Gravitational assist

Gravitational assist, also known as a gravity assist or slingshot, is a technique used in space travel to increase a spacecraft’s speed and alter its trajectory by passing close to a planet or moon. As the spacecraft approaches a celestial body, it is pulled in by gravity, gaining energy. When it swings around and departs, it leaves with increased speed, effectively borrowing some of the planet's momentum. This method allows spacecraft to reach distant destinations with less fuel, making missions more efficient and cost-effective.