From The Popular Mechanics:
Aerospace designers give the joint strike fighter a stealthy, high-tech aiming system. Here is how it works.
Aiming weapons from a stealth aircraft like the F-35 is not easy. The infrared sensors used to find targets in the air and on the ground need a 360-degree view, so they must hang outside the airframe. However, the shape of any exterior hardware produces a telltale signature on enemy radar, so Lockheed Martin engineers put the targeting optics in a multifaceted sapphire structure jutting out of the fuselage under the aircraft’s nose. “The material is the same as you find in a supermarket checkout bar-code scanner,” says Don Bolling, Lockheed’s business development manager for the electro-optical targeting system (EOTS).
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