Issue 105

SY-12 01 Raises Orbit to Reverse Drift & Visits TJS-3 & 10

15 Sep: Shiyan-12 01 (SY-12 01/50321)), which has been rumored to be the Chinese version of GSSAP , raised its orbit on 10 Sep as it approached its historic turnaround point of 178.9°E. On 9 Sep the satellite was at 176.0°E and drifting further east at a rate of 0.6° per day. From 10-11 Sep the satellite increase…

15 Sep: Shiyan-12 01 (SY-12 01/50321)), which has been rumored to be the Chinese version of GSSAP, raised its orbit on 10 Sep as it approached its historic turnaround point of 178.9°E. On 9 Sep the satellite was at 176.0°E and drifting further east at a rate of 0.6° per day. From 10-11 Sep the satellite increase its altitude a total of 91.1kms and is now 45.5kms above GEO initiating a westward drift of 0.6° per day. During its wanderings, SY-12 01 passed the TJS-3 and TJS 10 satellites twice (5 Sep when it was heading east and then again on 15 Sep as it moved west.) Solar phase angles for imaging TJS-3 and 10 were marginal on 5 Sep but excellent on 15 Sep.

– China launched SY-12 01 and 02 on 23 Dec 2021 on a LM-7A from Wenchang. There has been open source comparison with the US GSSAP mission.

– In 2022 there were some interesting interactions between USA270 (a GSSAP satellite) and both Sy-12 satellites (watch Video).

– SY-12 01 began it most recent eastward journey on 14 Jan 2024 when it decreased its altitude ~91km and transitioned from 46.1km above GEO to 44.7km below GEO. China conducted this maneuver when SY-12 01 was at 18.1°E.

– SY-12 01 maintained an eastward drift for 240 days until its maneuver on 10 Sep.

– This is similar to the 260 days SY-12 01 operated below GEO from 22 Aug 2022 – 9 May 2023.

– SY-12 01 conducted far fewer maneuvers during its current eastward drift than was observed during its transit in 2022-23 (see graphs).

-China has been operating its TJS-3 and TJS-10


experimental satellites in proximity with one another since TJS-10’s arrival in GEO on 9 Nov 2023. Currently the satellites maintain ~50-70km separation (TJS-3 @ 172.97°E/TJS-10 @ 172.89°E.)

– On 5 Sep 2024 at 07:31Z, SY-12 01’s orbit took it within 43km of TJS-3 and 79.1km of TJS-10. There was no apparent maneuvering from any of the satellites just prior to, or during this time. At this time the solar phase angle (SPA) was marginally favorable for SY-12 01 to image TJS-3 and unfavorable for imaging TJS-10.

– On 15 Sep at ~1810Z, SY-12 01 had a POCA with TJS-3 of ~61km and TJS-10 of ~106km. SPA for SY-12 01 to image both satellites was excellent. There were no apparent maneuvers from any of the satellites just prior to or during this time.