The $85,000 AIM-9 Sidewinder missile

This air-to-air missile mercilessly seeks out its prey – there’s little chance of escape

Named after a venomous                                       snake that is sensitive to         

infrared and so can sense the

heat of its prey, the deadly

Sidewinder missile does much the same.

First tested in 1953, the Sidewinder is a

heat-seeking, short-range air-to-air

missile used by fi ghter aircraft. Once

launched, it will fl y towards a hot target –

usually the engines of an aircraft or

another missile.

The key to the system is hidden in the

nose of the missile. The seeker consists of

an array of sensors that react to infrared

light; similar in principle to the CCD

sensor in a digital camera but simpler in

that it only judges its surroundings as

‘very hot’ or ‘not very hot’. In other words

it can ‘see’ heat. The sensors, plus its

assembly of mirrors and lenses, spin off

centre so that they can scan a wide vista

and also work out where the heat is in

relation to the missile. For instance, if the

target is over to the right, the sensors will

detect more infrared when they are

aimed in that direction.

The sensors feed information to the

guidance control system that, in turn,

move the fi ns at the back of the missile to

steer the Sidewinder towards the target.

Or rather, aim it at a point slightly ahead

of the target to ensure that it doesn’t end

up chasing it and never catching it. This

is called proportional navigation and

effectively anticipates where the target                 will be at the point of impact.

In fact, the Sidewinder doesn’t actually

impact with its target, but is designed to

explode just before it hits it, to ensure

maximum damage. Lasers positioned

behind the forward fi ns emit light, and

when the missile is close to the target,

the light bounces off it and back to

sensors on the missile, telling the

systems to trigger the warhead.

The Sidewinder is launched from an

aircraft and is initially propelled by a

rocket motor that hurls it forward at a

speed of Mach 2.5 (about 3,060km/h).

Once the fuel has been used, the missile

glides the rest of the way to its target

Deployment

It is estimated that

Sidewinder missiles have

killed around 270 people

worldwide over the last 50-

plus years. Over 110,000

missiles have been produced

for 28 countries and just one

per cent of them have been

used in combat. Here are just

some of the war zones where

the missile has seen action: 

1. Second Taiwan                               Strait crisis

Date: 1958

Location: Taiwan Strait,

Taiwan

2. Vietnam war

Date: 1959-1975

Location: North Vietnam

3. Falklands conflict

Date: 1982

Location: Falkland Islands

4. Lebanese civil war

Date: 1975-1990

Location: Bekaa Valley,

Lebanon

5. Gulf war

Date: 1990-1991

Location: Persian Gulf

6. Soviet–Afghan war

Date: 1979-1989

Location: Afghanistan