On May 4, 2017, India’s Strategic Forces Command (SFC) conducted an unsuccessful user trial of the Agni-II Intermediate Range Ballistic Missile (IRBM). This failure marks the third unsuccessful test – either development flight or user trial – of the missile and comes after a series of five consecutive successful user trials. The progenitor and successors to the Agni-II have had a reasonably trouble free development process with initial development failures being resolved and user trials meeting with success.
Agni Technology Demonstrator
The pattern was established during the testing of the original Agni missile – formerly a “re-entry demonstrator” and which we can now term the Agni-TD – which was tested on May 22, 1989. By its third test in 1994, the 2500 km range missile had achieved a demonstrated range of 1450 km with a claimed circular error probable (CEP) of 300 m. However, the most remarkable aspect of this progenitor to the Agni missiles of the 21st century was that it was a hybrid, using the liquid-fueled Prithvi-1 missile as the basis for its first stage coupled to a solid fuel booster reminiscent of, but not identical to, the booster of ISRO’s SLV-3 launch vehicle. This low-risk approach enabled India to develop an Intermediate Range Ballistic Missile (IRBM) capability at a relatively low cost, using proven technology.
In a curious twist, the Agni-II, which evolved from the Agni-TD, spawned the Agni-1. This 700-km range medium-range ballistic missile (MRBM) was borne out of an operational necessity for a missile with a longer range than the Prithvi to serve as a deterrent against Pakistan. The Agni-II was effectively re-engineered to create a smaller, lighter and road mobile system that is both survivable and easily deployable. Since its first test in 2002, Agni-1 has undergone a series of user trials from 2007 onwards, the latest being on November 22, 2016. While the missile itself is an achievement of note, the road mobile launch system should be considered of equal importance as it has evolved into the road mobile TELs for the Agni-IV and Agni-V.
At a glance, the Agni-III bears no physical resemblance to the Agni-II and is of a very different configuration, renouncing the tall, slender form for a shorter but wider arrangement. With three stages, the Agni-III represents what might be termed an intermediate stage of missile development, part way between the Agni-II and the definitive Agni-V. Once again using a rail-mobile TEL, the Agni-III represents the largest missile to date that India has fired from such a launcher.
After a failed test in 2006, the Agni-III completed a series of three consecutive successful technical trials on April 12, 2007, May 7, 2008 and February 7, 2010. Thereafter, the SFC conducted user trials of the system on September 21, 2012, December 23, 2013, April 16, 2015, with the most recent test being on April 27, 2017. Like the Agni-II, a CEP in the “two-digit” range (40m being suggested) was claimed. The Agni-III has a stated range of more than 3500 km, but it bears a striking resemblance to the Soviet-era SS-20 IRBM, suggesting the possibility that its range could be as high as 5000 km.
With a range of 4000 km, the Agni-IV represents the successor to the Agni-II. Earlier known as the Agni-II Prime, the Agni-IV is no larger than its predecessor but has a significantly greater range and, being road mobile, is even more flexible and survivable than the Agni-II. This reflects a greater use of lighter composites and improved solid-fuel propellants as well as improvements to the guidance system which ensure that even at maximum range the Agni-IV retains a “two-digit” CEP.
While its first test in December 2010 was a failure, technical trials on November 15, 2011, September 19, 2012 and January 20, 2014, the last in full user configuration, were deemed successful. Thereafter, the SFC commenced induction and carried out user trials on December 2, 2014, November 9, 2015 and most recently on January 2, 2017. It is expected that the Agni-IV will supplement and then completely replace the Agni-II in production and become the mainstay of the Indian IRBM force. It is also noteworthy that there have been persistent rumours of a canister launched version of the Agni-IV being contemplated.
The Agni-IV has been fired out to its full revealed range of 4000 km at least twice (September 19, 2012 and January 20, 2014). It was fired out to 3500 km on November 9, 2015 and for about 3000 km on November 15, 2011 and December 2, 2014.
While the first two launches of the Agni-V – on April 19, 2012 and September 15, 2013 respectively – were of the standard Indian uncanisterised missile, following the pattern set with the Agni variants I through IV, the tests on January 31, 2015 and December 26, 2016 were of a canisterised system mounted on a road mobile platform.
The Agni-V is, so far, the ultimate evolution of the Agni family. It combines the road mobility of the Agni-I and Agni-IV with the configuration of the Agni-III, but improves upon the latter in terms of redesigning the missile and making greater use of maraging steel and composite materials to make the rocket motor. Moreover, improvements in the guidance system reputedly brought down the CEP to “single-digits”. With these improvements in place, the Agni-V is now ready to enter production and induction into the SFC, which will then undertake user trials – starting with “user-assisted” trials and then, as was the case with Agni variants I through IV, conducting subsequent trials on its own.
Problems with Agni-II
In comparison to the Agni-III and Agni-IV, the Agni-II had a relatively trouble-free development flight process. On April 11, 1999, the Agni-II was tested to a range of 2300 km with a 1000 kg payload. This established a pattern for Indian missiles – production and user trials would follow three consecutive successful technical trials. The 1999 test was followed by one on January 17, 2001 and another on August 29, 2004. Production of the Agni-II followed thereafter. But it was not until 2009 that user trials began, the first two of which were complete failures due to quality control problems during manufacture. However, on May 17, 2010, the first user trial from a production batch was completed followed by similar production batch trials undertaken by the SFC on September 30, 2011, August 9, 2012, April 7, 2013 and November 9, 2014. This means that the Agni-II has become the backbone of India’s IRBM force.
The Agni-II was India’s first viable production IRBM and is mounted on a rail mobile transporter-erector-launcher (TEL) with some suggestions that the TEL can be made road mobile as well. In either case, the TEL provides Agni-II with flexibility in deployment as well as survivability. Furthermore, the system can be deployed within 15 minutes. The Agni-II marked India’s departure from liquid propellants to all solid-fuel systems. Furthermore, the Agni-II’s reputed CEP of between 30 m and 100 m at maximum range makes it a relatively accurate system.
The May 2017 test marks the third user trial failure. What is cause for some concern is that the cause of the failure seems to be very different from those in 2009 – where problems were noted at the stage separation and ignition of the second-stage phase of the launch. In the case of The May 4, 2017 test, initial reports indicate problems in the first stage itself. This could be the result of propellant problems caused by storage or even minute structural cracks in the first stage itself.
The inevitable question that arises is whether the Agni-II was rushed into production after only three technical flights. It is submitted that this is not necessarily the case.
Depending on the type of missile, technical trials are meant to establish the performance parameters of the system. Once this has been established, there is no reason why production cannot commence provided that tests from production batches are conducted to confirm performance. The development of computer simulation also helps reduce the number of dynamic technical trials which are inevitably expensive to conduct.
The Russian Federation has followed this development path, with its RS-24 and RS-26 ICBMs being placed into production after two to three successful developmental flights with the RT-2PM2 ICBM being placed on experimental combat duty after only a single test.
In the Indian context, where the production run of the Agni-II has not exceeded 36 to date, the luxury of conducting 10 or more technical trials is impractical. Moreover, given DRDO's very limited production facilities, obtaining sufficient missiles for more than 10 technical trials requires putting the missile into production.
Of greater importance must be issues concerning the production and storage of the Agni-II inventory. Given the fact that the Agni-II has been in production for the longest period of time and missiles of this type would have spent the longest time in storage, there will inevitably be cause for concern on the part of the SFC.
While it is absolutely essential for the SFC and DRDO to thoroughly investigate the causes of the failure with due consideration to such issues as quality control during production, storage, maintenance and even training of the launch crew, it is equally important not to indulge in useless self-flagellation as the Agni family has, on the whole, had a successful series of user trials extending over several variants and a number of years which should give some confidence in the robustness of the design, development, testing and induction process.