Because the moon's body blocks direct radio communication with a probe, China first had to put a satellite in orbit above the moon in a spot where it could send signals to the spacecraft and to Earth.

"Smile Beijing" was sent into space by China's first lunar probe satellite Chang 'e-i, which sent back a signal of the song on December 4, 2007.

A fast design method for transfer orbit of lunar probe is presented using overlap conic curve method aimed at lunar landing transfer orbit and lunar satellite transfer orbit.