Countermeasure

This article is about weapons. For Computer Security Countermeasure, see Countermeasure (computer).

A CH-46 Sea Knight helicopter launches countermeasures (flares)

Fortification, a passive countermeasure

A countermeasure is a measure or action taken to counter or offset another one. As a general concept it implies precision, and is any technological or tactical solution or system (often for a military application) designed to prevent an undesirable outcome in the process. The first known use of the term is in 1923.

Countermeasures can refer to the following disciplinary spectrum:

• defense
• medicine
• materials engineering
• electro-magnetic engineering
• policing
• Information technology
• Law
• Diplomatic security
• Pollution prevention

Defense countermeasures are often subdivided into "active" and "passive" countermeasures.

Active

"Active" countermeasures alter the electromagnetic, acoustic or other signature(s) of a target thereby altering the tracking and sensing behavior of an incoming threat (e.g., guided missile) are designated soft-kill measures. Measures that physically counterattack an incoming threat thereby destroying/altering its payload/warhead in such a way that the intended effect on the target is majorly impeded are designated hard-kill measures. Both are further described in active protection systems.

Passive

"Passive" countermeasures include:

• Armor
• Camouflage
• Fortification
• Self-sealing fuel tank

See also

• Electronic countermeasures
• Infrared countermeasures
• Flare (countermeasure)
• Anti-aircraft
• Anti-ballistic missile
• National Missile Defense
• Strategic Defense Initiative
• Mine countermeasures