Maarg Manthan · Topic 16.5

Anti-Ballistic Missile System

Science & Technology › Defence Technology and Missile Systems · Topic 16.5

An anti-ballistic missile system, also called ballistic missile defence, detects, tracks and destroys incoming ballistic missiles before they strike. It has early warning radars, command and control centres and interceptor missiles. Interception is possible in the boost phase, the midcourse phase in space, or the terminal phase after re-entry. India's Ballistic Missile Defence programme of DRDO, begun after the Kargil War, has two layers. The Prithvi Air Defence, PAD, intercepts at 50 to 80 km altitude outside the atmosphere's lower part and was first tested in November 2006. The Advanced Air Defence, AAD, intercepts inside the atmosphere at 15 to 30 km and was first tested in December 2007. The Phase-I system covers missiles of up to 2,000 km range. A hit-to-kill method is used.

5 min read · UPSC Prelims · Science & Technology · Defence Technology and Missile Systems

At a Glance

Programme DRDO Ballistic Missile Defence
High layer PAD, exo-atmospheric
Low layer AAD, endo-atmospheric
Radar Swordfish
Method Hit-to-kill
Exam link UPSC Prelims, Science & Technology: Defence Technology and Missile Systems

Where Does It Fit?

This topic follows the account of BrahMos. It shifts from offence to defence against missiles, which links with the later topic on air defence systems. Previous topic: BrahMos Missile System. Next topic: Hypersonic Glide Vehicles and Hypersonic Cruise Missiles.

How Does Ballistic Missile Defence Work?

Element	Details
Early warning	Long range radars and satellites detect launches and track the missile. India’s Long Range Tracking Radar, called Swordfish, is based on Israel’s Green Pine radar and can track objects up to about 600 km
Command and control	Computers estimate the path of the missile and assign interceptors
Interceptor	A missile that rises to meet the target. Hit-to-kill interceptors destroy the warhead by direct collision, and blast fragmentation types use a warhead near the target
Phases	Boost phase, midcourse in space, and terminal phase after re-entry. Defence in the terminal phase has little time
Exo-atmospheric	Interception above about 80 km, outside the atmosphere
Endo-atmospheric	Interception within the atmosphere, below about 30 km
Layered defence	Two layers give a second chance if the first fails

What Is India’s BMD Programme and How Does It Compare?

Beginning: the programme began in 1999 to 2000 after the Kargil War, and was approved by the Government in 2000s
Prithvi Air Defence: PAD, a two stage interceptor, tested in 2006 and used the Prithvi missile as a base
Prithvi Defence Vehicle: PDV, an exo-atmospheric interceptor tested in 2014 which hit a target at about 120 km
Advanced Air Defence: AAD, a single stage solid fuelled interceptor tested from 2007 and intercepts at about 15 to 30 km altitude
Phase-I: capable of intercepting missiles of up to 2,000 km range, developed to a deployable level by DRDO and declared ready around 2012
Phase-II: to counter missiles of 5,000 km range, with new interceptors AD-1 and AD-2, tests of which were reported from 2022 onwards. Check the current status
Protected areas: plans first covered Delhi and Mumbai
Other systems: the Russian S-400 Triumf, bought in 2018, has some anti-ballistic capacity

What Else Should You Remember?

Aegis: a United States naval system for ballistic missile defence
THAAD: Terminal High Altitude Area Defense, a United States system
Patriot: an older United States system
Iron Dome: Israel’s short range rocket defence system
Arrow: Israel’s longer range anti-ballistic missile system
Golden Dome: a United States plan announced in 2025 for a layered homeland defence
Sudarshan Chakra Mission: announced by the Prime Minister in August 2025, a plan to build a national air defence shield by 2035
Dual capable radars: radars that support both air and missile defence
Cost exchange: interceptors can cost more than the missile they stop
Saturation: a large number of missiles and decoys can overwhelm a defence
Counter measures: MIRVs, decoys and manoeuvring warheads make interception harder
ABM Treaty: the United States and Soviet Union signed it in 1972, and the United States withdrew in 2002
Space based sensors: satellites that detect heat from launches
Stability debate: defence may tempt a state to think it can launch a first strike safely
Link to deterrence: India’s missiles are in India’s Missile Systems: Prithvi, Trishul, Nag, Akash, Agni Series
Link to hypersonics: new threats that are hard to catch are in Hypersonic Glide Vehicles and Hypersonic Cruise Missiles
Link to air defence: other layers are in Air Defence Systems
Early warning radar role: an early warning radar gives minutes of notice, which decide whether interception is possible
Kargil link: the programme began after the Kargil War of 1999, which led to a review of air and missile defence
Tracking range: radar range and the speed of the missile decide the time available

Why Does It Matter for the Exam?

Layers: PAD high and AAD low
Method: hit-to-kill
Phase-II: 5,000 km capability
Current affairs link: Sudarshan Chakra Mission and Phase-II tests
Common errors: mixing PAD and AAD altitudes or calling Akash an ABM system

As an analytical point, missile defence is expensive and cannot give a perfect shield, but it adds to deterrence by raising an attacker’s uncertainty. Layering, sensors and cost-effective interceptors are the main challenges.

Why Is This Topic Important?

Layers PAD and AAD
Phases I and II
Limits Cost, saturation

What Came Next?

The next topic covers hypersonic glide vehicles and hypersonic cruise missiles. Next topic: Hypersonic Glide Vehicles and Hypersonic Cruise Missiles.

Key People and Terms

BMD Ballistic missile defence
PAD Prithvi Air Defence
AAD Advanced Air Defence
Hit-to-kill Interception by collision
Exo-atmospheric Above the atmosphere
Endo-atmospheric Within the atmosphere

Exam Corner

Points to Remember

PAD test: 2006; AAD test: 2007.
PAD above 80 km; AAD below 30 km.
Phase-I: up to 2,000 km missiles.
Phase-II aims at 5,000 km missiles.
Sudarshan Chakra Mission announced August 2025.

Do Not Confuse With

PAD and AAD High exo-atmospheric versus low endo-atmospheric
ABM and SAM Against ballistic missiles versus aircraft and low missiles
Hit-to-kill and blast fragmentation Collision versus warhead near the target

Memory Hook

Swordfish sees, PAD goes high, AAD goes low, hit to kill.

Mains Angle

Questions ask for layers, altitudes and phases. These points help.

Need Missile threat
System Two layers
Limits Cost

A Question You May Face

An original practice question, not a past paper question.

“Explain the working of ballistic missile defence and assess India’s progress in developing an anti-ballistic missile system.”

How to Answer

Threat Missile risk.
Working Phases.
India PAD, AAD.
Limits Cost.

GS Relevance

Prelims: BMD layers, PAD, AAD, S-400, other systems. GS Paper 3: defence technology and security.

Frequently Asked Questions

What is an anti-ballistic missile system?

An anti-ballistic missile system is a defence that detects, tracks and destroys incoming ballistic missiles. It consists of early warning radars, command and control centres and interceptor missiles that rise to meet the target in space or in the lower atmosphere, usually destroying it by colliding with it.

What are PAD and AAD in India's BMD?

Prithvi Air Defence, PAD, is the upper layer interceptor that works outside the atmosphere at about 50 to 80 km or more, while Advanced Air Defence, AAD, is the lower layer interceptor that works inside the atmosphere at about 15 to 30 km. Together they form a two layer shield against incoming missiles.

What is hit-to-kill technology?

Hit-to-kill is a method in which the interceptor destroys the incoming warhead by direct collision, using the kinetic energy of the impact and not an explosive warhead. It needs very precise guidance. India's Prithvi Defence Vehicle and Advanced Air Defence interceptors use this approach in tests.

What is the range of missiles that India's BMD Phase-I can stop?

Phase-I of India's ballistic missile defence is designed to intercept ballistic missiles of up to about 2,000 km range. Phase-II aims at stopping longer range missiles, up to about 5,000 km, with new interceptors, and tests have been reported, but its deployment status should be checked.

What is the Sudarshan Chakra Mission?

The Sudarshan Chakra Mission was announced by the Prime Minister in his Independence Day speech in August 2025. It aims to build a national shield against enemy air and missile attacks over the next decade, using indigenous systems, and the details of the plan are still being worked out.

PYQ Practice — Statement Analysis

1 PAD is an exo-atmospheric interceptor.

True

Above the atmosphere.

2 AAD intercepts at altitudes above 80 km.

False

It works at about 15 to 30 km.

3 Hit-to-kill destroys a warhead by collision.