China's Shijian Satellites Separate After Possible Historic Refuelling in Space

China’s Shijian-21 and Shijian-25 satellites have separated in geosynchronous orbit after months of being docked. The event follows a series of complex manoeuvres and could signal the completion of a historic refuelling operation. Observers first spotted the separation on 29 November near the geostationary belt. Shijian-21 was launched in October 2021 and previously towed a defunct Beidou-2 G2 navigation satellite to a higher graveyard orbit. In late June or early July, it rendezvoused with Shijian-25, which had been launched in January to test on-orbit refuelling and mission extension technologies.

The two satellites docked and later performed fuel-intensive manoeuvres to adjust their orbital plane. Their reduced inclination now aligns with that of some US satellites, possibly allowing future close approaches. The separation may confirm the success of the world’s first refuelling operation in geosynchronous orbit.

Chinese space authorities have released limited details about the mission. Most information comes from independent optical ground observations tracking the satellites’ movements. The separation of Shijian-21 and Shijian-25 demonstrates advances in on-orbit servicing. Such technology can extend the life of high-value satellites. The mission’s success, if confirmed, would mark a significant step for space sustainability and operational flexibility.