How will Queqiao-2 operate?
To play its role, Queqiao-2 will be inserted into a specialized 24-hour-period elliptical “frozen orbit” that allows it to maintain a line of sight with both Earth ground stations and the Chang’e-6 mission in the Apollo crater for long periods of time.
This orbit is different from that of Queqiao-2’s predecessor, Queqiao, launched in 2018. That spacecraft facilitated the first-ever soft landing on the lunar far side from a halo orbit around Earth-Moon Lagrange point 2, around 65,000 kilometers or 40,000 miles beyond the Moon. This provided the support for the Chang’e-4 lander and rover mission, which are still active in Von Kármán crater to this day. The new, enhanced Queqiao-2 will also help support Chang’e-4 after assisting Chang’e-6, the surface operations of which will last only a few Earth days at most.
The high stability of Queqiao-2’s orbit demands minimal fuel for maintenance, meaning a longer lifetime, allowing it to support further missions: Chang’e-7 (2026) and Chang’e-8 (2028). These will attempt to land near the lunar south pole with objectives including seeking water and testing in-situ resource utilization techniques, such as making bricks from lunar regolith. Queqiao-2 will switch to a 12-hour period orbit to better support these later south polar missions.
Queqiao-2 will also carry three science payloads. These will play a part in the overall science goals of the multi-spacecraft Chang’e-7 mission. The Energetic Neutral Atom Imager for Earth’s magnetotail imaging (GENA) and the Extreme Ultraviolet Camera for Earth’s plasmasphere observation (EUC) will study Earth’s magnetotail and plasmasphere, and how the solar wind interacts with the Earth’s magnetosphere and the ionosphere.
A Moon-Earth very-long-baseline interferometry (VLBI) measurement and observation experiment (LOVEX) is also included, designed to improve the accuracy of determining the orbits of spacecraft in deep space. It will create a 400,000-kilometer (250,000-mile) baseline between Queqiao-2 and radio telescopes on Earth. The experiment will also carry out radio astronomical observations and test capabilities for astrophysics and astrometry, making precise measurements of stars’ locations in the sky.
The mission will also serve as a platform to test possible future lunar infrastructure. The launch will also send experimental CubeSats named Tiandu-1 and Tiandu-2 to the Moon. The satellites were developed by China’s Deep Space Exploration Laboratory and will test lunar communications and navigation payloads. The pair will fly in formation as pathfinders for a planned Queqiao lunar satellite constellation that will provide services for future robotic and crewed missions to the Moon, including the China-led International Lunar Research Station (ILRS).
The 61-kilogram (134-pound) Tiandu-1 carries a laser retroreflector and a Ka dual-band integrated communication payload. The smaller, 15-kilogram (33-pound) Tiandu-2 carries a communications instrument. NASA and the European Space Agency are likewise looking to develop their own networks of communications and navigation satellites to support the Artemis program. China’s wider Queqiao concept could also be expanded to various Lagrange points, Venus, and Mars to facilitate deep space communication.
Queqiao-2 could also potentially support lunar far side or polar missions of other countries. Beijing is actively seeking partners for its ILRS initiative—a lunar program separate from NASA’s Artemis—and supporting infrastructure could add to the attraction. This means Queqiao-2 could play a diplomatic part in China’s space efforts, in addition to its role as a bridge for lunar science and exploration.