Military & Aerospace

Countering Hypersonics
Star Rating Loader Please wait...
Issue Net Edition | Date : 18 Jan , 2024

In 2023, several reports appeared in the media after the supply of Patriot missiles to Ukraine claiming repeated shooting down of Russian Kinzhal hypersonic missiles by Ukraine using the Patriots. It led to an interesting war of words between Russia and Ukraine as Russian Defence Minister Sergei Shoigu dismissed the claims and instead said that a Kinzhal had destroyed a U.S.-built Patriot surface-to-air missile defence system while Ukraine stood by its claims. Shoigu further made light of Ukraine as he said that the number of claimed Ukrainian missile intercepts in general is “three times greater than the number we launch. And they get the type of missiles wrong all the time. That’s why they don’t hit them”.

…it is believed that it was not feasible for the existing air defence systems to intercept a hypersonic missile.

The first claim by Ukraine, of having shot down a Kinzhal, was made in May 2023, using a patriot missile. The claim was confirmed by US military, but it was not verified whether the Russian missile was flying at hypersonic speed at the time. This was followed by another claim that Ukraine had struck an entire volley of multiple Kinzhal missiles. The claim was apparently made to demonstrate the effectiveness of Ukraine’s newly deployed Western air defences. If true, it would be a major achievement for the air defences as it is believed that it was not feasible for the existing air defence systems to intercept a hypersonic missile. Meanwhile, a report in Brookings claimed that Kinzhal missiles were overhyped and were in fact only supersonic missiles, not hypersonic.

Before discussing the feasibility and means of countering hypersonics, it is important to first understand what hypersonic missiles are and how do they differ from other missile systems. The word hypersonic is an American invention, a rough translation from the German for high supersonic. It was first used by Nazi Germany to describe a boost glide weapon during the 1940s.

A hypersonic weapon is a weapon capable of travelling at hypersonic speed, defined as between 5 and 25 times the speed of sound or about 1 to 5 miles per second (1.6 to 8.0 km/s). They are highly maneuverable and can change course during flight. The requirements for achieving lift and minimizing drag and heating during flight force hypersonic systems to operate in what is typically called the near space regime, which is between 20 kilometers and 60 kilometers. The hypersonic usually flies at around 20 kilometers.

Weapon Characteristics and Commonalities (Click to enlarge)

There are two main categories of hypersonic weapons:

•  Hypersonic glide vehicles: they are launched from a rocket. The glide vehicle then separates from the rocket and thereafter manoeuvre and glide through the atmosphere at around Mach 5 speed after an initial ballistic launch phase, and

•  Hypersonic cruise missiles: cruise missiles which use air-breathing engines such as scramjets to reach high speeds.

•  Hypersonic aero-ballistic system: it is released from an aircraft, accelerated to hypersonic speed using a rocket and then follows a ballistic, meaning unpowered, trajectory. The system Russian forces have been using to attack Ukraine, the Kinzhal, is an aero-ballistic missile. The technology has been around since about 1980.

The other types of hypersonics include the following:

•  Hypersonic aircraft using air-breathing engines such as scramjets to reach high speeds.

•  Guns which fire cannon-launched guided projectiles. These may be developments of traditional artillery or novel technologies such as railguns.

•  Ballistic missiles traveling at high speeds during its atmospheric reentry.

•  Hypersonic air-to-air missile (AAM): an AAM which use air-breathing engines such as scramjet to intercept air targets (such as Vympel R-37)

Sources: Congressional Research Service/MDAA/UCS/Statfor/KCNA/FT *Supersonic Combustion Ramjetes (Click to enlarge)

What sets the hypersonic weapons apart from the ballistic missiles is maneuverability. While the ballistic missiles can also travel at hypersonic speeds (of at least Mach 5), they have set trajectories and limited maneuverability unlike the highly maneuverable hypersonics. The important aspect to note thus is not the speed but that the hypersonic missiles represent a broader trend of moving away from purely ballistic trajectories towards lower, more maneuverable, and less predictable flight.

Existing Hypersonics

While the hypersonics are being developed by several countries, only two nations have operationalized them- Russia and China. Russia has been pursuing hypersonic weapon technology since the 1980s and became the first nation to deploy hypersonic weapons in combat when it launched at least one such missile against a target in Ukraine in May 2022 to target what they said was an underground weapons storage site in the west of the country.

The hypersonic missile used in Ukraine is the Kinzhal, which is launched from a combat aircraft. Russia also has a hypersonic glide vehicle, the Avangard, and is developing the Tsirkon, a ship-launched hypersonic cruise missile. Avangard reportedly carries a nuclear warhead and is claimed to have been deployed in service since December 2019. The other systems include the the ship-launched Zircon hypersonic missile, with a top speed of Mach 8 and a range of 1,000 kilometers and an air-launched hypersonic missile (the Kh-95) while Russia also plans to place a hypersonic glide vehicle on its Sarmat intercontinental ballistic missile.

Chinee DF-17 Hypersonic Glide Vehicle

While Russia is the first country to have used a hypersonic missile in combat, it is China that is assessed to have the world’s leading hypersonic arsenal. To develop and test hypersonics, China operates two research sites for hypersonic weapons and its operational hypersonic arsenal includes the DF-17, a medium-range ballistic missile with a hypersonic glide vehicle that has a range of 1,600 kilometers and the DF-41 intercontinental ballistic missile, which also carries a hypersonic glide vehicle. The other systems include the DF-ZF hypersonic glide vehicle, with a range of close to 2,000 kilometers, and the Starry Sky-2, a nuclear capable hypersonic prototype.

On the other hand, the United States is still in the process of developing of hypersonic weapons with the weapons systems still in the development or testing phase, though at least one system is expected to reach early operational capability this year. U.S. hypersonic weapons are expected to be armed with conventional warheads.

Hypersonic weapons are fast and maneuverable but if high-speed maneuverability is their key feature and attribute, it is also a potential weakness.

North Korea claims to have successfully test-fired two hypersonic missiles so far this year — one on January 5, and the latest on January 11, according to state-run Korea Central News Agency. However, U.S. officials have so far not confirmed the claims and have described them only as ballistic missile tests. The other countries developing hypersonic weapons technology include Australia, India, France, Germany and Japan. Also, Iran, Israel and South Korea are reported to have done what has been described as “foundational research” on hypersonic weapons.

Vulnerabilities

Hypersonic weapons are fast and maneuverable but if high-speed maneuverability is their key feature and attribute, it is also a potential weakness. The heat and drag imposes limits on their ability to maneuver and they expend energy in doing so.

The Challenges in Countering Hypersonics

Understanding the speed of hypersonics in a simplistic manner is the best way to explain the challenge in countering them. A vehicle that’s traveling at hypersonic speeds travels more than three kilometres every two seconds. So, every second it takes for the missile defence to identify, every second it takes to track, every second it takes to identify and classify it as a threat to be engaged, the vehicle has travelled more than a kilometre and half. One minute at 90 kilometres, and in two minutes, 180kilometres, at least, at a minimum. That is the challenge, in simple terms, posed by hypersonics by their speed but that is not the only issue.

The main challenge is the inability of existing sensors’ to detect the hypersonics due to their high speed combined with unpredictable maneuvers. Because their flight paths can change as they travel, they pose a real challenge due to their maneuverability all along their trajectory and defending against these missiles requires tracking them throughout their flight. Besides this, the limits of Earth’s geometry mean that new classes of hypersonic missiles could fly under the radar horizons of ground- and maritime-based radars. The ability to maneuver throughout their course of flight also make it difficult to determine their intended target unlike in case of ballistic missiles with their predictable trajectory.

Another factor that needs consideration is that they operate in a different region of the atmosphere from other existing threats. The new hypersonic weapons fly much higher than slower subsonic missiles but much lower than intercontinental ballistic missiles. This makes it difficult for the existing missile defence radar networks of to detect and track them

Source: CSIS Missile Defense Project
A screenshot from a new report by the Center for Strategic & International Studies shows how ground-based radars may not be able to track hypersonic weapons.

The speed and maneuverability are not the only reasons for difficulty in detecting and tracking them. One of the methods used to detect missiles, including hypersonics, by space based sensors is the use of infrared sensors to detect thermal signatures of missiles from space. While it works fine to detect the large, hot exhaust plumes of a ballistic missile launch, the infrared signatures of hypersonic weapons diminish beyond the boost phase making it difficult to be picked up by the IR sensors. As a rough guide, hypersonic weapons are 10 to 20 times dimmer than most weapons that are generally tracked with existing architecture.

Another factor that adds to difficulty of detecting a hypersonic missile is its size – hypersonics are small that it may not be easily found among the pixels on a sensor’s focal plane array. A sensor with a wider field of view may cover a larger portion of the Earth’s surface, but it may lack the fidelity needed to track a missile and provide fire control.

Russian Ministry of Defence graphic showing how hypersonic weapons such as Avangard (right) pass under ballistic missile defences(left).

As hypersonic weapons are extremely difficult to detect and counter given the weapons’ speed and maneuverability, low flight paths and unpredictable trajectories, the existing sensor architecture and command and control can only just about track hypersonic threats to support warnings and domain awareness but nothing beyond that. While the more advanced air defence systems claim to have the capability to engage some hypersonic threats in the latter part of the missile’s flight path, called the terminal phase, the ability to engage the missile in mid-course is non-existent.

…given the speed and manoeuvre capabilities of hypersonic missiles, a workable option is a space-based tracking and targeting capability to track them from space.

The Options

United States initiated its hypersonic defence programme in 2018 with focus on developing and harnessing select technologies for sensors and interceptors. With the basic challenge being of detecting the hypersonics in time, given the speed and manoeuvre capabilities of hypersonic missiles, a workable option is a space-based tracking and targeting capability to track them from space.

A study claims that an unique phenomena at hypersonic speeds (about 3,800 miles per hour or faster) could also make these weapons easier to detect and track for certain sensors. According to Masao Dahlgren, a Missile Defense Project fellow at the Center for Strategic & International Studies, novel wavelengths of light are released as a result of chemical reaction caused by the wakes and the plumes left by hypersonic weapons and the ripping off of the vehicle surface by the plasma that surrounds it. Tools for detecting those wavelengths could be used by space-based sensors for missile warning (detecting missile launches), tracking (tracking missile trajectories), and fire control (guiding interceptors to a threat). 

As part of the space based sensors network, the United States Space Development Agency approved plans to build and deploy to build 16 satellites for detecting and tracking hypersonic missiles in low-Earth orbit (LEO). In addition, six missile warning and tracking satellites will occupy medium-Earth orbit (MEO) starting in late 2026. Before the end of the decade, the United States aims at deploying a network of more than 90 missile warning and tracking satellites in LEO and 27 in MEO.

To cater for the blind spots in sensors using existing technologies, one option is to explore new technologies for spotting the unique signatures of hypersonic missiles. These could include hyperspectral or ultraviolet sensors capable of spotting the “wake of ions, gases, particles, and other chemical by-products” released when the surface of a hypersonic object reacts with high-temperature airflow. Radar could be another alternative sensor while it may even be possible to intercept radio emissions from data-linked missiles and employing improved Infrared sensors to take higher-resolution images for picking up hypersonics in mid-course. The better option, is of course, to employ a diverse mix of sensors to ensure that all bases are covered.

The other option for interception of hypersonics is the use of directed energy weapons using high-power microwaves and laser weapons.

For the interceptor, the idea was to have a glide phase interceptor for which the options include the SM-3 or a derivative of that, and the Terminal High Altitude Area Defence (THAAD, also a derivative of that, and a Sea-Based Terminal program with the SM-6 adapted for this role. Meanwhile, Unites States’ Defence Advanced Research Projects Agency (DARPA) is undertaking a Glide Breaker program with Boeing as the lead agency. According to DARPA, the glide breaker programme aims to “develop and demonstrate a technology that is critical for enabling an advanced interceptor capable of engaging manoeuvring hypersonic threats in the upper atmosphere.”

The glide breaker is expected to enable the United States to intercept Hypersonic Glide Vehicles (HGVs), forming a perfect ‘defence by denial’ deterrent with the ongoing four-year development phase of the Glide Breaker program will determine how factors like hypersonic airflow and firing jet thrusters to guide the vehicle affect system performance at extreme speed and altitude in a representative digital environment, before the next phase to develop the interceptor is undertaken.

The other option for interception of hypersonics is the use of directed energy weapons using high-power microwaves and laser weapons. These are however being studied as long term options.

Understanding Ukraine’s claims

As mentioned earlier, Ukraine has repeatedly made claims of having shot down a number of Kinzhal missiles. Several reports claimed that Russia had overhyped Kinzhal’s capabilities and that it was just a supersonic ballistic missile albeit an air -launched one. The Western media put out several reports indicating that Russian hypersonic missiles do not yet pose the dire threat and there was no reason to believe the hypersonoic hype.

An article in Brookings Institution even claimed that “existing missile defenses can already intercept missiles traveling far faster than HGV’s or Hypersonic Cruise Missile (HCMs), and could be adapted to intercept hypersonic missiles as well.” It went on to further claim that the U.S. Aegis sea-based terminal defense system already had a nascent capability to counter hypersonics.

These claims about the capability to shoot down hypersonics flies in the face of known facts and needs to be called out. A simple method to determine the actualities is to look at the details of Kinzhlas and the reason why they or any other hypersonic cannot be intercepted by existing air defence systems.

The missile then follows an aero-ballistic flight profile as it flies at the stratosphere boundary to minimize air resistance and eventually reaches Mach 10 speed.

Kinzhal Missile and the Russian Hypersonics

Of all the hypersonioc missiles, Kinzhals have been the only weapons system that has been operationally used- during the ongoing ‘Special Military Operations’ against Ukraine. It is an important part of the Russian “strategy of active defense” (strategi aktivno oborony), which was referred to in the speech, and later article, by the Chief of the General Staff Army General Valery Gerasimov in 2019.

It was intended to be an extension of Russian pursuits in precision strike covering both nuclear and conventional capabilities while giving the ability to overcome enemy air defence. Russia initiated the hypersonic weapons programme in the 1980s as it pursued the development of a cruise missile warhead capable of performing an evasive maneuver to overcome enemy air defences, the Metorit strategic supersonic missile and the Kh-90 missile, known as the Hypersonic Experimental Aircraft. Only one weapons system, the Kinzhal, was developed as a sub-strategic system i.e. with a range of less than 5,500 km.

9-S-7760 Kinzhal (Dagger) is an air-launched ballistic missile (ALBM) and is a modified variant of the 9M723 Iskander ground-launched ballistic missile. It is launched by the MiG-31K missile carrier—a modified version of the MiG-31 Foxhound interceptor.The MiG-31 launches the missile at high (i.e. supersonic) speed, thereby boosting the flying velocity of the Kinzhal. The missile then follows an aero-ballistic flight profile as it flies at the stratosphere boundary to minimize air resistance and eventually reaches Mach 10 speed.

It is capable of maneuvering throughout all phases of its flight trajectory thus giving it the capability to evade the enemy air defences. Presently it is launched only from the MiG-31K that gives it a range of around 2,000 km from the point of release from the aircraft. It has also been reported that the Kinzhal will be launched from the supersonic Tu-22M3M Backfire bomber, which is under development, and, further in the future, the Su-57 Felon fifth-generation fighter aircraft.

Why is it difficult to engage Kinzhals

To understand the difficulties in engaging the Kinzhal, the launch and flight sequence of Kinzhal needs to be understood. The Kinzhal armed MiG-31K fighters remain air borne and on patrol awaiting the launch command. The details of the target to be engaged by the Kinzhal are passed on to the MiG-31K via a secure data link.

During its entire flight path, the Kinzhal manoeuvres randomly using thrust vector control and fins.

Thereafter, the target data is used to programme the Kinzhal’s autopilot, load the target’s radar image into the missile’s seeker, and computes the launch point of the missile. Once the launch sequence is initiated, the MIG-31K flies autonomously, to accurately achieve missile launch parameters. Once the parameters are achieved, generally at around 20,000 meters altitude and Mach 2 speed, the aircrew releases the missile.

On release, the Kinzhal climbs rapidly to the stratosphere boundary to minimize drag resistance and it switches to thrust vector control. Upon reaching the stratosphere boundary, the missile flies horizontally and accelerates to Mach 10. During its entire flight path, the Kinzhal manoeuvres randomly using thrust vector control and fins. In the terminal stage, it switches on its active radar-homing seeker to home on to the target, striking it with a claimed CEP of 10 m.

During this entire sequence, there exists two possible options of engaging the Kinzhal. Firstly, shortly after its release from a MiG-31K when it is not maneuvering, and secondly, at terminal stage, when the Kinzhal is homing on to the target. To engage the Kinzhal the air defence system needs to be within range and should have the capability to a target at that high speed. Given that Patriot has a range of 30,000m, the launcher needs to be located near the Kinzhal’s release point.

As the Kinzhal is generally released well within Russian territory, this possibility appears implausible. The second option is to have the engagement carried out during Kinzhal’s terminal stage as it homes on to the target. At this point, the speed of the missile would be in the range of Mach 10 and well beyond the known capabilities of air defence systems in service as the inertia of the interceptor missile would rule out accurate tracking of the target.

It was claimed that the ICBMs will always get through. Even this claim has been challenged and constrained.

This brings out two possibilities- either the Ukrainian claims are false; or the Russian claims of Kinzhal being a hypersonic missile. A couple of points need consideration. One, no physical evidence has been presented by Ukraine to support its claims, these claims are just talk and need not be taken seriously. Two, YuriiIhnat, spokesperson for the Air Force of the Armed Forces of Ukraine, stated on a TV show that since the start of the SMO, Russia had launched 300 Kh-22 missiles at Ukraine, none of which were shot down by air defense systems.

The Kh-22 Storm is a supersonic cruise missile that flies at Mach 4.6. If the Ukrainians are, admittedly so, unable to engage the Kh-22s, their claims of shooting down Kinzhals are just talk made for a select audience and are not to be taken seriously.

The fact remains that Hypersonics are “unstoppable” as on date.

Conclusion

In 1932, Stanley Baldwin in his speech to the British Parliament, “Fear of the Future” used the phrase that “Bombers always get through.” Baldwin claimed that modern bombers had the capabilities needed to conduct a strategic bombing campaign to destroy a country’s cities, and there was little that can be done to counter it. The modern air defence changed that perception as they limited and restrained the bombers from “always getting through.”

Next, it was claimed that the ICBMs will always get through. Even this claim has been challenged and constrained. Now the votaries of hypersonics make similar claims about them being unstoppable. While it may seem so today, it is only a matter of time that a counter to this new threat is developed and operationalized for the hypersonic defense may be difficult but is still a tractable problem.

Rate this Article
Star Rating Loader Please wait...
The views expressed are of the author and do not necessarily represent the opinions or policies of the Indian Defence Review.

About the Author

Col Mandeep Singh

An Air Defence Gunner, commanded the Regiment during Operation Parakaram and later along the LAC.

More by the same author

Post your Comment

2000characters left