There was scepticism on November 27, 2006, when the Ministry of Defence made a surprise announcement. In a secret test off the Orissa coast, a missile launched by the Defence Research and Development Organisation had hit and destroyed a simulated incoming enemy ballistic missile while it was 78 km above the Bay of Bengal, still outside the earth's atmosphere.

A year later, on December 6, 2007, the MoD declared a second test successful, when an incoming ballistic missile was shot down inside the atmosphere, some 15 km above the earth. This was high-technology success; no more than six or seven countries have anti-ballistic missile capability.

Unlike the shrill promises that accompanied the Trishul and Akash anti-aircraft missiles, the ABM programme was kept secret, even from close watchers of the DRDO.

Business Standard was granted exclusive access to the ABM missile production facilities in Hyderabad, and told the story of how the programme evolved.

It began in 1995, after India learned that Pakistan had obtained the M-9 and M-11 ballistic missiles from China. India already had its own nuclear deterrent in place; the Prithvi missile was ready, and the Agni was being tested.

But Pakistan was considered unpredictable and, in 1996, the MoD asked its Scientific Advisor APJ Abdul Kalam [Images] whether India could quickly develop protection against an incoming Pakistani ballistic missile.

Kalam was already overseeing the Integrated Guided Missile Development Programme; he began feasibility studies on an ABM programme as well. DRDO's first challenge was to develop radar, which could pick up enemy ballistic missiles being launched from up to 300 km away.

The longest range Indian radar was Rajendra, with a range of 60 km, and there simply was no time to develop long-range radar from scratch. The only option was foreign collaboration. Kalam put one of his top scientists, VK Saraswat, in charge.

Saraswat recounts Russia [Images] was approached first, but the conditions in Russia -- with defence R&D at an all time low -- made the DRDO reject that option. It was then that the Israeli ABM programme -- the Arrow-1, based upon the long-range Green Pine radar --caught the DRDO's eye.

A delegation was sent to Israel, but it was turned down because the Green Pine radar incorporated US technology. But Israel did agree to collaborate with India in building a Long Range Tracking Radar.

Also needed for the system was guidance radar to track the incoming enemy missile. The Electronics and Radar Development Establishment (a DRDO laboratory), explains Saraswat, has developed that radar in collaboration with a French company, Thales.

With the radar problems solved, government sanction was obtained in 1998 to develop an ABM system; the ability to defend against an enemy nuclear strike is believed to undermine deterrence.

But the project remained secret, because an ABM system is controversial. Besides that, says Saraswat, India's nuclear tests that year had tightened international sanctions.

"We were having collaboration with these two countries, but the times were not good. We faced severe sanctions in 1998 and, if we talked too much about it, the cooperation could have dried up. That was the main concern."

But while the radars were a collaborative effort, interceptor missiles were developed entirely by the DRDO, say the scientists. So were the mission control centre and the launch control centre, which are the nerve centre of the system.

The DRDO says the programme has now reached maturity, and that international sanctions cannot hurt it. There is also a degree of self-confidence in the DRDO, which allows it to acknowledge the role played by other countries. International collaboration is no longer a bad word.