What is the function of the drag brakes deployed on the booster during descent?

Answer

To help slow the booster down significantly before the engine restart phase

Drag brakes are deployed on the booster to provide substantial deceleration, which is necessary before the main engine restarts for the controlled landing sequence.

What is the function of the drag brakes deployed on the booster during descent?

#Videos

Blue Origin NS-33 New Shepard launch and landing - YouTube

reusableBlue OriginNew Shepard