Infrared homing refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track and follow it. Missiles which use infrared seeking are often referred to as "heat-seekers", since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and retain heat, and as such, are especially visible in the infra-red wavelengths of light compared to objects in the background. http://en.wikipedia.org/wiki/Infrared_homing
Και πύραυλοι υπέρυθρης αναζήτησης (εδώ, όπου βρέθηκα ψάχνοντας αν υπάρχει η λέξη θερμοβολίδα· που, ναι, υπάρχει, αλλά είναι αντίμετρο κατά των πυραύλων υπέρυθρης αναζήτησης).