Ending worldwide speculation about the futuristic Agni-6 missile, the Defence R&D Organisation (DRDO) has briefed about the direction of India's ballistic missile development programme after the Agni-5 enters service, probably in 2015.

DRDO chief Dr VK Saraswat, and missile programme chief Dr Avinash Chander, say the Agni-6 project has not been formally sanctioned. However, the missile's specifications and capabilities have been decided and development is proceeding apace. Once the ongoing Agni-5 programme concludes flight-testing, the defence ministry (MoD) will formally okay the Agni-6 programme and allocate funding.

Chander says the Agni-6 will carry a massive three-tonne warhead, thrice the weight of the one-tonne warhead that Agni missiles have carried so far. This will allow each Agni-6 missile to launch several nuclear warheads -Multiple Independently Targetable Re-entry Warheads (MIRVs) - with each warhead striking a different target. Each warhead - called Maneuverable Reentry Vehicle (MARV) - performs evasive maneuvers while hurtling down towards its target, confusing enemy air defence missiles that are trying to destroy them mid-air.

The DRDO is at an advanced stage of developing these warhead technologies. But the difficult challenge is building a booster rocket that can propel a three-tonne payload to targets 5000 kilometres away. This weighs almost as much as the satellite payload carried by the Indian Space Research Organisation's much larger and heavier Global Satellite Launch Vehicle (GSLV).

"Our ballistic missiles must be compact and road mobile, even the Agni-6 with its heavy payload. We will do this by building the first stage with composites, fitting the Agni-6 with India's first composite 40-tonne rocket motor. This is a technical challenge but we have good capability in lightweight composites," says Chander