A satellite's orbital speed is at its maximum when it is closest to the body it is orbiting. This point in the orbit is called the perigee for orbits around Earth, or periapsis for orbits around other celestial bodies.

Here's why:

* Conservation of Energy: A satellite's orbital energy remains constant. This energy is the sum of its kinetic energy (due to its motion) and its potential energy (due to its position in the gravitational field).

* Gravitational Potential Energy: As the satellite moves closer to the body it orbits, it loses potential energy (since potential energy is higher the farther away you are from a gravitational source).

* Kinetic Energy: To compensate for the loss of potential energy, the satellite gains kinetic energy, resulting in a higher speed.

Therefore, the closer a satellite is to the body it orbits, the faster it moves to maintain a stable orbit.