E.g. when cosmic probe is passing a planet in direction of movement of this planet the gravitational interaction between the probe and the planet accelerates the probe (pushes the probe forward) and the probe gains kinetic energy during the encounter with the planet. | E.g. when cosmic probe is passing a planet in direction of movement of this planet the gravitational interaction between the probe and the planet accelerates the probe (pushes the probe forward) and the probe gains kinetic energy during the encounter with the planet. |