How does the Oberth effect work?
In: Physics
This is also called a “Powered Fly-by.” As a spacecraft enters the gravitational field of an object (normally a planet, star, or moon), the spacecraft accelerates due to the gravity. The pilot fires thrusters in the same direction in order to “fall faster” into the gravitational field. This allows them to attain a higher speed than just firing those thrusters alone. (They will not be falling toward the planet. Rather, they’re “falling” *past* the planet.)
Spacecraft will use this powered flyby to “slingshot” themselves off the gravitation field. This is how we sent some of our spacecraft to Mars. We used a powered flyby with the Moon’s gravity, taking advantage of the Oberth Effect. These powered flyby’s are much more fuel efficient that just flying/accelerating in empty space. Sometimes, a pilot will even some fuel to slow the spacecraft down in order to fall into the gravitational field correctly so they can use less fuel overall to attain the speed and direction (velocity) desired.
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