The Oberth effect occurs when a rocket is flying close to a celestial body. The rocket is able to speed up while getting closer to the celestial body to change its orbit.
Basics[]
All engine burns done at periapsis will rise or lower the apoapsis, vice versa. Engine burns at any other point in an orbit will result in complex changes and more fuel consumption.
For the burn to be more efficient, it must be done in the same direction of the trajectory the rocket is moving (prograde). Engine burns done in an angle (or radially) are less efficient.
Transfer windows[]
- Main article: [[Transfer Window]]
For an interplanetary flight, the simulator displays transfer windows as a highlighted area, both along the orbit of the rocket and along the orbit of the planet. To save more fuel, if the transfer window allows, a rocket can perform several engine burns, taking advantage of the Oberth effect.
Deep space maneuvers don't take advantage of the Oberth effect and so they consume more fuel.
Trivia[]
- The Oberth effect is named in honor of German astrophysicist Hermann Oberth.