Why is the reentry burn performed by vehicles like the Falcon 9 crucial?

Answer

Reducing the peak heat flux that the structure must endure

The reentry burn, performed while still at hypersonic speeds, is a crucial technique for active control used to reduce the maximum intensity of the heat pulse the structure must withstand.

Why is the reentry burn performed by vehicles like the Falcon 9 crucial?

#Videos

How Do Spacecraft Survive Re-Entry? - YouTube

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