HELSINKI - A classified Chinese satellite launched in June is pulling orbital moves that would make a figure skater jealous, using a creatively tweaked Molniya orbit to sweep the geostationary belt like a cosmic janitor with a surveillance agenda.

Shijian-31 launched on a Long March 3B June 16 from Xichang spaceport, initially heading for geostationary transfer orbit. But it soon settled into a specialized Molniya orbit, joining China's Shiyan-10, TJS-13, and TJS-21 satellites. However, this is no ordinary Molniya - analysis by Integrity ISR and ComSpOC reveals a novel twist: instead of loitering over the northern hemisphere, Shijian-31 reaches apogee over the equator, letting it monitor satellites in geostationary orbit (GEO) at roughly 35,786 km altitude.

Traditional Molniya orbits use a 63.4-degree inclination to prevent perigee drift, giving satellites a long dwell time over high-latitude areas for communications or missile warning. Shijian-31, however, orbits once every 12.5 hours (not the usual 12), shifting about 15.7 degrees in longitude each lap. This allows it to sweep the entire GEO belt roughly every 23 days, with its apogee of about 39,900 km taking it a few thousand kilometers beyond GEO. ComSpOC called it a "satellite with an orbit we have never seen before."

Officially, Shijian-31 is part of a series of experimental satellites "mainly used for space environment exploration," per the China Aerospace Science and Technology Corporation (CASC), which provided no images. But Shijian satellites have also done refueling tests and space situational awareness. Integrity ISR notes it's tough to get a good look at Shijian-31 due to its perigee of under 2,000 km and its distance from U.S. GSSAP satellites. A small retrograde burn at perigee could drop its apogee to 36,671 km, letting it pass right through GEO.

"With SJ-31, Chinese space operators have displayed orbital mechanics mastery and more than a little creativity," Integrity ISR stated. Victoria Samson of the Secure World Foundation called the mission "pretty unusual," adding it might be part of a trend toward inspector satellites and heightened situational awareness in GEO. The U.S. has GSSAP, Russia has Luch 2, and China has previously studied creative orbits like looping a satellite around the moon for retrograde geosynchronous orbit.