S -400: The Game Changer

Sub Title : S-400 Triumf Air and Missile Defence System will bolster our air defence capabilities

Issues Details : Vol 14 Issue 3 Jul – Aug 2020

Author : Lt Gen Vk Saxena, PVSM, AVSM, VSM (Retd)

Page No. : 31

Category : Military Technology

: July 28, 2020

India is acquiring the S-400 Triumf Air and Missile Defence System to bolster its capabilities. The article is a lucid exposition of how the need for such a system came about, the characteristics thereof and the huge advantage that will accrue once it is inducted. It is indeed going to be a Game Changer

The S-400 will be a ‘game-changer’ is the buzzword today. The weapon system was also one of the agenda points during the recent visit of the Defence Minister to Russia on 22 Jun where he asked for its speedy and timely delivery. This article attempts to explain how the need for this system evolved over time and what would be the place of this weapon system in the larger perspective of air and missile defence at the national level.

What is S-400?

S-400 is an air defence and missile defence system. By this definition, it performs two roles.

  • A counter to aerial threats. The threats are posed by multiple air threat vehicles consisting of multi-role aircrafts (some with stealth features), attack helicopters (AHs) and unmanned aerial systems (UAS) firing a complete arsenal of rockets missiles, bombs, precision guided munitions (PGMs), smart and intelligent arsenal and soft-kill weapons. In addition, there are cruise missiles, Anti-Radiation missiles (ARMs) and more, to complete the punch.
  • A counter to Ballistic Missiles. Pakistan has ballistic missiles with ranges from 80-2950 km and China has ballistic missiles covering ranges from 550km to 14,000+ km. While all these missiles can carry conventional ammunition, several of these are also nuclear capable. The S400 can defeat a ballistic missile threat adequately.

Evolution of Air Defence

Given below is a summation of how the air defence of the country has evolved leading to the need for a strategic system like S-400  .

There was a time in mid-sixties/early seventies when aerial threats were binary viz aircrafts and helicopters. These two could operate only in fair-weather and could fire front guns, unguided bombs and rockets in the visual domain (about 2-5 km) only. The assets (vulnerable areas/points or VAs/VPs) to be guarded against the above threats were finite. It was therefore considered adequate to deploy anti-aircraft (AA) guns around VAs/VPs in single and multiple rings based on the criticality of the asset to ward off the air threat. Since then the following has happened:-

  • Air threats have grown multi-fold, wherein, the erstwhile duo of aircrafts and helicopters have metamorphosed into deadly combination of aircrafts capable of deep strikes with precision and stand-off capability and attack helicopters (AHs) capable of flying the-nap-of-earth and preying on their targets with needle-sharp precision.
  • To add to this are the ‘dull, dirty and dangerous’ Unmanned Aerial Systems (UAS) either operating alone or with manned platforms in joint Manned and Unmanned Teaming ( MUM-T) missions or in deadly multiple swarms unstoppable by conventional air defences.
  • Cruise missiles have come up with sub-meter accuracies taking on precision kills while the deadly ARMs, Beyond Visual Range (BVR) missiles and more have added to the lethality of the air punch and the range and reach of ballistic missiles has increased.
  • Number of VAs/VPs has so grown that it is impossible to protect each one of them.

Bound to the eternal cause-effect cycle, while air threats got revamped, the defenders’ shield also got adequately empowered riding on the enabling wings of technology.

  • The impossibility as well as, the futility of the old practice of defending each VA/VP by some fair weather AA guns was established as early as late seventies.
  • It was realised that instead of protecting each VA/VP, there is a requirement to extend air defence cover over geographical areas which contain many VAs/VPs .
  • This pattern of deployment on a theatre grid pattern was executed by different Ground Based Air Defence Weapon Systems (GBADWS) extending from visual domain to far off ranges.
  • This weapons consisted of fair-weather and all-weather capable guns (range 3-5 kms) Very Short Range AD Systems or VSHORADs (range 6-10 kms), Short, Medium and Long Range Surface to Air Missiles (SRSAM, MRSAMs and LRSAMs) covering range brackets of 20-30km, 60-100km and beyond 100 kms.
  • Such a long ‘fire-arm’ was needed because it was realised that to take on a multi-platform air threat as described above, the threat vehicles had to be identified as far forward as possible and subjected to ‘successive’ punishment in a ‘seamless’ manner. To create sufficient density of fire all along, GBADWS were deployed in overlapping rings.
  • Such deployments taken along with their Battle Management and Control (BMC2) system was called layered and tired pattern of defence.
  • Such defences duly integrated on land sea and air formed the Integrated Air Defence System (IADS) at the national level.

Why is Ballistic Missile Defence required?

It is in this IADS that voids were becoming apparent basis the growing threats, especially the missile threat for which  BMD systems became a necessity. Following was the flow of events.

  • Taking due note of the growing missile arsenal of Pakistan and China, a need was envisaged, sometime in 1999-2000, of fielding a dedicated Ballistic Missile Defence (BMD) System.
  • Various options ex-import were considered (ANTEY 2500 (75 km)-Russia, S-300/PMU (100-400km)- Russia, Patriot (87 km) – USA, THAAD (200 km)-USA and AEGIS BMD- USA
  • However, based on assurances given by the DRDO, it was decided at the highest level to go in for indigenous BMD capability.
  • Accordingly, an in-house BMD development programme codenamed ‘Programme AD’ was launched in 2000. The Programme aimed at developing BMD capability in two phases. In Phase 1, which was to be completed by 2012, a capability to take on the enemy’s ballistic missiles up to 2000 km was to be developed, and in Phase 2, which was to be completed by 2016 this capability was to be extended to take on enemy’s ballistic missiles up to 5000 km.
  • Both the phases stand completed. Details being classified are not being discussed.

While all this was happening on one track, on the other, the missile threat from our potential adversaries was rising at a fast pace. Somewhere around 2013-14, when Programme AD was inching forward towards completion of its Phase 2, following became clear to the decision makers.

  • Programme AD BMD capability was too small commensurate to our national strategic assets, which include nuclear establishments, core sector critical infrastructure and strategic war-waging reserves etc. The time that the programme would take to reach matching levels was also not deemed suitable.
  • An urgent operational need was therefore felt to boost our BMD capability.

The Process

The process of acquisition is enumerated below.

  • During Prime Minister Modi’s Dec 2015 visit to Russia the requirement of BMD capability for India was discussed with the Russian President. And at that time the offer of S-400 was formally made.
  • The Defence Acquisition Council (DAC) on 17 Dec 2015 approved the Acceptance of Necessity (AoN) for the import of 5 regiments of S-400 air defence and anti-missile system at a cost of USD 5.43 Bn.
  • In Mar 2016 there was an open source report from Russia talking about the Inter-Govt Agreement (IGA) for the export of 5 regiments of S 400 to India.
  • In May 2016, the then Defence Minister confirmed the Government’s intention of going ahead with the above deal despite US pressure and finally, during the BRICS summit in Oct 2016, the contract for 5 Regiments of S 400 was inked.
  • The initial time frame agreed was for starting the supply of the first regiment after 36 months and completing all the five regiments within 4 years ( 2020-2024).

The Technical Muscle

The game-changer tag given to S-400 is pinned to the technical muscle of the system. The development of this series of weapon systems started in the erstwhile Soviet Union sometime in 1978-79. At that time, the weapon was being developed as an area air defence missile system capable of providing air defence and anti-missile protection to large-sized VAs, military bases, industrial centres and logistic support areas.

In the period from 1978-2016 (that also saw the demise of Soviet Union and taking over of its legacy by Russia), three verticals of this class of weapons were developed. The ‘P’ Series (or PVO Stranny meaning country’s air defence system) were the mainstream systems having ranges from 200-250-300 and 400 km (S-300P/PT/PM-1/PMU-1/2/3, S-400). ‘V’ series was the version of the systems meant for mechanised forces (S-300V/V1/V2) while the ‘F’ series was for naval applications (S-300 F/FM/FORT/FORTM).

Any weapon of this class stands on its three verticals, namely ‘sensors’, ‘shooter’ and ‘BMC2.’ A few words on these related to S 400.

In the parlance of the BMD systems the sensors stand in two classes. Firstly, Long Rage Surveillance Radars (LRSRs) whose job is to detect the threat from ballistic missiles at longest possible ranges and Multi-Function Radars (MFRs) whose job is to direct own missiles on the chosen targets transferred to them by LRSRs.

The Shooters are the teeth or the interceptor missiles and the BMC2 system has the role of controlling the resources of the system and ensuring the smooth flow of engagement.

In each of the above three verticals S-400 is special. Brief details of sensors are enumerated below.

  • When the system was in its development years, there were three separate LRSRs, one optimised for medium and high altitude detection (36 D6), one optimised for low level detection (76N6) and one optimised to detect ballistic missiles up to a range of 1000 kms (64N6).
  • As the time passed, the designers combined the medium high and low altitude coverage capability into a single LRSR called the ‘all altitude detection radar’(96L6E). Also, a totally new concept was introduced of having a ‘panoramic view 3D radar’ (91 N6).
  • The system contracted by us will have the latest all-altitude detection radar along with a radar optimised for ballistic missile detection. Besides this it will have an MFR of latest capabilities designed to direct missiles on the incoming threat.
  • All the above will produce a tremendous cumulative effect of carrying out surveillance of targets from 600-1000kms and an altitude coverage from low level to 56 kms. The radars will have the capability to track up to 300 targets at a time and engage up to 36 at any one time. It will be possible to take on ballistic missiles coming in up to speeds of 4800 m/s (this is far in excess to any known speed of ballistic missiles).
  • Besides ballistic missiles, the system equipped as above will have the capability to take on any type of air defence threat such as latest and futuristic multi-role strike aircrafts, stealthy targets, any type of UAS, cruise missiles, ARMs and more.

With reference to the interceptors of the S-400 following is pertinent.

  • It is one of those unique systems which can fire interceptors of different ranges from a single launch platform.
  • The interceptor missiles cover a range bracket of 40-400 kms (9M96E1-40 Km, 9M96E2-120Km.  48N6-250 KM and 40N6 -400Km).
  • Not only there is range flexibility, a degree of immunity is built into the missiles by configuring them on different guidance systems.
  • For instance, the missiles of 40 and 120 km range are configured on Command to Line of Sight (CLOS) guidance (in this the MFR tracks both the missiles and the target and guides the missile on the target). The 250 km  missile is based on Track Via Missile (TVM) guidance (in this the reflected radar waves from the target reach the ground station which guides the missile to the target. Hence the target does not come to know where the missile is coming from). Lastly the 400 km missile is based on active seeker, wherein the missile is only guided up to a point till its active seeker can home on to the target and thereafter guide the missile.
  • As stated, different types of guidance systems make the system more survivable in a hostile EW environment. Simply put, no one single type of attack (jamming, electronic deception, disruption etc.) will be able to disable the entire range of interceptors carried by the system.

The BMC2 of S-400 is a fully automated system capable of optimal utilisation of its resources (multiple radars, multiple interceptors and associated control systems)  for a seamless conduct of the air defence battle. Some important functions are given below.

  • Fusion of target data from multiple sensors to cut out duplication to generate a holistic Air Situation Picture (ASP).
  • Auto-interphase the inputs coming from higher air defence control nodes at the national level to update the air situation picture into friend and foe.
  • Take on the engagement of the assigned targets either in the missile defence or air defence mode.
  • Keeping in mind the fact that about 76% of all GBADWS inventory is of USSR/Russian origin, the integration of the BMC2 system of S 400 in the national level air defence grid is likely to be achieved seamlessly.

Impact of Induction

The weapon system will have the following impact.

In the field of GBADWS we are presently in the range and altitude bracket of 100+ kms and 36000 ft with sensor reach to 200-300 km. This system raises the bar several notches up to 400 kms, and 56000 ft with a sensor reach in the region of 600-1000 kms.

Its sensor inputs duly backed up with inputs from the sensors of Programme AD, AWACS and other long range early warning radars, will extend our overall look-see capability by hundreds of kms.

With this capability coverage, just three Regiments worth of sensors (and associated interceptors) could cover a significant portion of the Indo-Chinese border. It can cover a


When the contract was inked in Oct 2016, the initial deliveries had to start 36 months later and all the five regiments were to be delivered within four years, i.e in the time slot 2020-24. Slowdown due to Covid 19, caused the deliveries of our first regiment to be pushed forward to Dec 2021. During the recent three day visit of Defence Minister to Russia on 22 Jun, the point of sticking to the  earlier schedule for S 400  has been stressed.


With its exponentially enhanced capabilities the S-400 will surely be the game changer it is repeatedly referred to as.