Issue 88

YG-41 Settles In & An Overview of China’s GEO Imagers

27 Dec: China's Yaogan-41 GEO-based imager has settled into geostationary orbit at 123.3°E longitude. This places the spacecraft, with rumored 5m imagery resolution , just east of Gaofen-13-01. Gaofen-13-1 and Yaogan-41 now bracket the island of Taiwan. Yaogan-41's orbit is inclined 5° while Gaofen-13-1 is only…

27 Dec: China’s Yaogan-41 GEO-based imager has settled into geostationary orbit at 123.3°E longitude. This places the spacecraft, with rumored 5m imagery resolution, just east of Gaofen-13-01. Gaofen-13-1 and Yaogan-41 now bracket the island of Taiwan. Yaogan-41’s orbit is inclined 5° while Gaofen-13-1 is only inclined 0.2°. Increasing the Yaogan-41’s inclination will periodically bring it closer to Taiwan and other targets, presumably resulting in better imagery resolution. Of course, the higher inclination also takes the satellite further south and negatively impact resolution as well. China launched YG-41 on 15 Dec 2023 using a LM-5 with an extended payload fairing. Launch Video.

– YG-41 is China’s 4th optical satellite in GEO. In addition to the previously mentioned Gaofen-13-1, YG-41 joins the civilian Gaofen-4 (2015) and Gaofen-13-2 (2023). China also recently added the world’s first SAR imaging satellite in GEO, Ludi Tance 4-01.

-Chinese scientists have briefed that Gaofen satellites designated 8 or higher are associated with military/national security missions. All Yaogan designated missions are believed to have military/national security missions.

Gaofen-13-1 and 13-2 are believed to be capable of 15m resolution imagery.

– China may be experimenting with different inclination values for its GEO-based imagers. China has placed each successive satellite into a higher inclination…GF-4 at .1°, GF-13-1 at .2°, GF-13-2 at 2.4° and now YG-41 at 5°.

– All GEO imagers seem to be in orbits to provide constant surveillance of the Western Pacific and areas of potential conflict. GF-13-1 and YG-41 are located on either side of Taiwan and GF-13-02 is 2° East of Guam and <1° East of the Northern Marianas Islands.

– Ludi-Tance-4-01 is the world’s only GEO-based synthetic aperture radar (SAR) imager and located further west than any of the other GEO imaging satellites. It is also highly inclined at 15.9°, likely to provide the relative motion with the Earth’s surface to enable it’s expected 20m resolution. China classified Ludi-Tance-4 as a civilian satellite, it is unknown if the satellite is being used for military/national security missions.

China’s increasing GEO-based imaging capabilities and select areas of interest