China has successfully launched the world’s first three-satellite constellation in the distant retrograde orbit (DRO) region of space, connecting them with stable inter-satellite measurement and communication links. The CAS launched preliminary research and key technology development in this region in 2017, and initiated a pilot project to develop and launch three satellites in February 2022.
The three-satellite constellation, consisting of DRO-A, DRO-B, and DRO-L, was formed for the first time in August 2024. The plan included DRO-A permanently staying in the DRO, while DRO-B operates in Earth-moon space maneuver orbits. Chinese scientists have made significant breakthroughs in ranging fields since the set-up of the three-satellite constellation.
The team achieved a world-first by successfully verifying a 1.17-million-kilometer K-band inter-satellite microwave measurement and communication link, overcoming a major technological bottleneck in building large-scale constellations in cislunar space. They also validated a new space-based orbit determination system using satellite-to-satellite tracking, which significantly lowers the cost of orbit determination for cislunar spacecraft.
This achievement marks the first time internationally that orbit determination was verified using satellite-to-satellite tracking rather than ground stations. It provides an efficient solution for orbit determination, navigation, and timing across various cislunar orbits, supporting China’s future lunar exploration mission. The program will support China’s future lunar exploration mission by providing space-based inter-satellite measurement for rapid orbit determination and autonomous navigation services.
The DRO constellation can facilitate the establishment of communication links with lunar exploration mission spacecraft, and assist in the downlink of critical or emergency data. With this breakthrough, Chinese scientists have taken a significant step forward in developing the Earth-moon region of space and frontier exploration of space science.
Source: https://www.globaltimes.cn/page/202504/1332187.shtml