The Trigger Event

The morning chill on the 21stof Jan 22 got broken with a ‘warm’ news from the DRDO announcing the successful test firing of the Brahmos supersonic cruise missile from its test range in Odisha.

While many will see this as ‘one more test launch’ in sequence of several others, a few will look beyond the bright plume and the thunderous roar of the missile as it rose up towards the sky achieving a significant milestone in sharpening the nation’s cruise missile arsenal. ‘Looking beyond’ as stated, this work attempts to weigh our prowess in the area of cruise missiles and makes a brief comparison of the same with similar capabilities of our potential adversaries. A word on the way ahead thereafter follows.

WHY CRUISE MISSILES ARE SO VERY UNIQUE AND SIGNIFICANT

In order to appreciate why the subject of ‘cruise missiles’ per se has deserved this work in the first place and what was so significant in the launch of on 22 Jan, a word about the cruise missile itself, is considered essential. The same is briefly stated.

The Standard Fit^[1]

The ‘standard fit’ on which is constituted almost the entire arsenal of the land/sea/air launched missile arsenal of various nations are the ‘ballistic missiles’. The word ‘ballistic’ is attributed to such weapons because they follow a ballistic trajectory which means, a missile trajectory that is driven by the earth’s gravitational pull (besides atmospheric drag).

A typical ballistic missile is thrown up in the atmosphere using a booster motor (a rocket engine). For longer range missiles, once this booster motor runs out, the missile is further propelled into the atmosphere by a sustainer motor (another rocket engine). Based on this initial push, the missile now follows an un-powered flight being continuously pulled by the earth’s gravitational force. Such a trajectory turns out to be a parabola.

Based on the above signatures ballistic missiles in general suffer from three major disadvantages:-

1. Detectability

Ballistic missiles generally have high altitude coverage. In that, endo-atmospheric missiles which remain inside the earth’s atmosphere generally remain in the bracket of 50-80 km while the exo-atmospheric missiles which go outside the earth atmosphere, do about 80-100 km.

Such altitudes expose these missiles to the ‘radar gaze’. Long range radars deployed on land, sea or air and the space-based ones with a global-look-see capability can detect the launch of these missiles early in their trajectory.
Once the missile is detected all sorts of counter-measures can be aligned in time (not explained further).

2. Predictability

Predictability is the function of ballistic trajectory. Post the powered phase, the balance of the missile’s trajectory is governed by the laws of physics and aerodynamics. The impact point of such missiles is accurately predictable and hence, defendable.

Only the ballistic missiles which carry the MIRVs (multiple independently targetable re-entry vehicles) can beat the predictability handicap. Exo-atmospheric missiles upon re-entry into the earth’s environment release MIRVs at a point in time towards the end game. Each of these is powered and programmed to cruise to its assigned target all on its own (not explained further).

3. Accuracy

After the powered phase is over, the trajectory of the ballistic missile is guided by the force of earth’s gravitation trying to pull it down continuously, the atmospheric resistance acting as drag and the residual speed of the missile at the end of the powered phase. While the missile is programmed to home on to its assigned target based on satellite/inertial navigation, the end game accuracy is impacted due to above factors because there is amissile-to-missile variation in the residual speed (which is basically a function of how efficiently the fuel of the rocket engines has burnt) and there are unpredictable variations in the atmospheric drag etc. (not explained further). All these impact the accuracy of the missile.

The Uniqueness of Cruise Missiles^[2]

The cruise missile overcomes all the three disadvantages stated above. This is how it is achieved.

Powered all the Way

Unlike the ballistic missiles, which are powered only in the boost or boost + sustainer phase, cruise missiles are normally powered all the way or at least, for a major part of their trajectory.

This is achieved by arming them with air breathing jet engines. These engines burn a huge amount of air and fuel mixture and produce escape gases at such tremendous velocity that the missile achieves a forward speed of several Mach ( 1 Mach = speed of sound= 343m/s or 1234.8 km/h).

Both Shades become Possible

The early versions of the cruise missiles were generally sub-sonic (speed< 1 Mach). As technology provided better and better engines, cruise missiles crossed the sound barrier and entered into the supersonic range. The test on 22 Jan 2022 featured a supersonic cruise missile.

Remain Low – Avoid Radar Detection

Since there is no need to push the missile high into the air for the ballistic phenomenon to happen, the engines powering the cruise missile keep it low/ very low, almost hugging the ground. This ensures that cruise missiles do not get easily detected by radars. In radar scopes, reflected waves coming back from low/very low altitudes tend to get submerged in the ground clutters that fill the screen with electronic disturbances. The missile cruising low hides behind these clutters and remains undetected for large part of its trajectory. Altitude thus acts like a stealth muscle to such missiles.

Lean-Mean: Adding to Stealth

A typical cruise missile is comparatively smaller than a similar ballistic missile. The smaller the size, smaller is the radar cross-section or RCS of the missile. Very briefly, RCS is the degree of detectability of an object to a sensor (radar). Smaller the RCS, lesser will be its chances of a body getting detected by the radar.

Razor-sharp Accuracy

Most cruise missiles follow terrestrial navigation being low/ultra-low flying objects. These use such techniques like dead-reckoning (calculating current position by using a previously determined fix), dynamic terrain-matching, contour mapping, target matching etc. (details not covered). This makes the missiles achieve razor-sharp accuracies to the tune of sub-meters.

The overall accuracy keeps getting continuously enhanced through dynamic course-correction commands, either generated within the missile electro-magnetic loops, or through sources external to the missile. In later generation missiles accuracy is enhanced by an on-board seeker. In this as the missile nears the target in the end game, the seeker (a missile based radar) becomes active, searches and locks on to the pre-determined target whose details are pre-fed (if possible) and goes for the end game with high accuracy.

Warhead

While the overall warhead carrying capability of the cruise missile as a subset of its all-up-weight (AUW) capability will normally be lower than a similar ballistic missile, substantial lethality is still packable in the cruising vehicles. This is due to the miniaturisation technologies impacting warheads. The cruise missiles especially of the later generations are capable of carrying both the conventional, as well as, the non-conventional/ nuclear warhead.

With such takeaways with the cruise missiles, it is no wonder therefore that this arsenal is top-of-the-line in its class . Where are we?

Where is India in Cruise Missiles

BrahMos

A Piece of History

The Indian cruise missile story started sometimes in the late nineties. A joint venture (JV) happened in 1998 between a Russian Rocket Design Bureau NPO Mashinostroyenia (with had a leading presence in the area of space vehicles, ballistic missiles and cruise missiles) and the DRDO. BrahMos Aerospace a JV company came about (Brahmaputra+Moscow= BrahMos). The author is proud to state his one-on-one association with Dr Sivathanu Pillay in later years who is the founder of the JV from the DRDO side.

Following salient points are stated as to BrahMos cruise missiles^[3]

1. Cruising at up to Mach 4, BrahMos has a distinction of being the fastest supersonic cruise missile in the world.
2. While the land attack version and the ship-launched version completed trials and were ready for induction in 2009-10, the air-launched version was operationalized on board SU 30 MKI in 2019^[4]
3. The missile can cruise as low 10m (cruising altitude up to 15 km, terminal altitude as low as 10 m) in the land attack version and from 6ft-150ft in the sea-skimming mode, this makes the missile a hard target to be detected by electronic sensors^[5].
4. As to the range, till the time we were under the restrictions of the Missile Technology Control Regime (MTCR) the range was capped at 300 km (export version 290 km). In 2016 when India became a member of the MTCR, planning started for an extended range (ER) version of the missile as to touch the range of 700-800 km. The targeted range was achieved incrementally. By 2019 a range of 650 km was achieved and by Sep 2020, the range achieved was 800km. Open sources reported that the aim is to escalate this range to 1500km to be able to hit out at strategic targets well outside the tactical battle areas, deep inside enemy territory.^[6]
5. Speed is one region where the BrahMos actually has its USP. Upfront and starting from its initial versions itself, the missile was doing 2.8 Mach. The currently achieved speed is around 4 mach. The idea is to ultimately enter the hypersonic range (BrahMos II> 5 Mach).
6. The parameters being planned are gold class - Speed 8 Mach, Range 1000 km in all the three versions, namely land attack, air-launched and anti-ship. The missile christened BrahMos II (K). ‘K’ as a salute to the Missile man of India and our honourable President Abdul Kalam. The missile is likely to be ready for trials by 2024. ^[7]



7. The speed game delivers many other advantages. The most obvious is the short time of flight which reduces the chances for the adversary to adopt any counter measures including an EW/ kinetic attack on the incoming missiles using its anti-missiles measures. Once the hypersonic barrier is crossed, a new missile capability will emerge that will be so fast from launch to the end game that it will make conventional air defences ‘redundant’.
8. As technology is revamping missile technologies world over, BrahMos is adopting them alongside. In that there is a new generation (NG) of the original 300 km, 2.9-4 Mach missile called the BrahMos NG. Advancement in material technology has permitted reduction in dimensions and weight. Besides, it has better stealth features with reduced RCS, higher electronic attack capability effective against adversary’s electronic counter measures and a greater versatility in the sea-launched version.

Nirbhay Cruise Missile^[8,9,10]

Unlike the BrahMos on the JV route, Nirbhay cruise missile is indigenously developed by the Aeronautical Development Establishment (ADE) under the DRDO. Following important points are stated about Nirbhay:-

1. Slightly smaller than the standard BrahMos (L- 6 m; Brah-8.4 m , dia 0.52m; Brah-0.6m) , Nirbhay remains in the subsonic range of 0.7-0.9 Mach.
2. It pips the basic Brahmos in the range vector to claim a range of 1000km.
3. The warhead carrying capability is similar to BrahMos (200-300Kg). The same could be conventional or nuclear.
4. It does a shade better than BrahMos to be able to cruise at ever lower altitudes ( cruising at 4 km, end game 50m; BrahMos cruising up to 15 km , end game 10m).
5. Sub-metric accuracy is achieved using the inertial navigation system using the ring laser gyro and micro-electromechanical system ( MEMS) based gyro duly assisted by GPS and IRNSS ( Indian Regional Navigation Satellite System).
6. A limited number of missiles stand duly operationalized and deployed on the northern/NE border.

Comparison with Some Other Cruise Missiles

Cruise Missiles of China^[11,12]

China has a significant inventory of cruise missiles covering various range and altitude brackets. These are capable of being launched from land, sea or air. Taken all together, China possesses the capability of launching conventional, as well as, nuclear warheads using the carrier mode of cruise missiles. Following points are stated:-

1. Chinese cruise missiles can be grouped under the following categories;

a. Land attack Cruise Missiles ( LACM)
- Short range.
- Intermediate range.
- Long range.
b. Air Launched cruise missiles (ALCM).

2. In the short range LACM category YJ 18 Cruise missile is ground launched while YJ 18 C is ship/submarine launched. Its range lies in the bracket of 220-540Km and the speed band is Mach 2.5-3.
3. In the intermediate range LACM, China has three cruise missiles belonging to the Hong Nio (HN) series. These are HN1, HN2 and HN3. These have ranges in the bracket of 600-650 km and are capable of carrying both the conventional, as well as, nuclear warheads (upto 20KT).
4. In the long range LACM category China has CJ 10 (Dong Feng or DF10) Cruise missile with an operational range of 1500+ km. This missile also has an air-launched version called CJ10K.
5. In the ALCM category China has CJ 20 (Changjian20) cruise missile launch able from the H-6K strategic bomber (combat radius 2500km). this missile has a range of 2000+ km
6. The cruise missile arsenal forms the part of PLA’s rocket Forces (PLARF).

Cruise Missile Pakistan

^[13]
Pakistan has Babur (HATF VII) cruise missile. Following points are stated:-

1. Babur is a medium range cruise missile in operational status with Pakistan since 2010.
2. Open sources quote a range band for Babur 450-900+km ( Babur IIA/III -450, Babur I, Harbah (ship launched version) - 700Km, Babur II 750 km, Babur IB -900+ km- uncorroborated)
3. The missile is subsonic at 0.8 Mach. It is launchable from ground /ship and has a warhead carrying capability of 450-500kg (conventional or nuclear.

Some Reflections and Assessment

Based on the aforesaid, following points are stated:-

1. A word on the threats we face.

a. China.

i. China has a full spectrum capability of cruise missiles spanning the range bracket from 140-2000+km.

ii. With missile deployed at bases in the Tibet Autonomous Region at say Lhasa, Golmud, Shigaste, Nyingchi, Chengdu etc., the cruise missile reach extends deep inside Indian borders (beyond Tejpur and well into Arunachal).

iii. That said, the nature of high altitude terrain obtaining in TAR will restrict the long range low-level cruise capability of the arsenal to a large extent and would require sharp manoeuvres and turns from launch to the target.

iv. The niche capability of CJ 20 ALCM on board the H-6K will extend the cruise strike capabilityin range and reach.

v. It is believed that precise inertial guidance coupled with satellite based navigation based on the BeiDou Navigation satellites will be used to ensure successful cruise to the target.

b. Pakistan

i. Babur has matured in the Pakistani Strategic Forces Command being in operation now for more than a decade.

ii. A range bracket of 450-900+km capability is a substantial one keeping in mind that the missile is launchable from ground mobile launchers (TELs – transportable erectable launchers) which can be staged well up near the LoC.

iii. Also the plains/deserts/semi-dessert terrain obtaining on the western border is more cruise-friendly.

iv. A large number of targets, well past the TBA into our depth areas will come in the reach of Babur missile.

2. Following points are made as regards own cruise missile arsenal.

a. Notwithstanding the range and depth of Chinese cruise missiles arsenal, we also have a substantial and comparable cruise missile capability.

b. Not only we possess with great pride, the world’s fastest supersonic cruise missile, our constantly increasing techno-capabilities (BrahMos NG, BrahMos ER, BrahMos II etc) makes our cruise arsenal a force to reckon with.

c. With 800+ km range and sub-metric accuracy, BrahMos both on the Western as well as, the Northern Border will be effective across a large number of strategic targets (specific details not covered).

d. Similarly the ALCM on SU 30 MKI will be deadly is in ground strike/ counter air operations (CAO) and counter surface force operations (CSFO) against our potential adversaries.

3. May be there is a case to operationalize the BrahMos ALCM on a long range strategic bomber something like HK-6.
4. Besides the on-going steam on BrahMos where we nearly need to put our effort is Nirbhay. Only a very finite (classified) number of these cruise missilesare deployed. We need to really step up gas and bring in more Nirbhays into the battlefield as ready-to-deploy weapons.

So that is the See-saw of the Cruise Missiles that exists with us and with our not-so-friendly neighbours.
The takeaway message:-

1. WE ARE STRONG ON CRUISE.
2. MAINTAIN STEAM ON BRAHMOS.
3. STEP UP ON NIRBHAY.

Endnotes

^[1] “Ballistic trajectory,” at www.universe today.com.Accessed on 07 Feb 2022.
^[2] “The simple difference between ballistic and cruise missiles<” at www.science.howstuffworks.com. Accessed on 09 Feb 2022.
^[3] “BrahMos Supersonic cruise missile,” at www.brahmos.com.Accessed on 14 Feb 2022.
^[4] “Air launched version of cruise missile ready for serial production, “ aytwww.thehindu.com. Accessed on 15 Feb 2022.
^[5] “Sea-skimming” at www.en.m.wikipedia.org.Accessed on 15 Feb 2022.
^[6] “India now working on 1500 km range Brahmos supersonic missile,” at www.print.in. Accessed on 15 Feb 2022.
^[7] “BrahMos Missile threat , “ at www.missilethreat.csis.com.” Accessed oin 15 Feb 2022. .
^[8]Nirbhay cruise missile test fired..,” at www.hindustantimes.com.Accessed on 16 Feb 2022.
^[9] “Nirbhay/Missile threat,” at www.missilethreat.csis.org.Accessed on 16 Feb 2022.
^[10]Nirbhaynissile, “at www/economictimes.indiatimes.com.Accessed on 16 Feb 2022.
^[11] “China’s cruise missile capabilities…” at www.orfonline.org.Accessed on 17 Feb 2022.
^[12] “ Missiles of china,” at www.missilethreat.csis.org. Accessed on 17 Feb 2022.
^[13]Missiles of Pakistan,” at www.missilethreat.csis ,org. Accessed on 17 Feb 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 >>