8-20 June: As predicted in the last Flash, China maneuvered both SJ-21 (49330) and SJ-25 (62485) into proximity with one another. Both satellites continue to make minor maneuvers and the satellites have ranged in separation from <1km to >100km and it is unknown if they were able to dock with one another (docking is likely required for re-fueling). Tracking the two satellites becomes more challenging once they are within 10km of one another due to resolution limitations of ground based telescopes. COMSPOC noted that the GSSAP satellite USA 270 (41744) adjusted its orbit to remain in proximity of SJ-21/25, likely in order to monitor China’s progress in conducting the world’s first on-orbit refueling in GEO. USA 271 (41645) did not adjust its orbit and is no longer in proximity. Watch COMSPOC Video of maneuvers for all 4 satellites (SJ-21/25 & USA 270/271) from 10-13 June. Also see amazing s2a systems video of close approach. Slingshot Aerospace also put together a video of the point of closest approach. China has not publicly shared any information regarding the ongoing test/demonstration. (I’m here for you guys if you’re willing).
– Per COMSPOC Reporting (current as of 17 Jun 2025):
- SHIJIAN-21 (SJ-21) and SHIJIAN-25 (SJ-25) have been engaged in RPO activity since 11 June, while USA 270 halted its previous eastward drift to position itself within the same longitude slot occupied by the SJ pair.
- On 11 June SJ-25 approached SJ-21, coming within roughly 50 km at approximately 01:21 UTC. Following this initial approach, both satellites executed several smaller maneuvers to closely align their orbital parameters, maintaining a mean longitude slot at~128°.
- SJ-21 and SJ-25 reached their closest proximity on 13 June between approximately 11:30 UTC and 13:00 UTC, after which they separated again. As of 16 June, the inter-satellite distance had increased significantly and is now greater than 100 km.
- Given the relatively short duration (~1.5 hours) of this close encounter, we (COMSPOC) have identified three potential scenarios:
- SJ-21 and SJ-25 successfully docked during that time period;
- SJ-21 and SJ-25 conducted a deliberate rehearsal maneuver but did not attempt docking;
- SJ-21 and SJ-25 initiated a docking attempt but aborted during final approach.
- It remains uncertain whether an actual docking event took place; additional observations will be required to confirm their operational activities and intentions.
- USA 271 continued drifting eastwards and is no longer maintaining proximity to the SJ-21/SJ-25 satellite pair. Conversely, USA 270 has executed several maneuvers, drifting eastward and stopping within the mean longitude slot currently occupied by SJ-21 and SJ-25.
– Reporting from the Joint Commercial Operations Cell from 17-20 Jun has noted an additional 2 maneuvers from SJ-21 and 3 maneuvers from SJ-25. The intent of the maneuvers is unclear.
Editor’s Note: SJ-21 and SJ-25 remain co-planar and continue to maneuver. If necessary, Chinese space operators will be able to attempt additional docking with minor orbital adjustments. An interesting question is what will China do with both satellites post-test. Assuming SJ-25 proves itself as a capable re-fueling platform I would expect China to place the satellite into a more populated orbital plane in order to support additional satellites…this would mean reducing its current inclination from 10.5° to 0-2°. SJ-21 is an even more interesting question. With a full fuel tank will China use the satellite again for a “debris mitigation” demonstration or place it into a more popular orbital plane in order to conduct GEO monitoring/inspection (with a proven “capture/tow” capability)? Plane changes of this magnitude are VERY rare due to the fuel expenditure required…and maybe that’s the point. With refueling capability China can increase the maneuverability of other satellites equipped to dock with SJ-25, leading to previously unseen tactics.
