Tuesday, December 18, 2007

DRDO’s Advanced Air Defence missile - A Smashing hit

The DRDO’s Advanced Air Defence missile propels India into a select group of countries with the ability to intercept ballistic missiles.

The Advanced Air Defence interceptor missile taking off from Wheeler Island.

THERE was applause at first, followed by five minutes of silence as missile technologists of the Defence Research and Development Organisation (DRDO) scanned the consoles in front of them. After 25 seconds of tension, a deafening applause broke out in the Mission Control Centre (MCC) on Wheeler Island, 17 kilometres from Dhamra on the Orissa coast. The atmosphere turned electric as the young men and women missile technologists went delirious with joy. Full-throated cries of “DRDO zindabad”, “Three cheers to DRDO” and “Hip, hip hooray” filled the room as vigorous handshaking and warm hugs added to the celebratory mood. “Gentlemen,” announced V.K. Saraswat, Mission Director, “many nations have done the interception in exo-atmosphere [between 40 km and 75 km above the earth]. But a direct hit in endo-atmosphere [at an altitude of 15 km to 30 km] is something fantastic. It is unbelievable…. It is phenomenal.”

On December 6, 2007, when the DRDO’s interceptor missile called Advanced Air Defence (AAD-02) scored a direct hit on an incoming, modified Prithvi missile, it propelled India into a select group of three countries with the ability to intercept ballistic missiles. The countries that already have this capability are the United States, Russia and Israel. According to Saraswat, the modified Prithvi missile that played the role of attacker “mimicked” the trajectory of M-9 and M-11 ballistic missiles, “which are with our adversaries”.

The sequence of events was as follows. At 11 a.m. the single-stage “attacker” Prithvi missile lifted off from its mobile launcher (a Tatra truck) in Launch Complex III at the Integrated Test Range (ITR) at Chandipur, near Balasore, Orissa. At once, radars at Konark and Paradip, both in Orissa, swung into action, located the target missile while it was climbing and communicated information about its velocity and position in real time to the MCC. The MCC, in turn, classified the target missile as a ballistic missile and assigned the task of intercepting it to the AAD-02 launcher battery located on Wheeler Island, 70 km across the sea from Chandipur. The MCC quickly calculated the trajectory of the incoming missile and where it would impact. This information was conveyed from the MCC to the AAD-02 launcher battery through a mobile communication terminal, which is a bank of sophisticated computers located on a massive truck.

After the attacker missile reached its apogee of 110 km, the command for the interceptor, AAD-02, to lift off was given. The interceptor erupted into life five minutes after the attacker lifted off. The interceptor was equipped with inertial navigation, control and guidance systems. More importantly, it had on board a radio-frequency seeker. Acting as the “eye” of the interceptor, the seeker calculated the velocity, position and direction of the “enemy” missile. The seeker conveyed all this information to the computers on board the interceptor, and the computers instructed the interceptor to manoeuvre itself towards the target. And before one had time to clap, the AAD-02 homed in on the target and made a direct hit at an altitude of 15 km. The attacker was shot down during the terminal stage of its flight. The interception took place when the target missile was in free fall at a speed of about Mach 3 (that is, three times the speed of sound) and the interceptor was travelling at more than Mach 4.

An ecstatic Saraswat, who is Chief Controller, DRDO R&D (Missiles and Strategic Systems), called the mission “a dream come true”. He said: “The data received in real time from the radars demonstrated the formation of a large number of tracks, signifying that the target had broken into multiple pieces and that the debris was tracked by the radars. The thermal cameras located on Wheeler Island also picked up the direct hit through thermal images. The achievement of a direct hit against a high-speed target demonstrates the capability of the AAD missile system to intercept targets up to a range of 2,000 km. It also signifies the development of complex guidance, control, navigation and propulsion systems; radars, seekers, computer, command, control and communication systems; robust communication networking; software development; and so on.”

Saraswat summed up the significance of the mission thus: “The successful interception certainly confirms the capability of India to defend itself against incoming ballistic missiles. We can assure the nation today that the DRDO has the technology to develop a potent missile shield for the country.”


M. Natarajan, Scientific Adviser to the Defence Minister, compared the interception to “hitting a bullet with another bullet” and attributed the success of the mission to the “pioneering work” done by young DRDO professionals. Natarajan, who is also Secretary and Director General, DRDO R&D, watched the lift-off of both the target and attacker missiles and the interception live on a video link provided at DRDO Bhavan, New Delhi.

Avinash Chander, Director, Advanced Systems Laboratory (ASL), Hyderabad, described it as “a tremendous mission and a tremendous moment”. He added: “What we have achieved today is something unheard of. I don’t think any country has been able to launch a missile and hit it the first time…. The interceptor crossed the target missile at the correct point. The target missile went into fragments thereafter.”

The target missile was a modified, single-stage Prithvi, fuelled by liquid propellants. To suit the requirements of this mission, the control system of Prithvi was modified so that it could reach an altitude of more than 100 km. The modified Prithvi was 11 metres tall and weighed five tonnes. Its diameter was 1 m. Its launch, in this instance, was carried out in an independent manner by the Army, which already has Prithvi-I and Prithvi-II missiles. The interceptor was, however, “a totally new missile”, 7.5 m tall, weighing 1.3 tonnes and with a diameter of 0.5 m. It was fuelled by solid propellants.

While Saraswat was the Mission Director at Wheeler Island for the interceptor missile, D.S. Reddy was the Vehicle Director. For the “attacker” missile, Lieutenant General (retired) V.J. Sundaram was Mission Director-Coordinator.

The successful interception confirms that India has taken the first few decisive steps forward on the road to acquiring a ballistic missile defence shield. The interception in the endo-atmosphere was carried out as part of the DRDO’s quest to build a two-tiered ballistic missile defence shield. On November 27, 2006, India’s interceptor missile called Prithvi Air Defence (PAD) intercepted an incoming Prithvi-II missile at an altitude of 50 km. That was also a direct hit.

On December 2, 2007, AAD-01 intercepted a simulated electronic missile at an altitude of 15 km above the Bay of Bengal. The electronic missile was launched from Chandipur and the interceptor from Wheeler Island. That is, electronic signals that mimicked the trajectory of an enemy ballistic missile were sent. And the interceptor, which was a real missile, took off, manoeuvred itself close to the electronic trajectory and extinguished the “enemy missile” by “proximity killing” (as opposed to a “hit to kill” or a direct hit).


Informed sources warned that although these two tests, in the exo-atmosphere and the endo-atmosphere, were successful, what India had today “is only an essential module for a possible ballistic missile shield” and that it would take several more tests for India to have a credible ballistic missile defence shield.

Although Israeli and French radars were used in the mission on December 6, what was amazing was the highly sophisticated software developed by DRDO’s young software professionals. Natarajan, who took pains to emphasise the importance of the high-end software developed by the DRDO’s young team, said, “This is hard core engineering-related software, not BPO [business process outsourcing] software. It shows the significant capability of networking massive software linked to hardware actuation.… If you can do this for a missile, you can do it for civil aviation.”

Saraswat, who traced the evolution of these two interceptor missions, said they began as a concept in 1997 when A.P.J. Abdul Kalam (then DRDO chief and Scientific Adviser to the Defence Minister) asked whether it would be possible to intercept a Prithvi missile with an Akash missile (while Prithvi is a surface-to-surface missile, Akash is a surface-to-air missile).

The project itself began in 1998. There were discussions as to whether Akash could be modified, but it was decided that Akash would not do as an interceptor. After the radars were chosen, the interceptor had to be configured. Marathon discussions took place on whether the interceptor should be fashioned out of Prithvi or Agni-1.

“The whole process was difficult because the technologies were complex, starting from the choice of radars,” Saraswat said. It was a difficult journey setting up the radar stations, indigenising the radars, developing the mission control software, and so on.


“Imagine, if we did not have the radars, we would not have known that the actual interception had taken place,” he said.

Several DRDO units and private industries contributed to the mission. The Defence Research and Development Laboratory (DRDL) in Hyderabad provided the mission control software. The Research Centre, Imarat (RCI), Hyderabad, another DRDO unit, provided the navigation, electromechanical actuation systems, the seeker on board the interceptor, and so on, all of which ensured the direct hit. The ASL provided the motors, jet vanes and structures for the two missiles.

The High Energy Materials Research Laboratory (HEMRL), Pune, also a part of the DRDO, supplied the propellants for the missiles. The ITR at Chandipur and Wheeler Island, headed by S.P. Dash, its Director, provided the range. Saraswat praised the ITR for the quality of its instrumentation. Programme Air Defence carried out the configuration of the AAD-02 missile. Indian Air Force personnel did a marvellous job of manning the radars. Several private industries, such as L & T and Vem Technologies Private Limited, Hyderabad, also made important contributions to the mission.

The DRDO has now set its sights higher. It wants to take up “the harder challenges” of engaging an Intermediate Range Ballistic Missile (IRBM), launching two missiles in the exo-atmosphere and the endo-atmosphere against a single target missile, and so on. A happy Saraswat asserted, “Today, the DRDO is in a mission mode with Agni-III, Air Defence, Astra and is preparing for the short-range surface-to-air missile, which is in the conceptual stage, that can be used by all the three services. In this, we have not included the on-going programmes such as BrahMos, Akash and Nag.”

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