India has tested the longer range version of its Prithvi II ballistic missile, this one successfully hitting a target 350 kilometers away. This launch was to test the ability of the missile to carry a half ton warhead. This is the minimum size for a nuclear warhead. India will take 5-10 years to develop the miniaturized warheads Russia and the United States developed in the 50s and 60s.
A larger, 5.6 ton, Prithvi III is in development. This missile can carry a half ton warhead 600 kilometers. Ten years ago, the best a Prithvi II could do was 250 kilometers with a quarter ton warhead. The increase in range and warhead weight for the Prithvi III was achieved by using a solid fuel rocket motor, and adding a second stage with a liquid fuel motor.
Prithvi missiles are used, in slightly different versions, by the army and air force. The basic army version has a range of 150 kilometers (and a one ton warhead), while the air force versions can go 250 kilometers (with a half ton warhead). The Prithvi is a ballistic missile that reaches its target within 5-10 minutes of launch. The missile uses liquid fuel, meaning it takes up to an hour to ready for launch. Over a hundred missiles have been delivered so far, with all the recent production being the 250 kilometer version.
At least three missile units (called groups) have been formed, each with 12 mobile launchers and at least two dozen missiles. The Prithvi missile carries cluster bomb and nuclear warheads. Accuracy is thought to be quite good, using software correction and GPS to achieve under fifty meter accuracy. The missile, with non-nuclear warheads, would be used against high value targets like headquarters or fuel and ammo depots. Test firing of the Prithvi are held regularly, for training and quality control purposes.
The original Prithvi missile was 23 feet (7.5 meters, 8.5 meters with some larger warhead), has a circumference of 9.3 feet (3 meters), and weighed 3.5 tons (4.1 tons with larger warheads). With the "standard" 550 pound warhead, range was 250 kilometers. A one ton warhead reduced range to about 80 kilometers. There are six conventional warheads available: high-explosive/fragmentation, anti-personnel/vehicle submunitions, incendiary submunitions, runway cratering munitions, FAE (Fuel-Air Explosive) and earth-penetrating bunker buster.