A rendering of a Tiandu test satellite. /DSEL

China will launch two experimental satellites into a lunar orbit to establish a communication channel between the moon and the Earth, the Deep Space Exploration Laboratory (DSEL) said on Saturday.

The twin satellites, known as Tiandu-1 and Tiandu-2, will fly in formation in the orbit around the moon to validate new technologies, including navigation calibrations and high-reliability signal transmissions.

Weighing 61 kg and 15 kg respectively, Tiandu-1 and Tiandu-2 have multiple payloads onboard, such as a Ka-band microwave communication system, space router and navigation and communication payloads.

They will be lifted into the Earth-moon transfer orbit together with Queqiao-2, a relay satellite for communications between the far side of the moon and Earth, after which they will undergo near-moon braking maneuver and enter an elliptic lunar orbit, Chen Xiao, commander of the Tiandu project at the DSEL, told Xinhua.

"In the orbit, the two satellites will carry out technology verifications on high-precision lunar orbit measurement by means of satellite-moon laser ranging and inter-satellite microwave ranging," said Chen.

The pair will provide a reference and foundation for the future establishment of the comprehensive Queqiao constellation system, Chen added.

The two satellites are expected to arrive at the Wenchang Spacecraft Launch Site in south China's Hainan Province around Wednesday, where they and the Queqiao-2 satellite are scheduled for launch in the first half of 2024, according to the DSEL.

Queqiao-2, already at the launch site, will enable communication between China's lunar rover and the ground station, providing relay support for the Chang'e-4, Chang'e-6, Chang'e-7 and Chang'e-8 missions.