Aircraft Carriers in Age of Hypersonic Weapons

Earlier in February 2020, the CDS, General Rawat made a statement that he would rather, Indian Navy buy submarines, and use money to build air-strips on the far-flung Indian islands in the Andaman, than invest in an aircraft carrier.  A few days later he acknowledged that the Navy had its eyes set on a third aircraft carrier. Aircraft carriers cost a lot of money to build and many resources to maintain and defend. December 2019, Russia announced that it had deployed its first hypersonic nuclear-capable missiles. The Avangard hypersonic glide vehicle, which can fly at 27 times the speed of sound, is the new generation weapon that could hit almost any point on earth and could evade the U.S. missile shield. Launched atop an intercontinental ballistic missile (ICBM), but unlike a regular missile which follows a predictable path after separation, this can make sharp manoeuvres enroute to its target, making it harder to intercept. Avangard reportedly uses new composite materials to withstand temperatures of up to 2,000^o C which may be reached at hypersonic speeds, and can carry a two-megaton nuclear warhead.

          There are over a dozen U.S. hypersonic projects. There focus is on air-breathing boost-glide hypersonic systems. Many private players like Raytheon are engaged. The U.S. anticipates deploying hypersonic weapons in the 2020s, hypersonic drones by the 2030s and recoverable hypersonic drone aircraft by the 2040s. China has tested its own hypersonic glide vehicle (HGV). It displayed Dong Feng 17 (DF-17), at the 70th anniversary military parade. U.S. officials have talked about putting a layer of sensors in satellites to detect the hypersonic weapons earlier. With successful test of hypersonic missiles by Russia, China and USA, there has been a renewed debate on whether the aircraft carriers can survive hypersonic weapons.

Hypersonic Flight

          Hypersonic is a flight through the atmosphere at speeds in excess of Mach 5. At this speed dissociation of air begins to become significant and high heat loads get generated, that could affect a missile’s sensitive inner electronics which need protection without adding extra weight or drag. Scramjet technology uses a booster to reach cruising speeds. The scramjet engine which is designed to compress the high-velocity, incoming air before combustion, then takes over. This ‘air breathing’ technology renders a highly efficient engine at hypersonic speeds. A wave-rider is a hypersonic design that improves supersonic lift-to-drag ratio by using the shockwave being generated by its own flight as a lifting surface, a phenomenon known as compressive lift. The Boeing X-51 Wave-rider and China’s XingKong-2, are wave-riders.

High Speed and Weapon Mechanics

          Kinetic energy is a function of the square of velocity. One-kilogram object delivered precisely at such high speed can be more destructive than one-kilogram of TNT. The speed and altitude at which hypersonic vehicles fly significantly challenge any adversary’s ability to detect, track, target and engage. Both are key for aiding access to hostile environments. This velocity allows to reach fleeting targets well before they get away. Their manoeuvrability allows them to change course up to the last minutes of flight, and achieve a high degree of targeting precision. Low Radar Cross Section (RCS) means delayed detection. Hypersonic weapons are either boost glide or scramjet type. In a boost glide system, a rocket accelerates its payload to high speeds. The payload then separates from the rocket and glides unpowered to its destination. Hypersonic cruise missiles (HCM) which are powered by scramjet are restricted below 100,000 feet; hypersonic glide vehicles (HGV) can travel higher. The relatively lower altitude path helps mask HCM, making invisible to early warning radars. HGVs can maneuver during flight, and so more difficult to intercept, even if detected. By offering combination of the precision of near-zero-miss weapons, the speed of ballistic missiles, and the maneuverability of cruise missiles, hypersonic weapons are a disruptive technology capable of striking in short time. The weapons could be deployed on land, sea and air.

Evolving Hypersonic Weapons

          Russia was the first to field an operational hypersonic weapon. They had unveiled six new ‘invincible’ weapons in March 2018. Russia has successfully tested the air-to-ground hypersonic missile Kinzhal (“dagger”) multiple times with the MiG-31 fighter and is now mounting the Kinzhal on the Tu-22M3 strategic bomber. Russia has completed the fifth test of the ship-based hypersonic Tsirkon (“zircon”) missile, which reaches a top speed of Mach 8, and can threaten land and sea based platforms. In December 2018, Russia successful tested Avangard HGV at Mach 20. Russia plans to arm the HGV with nuclear warheads and deploy it on at least two different types of ballistic missiles sometime in 2020.

          In 2016 China conducted at least seven tests of the DF-ZF glider at Mach 10, and range of 2,000 kilometers, and in November 2017, completed two tests of the new DF-17 medium-range ballistic missile HGV up to a range of 2,500 km. This vehicle may become operational in 2020. In August 2018, China tested the Starry Sky-2, using experimental hypersonic wave-rider technology and reached speeds of Mach 5.5 for 400 seconds. In February 2019, France became the first European nation seeking hypersonic weapons and announced Project V-MaX, hoping to acquire a Mach 5 HGV by 2021. More nations are likely to pursue HCM and HGV capabilities. Russia and India are collaborating on the hypersonic BrahMos II anti-ship cruise missile. India’s Hypersonic Technology Demonstrator Vehicle (HSTDV), is Defence Research and Development Organisation’s (DRDO) scramjet demonstrator for hypersonic cruise missile. The eventual target is to reach Mach 6.5 at an altitude of 32.5 km. A 1:16 scale model of the vehicle was tested at a hypersonic wind tunnel operated by Israel Aerospace Industries. The scramjet engine has been tested in the lab twice for 20 seconds. On June 12, 2019, the HSTDV was tested with the scramjet engine. The test was a partial successful.

Difficulty to Intercept an HCM/HGV

          It’s often claimed that it’s impossible to defend against hypersonic weapons because they are too fast. Ballistic missiles fly at much higher altitudes and follow relatively predictable trajectories, and it is possible to predict the destination using space-based and ground-based early-warning systems. A typical ballistic missile with a range of about 3,000 km, will give about 14 minutes warning. A RAND study suggests that the detection for HGV would be only six minutes prior to impact. Even if detected, there will be a high degree of uncertainty about their destinations. This makes hypersonic missiles suitable for surprise long-range strikes. They can penetrate even the most advanced air defence systems.

          An advanced space sensor layer could be the key to meeting the hypersonic threat. United States is currently working on the development of a new satellite-sensor layer, which presumably would be positioned in low earth orbit (LEO), in order to provide continuous tracking of both ballistic missiles and hypersonic vehicles. It will require a constellation of hundreds of satellites. Meanwhile Russia and China are working on a new generation of over-the-horizon (OTH) radars. These may detect hypersonic missiles thousands of kilometers away. The new Russian Konteyner OTH radar and Chinese J27-A OTH are likely to detect hypersonic missiles 3,000 km away.

          The ‘point defence’ systems like the U.S. Patriot and Terminal High-Altitude Area Defense (THAAD), and Israeli David Sling and Iron Dome, and Russian S-400 can defend small areas against ballistic missiles, which are actually moving faster than hypersonic weapons, but are not maneuverable. So, speed in itself, may not be a barrier for missile defence. These SAMs are unlikely to be effective against maneuverable hypersonic weapons. Russia is developing the S-500 missile interceptor system, and the United States is working on the THAAD-ER (Terminal High Altitude Area Defence-Extended Range) system. Even these systems have been conceived for area defence only. Hypersonic weapons require point defence weapons.

          One way of defending against hypersonic weapons could be through directed-energy systems, in particular, laser weapons. However, the technology is at an early stage of development. US$ 157.4 million was allocated in the FY2020 Pentagon budget for hypersonic defence, out of $2.6 billion for all hypersonic-related research.

Hypersonic Anti-ship Missiles (HASM) Threat

          The threat posed by HASM is of great concern says U.S. DoD in their missile defense review released in January 2020. It warns that the Chinese weapons could hold carrier battle groups at risk. Faster interceptor systems are required to engage HCM head-on or to catch-up in tail-chase. Unlike ballistic missiles, HCM can approach a target from changed trajectory that makes them extremely difficult to target with defensive weaponry. Their inertia alone can cause enough damage to send a carrier to sea-bed. Hypersonic weapons are neither undetectable nor un-interceptable, but the speed of hypersonic weapons increases the distances for reaction many folds. The short warning times may eventually incentivise automated interceptor systems to a degree not previously acceptable, including firing without human approval.

Complexity of Defending Aircraft Carrier

        Aircraft carriers are viewed by many as the Navy’s crown jewels. Naval aviation has grown during the last century into a primary offensive arm with global reach. Typically a carrier battle group includes ships equipped with advanced air-and-missile defense systems. But HASMs pose a unique threat with little intercept time. Intercept geometry for such a high speed missile would be very complex and with low success rate. Most HASM are much smaller as targets, and difficult to see till much closer. Early detection would require multi-layered sensors, including in space, that can track threats. Putting up hundreds of satellites itself is a complex exercise. The highly maneuvering HASM need launch-to-hit tracking. Meanwhile, land-based, air-launched and underwater-launched new hypersonic weapons system to be placed on land, aircraft, ship, and submarine are under development, adding to the complexity. In view of the short flight time of hypersonic weapons jamming or blinding space-based sensors could be an option.

          The debate over the efficacy of carriers in high-end conflict is nothing new, more so since funds are scarce. Potency-wise, what could be more threatening, 2,000 precision HCM or one new carrier, with both costing roughly same? Could hypersonic weapons be the new equivalent of nuclear deterrence and their use considered highly escalatory. Will ground-based hypersonic missiles replace aircraft carriers in the defence budgets? Countries like China have always relied on thousands of long-range precision conventional strike assets. Prompt strike weapons could be a good investment. U.S. is looking at placing hypersonic weapons in the Pacific as a priority. Some analysts are saying that the Navies should reconsider whether to continue investing in carrier aviation or shift the fleet’s resources to other potent capabilities like long-range conventional hypersonic missiles.

Other Threats to Aircraft Carriers

          As on date submarine-launched torpedoes, or cruise missiles can put the aircraft carrier on the run. HCMs are different and even the next generation aircraft-carrier architects have lot to worry. Unmanned submarines are already becoming a big threat, because they can wait indefinitely along the likely avenues of approach, only moving to attack after they detect the carrier. And robot submarines don’t worry too much about how their families will manage once they are gone. Aircraft carriers already consist of a complex system of systems. Their digital linkages are at a risk of cyber-attacks that can degrade the defences. Autonomous UAVs, capable of using both stand-off and close-range weapons, also have the flexibility to overwhelm air-defences. Aircraft carriers are inherently un-stealthy. Their advantage of mobility can be neutralised by using an Orbital bombardment system. Satellites equipped with tungsten rods, or any other kind of kinetic weapon, can simultaneously identify aircraft carriers and attack them, either sinking a carrier or rendering it useless.

Defence Options for Aircraft Carriers

          Die-hard naval aviators feel that finding the moving aircraft carrier, often changing its course and speed, thousands of kilometers away, in a high threat environment, is not easy. Also like weapons against submarine threat evolved, same will happen against HASMs soon, they feel. Jamming enemy communications to prevent flotilla location information reaching HASM launchers will help. Some even claim that Naval aircraft performing combat air patrols could potentially shoot down incoming missiles before they reach the carrier strike group using AAMs designed to shoot supersonic aircraft. One other step could be to destroy some or all enemy weapons platforms before they launch their weapons. This is easier said than done. A pre-emptive own hypersonic weapons strike could take out enemy systems including mobile launchers. Directed energy weapons are a likely option. U.S. Navy has been pursuing hypervelocity projectiles that could be launched from electromagnetic rail-guns or powder guns. They are smaller and cheaper than interceptor missiles, and a ship could carry more of them. They could contribute to both point defence and enemy hypersonic weapons. Ship-based lasers, high-powered microwaves, electronic warfare, or decoys could also make things difficult for HASMs.

          Meanwhile Naval aviation is pushing hard to stem the tide of criticism of the aircraft carriers, their raison d’être. They talk of the lethality, agility and resilience of a full-sized nuclear-powered aircraft carrier and its air wing. A carrier strike group, by its mere presence, can shape events in the nation’s favor, they claim. U.S. has traditionally been platform-heavy. Aviators say that shooting a bunch of missiles doesn’t complete the kill chain. China has always invested more in missiles, whereas America’s investment has always been in air power even though it is more expensive. China is still looking at immediate neighbourhood in the Pacific, primarily Taiwan and Japan, they argue.

          Navies expect carrier battle groups to adapt to the emerging hypersonic threat, just as they did to Japanese kamikazes in World War II and Soviet bombers equipped with anti-ship missiles during the Cold War. The US Navy plans to deploy new unmanned MQ-25 Stingrays and survivable, long-endurance carrier-launched drones that can perform a variety of tasks including combat air patrols.

Conclusion – Offensive Punch Vs. Vulnerability

          Aircraft carriers were always considered instruments of geopolitical influence. Therefore, nations will always seek means to neutralize them. The aircraft-carrier served well for nearly a hundred years. Like manned aircraft, at some point, the game has to be up. Hypersonic weapons break all the rules of the missile defense game. Carriers have to justify their offensive punch vis-a-vis their new vulnerability. China says its new hypersonic missile, the DF-17, can sink U.S. Navy aircraft carriers. Yes, China almost certainly has such missiles and U.S. experts say will sink an American aircraft carrier ‘if fired eight times.’ Chinese also claim that that it would be ‘impossible’ for ‘Western missile defence’ to track or intercept the DF-17. A HCM detected 160 kilometers away would give only one minute to do something about it. Only choices will be to either intercept at launch or fly an object into its path. Chinese HCM could force American aircraft carriers to move further deeper towards eastern Pacific, rendering them less effective. Whether used to make or deter war, hypersonic weapons will bring change. Threat of hypersonic weapons to high value targets like aircraft carriers is real and with very little warning. Is the Navy’s prize possession on its way out? I think ‘Yes’, certainly it will be vulnerable and less effective. There is still a few years of debate ahead.

        Meanwhile India must realise, conventional hypersonic weapons are now have significant deterrent value, even though not equivalent to nuclear weapons. Rapid transformation in disruptive technologies like Artificial Intelligence, cyber weapons, hypersonic weapons and persistent surveillance is already threatening to change the Status Quo in place by nuclear deterrence. Today it is possible to launch hypersonic precision strikes on the nuclear command, communication and critical infrastructure networks. Indian HCM would be a force multiplier against Chinese aircraft carriers. The bottom line is that hypersonic weapons will determine who is ‘precise and ‘prompt’ enough in 21st-century conflict. India has to quickly get onboard and start developing the ‘disruptive technologies’ and also invest in counter-capabilities. It is also time to rethink if we really need and can afford aircraft carriers, and how many.

This Article was written for Defence and Security Alert (DSA) and has since been updated

Picture: BrahMos Missile Credit: gtrocksblog.wordpress.com