Quoted section below was excerpted from:

An appendix including biographical sketches of committee members is available at the above link.

A Threat to America’s Global Vigilance, Reach, and Power
Unclassified Summary

Committee on Future Air Force Needs for Defense Against
High-Speed Weapon Systems
Air Force Studies Board
Division on Engineering and Physical Sciences

A Report of
The National Academies of
Sciences - Engineering - Medicine


In February 1949, a research team led by rocketry pioneer Frank Malina
launched a two-stage missile, composed of a captured German V-2 topped by a
WAC Corporal sounding rocket, into the skies above the White Sands Proving
Ground in New Mexico. On this fifth launch attempt under a project named
that WAC Corporal rocket became the first manmade propelled object
to fly at hypersonic speeds, in excess of five times the speed of sound. That small
rocket ushered in the age of hypersonic flight.
By the late 1950s, the United States had established itself as the undisputed
leader in high-speed flight. With programs such as the X-15 Rocketplane, the
and PRIME vehicles of the 1960s, and more recently the X-43, HIFiRE, and
X-51, in the classroom and in wind tunnels, U.S. researchers have consistently led
the world in advancing the science and art of high-speed flight. The expertise that
informed those programs pioneered the development of new propulsion systems,
aerodynamic concepts, control methodologies, and advanced high-temperature
materials. Hard-won knowledge of the hypersonic flight corridor led directly to the
successful design of manned and unmanned space vehicles, as well as the warheads
of the U.S. nuclear arsenal.
Now, six-and-a-half decades after Project Bumper, the U.S. lead in the technologies
of high-speed flight is in question, particularly as it pertains to military
applications. Several countries around the world have been quite busy establishing
their own capabilities, in many cases building directly on work gleaned from
the United States. These countries have recognized the military potential of speed
and see it as a promising counter to U.S. capabilities. Their investments have been
significant, their advancements notable, and their accomplishments in some
cases startling. These countries have made no secret of the fact of their interest in
nor of their intentions. They have taken advantage of data and lessons
learned from the United States and have been helped by the start-stop approach to
technology development (including canceling programs even after major successes)
and inefficiencies
in the U.S. acquisition processes. As a result, the Committee on
Future Air Force Needs for Defense Against High-Speed Weapon Systems has concluded
that the United States may be facing a threat from a new class of weapons
that will effectively combine speed, maneuverability, and altitude in ways that could
challenge this nation’s tenets of global vigilance, reach, and power.
This National Academies of Sciences, Engineering, and Medicine report was
commissioned by the U.S. Air Force (USAF) to address the question of what, if any,
response would be possible to defend against the threat of high-speed weapons.
The committee quickly realized that while responding to high speed is challenging
in its own right, the combination of high speed and the unpredictability of high
maneuverability poses an even greater hurdle. A lifting-body hypersonic weapon,
operating at high altitude but in the sensible atmosphere, could use aerodynamic
forces to make its trajectory difficult to predict and even more difficult to interdict.
As a result, this report highlights some of the challenges to providing a defensive
capability against the combination of speed and maneuverability.
When this study began, the committee hoped to identify a class of technology,
or suite of technologies, perhaps even currently in development, for employment
against high-speed maneuvering threats. The committee saw many concepts and
heard about many different possible approaches, but in the end it concluded that
there are no “silver bullets.” Stopping a maneuvering hypersonic weapon will be
difficult, which is precisely why potential adversaries may be pursuing such systems.
More importantly, the committee found that while methods might be developed to
defend against one or two incoming threats, traditional approaches in employing
defensive measures may be less effective against multiple high-speed maneuvering
weapons. As such, the reader of this report will find relatively few concrete recommendations
for specific technologies to pursue; rather, the report offers the observation
that sustained research and development is needed that considers a range
of approaches, and those must be pursued in a coordinated and timely manner.
The committee’s charter was to focus on defense—how the United States could
respond when the pointy end is heading toward us. And indeed, the bulk of our
analysis has explored defense from both a technology and a roles-and-missions
standpoint. But the report also ventures into discussions of developing offensive
capabilities as well, for both a counter and a defensive response. The committee
considers this topic to be within the study’s statement of task, for it was made clear
in several thoughtful briefings and associated discussions that the best defense,
perhaps the only defense, against an opponent’s high-speed maneuvering weapon may
be another high-speed maneuvering weapon. Offense and defense are two sides of
the same coin; as in the days of the Cold War, the only reliable deterrent to the use
of a hypersonic weapon may in fact be the threat of a corresponding hypersonic
countermeasure that might hold at risk the very sites from which the adversaries’
hypersonic strike would originate. To better understand the potential operational
capabilities and technical characteristics of such weapons, as well as their potential
vulnerabilities, it will be important for the United States to make its own timely
investments in this area. To this end, the United States’ relatively leisurely pace of
disjointed hypersonics technology developments, the lack of diversity in concepts,
and the absence of a clear acquisition pathway appear to stand in stark contrast
to potential adversaries’ feverish pace of research and development and test and
evaluation, as well as their broadly cast net of technology options.
Although it was the USAF that asked the National Academies to examine this
subject, this report touches on multiple services and organizations within the
of Defense (DoD). In the committee’s view, a future commander may
not have the time to debate whether an incoming threat should be addressed by
the Army or the Air Force, nor the leisure to deliberate on whether an incoming
warhead is technically a ballistic missile or a hypersonic cruise missile. Rather, the
organizational roles and missions may need to make the resulting response seamless.
To that end, and as this report makes clear, the solution to the high-speed
maneuvering weapon threat may depend on a coordinated DoD-wide effort. The
committee leaves the specific details of that coordination to others, but offers the
view within these pages that potential adversaries are already designing systems that
exploit both organizational disconnects and current defensive technical limitations
within the United States.
The committee is convinced that the USAF has a critical role to play in developing
and employing the possible options to address the challenge of high-speed
maneuvering weapons, as well as in providing the intellectual leadership for the
DoD and the nation in this field.
Mark J. Lewis, Chair
Committee on Future Air Force Needs for
Defense Against High-Speed Weapon Systems

Statement of Task and Study Approach

The Air Force Studies Board (AFSB) of the National Academies of Sciences,
Engineering, and Medicine was asked by the Assistant Secretary of the Air Force for
Science, Technology and Engineering to assess the threat of high-speed weapons
and recommendations to counter the threat. The National Academies approved
the original statement of task for this study in April 2015 and its revision in January
2016 and appointed the Committee on Future Air Force Needs for Defense
Against High-Speed Weapon Systems in October 2015.1 The committee was asked
to address
the following topics:
1. Review the current and evolving threats and the current and planned U.S.
efforts and capabilities to counter these threats.
2. Identify current gaps and future opportunities where the USAF could
provide significant contribution to the U.S. effort to counter high-speed
3. Recommend actions the USAF could take in terms of materiel, nonmateriel,
and technology development to address the identified opportunities and gaps
in U.S. efforts to address these threats.
To address these topics, the committee held four data-gathering meetings,
which included face-to-face and telephone interviews, from December 2015 to
April 2016 to review, independently research the topic, conduct interviews with
experts, identify key findings, and develop recommendations. A fifth meeting was
held in May 2016 for the committee to write a classified report of its findings
and recommendations. Throughout the course of the study, the committee met
with the Air Force Air Combat Command (ACC), Air Force Research Laboratory
(AFRL), National Air and Space Intelligence Center (NASIC), Missile Defense
Agency (MDA), U.S. State Department, U.S. Pacific Command (PACOM), U.S.
Northern Command (NORTHCOM), Defense Advanced Research Projects Agency
(DARPA), Air University, Office of the Secretary of Defense (OSD), Naval Research
Laboratory (NRL), Sandia National Laboratories, and RAND.
The committee received briefings and reviewed data up to the TS/SCI level in
responding to the study statement of task and made every attempt to provide
a balanced and fair assessment using the data provided.

The following is an unclassified executive summary report.

Executive Summary

The following is a summary report that highlights a potential national security
threat. The People’s Republic of China and the Russian Federation are already
flight-testing high-speed maneuvering weapons (HSMWs) that may endanger both
forward-deployed U.S. forces and even the continental United States itself. These
weapons appear to operate in regimes of speed and altitude, with maneuverability
that could frustrate existing missile defense constructs and weapon capabilities.
This new class of HSMWs may in many cases operate in the seams of the
U.S. national security organizational structure, creating challenges to effective
and timely command and control should they be employed against U.S. forces or
the United States itself, as described in Box 1. Put another way, while operational
doctrine and command structures adequately address traditional atmospheric air
attack or exoatmospheric ballistic missile attack, existing doctrine and organizational
structure may not be adequate to address the cross-domain threat posed by
It may seem reasonable to dismiss this threat as overblown or nonexistent, akin
to a 21st-century equivalent to the infamous Eisenhower-era “Missile Gap,” in part
because it has taken decades for this threat to develop. Likewise, it is possible to suggest
that a high-speed maneuvering weapon may be defeated by some “
silver bullet”
solution waiting in the wings. It may even be argued that such systems will never
reach operational maturity, given the long and contentious history of hypersonic
development and the overpromise that has often characterized the field. However,
the value of extreme speed coupled with maneuverability and altitude constitutes
a potential threat to U.S. capabilities that should not be discounted or ignored.

Gaps and Seams
Gaps and seams in organizational and institutional defense can be created through structures,
doctrines, and geographic and historical responsibilities and cultures.
The United States has an established defense architecture for ballistic missiles. The Missile
Defense Agency has a fully structured and established military structure for identifying and
responding to ballistic launches—the U.S. Strategic Command. The Department of Defense has
integrated combatant commands for responding to threats and managing crises in geographic
regions developing and potentially launching intercontinental ballistic missiles. The Intelligence
Community has global coverage divided into regional functional and technology areas. All of
these agencies and organizations are part of a layered defense architecture for ballistic missiles:
detection systems, communications networks, sensors, command and control battle management
systems, and integrated battle plans and weapons for response.
In contrast, the committee believes there is no such architecture for high-speed maneuvering
weapon (HSMW) defense. HSMWs cross all of these boundaries. They are operational
in all military domains: air, sea, land, space, and cyber. They exploit geographic areas
and atmospheric space that may not be covered by sensors or detectors. They cross all
Combatant Command Area of Responsibility boundaries: U.S. Pacific Command (PACOM),
U.S. European Command (EUCOM), U.S. Central Command (CENTCOM), U.S. Northern
Command (NORTHCOM),
U.S. Strategic Command (STRATCOM), and U.S. Cyber Command
HSMWs have the characteristics of both air and space vehicles and can be
either strategic (nuclear) or tactical (conventional) weapons.

In the wake of two world wars, the United States emerged as the world’s single
most powerful nation. Crucial to U.S. success in the 40-plus years of the Cold War
was creating the scientific and technological capability to enable the United States
to reach and project power around the globe, bolstering allies, supporting friends,
and confronting aggressors. A central and defining aspect of that capability has
been the U.S. integrated land-air-and-sea-based power, empowered by space-based
The nature of the U.S. air and space power advantage is captured in the Air
Force’s recognition of “Global Vigilance, Reach, and Power” as the core contributions
that the Service brings to U.S. national security. Through the awareness, access,
and combat force made possible by U.S. Air Force (USAF) systems, the United
States has maintained a robust global presence sustained by air and sea lines of
communication and overseen by a rapidly responsive command and control infrastructure.
The United States relies on this presence to exercise policy options that
support its friends and allies, defend its own national security interests, conduct
humanitarian relief, and promote other initiatives.
At the present time, the USAF—and Joint Forces more broadly—is facing an
emerging class of threats that could severely challenge global vigilance, constrain
global presence, and impede global power, against which current defensive capabilities
are inadequate: HSMWs. High-speed maneuvering weapons could pose a
challenge to all three core elements of the USAF—and be an impediment to the
application of global power in key regions of the planet.
Both the People’s Republic of China and the Russian Federation have flown
examples of this class of weapon, and other countries have shown interest in many
of the underlying technologies for hypersonic flight. As illustrated in Figure 1,
HSMWs can fly at high-supersonic (Mach ≥ 3.5)1 or even hypersonic (M ≥ 5.0)
velocities, maneuver both for deceptive/defensive purposes and to increase their
range of attack options, and operate both within and outside the atmosphere,
following flight paths that place them beyond conventional ballistic and cruise
missile defenses.
Hypersonic speeds can be achieved through two known approaches. The first
is a ballistic launch to high speed, typically on a rocket booster, that enables a
subsequent unpowered glide trajectory; a vehicle in this class is referred to as a
hypersonic glide vehicle (HGV). The second approach is an air launch–enabled
trajectory of a vehicle propelled by its own rocket, ramjet, or scramjet; such a
would generally be a long-range hypersonic cruise missile (HCM). There
are of course hybrid approaches; for example, ballistic boosted vehicles may also be
internally powered and thus be considered HCMs. Similarly, a boost-glide vehicle
could be scaled down and air launched, resulting in a tactical HGV.
In addition to flying at high speed through most of their trajectories, both
categories of HSMWs will also likely impact their targets at velocities in the high-supersonic
(Mach ≈ 3.0-4.0) range. They could maintain significant maneuverability
with precision, and thus be capable of engaging fixed or slow-moving targets, such
as a runway, command and control facility, or seagoing vessel. Both categories of
high-speed weapons may be capable of carrying conventional or nuclear warheads,
thereby complicating strategic intent and posture as well as operational identification,
response, and engagement. Both types of systems operate below the classical
ballistic missile trajectory and above typical low-speed cruise missile operating
The question may be asked, So what? The United States has successfully
confronted evolutionary threats before; why is this any different? The answer to
this question is the following: HSMWs are not simply evolutionary threats. They
are not merely faster or longer-range cruise missiles. Nor are they simply “more
reentry vehicles or depressed trajectory ballistic missiles. This is
no mere tweaking of an existing threat. Rather, HSMWs can combine speed and
maneuverability between the air and space regimes to produce significant new
offensive capability that could pose a complex defensive challenge.
The technical challenges posed by HSMWs are compounded. The committee
could find no formal strategic operational concept or organizational sense of
Further, the committee believes there is a lack of leadership coordination
to provide efficiency and direction for the development of possible countermeasures
and defensive solutions across the Department of Defense (DoD). If it
is to be effective in providing integrated mission direction, that leadership will need
to come from a high-level mission-accountable organization within DoD that can
address materiel and nonmateriel solutions—to include budget authority—across
military services, agencies, and the research community. This organization must
have responsibility for development, testing, deployment, integration, and sensors,
as well as the battle management command control and communications systems
(BMC3) for HSMW. Importantly, to be successful, it will need to have strong ties
to the operational community. Considering the nature of the potential threat posed
by HSMW systems, the identification of a leadership structure to pursue the actions
recommended in this report deserves attention.
As just one example of the degree of integration required, the intrinsic nature
of HSMW flight profiles and employment may greatly compress decision and response
timelines, which in turn requires any useful countermeasures to be deployed
almost immediately. Providing staged responses and avoiding escalations to maximum
response will necessitate heuristic processes in the short time window of the
HSMW attack. Development of advanced systems may therefore be a necessary element
of the command and control doctrine and decision process. The responsible
organization will need to take such considerations into account.
A major challenge to organizational leadership is that the development of
countermeasures to HSMW systems may fall outside of current mission responsibilities.
Defending against HSMWs, while clearly and unequivocally recognized as
important by Missile Defense Agency (MDA) leadership, may not be fully addressed
because HSMWs are not considered ballistic missiles, even though certain phases
of launch and flight can have characteristics similar to those of a ballistic missile.
Furthermore, MDA’s focus has been on providing an active defense capability with
few resources directed toward preemptive or counterstrike options. Fortunately,
MDA leadership has been very forward-leaning in addressing this situation, and
there have been recent positive developments.2
Although a detailed analysis of proliferation issues is beyond the scope of this
report, it is only logical that pursuing solutions in an integrated manner would
provide policy developers a sense of direction, as well as offer the diplomatic
community an informed base for integration into international regimes for arms
control and deterrence. Further, a visible response to impending threats will demonstrate
resolve to both our potential competitors and our own military personnel.
In summary, the ability of the United States to sustain its presence around
the world and leverage its global reach is dependent on both U.S. Navy and USAF
forward deployment. At a military operational level, HSMWs may impede operations,
global vigilance, maintenance, and supporting logistics. At a national strategic
level, HSMWs could hold at risk the fundamental U.S. construct of global reach
and presence.

1 Since speed of sound varies with altitude (being approximately 1,100 ft./sec. at sea level and
675 ft./sec. at 100,000 feet), the most common measure of supersonic and hypersonic speed is Mach
number, named after the Austrian physicist Ernst Mach. Mach number (M) is the velocity of an airplane
or missile divided by the speed of sound at the altitude at which it is flying. Mach = 1.0 is the
speed of sound, the demarcation between subsonic and supersonic flight; Mach 5 (roughly 1 mile
per second) is traditionally considered the lower boundary of hypersonic flight, which extends to
orbital velocity up the Mach scale.

2 Section 1657 of the National Defense Authorization Act for Fiscal Year 2017 Report of the Committee
on Armed Services, House of Representatives, on H.R. 4909 directed the Missile Defense
Agency to establish a program of record to develop and field a defensive system to defeat hypersonic
boost-glide and maneuvering ballistic missiles
(May 4, 2016, https://www.congress.gov/114/crpt/hr...114hrpt537.pdf).