Soaring high

Print edition : January 25, 2013

Agni-V, with a range of 5,000 km, being loaded on to the road-mobile launcher in April 2012. Photo: V.V. Krishnan

DRDO Director V.K.Saraswat (left) with DRDL Director A.K. Chakrabarti in front of the canister that is used to launch the Shourya missile, at the Research Centre IMARAT in Hyderabad. A 2008 photograph. Photo: Mohammed Yousuf

Dr.V.G. Sekaran, ASL Director: "It is important not only to make the missile, but to make it able to survive." Photo: THE HINDU

IMAGINE a 50-tonne missile, encased in a 20-metre-long canister, being propelled into the air by a gas generator in a matter of 1.5 seconds. And imagine how much propulsion power the gas generator should pack within it, and how complex the entire operation must be when the missile is fired from a truck big and strong enough to absorb the shock of the blast-off.

That is exactly what the Advanced Systems Laboratory (ASL), the Defence Research and Development Organisation’s (DRDO) missile-making laboratory in Hyderabad, will achieve this year when the Agni-V missile will bolt out of a canister mounted on a Tatra truck from Wheeler Island, off the Odisha coast, traverse more than 5,000 kilometres across the sky, and then splash into the Indian Ocean.

The ASL, founded on September 28, 2001, is the “baby” in the DRDO’s vast missile complex in Hyderabad. The other two DRDO laboratories here are the Defence Research and Development Laboratory (DRDL) and the Research Centre Imarat.

India’s Agni series of missiles, all of which can carry nuclear warheads, are products of the ASL.

Heading the ASL is V.G. Sekaran, one of the architects of Agni-V, which had its successful maiden launch on April 19, 2012. The 17.5-metre-long, three-stage Agni-V, weighing 50 tonnes, lifted off from a rail-mobile launcher on Wheeler Island, made a 20-minute flight during which its three stages ignited and jettisoned on time, its warhead carrying explosives erupted into a fireball, and then it dived into the waters of the Indian Ocean between Australia and Madagascar. The missile was not encased in a canister.

But in the first half of 2013, perhaps in June, Agni-V will soar into the sky from a canister mounted on a launch platform integrated with a truck, which is called a road-mobile launcher. A gas generator placed at the bottom of the canister will erupt into life and push the missile out of the tube. After the missile comes out of the tube, its ignition will take place in the air. In firing such an intermediate range ballistic missile (IRBM) from a canister, a complex technology comes into play. In missile parlance, a canisterised launch is called a “cold launch”.

“We are vigorously working on the canisterised launch,” ASL Director Sekaran said. It is a very involved job in terms of the number of sub-systems that will be employed. The canister will be the biggest made in the country. The ASL has done specialised work in the design and engineering of the canister and the gas generator. It involves aerospace mechanism, too.

Although India’s supersonic cruise missiles BrahMos and hypersonic surface-to-surface missile Shourya are canisterised missiles and the DRDO had testfired them many times, this is the first time it will be firing a missile of the 50-tonne class from a tube. Besides, the missile is 17.5 metres long. While BrahMos weighs only three tonnes and is only nine metres long, Shourya weighs about six tonnes and is 10 m long . So the ASL will perform numerous qualification tests before Agni-V is put inside the canister. Insertion tests will be done. Instead of the real missile, an equivalent will be put inside the tube and a battery of tests done. The work towards this has been going on for the past six months. It will be done in two modes: proving the canister and the missile separately. Then the two will be put together and the final flight trials from the canister will be done. Finally, the DRDO will go in for the missile’s deliverable version.

“We will ensure that all the systems work perfectly before we put the actual missile inside the tube,” said the ASL Director. “We are on the job now. It is in a fairly advanced stage of demonstration. Then we will put the actual missile inside the canister and do a trial launch.”

Although the principles for pushing Agni-V out from a canister are the same as for BrahMos and Shourya, which have been testfired from canisters many times, its engineering becomes very difficult, because of the canister’s size and the missile’s heavy nozzles, said Sekaran. Besides, there is no market for such canisters and not everybody can produce it.

All the Agni missiles, including Agni-III, IV and V, will be road-mobile. That is, they will be launched from trucks because a road-mobile system affords flexible deployment. It can be fired after parking the truck on a highway. It can also be camouflaged. From now on, all missile systems of India will be road-mobile because the DRDO found out in the last 10 years that rail-mobile systems were complex to operate.

The ASL’s mandate was to develop carbon composites and large-sized rocket motors. It achieved a breakthrough in building rocket motor casings made of composites for Agni-IV which led to weight reduction of the rocket stages, ensuring a longer range for the missile. These carbon-composites are used to cover a part of India’s light combat aircraft Tejas, and brake discs in fighter aircraft; they also go into the making of light-weight callipers for polio-affected children ( Frontline, October 7, 2005). Many of the technologies developed by the ASL for Agni-IV were fed into Agni-V.

The laboratory did seminal work when it developed a carbon-carbon composite for Agni missiles’ heat-shields. Agni missiles’ re-entry vehicles (REV) have their electronics and nuclear warhead inside. The REVs are protected by heat-shields. When an REV re-enters the earth’s atmosphere, its carbon-composite tiles should withstand the heat generated, about 5,000° Celsius. Also, the temperature inside the REV should not be more than 50° C so as not to damage the electronic equipment, which is the vehicle’s brain.

Besides Agni-V’s canisterised launch, the ASL is currently working on using decoy systems in India’s strategic missiles such as the Agni variants, which are all ballistic missiles. These decoys will be required to confuse the enemy’s anti-ballistic missile system. “It is important not only to make the missile, but to make it able to survive,” Sekaran said. “If you were to fire a strategic missile and the enemy has an anti-ballistic missile system to engage your missile, how do you overcome the hurdle and deliver your warhead?” he asked. So the ASL is working on the “theory of decoys”, which means India’s strategic missiles will be able to confuse the enemy’s radar systems, penetrate its air defence system and deliver the warhead. “We are working on this vigorously as an extension of the overall systems’ deployment to ensure that the missile survives in its journey,” said Sekaran.

On the technology front, the ASL is working on more advanced, bigger and modified rocket casings, which would be light and thereby reduce the mass of the system. This will ensure a longer range for the missile—that is, it can travel longer distances. If the mass of the rocket motor stage is reduced, its weight comes down. ASL scientists are working on a new set of composite materials to achieve a big mass fraction in rocket casings.

In the ASL, there are small groups working on designing and engineering radomes which may not be required for the Agni class of missiles but for tactical missiles. A radome normally sits in a missile’s front cone, which houses the warhead. The front cone has a terminal guidance system called the seeker. The seeker’s job is to emit electromagnetic waves, map the target and control the missile. So the front cone should be able to transmit the electromagnetic waves. This front cone, which transmits radio frequency waves, is called a radome. Normal materials such as metals will not be able to transmit the electromagnetic waves. Special materials such as composites and ceramics are needed to enable the electromagnetic waves to go out. The ASL has already made big radomes for Tejas and these have been flight-tested successfully.

Since nanotechnology goes into advanced composite structures, an ASL team is working on nanotube technology to put carbon nanotubes (CNTs) in the composites to increase the latter’s strength. The ASL has done some studies on mixing the CNTs with resin and making a composite which has a tougher structure and better properties compared to the composites where the CNTs are not inserted. “We have done studies and we got good results,” said Sekaran.

On its website, the Department of Science and Technology (DST) says the Union government had in May 2007 approved the launch of a mission on nanoscience and technology, called Nano Mission, with an allocation of Rs.1,000 crores for five years. According to the website, the Nano Mission will strive for the development of products and processes in safe drinking water, materials development, sensors’ development, precise drug delivery, and so on.

Miniaturised systems with several integration functions will become a key technology in future and the ASL is working in that area. For instance, a mobile phone of today has many integrated functions, including texting messages, receiving email, listening to music, and playing games. “Similar concepts can be applied to our missile systems,” said Sekaran.

There are two levels of work involved in this: making miniaturised systems and integrating various functions in the system. “Today, you can have four systems in a single unit and they will do different jobs. In the long run, in the automobile and aerospace industries, you will find that systems integration has become the key word,” he said. A single small unit in a missile system should have propulsion power, be able to receive telemetry signals and so on. So the volume, the mass and the complexity of wiring will come down. It will have more testability and reliability.

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