Agni missiles are a family of intermediate- and long-range ballistic missiles developed by India under Integrated Guided Missile Development Programme (IGMDP). An inter-continental ballistic missile (ICBM) is a ballistic missile with a range of more than 5,500 kilometers (3,400 mi) while an intermediate-range ballistic missile (IRBM) is a ballistic missile with a range of 3,000–5,000 km (1,865–3,100 miles). India started its quest for a declared IRBM capability with the birth of the IGMDP on July 22nd 1983 and the Agni program started along with it. The first technology demonstrator version of the Agni missile was tested in 1989 from the interim test range at Chandipur on sea in Orissa. The Agni-I and the Agni-II are the two versions of this missile that have currently been operationally deployed by the armed forces in a declared capacity with maximum declared ranges of 750Km and 3000Km respectively. The Agni-I is operational with the 334 Missile group at Secunderabad while the Agni-II is operational with the 335 Missile Group also at Secunderabad.
The program was further expanded to include two new Agni Missiles called the Agni-III and the Agni-V in the late 2000’s. The first successful test of the Agni-III missile took place on the 12th of April 2007 with subsequent successful tests on the 7th of May 2008 and February 7th 2010, and subsequently the missile was declared successfully inducted into the armed forces on June 2011 and a missile group is currently being raised to utilize these missiles. The Strategic Forces Command (SFC) has also conducted a successful user test of the Agni-III with the test of an operational SFC missile on the 21st of September 2012. The Agni-V missile for its part was first tested on 19th April 2012 and was declared to be an ICBM with a maximum range of 5,800Km.
With this context let's move on to more interesting aspect of Agni missiles Agni-III and Agni-V where I have compared them to contemporary intermediate-range ballistic missiles (IRBMs) and long-range ballistic missile (LRBMs) in the Table 1 and ICBMs in Table 2.
If you notice carefully, you can see how the Agni-III IRBM and Agni-V LRBM seem to be much larger and heavier than any of their contemporaries around the world, which indicates that these missiles carry far more fuel than what is declared pointing towards a potential for far greater ranges. Take for example, a comparably modern Chinese DF-21 road mobile IRBM carries only 14,700Kg of fuel compared to the Agni-III’s 48,000Kg while achieving the same range. Similarly, an Israeli Jericho-II IRBM carries nearly 20,000Kg less fuel while matching the range of an Agni-III. Up on further comparison, one can clearly see that all of the contemporary IRBMs and LRBMs deployed in the world today have comparable characteristics except for the Agni missiles that seem to stick out as a sore thumb (please note that Agni-III or V are not compared to the Pakistani Missiles because there is no equivalent Pakistani ballistic missile). The Agni missiles carry a lot more fuel and are bigger than their peers (please note that for determining range correctly we also have to factor in the warhead weight and type of propellant used, here it is assumed that the propellant used in the Agni missiles must be at least as developed as the one used by the DF-21 or the Jericho. Also the warhead weight is derived from open sources only). All said and done, the Agni series of missiles still look to be quite unique in this segment which leads us to the assumption that there is more to the Agni missile than what meets the eye.
To strengthen this point further, here is a comparison of the Agni missiles with full fledged ICBM’s from around the world in Table 2.
The Agni series of missiles fits in perfectly with these ICBM missiles group, the difference being that these missiles are with far more range and capability than the declared intent of the Agni missiles. In this ICBM group, we have the Minuteman III a 13,000Km range monster that is today the mainstay of the American land based strategic missile systems, the TOPOL-M an 11,000Km beast that fulfils the same task for the Russians and the long arm of the Chinese military the DF-41 rounds off the trio with a reported range of 14,000Km. Going through the ICBM comparison chart, one can see that even in this group the Agni missiles are the heaviest when it comes to total weight at launch but the shortest when it comes to range. Now the only factor that stands out as restricting the range of the Agni missiles is the warhead weight, the Agni-III has by far the heaviest warhead of the group weighing in at a whopping 2500 Kgs compared to the more sedate 1500 Kgs of its sibling that compares very favorably with the “Big Boys”. However, this weight is that of a conventional warhead filled with high explosives but with a Nuclear warhead this should be much lower. If we assume that the Indian Nuclear weapons program is at least as developed as the American program was in the eighties (assuming a thirty year lead on India) India should still be able to build warheads such as the W71, W62 (with mark-12 reentry vehicle) and W85 which respectively weigh 1290kg, 500Kg and 400kg. These facts points to the assumption that the payload is going to be a lot lighter for an Agni missile even with three Multiple independently targetable reentry vehicle (MIRV) warheads of the W62 category with approximately the same kind of reentry vehicle.
Another factor that could come into play for the reduced range (however unlikely) is that the Agni missiles have incredibly inefficient engines that burn fuel at twice the rate of its contemporary missiles. However, in such a case the velocity of the missile should be a lot more than its contemporaries as well to compensate for the much larger quantity of exhaust gases and thus increased thrust of the engine. Even in such a case we see that, as per the publicly available reported statistics of the first Agni-V test in April 2012, the missile is believed to have travelled 5000 Km approximately in a span of 1130 seconds i.e. achieving an average velocity of 4.24km/sec or around 13 Mach (disputable since the Agni-V flies at an altitude of 100Km and velocity of sound taken is at sea level). News reports also indicate that the Agni-V attained a velocity of up to 7,000 m/sec or around 20.5mach similar to that of Chinese DF-41 which has an average velocity of 10-25 Mach as well which also corresponds to the average velocity of all well-known Missiles. And therefore it is not the engines either which is responsible for such large size.
I believe that for once shrewd and prudent decisions have been taken in our Ministry of Defence and what we have in the Agni-III and Agni-V are quite possibly full-fledged ICBMs masquerading as IRBMs.
Note: All information used in this analysis has come from open sources. Also the exact thickness of the missile cylinder is unknown for all cases. I have also assumed that almost the entire launch weight shall be the fuel weight.
Disclaimer: Opinions expressed in the article are personal opinions of the author.