Issue 128

China: Launches SY-28B 02 Into Unusual Orbit

17 Aug 2025: Nearly six weeks after launching Shiyan-28B 01 (64753) China launched Shiyan-28B 02 (65226) on a Long March-4C launch vehicle from Xichang. According to official sources, the satellite entered the desired orbit and “will be mainly used for space environment exploration and related technology tests”. Both…

17 Aug 2025: Nearly six weeks after launching Shiyan-28B 01 (64753) China launched Shiyan-28B 02 (65226) on a Long March-4C launch vehicle from Xichang. According to official sources, the satellite entered the desired orbit and “will be mainly used for space environment exploration and related technology tests”. Both SY-28 spacecraft are in an unusually low inclination (11°) which was a first for China. To reach this inclination from Xichang requires China to conduct a “dog-leg” maneuver with the LM-4C as it headed to orbit. Launch Video. – China’s mission description of the Shiyan-28B satellites exactly matched that of the 6 Shiyan-27A-F (63599-63604) China launched into a sun-synchronous orbit on 18 Apr 2025. – SY-28B 02 is not co-planar with SY-28B 01 as their is a RAAN difference of ~33°. Both satellites are inclined 11° and orbiting at an average altitude of ~795km. They are orbiting on opposite sides of the Earth, ensuring that when one satellite is over the western hemisphere the other is over the eastern hemisphere. -The 6 SY-27 satellites are nearly evenly spaced in their 99.7° inclined orbit and have an average altitude of 1,049.5km.

Possible launch trajectory for Shiyan-28B 02, including the dog-leg maneuver needed to reach an 11° inclination (@mickeywzx via X).

Shiyan-28B 02 mission patch (nasaspaceflight.com).

Polar view of the Shiyan-28B constellation (spaceaware.io).

Shiyan-27 A-F and Shiyan-28B 01/02 constellation overview (spaceaware.io).