Issue 76

China: Launches Shiyan-25

20 Jun 2023: China launched the Shiyan-25 experimental satellite on an LM-6 from Taiyuan. Official sources noted only that Shiyan-25 entered the desired orbit and will satellite will mainly be used to carry out new Earth-observation technology experiments. Launch Video . - Shiyan-25 is currently in a 307 x 321 km x…

20 Jun 2023: China launched the Shiyan-25 experimental satellite on an LM-6 from Taiyuan. Official sources noted only that Shiyan-25 entered the desired orbit and will satellite will mainly be used to carry out new Earth-observation technology experiments. Launch Video.

Shiyan-25 is currently in a 307 x 321 km x 96.6 deg sun-synchronous orbit with 10:30 local time orbital plane.

-Other than being an Earth imaging satellite, there is little additional information available.

-Shiyan-25 has the lowest altitude of any Shiyan satellite. The nearest orbit is Shiyan-11 at 476.6×463.8.

-Shiyan-25’s orbit is also the lower than any of the Yaogan satellites, the nearest being Yaogan-6 at 470x439kms.

-Shiyan-25 is even orbiting lower than any of the Gaofen satellites, the nearest being Gaofen-14 at 486.7x 484.2kms. This includes all of the Jilin imagery satellites, all of which are in orbits greater than 519kms.

-The only Chinese active satellites operating at lower orbits than Shiyan 25 are: 1) Longxia Yan 1 (2020, 266x253kms; 2) XJS C (2020, 267.4×254.7); and 3) Shaoniang Xing (2018, 308x305kms).

-Shiyan-25 is operating just beyond Very Low Earth Orbit (VLEO). VLEO satellites orbit at altitudes of between 150 to 300 kilometers, much lower than most satellites. These lower altitudes require propulsion to counter the relatively rapid orbital decay, due to much higher atmospheric drag. But they offer cost and performance incentives in the form of reduced power needs for data transmission, lower-latency data transfer, lower solar power-generation requirements, and higher resolution observation.

Shiyan-25 launch on a Long March-6 rocket from Taiyuan.

Mission patch for the CZ-6 Y12 launch carrying Shiyan-25.

Shiyan-25 in a 307 x 321 km sun-synchronous orbit.

Banner announcing the successful completion of the CZ-6 Y12 launch mission.