Agni-III

The Agni-III (lit. 'Fire') is an Indian intermediate-range ballistic missile inducted into service in 2011 as the successor of the Agni-II. It has a range of 3,500 kilometres (2,200 mi) and can reach targets deep inside neighbouring countries including Pakistan and China.

India's credible minimum deterrence envisaged a nuclear triad of counter-strike capability which required a long-range missile to provide robust second strike capability. India developed a larger missile, with a heavier payload and longer range in a compact configuration.

The Agni-III was developed as the successor to the Agni-II. Designed by the Defence Research and Development Organisation (DRDO), Agni-III is a two-stage ballistic missile capable of nuclear weapons delivery. DRDO formed a separate propulsion plant in September 2001 to develop large-sized solid-propellant rocket engines, including the infrastructure for propellant casting. The stubby, two-stage solid-fuel missile is compact enough for easy mobility and flexible deployment on a number of surface and sub-surface platforms.

The missile is equipped with sophisticated navigation, guidance and control systems and advanced on-board computer systems. The electronic systems are designed to withstand greater vibration, heat and noise. A high-performance, indigenous ring laser gyro-based inertial navigation system was flight-tested for the first time on 7 Feb 2010.

The two stages of Agni-III has an overall diameter of 2 metres (6 ft 7 in). Initially, The mass of first-stage is about 32 tonnes and 7.7 metres (25 ft) long, and 10 tonnes and 3.3 metres (11 ft) long for second stage. The missile was expected to support a wide range of warhead configurations, with a 4,500-kilometre (2,800 mi) range and a total payload weight of 2,490 kilograms (5,490 lb). The ground support system and launcher are developed by Research & Development Establishment (Engineers).

The circular error probable (CEP) of Agni-III is within 40 metres (130 ft). The US Air Force's National Air and Space Intelligence Center estimated that in June 2017, fewer than 10 launchers had been deployed.

The Agni-III has two solid-fuelled stages and an overall diameter of 2 metres (6 ft 7 in), compatible with an Indian sub-surface launch system which has a 2.3-metre-diameter (7.5 ft) launch-tube aperture. The first-stage booster weighs around 32 tonne and is made of advanced carbon-composite materials to provide high payload fraction (mass fraction). It is 7.7 metres (25 ft) long; the second stage weighs around 11 tonne, made of maraging steel, is 3.3 metres (11 ft) long and has vectoring nozzles for flight-trajectory control.

On 9 July 2006, the first test of the Agni-III was conducted on Abdul Kalam Island (then known as Wheeler Island), near the Bhadrak coast. The launch was unsuccessful; the missile fell into the sea off the coast of Odisha, short of the target. According to the Defence Research and Development Organisation, the failure was due to a first-stage anomaly of recirculating hot gases which entered the missile-base shroud and damaged electronic components. Indian Defence Minister Pranab Mukherjee called it a "partial success" (a euphemism indicating that the test generated useful data for diagnosis and correction), since the missile was air-borne for five minutes instead of the expected 15.