T-90S Bhishma Tank during Republic Day Parade 2009
The T-90s - renamed Bhishma after the Mahabharat patriarch - is successor to the T-72 tanks in the Indian Army.
Initial plans envisaged induction of 1,657 T-90S tanks, with 1,000 of them being manufactured locally under license.
The T-90S Bhishma is a 46.5-ton main battle tank (MBT) powered by a 1,000 HP engine.
Regarded as one of the most lethal MBTs in the world, the T-90S is vaunted for its mobility, lethal firepower and first hit ability during engagements.
The tank is equipped with a 125mm smooth bore gun stabilized in Elevation and Azimuth that is capable of firing all types of ammunition including laser guided missiles to a range of 5 km. The gun has an Automatic Loader ensuring high rate of fire.
The tanks additionally has a 12.7mm anti-craft machine gun and 7.62mm co-axial machine gun supported with high accuracy sighting systems.
Capable of night fighting, the tank is equipped with night vision devices and thermal imaging system. It can see upto 4 kms passively in the dark.
It is protected by Explosive Reactive Armor (ERA) and an Active Protection System (APS) capable of intercepting projectiles directed at the tanks from all direction using soft and hard kill techniques.
The initial order placed on Russia in 2001 was for 310 T-90S tanks to India - 120 in ready to use condition, 90 as semi-knocked down kits and 100 in completely knocked down kits.
Simultaneously, Russia was to supply documentation and other know-how for the local manufacture of the tank in India.
The first assembled T-90S tank ‘Bhishma’ rolled out of the assembly line in the Heavy Vehicles Factory (HVF) at Avadi, Tamil Nadu on January 7, 2004.
The HVF was to make 100 T-90 tanks annually over the next 10 years but took time to absorb the technology transferred from Russia and setup local manufacture.
The first batch of locally manufactured Bhishma rolled out in August 2009.
In October 2006 MOD ordered additional 330 improved T-90M Bhishma developed by HVF with assistance from Uralvagonavod, Thales which supplied its Catherine-FC thermal sights and other companies.
A follow-up order for 347 T-90Ms was placed in December 2007.
On November 4, 2012, The Tribune reported that the Indian Army had placed an order for 236 upgraded T-90 tanks featuring some of the electronics used on the T-90MS tank displayed at DefExpo 2012.
The new features will give the tank improved first fire capability with automatic tracking of targets.
Automatic tracking of targets allows the tank gunner to "lock-on" a target once and then let the computer track it, instead of manually tracking it, which is a difficult task when dealing with a moving target while in a moving tank.
After the gunner locks on to a target, on board optics and electronic fitted on the tank will continuously track the target in a 360 deg arc, factoring in distance of target, height and temperature of the barrel to automatically correct the line and trajectory of fire.
The upgraded tanks will additionally feature a new muzzle reference system. At present, the front muzzle on the barrel of the tank needs to be aligned afresh each time the barrel position is lowered. The latest version of the T-90 will have a system by which the tank barrel will re-align itself to its earlier-programmed reference point, sources explained.
An improved thermal imager capable of sensing variations in temperatures of an advancing vehicle or human being will improve situational awareness of the tank-commander. Existing thermal imagers do not detect variations in temperature.
The imager will able to generate sharp images at nighttime from a distance of 3-4 km.
The tank's engine and traction remain unchanged.
The upgraded tanks will be produced at Heavy Vehicle Factory (HVF) at Avadi and work on the project is already underway.
Army has no plans to retrofit the upgrade on its existing fleet of T-90 tanks equipping 20 regiments.
As in April 2012, the Indian Army has about 450 tanks in service with another 300 on order.
The army plans to field 1,640 T-90s by 2020.