Ever since the advent of the anti-ship missile (AShM) in the 1960s, there has been a constant battle for superiority between AShMs and anti-ship missile defence (AMD) systems. The very first AShMs was ashort range air-launched version (HS 293 Fritz X), made by Nazi Germany during the Second World War. Launched by Luftwaffe bombers, they were radio command or camera-guided on to their target by the bombardier, and were used with telling effect, especially against British and American warships in the Mediterranean during the amphibious campaign to liberate Italy in 1942-43. Radio jamming measures developed shortly thereafter by Allied navies negated the effectiveness of these missiles. While the US Navy also developed an air-launched AShM (SWOD-9 Bat) in 1945, it saw very limited usage against Imperial Japanese Navy ships, as the war ended in August 1945.

Development and Use of Anti-ship Missiles

After the Second World War ended, the Soviet Union took the lead in the development of ship-launched AShMs with the highly effective SS-N-2 Styx AShM. While they also developed air and submarine launched versions of the missile, the shiplaunched version had the advantage of being able to carry a heavy warhead, and this along with the liquid fuel in the missile, made it very effective, even against a large warship. Indeed, the first sinking of a warship by a ship-launched AShM was the Israeli Navy destroyer Eilat, which was hit by a SS-N-2 Styx missile launched from a Egyptian Komar-class missile boat off the Sinai peninsula during the 1967 Arab-Israel War. This was followed by the famous attackson Karachi by Osa-class missile boats of the Indian Navy during the December 1971 Indo-Pakistan War, which destroyed almost two-thirds of the Pakistani Navy, besides causing extensive damage to installations and oil storage facilities in Karachi harbour.

China has done extensive test firings of its missiles over the past few years. The US Department of Defense reported that more than 135 live ballistic missile firings were conducted in 2021 (250 were conducted in 2020), which was more than the tests carried out by all other countries combined in the world.

AShMs have been used in all subsequent wars, most notably in the 1973 Yom Kippur War, the 1982 Falklands War, the Iran-Iraq War (1980-88), the First Gulf War in 1990 and the Second Gulf War in 2003. AShMs have also been used with telling effect in the Russia-Ukraine War by Ukraine, illustrated by the sinking of the Russian Navy heavy cruiser, the Moskva, which was reportedly hit by two land-launched Neptune AShMs (the Russians claim it sank because of an internal explosion after a fire on board). A new and worrying development in the 21st century has been the use of AShMs by non-state actors to target both warships and merchant ships – the Hezbollah hit an Israeli Navy Sa’ar 5-class corvette with a Chinese-built C-701 AShM in 2006 and the Houthis have targeted several merchant ships in the Red Sea with anti-ship ballistic missiles in recent months.

AShMs have become deadlier over the years as earlier versions with higher trajectories, which were easier to track and shoot down by ship-based missile and gun systems, have been replaced with sea-skimming missiles travelling at supersonic speeds. While AMD measures (both active and passive) against AShMs have constantly improved, AShMs have retained a slight edge, principally due to the fact that offense always has an advantage over defence, especially if the surprise factor is maintained. However, the recent development of hypersonic anti-ship ballistic missiles (AShBM), in ship, air and land launched versions, threatens to tilt the scales substantially in favour of the AShM. This article examines the development of China’s YJ-21 Eagle Strike Hypersonic AShBM to assess the threat they pose and what can be done to mitigate it.

The Rise of Chinese Hypersonic Anti-Ship Ballistic Missiles

The PLA Navy (PLAN) first released the footage of a test firing of the YJ-21 hypersonic AShBM from the universal launch system of their 13,000 tonne Type 055 Renhai-class cruiser (termed as a destroyer by China) in April 2022. It is estimated that the missile can also be fired from the Type 052D destroyers of the PLAN. There is also an aerial version of the missile which can be fired from China’s H-6 bombers. Guided by the Beidou satellite navigation system, the missile travels at a speed of Mach 6 during the cruise phase and at Mach 10 in its terminal phase. On January 30, 2023, the official Weibo account of the People’s Liberation Army Strategic Support Force (PLASSF) stated that the YJ-21 could not be intercepted by any anti-missile weapon system in the world. The credibility of the claim is supposed to be high as the PLASSF is responsible for data gathering and weapon analysis of all Chinese weapon systems. The Chinese claim that even if the missile is intercepted in its terminal phase, the velocity of the missile fragments is sufficient to seriously damage the target ship. According to US-based intelligence inputs, intercepting the missile is extremely difficult because of their capability to manoeuvre dynamically on re-entry, also making it more effective against moving targets such as ships.

Interestingly, an export version of the missile called YJ-21E had also been publicly show-cased at the Zhuhai Air Show China in 2022, where it had also been claimed that it was being developed for ‘offshore defence’ implying its possible use as a shore-based weapon for sea denial, inconsonance with China’s of Anti-access Area Denial strategy (A2AD). The missile is compact enough to be mounted on mobile carriers as well for use as shore missile battery.

What makes the weapon even more formidable is the fact that the Type 055 cruiser has a 112 Vertical Launch System (VLS) cells, which can carry a combination of YJ-18/ YJ-21 anti-ship missiles, HHQ-9 surface-to-air missiles, CJ-10 land attack cruise missiles, and anti-submarine missiles, which can be carried in any configuration. A recent article stated that the PLAN had war-gamed firing of different numbers of YJ-21 missiles against a Ford Class aircraft carrier group and concluded that a salvo of 24 missiles would sink the carrier after overcoming its defences. It is clear that the PLAN is following the old Soviet (and current Russian) philosophy of large salvo firings against capital warships such as cruisers, destroyers and aircraft carriers, to swamp the adversary’s anti-missile defence systems, and cater for redundancies due to malfunction. While this earlier required a larger number of platforms when the carrying capacity of individual warships using conventional launch systems was limited, the introduction of below-deck VLS on the Type 052-D and Type 055 cruisers, has largely obviated this problem. The PLAN has already commissioned six Type 055 cruisers (of a total planned number of eight), at least two of which would accompany a PLAN aircraft carrier group, or be deployed independently as surface attack units.

It is also relevant to note that the YJ-21 would not be used in isolation in a sea battle. China has several AShMs in its order of battle, which would be fielded on a variety of surface, sub-surface, aerial and land-based platforms, as shown on the table below.

China’s Naval Dominance

China is today the largest navy in the world with 370 active modern front line ships (not including 60 ASCM carrying patrol vessels/smaller combatants). What makes China a formidable maritime adversary is the variety and numbers of anti-ship weapons that it can bring to bear on an adversary within the first island chain, not only from the mainland and from ships/submarines deployed at sea, but also from military bases built on several reclaimed islets in the South China Sea. This targeting area is now slowly extending outwards as the capability and range of Chinese sea, air and land launched weapon systems increases. This fact has been acknowledged in the last few editions of its Congressional Research Service Report on “China’s Naval Modernisation: Implications for US Navy Capabilities”, in which it has clearly acknowledged the PLAN would effectively challenge the ability of the US Navy to maintain sea control in the blue water ocean areas in the Western Pacific during a possible future conflict with China.

It is also notable that China has done extensive test firings of its missiles over the past few years. The US Department of Defense reported that more than 135 live ballistic missile firings were conducted in 2021 (250 were conducted in 2020), which was more than the tests carried out by all other countries combined in the world. This indicates that China is honing both the hardware and software of its missiles through extensive testing and also has a strong domestic manufacturing capability, which would allow it to easily build-up and maintain the inventories needed during a future war.

Countering the Hypersonic Threat

In the face of an adversary with such a numerical and qualitative edge, the measures that need to be taken by other major navies, such as the US and the Indian Navy, could be classified under the development and warfighting heads. As far as development is concerned, this also needs to have two major prongs, offensive and defensive. Offensive measures would include the development of equally or more capable ship, submarine and air launched hypersonic ASBMs/ASCMs (such as Raytheon’s SM-8, Japan’s planned “island defence anti-ship missile” and Hyper Velocity Gliding Projectile (HVGP) and India’s nascent Hypersonic Technology Demonstrator Vehicle (HSTDV)), as also the development (particularly for India) of shore-based ASBMs for pre-emptive attack. The latter option is a particularly good one to combat a future PLAN aircraft carrier group in the Indian Ocean, especially using the favourable geography provided by our island territories. Future AShMs, both ASCMs and ASBMs, also need to be designed with redundant guidance systems (satellite, inertial navigation, infra-red and radio frequency) to increase their survivability against soft-kill measures.

Source: GAO analysis Department of Defense

As far as actual warfighting is concerned, any adversary weapon system is best countered with tactics for a specific geographic environment and the individual characteristics and design attributes of a specific weapon. Chinese AShMs will be most effective in the geographical environment in which they plan to execute their A2AD strategy, which is within the first island chain. However, their effectiveness would be reduced in the open ocean and in a geographical environment conducive to their adversary, such as the north Indian Ocean region. For example, countering this weapon by the Indian Navy (IN) would require a relative numerical superiority of weapon platforms and AShMs in all dimensions – surface, sub-surface aerial and land-based – which should be endeavoured to be made available in the north Indian Ocean. Along with this, an accurate MDA picture would be required for early detection and weapon targeting at maximum ranges, while denying the same facility to PLAN forces. At the tactical level, AMD measures, both soft and hard kill, will need to be developed, to counter the missile after it is fired. Another tactic is to fire different types of missiles at the same time, which confuses the adversary’s air defence picture and facilitates a successful strike.

Way Forward

All this is easier said than done, but needs to be taken up in mission mode by the IN and the DRDO, as also in a collaborative mode with defence partners such as the QUAD countries. Hypersonic ASBMs are already a reality with the PLAN. China is the acknowledged global leader in hypersonic weapons and has also officially announced that it is at an advanced stage of development of even more capable hypersonic ASBMs. Consequently, the threat from such weapons is only going to increase and solutions to counter it need to be found in a time-bound manner.