Ballistic Missile Defence System For India A Realistic Assessment

Editor's Note

This article was penned down by Air Mshl Narayan Menon in 2012 when the successful launch of Agni -V SSM on 19 Apr 2012 was applauded by the country . It is being published due to its current relevance being debated regarding the cost factor of - "White Elephants in the Pipeline " , an MVI published article by Gp Capt TP Srivastava that actually triggered the re-emergence of this 13 years old article !

https://www.missionvictoryindia.in/post/white-elephants-in-the-pipeline

Editor ,MVI

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The successful launch of Agni-V surface-to-surface missile(SSM) on 19th April, 2012 has been applauded by the country. There were many downstream effects of this successful launch. India's DRDO claimed that it was a 5000km missile required to counter the growing missile capability of neighbours with inimical intentions towards India. Chinese experts claimed that the Agni-V had a range of 8000km and it was an ICBM. Pakistan responded with the launch of its own missile that could reach any target in India. The DRDO Chief has been quoted saying that the Agni-V can be tweaked to be employed as an anti-satellite(ASAT) missile also, though officially India has opposed the weaponization of space. A variant of Agni-V could emerge as an MIRV(multiple warhead, independently targeted re-entry vehicle), a capability that would boost India's strategic deterrence.

China is ahead of India in missile technology and capabilty. It has a large inventory of  short range ballistic missiles(SRBM range< 1000km), MRBMs(medium range 1000-3000km), IRBMs(intermediate range 3000-5500km) and ICBMs(intercontinentl range >5500km). China has the DF-5 silo-based ICBM with a range of 13000 km. The DF-31 and DF-31A with ranges of 7200 and 11200 km respectively can be silo-based or mobile. Pakistan, which clandestinely acquired missile technology from North Korea and China, began with the tactical missile HATF-1 with a payload of 500 kg and range of 80 km. The latest GHAURI-3 and SHAHEEN-3 IRBMs have ranges in excess of 3500 km carrying 1000 kg+ payloads. Both these are being developed and have been tested regularly. All these are nuclear-capable missiles. India's stated policy of 'no first use(NFU), renders it vulnerable to nuclear blackmail Given this environment, India has opted for a ballistic missile defence(BMD) system. On 07 May,2012 DRDO announced that a 'misile defence shield' has been developed and can be put in place at short notice at any two selected places. The announcemnt went on to state that the long range tracking radars and tracking devices, real-time data link and mission control systems needed for the operationalisation of the BMD have beeen'realised'. This system can tackle incoming ballistic missiles of speed upto 2000km. Phase II of the project would include improved ranges and would be in place by 2016.

BMD is a complex process that involves high levels of technology, is resource intensive and yet does not guarantee complete protection from  ballistic missile attacks. No BMD can assure 100% kills of incoming missiles. This was seen during the Gulf war when US Patriot systems were unable to shoot down Iraqi Scuds. The success rate of Patriot ant-ballistic missiles(ABMs) was reported to be less than 10%. Considering that the Scuds were of outdated technology, one can extrapolate that modern ballistic missiles will be far less vulnerable to BMD systems. Alternatively it could be stated that there is no fool-proof defence against a nuclear attack mounted through ballistic missiles. 

A ballistic missile follows a sub-orbital ballistic trajectory to deliver its warhead to the target. The missile trajectory comprises three parts: the powered initial phase, the free flight portion that constitutes most of the flight time and the re-entry phase where it re-enters earth's atmosphere.

These missiles can be launched from fixed sites or mobile launchers, aircraft, ships and submarines.Thepowered phase can last from few tens of seconds to several minutes depending on the range to be achieved and the weight of the war head. The initial thrust can be by a single rocket or multiple stage rockets. The missile is usually launched into a high sub-orbital trajectory and the highest point reached is 1200 km for an intercontinental missile. The missile enters free flight in space. In the re-entry stage atmospheric drag plays a significant part in the missile's trajectory right till impact point. Ballistic missiles are characteristically easy to detect and track once launched, but their hypersonic terminal phase velocity represents a real problem for defensive weapon systems. The problem is often described as 'hitting a bullet with another bullet', and the problem increases in difficulty as the range of the missile and its terminal velocity increase. Killing a Scud is easier than killing an IRBM, and killing an IRBM in turn is easier than killing an ICBM. The interception technology used has varied over time. In the 1960s, missile defense against ICBMs emphasized nuclear warheads. In recent decades non-nuclear kinetic warheads have been used. Directed-energy weapons such as lasers are also being employed though this technology is in the initial stages. 

Missile defense can be divided into categories based on various characteristics like type and range of missile intercepted, the trajectory phase where the intercept occurs, and whether interception occurs inside or outside the Earth's atmosphere. Ballistic missiles can be intercepted during the boost phase, midcourse phase or terminal phase.

Boost phase intercept is the easiest from a detection, tracking and kinematic perspective. The exhaust plume can be seen from orbit, and hundreds of kilometres away in the air. The missile is climbing at a supersonic speed, and early in the boost phase, will have all of its stages attached presenting a large radar target. The difficulty with boost phase intercept is that the defending aircraft, be it equipped with an interceptor missile or directed energy weapon (DEW), must be near enough to the launcher to effect a timely shot. This would entail long hours of 'patrol duty' for the defending fighters. Mid course phase intercepts are probably the most challenging from a detection and tracking perspective, as the missile is at the peak of its trajectory, and having shed booster stages is a small and cool radar target. Kinematically, mid course phase intercepts are demanding in terms of altitude, even if the missile's speed is comparatively low as it flies across the top of the ballistic arc. Terminal phase intercepts sees the delivery vehicle produce a prominent  trail and heat signature, as meltable coatings evaporate during re-entry. The ionisation plume provides a radar signature much larger than the vehicle itself, permitting a tracking system to cue precisely to the position of the warhead. The principal tracking challenge is discrimination between the re-entry vehicle and debris or countermeasures re-entering concurrently. The latter proved a major issue for Patriot intercepts of the Scud in 1991.

Missile defense can take place either inside (endoatmospheric) or outside (exoatmospheric) the Earth's atmosphere. The trajectory of most ballistic missiles takes them inside and outside the Earth's atmosphere, and they can be intercepted either place. There are advantages and disadvantages to either intercept technique. Endoatmospheric interceptions require lighter ABMs with inherently greater mobility. As range is limited, more numbers of ABMs need to deployed and decision time is reduced considerably and there is a danger of nuclear fallout over own areas. In exoatmospheric interceptions, more decision time is available and fewer numbers of ABMs are required to defend a larger area. However the ABMs would be heavier and less mobile.

A typical engagement sequence of a tactical ballistic missile would be as follows:

1. A missile is detected by the radar. This radar, which can discriminate between a missile, satellite and aircraft, reviews the speed, altitude, behaviour and radar cross-section of the target. If the data is consistent with the parameters set into the system, the missile is presented on the screen at the mission control centre(MCC).

2. The control officer reviews the target parameters again and orders the launch control centres(LCC) to bring their ABMs into 'operational' mode from 'stand by' mode. The system computers are continuously tracking and calculating the firing parameters.

3. The LCC decides which launch vehicle has the highest 'kill' probability, and orders them to fire. To ensure higher kill probability, two missiles are fired at predetermined intervals.

4. The fire control radar continues to track the target while simultaneously updating the outbound missiles with intercept information.

5. The active radar in the nose of the ABM acquires the hostile ballistic missile and manoeuvres towards it.

6. The attitude control motors on the ABM are fired for precisely alignment.

7. The ABM flies straight at the warhead of the hostile ballistic missile detonating and destroying the threat.

8. The second ABM locates any debris that may be a warhead and attacks it in a similar manner.

Indian BMD programme is planned as a two-tiered system withPrithviAir Defence (PAD) for high altitude interception and Advanced Air Defence (AAD) for lower altitudeinterception.ThePrithviAir Defence (PAD) is an anti-ballistic missile developed to intercept incoming ballistic missiles outside of the atmosphere (exo-atmospheric). Based on thePrithvimissile, PAD is a two stage missile with a maximum interception altitude of 80 km. The first stage is a solid fuelled motor while the second stage is Liquid fuelled. It has manoeuvre thrusters which can generate a lateral acceleration of more than 5gsat 50 km altitude. Guidance is provided by anintertialnavigation system with mid-course updates from LRTR and active radar homing in the terminalphase.PADhas capability to engage the 300 to 2,000 km class of ballistic missiles at aspeed of Mach 5. The PAD has also been called thePradyumna. LRTR is the target acquisition and fire control radar for the PAD missile. It is an active phased array radar having capability to track 200 targets at a range of600 km. Swordfish is an Indian long range tracking radar(LRTR) specifically developed to counter ballistic missile threat. It is  a part of India's ballistic missile programme. First testing of this radar was in March 2009. Main aim of the test was to validate the capabilities of the indigenously developed Swordfish.

Swordfish is an acknowledged derivative of the Israeli Green Pine long range radar, which is the critical component of that country's Arrow missile defence system. However, it differs from the Israeli system as it employs Indian transmit-receive modules, signal processing, computers and power supplies. It is also more powerful than the base Green Pine system and was developed to meet India's specific BMD needs. It is employed as the  target acquisition and fire control radar for the BMD system. It can  guide exoatmosphericinterceptor missile PAD to hit its target in space at an altitude over 80 km from earth. The Swordfish LRTR currently has a range of 600 km-800 km km range and can spot objects as small as a cricket ball (2-inches in diameter), which the DRDO plans to upgrade to 1,500 km by 2011.

9.  The PADE (Prithvi Air Defence Exercise) was conducted on November 2006 in which a PAD missile successfully intercepted a modified Prithvi-II Missile at an altitude of 50 km. The Prithvi-II ballistic missile was modified successfully to mimic the trajectory of M-11 missiles.

DRDO plans to test the anti-ballistic shield against missiles with a range of 1,500 km . The test will be conducted with a modified Prithvi missile launched from a naval ship and the anti-ballistic missile launched from Wheeler Island. The interception of the target missile will take place at approximately 80 km altitude.

On March 6, 2009 DRDO carried out a second successful test of the PAD interceptor missile. The target used was ship launched Dhanush missile which followed the trajectory of a missile with range of a 1,500 km. The target was tracked by Swordfish (LRTR) radar and destroyed by the PAD at 75 km altitude.

Advanced Air Defence (AAD) is an ABM designed to intercept incoming ballistic missiles in the endo-atmosphere at an altitude of 30 km. AAD is single stage, solid fuelled missile. Guidance is similar to that of PAD: it has an inertial navigation system, midcourse updates from ground based radar and active radar homing in the terminal phase. It is 7.5 m tall, weighs around 1.2 t  and a diameter of less than 0.5 m.

On 6 December 2007, AAD successfully intercepted a modified Prithvi-II missile acting as an incoming ballistic missile enemy target. The endo-atmospheric interception was carried out at an altitude of 15 km. The interceptor and all the elements performed in a copy book fashion validating the endo-atmospheric layer of the defense system. The launch was also shown through a video link at a control room of DRDO at Bhawan, Delhi.

Due to two successful interceptor missile tests carried out by India, the scientists have said that the AAD missile could be modified into a new extended range (up to 150 km surface to air missile that could be possibly named as ‘Ashvin’.

On 15 March 2010, AAD interceptor missile test from the Orissa coast on Monday was aborted, as the target missile deviated from its path and plunged into the sea. The AAD missile was to intercept the target at an altitude of 15 to 20 km over the sea. The target, a Prithvimissile, fired at 10:02 am from a mobile launcher from the Integrated Test Range Complex-3 at Chandipur-on-Sea, 15 km from here, deviated from its trajectory after traveling about 11 km and fell into the sea. On 26 July 2010, AAD was successfully test-fired from the Integrated Test Range (ITR) at Wheeler Island off the Orissa's east coast.

On 6 March 2011, India launched its indigenously developed interceptor missile from the Orissa coast.Indiasuccessfully test-fired its interceptor missile which destroyed a 'hostile' target ballistic missile, a modified Prithvi, at an altitude of 16 km over the Bay of Bengal. the interceptor, Advanced Air Defence (AAD) missile positioned at Wheeler Island, about 70 km across sea from Chandipur, received signals from tracking radars installed along the coastline and travelled through the sky at a speed of 4.5 Mach to destroy it.As the trial was aimed at achieving the desired result with precision, theinterceptor missile had its own mobile launcher, secure data link for interception, independent tracking and homing capabilities and sophisticated radars. On 10 February 2012, AAD was again successfully test-fired from from Wheeler Island off the state coast near Dhamra in Bhadrak district. Though successful, these trials have been conducted under laboratory conditions.

The Phase 2 missile defense system will be based on the AD-1 and AD-2 interceptor missile that are currently under development. Phase 2 interceptors will have speeds of 6-7 Mach and they will be hypersonic. Missiles will have lesser time to intercept. Guidance systems have to be far more energetic and quick responsive. Ground testing of the AD-1 was to begin in 2011 and AD-2 in 2012, but there have been no reports of any tests so far. These interceptors would be capable of shooting down missiles that have ranges greater than 5,000 km, which follow a distinctly different trajectory than a missile with a range of 2,000 km or less. During their final phase, ICBMs hurtle towards their targets at speeds twice those of intermediate range missiles. The Phase 2 system will match the capability of the THAAD or Terminal High Altitude Area Defence missiles deployed by the United States as part of its missile shield beginning this year. THAAD missiles can intercept ballistic missiles over 200 km away and track targets at ranges in excess of 1,000 km.

The successes achieved by the DRDO in the field of ballistic missiles is indeed laudable and they have promised much more. But the BMD system is a complex entity and many other components are required to make it operational. The economic and strategic costs also have to be calculated to determine if other alternatives to BMDs are available to the country.

A comparison with the US BMD system would be useful. USA has the most elaborate BMD system being put in place and there is a plan to extend it further into Europe. The US continental system is estimated to have cost about USD 100 billion from 2002 till date. A billion USD is approximately Rs 5000 crores. The Indian system will cost less but the amount involved will be between Rs 50,000 crores to Rs250,000 crores. And this sort of phenomenal expenditure will not guarantee complete protection. A viable alternative would be to improve our strategic nuclear strike capability so that despite NFU, India will have the capacity to absorb a nuclear attack and respond in a manner to destroy the enemy. The opposition of Russia to the US plan to station ABMs in eastern Europe is mainly because the strategic balance will be altered. A similar situation can occur on the sub-continent resulting in fuelling the arms race between India and Pakistan. India is at the learning stage for many of the complex technologies required to create a BMD system. Other countries will be reluctant to share their expertise in this area. DRDO's record in creating weapon systems for our armed forces has not been encouraging as exemplified by the delayed induction of the LCA, the failure of the Arjun MBT and the virtual rejection of the INSAS rifle by the Indian Army. But leapfrogging on the success achieved by scientists in space-related technologies, DRDO has excelled in producing potent ballistic missile that have enhanced India's strategic options. Perhaps it would be wiser to channel our resources in an area of strength, rather than experimenting in a hugely expensive sector where even the achievement of success is not a guarantor of increased security. Many other questions also arise. Which regions or entities will be protected by the BMD system? Will the enemy attack  'protected areas' with larger numbers of ballistic missiles to neutralise the BMD? How many systems will be required? Will the systems be manned round the clock? Will India be able to bear the very high running costs of the BMD system? Will we put sensors in space for increased early warning? There needs to be greater debate on the pros and cons of the ballistic missile defence system and its viability and a cost-benefit analysis should be carried out. The opportunity costs involved must be clearly evaluated even at this stage when two systems are reportedly ready for induction.

Narayan Menon

References:

1. Wikipedia

2. DRDO Home Page

3. Article by Peter J Brown, 2009 Asia Times Online

4. Theatre BMD Systems by Dr Carlo Kopp, 2008 updated 2012

5. Times of India-20 April, 2012

6. Deccan Herald-07 May, 2012