Hat-trick of hits
THE Defence Research and Development Organisation’s (DRDO) prowess in advanced software that goes into the making of interceptor missiles was proved convincingly on March 6 when a Prithvi interceptor missile achieved a direct hit-to-kill on an “enemy” missile.
“Our strength is our software,” V.K. Saraswat, Programme Director, Air Defence, DRDO, had declared in November 2008. “In the ballistic missile defence shield, if there are glitches in the software, it cannot be excused. It has to work thoroughly. There are a million lines of code. The onboard software runs in real time in the interceptor missile.”
It was the third success in a row for the DRDO, which has been making all-out efforts to acquire a two-layered ballistic missile defence shield with interceptors that can shoot down incoming missiles. It tasted success in its first mission on November 27, 2006, when a Prithvi missile intercepted a Prithvi-II missile at an altitude of 48 km in what is called the exo-atmosphere. It was a direct hit. The interceptor was called Prithvi Air Defence (PAD-01). Again, on December 6, 2008, an Advanced Air Defence (AAD) missile shot down a modified Prithvi missile at an altitude of 15 km in what is called the endo-atmosphere when the “attacker” was in the final stage of its flight. It was a direct hit too. With the March 6 direct hit, the DRDO has achieved a hat-trick.
Three features stood out in the latest mission: the Prithvi interceptor missile’s gimballed/manoeuvrable warhead, which can rotate 360 degrees; the interceptor’s coasting phase, which can “take care” of the manoeuvres performed by the attacker; and the very advanced software residing in the computers of the interceptor. The warhead is called a directional one because it can be directed to explode towards the target. Only the U.S. and Russia have gimballed directional warheads.
The highlights of the mission were proving the technology of the gimballed directional warhead and demonstrating the interceptor’s coasting phase, using a vernier thruster. This coasting phase in the interceptor’s trajectory helps it to decide at what stage it should intercept the “enemy” missile. If the attacker does a manoeuvre, the interceptor’s guidance system will take care of it. To make the seeker effective, the DRDO used a wide-beam RPF in the warhead, which was a mini-radar. “So even if there is a manoeuvre by the enemy missile in the last 500 milliseconds, the RPF will be able to take care of it. The directional warhead will be ignited on the basis of the data given by the RPF,” said Saraswat.
