China deploys three-satellite system in Earth-Moon retrograde orbit

China deploys three-satellite system in Earth-Moon retrograde orbit
by Simon Mansfield
Sydney, Australia (SPX) Apr 22, 2025

China has successfully established the first three-satellite constellation operating in the distant retrograde orbit (DRO) of the Earth-Moon system, a major achievement in the nation's ongoing expansion of deep-space infrastructure, researchers announced during a recent symposium in Beijing.

The trio now orbiting in DRO comprises two spacecraft, DRO-A and DRO-B, launched in March last year, and a third, previously deployed satellite designated DRO-L. Together, they form a synchronized network following an 8.5-million-kilometer journey, the Technology and Engineering Center for Space Utilization (CSU) reported. The project forms part of the Chinese Academy of Sciences' flagship initiative, the "DRO Exploration" program.

Wang Wenbin, chief architect at CSU and CAS researcher, noted that the deployment places China in a leading position for utilizing this strategic orbit. He described the DRO as a "natural spaceport" ideally suited for sustained lunar operations and deeper solar system missions, thanks to its energy-efficient access and long-term orbital stability.

"This three-satellite infrastructure forms a backbone for supporting permanent operations throughout the Earth-Moon region," Wang said. He emphasized that the platform is critical for future endeavors, such as constructing lunar bases, supporting interplanetary spacecraft, and establishing deep-space telescopes.

He likened the effort to maritime expansion in previous centuries: "This constellation functions like early harbors and resupply posts, enabling extended voyages into uncharted domains."

Mission planners faced notable setbacks, including a malfunction in the upper stage of the launch vehicle that placed DRO-A and B off-course. Over the following four months, engineers employed a contingency strategy involving low-energy orbital transfers to correct the trajectory, using only 20% of the fuel typically required, said Zhang Jun, chief engineer at the Innovation Academy for Microsatellites.

Among the technological milestones validated by the mission were the first use of K-band inter-satellite communications over distances up to 1.17 million kilometers and the deployment of an advanced satellite-to-satellite orbit determination system. According to Wang, this autonomous navigation capability can match two days of ground-based tracking accuracy using just three hours of inter-satellite data.

The constellation reached full operational status in August and has since carried out several experiments validating DRO's role as a sustainable platform for future space infrastructure. CSU deputy director Wang Qiang remarked that the results "redefine how we approach cislunar development by substantially lowering entry barriers to long-term space presence."

Initiated in 2022, the CAS-led DRO program builds on groundwork laid since 2017. CSU has led payload integration and ground system design, while the Beijing Aerospace Control Center is responsible for flight control operations. The effort illustrates China's methodical strategy for advancing dominance in next-generation orbital systems.