Hypersonic Weapons – ‘the New Age Arsenal’

Hypersonic weapons are ‘big news’ these days. One of the virtues that has propelled these so called ‘new age weapons’ to high eminence is the claim that these are ‘unstoppable’ by any known air defences in the world today.

Expectedly therefore, the Chinese test of its hypersonic missile in Jul and Aug last year made a huge uproar both in the international media, as well as, in the strategic community. The assessed capability of the weapon was couched in eye-catching lines… ‘Unstoppable’; ‘went round the globe before cruising towards its target’; missed the target by a ‘dozen miles’ only.

This work attempts to make a sense of the Chinese hypersonic threat in the larger perspective and flags its relevance and applicability in our scenario.

Layout

The paper flows in this manner:-

1. Putting hypersonic weapons in the perspective.
2. The Chinese hypersonic weapon capability.
3. Some inferences and reflections.

Putting Hypersonic Weapons in the Perspective

For the reader to appreciate what China has achieved and why it is so significant, a word about the ‘uniqueness’ of hypersonic weapons may be essential. This is briefly covered.

‘Uniqueness’ of Hypersonic Weapons

1. In definitional terms, hypersonic simply relates to speed. In that a vehicle with a speed greater 5000 km/h is a hypersonic vehicle. Taking the speed of sound in the air to be about 1235Km/h a hypersonic weapon will therefore be the one that can fly at 5 times the speed of sound (or 5 Mach) or more. To get a better perception as to how fast is that; the above speed will correspond to some 1.6 km in one second! ^[1]
2. Second characteristic aspect of hypersonic weapons is its flight path. In that, most of the hypersonic weapons remain endo-atmospheric. Implying that the flight path of the hypersonic kill vehicle remains within the atmosphere (Below 80-100 km altitude)^[2]
3. The third signature of the hypersonic weapons is their being all-the-way powered. This starkly differs from the Ballistic missiles which have a characteristic feature of getting an initial boost (upon launch) followed by the sustainer boost (for longer range missiles) only upto some point in their flight.

   Boosted like this, the missiles may either remain endo-atmospheric or may go well outside the earth’s atmosphere (exo-atmospheric). After the boost phase is over, the missiles follow a ballistic trajectory. At some point in their flight, closer to the target, exo-atmospheric missiles re-enter the earth’s atmosphere and at a pre-designated point, launch single or multiple warheads (latter called Multiple Independently Targetable Re-entry Vehicles or MIRVs). The ballistic trajectories are highly predictable and hence defeat-able.

Implications of Uniqueness

1. Unstoppability

   a. Every air defence weapon system be it on ground/air/sea/sub-surface/space, which may be employed to counter a hypersonic warhead essentially follows a five stage cycle which includes the following :-

   i. Detection of the incoming threat (either from a cold start or from a stand-by state or from a fully deployed stage).

   ii. Identification of the threat asto friend-or-foe(IFF).

   iii. Designation of the identified hostile target to the selected kill system.

   iv. Tracking of the target by missile guidance/fire control radars.

   v. Launch of kill vehicle and its guidance to the end-game or to a point after which the on-board guidance system of the kill vehicle takes over.

   b. While most of the above stages today are automated and system-controlled with minimal man-in-the-loop delay, but still, a typical cycle may take from less than a minute to a few minutes.

   c. With speeds > 5 Mach (in fact 8-20 Mach), the hypersonic weapons do not permit this cycle time to the conventional air defence systems. Hence these become unstoppable by such systems.

2. Unpredictability

a. While the ballistic missiles (both endo, as well as, exo-atmospheric) follow a highly predictable ballistic trajectories after the powered phase, the hypersonic weapons do not do that.

b. Being all-the-way-powered systems these can follow any user-defined trajectory not letting the defender predict the flight course or the impact point.

c. This makes such weapons unpredictable.

3. Disproportionate Threat Footprint

The combination of two factors, namely, tremendous speed and unpredictable trajectory, makes it possible for a hypersonic weapon to keep a very large area under its threat foot-print. In that, its capability to instantly and unpredictably change the target and area of strike prohibits the defender to judge impact point with any assurance.

Confronted with a possibility of strike with hypersonic weapons, a defender will therefore have to up his alert across the entire defended zone.^[3]

4. Hugely Enhanced Kinetic Kill Effect.

Apart from the lethality packed in the warhead per se, the huge kinetic energy packed in the vehicle (the velocity vector is squared, KE = ½ Mass x Velocity2) enhances the kill effect of such vehicles many times. According to one assessment, a hypersonic vehicle cruising at Mach 6 will have 36 times more kill capacity than a comparable ballistic missile.

5. Speed as Stealth.

Derived from one of its main virtues of speed, hypersonic warheads possess ‘stealth’ muscle by default. The aspect of un-detectability as driven by speed in allowing no time for defender’s sensors to detect and identify the threat is interpreted as the capability of remaining ‘invisible’- the DNA of stealth. The catch-phrase, ‘speed is the new stealth’; thus finds its relevance

Variants of Hypersonic Vehicles

1. The Scramjet Miracle

The capability of achieving speeds far in excess of the hypersonic thres hold of Mach 5 (Mach 8-14 and more) is made possible through a technological breakthrough called the Scramjet Technology.

As opposed to a normal ram jet engine (like the one on an aircraft) which when driven against the wind (take-off run) burns the mixture of incoming air (ramming on the engine face) and the aviation fuel at subsonic speed thus producing speeds up to Mach 3 or Mach 4, scramjet engine has the capability of sustaining this combustion at supersonic speeds producing escape gases at such tremendous speeds that it propels the hypersonic body at speeds far in excess of the hypersonic limits. Detailed explanation of scramjet is beyond the scope of this work.^[4]

Variants of Hypersonic Arsenal

With speeds achieved as above, the hypersonic weapons have two variants.

1. Variant 1: Hypersonic Cruise Missile ( HCM)

Based on Scramjet technology, HCM are all-the-way powered missiles that are able to achieve speeds of 5-15 Mach. In this speed cycle, the conventional ballistic missile cycle of booster and sustainer motor is replaced by a powerful scramjet rocket motor which achieves the targeted speed early in its trajectory and thereafter fires continuously to maintain that level. An incredible engineering marvel indeed!

2. Variant 2: Hypersonic Glide Vehicle (HGV)

In this variant, the hypersonic warhead called the HGV is carried by another powerful missile normally a ballistic Missile (may be an ICBM). As the missile speeds up on strong boost and sustainer output, a stage reaches when the shock waves produced by this flight starts acting as ‘lifting surfaces’and greatly reduce the lift-to-drag ratio. Riding on these shock waves, the HGV detaches from the carrier and starts to cruise in the hypersonic regime. Because of the phenomenon of riding the shock waves, HGVs are also called ‘wave-rider’ weapons.

It would have now become clear to the reader why hypersonic weapons are making such an uproar and why would a country want to possess them. The front-ranking countries that hold hypersonic weapons are Russia, China, US, in that order. As per one open source, the countries which fall in the category of developing hypersonic weapons are France, Germany, Japan, North Korea and India.^[5]

The Chinese Hypersonic Weapon Capability

A Word about the Journey

Chinese development of hypersonic weapons cannot and should not be seen in isolation. It is just one part of the dragon’s overall design to boost up its defence and aerospace capability by developing more and more technologically-enabled platforms - never mind how the technology comes (develop/steal/reverse engineer??)

Super stealthy aerial platforms (J 20, FC 31), armed-to-the-teeth attack helicopters ( WZ9/10/19), state-of-the-art AWACS ( KJ 2000, KJ 500) , full-spectrum unmanned arsenal to include intelligence, surveillance, target acquisition and reconnaissance (ISTAR) vehicles, dedicated combatised platforms, stealthy unmanned aerial systems or UAS, drone swarms (Wing Loong II, GJ 1, GJ2, to name a few) , a surface-to-surface missile (SSM) arsenal spanning the range from 550 km -(DF1 - SS2) to 12000-15000+ Km (DF41- CSS X 10 the next generation ICBM with single/three/six/ten MIRV warheads), active electronically scanned array (AESA) radars, quantum futuristic radars, Beyond Visual Range Air-to-air Missiles or BVRAAMs (PL 12, PL-15 etc.), supersonic Anti-radiation Missiles or ARMs (KH 31P, YJ-91), laser-guided and satellite-guided bombs, nuclear-powered submarines both ballistic missile submarines, as well as, fleet submarines, anti-satellite (ASAT) weapons, co-orbital killers…the list goes on and on to reach hypersonic missiles. The above list is by no way comprehensive). ^[6,7]

The ‘why’ of this build up though well known is outside the scope of this work.

Cutting to hypersonic capability while the run-up developments must have been on for many years, open sources report that active development of hypersonic arsenal came to notice sometime only in 2017.

Some noticeable events each relating to the achievement of a hypersonic capability are briefly stated:

Event 1

The first salient event took place in May 2018 when an HGV test was reported. The boost vehicle was a DF 17 (solid-fuelled road-mobile medium range ballistic missile, range- 1800-2500km). DF 17 is capable of carrying a HGV warhead DF-ZF.

The wave-rider phenomenon took place as DF 17 soared; the HGV got detached and flew a range of 1400 km. The target was in the Xinjiang Province. The HGV achieved an accuracy in ‘meters’ (incredible, if true) .^[8,9]

In the years that followed, the news coming from China made it known that HGV technology will become a part of Chinese nuclear strategy with DF 17 achieving the capability of delivering a nuclear HGV warhead by around 2020.

Also with the passage of time reports leaked that china was trying more SSMs as carrier vehicles. One such SSM was the DF 41 (fourth generation solid-fuelled strategic range ICBM Range - 12000-15000 km)

Event 2

The second hypersonic event took place closer to the first one. It was on 03 Aug 2018, that China announced successful testing of a ‘hypersonic aircraft’ calledStarry Sky -2 or Xingkong -2 in Chinese. It was an HCM capable of carrying both the conventional, as well as, nuclear weapons.

True to the hypersonic weapons, Starry Sky 2 was claimed to be unstoppable by any conventional air defence and Ballistic Missile Defence (BMD) weapon.^[10]

Soon after the launch from an undisclosed site in western China, the HCM achieved a speed of 5.5 to 6 Mach (6738-7350 Km/hr). It flew for about 10 minutes and achieved an altitude of 30 km. The weapon precisely hit its intended target. During the flight, Starry Sky flew an unpredicted trajectory being an HCM.

During its course, it made some wide turning manoeuvres at large angles. In addition to HCM process, the flight also tested some related aspects required to sustain the hypersonic process. These included cutting-edge technologies, such as a domestically developed heat-balance thermal protection system. Most importantly, the achievement of the HCM concept per se, was fully corroborated.

In Sep 2018 soon after the above tests, China reportedly conducted the tests of three "wide-speed-range-vehicles". These were codenamed as D18-1S, D18-2S and D 18-3S respectively. All these were scaled down hypersonic aircraft models of multiple designs whose speeds will be adjustable for a precision strike of an unstoppable nuclear capable weapon.^[11]

The Current Event

The current event relates to July-Aug 2021(Jul 27 and Aug 13) when China launched another hypersonic weapon. There were several unpredicted features in this launch. Following points are stated as to the launch^{[12,13,14,15]}:-

1. It was an HGV which was launched with Long March rocket.
2. Long March actually carried the China’s lunar probe named Chang’e-5. In addition, it also carried an HGV.
3. Once the wave-rider phenomenon was achieved (speed reported 5 Mach) the HGV got detached and hurled towards its intended target.
4. The flight course took the missile over the South Pole. Experts opined that such a manoeuvre will permit striking strategic US targets from the South, thus completely ducking the US missile defence systems optimised for countering the threats from the North and NE directions.
5. Closer to the target something unprecedented happened. The HGV itself fired some sort of an air-to-air missile which shot off and plunged in the water, seemingly not directed towards any particular target.
6. China covered up the incident by putting out the story that it tested only a ‘routine spacecraft’ to check out if it was still usable. As to the mysterious missile launch, the cover story was that it was a supporting device that separated from the spacecraft, this in any case was to burn off on re-entry into the atmosphere.
7. Various possible capability options are being ascribed to the above unprecedented event. One opinion has it, that it was a hypersonic air-to-air missile designed to kill the missile defence warheads of the adversary that might be launched to kill the HGV.
8. According to another opinion, it could be satellite killer with huge kill capability. Such a killer missile could threaten a spacecraft in low earth orbits, a portion of the space the Long March traversed in taking the HGV to the point of maturing of the wave-rider phenomenon^[16]
9. The HGV was reported to have missed the target by more than 20 miles (32 km). Experts opine for such a long trajectory, considering that it was a first attempt, such a capability was laudable.

Some Inferences and Reflections

Going beyond the aforesaid following inferences are drawn:-

1. China is on the road to maturing its hypersonic capability which is currently at an advance development and testing stage.
2. The above statement is made very cautiously in the understanding that while developing the capability verticals for a hypersonic strike capability is one action, putting them together into an operational weapon system, is quite another.
3. Such an operational system will not only require a launch worthy HCM or an HGV, it would also require a ‘global-look see’ capability of surveillance and target acquisition systems complete with communications and connectivities, and a matching BMC2 system that can effectively control a hypersonic strike from target selection to missile guidance leading to the end game phenomenon.
4. In the above context open source report that while China has built dual-use space and counter space capabilities, it is the sense of the author that a fully-operational hypersonic weapon complete with its surveillance, target acquisition, missile guidance and BMC2 is still a few years away. ^[17]
5. It is without doubt that run-up preparations to acquire a full-fledged hypersonic weapon system are underway at a fast pace. Hence only a few years is the estimated time from the current testing to operationalization status.
6. As hinted very briefly earlier, the capability being developed along both the HCM as well as the HGV route is not stand alone. It is a subset of a full-spectrum superset aimed to place China as a real contender of the top slot in defence and aerospace power hierarchy in the world. No wonder the Jul/Aug 21 launch made such uproar in the US.
7. That said Russia is a different story which may pose a totally different terms of reference for China, requiring it to do an uphill ‘catch up’ act. This is stated in the understanding of President Putin’s multi-pronged efforts to revive the USSR aura along the threat lines of nuclear war^[18]

. This is a huge vertical by itself and is not discussed any further.

8. On the hypersonic front as well, Russia is a mighty power - Zircon Hypersonic Missile Mach 8 (9878.4 Km per hour), Avangard HGV on board a liquid-fuelled ICBM reportedly reached Mach 20!^[19,20]

(not discussed further).

9. Leaving the race to helm aside, it is the sense of the author that on the hypersonic crossfire of China (competition or strike) there are other potential adversaries before India.
10. That however gives no reason for any complacency in preparing ourselves to counter possible Chinese hypersonic attacks. Very broadly these will demand the following in times to come :-

a. The Detection Challenge

At the outset, the current national level BMC2 system for air defence and ballistic missile defence (Integrated Air Command and Control System or IAACS) must start forging linkages with space based surveillance systems to achieve a global look-see capability to detect hypersonic launch events.

Such a forward integration is a great possibility given our capability as a strong space-faring nation – all credit to ISRO.

The above integration must not only, aim to forge a space based global surveillance capability, but also, aim to connect the sensors in multiple domains with the kill systems on land, sea, air and space. It is a monumental challenge involving multi-dimensional and multi-platform integration.

b. The Kill Challenge

As conventional air defence and BMD based kill systems will prove to be toothless when faced with hypersonic threats. The weapons required will have to produce an ‘instantaneous soft kill’.

Such a kill is possible with the futuristic soft-kill weapons based on multiple kill mediums such as laser, high power microwave (HPM) and charged particle beams (CPB).

It is stated that while the laser systems in various stages of maturity are nearing reality, the other two are still far. Further technical discussion on the same is not covered owing to space constraints.

11. All these capabilities are easier stated than built. Forging surveillance and target acquisition capability itself across ground, sea, sub-surface, air and space is a herculean challenge; mating the same with suitable kill systems which themselves are in the development cycle is far into the years.
12. The good news is that not only there is awareness about developing counter hypersonic capability but also some work is already underway. The same being in niche classified domain is not stated here.
13. On the weapon front, the hypersonic class weapons are becoming a reality sooner than later in India. In this context, following is briefly stated:-

a. DRDO on 07 Sep 2020 demonstrated an unmanned scramjet hypersonic vehicle listed as High Speed Technology Demonstration Vehicle (HSTDV). It reached a hypersonic speed of Mach 6. The launch met the targeted parameters. The third trial of HSTDV is planned for early 2022.



b. SHAURYA the surface-to-surface tactical missile has a hypersonic speed of 7.5 Mach (9187.8 km/hr) and a range of 700 m.
b. BrahMos II under development is slated to have a speed of about Mach 7 (8775Km/h) with a range of 600 Km. Latest test fire was on 20 Jan 2022.^[21]

c. The BMD interceptors of Programme AD of DRDO (AD 1 and AD2) are supposed to be in the hypersonic range (details classified).

14. So where does that lead to country-to country? A viewpoint:

a. China testing hypersonic weapons both on the HCM and HGV route.
b. This is not stand alone but a part of the ‘whole’ being developed with a design in mind.
c. The real threat is still at horizon. Cutting edge threat to bear strike status as an integrated operational weapon – a few years away.
d. While India may not be on the hypersonic competition/strike cross-wire of the dragon, it is no reason to underplay a potential threat.
e. Work therefore going on to build capabilities against possible hypersonic strikes.
f. Initial developments are underway but it will take many years to operationalisation.
g. That said, weapon-to-weapon hypersonic strike capability realised on some platforms, some others in the pipeline.

15. Having stated this see-saw of hypersonic matrix, the bottom line is India must continue to build defences against a future hypersonic strike from our not-so-friendly neighbour.

Endnotes

^[1]"What are Hypersonic Weapons", at www.economist.com. Accessed on 20 Jan 2022.
^[2] “Endo-atmospheric,” at www.globalsecurity.co, Accessed on 20 Jan 2022.
^[3]"Cruise Missiles", at www.en.wikipedia.org.Accessed on 20 Jan 2022.
^[4] ""Scramjet engine technology," at wwwisro.gov.in. Accessed on 20 Jan 2022.
^[5] “Explainer why there is a brouhaha over Chinese hypersonic missile test and how other nations fare,” at wwwwionews.com. Accessed on 22 Jan 2022.
^[6] “Power behind arrogance: Assessment of China’s air and missile arsenal,” at www.vifindia.org.Accessed on 22 Jan 2022.
^[7] “Changing contours of air threatand its implications in our scenario,” at www.vifindia.org.accessed on 22 Jan 2022.
^[8] “Hypersonic weapons: an analysis, “at www.vifindia.org. Accessed on 22 Jan 2022
^[9]https://economictimes.indiatimes.com>hgv:china's -advanced-hypersonic-missile-threat -to-India.>Accessed on 23 Jan 2022.
^[10]https://www. indiatoday.in>world's-first-hypersonic-aircraft-that-can-fire-nuclear-warheads-successfully-test-fired-by -China.Accessed on 23 Jan 2022.
^[11]"China tests three hypersonic missiles at one go," at www. economictimes.indiatimes.com. Accessed on 23 Jan 2022..
^[12] “China tests new space capability with hypersonic missile,” at www.ft.com. Accessed on 23 Jan 2022.
^[13] “China hypersonic missile test showed unprecedented capability,” at www.bloomberg.com.Accessed on 24 Jan 2022.
^[14] “hypersonic: China Hypersonic missile test: All you need to know,” at www.timesofindia.indiatimes.com. Accessed on 24Jan 2022.
^[15] “China launched second missile July hypersonic test, reports say,” at www.the guardian.com. Accessed on 24 Jan 2022.
^[16] “China hypersonic missile shows XI’s interest in launching orbital strikes, “at www. Hindustantimes.com, Accessed on 24 Jan 2022.
^[17] “China’s counter space capabilities,” at www.claws.in. Accessed on 24 Jan 2022.
^[18] “Threats of war and nuclear war : Putin’s efforts to revive Soviet Union,” at www.realcleardefencse.com. Accessed on 24 Jan 2022.
^[19]https://www.dailymail.co.uk>what-is-russia's-avangard-hypersonic-glide-vehicle. Accessed on 25 Jan 2022..
^[20]https://www.en.wikipedia.org>avangard-hypersonic-vehicle. Accessed on 25 Jan 2022..
^[21] “BrahMos II test fired, “ atwww.pib.gov.in. accessed on 25 Jan 2022.
(The paper is the author’s individual scholastic articulation. The author certifies that the article/paper is original in content, unpublished and it has not been submitted for publication/web upload elsewhere, and that the facts and figures quoted are duly referenced, as needed, and are believed to be correct). (The paper does not necessarily represent the organisational stance... More >>