What is the primary function of countermeasure flares?

Countermeasure flares are specifically designed to engage and divert enemy infrared and heat-seeking missiles, which is crucial in protecting aircraft and other targets from these types of threats. The flares emit a high-intensity heat signature that is significantly hotter than the aircraft, thereby attracting the missiles away from their original target. This defensive mechanism is vital for ensuring the safety of airborne assets in hostile environments where they may be targeted by such missiles.

Other functions listed, like illuminating the battlefield or signaling troop positions, can be achieved by different types of devices or methods but are not the primary purpose of countermeasure flares. Additionally, providing guidance to missiles is unrelated to the function of flares, as they are not designed to guide missiles but rather to mislead them.