“A man’s desire to explore the universe has no bounds but nature has its way.” Picture Source: Google A gravity assist manoeuvre, also known as “gravitational slingshot” or “swing-by” is the technique in orbital mechanics to change the speed (either accelerate or deaccelerate) or trajectory(having either higher energy or lower energy) of the orbit of a spacecraft by the use of the relative movement(with respect to the Sun) and gravity of astronomical objects, without the use of any fuel. The basic principle of the gravity assist manoeuvre is to either gain momentum from or lose momentum to a planet (or any other astronomical body) while moving past it, which changes the spaceship's trajectory and speed relative to the Sun. At the meantime, the speed and trajectory of the planet are also affected but the effect is insignificant due to its huge mass as compared to that of the spacecraft. Depending on the relative direction of motion of the planet and...