Why does the lunar exploration satellite have to change its orbit many times to reach the orbit around the moon?

For Chang 'e-1, "orbit change" means changing the flight orbit. If the satellite is launched directly from the ground to the earth-moon transfer orbit, it will need a rocket with much greater propulsion than the "Long March 3A" and the launch cost will double. In this launch, the satellite was first put into a super-geosynchronous orbit with an orbital period of 16 hours, and waited for the moon to fly over while the satellite was orbiting the earth, and gradually increased its speed through orbit change. "Chang 'e-1" needs to change its orbit many times during its flight, and finally accelerates to the entry speed of the earth-moon transfer orbit, and realizes the goal of flying to the moon through the satellite's own maneuverability. Although it increases the control difficulty, it can make room for timely and accurate adjustment through multiple orbit changes, and on the other hand, it can save fuel costs.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. The orbit of the satellite is elliptical, so the way to save rocket fuel can be to launch it into a large elliptical orbit first. When the satellite is at apogee, adjust the attitude above the satellite to ignite the rocket, so that the orbit of the satellite becomes the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. The orbit of the satellite is elliptical, so the way to save rocket fuel can be to launch it into a large elliptical orbit first. When the satellite is at apogee, adjust the attitude above the satellite to ignite the rocket, so that the orbit of the satellite becomes the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions.