“Shijian-31, however, is using a Molniya type orbit to reach apogee over the equator, allowing it to perform sweeps of GEO. Integrity ISR first flagged Shijian-31 in a Molniya orbit in a June 26 post, using orbital data from SpaceTrack. ISR explained that the satellite is in a unique orbit, allowing Shijian-31 to loiter over the equator and monitor satellites orbiting in GEO, which is situated at around 35,786 km above the equator…”
“ComSpOC also noted the activities of Shijian-31 in a July 21 post on X, describing it as a ‘satellite with an orbit we have never seen before.’ The post includes a video illustrating Shijian-31’s orbit, also showing how it sweeps around GEO over time, gaining a unique view down on the entire GEO belt…”
“Integrity ISR states that it may be extremely challenging to get a good glimpse of Shijian-31 and ascertain its payloads and capabilities. Its perigee of just under 2,000 km is well above most low Earth orbit remote sensing satellites, and it passes thousands of kilometers away from spacecraft such as the U.S. GSSAP series in GEO. At the same time, if China wanted to intersect the GEO belt, this could be done with a relatively small fuel cost. A relatively small retrograde burn at perigee, bringing a velocity change of 50 meters per second, would ‘lower apogee to roughly 36,671 km, resulting in SJ-31 passing directly through the GEO neighborhood as it completes its orbit.’ ”
https://spacenews.com/chinas-shijian-31-satellite-is-sweeping-geo-using-a-unique-orbit/