Oberth effect

Type of spacecraft maneuver

In astronautics, a powered flyby, or Oberth maneuver, is a maneuver in which a spacecraft falls into a gravity well and then uses its engines to further accelerate, thereby achieving additional change in speed. The resulting maneuver is a more efficient way to gain or lose kinetic energy than applying the same impulse outside of a gravity well. The gain in efficiency is explained by the Oberth effect, wherein the use of a reaction engine at higher speeds (relative to any reference frame) generates a greater change in mechanical energy than its use at lower speeds.

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