DRDO Anti Tank Missile

The DRDO Anti-tank missile (ATM) is a first generation wire-guided missile developed in India by Defense Research & Development Laboratory (DRDL) of Defence Research and Development Organisation (DRDO). It has a subsonic speed up to 300 ft/s with a range of 1.6 km and carries a 106 mm HEAT warhead.

Introduction
In 1959, India started a feasibility study on a First Generation Anti Tank Missile (ATM). New General Staff Qualitative Requirements (GSQR) were issued and the task of preliminary study and wind testing was assigned to Department of Aeronautics and Institute of Science, Bangalore.

Development
In 1962, DRDO was granted 600,000 Indian Rupees to begin work on developing an Anti-Tank missile due to conflict with China in Ladakh. It has a range of 500 meters to about 4 km.

After the first aerodynamic design was completed, a full scale model of the complete configuration was tested in a wind tunnel at IISc Bangalore. At Banglore, this model was tested for the force and momentum tests which were completed in 1961. Vibrating spoilers were used during these tests to determine control effectiveness. The ATM was designed to have a subsonic flight speed of about 300 ft/s (90 m/s). In 1963, the entire design was reworked for accommodating 106 mm HEAT warheads in the ATM.

Propulsion
Defense Research and Development Laboratory (DRDL), a DRDO lab, determined the propulsion motor requirement and designed the propulsion system. The propulsion motor was made of aluminium alloy. It had two compartments, one for the sustainer and the other for the booster.

Explosives Research & Development Laboratory (ERDL), another DRDO laboratory, made the propellant compositions and also developed the SUK black propulsion grains. Molybdenum inserts were used as sustainer. The booster grain had star type hole for very fast burn and the sustainer was cigarette burning type for constant thrust.

Control & Guidance
The actuator and gyroscope were the main components of the control and guidance system of the ATM. The Actuators were spoiler type, (similar to Mosquito (missile)), which gave a response time of 10 millisecond with a stay time varying from 80-20 and 20-80 milliseconds. The gyroscope developed for the ATM was a three degree freedom gyroscope.

Testing
The missile was test-fired near Imarat, a village on the outskirts of Hyderabad, which held the reliability order of 65%. The test trials were attended by Gen Bewoor, then Deputy Chief of Army Staff of the Indian Army. The missile was tested 16 times and hit its target 14 times. Two Indian army teams which were trained on European ATMs, Cobra and ENTAC, carried out the tests. These test did not reveal any significant difference between firing the European and indigenous ATMs. Work was still to be done on inhibition of the sustainer motor.

Short Closed
In 1969 ATM project was terminated as the Indian Army revised its General Staff Qualitative Requirements (GSQR). The new GSQR extended the range of the missile from 1.6 km to 3 km. They also required the previously man-portable missile to be capable of being mounted and fired from a mobile-launcher. This led to production of SS11B1 at Bharat Dynamics Limited (BDL), Hyderabad under license from France.

Future Development
Nag missile