Queqiao, Longjiang 1 & 2

Queqiao (Chinese: 鹊桥) is a Chinese artificial satellite serving as a communications relay for the Chinese rover of the Chang'e 4 mission that landed on the far side of the Moon and therefore cannot communicate directly with the Earth. The satellite was launched on May 20, 2018. It begins relaying data from the Lagrange L2 point of the Earth-Moon system from the end of 2018, the launch date of Chang'e 4. Queqiao is a small 425 kg satellite using a CAST-100 platform from its manufacturer the Chinese Academy of Space Technology (CAST). The platform is stabilized on three axes and its energy is supplied by solar panels. The propulsion is ensured by 4 small engines burning hydrazine with a thrust of 130 Newtons. Its main payload is its radio transceiver. This has 4 X-band channels for links with the spacecraft on the lunar surface (256 kilobits/second) and an S-band channel for data transmission to Earth (2 gigabits/second). It uses a 4.2-meter diameter parabolic antenna deployed in orbit.

As part of the Chang'e 4 mission, two microsatellites (45 kg each) named Longjiang-1 and Longjiang-2 will be deployed into lunar orbit to observe the sky at very low frequencies (1 MHz-30 MHz), corresponding to wavelengths of 300m–10m, with the aim of studying energetic phenomena from celestial sources.