Issue 118

Pulling The Plug: 9 of 15 Yaogan Formations In Trouble

31 Mar: Between 18-30 March 2025, Chinese space operators significantly increased the average altitude for 9 of 10 of their Yaogan-35 and 36 (YG-35 & YG-36) Trail1 satellites. Specifically, China raised the average altitude for the Trail1 satellites for the following triplets: YG-35 01 (49390), 35-02 (52907), 35-03…

31 Mar: Between 18-30 March 2025, Chinese space operators significantly increased the average altitude for 9 of 10 of their Yaogan-35 and 36 (YG-35 & YG-36) Trail1 satellites. Specifically, China raised the average altitude for the Trail1 satellites for the following triplets: YG-35 01 (49390), 35-02 (52907), 35-03 (53318), 35-04 (53526), 35-05 (53763), 36-01 (53943), 36-02 (54043), 36-03 (54374) and 36-04 (54746). Only YG-36 05 remains in formation. There were no corresponding SMA increases from either the Lead or Trail2 satellites and as a result these formations rapidly dissolved as the Trail1 satellites now are traveling slower (have a longer orbital period) relative to their Lead and Trail2 counterparts. Operating at different altitudes also affects the rate of RAAN progression and the Trail1 satellites will no longer be co-planar with their partners if they remain at different average altitudes.

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China could easily lower the Trail1 satellites to rejoin their partners at the time of their choosing. The longer this takes the greater the RAAN differential. Conversely, as we noted in the last Flash, 4 of these triplet formations seem to be having problems with their Lead satellites and a few of the Trail2 satellites have been problematic as well. There is the possibility that China has increased the average altitude of the Trail1 satellite to operate independently from their partners (which may be inoperable) to maximize the Trail1 satellites’ capabilities (specifics of which remain unknown). The coming weeks will be telling.

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The 6 remaining Yaogan triplets remaining in formation are also those most recently launched. All five sets of Yaogan-39 triplets remain in formation (all launched between Aug-Dec 2023) as does the YG-36 05 (launched Jul 2023.)

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All 5 of the orbital planes have at least 1 YG-39 triplet and one of the planes has 2 triplets (YG-39 05 and YG-36 05).