Terminology Related to Missiles

How are nuclear bombs delivered?

In the early days of their development, nuclear bombs were extremely heavy and could only be dropped by bombers, as on the only occasion they were used in actual combat in Hiroshima and Nagasaki. Starting from the 1950s, the Cold War period saw the development of several ways of delivering nuclear weapons. Nuclear artillery shells, land mines, torpedoes, mortar, portable rocket launchers and even suitcase-sized munitions were developed to be used as atomic bombs. But these methods were extremely expensive with little damage potential and later it was realized that the best way to deliver nuclear bombs was by using them as warheads of missiles. A nuclear-capable ICBM is more than 20 times faster than a bomber, 10 times faster than a fighter plane and is capable of carrying tonnes of nuclear warhead. A cruise missile, on the other hand, would do less damage but be far more accurate. Cruise missiles can also be air-launched.

How is a missile different from a bomb or rocket?

A missile is a rocket-propelled weapon designed to deliver an explosive warhead with accuracy and speed. A bomb is simply a warhead, and once released is completely governed by the laws of ballistics, meaning the only force that acts upon it after it is released is the force of gravity. If we attach any type of propulsion system to a bomb, it becomes a rocket. Because of its means of propulsion, a rocket can travel farther and faster than a bomb. If a guiding and control mechanism is attached to a rocket, it becomes a missile, which can be further classified in various ways. The classification can be based on origin and target — surface-to-surface missile (SSM), air-to-surface missile (ASM) etc, or on the working principle — ballistic versus cruise missiles, or their purpose — strategic and tactical missiles.

What is the difference between ballistic and cruise missiles?

 A ballistic missile is used to hit a predetermined target. Its trajectory can roughly be divided into two phases. It is launched in such a way that it burns most of its fuel to attain the desired velocity in the first phase called the boost phase. The missile can only be guided during the powered phase of flight. The second phase starts after shutting down of the rocket engine. The missile is now governed by laws of orbital mechanics and ballistics and follows the flight pattern of its powered phase to hit the target. Although it’s easy to detect a ballistic missile, it’s almost impossible to intercept it. However, a warning is easy to make and hence people can take steps to decrease the extent of damage. During the first Gulf War, people in Tel Aviv and Riyadh were always warned about Scud attacks from Iraq so that they could wear gas masks and move into safe shelters. Unlike a ballistic missile, a cruise missile is a small pilotless aircraft that carries an explosive warhead. It has wings and an engine and is designed to be extremely accurate. It is steered by an inertial navigation system (INS), which is also used by aeroplanes. More recent cruise missiles also have a global positioning system. A cruise missile can be made so accurate that it can be aimed at any specific place like a door or window of a building. The indigenously developed Agni and Prithvi are ballistic missile systems, while BrahMos is a cruise missile system.

What are strategic and tactical missiles?

Ballistic missiles are categorized according to their range, which is the maximum distance measured along the surface of the earth from the point of launch of a ballistic missile to the point of impact of the last element of its payload. In the US, they are divided into four classes — Intercontinental Ballistic Missile or ICBM (over 5,500km), Intermediate-Range Ballistic Missile or IRBM (3,000 to 5,500km), Medium-Range Ballistic Missile or MRBM (1,000 to 3,000km) and Short-Range Ballistic Missile or SRBM (up to 1,000km). The Russian system, on the other hand, classifies them as Strategic (over 1,000km), Operational-Strategic (500-1,000km), Operational (300-500km), Operational-Tactical (50-300km) and Tactical (up to 50km). There can be considerable overlap between these definitions. For example, Scud missiles were used by Iraq as tactical missiles to hit closer targets.