launch of nuclear weapons. For example, 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.112
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
111 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.
112 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.
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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. ballistic missiles. 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 against U.S. troops, the other nation might choose to use these weapons
even more quickly during a crisis, before it lost them to the U.S. attack.
Some have argued that the possible crisis instabilities associated with long-range ballistic missiles
should not eliminate them from consideration for the PGS 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.

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