After being linked for almost six months, China’s Shijian 21 and Shijian 25 separate
After rendezvousing and doing repeated docking tests in June and July and then remaining linked since then, China’s Shijian 21 and Shijian 25 test satellites have now separated.
Optical ground observations Nov. 29 made by S2a systems, a Swiss company which develops and operates customized systems for optical space surveillance worldwide, reveal that the two satellites have now separated in geosynchronous orbit, close to the geostationary belt (GEO) at 35,786 km above Earth’s equator. The orbits of the pair are inclined by 4.6 degrees with respect to GEO.
The article at the link speculates that the spacecraft were doing refueling tests while docked, but while a good guess this has not been confirmed anywhere. China has said nothing.
Shijian-21 was launched in 2021, and was used to grab a defunct Chinese geosynchronous satellite and tug it to a graveyard orbit. Shijian-25 was launched in January 2025, apparently intended to test robotic servicing of satellites. These maneuvers with Shijian-21 appear to be part of those tests. Whether those tests included refueling is uncertain, though possible. If Shijian-21 proceeds to do additional satellite tug maneuvers then it will strongly suggest this refueling occurred and was successful.
After rendezvousing and doing repeated docking tests in June and July and then remaining linked since then, China’s Shijian 21 and Shijian 25 test satellites have now separated.
Optical ground observations Nov. 29 made by S2a systems, a Swiss company which develops and operates customized systems for optical space surveillance worldwide, reveal that the two satellites have now separated in geosynchronous orbit, close to the geostationary belt (GEO) at 35,786 km above Earth’s equator. The orbits of the pair are inclined by 4.6 degrees with respect to GEO.
The article at the link speculates that the spacecraft were doing refueling tests while docked, but while a good guess this has not been confirmed anywhere. China has said nothing.
Shijian-21 was launched in 2021, and was used to grab a defunct Chinese geosynchronous satellite and tug it to a graveyard orbit. Shijian-25 was launched in January 2025, apparently intended to test robotic servicing of satellites. These maneuvers with Shijian-21 appear to be part of those tests. Whether those tests included refueling is uncertain, though possible. If Shijian-21 proceeds to do additional satellite tug maneuvers then it will strongly suggest this refueling occurred and was successful.










