Issue 87

China’s YG-35/36/39 Constellation: A Closer Look

24 Dec 2023: China launched its first Yaogan-35 satellites on 11 June 2021. Over the next 30 months it conducted another 14 LM-2D launches from Xichang, placing 45 satellites into five orbital planes, all ~495 km and inclined 35°. The spacing between the satellites appears consistent for 9 of the 15 triplets, -…

24 Dec 2023: China launched its first Yaogan-35 satellites on 11 June 2021. Over the next 30 months it conducted another 14 LM-2D launches from Xichang, placing 45 satellites into five orbital planes, all ~495 km and inclined 35°. The spacing between the satellites appears consistent for 9 of the 15 triplets,

– Spacing: 9 of the 15 of the YG-35/36/39 triplets operate in a similar Lead-Trail-Trail formation, with the lead satellite being considerably further ahead than the two followers.

– On average, the lead satellite is 5 min 16 sec ahead of Trail 1, and Trail 1 is 1 min 51 sec ahead of Trail 2. There is some variance between the formations. Discounting recently deployed trios (or those with anomalous satellites), the range between Lead and Trail 1 is ~2 min 49 sec through 9 min 39 sec. The range between Trail 1 and Trail 2 is 0 min 35 sec through 3 min 28 sec.

-Three of the trios (YG-36-02, YG-39-02 & YG-39-03) appear to have an elongated formation with nearly equal distance between all three satellites. China is potentially experimenting with different spacing to optimize performance.

– YG-35-02 & YG-36-01 appear to have had an anomaly with one of their spacecraft, and are not able to maintain formation.

– YG-35-02C (SCC 52909) has lost nearly 60 km in altitude, and has not maneuvered in months. YG-36-01B (53946) has lost 47 km, and also has not maneuvered in over six months.

– It is too early to make a determination of the YG-39-05 satellites at this time.

– China has launched other satellites with same 35° inclination as the YG-35/36/39 satellites.

– From 2018-2021, China launched 30 Yaogan-30 satellites which are suspected of having a SIGINT mission, especially to detect ships by their radio emissions. China also launched the YG-30 satellites in batches of three, but they are evenly spaced 120° apart in their orbital planes. Yaogan-30 satellites also orbit ~100 km higher than YG-35/36/39 satellites.

– Another 35° inclined system is the eight XJS experimental

satellites. China launched XJS A & B on a LM-2C in 2018. There were two launches in 2020: one with XJS C, D, E & F on a LM-2D; and XJS G & H on a LM-11. All launches were from Xichang. In addition to sharing the same inclination, the XJS satellites operated at an altitude of 460-475 km, much closer to the 500 km altitude of the YG-35/36/39 satellites.

– Open source reporting notes the XJS satellites’ mission is to conduct tests on inter-satellite links and Earth observation technology.

Jun 2021 - Dec 2023: China Launched a 45 Satellite ISR Constellation

YG-36-03 Formation

YG-35-05 Formation

Elongated Formation (Dec 2023): Likely Transitory (YG-39-02)