The purpose of the fixed control surfaces used on guided munitions is to

• A. Stabilize the weapon in flight.
• B. Control the altitude
• C. Increase velocity
• D. Steer to the target

Answer: (A)

The key idea is passive aerodynamic stability. Fixed control surfaces act as stabilizers, creating restoring moments that keep the munition oriented along its flight path and resisting disturbances like gusts or tumbling. This stable baseline lets the onboard guidance system make precise adjustments with any movable control surfaces, rather than fighting an unstable platform. They don’t directly set altitude or speed—those are governed by the flight path and propulsion—and steering to the target is achieved by actuated surfaces, not the fixed ones.