In the vanguard of military innovation, hypersonic and high-energy weapons are poised to redefine the theatre of conflict, offering unparalleled capabilities in both operational and strategic realms. However, the financial burdens associated with their development, production, and deployment are far from trivial. Concurrently, efforts are underway to devise novel defensive systems, either by adapting existing technologies or introducing entirely new frameworks.
Hypersonic missiles, markedly distinct from their ballistic counterparts, eschew the traditional ballistic curve, enabling them to traverse comparatively “low altitudes” and maintain a degree of radar evasion. They possess the capacity for manoeuvre, and can achieve velocities exceeding fifteen times the speed of sound (despite empty weights of up to 4,500 kg). The trade-off comes in the form of substantial heat signatures and structural stress during flight. Moreover, alterations in course generate significant “drag,” which substantially impacts the weapon’s range.
Flight corrections, even minor ones, render their trajectory difficult to predict, complicating the task of pinpointing impact sites or intercepting and neutralising these formidable projectiles. Primarily targeting vital assets such as aircraft carriers, command centres, and crucial infrastructure elements, hypersonic weapons demand attention from military strategists worldwide.
Currently, only Russia, China, and the United States possess the requisite technology to develop and deploy hypersonic armaments. Other nations remain in nascent stages of research or component testing (e.g., engines). Defences against these weapons are similarly scarce; the US alone boasts capabilities in this arena, albeit limited. Experts predict it will take approximately a decade for the US to attain comprehensive proficiency in combating hypersonic threats.
As it stands, the US Armed Forces can detect hypersonic missiles, yet lack the comprehensive ability to neutralise them (at least within the context of anticipated combat scenarios). There remains a pressing need for effective countermeasures and layered defence systems capable of thwarting these missiles during the final stages of their trajectory.
The US Armed Forces rely on satellite systems such as SBIRS (Space-Based Infrared System) and DSP (Defense Support Program) for detecting and tracking missile threats. Paired with radiolocators, these satellites serve as the eyes in the sky, monitoring missile movements within and beyond Earth’s atmosphere. Nonetheless, such measures have proven insufficient.
To address this shortfall, the US Air Force (USAF) has joined forces with the National Reconnaissance Office, the Missile Defense Agency (MDA), industry stakeholders, and research institutions to devise integrated strategies and recommendations for enhancing hypersonic missile detection and tracking capabilities.
In January 2021, the MDA awarded contracts to L3Harris Technologies and Northrop Grumman for developing the HBTSS (Hypersonic and Ballistic Tracking Space Sensor). This next-generation system, designed to integrate with ground-based radars, aims to improve missile tracking capabilities on a global scale. Two prototype satellites are slated for orbital testing as early as 2023.
Funding has also been allocated to develop three Glide Phase Interceptor (GPI) systems. While some countermeasures are available against hypersonic missiles in their ballistic phase or when launched from carriers, the US military anticipates the need for effectors capable of engaging targets during the so-called “glide phase.” This would complete the combat system’s response to emerging threats.
A key objective for the US Armed Forces is transitioning from a regional missile detection and defence system to a globally capable one. To this end, carrier strike groups have been outfitted with Sea-Based Terminal (SBT) systems, designed to bolster the efficacy of the integrated defence system of the future. SBT utilises the capabilities of Aegis Baseline 9C, including SPY-1 radars and SM-6 missiles. In addition, specialised aircraft such as reconnaissance, early warning, and command and combat planes (including the cutting-edge F-35) will serve as crucial support elements.
In the realm of hypersonic capabilities, recent developments have enabled the detection and tracking of hypersonic weapons. Yet, there remains insufficient time for an effective countermeasure. Each trajectory alteration necessitates significant recalculations in order to neutralise an adversarial missile.
As hypersonic missiles have the capacity to modify altitude or direction, doing so often results in diminished speed and range. Even minor adjustments can have considerable implications for these factors. Additionally, the material composition of these advanced projectiles is crucial, as they must withstand extreme temperatures and pressure distributions. Slight hull deviations may generate substantial forces, producing shock waves and even the separation of control surfaces.
Consequently, manoeuvres typically occur mid-flight, with an altitude reduction to approximately 50 kilometres. Greater distances can be traversed using supplementary lifting forces. At these lower altitudes, increased lift and drag result from the denser atmosphere and gravitational effects. For a supersonic vehicle gliding at Mach 15 equivalence, a 30-degree turn could necessitate up to seven minutes of correction, reducing its range by 2.5-3 kilometres if at an altitude of 40 kilometres. Although a quicker manoeuvre is feasible, it would curtail the vehicle’s range by an estimated 25%.
Future enhancements in manoeuvrability whilst preserving requisite ranges may be afforded by next-generation supersonic ramjet engines with advanced supersonic combustors. Such engines could accelerate objects to hypersonic speeds exceeding Mach 10. In a proposed iteration, this system would harness ambient oxygen as an oxidant, confining its usage to suborbital flights. This technology presents a compelling alternative to conventional rocket propulsion, attracting the interest of not only military entities, but also private companies such as SpaceX, due to its lower costs and heightened operational safety.
The principal challenge posed by hypersonic missiles lies in their distinct flight parameters when compared with vehicles traversing a ballistic trajectory. Hypersonic missiles operate at altitudes ranging from 20 to 60 kilometres, soaring higher than combat and specialised aircraft, yet lower than intercontinental missiles or other extraterrestrial objects. Consequently, these altitudes render hypersonic missiles too high for atmospheric anti-missile systems such as the Patriot, and too low for non-atmospheric systems like the SM-3. At these elevations, counter-missile aerodynamic rudders lose efficacy, and thrusters remain inefficient. Rapid manoeuvring swiftly depletes fuel reserves, thereby limiting range.
Terminal defence remains the sole recourse, yet the speed and non-ballistic trajectories of hypersonic missiles afford a relatively narrow window of opportunity, permitting a single attempt due to the absence of time for coordinating additional attacks. For instance, SBIRS satellites can detect rocket launches and identify them based on the heat signature generated. Although theoretically capable of tracking hypersonic weapons, doing so would necessitate constant monitoring and precise positioning, a near-impossible feat that would require the deployment of an entire satellite constellation potentially needed for other tasks.
Millennium Space Systems proposes a solution involving a constellation of satellites deployed in MEO and LEO orbits, although situating satellites in these regions, between 2,000 and 35,786 kilometres and up to 2,000 kilometres above Earth, presents its own challenges. In the case of GEO, satellites orbit Earth synchronously with its rotation, offering constant observation of the same point on the planet. However, the object’s accelerated motion induces relative movement between the satellite and the apparent point on Earth.
While GEO allows for global coverage with a smaller satellite fleet, it sacrifices accuracy due to distance. LEO provides enhanced detectability albeit with a limited field of view, necessitating a larger satellite constellation. MEO offers a balanced approach. In summary, each orbit possesses unique advantages and disadvantages.
Consequently, experts contend that a new constellation system should place cooperating satellites in various orbits, utilising a layered system architecture. Moreover, they recommend increased autonomy in detecting, analysing, and transmitting data collected by satellites, as well as real-time data processing by the satellite itself rather than Earth-based teams.
Addressing the challenges posed by hypersonic weapons necessitates not only effective targeting and tracking but also adequate response time. Neutralisation strategies may include traditional interception, electronic warfare (EW) systems, or cyberspace measures, with an optimal approach employing these methods simultaneously.
According to American experts, if hypersonic missiles were to travel at speeds below Mach 6, the latest generation Patriot system could potentially counter them. Nevertheless, as speeds increase, the need for efficient data processing systems and swift effectors capable of outpacing the missile becomes paramount. In this context, detection and tracking systems play a critical role, as the speed at which they identify potential targets greatly influences the neutralisation process.
Hence, the construction of a new, multi-layered sensor system for detection and tracking is essential. The first component would comprise satellites monitoring the launch, cruise, and transfer phases until ground-based radars assume responsibility for the target. This acquired data would then be relayed to a new gliding phase interception system that could be deployed on warships, such as destroyers or cruisers. Missiles like the SM-6 have the potential to neutralise hypersonic missiles, provided they obtain sufficient data on the missile’s tactical and technical parameters and in-flight manoeuvrability. Notably, direct impact with the target is unnecessary, as detonation in close proximity suffices. However, this demands further modification of the warheads.
In response to such threats, some American companies are adapting their offerings. For instance, Lockheed Martin is currently working on modifying its THAAD-ER system to combat hypersonic systems.
The American Advanced Research Projects Agency (DARPA) oversees the development of the Glide Breaker programme, awarded to Northrop Grumman, which aims to create interceptors capable of destroying hypersonic missiles and other high-maneuvering targets in the upper atmosphere.
Some experts argue that hypersonic weapons are more effective against strategic missile defence systems than operational-tactical ones. As such, medium-range (up to 3,500 km) and intermediate-range (up to 5,500 km) systems may not revolutionise the field of combat. According to the American Missile Defense Agency (MDA), laser systems, even those of low power currently under development in the United States, could be the most effective means of countering such threats.
In summary, the demands of developing, constructing, and utilising hypersonic systems necessitate countries possessing significant military, technological, and economic potential. Advanced technologies and new-generation propulsion systems are required, as well as effective positioning, reconnaissance, command, and radio-electronic warfare capabilities, which remain out of reach for most nations.
Defending against hypersonic weapons is a challenge that each country must confront. At present, however, no nation possesses full capabilities in this regard. The United States is closest to achieving this goal, but considerable time is needed to develop a fully effective system for detecting, tracking, and combating hypersonic missiles.
A crucial component of this system is the reconnaissance network, comprising elements in space, air, land, and sea. An efficient system for automating data collection and analysis will support it. In terms of combat effectors, two paths have been chosen: modernising existing missile sets or creating entirely new ones. The future may also see the deployment of high-energy weapons or electronic warfare systems.