Oberth Effect

The Oberth Effect explains that a rocket gains more speed when it fires its engine at higher speeds, particularly near a planet or at a low altitude. Because the rocket is already moving fast, applying the same amount of fuel produces a larger increase in velocity compared to doing so at lower speeds. This is why spacecraft often perform engine burns when close to a planet or moon—using the gravitational energy boost—making maneuvers more efficient and saving fuel in the process. Essentially, the effect shows that producing acceleration at higher speeds yields greater changes in energy.