China's Chang'e-4 probe entered a planned orbit Sunday morning to prepare for the first-ever soft landing on the far side of the moon, the China National Space Administration (CNSA) announced.

The probe has entered an elliptical lunar orbit with the perilune at about 15 km and the apolune at about 100 km at 8:55 a.m. Beijing Time, said CNSA.

Since the Chang'e-4 entered the lunar orbit on Dec. 12, the ground control center in Beijing has trimmed the probe's orbit twice, and tested the communication link between the probe and the relay satellite Queqiao, or Magpie Bridge, which is operating in the halo orbit around the second Lagrangian (L2) point of the earth-moon system.

The space engineers also checked the imaging instruments and ranging detectors on the probe to prepare for the landing.

The control center will choose a proper time to land the probe on the far side of the moon, according to CNSA.

The Chang'e-4 probe, including a lander and a rover, was launched by a Long March-3B carrier rocket on Dec. 8 from the Xichang Satellite Launch Center in southwest China's Sichuan Province.