How do heat-seeking missiles work? do they work exactly like in the movies?

Question

How do heat-seeking missiles work? do they work exactly like in the movies?

In: Technology

Answer 1

One thing usually gotten wrong in movies is that most missiles, including many if not all heatseekers, have a rocket engine that burns only for the first few seconds of flight.
Hence, kinetic energy of the missile starts getting lower once the engine shuts off, and the missile is less maneuverable and therefore has a lower chance of hitting a maneuvering target at longer range.

Therefore, maximum range and maximum effective range can be quite different.
Some missiles do have sustainer rocket engines to maintain propulsion over a longer period of flight but I can’t think of any heatseeker missiles with sustainerers.