Agni-V ICBM marks India’s arrival as a Missile power

Source: http://defencenews.in/defence-news-internal.aspx?get=new&id=Gzvi/Ubeg0A=

This morning’s maiden canisterised launch of the Defence Research and Development Organization (DRDO) developed Agni V Intercontinental Ballistic Missile (ICBM) marks the arrival of India as a missile power, no two ways about it. The missile struck its designated target area somewhere in the Southern Indian Ocean within just 20 minutes from launch. With a range of ‘easily more than 5500 km’, one finds that India now has the ability to hold all of China’s Eastern Seaboard cities at risk from Peninsular India. But again, there is more to this missile than its range capability. In technological terms this missile represents the coming of age for India of a very long range payload delivery capability that is both rather accurate as well as survivable.

First up, Watch the video of this morning’s launch courtesy DRDO.

The Agni V has a contemporary 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 as well as India’s own IRNSS to remove accumulated errors in their measurements.

However, IRNSS even after it is fully deployed this year will not be able to provide coverage to the Agni-V over much of its trajectory, and foreign SATNAV systems cannot always be relied upon for targeting purposes as the signal itself may be switched off especially on the home stretch. Nevertheless, DRDO is confident that the combination of RLG-INS and MINGS, the latter being essentially a MEMS-based miniaturised magnetometer incorporated for redundancy, is capable of providing the ‘necessary’ accuracy at max range for the Agni V. The RLG itself has a bias drift of only 0.01º/h and this represents a significant improvement over older missiles in the Agni series which use a dynamically tuned gyroscope-INS coupled with a star-sighting system for navigation.

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 led to the onboard computer (OBC) weighing almost 5 kg. However, Indian missiles will now incorporate system on chip (SOC) based OBCs 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 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 will 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 such 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 a classic ‘wooden round’ i.e a canisterised missile system transportable by road and rail ready to launch on demand, with an almost maintenance free stowage and storage life of 10 years or so. The Agni-V in canisterised configuration consists of a mission ready missile, a gas generator for ejecting the missile out of the canister to a height of about 30 metres at which point the Stage-I motor ignites, and the canister itself that provides protection besides serving as a cold-launch tube. This cold launch scheme obviates the need to add a jet deflector to the launcher and also allows the missile to be launched from relatively unprepared strips since the strength of the launching surface becomes far less of a concern. A fully automated inspection system based on air-coupled ultrasonic technique for the Agni 5 canister has been developed as well.

The missile canister sits on the Agni-V’s Transport-cum-Tilting vehicle-5 (TCT-5), designed and developed by DRDO’s Vehicle Research and Development Establishment, Ahmednagar. TCT-5 has a 140 ton gross vehicle weight hydraulic gooseneck steerable trailer launching mechanism with overall dimensions of 30 m (length) x 3.2 m (width) x 4.4 m (height). It has an electronic controller for all auto and remote operations, a 23 kVA genset, a PTO driven hydraulic power pack and can therefore carry out launch operations without any external power source and logistics. The Agni-V itself is 17 metres long and has a launch weight of about 50 tons with a 1.5 ton payload.

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 previously released pictures may turn out to be rather manoeuvrable making things difficult for emerging Chinese terminal anti-ballistic missile (ABM) defences. 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 as well. All three stages of the Agni-V in any case have flex nozzles control systems which enhance manoeuvrability during flight.

Two more tests in the canisterised configuration will be done before the Agni-V is inducted into the Strategic Forces Command. The Agni V design may also serve as a baseline for a longer ranged and heavier missile that will carry multiple independently targetable re-entry vehicles (MIRV) and this missile may be designated Agni-VI. 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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