Beyond operational control, what challenge do aging solid fuels present regarding mission predictability?

Answer

Chemical changes and thermal cycling can cause internal cracking, altering the surface area and changing the intended thrust profile over time.

Internal degradation in the solid grain changes its physical shape over time, which directly affects how much surface area is burning, leading to an unpredictable thrust curve during flight.

Beyond operational control, what challenge do aging solid fuels present regarding mission predictability?
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