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 HSMWs.
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.
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 assets.
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
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.
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 vehicle 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 altitudes.
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 maneuverable” 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 urgency. 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.
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/hrpt537/CRPT-114hrpt537.pdf).
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