Issue 102

China: An Update on the YG-35/36/39/42 Constellation

27 Jul: Can't get enough of Chinese LEO Formations? If so, read on! Here are my latest notes for all 15 triplets. List organized by 5 orbital planes. Orbital Plane #1 - YG-35 01 (49391/49390/49393): Trio is a mess . None of the satellites are co-planar and Lead now at 480km and may not be maneuverable. Trail2 is near…

27 Jul: Can’t get enough of Chinese LEO Formations? If so, read on! Here are my latest notes for all 15 triplets. List organized by 5 orbital planes.

Orbital Plane #1

– YG-35 01 (49391/49390/49393): Trio is a mess. None of the satellites are co-planar and Lead now at 480km and may not be maneuverable. Trail2 is near 492km and seems maneuverable but is nearly 1/2 an orbit behind Trail1. No longer in formation.

– YG-36 01 (53947/53943/59557): In formation with YG-42 02 (59557) as new Trail2. YG-42 02 (labeled in catalog as Obj A) replaced the now de-orbited YG-36 01B (53946). Trail2 has a slight RAAN offset.

– YG-39 03 (57990/57988/57986): In formation, Lead ~4min 15sec ahead of Trail1 and Trail1 ~1min 36sec ahead of Trail2. No RAAN offset.

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Orbital Plane #2

– YG-35 02 (52908/52907/59395): YG-42 01 replaced YG-35 02C as Trail2 in April 2024 (still mislabeled in SpaceTrak.org as YG-42 02). Trail2 has slight RAAN offset.

– YG-36 02 (54045/54043/54042): First trio to re-form after Trail2 altitude decrease in Jan 2023. Significantly larger Trail2 RAAN offset than other formations.

– YG-39 01 (57731/57728/57727): In formation, Lead ~4min 15 ahead of Trail1 and Trail1 ~1min 01sec ahead of Trail2. No RAAN offset.

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Orbital Plane #3

– YG-35 03 (53320/53318/53316): Trail2 satellite appears dead and heading for re-entry. Now at 464.7km. Likely candidate for YG-42 03? Lead is ~5min 33sec ahead of Trail1.

– YG-36 04 (54750/54746/54748): Trail2 SMA just below nominal 494.1km. Way out of formation. Recently started to drop altitude, may attempt to close gap with Trail1. Lead to Trail1 ~4min 55sec and Trail1 to Trail2 gap ~1hr 8min 44sec.

– YG-39 02 (57889/57890/57886): In formation, Lead ~3min 55sec ahead of Trail1 and Trail1 0min 46sec ahead of Trail2. No RAAN offset.

Orbital Plane #4

– YG-35 04 (53524/53526/53522): Trail2 has regained most of SMA and is now 492.5km but not close to being in formation. Trail2 recently started to drop altitude (see graph), may attempt to close gap with Trail1. Lead is ~6min 24sec ahead of Trail1 and Trail1 is ~40min 23sec ahead of Trail2.

– YG-36 05 (57456/57454/57452): In formation, Lead ~4min 34sec ahead of Trail1 and Trail1 ~1min 56sec ahead of Trail2. No RAAN offset.

Orbital Plane #5

– YG-35 05 (53761/53763/53760): Trail2 satellite SMA now just 2km (493km) below normal but still way out of formation. Trail2 recently started to drop altitude, may attempt to close gap with Trail1. Lead is ~5min 16sec ahead of Trail1 and Trail1 is ~36min 41sec ahead of Trail2.

– YG-36 03 (54372/54374/54376): Trail2 satellite SMA now just 2km (493km) below normal but still way out of formation. Trail2 recently started to drop altitude, may attempt to close gap with Trail1. Lead is ~5min 17sec ahead of Trail1 and Trail1 is ~36min 39sec ahead of Trail2.

– YG-39 04 (58145/58143/58141): In formation, Lead ~2min 59sec ahead of Trail1 and Trail1 ~2min 19sec ahead of Trail2. No RAAN offset.

Yaogan-35 01 Lead continued to lose altitude through late Jul 2024 (celestrak.org).

Yaogan-39 03 in formation, with Lead approximately 4 minutes 15 seconds ahead of Trail1 and Trail1 approximately 1 minute 36 seconds ahead of Trail2 (spaceaware.io).

Long road back: Yaogan-36 02 altitude history from Jan 2023 through Jul 2024 (celestrak.org).

Yaogan-36 04 formation viewed from the North Pole on 27 Jul 2024 (spaceaware.io).

Yaogan-35 04 Trail2 altitude history from Apr through Jul 2024 (celestrak.org).

The Yaogan-35/36/39 constellation organized into five orbital planes (celestrak.org).