What does the RPG-7 sustainer motor do?

The sustainer motor of the RPG-7 is designed to maintain the flight of the rocket for the distance to the target, ensuring that it travels the full intended range before reaching its target. After the initial launch phase, where the rocket is propelled forward, the sustainer motor ignites to provide continuous thrust. This allows the rocket to stabilize and maintain its trajectory, enhancing accuracy and effectiveness.

In contrast, the other options do not accurately represent the function of the sustainer motor. For instance, it does not have a role in igniting the warhead upon impact, as that function is distinct from sustaining flight. Similarly, while the sustainer motor helps control flight after launch, it does not carry the rocket for a specific initial distance like the first 11 meters, and it certainly does not serve to cool down the rocket during launch, as that is not within its operational design. Thus, the primary purpose of the sustainer motor is clearly focused on maintaining the rocket's flight path towards the intended target.