Which component protects the missile's optical path from debris and moisture?

• A. Acquisition indicators
• B. Humidity indicator
• C. IR Window & Blow Out Disk
• D. Rear sight reticles

Answer: (C)

Protecting the missile’s optical path means keeping debris and moisture away from the infrared sensor while still letting infrared energy pass through. The infrared (IR) window is that protective, transparent seal at the seeker’s nose; it keeps dust, rain, and humidity from reaching the detector and is designed to transmit IR wavelengths with minimal loss. The blow-out disk adds a safety function: it vents pressure in a controlled way if the nose area is compromised, helping prevent damage to the window and the optical path itself. Together, they form the protective barrier for the seeker’s optics during launch and flight. The other items don’t shield the optical path—acquisition indicators, humidity indicators, and rear sight reticles serve different roles related to targeting and flight handling.