Which characteristic describes the thrust curve of a regressive motor burn?

The characteristic that describes the thrust curve of a regressive motor burn is one where there is a high initial thrust relative to the ending thrust. This means that during the burn phase, the motor initially produces a significant amount of thrust, which then decreases as the fuel is consumed. This type of thrust curve is typical in engines designed to maximize short bursts of high power for initial lift or acceleration, often seen in applications where rapid performance is crucial.

In contrast, a consistent thrust throughout the burn would indicate a different type of engine design, one that maintains a stable output over time. A gradual increase in thrust to a peak would describe a progressive burn motor, where the thrust builds up and then declines, while a flat thrust curve with minimal variation suggests a constant power output, which again does not align with the characteristics of a regressive burn motor. Therefore, the correct description of a regressive motor burn is indeed characterized by the initial high thrust that tapers off towards the end.