Queqiao

Description

Queqiao will be the communications relay satellite for the Chang'e 4 lunar farside mission. It launched on 21 May at 5:28 a.m. local time (20 May 21:28 UT, 20 May 5:28 p.m. EDT) from Xichang Satellite Launch Center in China, on a Long March 4 into a halo orbit about the Earth-Moon L2 Lagrange point. From that position, it will enable communications between the Chang'e 4 lander on the lunar farside and the Earth. Launching with Queqiao will be two scientific microsatellites, Longjiang-1 and Longjiang-2.

The spacecraft is equipped with a 4.2 m dish antenna. In addition to its communication relay equipment, Queqiao will also carry the Netherlands-China Low Frequency Explorer (NCLE), a radio-astronomy experiment designed to measure radio emissions back to the early universe, study space weather, and observe the radio environment in the vicinity of the Earth and Moon. NLCE is described as a pathfinder experiment, experience with its operation and data is planned to be used to aid in the development of future radio astronomy instruments.

After launch, Queqiao use a lunar swingby transfer orbit to reach the L2 point. It entered a halo orbit around L2 on June 14.

The Longjiang-1 and -2 microsatellites each have a mass of 47 kg and carry radio astronomy instrumentation. Longjiang-2 also carried a Saudi Arabian built camera. The plan was to fly the satellites in close 300 x 3000 km orbits to permit astronomical interferometry, but Longjiang-1 failed to enter lunar orbit. Longjiang-2 entered a 350 x 13700 km altitude lunar orbit on 25 May. The microsatellites were developed by the Harbin Institute of Technology.

Queqiao means "Bridge of Magpies" referring to a Chinese folktale about magpies forming a bridge with their wings to allow Zhi Nu, the seventh daughter of the Goddess of Heaven, to reach her husband. Longjiang means "dragon river".