Issue 142

I Have the Watch: USA 324 Begins Monitoring SJ-29A/B

29 Mar 2026: On ~15 Mar 2026 USA 324 (51280), a US GSSAP inspector satellite, arrived in vicinity of SJ-29A & 29B (67302 & 67303) at ~73.0°E longitude. Recall that the US had stationed USA 325 (51281) in an orbit to observe both SJ-29A/B shortly after the Chinese satellites arrived in GEO (see 9 Feb and 9 Mar Flash…

29 Mar 2026: On ~15 Mar 2026 USA 324 (51280), a US GSSAP inspector satellite, arrived in vicinity of SJ-29A & 29B (67302 & 67303) at ~73.0°E longitude. Recall that the US had stationed USA 325 (51281) in an orbit to observe both SJ-29A/B shortly after the Chinese satellites arrived in GEO (see 9 Feb and 9 Mar Flash articles). TLE data from 16 Mar 2026 shows USA 324 positioned slightly to the west of SJ-29A/B and USA 325 positioned slightly to the east. (see graphic). From its position to the west of SJ-29A/B, USA 324 had favorable solar conditions to to observe both SJ-29A (POCA ~58km) and 29B (POCA ~106km) as the pair travelled from South to North. By 19 Mar 2026, USA 325 had decreased its average altitude and headed east at ~0.7°/day and was no longer in position to observe SJ-29A/B. From 19-29 Mar USA 324 gradually moved to the east, eventually settling into USA 325’s previous orbit.

As of 4 Apr the SJ-29-A and B continue to maintain ~50-70km absolute separation, most of this is due to in-track differences as the two satellites are nearly perfectly plane-matched. Both satellites remain IVO of 73.0° E longitude.

Thankfully the COMSPOC Ops team put together a brief video showing the changing of the Guard.








30 Mar: USA 324 Has Optimal Lighting Conditions for Observing SJ-29A/B @ ~0110Z During North to South Transit