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

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/crs%3AR41464

## Record

- **Collection:** Congressional research report
- **Document type:** CRS Report
- **Published:** July 16, 2021
- **Citation:** R41464

## Text

Conventional Prompt Global Strike and
Long-Range Ballistic Missiles:
Background and Issues
Updated July 16, 2021

Congressional Research Service
https://crsreports.congress.gov
R41464

Conventional Prompt Global Strike and Long-Range Ballistic Missiles

Summary
Members of Congress and Pentagon officials have placed a growing emphasis on U.S. programs
to develop hypersonic weapons—those that can travel at speeds greater than Mach 5 and
maneuver to improve accuracy or evade defenses as they approach their targets. Initially, the
United States sought to develop systems with intermediate or long range, so that they could attack
targets around the world in under an hour. These types of prompt strike weapons might 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
this mission, but restricted funding for several years in the 2000s. Recently, efforts to develop a
long-range prompt strike capability, along with other efforts to develop extremely fast hypersonic
weapons, have garnered increased support.
Prompt strike weapons would not substitute for nuclear weapons, but would supplement U.S.
conventional capabilities. Officials have argued that the long-range systems would provide a
“niche” capability, with a small number of weapons directed against select, critical targets. Some
analysts, however, have raised concerns about the possibility that U.S. adversaries might
misinterpret the launch of a missile with conventional warheads and conclude that the missiles
carry nuclear weapons. The U.S. Department of Defense (DOD) is considering a number of
systems that might provide the United States with long-range strike capabilities.
The Air Force and Navy have both pursued programs that would lead to the deployment of
conventional warheads on their long-range ballistic missiles. During the 2000s, the Air Force and
the Defense Advanced Research Projects Agency (DARPA) sought to develop a hypersonic glide
delivery vehicle that could deploy on a modified Peacekeeper land-based ballistic missile, but test
failures led to the suspension of this program; research continues into a vehicle that might be
deployed on air-delivered or shorter-range systems. In the mid-2000s, the Navy sought to deploy
conventional warheads on a small number of Trident II submarine-launched ballistic missiles, but
Congress rejected the requested funding for this program. Since then, the Pentagon has continued
to develop a hypersonic glide vehicle, now known as the Common Hypersonic Glide Body, which
could be deployed on long-range missiles. This vehicle is likely to be deployed on intermediaterange missiles on Navy submarines, for what is now known as the Prompt Strike Mission.
Congress may review other weapons options for the deployment of hypersonic weapons,
including bombers, cruise missiles, and possibly scramjets or other advanced technologies.
The Pentagon’s FY2022 budget request continues to show significant increases in funding for the
Navy’s Conventional Prompt Strike (CPS) program. The Navy received $512 million for this
program in FY2020 and requested $1.1 billion for FY2021; Congress appropriated $766.6 million
for FY2021. The Navy has requested $1.4 billion for FY2022. This shows the growing priority
placed on the program in the Pentagon and the growing interest in Congress in moving the
program forward toward deployment.
When Congress reviews the budget requests for prompt strike and other hypersonic weapons
programs, 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. At the same time,
Members of Congress and officials in the Pentagon have both noted that Russia and China are
pursuing hypersonic weapons, leading many to question whether the United States needs to
accelerate its efforts in response, or whether an acceleration of U.S. efforts might contribute to an
arms race and crisis instability.

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Contents
Introduction ................................................................................................................... 1
Policy Focus ............................................................................................................. 1
Mission and Programs ................................................................................................ 2
Background.................................................................................................................... 3
The Prompt Global Strike Mission (PGS) ...................................................................... 3
Rationale for the PGS Mission ............................................................................... 3
PGS and the U.S. Strategic Command ..................................................................... 6
Potential Targets for the PGS Mission...................................................................... 6
Conventional Ballistic Missiles and the PGS Mission...................................................... 7
Plans and Programs ....................................................................................................... 10
Air Force Programs.................................................................................................. 10
The FALCON Study ........................................................................................... 10
Reentry Vehicle Research and Warhead Options...................................................... 12
Missile Options .................................................................................................. 13
The Conventional Strike Missile ........................................................................... 13
Hypersonic Test Vehicle (HTV-2) ......................................................................... 15
ArcLight ........................................................................................................... 16
Army Advanced Hypersonic Weapon.......................................................................... 17
Navy Programs ....................................................................................................... 18
Reentry Vehicle Research .................................................................................... 18
Conventional Trident Modification........................................................................ 20
Submarine-Launched Conventional Prompt Strike................................................... 21
Legislative Activity.................................................................................................. 23
FY2003 and FY2004 .......................................................................................... 23
FY2005 ............................................................................................................ 24
FY2006 and FY2007 .......................................................................................... 24
FY2008 ............................................................................................................ 25
FY2009 ............................................................................................................ 27
FY2010 ............................................................................................................ 28
FY2011 ............................................................................................................ 28
FY2012 ............................................................................................................ 28
FY2013 ............................................................................................................ 29
FY2014 ............................................................................................................ 30
FY2015 ............................................................................................................ 31
FY2016 ............................................................................................................ 31
FY2017 ............................................................................................................ 32
FY2018 ............................................................................................................ 32
FY2019 ............................................................................................................ 33
FY2020 ............................................................................................................ 34
FY2021 ............................................................................................................ 34
FY2022 ............................................................................................................ 35
Issues for Congress ....................................................................................................... 35
Assessing the Rationale for CPGS.............................................................................. 35
The Need for Prompt Response ............................................................................ 35
Evolving Rationale ............................................................................................. 36
The Potential for Misunderstanding a CPGS Missile Launch .......................................... 38

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Mitigating the Risks............................................................................................ 38
Remaining Concerns........................................................................................... 39
Reviewing the Alternatives ....................................................................................... 40
Land-Based Ballistic Missiles .............................................................................. 40
Submarine-Launched Ballistic Missiles ................................................................. 41
Long-Range Bombers ......................................................................................... 42
Tomahawk Cruise Missiles .................................................................................. 43
Hypersonic Cruise Missiles.................................................................................. 43
Scramjet Technologies ........................................................................................ 43
Arms Control Issues................................................................................................. 44
Potential Threats from Russia and China ..................................................................... 46
Weighing the Benefits and Risks ................................................................................ 49

Contacts
Author Information ....................................................................................................... 50
Acknowledgments......................................................................................................... 50

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Introduction
Members of Congress and Pentagon officials have placed a growing emphasis on U.S. programs
to develop hypersonic weapons as a part of an effort to acquire the capability for the United
States to launch prompt attacks against targets around the world. Hypersonic weapons, like all
long-range ballistic missiles, can travel faster than Mach 5, or about 1 mile to 5 miles per second. 1
The interest in these weapons is driven by both the perceived mission need for conventional
prompt strike systems and concerns about falling behind Russia and China in the development of
these technologies. 2 The United States is pursuing two key technologies for this purpose: boostglide systems that place a hypersonic glide vehicle (HGV) atop a ballistic missile booster or
shorter-range rocket systems, and hypersonic cruise missiles that would use scramjet
technologies. 3

Policy Focus
This report focuses, primarily, on the Pentagon’s ongoing program to develop ballistic missilebased conventional prompt strike systems. This effort has been underway for nearly 20 years. The
George W. Bush Administration demonstrated an interest in the use of conventional weapons for
precision, long-range strike missions in the 2001 Nuclear Posture Review (NPR). This study
called for the integration of precision conventional weapons with strategic nuclear forces in a new
category of “offensive strike” weapons. 4 Several other Pentagon studies published during the
Bush Administration also called on the United States to develop the capability to attack targets
around the world, in under an hour, with conventional warheads.
The Obama Administration, in the 2010 NPR, also emphasized the role that long-range, nonnuclear 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,”5 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.
The Trump Administration’s Nuclear Posture Review did not address the role of advanced
conventional weapons in U.S. nuclear posture, but the Administration has shown continuing
support for the development of long-range precision conventional weapons, with significant
increases in funding in its budget requests since FY2019. It also supported a joint Air
Force/Navy/Army effort to develop and deploy hypersonic capabilities by the early 2020s. 6
1 Jason L. Sherman, “T he Hypersonic Arms Race Heats Up,” The Daily Beast, December 3, 2017,

https://www.thedailybeast.com/the-hypersonic-arms-race-heats-up. See, also, Paul McCleary, “ China Loves DoD
Acquisition Culture, Says R&D Chief Griffin,” Breaking Defense, March 6, 2018, https://breakingdefense.com/2018/
03/china-loves-dod-acquisition-culture-says-r/.
2
“HASC Seapower Chair Wittman Presses For Hypersonic Focus,” Breaking Defense, February 22, 2018,
https://breakingdefense.com/2018/02/hasc-seapower-chair-wittman-presses-for-hypersonic-focus/.
3 For a summary of current U.S. hypersonic weapons programs, see CRS Report R45811, Hypersonic Weapons:

Background and Issues for Congress, by Kelley M. Sayler.
4 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.
5 U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34,

https://dod.defense.gov/Portals/1/features/defenseReviews/NPR/2010_Nuclear_Posture_Review_Rep ort.pdf.
6 Steve T rimble and Guy Norris, “Sandia’s Swerve Could Lead T o First -gen Hypersonic Production Line,” Aviation

Week, October 11, 2018, http://aviationweek.com/air-dominance/sandia-s-swerve-could-lead-first-gen-hypersonicproduction-line.

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Moreover, Michael Griffin, the former Under Secretary of Defense for Research and Engineering,
spoke often about the challenges presented by Russian and Chinese hypersonic weapons
programs and about the need for the United States to accelerate its efforts. In testimony before
Congress, he noted that the United States does not “have systems which can hold them at risk in a
corresponding manner, and we don’t have defenses against those systems.” He said, “It is among
my very highest priorities to erase that disadvantage, creating our own systems to hold them at
risk and to provide defense.”7

Mission and Programs
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.
During the George W. Bush Administration, analysts began to note that long-range ballistic
missiles armed with conventional warheads would be an ideal weapon for this mission. They
argued that these weapons, based in the United States or on submarines at sea, could attack
targets worldwide with a high degree of precision in a short amount of time. However, during the
latter years of the Bush Administration and the early years of the Obama Administration, DOD’s
programs began to focus on hypersonic glide vehicles mounted on rocket boosters 8 as the
technology of choice for this mission. In addition, in 2012, the Pentagon changed the focus of the
program from “prompt global strike” to “prompt strike,” which allowed the program to consider
the deployment of a hypersonic glider on a sea-based intermediate-range missile. The Pentagon is
also conducting research, through DARPA and the Air Force, into shorter-range, air-delivered,
hypersonic cruise missiles.
Some analysts 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. Some have also questioned whether the United States should accelerate its
hypersonic glide vehicle and prompt strike programs in response to Russian and Chinese
programs. Some argue that the United States should not only focus on maintaining a
7 Christian Davenport, “Why the Pentagon fears the U.S. is losing the hypersonic arms race with Russia and China,”

Washington Post, June 8, 2018, https://www.washingtonpost.com/business/economy/why-the-pentagon-fears-the-us-islosing-the-hypersonic-arms-race-with-russia-and-china/2018/06/08/7c2c3b4c-57a7-11e8-b656a5f8c2a9295d_story.html?mkt_tok=eyJpIjoiWTJJelkySXhaRFl5T kRNeSIsInQiOiJRazRKdXVNSnlSeU 1DZlBBS1 V
XUG1WYXFSZEtIN1wvRDBxb1lSV1 wvMUpT OGV2WT lpeDVWR0g3ZUdHK0N3UDN1QlJzcXNvSG1oUHBlcHl
hSmlZYUhDSysrU3I2SlN2T mJT K3J1RWRtNEQ5NjFJN1dmaU9UME54N1JZbEZhZ0Q0c2c2In0%3D&utm_term=.
57f7b133e662.
8 Many analysts refer to these boost -glide systems as “hypersonic weapons” because the booster can deliver a gliding

reentry vehicle to its target at hypersonic speeds. However, all ballistic missiles, even those armed with reentry vehicles
that cannot glide to targets, travel at hypersonic speeds. T he difference with these new types of systems is not their
speed but their ability to change course and maneuver after launch, either to evade missile defenses or to improve their
accuracy upon approach to their targets.

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technological edge in this area, but should also counter Russian and Chinese hypersonic weapons
with similar U.S. weapons. Others, however, argue that an “arms race” in hypersonic weapons
could be destabilizing, as the weapons’ speed would shorten attack and response times and could
possibly prompt early use during a crisis.
Congress has generally supported the rationale for the prompt strike mission. In the past, it has
restricted funding and suggested changes in the direction of specific programs, but, recently, it
has pressed the Pentagon to place a higher priority on the program and to accelerate its
development. Congress is likely to continue to review the technologies and programs related to
this mission as a part of the annual authorization and appropriations process.
This report provides an overview of the rationale for the PGS/prompt strike 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, and 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, 9 or with forces that have the range to reach targets
across the globe from wherever they are deployed. This would not only allow the United States to
pursue an adversary without relying on forward bases, it would also allow the United States to
reach targets deep inside an enemy’s territory if that area were out of the range of U.S. forces
deployed at bases or on naval forces in the region. Moreover, if an adversary developed air
defenses or other capabilities that could deny U.S. aircraft access to critical targets, a long-range
strike capability based on ballistic missile technologies could prove valuable if launched early, as
a “leading-edge” capability that degraded an opponent’s defenses. Analysts argue that these types
9 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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of systems would be far less sensitive to an adversary’s anti-access and area denial (A2/AD)
efforts.
Further, some analysts argue that the United States must be able to attack targets across the globe
in a matter of hours or less, either at the start of a conflict or during ongoing operations. This is
because U.S. adversaries might adapt to the U.S. precision-strike capability by denying targeting
information with concealment techniques or mobility, leaving the United States with little time to
attack after it identified relevant targets. Moreover, many have noted that adversaries could seek
to protect their assets by deploying them in buried or hardened facilities, leading to a requirement
for improvements in the U.S. ability to defeat hardened and deeply buried targets promptly,
before the adversary employed the hidden capabilities.
The need for prompt long-range, or global, strike capabilities was 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.”10 The 2006 QDR expanded on the need for prompt
global strike capabilities, noting that they would provide the United States with the ability “to
attack fixed, hard and deeply buried, mobile and relocatable targets with improved accuracy
anywhere in the world promptly upon the President’s order.” This QDR went on to call for the
deployment of a prompt global strike capability, using Trident submarine-based ballistic missiles
armed with conventional warheads, within two to four years.11 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.”12
DOD 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 highpayoff 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. 13
Officials in the George W. Bush Administration viewed the prompt global strike mission as a
means to extend the U.S. capability to address global contingencies that could threaten U.S.
security and U.S. interests. For example, Admiral James O. Ellis, the commander of U.S.
Strategic Command (STRATCOM) from 2002 to 2004, explained that PGS would “provide a
wider range of options to the President in responding to time-critical global challenges.”14
10 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, September 29, 2001, p. 43,

http://www.comw.org/qdr/qdr2001.pdf.
11

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.
12 U.S. Department of Defense, Quadrennial Defense Review Report, Washington, DC, February 2010, pp. 32-33,
http://archive.defense.gov/qdr/QDR%20as%20of%2029JAN10%201600.pdf .
13 T his 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.
14 Statement of Admiral James O. Ellis, Commander, U.S. Strategic Command, House Armed Services Committee,

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General James Cartwright, who served as commander of STRATCOM between 2004 and 2007,
defined the global strike mission by stating that “it provides to the nation the ability to rapidly
plan and rapidly deliver effects anyplace on the globe.” The capability would not necessarily be
nuclear, and a regional combatant commander could “tailor it for his target and deliver it very
quickly, with very short time lines on the planning and delivery, any place on the face of the
Earth.”
General Cartwright also emphasized that the global strike capability involved much more than
just the delivery of a weapon to a target, stating that “it encompasses both the ability to plan
rapidly, to apply the precision to the intelligence and gather that intelligence in a very rapid
manner, and then to apply that intelligence to the target and understand the effect we want to
create.”15 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.16 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 focused 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.”17 This
change in focus was reflected in Pentagon guidance in 2012; the program was then known as
Conventional Prompt Strike (CPS), rather than Conventional Prompt Global Strike (CPGS).
The Trump Administration did not address either a prompt global strike or prompt strike mission
in its National Defense Strategy or its Nuclear Posture Review. However, it has continued to
support funding for hypersonic glide technologies in its defense budget requests. Funding
requests have increased from $181.3 million for Defense-wide Prompt Global Strike Capability
Development in FY2017 to $3.2 billion for Army, Navy, and Air Force programs in FY2021. 18
Michael Griffin, when serving as the Pentagon’s Under Secretary for Research and Engineering,
emphasized that the Pentagon did intend to place a high priority on pursuing U.S. prompt strike
programs. 19

March 13, 2003.
15 U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, T estimony of Admiral James E.
Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005.
16 Grossman, Elaine, M., “Hayden: ‘Prompt Global Strike’ Raises Bar for Intel Community.” Inside The Air Force.

June 22, 2007.
17 U.S. Department of Defense, Nuclear Posture Review, Washington, DC, April 6, 2010, p. 34,
https://dod.defense.gov/Portals/1/features/defenseReviews/NPR/2010_Nuclear_Posture_Review_Report.pdf .
18

U.S. Department of Defense, Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer,
Defense Budget Overview, Washington, DC, February 2020, p. 1-8.
19 Paul McCleary, “ China Loves DoD Acquisition Culture, Says R&D Chief Griffin ,” Breaking Defense, March 6,

2018, https://breakingdefense.com/2018/03/china-loves-dod-acquisition-culture-says-r/.

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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. 20 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. 21 This change in the command structure
highlighted the growing emphasis on long-range, strategic missions in conventional warfighting
doctrine.
In July 2006, STRATCOM established its joint functional component command for global strike
(JFCC-GS). According to its mission statement, JFCC-GS “is designed to optimize planning,
execution and force management for the assigned missions of deterring attacks against the United
States, its territories, possessions and bases.” Among other tasks, it “provides integrated global
strike capabilities to deter and dissuade threats and when directed, defeat adversaries through
decisive joint global kinetic and non-kinetic combat effects.”22

Potential Targets for the PGS Mission
Analysts 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. 23 For example, if an
adversary deployed air defense or antisatellite weapons that could disrupt the U.S. ability to
sustain an attack, the United States might choose to strike promptly at the start of a conflict with
weapons that could penetrate and destroy the defenses. A prompt strike against an adversary’s
ballistic missiles or caches of weapons of mass destruction (WMD) might allow the United States
to destroy these weapons before an adversary could use them. The United States might also use
prompt, long-range weapons to attack an adversary’s command and control capabilities, to
degrade or undermine its operations early in a conflict.
The United States might also be faced with circumstances during an ongoing conflict when it
would need to destroy targets that could appear quickly and remain vulnerable for short periods
of time. These might include leadership cells that could move during a conflict or mobile military
systems that the adversary had chosen to keep hidden prior to their use. These types of targets
might only be vulnerable to weapons that the United States could launch promptly and direct to
their targets quickly. Analysts have noted that PGS might provide the means to attack such targets
if the United States did not have the necessary weapons located near the conflict.

20 U.S. Department of Defense, “DOD Announces Merger of U.S. Space and Strategic Commands,” June 26, 2002.
21 According to Admiral James O. Ellis, the Commander of ST RAT COM, 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 Stat ement of Admiral James O. Ellis, Commander United States Strategic Command, before the
House Armed Services Committee, March 13, 2003, p. 4.
22 http://www.stratcom.mil/factsheets/gs/.
23 A description of some of these scenarios can be found in the National Academies Study on Prompt Global Strike.

See Committee on Conventional Prompt Global Strike Capability, National Research Council of the National
Academies, U.S. Conventional Prompt Global Strike: Issues for 2008 and Beyond, Washington, DC, 2008, pp. 31-33.

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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.”24 These scenarios included several cases:


A near-peer competitor had used its emerging counterspace 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.

Each of these cases provided scenarios where the United States might want to attack promptly at
the start of, or during, a conflict with a regional adversary. However, as some analysts have noted,
long-range prompt strike weapons may not always prove the best solution in all circumstances.
Even if the weapon could arrive within a relatively short amount of time, the United States might
not have the intelligence needed to pinpoint the target, particularly if it were moving. Moreover,
an adversary might detect the launch of the weapon and move it before the weapon arrived. As a
result, in some cases, a weapon that could loiter in or near the area of the conflict, and strike
within minutes when the target became evident, may be better than a weapon that could launch
promptly but might take more than an hour to arrive. 25 The need for prompt, but regional, attack
capabilities seems to be part of the rationale for the Pentagon’s interest in developing hypersonic
capabilities for medium- and intermediate-range delivery systems.

Conventional Ballistic Missiles and the PGS Mission
The Obama Administration noted, in the 2010 NPR, that the Pentagon “is studying the
appropriate mix of long-range strike capabilities, including heavy bombers as well as non-nuclear
prompt global strike, in follow-on analysis to the 2010 QDR and the NPR.” The United States
might use a number of different weapons systems for this purpose. In the near term, these could
include medium- or long-range aircraft, cruise missiles launched from bombers or submarines,
and ballistic missiles based at sea or on land in the United States. 26 But conventional aircraft,
24

U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, T echnology and Logistics,
Time Critical Conventional Strike from Strategic Standoff, Report of the Defense Science Board T ask Force,
Washington, DC, March 2009, p. 2, https://www.acq.osd.mil/dsb/reports/2000s/ADA498403.pdf.
25 For a description of a range of possible scenarios, and the different requirements for prompt response, see James M.
Acton, Silver Bullet? Asking the Right Questions About Prompt Global Strike (Washington, DC: Carnegie Endowment
for International Peace, 2013), pp. 9-29.
26 In his testimony in 2003, Admiral Ellis specifically mentioned two systems that could contribute to this mission,

T rident submarines reconfigured to carry T omahawk 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 scr amjets, for long-range
attack term. T hese hypersonic aircraft, which could fly at speeds of Mach 2 -Mach 5, are still in the early stages of
development. T hey are envisioned to launch from air bases, like aircraft, but to travel at speeds that far exceed th ose of
U.S. aircraft and may approach the speeds of missiles. See, for example, Pincus, Walter, “Pentagon Has Far-reaching

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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 suggested that the United States should use long-range ballistic
missiles (ICBMs and SLBMs) for the prompt global strike mission. 27 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.28 To use
them for the conventional prompt global strike mission, the United States would have to deploy
these missiles with conventional warheads. The Bush Administration first raised the profile of
long-range, conventional strike missiles in the 2001 NPR, when it introduced the concept of the
“new triad.” This concept joined long-range nuclear-armed missiles with precision-strike
conventional weapons in a category called offensive strike weapons. The Bush Administration
argued that the availability of precision conventional weapons would, possibly, provide the
President with more options in a crisis, and, therefore, reduce the likelihood of the use of nuclear
weapons.
The Pentagon’s Defense Science Board (DSB), in a study published in early 2004, asserted that
land-based long-range ballistic missiles have “unique, time-critical characteristics” that include
“responsiveness, range, speed, precision, lethality, and freedom of maneuver.”29 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”30 by allowing the United States to choose
Defense Spacecraft in Works,” Washington Post, March 16, 2005. p. 3.
27 See, for example, U.S. Department of Defense, Office of the Un der Secretary of Defense for Acquisition,

T echnology, 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.
28
When the Cold War ended in the early 1990s these missiles carried more than 8,000 nuclear warheads. T he 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,
https://2009-2017.state.gov/t/avc/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.
29 U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, T echnology, and Logistics,

Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1.
30 U.S. Congress, Senate Committee on Armed Services, Subcommittee on Strategic, T estimony of Admiral James E.

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conventional rather than nuclear weapons to attack some categories of targets. By replacing some
nuclear weapons with conventional weapons in the U.S. strategic war plan the United States
might be able to further reduce its reliance on, and, therefore, its number of deployed strategic
nuclear weapons. 31
General Cartwright and others emphasized that the substitution of conventional warheads for
nuclear warheads in the U.S. war plan would require significant improvements in the accuracy of
U.S. long-range ballistic missiles. If missiles could deliver their payloads more precisely to their
targets, then, for some categories of targets, they may not need the explosive yield of a nuclear
weapon to destroy the target. Both the Navy and the Air Force have explored advanced guidance
and targeting technologies, such as the use of GPS (global positioning systems), to provide their
missiles with these improvements in accuracy. This effort had been underway for more than two
decades. After General Cartwright sought a study that would allow him to determine what
proportion of the targets in the U.S. war plan could be attacked with conventional weapons, an
industry analyst estimated that this proportion could be between 10% and 30% of the existing
targets. 32
Subsequently, however, some analysts and military officials questioned whether the United States
should seek to substitute conventional warheads for nuclear warheads in the U.S. nuclear war
plan. They noted that conventional warheads might lack the deterrent capabilities of nuclear
warheads, even if they could damage many targets, because they lack the psychological effects
associated with nuclear weapons. According to General Kevin Chilton, the former commander of
STRATCOM, this would not be a weapon that “engenders fear, compared to the threat of a
nuclear strike.” Instead, General Chilton and other analysts viewed long-range ballistic missiles
armed with conventional warheads as a “niche” weapon that might be used to attack some critical
targets in scenarios that would not have otherwise called for the use of nuclear weapons. 33
In other words, instead of substituting for nuclear weapons, a new prompt global strike capability
would expand the range of U.S. conventional options. For example, General Chilton noted, in
2008 testimony before the Strategic Forces Subcommittee of the House Armed Services
Committee, that this type of weapon could “provide an additional arrow in the quiver, if you will,
of the country to address emerging threats, that we might find a nuclear weapon application to be
self-deterring to address that threat.”34 Even without direct substitution, however, CPGS still
might reduce U.S. reliance on nuclear weapons, because, with more conventional options, a
President might be less likely to authorize the use of a nuclear weapon to attack a critical target.
The idea that long-range systems armed with conventional warheads could enhance deterrence
remained evident in the discussion about a potential CPGS capability during the Obama
Administration. In February 2012, James Miller, then the Under Secretary of Defense for Policy,
noted that programs like CPGS could help strengthen U.S. non-nuclear forces as a part of the U.S.
deterrent. 35 But, as had been evident in other discussions at the time, he referred to these systems’
Cartwright, Commander, U.S. Strategic Command, Hearing, April 4, 2005.
31 Grossman, Elaine M., “U.S. General: Precise Long-Range Missiles may Enable Big Nuclear Cuts,” Inside the

Pentagon, April 28, 2005.
32 Ibid.
33 Carlo Munoz, “Chilton: Conventional PGS Cannot Replace Nuclear Deterrent Role,” Inside the Air Force, January

22, 2010.
34 U.S. Congress, House Armed Services, Strategic Forces, United States Strategic Posture and the Fiscal Year 2009

Budget Request for Strategic Programs, Hearing, 110 th Cong., 2 nd sess., March 27, 2008.
35 Elaine M. Grossman, “Conventional Arms No Substitute for Nuclear: Strategic Command Official,” February 29,

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ability to enhance U.S. conventional capabilities rather than their ability to substitute directly for
nuclear weapons.
The Pentagon continues to emphasize the role that conventional prompt strike weapons could
play in enhancing U.S. conventional war-fighting capabilities. The Navy, in its FY2022 budget
request, notes that its conventional prompt strike program will enable “precise and timely strike
capabilities in contested environments across multiple platforms.” The Pentagon’s focus on
deploying hypersonic glide vehicles on shorter and intermediate-range missiles is also an effort to
bolster conventional war-fighting capabilities. The FY2020 budget briefing noted that these types
of systems will help U.S. warfighters “maintain tactical advantage” on the battlefield. 36

Plans and Programs
Both the Air Force and the Navy have studied the possible deployment of conventional warheads
on their long-range ballistic missiles in the past. The Air Force briefly studied the penetration
capabilities of conventional ICBMs in the mid-1990s. In August 1995 it launched an ICBM
armed with a “pointy” front end (and no explosive warhead) against a granite slab that had
characteristics similar to reinforced concrete. Press reports indicate that the warhead entered the
target at a 90 degree angle and penetrated to a depth of 30 feet, which is greater than the depth of
penetration of any existing U.S. weapon. 37 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.
During the George W. Bush Administration, the Air Force and the Navy both pursued programs
that would provide a prompt global strike capability. However, in FY2008, Congress eliminated
funding for the Navy and Air Force programs, creating, instead, 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. The program was to
fund the design, development, and acquisition of guidance systems, boosters, mission planning
capabilities, mission enabling capabilities, reentry systems, and payload delivery vehicles
(PDVs). 38 Details on funding for this account are described below.

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 c ontinental United States) that
was designed to develop both a launch vehicle similar to a ballistic missile and a hypersonic
2012.
36 U.S. Department of Defense, Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer,
Defense Budget Overview, Washington, DC, February 2020, p. 1-2.
Grossman, Elaine M. “Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs,” Inside the Pentagon,
June 27, 2002, p. 1.
37

38 FY 2011 RDT &E Budget Item Justification, PE 0604165D8Z.

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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. 39 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 1 hour of its launch. 40 These characteristics would provide it with the
capabilities needed to attack time-sensitive targets. 41
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 proposed a plan to segregate the
missiles armed with conventional warheads and deploy them far from bases with nuclear
warheads. The missiles could be deployed “on mobile launchers or in semi-buried silos or berms
on each coast, ready to launch on short notice.”42 The two potential bases noted in the study were
Vandenberg Air Force Base on the West Coast and Cape Canaveral on the East Coast.
Analysts 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.

39 DARPA, “FALCON (Force Application and Launch from CONUS T echnology Dem onstration 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 T hreats,” Washington Post, March 16, 2005, p. 3.
40 Report to Congress on the “Concept of Operatio ns” for the Common Aero Vehicle, Submitted in response to
Congressional Reporting Requirements, by Peter B. T eets, Under Secretary of the Air Force, February 24, 2004. p. 2.
41

T his 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. T h ese capabilities would be needed for the PGS
mission, regardless of the munitions package on the ballistic missile.
42 Air Force Space Command, Common Aero Vehicle White Paper.

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As is noted below, the Falcon study, and the proposed CAV hypersonic vehicle, became the
foundation for the Hypersonic Technology Vehicle (HTV). While this vehicle served, initially, as
the leading contender for a hypersonic glider for the CPGS mission, it was sidelined after two
failed tests in the 2010 and 2011. Nevertheless, the Air Force has continued to pursue the
development of a vehicle similar to the HTV, now known as the Tactical Boost Glide (TBG)
system, which would be launched on a modified version of the Army’s Tactical Missile System
(ATacMS). 43 This will also serve as the glide vehicle launched on the Air Force air-launched,
rapid-response weapon (ARRW), which is described in more detail below.

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. 44 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. 45 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.”46 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.
In addition, as was noted above, the United States could use a hypersonic glide vehicle as the
reentry body on a long-range ballistic missile. According to the Falcon Study, the CAV would
have been an unpowered, maneuverable hypersonic glide vehicle capable of carrying
approximately 1,000 pounds in munitions or other payload. 47 This vehicle would have had 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 funded this program, beginning in 2008, through the defense-wide Conventional
Prompt Global Strike (CPGS) program.
Initially, the Air Force considered two types of warheads for the CPGS mission. 48 One of these
would contain kinetic energy projectiles, like the flechettes described below (see “Conventional
Trident Modification”), 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 also be
delivered by a hypersonic glide vehicle should such a system become operational. However, if the
43 Steve T rimble and Guy Norris, “Sandia’s Swerve Could Lead T o First -gen Hypersonic Production Line,” Aviation

Week, October 11, 2018, http://aviationweek.com/air-dominance/sandia-s-swerve-could-lead-first-gen-hypersonicproduction-line.
44

U.S. Department of Defense, Office of the Under Secretary of Defense for Acquisition, T echnology, and Logistics,
Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-1.
45 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004. p. 5-3.
46

Eric Schmitt, “U.S. Considers Conventional Warheads on Nuclear Missiles,” New York Times, February 24, 2003.

47 In 2006, the Bush Administration redesignated the CAV as the hypersonic technology vehicle, in response to the

restrictions in the FY2005 Defense Appropriations Act .
48 Major Jason E. Seyer, USAF, “Adding the Conventional Strike Missile to the U.S.’s Deterr ence T oolkit,” High
Frontier, February 2009, p. 32.

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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 have been 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 renamed the modified Minuteman and Peacekeeper missiles, referring to them as
Minotaur missiles. The Minotaur IV missile would use three stages from the Peacekeeper missile
and a new fourth stage developed by Orbital Sciences Corporation. The Minotaur IV missile
could serve as the boost vehicle for a land-based CPGS mission. When it began to consider the
use of these missiles for the PGS mission, the Air Force stated that the modifications could be
made at a relatively low cost and low level of technical risk because they would use the missiles ’
existing rocket motors. The avionics and guidance systems could rely, primarily, on existing
technologies, with some modifications to allow the upper stages of the missiles and their reentry
vehicles to maneuver for improved accuracy. The Air Force also indicated that a modified
Peacekeeper missile would be able to carry much larger payloads than the Trident missile. 49
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. 50 These include a long-range land-based option, a shorter-range forward
deployed land-based missile, a sea-based option, and an air-breathing option. The Air Force
completed this study in 2008. 51

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, 52 but after
Congress refused to fund development of the CTM, the CSM became the earlier option for the
49

Michael Sirak, “ Air Force Envisions Mid-T erm, Prompt Global Strike Missile,” Defense Daily, July 7, 2006.

50 Carlos Munez, “ Services Collaborate on Long-T erm Prompt Global Strike Study.” Inside the Navy, September 10,

2007.
Emelie Rutherford, “AoA for Prompt Global Strike to go to JROC this Summer, Chilton Says,” Defense Daily,
March 5, 2008.
51

52 Elaine M. Grossman. “‘Conventional Strike Missile’ Proposed as Midterm Global Option,” Inside Defense, April 6,

2006.

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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. 53 According to DOD, the CSM was, at that time, the “lead design to demonstrate a
possible materiel solution for the CPGS warfighting capability gap.”54
According to DOD, the CSM would have been 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. 55 The CSM would not follow the standard ballistic
trajectory of nuclear-armed ballistic missiles. Its booster would launch with a lower-profile, or
depressed, trajectory. The payload delivery vehicle (PDV), after separating from the launch
vehicle, could maneuver to its target. This would not only provide it with high accuracy, it would
be able to maneuver to avoid overflight of third-party countries. 56 With these capabilities, the
CSM might mitigate some of the concerns about nuclear ambiguity raised by Congress during its
review of the CTM program.
According to Air Force plans, the CSM would have combined the Minotaur IV launch vehicle
described above with a hypersonic payload delivery vehicle (PDV). 57 The first PDV would have
been a weaponized version of the DARPA/Air Force HTV-2 vehicle. As an alternative, it could
have been based on the Army advanced hypersonic weapon (AHW) that is described below. 58
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. 59 These dates slipped, however, and,
according to DOD officials, the program did not have an official deployment date because DOD
had not concluded the research, development, and testing programs for the possible reentry
bodies. DOD was not prepared to decide which technology would be deployed until the reentry
bodies had been tested in five demonstration flights. This has not yet happened, and may not
happen until later in the decade. 60

Elaine M. Grossman, “Chilton Shifts Prompt Strike Priority to the Air Force,” Global Security Newswire, September
3, 2008.
54 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/Portals/45/Documents/
defbudget/fy2011/budget_justification/pdfs/03_RDT _and_E/OSD%20RDT E_PB_2011_Volume%203B.pdf.
53

55 Major Jason E. Seyer, “Adding the Conventional Strike Missile to the US’s Deterrence T oolkit,” High Frontier,

February 2009.
56 Major Jason E. Seyer, “ Adding the Conventional Strike Missile to the US’s Deterrence T oolkit,” High Frontier,
February 2009.
57 Grossman, Elaine M. “U.S. Military Eyes Fielding “Prompt Global Strike” Weapon by 2015,” Global Security

Newswire, July 1, 2009.
According to DOD, “the Army Hypersonic Glide Body (HGB) design provides an alternative risk reduction path
within the Air Force CSM concept.” See U.S. Department of Defense, Fiscal Year 2011 Budget Estimates, Research
Development, Test and Evaluation. Defense Wide, Washington, DC, February 2010, p. 257,
http://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2011/budget_justification/pdfs/03_RDT _and_E/
OSD%20RDT E_PB_2011_Volume%203B.pdf.
58

Elaine M. Grossman, “U.S. Military Eyes Fielding ‘Prompt Global Strike’ Weapon by 2015,” Global Security
Newswire, July 1, 2009.
59

60 Elaine M. Grossman, “Cost to T est Global-Strike Missile could Reach $500 Million,” Global Security Newswire,

March 15, 2010.

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Hypersonic Test Vehicle (HTV-2)
DARPA developed the Hypersonic Test Vehicle as a part of the Falcon program described above.
Unlike the CAV, which would have been a spherical hypersonic glider, the HTV-2 was shaped
like a wedge. DARPA indicated that the goal for the HTV-2 program was to develop a vehicle
that could launch into the Earth’s upper atmosphere and descend across the Pacific Ocean with
speeds of more than 13,000 miles per hour. It hoped to design it to travel from Vandenberg Air
Force Base to a target near Kwajalein Atoll in the Pacific Ocean in 30 minutes. Lockheed Martin
Corporation developed the HTV-2, using many of the concepts and technologies developed for
the E2 warhead, described below. 61 DARPA planned to acquire and test two vehicles. The Air
Force also contracted with Lockheed Martin to produce a third vehicle, which the Air Force
planned to use as the PDV in a test of the CSM’s ability to deliver a weapon to the target.
In FY2008, when Congress established the defense-wide conventional prompt global strike
program with a budget of $100 million, DOD allocated $56 million to hypersonic glide
experiments and concept demonstration development. This is the portion of the budget that
supported the development and testing of the HTV-2. This program area received an additional
$42 million in FY2009 and $90 million in FY2010. The Obama Administration requested an
additional $136.5 million for this program area in FY2011. According to DOD’s budget request,
it planned to use these funds to conduct the HTV-2 flight experiments, finalize design concept for
the CSM payload delivery vehicle, complete qualification of a Minotaur launch vehicle for a
CPGS mission, and mature/demonstrate technologies associated with the high speed
demonstration of conventional munitions. DOD also indicated that it would use funding in this
program area to procure the PDV warhead and booster that the Air Force would use in the
planned CSM “weaponized” flight test. 62
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. 63 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. 64 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. 65 DOD reviewed the results of the April 2010 test, in
an effort to determine what caused the vehicle to fail during its flight. 66 It also conducted a

61 Defense Advanced Research Projects Agency (DARPA_, Falcon Hypersonic Technology Vehicle 2 (HTV-2), Fact

Sheet, Washington, DC, April 15, 2010.
62 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/Portals/45/Documents/
defbudget/fy2011/budget_justification/pdfs/03_RDT _and_E/OSD%20RDT E_PB_2011_Volume%203B.pdf.
63

“Minotaur IV/HT V-2 Lifts Off,” Targeted News Service, May 20, 2010.

64 Defense Advanced Projects Agency (DARPA), Falcon HTV-2 Launch Test Hypersonic Vehicle Flight Capabilities,

Fact Sheet, Washington, DC, April 23, 2010.
Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider T est Failure,” Global Security Newswire,
August 19, 2010.
65

66 Elaine M. Grossman, “Pentagon Nears Finding on Hypersonic Glider T est Failure,” Global Security Newswire,

August 19, 2010.

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number of wind tunnel tests and computer simulations to optimize the vehicle design and flight
trajectory before the second test.
DOD conducted a second test of the HTV-2 vehicle on August 10, 2011. According to DARPA,
the Minotaur missile successfully boosted the HTV-2 vehicle onto the desired trajectory and the
HTV-2 vehicle successfully separated from the booster and transitioned to its “Mach 20
aerodynamic flight.” However, the HTV-2 then “experienced a flight anomaly post perigee.” This
prompted the system to make a “controlled descent and splash down in the ocean.”67 In other
words, DARPA lost contact with the HTV-2 vehicle after it began its independent flight along its
glide trajectory, and the vehicle crashed into the ocean. DARPA said that the test had important
successes, with the launching, separation, and initial trajectory of the vehicle, and that it collected
significant data during the flight. However, it had not yet determined how to control the
aerodynamic portion of the flight, after the HTV-2 separated from its booster. 68
According to DOD, in FY2011, it completed a finalized the design concept for the CSM payload
delivery vehicle and qualified the Minotaur launch vehicle for a CPGS mission analysis of launch
system infrastructure requirements utilizing other ballistic missile propulsion programs. However,
the combination of the poor test record and tight budget environment undermined the future of
this program. DOD allocated $51.8 million to this program area in FY2012 and requested an
additional $49.5 million for FY2013. Congress added funding to the CPGS program area in
FY2013; after sequestration, the budget totaled $176.4 million. However, only $23 million of this
was allocated to the HTV-2 program. Further, in its FY2014, FY2015, FY2016, and FY2017
budget requests, DOD sought only $2 million for this program area. The FY2018 budget request
included only $1 million. According to the budget documents, these funds will allow DOD to
conduct studies to evaluate system alternatives, and to continue aerodynamic and weapon risk
reduction and technology maturation efforts through ground and wind tunnel tests. DOD does
not, however, plan to conduct any additional flight tests of the HTV-2 vehicle.

ArcLight
DARPA also, for a time, sought to design a new system, known as ArcLight, to serve as an
alternative delivery vehicle for the PGS mission. The ArcLight program w ould 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.”69 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 have been launched from the Navy’s Mark 41 vertical launch
system, on both submarines and surface ships. It would have a shorter range than either the
Trident missile or the Air Force CSM. As a result, it would require forward positioning of Navy
assets. DOD requested $2 million for the ArcLight program in FY2010 and $5 million in FY2011.
However, it seems to have terminated the program and did not request any additional funding in
FY2012 or subsequent years. As is noted below, however, the Air Force has recently funded a
number of programs that may provide it with bomber-delivered, intermediate-range boost-glide
capabilities.

67

Defense Advanced Research Projects Agency, DARPA Hypersonic Vehicle Splash Down Confirmed , Washington,
DC, August 14, 2011, http://www.darpa.mil/NewsEvents/Releases/2011/2011/09/
11_DARPA_HYPERSONIC_VEHICLE_SPLASH_DOWN_CONFIRMED.aspx.
68 T hom Shanker, “Brief T est of Military Aircraft Said T o Yield Much Data,” New York Times, August 12, 2011.
69 Craig Hooper, “New Navy Missile Could Hit Global T argets,” Military.com , July 8, 2010.

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Army Advanced Hypersonic Weapon
The Army also developed 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 the HTV-2 and, therefore,
would 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 a precision guidance system.
Congress appropriated $1.5 million for the Army’s advanced hypersonic weapon in FY2006, and
added $8.9 million in FY2007. 70 DOD allocated $29 million of the combined fund for CPGS to
the Army’s program in FY2008, $13.9 million in FY2009, $46.9 million in FY2010, and $69
million for FY2011. Congress appropriated $91 million for this alternative in FY2012, and DOD
requested an additional $42 million for FY2013. As was noted above, Congress increased CPGS
funding in FY2013, and, after sequestration, the AHW portion of the budget received $147.8
million. Congress appropriated an additional $55 million for the AHW in FY2014, $90 million in
FY2015, and $86 million in FY2016. The FY2016 budget documents also indicated that DOD
expected funding to increase steadily in the next five years. Following this plan, DOD requested
$174 million for the AHW, now known as the Alternate Re-Entry System, in FY2017, $197.4
million in FY2018, and $263.4 million for FY2019. 71
The Army conducted a successful flight test of the AHW on November 17, 2011. 72 The system
launched from the Pacific Missile Range Facility in Hawaii, and used the strategic targets system
(STARS) booster stack, which is derived from the Navy’s Polaris ballistic missile. According to
press reports, the vehicle traveled 2,400 miles, from the Pacific Missile Range Facility in Hawaii
to Kwajalein Atoll. The test collected data on hypersonic boost-glide technologies and test range
performance. The mission also tested the thermal protection technologies for the vehicle, an area
where concerns exist because of the high temperatures generated during flight.
DOD initially indicated that the AHW program was a “risk mitigation effort in support of the Air
Force CPGS project” and was intended to “develop and demonstrate the capability of an
alternative payload delivery vehicle (APDV) through a two-flight test schedule.” However, after
the HTV-2 experienced difficulties in both its flight tests, and the AHW succeeded in its first test,
this system appeared to be the leading contender for the hypersonic glider portion of a boost-glide
conventional prompt strike system.
DOD conducted a second flight test of AHW system on August 25, 2014. 73 During this test, DOD
launched the vehicle from the Kodiak Launch Complex off Alaska and planned to fly it to the test
range at Kwajelein Atoll in the South Pacific. 74 However, controllers destroyed the weapon four
seconds after launch after detecting problems with the STARS booster. With this failure early in
the flight, the test provided no information about AHW glider and did nothing to advance the
70 Elaine M. Grossman, “Army Eyes Advanced Hypersonic Weapon,” Inside Defense, January 5, 2007.
71 T he FY2019 budget documents list the request of $263.414 million in PE164: Hypersonic Glide Experiment and

Concepts Demonstration Support, which had supported the HT V-2 program and had been reduced to only $1 million in
FY2018. However, in the program description narrative, the documents indicate that “all of FY2019 funding will be
allotted to P166, Alternate Re-Entry System/Warhead Engineering,” which supports the AHW program.
72 Ann Roosevelt, “First T est Flight Successful for Advanced Hypersonic Weapon Vehicle,” Defense Daily, November
18, 2011, p. 6.
73 Colin Clark, “Hypersonic Weapons Face Major Milestone in August

T est,” Breaking Defense, March 18, 2014.

74 Bill Gertz, “Army Hypersonic Missile Fails in Second T est,” Washington Free Beacon, August 25, 2014.

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program. 75 Reports indicate that the Army has determined that failure was caused by an “external
thermal protective cover designed to regulate motor temperature,” which “interfered with the
launch vehicle steering assembly.”76 Neither the booster nor the hypersonic vehicle contributed to
the test’s failure.
DOD scheduled a third flight experiment, using a “scaled” version of the Advanced Hypersonic
Weapon, for 2017. Although the test was conducted from land in Hawaii, the scaled version of the
vehicle was sized to fit on a submarine-launched ballistic missile. As is noted below, this test was
conducted, successfully, in late October, 2017.
In 2018, the Pentagon indicated that the Army, Navy, and Air Force would work together to
develop and deploy the AHW as a common hypersonic glide vehicle by the early 2020s. 77 This
vehicle is now known as the Common Hypersonic Glide Body, or C-HGB. The Navy will deploy
it as a part of its submarine-launched Conventional Prompt Strike (CPS) program, and the Army
will deploy it on the Long Range Hypersonic Weapon (LRHW) system. The Air Force had
planned to deploy this glide vehicle on a system known as the Hypersonic Conventional Strike
Weapon (HCSW/Hacksaw), but eliminated funding for this program in its FY2021 budget
request. 78 The Air Force is, instead, focusing its hypersonics program on the ARRW system,
which will carry the tactical boost glide reentry vehicle (TBG) derived from the HTV-2 program.

Navy Programs
Reentry Vehicle Research
In FY2003, the Navy requested funding for research on a new type of guided reentry vehicle that
could significantly improve the accuracy of the Trident II (D-5) missiles. This program, known as
the enhanced effectiveness (E2) initiative, included an initial funding request of $30 million, a
three-year study, and a full-scale flight test in early 2007. 79 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. 80 A standard MK4 reentry vehicle, which is the reentry vehicle deployed on
75 Andrea Shalal and David Alexander, “Experimental U.S. Hypersonic Weapon Destroyed Seconds After Launch,”

Reuters, August 25, 2014.
76 Jason Sherman, “DOD Plans FY-17 ‘Flight Experiment’ Of Hypersonic Weapon,” Inside Defense, February 5, 2015.
77 According to press reports, t he Navy is designing the common glide vehicle. T he Army will develop the prototypes

for flight testing and Sandia National Laboratories, the designer of the original concept, th en will build the common
glide vehicles. See Steve T rimble and Guy Norris, “Sandia’s Swerve Could Lead T o First -gen Hypersonic Production
Line,” Aviation Week, October 11, 2018, http://aviationweek.com/air-dominance/sandia-s-swerve-could-lead-first-genhypersonic-production-line.
78
T he HCSW would have been a solid-rocket-powered, air-launched, GPS-guided system. It was expected to reach
initial operational capability on existing combat aircraft in FY2022. See Guy Norris, “B-52 Readied for Intense
Hypersonic Weapons T est and Deployment Role,” Aviation Week and Space Technology, August 29, 2018.
Norris, Robert S. and Hans M. Kristensen. “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,
January/February 2005, pp. 73-75.
80
According to the Defense Science Board T ask 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.
79

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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 improve the lethality of the nuclear warheads, but it would also permit the
missiles to destroy some types of targets with conventional warheads.81
Lockheed Martin flew these reentry vehicles in test flights of Trident missiles. 82 In a test
conducted in 2002, it demonstrated that the new reentry vehicle could steer toward 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 toward 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. 83 The FY2008 funding
would have supported, among other things, efforts to finalize the guidance and flap system on the
maneuvering body extension of the reentry body, design an interface between the new guidance
system and the missile system flight controls, begin development of a conventional payload that
could fit within the reentry body, and initiate efforts to modify existing facilities so that they
could test the conventional Trident modification (CTM) designs. Congress, however, rejected
these funding requests amid concerns about the rationale for the program and the potential for
misunderstanding if the weapons were used in a conflict.
If it had received the requested funding in FY2008, and proceeded with the expected work plan,
the Navy planned to conduct system development and demonstration activities in FY2008 and
FY2009, and planned to begin production and deployment in FY2010. With this timeline, the
system would have reached its full operational capability by the end of 2012. However, as is
noted below, Congress rejected the Navy’s funding request for FY2008 and restructured the PGS
program.
DOD allocated a portion of the combined funding for the PGS mission to this program area in
FY2009. In documents submitted with its FY2009 budget request, the Navy sought funding for a
Department of Defense. Report of the Defense Science Board Task Force on Future Strategic Strike Forces. February
2004. pp. 5-7.
Grossman, Elaine M., “Pentagon Eyes Bunker-Busting Conventional Ballistic Missile for Subs,” Inside the
Pentagon, June 27, 2002. p. 1. See also, Robert S. Norris and Hans M. Kristensen, “U.S. Nuclear Forces 2005,”
Bulletin of the Atomic Scientists, January/February 2005, pp. 73-75.
81

82 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 T ask Force on Nuclear Capabilities, July 22, 2005.
83 Department of the Navy, Fiscal Year 2008/2009 Budget Estimates, Justification of Estimates, February 2007,

Research, Development, T est, and Evaluation, Navy Budget Activity 4.

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2009 flight experiment “using a Life Extension Test Bed (LETB-2) reentry body on a currently
planned Trident D-5 missile test.”84 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.85 DOD indicated that during
FY2012, it would continue to adapt the LETB reentry bodies as a part of its test-range
development plans.
The Navy also requested, in its FY2009 budget, funding for a reentry body for a conventional
ballistic missiles. This program, known as the Medium Lift Reentry Body, would be too large to
fit on a Trident missile but could carry the warhead on the intermediate-range 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,
and only one or two of the submarines would likely be within range of the targets specified for
attack with conventional ballistic missiles. 86
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, 87 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
84 Elaine M. Grossman, “Controversial Missile Idea Lingers,” Global Security Newswire, March 20, 2008.
85 Elaine M. Grossman, “U.S. Navy Plans August

T est for Conventional T rident-Related T echnology,” Global Security

Newswire, May 21, 2009.
86 Ibid.
87 U.S. Department of Defense, Quadrennial Defense Review Report, February 6, 2006, p. 50.

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seems likely that the Pentagon would have planned to use these missiles only 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. 88 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 Conventional Prompt Strike
The Navy first studied the possible development and deployment of a submarine-launched
intermediate-range ballistic missile (SLIRBM) in the early 2000s. 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. 89 According to the Defense Science Board Task Force, this
missile might have delivered a 2,000-pound payload over a 1,500-mile range, 90 with an accuracy
of less than 5 meters. This would allow the missile to reach its target in less than 15 minutes. 91
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. 92 These missiles could also be deployed on nuclear-capable
Trident submarines, with 2 or 3 missiles deployed in up to 22 of the submarine’s launch tubes, for
a total of 66 missiles per submarine. However, as the concept emerged, it became evident that the
missiles would have been deployed, with perhaps 2 per launch tube, in the four Ohio-class
submarines that have already been converted to carry conventional cruise missiles and other nonnuclear 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. 93 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

88 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.
89 Norris, Robert S. and Hans M. Kristensen, “U.S. Nuclear Forces 2005,” Bulletin of the Atomic Scientists,

January/February 2005, pp. 73-75.
90 A T rident II (D-5) missile can deliver its warheads over a range of 4,000 miles.
91 Report of the Defense Science Board Task Force on Future Strategic Strike Forces, February 2004, pp. 5-12.
92

Koch, Andrew. “U.S. Considers Major Changes to Strategic Weapons,” Jane’s Defence Weekly, September 27, 2003.

93 Grossman, Elaine, M., “ Midrange Missile May be Backup to Modified T rident ,” Global Security Newswire,

September 21, 2007.

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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 toward 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.”94 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. 95
During the Obama Administration, DOD did not specify whether it would deploy a PGS system
on land or at sea. It did, however, leave open the option of deploying the systems at sea, so that it
could pursue technologies that would reduce the cost and risk of the program, as it developed
both the booster and the hypersonic glider technologies, even if they came 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. In addition, the boosters would travel on a flatter trajectory, and would likely have a
different launch profile and a different number of stages, than the existing Trident missiles.
According to General Martin Dempsey, the former Chairman of the Joint Chiefs of Staff, these
differences in technology would likely mitigate the risk of an adversary observing the launch and
concluding, incorrectly, that the United States had launched an attack with a nuclear-armed
missile. 96
DOD has moved forward with the sea-based option for the conventional prompt strike mission. In
its FY2015 budget request, DOD noted that, during FY2013, it began to review a new series of
demonstrations within the Alternate Re-Entry System program area by the Navy’s strategic
systems program. It also stated that it would begin critical design reviews and begin to assemble a
vehicle for a Navy flight test in FY2015. The FY2014 budget documents noted that a flight test of
a Navy variant of a conventional prompt strike system, which could be a reference to the
intermediate-range option deployed on Virginia-class submarines, might occur before the end of
2016, but this was delayed until October 2017, when DOD conducted a successful test of a
booster and glider that could be deployed on a submarine.
The October 30 test, identified as Flight Experiment 1, flew more than 2,000 nautical miles from
Hawaii to the Marshall Islands. Although the flight was launched from land, the test was executed
by the Navy’s Strategic Systems Programs office. The Pentagon estimated that the test cost $160
million, and, while DOD did not identify the specific objectives or results of the test, Vice
Admiral Terry Benedict, head of the Navy's Strategic System Programs office, declared the event
a “success.”97 In addition, in a speech a few days after the test, Admiral Benedict indicated that
94 U.S. Department of Defense, Defense Budget Priorities and Choices, Washington, DC, January 2012, p. 5,

http://archive.defense.gov/news/Defense_Budget_Priorities.pdf.
95 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/.
96 U.S. Department of Defense, Major Budget Decisions Briefing From the Pentagon , Washington, DC, January 26,

2012, http://archive.defense.gov/transcripts/transcript.aspx?transcriptid=4962 .
97 Jason Sherman, “DOD flies experimental hypersonic payload; claims success,” Inside Defense, November 2, 2017.

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the Navy could eventually deploy the conventional strike system on either Ohio class ballistic
missile submarines that have been converted to launch cruise missiles (known as SSGNs) or
Virginia class attack submarines equipped with the Virginia payload module. 98
The DOD budget request for FY2019 indicated that the Navy would conduct a second flight test
by the end of FY2020. The budget request also contained no funds for the OSD-wide account for
Prompt Global Strike Capability Development after FY2019, indicating that “Conventional
Prompt Strike program and funding transfers to the Navy” starting in FY2020. Moreover, funding
for the program has increased significantly, from a request for $278 million in FY2019 to a
request for $1.1 billion in FY2021, and a request for $1.4 billion in FY2022. The Navy’s budget
documents indicate that about $500 million in funding for FY2022 will support Platform
Integration, which will fund engineering efforts associated with deploying the CPS system on
Virginia-class attack submarines. The Navy is also funding efforts to deploy the CPS system on
Zumwalt-class destroyers, a goal it hopes to achieve by FY2025.

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 nonconventional
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),
https://insidedefense.com/inside-army/dod-flies-experimental-hypersonic-payload-claims-success.
98 Jason Sherman and Lee Hudson, “Navy reveals plans to put hypersonic strike weapons on submarines,” Inside
Defense, November 3, 2017, https://insidedefense.com/inside-navy/navy-reveals-plans-put-hypersonic-strike-weaponssubmarines.

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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.”

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. 99

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
99 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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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 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 prejudge 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,

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transferred this funding to a new, integrated account for Prompt Global Strike Research. Congress
also eliminated separate funding of $50 million for other elements of the FALCON program,
rolling them into the new account as well. As is discussed in more detail below, the total funding
for this new account was set at $100 million for FY2008, less than half of the requested funding
for all the programs that were combined in the new account. The Pentagon has objected to this
transfer, noting that the elimination of the specific line items and the overall reduction in funding
would lead to the termination of the FALCON program and the cancellation of several planned
flight tests for the CAV. Although the Pentagon eventually accepted the idea of a combined
program for PGS research, it suggested that the total budget be set at $208 million, an amount
equal to the total proposed for the combined programs, so that each could continue to receive the
required level of investment. 100 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.

100 Department of Defense Budget Appeal, FY2008 Defense Appropriations Bill, October 15, 2007.

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The conference committee adopted the Senate’s approach to combining the funding in a single
account, but, as the Appropriations Committee had done, limited the funding to $100 million
(H.Rept. 110-477). The conference report also required that the Under Secretary of Defense for
Acquisition, Technology, and Logistics submit a plan describing how DOD would obligate the
FY2008 funds (H.Rept. 110-477, §243). This funding profile indicates that Congress did not
reject the Prompt Global Strike concept completely, even though it had not accepted the
Administration’s sense of urgency or its certainty in the need for the CTM program in the near
term.
The House and Senate Appropriations Committees followed the “combined funding” model
established by the SASC. The House Appropriations Committee eliminated the specific funding
for the CTM, directed DOD to create a “prompt global strike program element within the
Research, Development, Test, and Evaluation, Defense-Wide appropriation,” and moved $100
million into this new account to “further the Department’s prompt global strike initiative” without
“limiting the Nation to a single option” at this point in time. Some of these funds could be used to
support research and development on the CTM concept. The committee also mandated that DOD
submit a report “that discusses the technology thrusts and investment objectives and outlines the
allocation of funding towards achieving these objectives.” The Senate Appropriations Committee,
in its version of the bill (H.R. 3222, S.Rept. 110-155) provided $125 million for the Research,
Development, Test and Evaluation, Defense-Wide account for prompt global strike mission. It
noted that these funds should be used “for engineering and development of alternatives to the
conventional TRIDENT missile program.” The final version of the FY2008 appropriations bill
limited the funding to $100 million (P.L. 110-181, H.Rept. 110-477).

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

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/crs%3AR41464. Public record. Not legal advice.