Friday 20 April 2012

Trajectory of fire: Agni -5


The declared range is political. The demonstrated capability is not. Agni V truly epitomises the maturing of India's missile prowess and is a harbinger of many more technological successes to come. Far from being a "me too" effort to the P-5s (minus the UK) payload delivery systems, the solid-fuelled Agni V is a contemporaneous system exhibiting the state-of-the-art in ballistic missile developments. If production-ised quickly, it would give India the "omni deterrence" that one often hears in DRDOspeak.
Well, even if we look at the missile's stipulated range of "more than 5000 km", one finds that India now has the ability to hold all of China at risk from, say, the eastern states of India. But again, there is much more to this missile than its range capability. For one, the Agni V (like the Agni IV launched late last year) uses an extremely potent guidance package that utilises an indigenous ring laser gyroscope inertial navigation system (RLG-INS) coupled with a micro-inertial navigation system or MINGS. Both the RLG-INS and MINGS are capable of receiving multi-constellation updates from satellite navigation systems such as the American NAVSTAR GPS and the Russian GLONASS to remove accumulated errors in their measurements.
However, in the Indian scenario, foreign SATNAV systems cannot always be relied upon for targeting purposes and this feature of the Agni V's navigation system (i.e the ability to receive satellite updates) will come into its own once India establishes its own satellite navigation system. In the interim, it seems that some quarters in DRDO are confident that the combination of RLG-INS and MINGS, the latter being basically a MEMS-based miniaturised magnetometer, is capable of providing sub-200 metre circular error probable (CEP) accuracy at max range for the Agni V. Notably, this may improve considerably if a military grade signal from a SATNAV system can be used for updates.
In any case, the RLG-INS + MINGS guidance package represents a generational jump over older missiles in the Agni series which essentially use 1970s vintage INS coupled with a star-sighting system for navigation. There has even been speculation that the Agni II is capable of receiving updates from an earth station to remove accumulated errors. However, such a set up is naturally less accurate and prone to failures, as compared to the new navigation systems being used.
The superior accuracy of the Agni V can also be attributed to the incorporation of a much more powerful onboard computer. In the past, operating such processors came with weight and space penalties, given that the PCB based hardware enabling such processors consisted of myriad integrated circuits which resulted in the total weight of the onboard computer to reach almost 5 kg. However, Indian missiles will now incorporate system on chip(SOC) based computers that weigh just 200 grams and boast 6-7 times greater processor capability. The embedded SOC concept requires very little power and gives far greater leeway in warhead configuration besides enhancing efficiency.
Agni V is not just more accurate, but is also more reliable and indeed survivable. While its 2.0-m-diameter first stage motor is the same as that of the Agni III (which incidentally has gone into production recently) and made of 250 grade maraging steel, its second and third stages have carbon composite casings. This extensive use of carbon composites lowers the weight of the Agni V relative to a similar missile having only steel motor casings.
It also therefore facilitates greater fuel fraction, thereby enhancing range.
Now maraging steel certainly has very attractive features such as ultrahigh strength coupled with high fracture toughness, but comes with a weight penalty when contrasted with composites like glass reinforced plastic. Moreover maraging steel is also rather expensive compared to carbon composites and is naturally subject to the vagaries of nature via corrosion that carbon composites are not.
In the future, even the first stage of the Agni V may use carbon composite motor casings and that would take care of the issue of corrosion altogether and enhance overall structural integrity.
The Agni V also relies on digitally connected multi-channel communications within its body for the control system, thereby reducing a lot of the cabling that would have otherwise gone into these missiles. This serves to reduce the risk of failure in the missile system and increases dependability.
The use of corrosion-resistant composites and digital connectivity within the missile makes it easier in some sense to turn the Agni-V into the classic "wooden round" i.e a canisterised missile system transportable by road and rail ready to launch on demand. Indeed Agni V will be India's first canisterised long-range strike system and puts the country on the path to emulating Russia and China which operate similar road mobile missiles.

Now, while an Agni V locked and loaded sitting in a canister somewhere in India is not exactly what China likes to hear first thing in the morning, the middle kingdom could actually have more to worry about. The Agni V's re-entry vehicle a.k.a warhead shown in the released pictures may turn out to be rather maneuverable making things difficult for emerging Chinese terminal course anti-ballistic missile (ABM) defences. Indeed, an article in Global Times about the Agni V (for those who came late, Global Times is the Chinese Communist Party's tabloidish mouthpiece) may have indirectly acknowledged this when it quotes a Chinese analyst saying, towards the end of the piece, that "for the sake of regional stability, China should continue to develop defense systems against ballistic missile threats," and added that, "China successfully conducted its first ground-based mid-course ballistic missile interception experiment in January 2010, becoming the second country in the world to conduct this kind of missile defence test." Incidentally, the third stage of the Agni V is a conical motor which allows for greater acceleration in flight and makes it more difficult for mid-course interceptors to tackle it.
Ultimately, however, true strength will emerge out of efficacious production of the Agni V and it seems that progress has been made in this respect as well. For one, DRDO, via its government-owned company operated format (GOCO), has set up facilities that will now directly produce various components for the Indian missile programme that may not be available for import, or beyond the capabilities of the private sector.
Of course, the new Agni missile types in a way also show that the Indian private sector may now be coming into its own in defence production as evidenced by the fact that Premier Explosives based in Andhra Pradesh actually fabricated the composite casing for the second stage of the Agni IV.
Beyond composites, DRDO has also developed a new grade of low alloy steel designated DMR 1700 which can effectively substitute 250 grade maraging steel in missile applications, ranging from the skeleton to the 2.0 m diameter motor casing used in the first stage of the Agni V. DMR 1700 is significantly cheaper than maraging steel and may ensure that the production of strategic missiles advances quickly. So, although, we have waxed eloquent on composite motors, thus far an alternative for even more cost effective and quicker production probably exists.
In the next few years, the Agni V will be upgraded to carry multiple independently targetable re-entry vehicles (MIRV) and probably adapted for undersea launch. However, the development that I will truly look forward to is the emergence of the Agni V as an operationally responsive space launch system which essentially refers to the ability to put small satellite payloads into orbit on demand from the military. In an age where China is proliferating anti-satellite systems, that is one capability that India must certainly have.


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