The Exocet Threat
The danger posed to the British fleet by ‘state of the art’ Argentinian Exocet anti-ship missiles (produced by the French company Aerospatiale) was brought home when HMS Sheffield, one of Britain’s most modern and sophisticated destroyers, was caught by surprise and succumbed to one missile hit early in the conflict. The damage to the warship was accentuated by internal watertight doors being blown off their mountings and the missile’s burning propellant and associated thick smoke being spread around the damaged area.
Although portable computing power was in its relative infancy in 1982, a great deal of resource had been invested in developing onboard computing systems for missiles that could run complex mathematical algorithms. In the case of an Exocet, the missiles were programmed to skim the waves under gyro control towards target coordinates passed to them by the launching aircraft. They were described as 'Fire and Forget' weapons, because once fired the missiles would independently attack the target whilst the launch aircraft made their escape.
The idea was that the attacking aircraft having superior radar and pilot oversight would be able to identify the correct target. And then, once activated, the missile would fly straight towards its destination without any possibility of being distracted along the way by ship-launched chaff. Its low attack altitude meant that only the most modern and sophisticated radar controlled weapons systems would have a chance of destroying it in flight.
This left the chance that an identified target might manoeuvre away at high speed to avoid being hit. The Exocet missile control system dealt with this by turning on the missile’s own radar as it approached its destination to look for the target’s final location within a specified escape zone. The onboard navigation system then adjusted the missile’s course accordingly.
It is understood from technical experts who have insights about how the Argentines prepared for the Exocet attack of 25th May, that the assisting French technicians helped set up the missiles so they were primarily looking for targets of carrier size and manoeuvrability. In practical terms, this meant the Exocets would switch on their homing seekers at around five miles out from where the pilot had first identified a suitable target using the aircraft radar.
There was a faint possibility, therefore, of defending units using chaff or a sufficiently bulky solid decoy to make an Exocet turn the wrong way on its final approach. The use of such tactics was included in Royal Navy anti-missile warfare training of the time and rehearsed during the campaign itself.